bicol international airport development project section vi...

Bicol International Airport Development Project Section VI- Technical Specifications Part B – Other Requirements


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ANNEX C - ENVIRONMENTAL MONITORING PLAN

Parameter Location Frequency and

Cost Responsibility

Construction Phase

Dust control Stockpiles Daily check-up/part of administrative cost

Project Engineer

Air quality – TSP, NOx, SOx Construction site Once before commencement of construction activities and 3 times within the entire 30 month duration at 6 locations per Lot.

Air quality – TSP, NOx, SOx

Noise Construction site and vicinity

Once before commencement of construction activities and 3 times within the entire 30 month duration at 6 locations per Lot.

Contractor

Inspection of construction spoils and sanitation at workplace

Construction site Daily / part of construction cost

Contractor

Inspection of flooding/ponding Construction site Daily / part of construction cost

Contractor

Runoff to drainage canal Exposed surfaces and stockpiles

Rainy periods / part of administrative cost

Project Engineer

Traffic monitoring Adjacent streets Daily / part of construction cost

Contractor / security personnel

Coordination meetings to ensure safety and adherence to approved plans

Project management office

Weekly/ part of construction cost

Project contractors (structural, electrical, plumbing, etc)

Soil creep Construction site Daily check-up Project engineerLand acquisition (property acquired and paid)

Project site Prior to start of construction Project management team

No. of families resettled Project site and resettlement areas

Prior to start of construction Project management team

Employment profile Construction site Weekly reporting / part of construction cost

Project management team /


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ANNEX D - ENVIRONMENTAL IMPACT AND MITIGATING MEASURES

Potential Environmental

Impact Mitigating Measures Manner of

Implementation Institutional Responsibility

Construction Phase Land Use Change in existing land use from agricultural to institutional/commercial

Coordination with the LGU and DAR regarding shift of existing land use

Conversion of affected agricultural lands; Secure Land Conversion Certificate from DAR Updating of land use/zoning plan

DOTC c/o project contractor PPDO and MPDO

Topography and Drainage

Obstruction to natural drainage pattern

Construction of temporary works such as deviation channels, barriers and trenches around the stock piles.

The Contractor should be directed to implement these mitigating measures as embodied in the Terms of Reference (TOR).

DOTC c/o project contractor

Geologic Hazard Localized settlement due to dewatering in excavated areas, ground shaking

Foundation works should diligently observe localized creep and lateral spread of foundation soil to implement mitigating measures.

Strict implementation of and adherence to the National Building Code on provisions for seismic loading


Water Quality Sedimentation/siltation of drainage or waterways

Construction of silt traps Protection of rivers and riverbanks


Pollution of water bodies due to disposal of construction wastes including hazardous substances

Undertake waste segregation

Develop construction waste management plan


Wastewater from worker’s camps

Temporary toilet facilities will be utilized to avoid contamination of surface and groundwater by sewage.

The temporary toilet facilities shall be kept clean and sanitary at all times.



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Potential Environmental Impact

Mitigating Measures Manner of Implementation

Institutional Responsibility

Health and Safety Impact of construction activities on welfare and safety of workers and passersby.

Wearing of safety gadgets such as hard hats, gloves, safety belts, rubber boots, goggles, etc. will be a mandatory requirement for workers. Safety signs/reminders will be posted in strategic areas within the construction area Fire extinguisher shall be present at all times at the jobsite. Sufficient lighting shall be installed in some dark areas.

Construction area will be fenced. Workers will be oriented on basic rules on personal safety and conduct, i.e., reporting hazards, injuries, wearing of safety gadgets, etc. Gambling, drinking intoxicating liquor will not be allowed within the construction site. Workers will be strictly required to observe order in the performance of their duties.


Peace and Order Breach of peace and order due to influx of construction works

Security guards shall be assigned to monitor and maintain peace and order due to the presence of migrant workers

Hiring of security personnel. Coordination with the LGU and adjacent communities

Contractor

Air Quality Increase in dust emission from site clearing, civil works, earthmoving activities and movement of vehicles.

Dust control at the stock pile of aggregates through regular water sprinkling

Water sprinkling shall be undertaken during dry and windy conditions.


Increase air emissions from movement of heavy equipment, generators, and other construction vehicles.

Maintenance of construction vehicles and equipment

Include in the TOR of contractor

Project contractor

Noise Noise disturbance from the construction activities.

Heavy construction works should be scheduled during daytime hours only.

Heavy construction shall be scheduled during daytime; Activities generating less noise shall be allowed at night time, if necessary. Fencing of the construction area. Coordination with LGU and affected communities


Biological Clearing of existing vegetation

Design a landscaping plan Revegetation / re-greening of airport and its vicinity



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Potential Environmental Impact

Mitigating Measures Manner of Implementation

Institutional Responsibility

Construction Wastes Generation of construction debris and other solid wastes

Collection and recycling of construction wastes. To be offered to junk shops as scrap material. Handling and storage of potential contaminants under strict conditions

Stockpile, waste, excess and scrap materials will be hauled out on a weekly basis. Recyclable materials will be reused in other projects of the contractor. Other wastes or discarded materials shall be properly stored and disposed of(hauling out in trash bags).


Aesthetics Impact on aesthetics due to generation of mud in streets and cluttering of construction spoils, tools and equipment

Workers and sweepers will be assigned to keep area clean. Contractors shall be required to keep work site clean

Include in contract with contractor

DOTC c/o contractor

Traffic Traffic congestion Design of a traffic

management plan Traffic and security enforcers will be assigned to ensure the smooth delivery of materials and prevent blockage of adjacent streets. Coordination with LGU and affected communities


Increased employment opportunities

Priority in hiring will be given to qualified locals from the barangay and adjacent community.

Implementation of livelihood and skills training program. Require contractors to prioritize qualified locals from the affected barangays.

DOTC in cooperation with Provincial Government and Municipalities of Daraga and Camalig

Post-Construction (Abandonment) Phase Demolition of temporary structures causing dust emission

Watering of areas prone to dust emission

Require contractors to water areas during cleaning/clearing activities

Contractor

Noise Regulate noise generating activities

Coordination with LGU and affected communities

Contractor

Generation of construction spoils

Collection and hauling of construction spoils on a daily basis

To be offered to junkshops or used in other construction projects

Contractor

Decommissioning of septic tank

Backfilling of empty septic tank with soil and proper compaction prior to concreting

Contracting a desludging company or contractor of the portable toilets in the hauling of remaining contents of septic tank

Contractor

Aesthetics Landscaping of the site as part of the landscaping plan

Included in design of the project

Contractor

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SITE DEVELOPMENT WORKS

Earthworks and Security Fence/Gates

PART C - EARTHWORKS

Bicol International Airport Development Project Part C – Earthwork Section VI- Technical Specification Clearing and Grubbing

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ITEM 100 - CLEARING AND GRUBBING

PART 1 – GENERAL 1.1 Description

This Item shall consist of clearing, grubbing, removing and disposing all vegetation and debris as designated in the Contract, except those objects that are designated to remain in place or are to be removed in consonance with other provisions of this Specification. The work shall also include the preservation from injury or defacement of all objects designated to remain.

PART 2 – PRODUCTS (Not Applicable) PART 3 – EXECUTION 3.1 General

The Engineer will establish the limits of work and designated all trees, shrubs, plants and other things to remain. The Contractor shall preserve all objects designated to remain. Paint required for cut or scarred surface of trees or shrubs selected for retention shall be an approved asphaltum base paint prepared especially for tree surgery.

3.2 Clearing and Grubbing

All surface objects and all trees, stumps, roots and other protruding obstructions, not designated to remain, shall be cleared and/or grubbed, including moving as required, except as provided below:

a. Removal of undisturbed stumps and roots and nonperishable solid objects with a

minimum of 1 meter below subgrade or slope of embankments will not be required.

b. In areas outside of the grading limits of cut and embankment, stumps and nonperishable solid objects shall be cut off not more than 150 mm (6 inches) above the ground line or low water level.

c. In areas to be rounded at the top of cut slopes, stumps shall be cut off flush with or

below the surface of the final slope line.

d. Grubbing of pits, channel changes and ditches will be required only to the depth necessitated by the proposed excavation within such areas.

Except in areas to be excavated, stump holes and other holes from which obstructions are removed shall be backfilled with suitable material and compacted to the required density.

3.3 Individual Removal of Trees or Stumps

Individual trees or stumps designated by the Engineer for removal and located in areas other than those established for clearing and grubbing and roadside cleanup shall be removed and disposed of as specified under Sub-item 3.2 except trees removed shall be cut as nearly flush with the ground as practicable without removing stumps.

Bicol International Airport Development Project Part C – Earthwork Section VI- Technical Specification Clearing and Grubbing

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PART 4 – METHOD OF MEASUREMENT AND PAYMENT 4.1 Method of Measurement

Measurement will be by one or more of the following alternate methods:

1. Area Basis. The work to be paid for shall be the number of hectare and fractions thereof acceptably cleared and grubbed within the limit indicated on the Plans or as may be adjusted in field staking by the Engineer. Areas not within the clearing and grubbing limits shown on the plans or not staked for clearing and grubbing will not be measured for payment.

2. Lump-Sum Basis. When the Bill of Quantities contains a Clearing and Grubbing

lump-sum item, no measurement of area will be made for such item.

3. Individual Unit Basis (Selective Clearing). The diameter of tree will be measured at a height of 1.4m (54 inches) above the ground. Tree less than 150 mm (6 inches) in diameter will not be measured for payment.

When Bill of Quantities indicates measurement of trees by individual unit basis, the units will be designated and measured in accordance with the following schedule of sizes:

Diameter at height of 1.4 m Pay Item Designation

Over 150 mm to 900 mm Small

Over 900 mm Large

4.2 Basis of Payment

The accepted quantities, measured as prescribed in Sub-item 4.1, shall be paid for at the Contract unit price for each of the Pay Items listed below that is included in the Bill of Quantities, which price and payment shall be full compensation for furnishing all labor, equipment, tools and incidentals necessary to complete the work prescribed in this Item.

Payment will be made in accordance with the Bill of Quantities. *****

Bicol International Airport Development Project Part C - Earthwork Section VI- Technical Specification Removal of Structures and Obstructions

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ITEM 101 - REMOVAL OF STRUCTURES AND OBSTRUCTIONS PART 1 – GENERAL 1.1 Description This Item shall consist of the removal, wholly or in part, and satisfactory disposal of any

obstructions which are not designated or permitted to remain, except for the obstruction to be removed and disposed of under other Items in the Contract. It shall also include the salvaging of designated materials and backfilling the resulting trenches, holes, and pits.

PART 2 – PRODUCTS

(Not Applicable) PART 3 – EXECUTION 3.1. General

The Contractor shall perform the work described above, within and adjacent to the site and the roadway, as shown on the Plans or as directed by the Engineer. All designated salvageable material shall be removed, without unnecessary damage, in sections or pieces which may be readily transported, and shall be stored by the Contractor at specified places on the project area. Cavities left by structure removal shall be filled with acceptable materials to the level of the surrounding ground and, if within the prism of construction, shall be compacted to the required density.

PART 4 – METHOD OF MEASUREMENT AND PAYMENT

4.1 Method of Measurement

When the Contract stipulates that payment will be made for removal of obstructions on lump-sum basis, the pay item will include all structures and obstructions encountered within the roadway. Where the contract stipulates that payment will be made for the removal of specific items on a unit basis, measurement will be made by the unit stipulated in the Contract. Whenever the Bill of Quantities does not contain an item for any aforementioned removals, the work will not be paid for directly, but will be considered as a subsidiary obligation of the Contractor under other Contract Items.


The accepted quantities, measured as prescribed in Sub-item 4.1 shall be paid for at the Contract unit price or lump sum price bid for each of the Pay Items listed below that is included in the Bill of Quantities which price and payment shall be full compensation for removing and disposing of obstructions, including materials, labor, equipments, tools and incidentals necessary to complete the work prescribed in this Item. The price shall also include backfilling, salvage of materials removed, their custody, preservation, storage on the right-of-way and disposal as provided herein.

Payment will be made in accordance with the Bill of Quantities.

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Bicol International Airport Development Project Part C - Earthwork Section VI- Technical Specification Excavation

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ITEM 102 – EXCAVATION PART 1 – GENERAL 1.1 Description

This Item shall consist of roadway and borrow excavation, and the disposal of material in accordance with this Specification and in conformity with the lines, grades and dimensions shown on the Plans or established by the Engineer.

1.1.1 Roadway Excavation

Roadway excavation will include excavation and grading for roadways, parking areas, intersections, approaches, slope rounding, benching, waterways and ditches; removal of unsuitable material from the roadbed and beneath embankment areas; and excavating selected material found in the roadway as ordered by the Engineer for specific use in the improvement.

1.1.2 Borrow Excavation

Borrow excavation shall consist of the excavation and utilization of approved material required for the construction of embankments or for other portions of the work, and shall be obtained from approved sources.

1.1.3 General Excavation

General Excavation will cover open site excavation and other areas not classified as roadway and borrow excavation.

PART 2 – PRODUCTS (Not Applicable) PART 3 – EXECUTION 3.1 General

When there is evidence of discrepancies on the actual elevations and that shown on the Plans, a pre-construction survey referred to the datum plane used in the approved Plan shall be undertaken by the Contractor under the control of the Engineer to serve as basis for the computation of the actual volume of the excavated materials.

All excavations shall be finished to reasonably smooth and uniform surfaces. No materials shall be wasted without authority of the Engineer. Excavation operations shall be conducted so that material outside of the limits of slopes will not be disturbed. Prior to excavation, all necessary clearing and grubbing in that area shall have been performed in accordance with Item 100, "Clearing and Grubbing".

3.2 Conservation of Topsoil

Where provided for on the Plans, suitable topsoil encountered in excavation and on areas where embankment is to be placed shall be removed to such extent and such depth as the Engineer may direct. The removed topsoil shall be transported and deposited in storage piles at locations approved by the Engineer. The topsoil shall be completely removed to the required depth from any designated area prior to the beginning of regular excavation or embankment work in the area and shall be kept separate from other excavated materials for later use.

Bicol International Airport Development Project Part C - Earthwork Section VI- Technical Specification Excavation

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3.3 Utilization of Excavated Materials

All suitable material removed from the excavation shall be used in the formation of the embankment, subgrade, shoulders, slopes, bedding, and backfill for structures, and for other purposes shown on the Plans or as directed.

3.4 Prewatering

Excavation areas and borrow pits may be prewatered before excavating the material. When prewatering is used, the areas to be excavated shall be moistened to the full depth, from the surface to the bottom of the excavation. The water shall be controlled so that the excavated material will contain the proper moisture to permit compaction to the specified density with the use of standard compacting equipment. Prewatering shall be supplemented where necessary, truck watering units, to assure that the embankment material contains the proper moisture at the time of compaction.



The cost of excavation of material which is incorporated in the Works or in other areas of fill shall be deemed to be included in the Items of Work where the material is used.

Measurement of Unsuitable or Surplus Material shall be the net volume in its original position. For measurement purposes, surplus suitable material shall be calculated as the difference

between the net volume of suitable material required to be used in embankment corrected by applying a shrinkage factor or a swell factor in case of rock excavation, determined by laboratory tests to get its original volume measurement, and the net volume of suitable material from excavation in the original position. Separate pay items shall be provided for surplus common, unclassified and rock material.

The Contractor shall be deemed to have included in the contract unit prices all costs of obtaining

land for the disposal of unsuitable or surplus material.


The accepted quantities, measured as prescribed in Sub-item 4.1 above, shall be paid for at the contract unit price for each of the Pay Items listed below that is included in the Bill of Quantities which price and payment shall be full compensation for the removal and disposal of excavated materials including all labor, equipment, tools and incidentals necessary to complete the work prescribed in this Item.


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Bicol International Airport Development Project Part C - Earthwork Section VI- Technical Specification Structure Excavation

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ITEM 103 - STRUCTURE EXCAVATION PART 1 – GENERAL 1.1 Description This Item shall consist of the necessary excavation for foundations of culverts, and other

structures not otherwise provided for in the Specifications. Except as otherwise provided for pipe culverts, the backfilling of completed structures and the disposal of all excavated materials, shall be in accordance with these Specifications and in reasonably close conformity with the Plans or as established by the Engineer.

This Item shall include necessary diverting of live streams, bailing, pumping, draining, sheeting,

bracing, and the necessary construction of cribs and cofferdams, and furnishing the materials therefore, and the subsequent removal of cribs and cofferdams and the placing of all necessary backfill.

It shall also include the furnishing and placing of approved foundation fill materials to replace

unsuitable material encountered below the foundation elevation of structures. No allowance will be made for classification of different types of material encountered. PART 2 – PRODUCTS (Not Applicable) PART 3 – EXECUTION 3.1 Excavation a. General, all structure. Trenches or foundation pits for structures or structure footing shall be excavated to the

lines and grades or elevations shown on the Plans or as staked by the Engineer. They shall be of sufficient size to permit the placing of structures or structure footings of the full width and length shown. The elevations of the bottoms of footings, as shown on the Plans, shall be considered as approximate only and the Engineer may order, in writing, such changes in dimensions or elevations of footing as may be deemed necessary, to secure a satisfactory foundation.

Boulders, logs, and other objectionable materials encountered in excavation shall be

removed.

After each excavation is completed, the Contractor shall notify the Engineer to that effect and no footing, bedding material or pipe culvert shall be placed until the Engineer has approved the depth of excavation and the character of the foundation material.

b. Structures other than pipe culverts. All rock or other hard foundation materials shall be

cleaned of all loose materials, and cut to a firm surface, either level, steeped, or serrated as directed by the Engineer. All seams or crevices shall be cleaned and grouted. All loose and disintegrated rocks and thin strata be removed. When the footing is to rest on material other than rock, excavation to final grade shall not be made until just before the footing is to be placed. When the foundation material is soft or mucky or otherwise unsuitable, as determined by the Engineer, the Contractor shall remove the unsuitable material and backfill with approved granular material. This foundation fill shall be placed and compacted in adequate layers up to the foundation elevation.


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c. Pipe Culverts. The width of the pipe trench shall be sufficient to permit satisfactory

jointing of the pipe and thorough tamping of the bedding material under and around pipe.

Where a firm foundation is not encountered at the grade established, due to soft,

spongy, or other unstable soil, such unstable soil under the pipe and for a width of at least one diameter on each side of the pipe shall be removed to the depth directed by the Engineer and replaced with approved granular foundation fill material properly compacted to provide adequate support for the pipe, unless other special construction methods are called for on the Plans.

The foundation surface shall provide a firm foundation of uniform density throughout the

length of the culvert and, if directed by the Engineer, shall be cambered in the direction parallel to the pipe centerline.

Where pipe culverts are to be placed in trenches excavated in embankment, the

excavation of each trench shall be performed after the embankment has been constructed to a plane parallel to the proposed profile grade and to such height above the bottom of the pipe as shown on the Plans or directed by the Engineer.

3.2 Utilization of Excavated Materials All excavated materials, so far as suitable, shall be utilized as backfill or embankment. The

surplus material shall be disposed off in such a manner as not to obstruct the stream or otherwise impair the efficiency or appearance of the structure. No excavated material shall be deposited at any time so as to endanger the partly finished structure.

3.3 Cofferdams

Suitable and practically watertight cofferdams shall be used wherever water-bearing strata are

encountered above the elevation of the bottom of the excavation. If requested, the Contractor shall submit drawings showing his proposed methods of cofferdams construction.

Cofferdams or cribs for foundation construction shall, in general, be carried well below the

bottoms of the footings and shall be well braced and as nearly watertight as practicable. In general, the interior dimensions of cofferdams shall be such as to give sufficient clearance for the construction of forms and the inspection of their exteriors, and to permit pumping outside of the forms. Cofferdams or cribs which are tilted or moved laterally during the process of sinking shall be righted or enlarged so as to provide the necessary clearance.

When conditions are encountered which, as determined by the Engineer, render it impracticable

to dewater the foundation before placing the footing, the Engineer may require the construction of a concrete foundation seal of such dimensions as he may consider necessary, and of such thickness as to resist any possible uplift. The concrete for such seal shall be placed as shown on the Plans or directed by the Engineer. The foundation shall then be dewatered and the footing placed. When weighted cribs are employed and the mass is utilized to overcome partially the hydrostatic pressure acting against the bottom of the foundation seal, special anchorage such as dowels or keys shall be provided to transfer the entire mass of the crib to the foundation seal. When a foundation seal is placed under water, the cofferdams shall be vented or ported at low water level as directed.

Cofferdams shall be constructed so as to protect green concrete against damage from sudden

rising of the stream and to prevent damage to the foundation by erosion. No timber or bracing shall be left in cofferdams or cribs in such a way as to extend into substructure masonry, without written permission from the Engineer.


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Any pumping that may be permitted from the interior of any foundation enclosure shall be done

in such a manner as to preclude the possibility of any portion of the concrete materials being carried away. Any pumping required during the placing of concrete, or for a period of at least 24 hours thereafter, shall be done from a suitable sump located outside the concrete forms. Pumping to dewater a sealed cofferdam shall not commence until the seal has set sufficiency to withstand the hydrostatic pressure.

Unless otherwise provided, cofferdams or cribs, with all sheeting and bracing involved therewith,

shall be removed by the Contractor after the completion of the substructure. Removal shall be effected in such manner as not to disturb or mar finished masonry.

3.4 Backfill and Embankment for Structures Other than Pipe Culverts Excavated areas around structures shall be backfilled with free draining granular material

approved by the Engineer and placed in horizontal layers not over 150 mm (6 inches) in thickness, to the level of the original ground surface. Each layer shall be moistened or dried as required and thoroughly compacted with mechanical tampers.

In placing backfills or embankment, the material shall be placed simultaneously insofar as

possible to approximately the same elevation on both sides of an abutment, pier or wall. Backfill or embankment shall not be placed behind the walls of concrete culverts or abutments

or rigid frame structures until the top slab is placed and cured. Backfill and embankment behind abutment held at the top by the superstructure, and behind sidewalls of culverts, shall be carried up simultaneously behind opposite abutments or sidewalls.


The quantity of structural steel, structural concrete, reinforcing steel or other Contract Pay Items

shall constitute the completed and accepted structure which shall be measured for payment in the manner prescribed in the several items involved.


The quantities measured as provided in Sub-item 4.1, Method of Measurement shall be paid for

at the contract price for the several pay items which price and payment shall be full compensation for furnishing, preparing, fabricating, placing, curing and for all labor, equipment, tools and incidentals necessary to complete the Item. Such payment shall constitute full payment for the completed structure ready for use.


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Bicol International Airport Development Project Part C - Earthwork Section VI- Technical Specification Embankment

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ITEM 104 - EMBANKMENT PART 1 – GENERAL 1.1 Description This Item shall consist of the construction of embankment in accordance with this Specification

and in conformity with the lines, grades, and dimensions shown on Plans or established by the Engineer.

PART 2 – PRODUCTS Embankment shall be constructed of suitable materials, in consonance with the following

definitions: 2.1 Suitable Material Material which is acceptable in accordance with the Contract and which can be compacted in

the manner specified in this Item. It can be common material or rock. Selected Borrow, for topping - soil with such gradation that all particles will pass a sieve with

75 mm (3 inches) square openings and not more than 15 mass percent will pass the 0.075 mm (No. 200) sieve, as determined by AASHTO T 11. The material shall have a plasticity index of not more than 6 as determined by AASHTO T 90 and a liquid limit of not more than 30 as determined by AASHTO T 89.

2.2 Unsuitable Materials Material other than suitable material such as:

a. Materials containing detrimental quantities of organic materials, such as grass, roots and sewage.

b. Highly organic soils such as peat and muck. c. Clay with liquid limit exceeding 80 and/or plasticity index exceeding 55. d. Soils with a natural water content exceeding 100%. e. Soils with very low natural density, 800 kg/m or lower. f. Soils that can not be properly compacted as determined by the Engineer. PART 3 – EXECUTION 3.1 General Embankment construction shall consist of constructing site and roadway embankments,

including preparation of the areas upon which they are to be placed; the construction of dikes within or adjacent to the roadway; the placing and compacting of approved material where unsuitable material has been removed; and the placing and compacting of embankment material in holes, pits, and other depressions.

Embankments and backfills shall contain no muck, peat, sod, roots or other deleterious matter.

Rocks, broken concrete or other solid, bulky materials shall not be placed in embankment areas where piling is to be placed or driven.

Where provided on the Plans and Bill of Quantities the top portions of the roadbed in both cuts


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and embankments, as indicated, shall consist of selected borrow for topping from excavations. 3.2 Methods of Construction When there is evidence of discrepancies on the actual elevations and that shown on the Plans,

a preconstruction survey referred to the datum plane used in the approved Plan shall be undertaken by the Contractor under the control of the Engineer to serve as basis for the computation of the actual volume of the embankment materials.

When new embankment is to be constructed against existing embankments, or when embankment is built one-half width at a time, the existing slopes that are steeper than 3:1 when measured at right angles to the roadway shall be continuously benched over those areas as the work is brought up in layers. Benching will be subject to the Engineer's approval and shall be of sufficient width to permit operation of placement and compaction equipment. Each horizontal cut shall begin at the intersection of the original ground and the vertical sides of the previous cuts. Material thus excavated shall be placed and compacted along with the embankment material in accordance with the procedure described in this Section.

Unless shown otherwise on the Plans, where an embankment of less than 1.2 m (4 feet) below

subgrade is to be made, all sod and vegetable matter shall be removed from the surface upon which the embankment is to be placed, and the cleared surface shall be completely broken up by plowing, scarifying, or stepping to a minimum depth of 150 mm except as provided in Item 102, Sub-item 3.2, "Conservation of Topsoil". This area shall then be compacted as provided in Sub-item 3.3 of this Section. Sod not required to be removed shall be thoroughly disc harrowed or scarified before construction of embankment. Whenever a compacted road surface containing granular materials lies within 900 mm (36 inches) of the subgrade, such old road surface shall be scarified to a depth of at least 150 mm (6 inches) whenever directed by the Engineer. This scarified material shall then be compacted as provided in Sub-item 3.3 of this Section.

When shoulder excavation is specified, the roadway shoulders shall be excavated to the depth

and width shown on the Plans. The shoulder material shall be removed without disturbing the adjacent existing base course material, and all excess excavated materials shall be disposed of as provided in Sub-item 3.3 of Item 102. If necessary, the areas shall be compacted before being backfilled.

Roadway embankment in earth material shall be placed in horizontal layers not exceeding 200

mm (8 inches), loose measurement, and shall be compacted as specified before the next layer is placed. Effective spreading equipment shall be used on each lift to obtain uniform thickness prior to compacting. As the compaction of each layer progresses, continuous leveling and manipulating will be required to assure uniform density. Water shall be added or removed, if necessary, in order to obtain the required density. Removal of water shall be accomplished through aeration by plowing, blading, discing, or other methods satisfactory to the Engineer.

Where embankment is to be constructed across low swampy ground that will not support the

mass of trucks or other hauling equipment, the lower part of the fill may be constructed by dumping successive loads in a uniformly distributed layer of a thickness not greater than necessary to support the hauling equipment while placing subsequent layers.

When excavated material contains more than 25 mass percent of rock larger than 150 mm in

greatest diameter and cannot be placed in layers of the thickness prescribed without crushing, pulverizing or further breaking down the pieces resulting from excavation methods, such materials may be placed on the embankment in layers not exceeding in thickness the approximate average size of the larger rocks, but not greater than 600 mm (24 inches).

Each layer shall be leveled and smoothed with suitable leveling equipment and by distribution of spalls and finer fragments of earth. Lifts of material containing more than 25 mass percent of rock larger than 150 mm in greatest dimension shall not be constructed above an elevation 300 mm (12 inches) below the finished subgrade. The balance of the embankment shall be


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composed of suitable material smoothed and placed in layers not exceeding 200 mm (8 inches) in loose thickness and compacted as specified for embankments.

Dumping and rolling areas shall be kept separate, and no lifts shall be covered by another until

compaction complies with the requirements of Subsection 3.3 of this Section.

Hauling and leveling equipment shall be so routed and distributed over each layer of the fill in such a manner as to make use of compaction effort afforded thereby and to minimize rutting and uneven compaction.

3.3 Compaction 3.3.1 Compaction Trials

Before commencing the formation of embankments, the Contractor shall submit in writing to the Engineer for approval his proposals for the compaction of each type of fill material to be used in the Works. The proposals shall include the relationship between the types of compaction equipment, and the number of passes required and the method of adjusting moisture content. The Contractor shall carry out full scale compaction trials on areas not less than 6 m wide and 30 m long as required by the Engineer and using his proposed procedures or such amendments thereto as may be found necessary to satisfy the Engineer that all the specified requirements regarding compaction can be consistently achieved. Compaction trials with the main types of fill material to be used in the Works shall be completed before work with the corresponding materials will be allowed to commence. Throughout the periods when compaction of earthwork is in progress, the Contractor shall adhere to the compaction procedures found from compaction trials for each type of material being compacted, each type of compaction equipment employed and each degree of compaction specified.

3.3.2 Earth

The compaction requirement for the subgrade and fill materials shall be in accordance with the provisions specified under Civil Works Drawing No. CW-001. Acceptance of compaction may be based on adherence to an approved roller pattern developed as set forth in Item 106, "Compaction Equipment and Density Control Strips".

3.4 Protection of Roadbed Construction

During the construction of the roadway, the roadbed shall be maintained in such condition that it will be well drained at all times. Side ditches or gutters emptying from cuts to embankments or otherwise shall be so constructed as to avoid damage to embankment by erosion and saturation of water.

3.5 Protection of Structures

If embankment can be deposited on one side only of culvert headwalls, care shall be taken that the area immediately adjacent to the structure is not compacted to the extent that it will cause overturning of, or excessive pressure against the structure. When embankment is to be placed on both sides of a concrete wall or box type structure, operations shall be so conducted that the embankment is always at approximately the same elevation on both sides of the structure.

3.6 Rounding and Warping Slopes Rounding - Except in solid rock, the top and bottom of all slopes, including the slopes of

drainage ditches, shall be rounded as indicated on the Plans. A layer of earth overlaying rock shall be rounded above the rock as done in earth slopes.


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Warping - Adjustments in slopes shall be made to avoid injury in standing trees or marring of weathered rock, or to harmonize with existing landscape features, and the transition to such adjusted slopes shall be gradual. At intersections of cuts and fills, slopes shall be adjusted and warped to flow into each other or into the natural ground surfaces without noticeable break.

3.7 Finishing Roadbed and Slopes

After the roadbed has been substantially completed, the full width shall be conditioned by removing any soft or other unstable material that will not compact properly or serve the intended purpose. The resulting areas and all sections, holes or depressions shall be brought to grade with suitable selected material. Scarifying, blading, dragging, rolling, or other methods of works shall be performed or used as necessary to provide thoroughly compacted roadbed shaped to the grades and cross-sections shown on the Plans or as staked by the Engineer.

All earth slopes shall be left with roughened surfaces but shall be reasonably uniform, without any noticeable break, and in reasonably close conformity with the Plans or other surfaces indicated on the Plans or as staked by the Engineer, with no variations there from readily discernible as viewed from the road.

PART 4 – METHOD OF MEASUREMENT AND PAYMENT 4.1 Method of Measurement The quantity of embankment to be paid for shall be the volume of material compacted in place,

accepted by the Engineer and formed with material obtained from any source. Material from excavation per Item 102 which is used in embankment and accepted by the

Engineer will be paid under Embankment and such payment will be deemed to include the cost of excavating, hauling, stockpiling and all other costs incidental to the work.

Material for Selected Borrow topping will be measured and paid for under the same conditions

specified in the preceding paragraph.

4.2 Basis of Payment The accepted quantities, measured as prescribed in Sub-item 4.1, shall be paid for at the

Contract unit price for each of the Pay Items listed below that is included in the Bill of Quantities. The payment shall constitute full compensation for placing and compacting all materials including all labor, equipment, tools and incidentals necessary to complete the work prescribed in this Item.


*****

Bicol International Airport Development Project Part C - Earthwork Section VI- Technical Specification Subgrade Preparation

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ITEM 105 - SUBGRADE PREPARATION PART 1 - GENERAL 1.1 Description

This Item shall consist of the preparation of the subgrade for the support of overlying structural layers. It shall extend to full width of the roadway. Unless authorized by the Engineer, subgrade preparation shall not be done unless the Contractor is able to start immediately the construction of the pavement structure.

PART 2 – PRODUCTS 2.1 MATERIAL REQUIREMENTS

Unless otherwise stated in the Contract and except when the subgrade is in rock cut, all materials below subgrade level to a depth 150 mm or to such greater depth as may be specified shall meet the requirements of Item 104, Sub-item 2.1, Selected Borrow for Topping.

PART 3 – EXECUTION 3.1 Prior Works

Prior to commencing preparation of the subgrade, all culverts, cross drains, ducts and the like (including their fully compacted backfill), ditches, drains and drainage outlets shall be completed. Any work on the preparation of the subgrade shall not be started unless prior work herein described shall have been approved by the Engineer.

3.2 Subgrade in Common Excavation

Unless otherwise specified, all materials below subgrade level in earth cuts to a depth 150 mm or other shown on the Plans or as directed by the Engineer shall be excavated. The material, if suitable, shall be set aside for future use.

Where material has been removed from below subgrade level, the resulting surface shall be compacted to a depth of 150 mm and in accordance with the other requirements of Sub-item 3.3 of Item 104.

All materials immediately below subgrade level in earth cuts to a depth of 150 mm, or to such greater depth as may be specified, shall be compacted in accordance with the requirements of Sub-item 3.3 of Item 104.

3.3 Subgrade on Embankment

After the embankment has been completed, the full width shall be conditioned by removing any soft or other unsuitable material that will not compact properly. The resulting areas and all other low sections, holes, or depressions shall be brought to grade with suitable material. The entire shall then be shaped and compacted to the requirements of Sub-item 3.3 of Item 104. Scarifying, blading, dragging, rolling or other methods of work shall be performed or used as necessary to provide a thoroughly compacted roadbed shaped to the cross-section on the Plans.

3.4 Protection of Completed Work

The Contractor shall be required to protect and maintain at his own expense the entire work within the limits of his Contract in good condition satisfactory to the Engineer from the time he first started work until all work shall have been completed. Maintenance shall include repairing

Bicol International Airport Development Project Part C - Earthwork Section VI- Technical Specification Subgrade Preparation

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and recompacting ruts, soft spots and deteriorated sections of the subgrade caused by the traffic of the Contractor's vehicle/equipment or that of the public.


4.1 Method of Measurement 4.1.1 Measurement of Items for payment shall be provided only for:

1. The compaction of existing ground below subgrade level in cuts of common material as specified in Sub-item 3.3.

4.1.2 Payment for all work for the preparation of the subgrade, including shaping to the required

levels and tolerances, other than as specified above shall be deemed to be included in the Pay Item for Embankment.

4.2 Basis of Payment The accepted quantities, measured as prescribed in Sub-item 4.1 shall be paid for at the

appropriate contract unit price for Pay Item listed below that is included in the Bill of Quantities which price and payment shall be full compensation for the placing or removal and disposal of all materials including all labor, equipment, tools and incidentals necessary to complete the work prescribed in this Item.


*****

Bicol International Airport Development Project Part C - Earthwork Section VI- Technical Specification Compaction Equipment and Density Control Strips

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ITEM 106 - COMPACTION EQUIPMENT AND DENSITY CONTROL STRIPS PART 1 – GENERAL 1.1 Description When specified, this procedure will be used to determine density requirements of selected

embankments, subgrade, bases, and bituminous concrete. The procedure will consist of control strip construction to establish target densities for the specified course plus use of sand-cone method of density testing equipment to determine in place densities obtained during the construction process.

PART 2 – PRODUCTS (Not Applicable) PART 3 – EXECUTION 3.1 Compaction Equipment

Compaction equipment shall be capable of obtaining compaction requirements without detrimentally affecting the compacted material. The equipment shall be modern, efficient compacting units approved by the Engineer. The compacting units may be of any type, provided they are capable of compacting each lift of material as specified and meet the minimum requirements as contained herein. Minimum requirements for rollers are as follows:

a. Sheepsfoot, tamping or grid rollers shall be capable of exerting a force of 45 Newton

per millimeter (250 pounds per inch) of length of roller drum.

b. Steel-wheel rollers other than vibratory shall be capable of exerting a force of not less than 45 Newton per millimeter of width of the compression roll or rolls.

c. Vibratory steel-wheel rollers shall have a minimum mass of 6 tonnes. The compactor

shall be equipped with amplitude and frequency controls and specifically designed to compact the material on which it is used.

d. Pneumatic-tire rollers shall have smooth tread of equal size that will provide a uniform

compacting pressure for the full width of the roller and capable of exerting a ground pressure of at least 550 kPa (80 pounds per square inch).

e. Heavier compacting units may be required to achieve the specified density of the

embankment. 3.2 Construction of Control Strips and Determination of Target Density

To determine target density, a control strip shall be compacted at the beginning of work on each course of material to be compacted. Each control strip, constructed to acceptable density and surface tolerances shall remain in place and become a section of the completed roadway. Unacceptable control strip shall be corrected or removed and replaced at the Contractor's expense. A control strip shall have an area of approximately 335 square meters and shall be of the same depth specified for the construction of the course which it represents.

The materials used in the construction of the control strip shall conform to the specification requirements. They shall be furnished from the same source and shall be on the same type to be used in the remainder of the course represented by the control strip. The underlying grade

Bicol International Airport Development Project Part C - Earthwork Section VI- Technical Specification Compaction Equipment and Density Control Strips

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or pavement structure upon which a control strip is to be constructed shall have the prior approval of the Engineer.

The equipment used in the construction of the control strip shall be approved by the Engineer and shall be of the same type and mass to be used on the remainder of the course represented by the control strip.

Compaction of controls strips shall commence immediately after the course has been placed to the specified thickness, and shall be continuous and uniform over the entire surface. Compaction of the control strip shall be continued until no discernible increase in density can be obtained by additional compactive effort.

Upon completion of the compaction, the mean density of the control strip will be determined by averaging the results of ten in place density tests taken at randomly selected sites within the control strip. The mean density of the control strip shall be the target density for the remainder of the course which it represents.

If the mean density of the control strip is less than 98 percent of the density of laboratory compacted specimens as determined by testing procedures appropriate for the material being placed, the Engineer may order the construction of another control strip.

A new control strip may also be ordered by the Engineer or requested by the Contractor when:

a. A change in the material or job-mix formula is made.

b. Ten days of production have been accepted without construction of a new control strip.

c. There is reason to believe that a control strip density is not representative of the material being placed.



No measurement for payment will be made for this item.


Unless otherwise provided, the cost of constructing the control strip will be considered incidental to the cost of the work item for which a control strip is required. Payment for the work item shall be deemed to include compensation for performing the work therein specified and the furnishing of all materials, labors, tools, equipment and incidentals necessary to construct the density control strip. No payment will be made for any material used in the construction of unacceptable control strip.


*****

PART F- BRIDGE CONSTRUCTION

Bicol International Airport Development Project Part F- Bridge Construction Section VI- Technical Specification Reinforcing Steel

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ITEM 404 - REINFORCING STEEL PART 1 – GENERAL 1.1 Description This Item shall consist of furnishing, bending, fabricating and placing of steel reinforcement of

the type, size, shape and grade required in accordance with this Specification and in conformity with the requirements shown on the Plans or as directed by the Engineer.

PART 2 – PRODUCTS 2.1 Material Requirements a. Reinforcing steel shall be conform to the requirement of AASHTO M31 (ASTM A 615)

and AASHTO M42.

b. Welded Wire Fabric for concrete walks shall conform to Section AASHTO M 55 (ASTM A 185), wire sizes and spacing as shown on the drawings.

PART 3 – EXECUTION 3.1 Order Lists

Before materials are ordered, all order lists and bending diagrams shall be furnished by the Contractor, for approval of the Engineer. The approval of order lists and bending by the Engineer shall in no way relieve the Contractor of responsibility for the correctness of such lists and diagrams. Any expense incident to the revisions to make them furnished in accordance with such lists and diagrams to make them comply with the Plans shall be borne by the Contractor.

3.2 Protection of Material

Steel reinforcement shall be stored above the surface of the ground upon platforms, skids, or other supports and shall be protected as far as practicable from mechanical injury and surface deterioration caused by exposure to conditions producing rust. When placed in the work, reinforcement shall be free from dirt, detrimental rust, loose scale, paint, grease, oil, or other foreign materials. Reinforcement shall be free form injurious defects such as cracks and laminations. Rust, surface seams, surface irregularities or mill scale will not be cause for rejection, provided the minimum dimensions, cross-sectional area and tensile properties of a hand wire brushed specimen meets the physical requirements for the size and grade of steel specified.

3.3 Bending

All reinforcing bars requiring bending shall be cold-bent to the shapes shown on the Plans or required by the Engineer. Bars shall be bent around a circular pin having the following diameters (D) in relation to the diameter of the bar (d):

Nominal diameter Pin (D) d, mm 10 to 20 6d 25 to 28 8d 32 and greater 10d


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Bends and hooks in stirrups or ties may be bent to the diameter in the principal bar enclosed therein.

3.4 Placing and Fastening

All steel reinforcement shall be accurately placed in the position shown on the Plans or required by the Engineer and firmly held there during the placing and setting of the concrete. Bars shall be tied at all intersections except where spacing is less than 300 mm in each direction, in which case, alternate intersections shall be tied. Ties shall be fastened on the inside.

Distance from the forms shall be maintained by means of stays, blocks, ties, hangers, or other

approved supports, so that it does not vary from the position indicated on the Plans by more than 6 mm. Blocks for holding reinforcement from contact with the forms shall be precast mortar blocks of approved shapes and dimensions. Layers of bars shall be separated by precast mortar blocks or by other equally suitable devices. The use of pebbles, pieces of broken stone or brick, metal pipe and wooden blocks shall not be permitted. Unless otherwise shown on the Plans or required by the Engineer, the minimum distance between bars shall be 40 mm. Reinforcement in any member shall be placed and concrete begins. Concrete placed in violation of this provision may be rejected and removal may be required. If fabric reinforcement is shipped in rolls, it shall be straightened before being placed. Bundled bars shall be tied together at not more than 1.8 m intervals.

3.5 Splicing

All reinforcement shall be furnished in the full lengths indicated on the Plans. Splicing of bars, except where shown on the Plans, will not be permitted without the written approval of the Engineer. Splices shall be staggered as far as possible and with a minimum separation of not less than 40 bar diameter. Not more than one-third of the bars may be spliced in the same cross- section, except where shown on the Plans.

Unless otherwise shown on the Plans, bars shall be lapped a minimum distance of: --------------------------------------------------------------------------- Splice Type Grade 40 Grade 60 But not less than min. lap min. lap --------------------------------------------------------------------------- Tension 24 bar dia 36 bar dia 300 mm Compression 20 bar dia 24 bar dia 300 mm --------------------------------------------------------------------------- In lapped splices, the bars shall be placed in contact and wired together. Lapped splices will not

be permitted at locations where the concrete sections is sufficient to provide minimum clear distance of one and one-third the maximum size of aggregate between the splice and the nearest adjacent bar. Welding of reinforcing steel shall be done only if detailed on the Plans or if authorized by the Engineer in writing. Spiral reinforcement shall be spliced by lapping at least one and a half turns or by butt welding otherwise shown on the Plans.

3.6 Lapping of Bar Mat

Sheets of mesh or bar mat reinforcement shall overlap each other sufficiently to maintain a uniform strength and shall be securely fastened at the ends and edges. The overlap shall not be less than one mesh in width.


The quantity of reinforcing steel to be paid for will be the final quantity placed and accepted in


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the completed structure. No allowance will be made for tie-wires, separators, wire chairs and other material used in

fastening the reinforcing steel in place. If bars are substituted upon the Contractor's request and approved by the Engineer and as a result thereof more steel is used than specified, only the mass specified shall be measured for payment.

No measurement or payment will be made for splices added by the Contractor unless directed

or approved by the Engineer. When there is no item for reinforcing steel in the Bill of Quantities, costs will be considered as

incidental to the other items in the Bill of Quantities


Payment will be made in accordance with the Bill of Quantities. *****

Bicol International Airport Development Project Part F- Bridge Construction Section VI- Technical Specifications Structural Concrete

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ITEM 405 - STRUCTURAL CONCRETE PART 1 – GENERAL 1.1 Scope This Item shall consist of furnishing, placing and finishing concrete in all structures in

accordance with this specification and conforming to the lines, grades, and dimensions shown on the Plans. Concrete shall consist of a mixture of Portland cement, fine aggregate, coarse aggregate, admixtures when specified, and water mixed in the proportions specified or approved by the Engineer.

1.2 Classes and Uses of Concrete Five classes of concrete are provided for in this Section, namely: A, B, C, P and Seal. Each

class shall be used in that part of the structure as called for on the Plans. The classes of concrete will generally be used as follows: Class A - All superstructures and heavily reinforced substructures. The important parts of the

structure included are slabs, columns, reinforced abutments, retaining walls, manhole, headwall/wingwall, and reinforced footings.

Class B - Footings, pedestals, pipe bedding and gravity walls, unreinforced or with only a small

amount of reinforcement. Class C - Thin reinforced sections, railings, and for filler in steel grid members. Class P - Prestressed deposited structures and members. Seal - Concrete deposited in water. PART 2 – PRODUCTS 2.1 Portland Cement

It shall conform to the applicable requirements of AASHTO M85 (ASTM C 150). Only Type I Portland Cement shall be used unless otherwise specified or approved by the Engineer. Different brands or the same brands from different mills shall not be mixed nor shall they be used alternately unless the mix is approved by the Engineer.

Cement which for any reason, has become partially set or which contains lumps of caked

cement will be rejected. Cement salvaged from discarded or used bags shall not be used. Samples of cement shall be obtained in accordance with AASHTO T 1217. 2.2 Fine Aggregates

It shall be of natural sand, stone screenings or other inert materials with similar characteristics, or combination thereof, having hard, strong and durable particles approved by the Engineer. Fine aggregate from different sources of supply shall not be mixed or stored in the same pile nor used alternately in the same class of concrete without the approval of the Engineer.

It shall not contain more than three (3) mass percent of material passing the 0.075 mm (No. 200

sieve) by washing nor more than one (1) mass percent each of clay lumps or shale. The use of beach sand will not be allowed without the approval of the Engineer.


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If the fine aggregate is subjected to five (5) cycles of the sodium sulfate soundness test, the

weighted loss shall not exceed 10 mass percent.

The fine aggregate shall be free from injurious amounts of organic impurities. If subjected to the colorimetric test for organic impurities, a color darker than the standard is produced, it shall be rejected. However, when tested for the effect of organic impurities of strength of mortar by AASHTO T 71, the fine aggregate may be used if the relative strength at 7 and 28 days is not less than 95 mass percent.

The fine aggregate shall be well-graded from coarse to fine and shall conform to Table 405.1. Table 405.1 - Grading Requirements for Fine Aggregates.

Sieve Designation Mass Percent Passing

9.5 mm (3/8 in) 4.75 mm (No, 4) 1.18 mm (No.16) 0.300 mm (No.50) 0.150 mm (No.100)

100 95-100 45-80 5-30 0-10

2.3 Coarse Aggregates

It shall consist of crushed stone, gravel, blast furnace slag, or other approved inert materials of similar characteristics, or combinations thereof, having hard, strong, durable pieces and free from any adherent coatings.

It shall contain not more than one (1) mass percent of material passing the 0.075 mm (No.200)

sieve, not more than 0.25 mass percent of clay lumps, nor more than 3.5 mass percent of soft fragments.

If the coarse aggregate is subjected to five (5) cycles of the sodium sulfate soundness test, the

weighted loss shall not exceed 12 mass percent. It shall have a mass percent of wear not exceeding 40 when tested by AASHTO T 96.

If slag is used, its density shall not be less than 1120 kg/m3 (970 lb/cu. ft.). The gradation of the aggregate shall conform to Table 405.2.

Only one grading specification shall be used from any one source. Table 405.2 - Grading Requirements for Coarse Aggregate

Sieve Designation Mass Percent Passing for

Standard mm

Alternate US Standard

Class A

Class B

Class C

Class P

Class Seal

63 50

37.5 25

19.0 12.5 9.5 4.75

2 1/2" 2"

1 1/2" 1" ¾" ½" 3/8"

No. 4

100 95-100

- 35-70

- 10-30

- 0-5

- 100

95-100 -

35-70 -

10-30 0-5

- -

100 95-100

- 25-60

- 0-10*

- - -

100 90-100

- 20-55 0-10*

- - - -

100 90-100 40-70 0-15*

The measured cement content shall be within plus (+) or minus (-) 2 mass percent of


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the design cement content. 2.4 Water Water used in mixing, curing or other designated applications shall be reasonably clean and free

of oil, salt, grass or other substances injurious to the finished product. Water which is drinkable may be used without test. Where the source of water is shallow, the intake shall be so enclosed as to exclude silt, mud, grass or other foreign materials.

2.5 Reinforcing Steel

It shall conform to the requirements of Item 405. Dowel and tie bars shall conform to the requirements of AASHTO T 31 or M 42, except that rail steel shall not be used for tie bars that are to be bent and restraightened during construction. Tie bars shall be deformed bars. Dowels shall be plain round bars. Before delivery to the Site, one half of the length of each dowel shall be painted with one coat of approved lead or tar paint.

The sleeves of dowels shall be metal of approved design to cover 50 mm (2 inches). plus or

minus 5 mm (1/4 inch) of the dowel, with a closed end, and with a suitable stop to hold the end of the sleeve at least 25 mm (1 inch) from the end of the dowel. Sleeves shall be of such design that they do not collapse during construction.

2.6 Admixtures Air-entraining admixtures shall conform to the requirements of AASHTO T 154.

Chemical admixtures, if specified or permitted, shall conform to the requirements of AASHTO T 194.

2.7 Curing Concrete

Burlap cloth shall conform to the requirements set forth in AASHTO M 182. Sheet materials for curing concrete shall conform to the requirements set forth in AASHTO M 171.

Membrane curing shall consist of sealing the pavement surface with a uniform application of

non-bituminous pigmented liquid compound conforming to the requirements of AASHTO M148. 2.8 Expansion Joint Materials Expansion joint materials shall be: a. Preformed Sponge Rubber and Cork, conforming to AASHTO M 153. b. Hot – Poured Elastic Type, conforming to AASHTO M 173. c. Preformed Fillers, conforming to AASHTO M 213. 2.9 Elastomeric Compression Joint Seals These shall conform to AASHTO M 220. 2.10 Elastomeric Bearing Pads These shall conform to AASHTO M 251.


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2.11 Storage of Cement and Aggregates

All cement shall be stored, immediately upon delivery at the Site, in weatherproof building which will protect the cement from dampness. The floor shall be raised from the ground. The buildings shall be placed in locations approved by the Engineer. Provisions for storage shall be ample, and the shipments of cement as received shall be separately stored in such a manner as to allow the earliest deliveries to be used first and to provide easy access for identification and inspection of each shipment. Storage buildings shall have sampling at least twelve (12) days before the cement is to be used. Bulk cement, if used, shall be transferred to elevated air tight and weatherproof bins. Stored cement shall meet the test requirements at any time after shortage when retest is ordered by the Engineer. At the times of use, all cement shall be free-flowing and free of lumps.

The handling and storing of concrete aggregates shall be such as to prevent segregation or the

inclusion of foreign materials. The Engineer may require that aggregates be stored on separate platforms at satisfactory locations.

In order to secure greater uniformity of concrete mix, the Engineer may require that the coarse

aggregate be separated into two or more sizes. Different sizes of aggregates shall be stored in separate bins or in separate stock piles sufficiently remote from each other to prevent the material at the edges of the piles from becoming intermixed.

2.12 Sampling an Testing of Structural Concrete As work progresses, at least one (1) sample consisting of three (3) concrete cylinder test

specimens, 150 x 300 mm (6 x 12 inches), shall be taken from each seventy five (75) cubic meters of each class of concrete or fraction thereof placed each day.

Compliance with the requirements of this Section shall be determined in accordance with the

following standard methods of AASHTO: Sampling of fresh concrete T 141 Weight per cubic meter and air content (gravimetric) of concrete T 121 Sieve analysis of fine and coarse aggregates T 27 Slump of Portland cement concrete T 119 Specific gravity and absorption of fine aggregate T 84 Tests for strength shall be made in accordance with the following: Making and curing concrete compressive and flexural tests specimens in the field T 23 Compressive strength of molded concrete cylinders T 22


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PART 3 – EXECUTION 3.1 Proportioning and Strength of Structural Concrete The concrete materials shall be proportioned in accordance with the requirements for each

class of concrete as specified in Table 405.3, using the absolute volume method as outlined in the American Concrete Institute (ACI) Standard 211.1, "Recommended Practice for Selecting Proportions for Normal and Heavyweight Concrete". Other methods of proportioning may be employed in the mix design with prior approval of the Engineer. The mix shall either be designed or approved by the Engineer. A change in the source of materials during the progress of work may necessitate a new mix design.

The strength requirements for each class of concrete shall be as specified in Table 405.3. Table 405.3 Composition and Strength of Concrete for use in Structures.

Classes of Concrete

Minimum Cement Content per m3

kg (bag**)

Maximum Water/ Cement Ratio

kg/kg

Consistency Range in Slump mm (inch)

Designated Size of Coarse Aggregate Square Opening Std. mm

Minimum Compressive Strength of 150x 300 mm concrete cylinder specimen at 28 days, MN/m2(psi)

A

B

C

P

Seal

360 (9 bags) 320 (8 bags) 380 (9.5 bags) 440 (11 bags) 380 (9.5 bags)

0.53

0.58

0.55

0.49

0.58

50-100 (2-4)

50-100 (2-4)

50-100 (2-4)

100 max. (4 max.)

100-200

(4-8)

37.5-4.75 (1 1/2"-No. 4) 50-4.75 (2"-No.4) 12.5-4.75 (1/2"-No.4) 19.0-4.75 (3/4"-No.4) 25-4.75 (1"-No.4)

20.7 (3000)

16.5

(2400)

20.7 (3000)

37.7

(5000)

20.7 (3000)

** Based on 40kg/bag 3.2 Consistency

Concrete shall have a consistency such that it will be workable in the required position. It shall be of a consistency that it will flow around reinforcing steel but individual particles of the coarse aggregate when isolated shall show on coating of mortar containing its proportionate amount of sand. The consistency of concrete shall be gauged by the ability of the requirement to properly place it and not by the difficulty in mixing and transporting. The quantity of mixing water shall be determined by the Engineer and shall not be varied without his consent. Concrete as dry as it is practical to place with the equipment specified shall be used.


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3.3 Batching Measuring and batching of materials shall be done at a batching plant. a. Portland Cement

Either sacked or bulk cement may be used. No fraction of a sack of cement shall be used in a batch of concrete unless the cement is weighed.

All bulk cement shall be weighed on an approved weighing device. The bulk cement

weighing hopper shall be properly sealed and vented to preclude dusting operation. The discharge chute shall not be suspended from the weighing hopper and shall be so arranged that cement will neither be lodged in it nor leak from it.

Accuracy of batching shall be within plus (+) or minus (-) 1 mass percent. b. Water

Water may be measured either by volume or by weight. The accuracy of measuring the water shall be within a range of error of not more than 1 percent.

c. Aggregates

All aggregates whether produced or handled by hydraulic methods or washed shall be stockpiled or binned for draining for at least 12 hours prior to batching. Rail shipment requiring more than 12 hours will be accepted as adequate binning only if the car bodies permit free drainage. If the aggregates contain high or non-uniform moisture content, storage or stockpile period in excess of 12 hours may be required by the Engineer.

Batching shall be so conducted as to result in a 2 mass percent maximum tolerance

for the required material. d. Bin and Scales

The batching plant shall include separate bins for bulk cement, fine aggregate and for each size of aggregate, a weighing hopper, and scales capable of determining accurately the mass of each component of the batch.

Scales shall be accurate to one-half (0.5) percent throughout the range used. e. Batching

When batches are hauled to the mixer, bulk cement shall be transported either in waterproofs compartments or between the fine and coarse aggregates. When cement is placed in contact with moist aggregates, batches will be rejected unless mixed within 1 1/2 hours of such contact. Sacked cement may be transported on top of the aggregates.

Batches shall be delivered to the mixer separate and intact. Each batch shall be

dumped cleanly into the mixer without loss, and, when more than one batch is carried on the truck, without spilling of the material from one batch compartment into another.

f. Admixture

The Contractor shall follow an approved procedure for adding the specified amount of


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admixture to each batch and will be responsible for its uniform operation during the progress of the work. He shall provide separate scales for the admixture which are to be proportioned by weight, and accurate measures for those to be proportioned by volume. Admixtures shall be measured into the mixer with an accuracy of plus or minus three (3) percent.

The use of calcium chloride as an admixture will not be permitted. 3.4 Mixing and Delivery

Concrete may be mixed at the site of construction, at a central point or by a combination of central point and truck mixing or by a combination of central point mixing and truck agitating. Mixing and delivery of concrete shall be in accordance with the appropriate requirements of AASHTO M 157 excepts as modified in the following paragraphs of this section, for truck mixing or a combination of central point and truck mixing or truck agitating. Delivery of concrete shall be regulated so that placing is at a continuous rate unless delayed by the placing operations. The intervals between delivery of batches shall not be so great as to allow the concrete in place to harden partially, and in no case shall such an interval exceed 30 minutes.

When volumetric measurements are authorized, the weight propositions shall be converted to

equivalent volumetric proportions. In such cases, suitable allowance shall be made for variations in the moisture condition of the aggregates, including the bulking effect in the fine aggregate. Batching and mixing shall be in accordance with ASTM C 685, Section 6 through 9.

Retempering concrete will not be permitted. Admixtures for increasing the workability, for

retarding the set, or for accelerating the set or improving the pumping characteristics of the concrete will be permitted only when specifically provided in the Contract, or authorized in writing by the Engineer.

a. Mixing Concrete: General

Concrete shall be thoroughly mixed in a mixer of an approved size and type that will insure a uniform distribution of the materials throughout the mass. All concrete shall be mixed in mechanically operated mixers. Mixing plant and equipment for transporting and placing concrete shall be arranged with an ample auxiliary installation to provide a minimum supply of concrete in case of breakdown of machinery or in case the normal supply of concrete is disrupted. The auxiliary supply of concrete shall be sufficient to complete the casting of a section up to a construction joint that will meet the approval of the Engineer.

b. Mixing Concrete at Site

Concrete mixers may be of the revolving drum or the revolving blade type and the mixing drum or blades shall be operated uniform at the mixing speed recommended by the manufacturer. The pick-up and throw-over blades of mixers shall be restored or replaced when any part or section is worn 20 mm or more below the original height of the manufacturer's design. Mixers and agitators which have an accumulation of hard concrete or mortar shall not be used.

c. Mixing Concrete at Central Plant Mixing at central plant shall conform to the requirements for mixing at the site. d. Mixing Concrete in Truck Truck mixers, unless otherwise authorized by the Engineer, shall be of the revolving


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drum type, watertight, and so constructed that the concrete can be mixed to insure a uniform distribution of materials throughout the mass. All solid materials for the concrete shall be accurately measured and charged into the drum at the proportioning plant. Except as subsequently provided, the truck mixer shall be equipped with a device by which the quantity of water added can be readily verified. The mixing water may be added directly to the batch, in which case a tank is not required. Truck mixers may be required to be provided with a means of which the mixing time can be readily verified by the Engineer.


4.1 Methods of Measurement

The quantity of structural concrete to be paid for will be the final quantity placed and accepted

in the completed structures. No deduction will be made for the volume occupied by pipe less than 100 mm (4 inches) in diameter or by reinforcing steel, anchors, conduits, weep holes or expansion joint materials.



*****

PART H – MISCELLANEOUS STRUCTURES

Bicol International Airport Development Project Part H – Miscellaneous Structures Section VI- Technical Specifications Security Fence and Gates

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ITEM 604 – SECURITY FENCE AND GATES PART 1 – GENERAL 1.1 Description

This Item shall consist of furnishing and constructing posts and chain link fences in accordance with the details, and at the locations, shown on the Plans, or as required by the Engineer.

This Item shall consist also of constructing concrete hollow block wall fences in accordance with the details, and at the locations, shown on the Plans, or as required by the Engineer.

1.2 Submittals

Before materials for security fence and gates are ordered, the Contractor shall submit to the Engineer complete shop drawings including details for approval.

PART 2 – PRODUCTS 2.1 Material Requirements 2.1.1 Chain Link Fence

Chain link fence fabric shall be fabricated from 8 gauge galvanized conforming to AASHTO M 181 and shall be of the type shown on the Plans. Before ordering the chain link fence fabric, the Contractor shall submit a sample of the material to the Engineer for testing and for approval.

2.1.2 Concrete Pedestal and Foundation

Concrete posts shall be made of Class A concrete in accordance with Item 405, Structural Concrete.

2.1.3 Steel Post and Railings

Steel posts shall be of the sections and length as specified or as shown on the Plans. The posts including railings shall be G.I. pipe galvanized, 50 mm dia., Schedule 40.

2.1.4 Steel Reinforcement

Steel reinforcement for concrete foundation and pedestal shall be deformed steel bars conforming to the provisions of Item 404, Reinforcing Steel.

Fabricate steel post and frames to design, dimension and details shown. Provide members in sizes and profiles indicated. The post and steel frames shall be welded at the joints. Finish exposed weld surface smooth and flush and blended to match adjoining surface.

2.1.5 Hardwares

Nuts, bolts, washers and other associated hardware shall be galvanized after fabrication as specified as ASTM 153.


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2.1.6 CHB Wall Fence

a. Concrete Hollow Blocks

Concrete Hollow Blocks shall conform to the requirements specified in the Philippine National Standards PNS 16:1984 Specifications for Concrete Hollow Blocks of the Product Standard Agency of the Ministry of Trade and Industry and now the Department of Trade and Industry.

b. Reinforcing Steel

Reinforcing Steel for vertical and horizontal reinforcement of Concrete Hollow Blocks (CHB) including reinforcement for column on footing, column and wall footing shall conform to the following: Deformed Billet-Steel Bars AASHTO M 31 (ASTM A 615) for Concrete Reinforcement

c. Mortar and Grout

Composition of Mortar shall be in accordance with the following: Unless otherwise indicated on the Plans, masonry mortar shall be composed of one part Portland Cement or air-entraining Portland Cement and two parts fine aggregate by volume to which hydrated lime has been added in an amount equal to ten (10) mass percent of the cement. In lieu of air-entraining cement, Portland cement may be used with an air-entraining admixture in accordance with the applicable provisions of Item 405. For masonry walls not exceeding 1.8 m (6 feet) in height, a mortar composed of one part masonry cement and two parts fine aggregate by volume maybe substituted for the above mixture of Portland Cement, lime and fine aggregate. For other construction, masonry cement may be used if and as shown on the Plans. Materials for mortar shall be in accordance with the following:

Either Type I or Type IA air-entraining Portland Cement, conforming to AASHTO M 85 may be used, except that when the contract contains an item for concrete under Item 405, the Contractor may use the same type as is used for that work. Masonry cement shall conform to the requirements of AASHTO M 150 - 74 (ASTM C 91). Fine aggregate shall conform to the requirements of AASHTO M 45 (ASTM C 144). Hydrated lime shall meet the requirements for Residue, Popping and Pitting, and Water retention shown for Type N lime in Section 701.3 (ASTM C 207). Water shall conform to the requirements of Item 714, Water. Air-entraining agents shall conform to the requirements of Section 708.2 AASHTO M 154 (ASTM C 260).

d. Concrete Footings and Columns

The materials for concrete footings and columns shall meet the requirements of Class B Concrete and Class A respectively of Item 405, “Structural Concrete”. The column shall be cast to the length shown on the Plans and shall have a smooth surface finish.


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PART 3 – EXECUTION 3.1 Construction Requirements

Prior to construction, the Contractor shall perform such clearing and grubbing as may be necessary to construct the fence to the required grade and alignment. Fence shall generally follow the contour of the ground. Grading shall be performed where necessary to provide a neat appearance.

3.2 Gates

Gates shall be constructed as shown on the Plans. 3.3 Chain Link Fence

a. Excavation and Backfilling

Trench for the wall footing shall be excavated to the required depth to the bottom of the concrete foundation as shown on Plans.

Backfilling shall be carried out by using suitable materials approved by the Engineer and shall be compacted in layers of not exceeding 150 mm in depth. Surplus excavated material shall be disposed by the Contractor as directed by the Engineer.

b. Placing of Concrete

The concrete for footings shall be placed on the excavation against the soil without forming.

c. Erection of Posts

The posts shall be erected vertically in position inside the formwork of the pedestal prior to the placing of the concrete and shall be adequately supported by bracing to protect movement of the post during the placing and setting of concrete. The posts shall be located at the position shown on the Plans.

d. Reinforcing Steel

Steel reinforcement shall be secured in place before the concrete is placed.

e. Installation of Chain Link Fence Fabric

The chain link fence fabric shall be set to line and elevation and pulled taut between each post before spot welding, or other method of fixing is carried out, where splicing of the fence fabric is necessary or at joints. The lapping of the chain link fence fabric shall be for a minimum of 100 mm and shall occur only at the post. No horizontal splicing will be permitted. The fence fabric shall be fixed to the posts as shown on the Plans. Any surface protection layer damaged during welding and/or construction shall be restored properly.

3.4 CHB Wall Fence

a. Excavation and Backfilling

Excavation for footing shall be made to the required lines, depth and width as shown on the Plans.


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Backfilling shall be carried out using suitable materials approved by the Engineer and shall be compacted in layers not exceeding 150 mm in depth. The Contractor, as directed by the Engineer, shall dispose all surplus excavated material.

b. Placing of Concrete

The concrete for footings shall be placed on the excavation against the soil without forming.

Prior to the placing of concrete for column, the formworks shall be adequately supported by bracing to prevent movement to the column during the placing and setting of concrete. The column shall be erected to the height and location shown on the Plans or as ordered by the Engineer.

Steel reinforcement shall be secured in place before the concrete is placed.

c. Laying Masonry Units

(1) Wet Masonry Units: Do not wet concrete masonry units. Do not lay units having a film of water on the surface.

(2) Placing Units: Lay hollow masonry units so as to preserve the vertical

continuity of cells filled with grout. The minimum clear horizontal dimensions of vertical cores shall be 50 mm by 75 mm. Masonry bond units at corners. Anchor intersections by reinforcing bars as indicated. Adjust each unit to its final position while mortar is still soft and plastic. If any unit is disturbed after mortar has stiffened, remove and relay in fresh mortar. Keep chases, raked out joints, and spaces to be grouted, free from mortar and other debris.

(3) Bond Pattern: Lay masonry units in running bond.

(4) Cutting and Fitting: Wherever possible, use full units of the proper size in lieu

of cut units. Use power masonry saws for cutting and fitting. Concrete-masonry units shall be wet cut. Make cut edges clean, true and sharp. Make openings carefully so that wall plates, cover plates or escutcheons required by the installation will completely conceal the openings and will be aligned at the bottom with the masonry joints. Cut webs of hollow masonry units to the minimum required for proper installation. Provide reinforced masonry lintels, above openings over 300 mm wide for pipes, ducts and cable trays unless steel sleeves are used.

(5) Mortar Joints: Spread bed joints with mortar for the full thickness of the face

shells. Where only cells containing reinforcement are to be grouted, spread cross webs around such cell with mortar to prevent leakage of grout. Butter head joints for full thickness of the face shell and place the units. Avoid fins of mortar that protrude into cells to be grouted.

(6) Jointing: Tool joints when the mortar is thumbprint hard. Tool horizontal joints

first. Brush joints to remove loose and excess mortar. Mortar joints shall be finished, as follows:

Tooled Joints: Tool joints in exposed exterior and interior masonry surfaces slightly concave. Use a jointer of sufficient length to obtain a straight and true mortar joints.


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(7) Joint Width: 9 mm wide.

(8) Surface Finish: A plaster coat of mortar shall be applied to the outer and inner surface of concrete hollow blocks. Such plaster coat shall be of mortar of the same material and proportions as that used in laying the blocks and shall not be less than 12.5 mm (1/2 inch) thick. Before applying a plaster coat to the block surface, the block shall be thoroughly wetted with water and the surface allowed to dry sufficiently to provide for proper bonding of the plaster coat

d. Placing Reinforcing Steel

Prior to placing grout, clean, reinforcement of loose, flaky rust, scale, grease, mortar, grout, or other coating which might destroy or reduce its bond with the grout. Details of reinforcement shall be in conformance with ACI 315. Do not bend or straighten reinforcing in a manner a injurious to the steel. Do not use bars with kinks or bends not shown on the drawings. Placement of reinforcement shall be inspected and approved prior to placing grout.

(1) Positioning Bars: Position vertical bars accurately at the centerline of the

wall. Maintain a minimum clearance between the bars and masonry units of 12 mm and between parallel bars of one diameter of the reinforcement. Hold vertical reinforcing in place using metal support, centering clips, spaces, ties or caging devices located near the ends of each bar and at intermediate intervals of not more than 192 diameters of the reinforcement.

(2) Splices: Locate splices only as indicated. Stagger splices in adjacent bars at

least 600 mm. Lap bars a minimum of 40 diameters of the reinforcement or 600 mm, whichever is greater. Welded or mechanical connections shall develop the full strength of the reinforcement.

e. Placing Grout

Use a hand bucket, concrete hopper or grout pump. Place grout in final position within 1-1/2 hours after mixing. Where grouting is discontinued for more than one hour, stop the grout 25-mm below the top of a course to form a key at pour points. Place grout to completely fill the gout spaces without segregation of the aggregates.

f. Tolerance

Lay masonry plumb, true to line, with course level. Keep bond patterns plumb throughout.

g. Cleaning

After mortar joints have attained their initial set but prior to hardening, completely remove mortar and grout daubs or splashing from exposed masonry surfaces. Before completion of the work, make out defects in joints in exposed masonry surfaces fill with mortar and tool to match existing joints. Immediately after grout work is completed remove scum and stairs which have percolated through the masonry using a high pressure steam of water and a stiff fiber bristled brush. Do not use metal tools or metal brushes for cleaning. Dry brush exposed concrete masonry unit surfaces at the end of work each day.


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The quantity to be paid for shall be the number of linear meter measured center to center of posts, of fencing erected in place and accepted.


The quantities, as determined in Sub-item 4.1 , Method of Measurement, shall be paid for at the contract unit price per unit of measurement, respectively for each of the particular Pay Items listed below and shown in the Bill of Quantities, which price and payment shall be full compensation for furnishing and placing all materials, including all labor, equipment, tools and incidentals necessary to complete the work prescribed in this Section. Payment will be made in accordance with the Bill of Quantities.

*****

Water Supply Wells

Bicol International Airport Development Project Section VI- Technical Specification Drilling Construction and Testing of Test/Production Well

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SECTION 1 – DRILLING, CONSTRUCTION AND TESTING OF TEST/PRODUCTION WELL 1.1 GENERAL

The Works include the construction of two (2) production wells. The well will be drilled and constructed in the area where the aquifer is made up of tuffaceous sand stone beds and sand and/or gravel layers within pyroclastic formations. The rocks of these two formations are semi to well consolidated and therefore relatively stable. Construction of production well shall consist of all work required in connection with drilling, development and testing of the borehole at the designated location as specified herein and on the Drawing showing the tentative well design or as directed by the Engineer including, but not limited to, mobilization, setting up, preparing the Site, making arrangements for the power and water required for drilling the pilot hole, formation sampling, collecting data and keeping records, making preparation for and executing geophysical logging, reaming the borehole, installing and removing temporary casing where necessary or other hole stabilization work if required, supplying and installing casing, cones, screen materials, centralizers, placing gravel pack, sand, grouting pumphousing, casing annulus, well development and test pumping as specified, dismantling, demobilizing and clearing up and restoring the Site.

Table 1.1 Well Details

Well Number Total Depth

(m) Borehole Diameter

(mm) Screen/Casing Diameter (mm)

PBH 01 80 350 200

PBH 02 80 350 200

1.1.1 TECHNICAL DEFINITIONS

a. The following definitions shall apply: (1) Borehole - means any drilled section of boring before completion as defined

in Well below.

(2) Casing - means non-slotted or non-perforated lining tubes. (3) Development equipment - means high velocity jetting tool, airlift equipment,

surge plunger and all other equipment needed to develop the well. (4) Diameters - means nominal diameters unless otherwise stated. (5) Drilling rig - means the drilling equipment and the auxiliary equipment for its

operation. (6) Drilling unit - as defined in Sub-section 1.2.2. (7) Final well design - means the drawing and description prepared by the

Engineer upon completion of drilling specifying the well components. (8) Lining materials - means any casing, screen, slotted lining or perforated lining

tube whether permanently or temporarily installed in the borehole. (9) Pumping unit - as defined in Sub-section 1.9.2.


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(10) Screens - means continuous wire wound stainless or low carbon steel screens, or slotted or perforated lining tube.

(11) Tentative well design - means the Contract Drawing showing the preliminary

design of the well. (12) Well - means any completed hole in which all lining material has been set, all

grouting completed and all temporary lining removed.

b. Technical Standards

All materials or workmanship shall comply with the Technical Specification. Other standards equal or superior to those enumerated, shall be acceptable, subject to the approval of the Engineer. The approval of the Engineer must be obtained prior to utilizing such materials or workmanship on or off the Site.

c. Water Supply and Illumination

In the absence of adequate quantities of water or illumination required for drilling at the Site, the Contractor shall make such arrangements including the provision for mobile tanks or fixed tanks as may be necessary to ensure a supply of water and illumination sufficient for drilling operations.

d. Electrical Power Supply

(1) The Contractor will make arrangements as may be necessary for the connection of or supply of power to the Site.

(2) Payment for the provision of electrical power supplies as specified in Sub-

clause d) (1) shall be deemed to be included in the prices entered in the Bill of Quantities for setting up equipment at the Site, drilling and for operation of the pumping unit.

e. Storage of Inflammables

The Contractor shall comply with all local authority regulations applicable to the use and storage of diesel oils, petrol, paraffin and other inflammable fuels used by him on the Site, and shall ensure that adequate precautions are taken against fire.

f. Boundaries of Site

The Owner shall provide land or rights-of-way for the Works specified in this Contract and make suitable provisions for ingress and egress, and the Contractor shall not enter or occupy with men, tools, equipment or material, any ground outside the property of the Owner without the written consent of the owner of such property. Other contractors and employees or agents of the Owner may, for all necessary purposes, enter upon the Site and premises used by the Contractor, and the Contractor shall conduct his work so as not to impede unnecessarily any work being done by others on or adjacent to the Site.

g. Access Roads

Construction or improvement of access roads to the wells shall, unless otherwise agreed, be done by the Contractor at his own cost, which is deemed to be included in the Contract Price. The access roads shall be kept in proper condition during the entire construction period.

h. Protection of Site


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(1) Excepting as otherwise provided herein, the Contractor shall protect all

fences, structures, footpaths, pipelines, trees, shrubbery, lawns, etc, during the progress of his work, shall remove from the Site all drill cuttings, debris, and unused materials, and shall upon the completion of the Works restore the Site to its original condition, including removal of access tracks and the replacement, at the Contractor's sole expense, of any facility or landscaping which has been damaged beyond restoration to its original condition to the satisfaction of the Engineer.

(2) Water pumped from the well shall be conducted to a place approved by the

Engineer where it will be possible to dispose the water without damage to property or creation of a nuisance.

i. Site to be Kept Tidy

The Contractor shall at all times keep the Site and all working areas in a tidy and sanitary condition and free from rubbish and waste materials.

j. Temporary Buildings for Use by Contractor

The Contractor shall provide at the Site such temporary buildings, tanks, workshops, etc. as may be necessary and proper for his general use in connection with the Works, and for the use of persons employed by him. The nature of the buildings, tanks, etc and the positioning of them shall be subject to the prior approval of the Engineer and the relevant authorities.

k. Shop Drawings

(1) The Contractor shall, if requested, prior to start of each operation, produce for the Engineer's approval shop drawings showing details of technical operations such as test of plumbness and alignment, the method of the slotted casing production, if so required, the methods of placement of formation stabilizer and/or cement grout, the arrangement for well testing, the method for well development and all other drawings pertinent to the well drilling, well construction operations and well development as requested by the Engineer.

(2). Shop drawings shall be completed with respect to dimensions, design,

design criteria, materials, methods of construction and the like to enable the Engineer to review the information, as required.

l. Well Head Protection

(1) At all times during construction, the Contractor shall protect the well in such manner as effectively to prevent either tampering with the well or the entrance of foreign matter until completion including the fitting of temporary well head cap satisfactory to the Engineer.

(2) In the event that the well becomes contaminated or that water having

undesirable physical or chemical characteristics has entered the well the Contractor shall at his own expense perform such work or supply casings, seals, sterilizing agents or other materials as necessary to eliminate the contamination and to exclude any undesirable water from the well.

m. Transport of Personnel and Equipment

(1) The Contractor shall supply and operate all transport required for transporting


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his employees, materials and equipment.

(2) The cost of movement of personnel, materials and equipment shall be included in the prices inserted in the Bid Form for drilling, development and pump operation.

n. Site Preparation and Restoration

(1) The Contractor shall prepare the Site, provide all necessary tanks and pits and make all necessary arrangements for erecting and dismantling the drilling unit and all other equipment used for well construction, development and testing and shall on completion of each phase of work restore the Site to the satisfaction of the Engineer.

(2) The costs shall be deemed to be included in the prices entered in the Bid

Form for the relevant items. o. Standing Time

Standing time will be paid only when drilling is suspended on the written instruction of the Engineer.

Payment shall be made for the number of days of standing per drilling rig at the unit price given in the Bid Form for stand-by charge.

1.2 WELL DRILLING 1.2.1 SCOPE

a. The Contractor shall provide and operate a mobile drilling unit required to complete

the Works within the construction period. b. The Contractor shall provide all auxiliary equipment, lubricants, fuels and spares

necessary to keep the drilling rig(s) in continuous operation.

1.2.2 EQUIPMENT a. The drilling rig(s) together with all auxiliary equipment and personnel shall be defined

as the drilling unit(s). b. All rigs shall have sufficient capacity to drill the specified borehole at the diameters

specified and to a depth which is a minimum 25% deeper than that indicated on the Drawing showing the tentative well design.

c. Payment for drilling will be by the linear meter of borehole as measured after removal

of drill string. The unit prices set against drilling items in the Bid Form shall be deemed to include all equipment, personnel, fuels and lubricants and the accessories required for operation of the drilling unit.

d. When the drilling unit is being used for a purpose other than drilling, then the unit

prices for that purpose entered in the Bid Form shall be deemed to include the running costs of the drilling unit.

e. The Contractor shall provide and operate a minimum of three (3) rotary drilling rigs

including all auxiliary equipment necessary to complete the Works as designed within the construction period stipulated.


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1.2.3 DRILLING METHOD a. The production well shall be drilled by the rotary method using sound drilling practice

approved by the Engineer. b. The Contractor shall drill the hole to such depth and with such a diameter which shall

enable easy installation of casing and screen and placement of gravel envelope with a uniform thickness as specified. During drilling of the hole, the Contractor shall ensure that the natural permeability of the yielding strata near the well bore is not irreversibly reduced due to the drilling method employed.

c. The provision of an uninterrupted supply of drilling water is the sole responsibility of

the Contractor. The capacity of the settling pond shall be approximately three times the volume of the borehole. Except where ordered in writing by the Engineer no over drilling will be measured for payment. Any over drilling required by the Contractor to facilitate installation of casing/ screen shall be done subject to the prior approval of the Engineer at the Contractor’s expense.

1.2.4 HOLE DEVIATION AND STRAIGHTNESS

The borehole shall be drilled straight and concentric within the plumb limits specified. To

achieve this, the Contractor shall use a deviation survey instrument which shall be run within the drill string on completion of the drilling of the upper pump housing and again prior to extraction of line drill string on termination of the borehole.

1.2.5 WATER LEVEL SOUNDING INSTRUMENT The Contractor shall provide an accurate water sounding instrument acceptable to the

Engineer to measure the water level during all drilling, development and testing of the well. This instrument will be retained by the Owner after final acceptance of the Works. Failure to provide such an instrument will subject the Contractor to a penalty of P100.00 per day.

1.2.6 STRATA SAMPLING a. Strata samples shall be taken at 1 meter intervals or more frequent if the formation

penetrated changes. Samples shall be placed in plastic or other appropriate bags on which or in which the sampling depth and the date of sampling is written in such a manner that it is permanently readable.

b. The sampling procedure must provide that all the fractions of the penetrated strata

are present in the sample. c. Each sample shall be placed in a wooden box with space for storage of one sample

and the sampling depth shall be written on the box. d. A record of samples taken with the details described above, shall be submitted to the

Engineer every day. e. Payment for sampling shall be deemed to be included in the unit prices entered for

drilling in the Bill of Quantities. f. Failure on the part of the Contractor to obtain, preserve and deliver samples or

records, satisfactory to the Engineer, shall be considered as actual damage to the Owner. Such a failure shall authorize the Engineer to retain from money due or to become due the Contractor the sum of One Thousand Pesos (P1000.00) as liquidated damages for each sample that the Contractor shall fail to obtain, preserve


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or deliver, or for each length of pipe not properly measured and recorded in the order in which it was placed in the well. In the event that, in the opinion of the Engineer, the failure of the Contractor to take and preserve the samples may affect the proper design of the well, the Contractor may be required to perform such work as the Engineer deems necessary to remedy such failure at no cost to the Owner. It is understood that the liquidated damages herein provided are fixed, agreed and not by way of penalty; and that the Owner shall not be required to prove that he has incurred actual damages.

1.2.7 DRILLING MUD

a. Bentonite, if used, shall be of premium quality in accordance with API Standard 13A

with 150 kg/m3 of make-up water yielding a mud with a viscosity of between 35 and 40 seconds using a Marsh Funnel and a mud weight of less than 1.10 kg/l (9.2 lb./US gal.).

b. Make-up water shall be treated with caustic soda (soda ash) to maintain the pH

between 8.0 and 9.0 prior to mixing mud. c. During drilling with mud, the Contractor shall perform hourly measurements of the

following mud characteristics:

- pH value - Funnel viscosity - Specific gravity - Sand content - Filtration loss - Filter cake thickness

d. The recorded mud characteristics shall not exceed the following values, without the

prior approval of the Engineer:

- Specific gravity : 1.10 kg/l - Sand content : 4 % - Filtration loss : 10 ml - Filter cake : 1.5 mm

1.2.8 WORKING HOURS

All work from start of drilling of the borehole until completion of well development shall, if the rotary drilling method is applied, be on a round the clock basis.

1.3 GEOPHYSICAL LOGGING 1.3.1 SCOPE OF WORK

Geophysical logging comprising electric resistivity and self-potential logs of the unlined portions of the pilot hole is to be undertaken by the Contractor using equipment linked to a computer and printer giving a continuous print out of the results. The print out shall be presented to the Engineer immediately. The Contractor shall submit the interpretation of the log together with data recorded on a CD within 5 days of the completion of logging.

1.3.2 EQUIPMENT

a. The geophysical logs may be recorded either by automatic recording on a chart strip or by manual reading of recorded values. In case the logs are recorded by the manual method, readings shall be taken at minimum intervals of 0.33 m of borehole length.


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b. The recorded logs shall be submitted to the Engineer immediately upon completion of

logging as plots of recorded characteristics versus depth for his approval. In case of disapproval by the Engineer, the logs shall be repeated immediately.

1.3.3 LOGS

Geophysical logging shall comprise the following logs: - caliper log - resistivity log (400 mm & 1600 mm) - gamma ray log - self-potential log (SP).

1.4 WELL CASING 1.4.1 SCOPE

The Contractor shall provide and install the well casing and shown on the Drawings and any temporary casing required during construction. a. Casing Material

(1) The Contractor shall, before commencement of work, submit for the approval

of the Engineer the following details of all casing:

i. Type of material;

ii. Internal and external diameters;

iii. Wall thickness;

iv. Method of jointing.

(2) All permanent casing material shall be of new stock unless otherwise specified.

(3) The Contractor shall assume responsibility for any casing failure and shall

correct, as approved by the Engineer, any casing failure at no cost to the Owner. In the event that the Contractor cannot correct a casing failure, the Contractor shall replace the casing with material complying with the Specification, or if necessary, as approved by the Engineer at no extra cost to the Owner.

b. Permanent Casing

(1) All permanent casing shall be spiral welded, low-carbon steel pipe with a

minimum wall thickness of 6 mm. Casing shall be of new stock and shall be water-tight. The outside diameter of the casing shall be as indicated on the Drawing for the tentative well design. Pipe ends shall be bevelled to facilitate welding and shall precisely match the diameter of abutting well components including the stainless steel screens.

(2) Reducing cone(s) and tapered sump pipes(s) shall be factory or workshop

manufactured from low-carbon steel to the dimensions indicated on the Drawings or as approved by the Engineer and shall precisely match abutting pipe or screen.


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c. Temporary Casing

The Contractor shall furnish and install all temporary casing as required for construction convenience or expediency. Casing should only be installed with the approval of the Engineer. The Contractor shall provide such temporary casing as may be necessary to prevent the collapse of any formation during the drilling operation to allow the well to be sunk to the specified depth and to allow the installation of permanent lining material as required. Casing shall be of such weight and design as necessary to prevent entrance of sand and silt, to be reasonably water-tight and to permit its installation without distortion or rupture to the depth and dimensions. All casing shall be removed before completion of the well and shall remain the property of the Contractor.

d. Lining Installation

(1) Lining material shall be assembled and located in the well at the required

depth in a continuous operation. The lining material shall be set concentric within the borehole by centralizing bars unless otherwise agreed with the Engineer.

(2) If the lining jams or is lost before it is set to the specified depth, the

Contractor shall endeavor to remove the lining material from the well or, if unable to effect removal, shall abandon the well and drill a replacement well. No payment shall be due for the abandoned well nor for any lining installed therein.

e. Lining Material Accessories

(1) The Contractor shall provide as necessary the following accessories to set

the lining material to the required depth:

i. Centralizers to be affixed to the lining material at intervals of 12 m to locate the lining material in the center of the borehole;

ii. Supporting clamps, equipment and tools; iii. Reducing cones and connecting pieces; iv. Casing hangers; v. All other necessary equipment.

(2) The cost of all accessories shall be deemed to be included in the Bill of

Quantities for the provision and installation of lining material.

f. Testing for Plumbness and Alignment

(1) All boreholes shall be constructed plumb and true to line as defined herein. To demonstrate compliance with this requirement, the Contractor shall furnish all labor, tools and equipment and shall provide drawings and a description of the tests to the satisfaction of the Engineer.

(2) Tests for plumbness and alignment must be made after the complete

construction of the well and before its acceptance. Additional tests, however, may be made by the Contractor during well construction. No specific payments shall be made for making these tests.


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(3) Should the results of the tests for plumbness and alignment show that the

plumb bob or dummy fails to move freely throughout the length of the lining or borehole to a depth of the lowest anticipated pump setting and should the well vary from the vertical in excess of two-thirds of the smallest inside diameter of that part of the well being tested or beyond the limitations of this test, the plumbness and alignment of the well shall be corrected by the Contractor at his own expense. Should the Contractor fail to correct such faulty alignment or plumbness, the Engineer may refuse to accept the well. No payment shall be made for the abandoned well. The Contractor shall drill a new well to the approval of the Engineer.

1.5 WELL SCREENS 1.5.1 SCOPE

The Contractor shall provide and install the well screens specified and shown on the Drawings.

1.5.2 TYPE OF SCREEN

The screens shall be stainless steel AISI Grade 304 SS or equivalent continuous slot wedge wire-wound with slot size 1.5 mm (slot 60), 3 meter length per piece. Each piece of screen shall be marked with an indelible marker with a unique identification mark. Slotted screens shall be so fabricated as to ensure the maximum yield of the well and to prevent clogging and encrustation and shall be free from jagged edges and irregularities that may accelerate clogging or corrosion. Stainless steel screens shall be of new stock and shall comply with the following criteria:

SCREEN DETAILS

Nominal Diameter (mm) 200 Outside diameter (mm) 219 Length - including weld ring (m) 3 Minimum open area (%) 30 Slot opening tolerance (mm) +/- 0.1 Collapse Pressure (K Pascal) (minimum) 1484 (psi) 210 Tensile strength (Kg) (minimum) 32,000 Transmitting capacity (lps/m of screen) Using 0.03m/sec entrance velocity

6.0

Details of the screen to be supplied by the Contractor shall be submitted together with the bid. The Contractor shall submit to the Engineer for approval the shop drawing for the stainless steel screen. A certificate stating the detailed specification of the screen materials shall accompany the screens on delivery to the Site.

1.5.3 SCREEN STRENGTH

The screens shall have adequate strength to resist the external forces that may be applied during and after installation.


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1.5.4 RESPONSIBILITY FOR MALFUNCTION

a. The Contractor shall assume full responsibility for any malfunction of the screen caused by inadequate installation procedure and shall undertake any correction as approved by the Engineer at no extra cost to the Owner.

b. The screen must have no change of alignment at any of its joints after installation. If

requested, the Contractor shall submit for approval by the Engineer the design and method of fabrication of the screen.

c. In the event that the Contractor cannot correct a screen failure, the Contractor shall

replace the screen with material complying with the Technical Specification at no extra cost to the Owner.

1.5.5 SCREEN ACCESSORIES

All fittings, packers, couplings, joints, plugs and seals used during installation of well screen together with the installation procedure, shall be to the approval of the Engineer.

1.5.6 SIEVE ANALYSES

The Contractor shall conduct sieve analyses of samples taken from all potential aquifers in order to determine the most suitable slot opening and gravel pack grading. A maximum 1 kg sample representing each potential aquifer horizon shall be collected, washed to remove drilling mud and dried. The dried sample shall be quartered until 400 grams are left for sieving. For a thick, multi-layered aquifer horizon, samples taken from the fine-textured layer shall be taken and sieved to represent the whole aquifer horizon. The recommended mesh number and range of sizes of the sieves to be used are as follows:

Mesh Number Size in mm Mesh Number Size in mm

150 0.105 18 1.000 60 0.246 16 1.190 40 0.420 12 1.680 30 0.590 10 2.000 20 0.840 7 2.830

The Engineer will determine the gravel pack grading based on the sieve analyses.

1.6 WELDING

Welding shall be carried out using materials strictly compatible with the stainless steel screen and low carbon steel casing materials.

1.7 FORMATION STABILIZER/GRAVEL PACK

1.7.1 SCOPE

The Contractor shall provide and install formation stabilizer, or gravel pack if shown on the Drawings.

1.7.2 MATERIAL

a. The formation stabilizer/gravel pack material shall consist of well rounded, water-


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worn siliceous grains. (Under no circumstances may angular chippings or road stone be used as formation stabilizer/gravel pack material.)

b. The Contractor shall, during the mobilization period, submit to the Engineer for his

approval, samples of the formation stabilizer he proposes to use, stating the source, quantities available, rate of delivery and any other information requested.

c. Graded gravel pack materials shall have grain size 4 - 7 mm with a uniformity

coefficient (Cu) less than 2 where,

Cu = D60

D10

1.7.3 METHOD OF INSTALLATION

a. The method of placing the formation stabilizer/gravel pack in the annulus shall be such that separation of the gravel and bridging is avoided.

b. The formation stabilizer/gravel pack shall immediately upon completion of lining

installation, be placed in the annulus between the borehole and the lining, in the screened section(s) of the lining, as indicated on the Drawing showing the final well design.

c. If the borehole was drilled by the rotary method, installation of formation

stabilizer/gravel pack shall be done by circulation of the drilling mud. 1.8 WELL DEVELOPMENT 1.8.1 SCOPE

a. The Contractor shall furnish compressors, surge plungers, jetting tools, electric generators, chemicals and any other equipment required for satisfactory well development and shall undertake the development as directed by the Engineer.

b. Development shall, if the rotary method is applied, comprise deflocculation, high

velocity jetting for continuous slot screens, surging with plunger for slotted screens and development which shall consist of surging and bailing of sediments, overpumping and airlifting.

c. Expected Yield

The expected yield of each production well is given below:

Well Number Depth (m) Expected Yield PBH-01 80 7.50 PBH-02 80 7.50 When the water discharged from the well is confirmed sand free the Engineer shall issue a certificate stating the well discharge and sand content and confirming that well development is complete.

1.8.2 SURGING WITH PLUNGER

a. Upon completion of installation of lining or formation stabilizer/gravel pack, the Contractor shall develop the well by mechanical surging with a valve-type surge plunger approved by the Engineer.


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b. Before start of surging and with 1 hour intervals during the surging operation, the depth to the well bottom and to top of gravel pack shall be recorded.

c. Surging shall be continued until accumulation of sediments in the sump pipe, during a

1 hour period surging operation is negligible.

1.8.3 DEFLOCCULATION (APPLICABLE FOR ROTARY METHOD ONLY) a. Upon completion of installation of lining or formation stabilizer/gravel pack, the drilling

mud shall immediately be displaced from the well by pumping clean water into the sump pipe.

b. Mud displacement shall immediately be followed by injection and/or jetting through

the screened sections with a polyphosphate solution to deflocculate the mud cake on the borehole wall. The concentration of the polyphosphate solution shall be 3 percent by weight of the quantity of the water in the borehole. The well shall then be left for 12-24 hours to allow the polyphosphate to react, before developing is continued.

1.8.4 HIGH VELOCITY JETTING

a. After the deflocculation material has been allowed to react for 12-24 hours all sections screened with continuous slot screens shall be developed by high velocity jetting.

b. The jetting tool shall be equipped with two or four nozzles. The nozzle design shall be

such that it produces a concentrated jetting action. The tool shall be presented to the Engineer for approval before the start of the drilling operation.

c. The jetting tool shall be supplied with water through a high-pressure pump capable of

producing a nozzle velocity of 50-70 m per second. The pump shall be equipped with a suitable pressure gauge on the discharge side to facilitate monitoring of nozzle velocity.

d. The development shall be carried out by slowly rotating the jetting tool and gradually

lowering it in order to cover the entire surface of the screen. e. At the same time as the high velocity jetting is performed, the well shall be

discharged with a discharge rate slightly higher than the discharge rate from the jetting tool.

f. Each section of the screen shall be jetted until the return water is free from drilling

mud, but no section shall be jetted less than 20 minutes per meter of screen.

1.8.5 DEVELOPMENT BY AIRLIFTING

a. Upon completion of high-velocity jetting, and/or surging with plunger, the well shall be discharged by the airlifting method.

b. The compressor used for pumping by airlifting shall be capable of developing a

pressure not less than 100 psi. The delivery shall be no less than 7 m3 air per minute.

c. The quantity of water discharged from the well and the drawdown in the well at the

commencement of the development shall be limited and shall be gradually increased only as the water clears. From time to time the air flow shall be stopped to facilitate loosening of trapped sand grains. The well may also be backwashed by pumping clean water into the well.


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d. During the airlifting operation the position of the air pipe and conductor pipe, drawdown in well, approximate yield and time for each change in position shall be recorded by the Contractor.

e. The development shall be completed with a conductor pipe not more than 0.5 m

above the bottom of the well to ensure that all sand has been removed from the sump pipe.

1.8.6 WELL CLEANING

Upon completion of the development operations, the Contractor shall demonstrate to the satisfaction of the Engineer that the bottom of the well is clear of all sand, mud and other foreign materials.

1.8.7 FREEDOM FROM SAND

a. The Contractor shall develop the well by the methods specified until the water pumped from the well is substantially free from sand and until the turbidity is less than 5 on the Silica Scale described in Standard Methods of Water Analysis (latest edition as published by AWWA, APHA and WPCT).

b. The water pumped from the well shall not contain an amount of fine material in

excess of 1.0 mg per liter when the well is pumped at its maximum expected yield. The equipment for measurement of the sand content shall be furnished by the Contractor.

1.8.8 ACCEPTANCE OF DEVELOPMENT

a. The development by the specified methods shall be repeated and continued until the well is thoroughly developed in accordance with the criteria specified in Sub-section 1.8.7.

b. If the yield after the well has been confirmed sand-free is below the yield considered

acceptable for the penetrated aquifer, then the Engineer may instruct the Contractor to perform further development.

1.9 WELL TESTING 1.9.1 SCOPE

The Contractor shall provide and operate a pumping unit for the following purposes:

a. Step-drawdown pumping tests on the constructed well; b. Constant discharge pumping and recovery tests on the constructed well. c. Should it be proven by the Engineer that completing the 48-hour continuous constant

discharge pumping test is unnecessary and/or not possible, the Contractor shall be paid an amount corresponding to 24 hours of pumping.

1.9.2 EQUIPMENT CAPACITY

a. The Contractor shall provide and operate pumping machinery capable of carrying out the specified pumping and shall provide adequate controls to allow discharge rates to be kept constant at varying pumping water levels and to permit pumping with a variation of not more than 5% of the designated discharge rate during any period of yield or aquifer testing.


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b. The pumping unit set shall be able to deliver a discharge rate, which is a minimum of 50% higher than the expected yield of the well and a minimum discharge, which is a maximum of 15% of the expected yield of the well when suitably throttled by use of a gate valve.

c. Suitable pumping machinery will be deemed to be:

(1) Submersible electric pump unit together with generator and such accessories needed to run the pump.

(2) Line-shaft pump and internal combustion prime mover together with all accessories needed to run the pump.

1.9.3 EQUIPMENT OPERATION

a. The Contractor shall supply and operate all equipment and accessories necessary for

installation and removal of pumps.

b. The Contractor shall maintain on Site sufficient fuels, lubricants, spares and other accessories needed to run the pumping unit for whatever period may be specified by the Engineer.

c. The Contractor shall provide sufficient competent personnel including a qualified fitter

and electrician, as may be necessary to install and operate the pumping unit.

1.9.4 CONTROL OF DISCHARGE RATE The Contractor shall, during the pumping tests, provide a suitable gate valve on the discharge pipeline, to facilitate control of the discharge rate.

1.9.5 WATER LEVEL SOUNDING PIPE

a. The Contractor shall, if instructed by the Engineer, provide and install a temporary tube of at least 25 mm diameter from the top of the well to 2 m above the pump bowl assembly to facilitate easy measurement of water level. The tube shall be open only at the bottom and top.

b. Payment for providing, installing and removing the tube shall be deemed to be

included in the prices inserted in the Bid Form for pumping tests.

1.9.6 DISCHARGE RATE MONITORING

Discharge rates up to 15 lps (54 m3/hr) may be measured by drum filling. Discharge rates in excess of 15 lps shall be recorded with a water meter or by a V-notch weir. All items are subject to the Engineer's approval before the start of drilling.

1.9.7 DEFINITION OF "PUMPING UNIT"

The equipment specified in Sub-section clause 39.08 (ii) and (vi) is referred to as the pumping unit.

1.9.8 PUMPING PROCEDURE

The Engineer will determine the pumping procedure required.

1.9.9 SUSPENSION OF PUMPING

If the condition of any equipment, personnel, fuel, lubricants or accessories may prejudice the


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quality of data obtained from any pumping test the Engineer may suspend the work in accordance with the provisions of the General Conditions.

1.9.10 EQUIPMENT BREAKDOWN DURING PUMPING

a. Pumping must be continuous and at a constant rate during the tests. The Engineer will instruct the Contractor as to the expected maximum duration of each pumping test before the start of each test.

b. If pumping is interrupted or the discharge rate fluctuates by more than 5% of the

designated discharge rate, the test shall be repeated after a period of recovery as determined by the Engineer.

c. If any pumping test is interrupted because of equipment breakdown or inadequate

supervision or discharge control, no payment will be made for any pumping period before recommencing the test.

1.9.11 DURATION OF TESTS

a. The step-drawdown pumping tests shall be performed in 5 steps with a duration of 2 hours each.

b. The constant discharge pumping tests shall be performed for a period of 2-3 days or

unless otherwise instructed by the Engineer. c. The recovery test shall be performed for not more than 24 hours or until the original

static water level position is reached, whichever occurs first.

1.9.12 TEMPORARY PIPELINE

a. The Contractor shall provide a temporary pipeline as directed by the Engineer for the discharge of water from the well during the pumping tests and for disposal to a suitable water course or drain.

b. Under certain circumstances when re-infiltration cannot be avoided or it would be

excessively costly to provide for this condition, the Engineer shall decide to what distance from the well, well water may be discharged onto the ground.

1.10 CEMENT GROUTING 1.10.1 SCOPE

To prevent possible contamination of surface water, the upper 15 m of the annulus between the casing and borehole shall be grouted with cement as shown on the Drawing for the tentative well design.

1.10.2 GROUTING MATERIAL

a. Cement grout shall consist of a mixture of 95% Portland cement, 5% bentonite and clean water, mixed in the proportion of 52.5 kg of Portland cement/bentonite to a maximum of 30 liters of water.

b. All cement shall, unless otherwise specified in the Contract Documents, conform to

the "Specifications for Portland Cement" (ASTM C150-latest revision).


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1.10.3 METHOD OF PLACING GROUT MATERIAL

a. The method and equipment for placing the grout shall be to the approval of the Engineer. No method will be approved that does not provide for the forcing of grout from the bottom of the casing/hole/annulus to be grouted, to the surface. Flushing of the annular space with fluid to assure the space is open and to remove loose material will be required before grouting is commenced.

b. Any grouting operation shall be continuous and before starting, sufficient grout shall

be mixed to complete the whole operation. During the grouting operation, the mixed grout shall be continuously stirred.

1.10.4 SETTING TIME

No work will be allowed on the well within a period of 72 hours after completion of grouting unless a quick setting cement is used. In such case, the idle period may be reduced to 24 hours subject to the Engineer's prior approval.

1.11 CHLORINATING EQUIPMENT

1.11.1 HYPOCHLORINATING EQUIPMENT

a. General – The hypochlorite feed pump shall be of the positive displacement type with all parts constructed of materials non-corrosive to wet chlorine service.

b. Capacity – The feed pump shall have a maximum operating capacity of 5 ppd of

hypochlorite solution and shall be equipped with manually operated knob control mounted on top of the pump suitable for the above maximum feed rate. A feed indicator shall permit visual monitor of fluid rate at any time.

c. Operation – The rate of hypochlorite solution feed shall be set manually and shall

remain constant until manually changed. Feed rate adjustment shall be permitted while the unit is in operation. The hypochlorite feed pump shall be rated 230 VAC, single phase and 60Hz.

d. Standard Accessories – The hypochlorinator shall be supplied with lubricating oil,

suction and discharge tubings with appropriate fittings, anti-siphon valve, foot valve, strainer, check valve with pipe fittings for injection into the water main, three (3) plastic solution tanks with cover to hold 50 gallons of hypochlorite solution and plastic measuring cup.

e. Powder Chlorine – The unit shall be provided with one (1) drum (45 kgs) of calcium

hypochlorite powder with 70% available chlorine. f. Chlorine Test Kit – The test kit shall be of colorimetric type and the residual chlorine

shall be determine by a simple visual comparison between permanent color standards of known value and sample color. The test kit shall be capable of analysing for total chlorine using orthotolidine solution method. The unit shall have a range of 0-5m/l or ppm with increments of 0.1 mg/l or ppm. Orthotolidine solution shall be provided with the test kit.

1.12 WELL DISINFECTION AND CLEANING 1.12.1 SCOPE

a. The Contractor shall upon completion of well construction and testing thoroughly


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clean the well of all foreign substances including tools, timbers, rope, debris of any kind, cement, oil, grease and scum.

b. The casing pipe shall be thoroughly swabbed using alkalis, if necessary, to remove

oil, grease and joint dope. The Contractor shall then disinfect the well with a chlorine solution.

1.12.2 PROCEDURE

The required quantities of calcium hypochlorite powder or other approved disinfectant shall be mixed with water in a suitable container of sufficient capacity to ensure complete sterilization of the well water with the application of a solution giving a concentration of 100 mg/l of free chlorine in all parts of the well. The solution shall be introduced to the well taking care to apply disinfectant solution to all areas of casing above the static water level. The Contractor shall provide reliable means for ensuring that the disinfectant agent is uniformly applied throughout the entire water depth of the well. Any mechanical or surging action adopted for agitation of the disinfectant shall be carried out under careful control to avoid risk of screen damage to the approval of the Engineer. All accessible portions of the well above the static water level shall be maintained in a damp condition with water containing the required concentration of disinfecting agent for a period of not less than 20 minutes. The disinfecting agent shall remain in the well for a period of 8 hours. Measurement of the chlorine residual in a water sample taken from the well shall be done at the end of the shown contact period using a suitable chlorine comparator test kit procured by the Contractor to the approval of the Engineer. The test kit shall be retained by the Owner. The procedure shall be accepted as complete provided there is a detectable chlorine residual in the water sample. If ordered water shall be pumped from the well until the chlorine residual is less than 10 ppm. The disposal point for the purged water shall be selected so as to minimize potential damage to the population, aquatic life and vegetation. The following table gives the amount of calcium hypochlorite (70%) available chlorine required to provide a dosage of 100 mg/l of available chlorine.

Table 1.2 - Chlorine Compound Required to Dose 1 m Depth of Water-Filled Well

Diameter of

Casing (mm)

Volume per m of Depth (liters)

Amount of Calcium Hypochlorite in gms per m of Depth at 100 mg/l of Free

Chlorine 200 32 4.5

1.12.3 REQUIREMENTS FOR DISINFECTION OF TEST PUMPS

In the event that the test pump is to be installed after the well has been disinfected, all exterior parts of the test pump coming in contact with the well water shall be swabbed with a chlorine solution as directed by the Engineer.

1.13 WELL SOUNDING

On completion of well testing and prior to acceptance, the well shall be sounded to confirm the cased depth. The well may be accepted by the Engineer provided the depth of silt accumulated in the sump pipe does not exceed 0.3m. Silt in excess of 0.3m shall be


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removed by the Contractor. 1.14 WELL COMPLETION 1.14.1 SCOPE

The Contractor shall provide and operate all equipment necessary for restoration of the Site and shall furnish and install a well head cap as shown on the Contract Drawings.

1.14.2 SITE RESTORATION

The Site shall be restored to the condition which existed before the well drilling and testing activities commenced. This work shall include, but not be limited to, restoration of fences and structures, removal of drill cuttings, leveling of the disturbed ground surfaces and replacement or compensation for the destroyed plants and landscaping. Payment for restoration shall be deemed to be included in the unit price entered in the Bid Form for demobilization.

1.14.3 WELL HEAD CAPPING

The well head shall be completed with a lockable well head assembly on the upper casing as well as a water level sounding tube with screw cap to prevent any unauthorized tampering with the well.

1.15 SUBMITTAL OF REPORTS AND BOREHOLE DATA 1.15.1 SCOPE

a. The Contractor shall submit to the Engineer daily records in duplicate containing the following information:

- Site; - Date; - Description of each stratum encountered; - Depth below ground of each change of stratum; - Depths and details of all disturbed samples.

b. The Contractor will be required to keep records of penetration rates, mud losses and

mud conditions. c. At the end of the well construction and before final payment is made, the Contractor

shall submit to the Engineer a report containing the following information for each well:

(1) The date of the start and the completion of well construction; (2) The total depth of the well; (3) A copy of the geophysical log together with interpretation; (4) Description of the strata encountered; (5) The sizes and the lengths/specification of the casing installed; (6) The locations and the detailed specification of the casing perforations or the

well screens;


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(7) The locations of the gravel pack, the gravel pack grading, and the amount of

cement grout installed; (8) Records of discharge rates and drawdown during well development together

with description of the methods of the development; (9) The yield (expressed as discharge rate and drawdown), the dates and the

duration of the test(s); (10) The methods of measuring the discharge rate and the drawdown; (11) Plumbness test results; (12) Water sample analyses results; (13) Any further technical information pertinent to the wells and their construction

as required by the Engineer. The data shall be compiled and bound in a hardback folder to the approval of the

Engineer.

d. The cost of maintaining records and producing reports shall be deemed to be included in the prices included in Bid Form.

*****

Bicol International Airport Development Project Section VI- Technical Specifications Submersible Deepwell Pumps

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SECTION 2 - SUBMERSIBLE DEEPWELL PUMP

PART 1 – GENERAL

1.1 SCOPE

This section covers the submersible deepwell pump installed as indicated on the drawing.

The pumping unit shall be complete with a close coupled, submersible electric motor, inlet strainer, non return valve, priming screw and all other appurtenances specified or otherwise required for proper operation.

Equipment furnished and installed under this section shall be fabricated, assembled, erected, and placed in proper operating condition in full conformity with drawings, specifications, engineering data, instructions, and recommendations of the equipment manufacturer unless exceptions are noted by the Owner.

1.2 REFERENCES

Governing Standards. Except as modified or supplemented herein, all equipment and materials required in this section including their installation shall conform to the applicable requirements of the following standards. Standards current at the time of tender shall be used.

1.2.1 American Society for Testing And Materials (ASTM)

A 307 Carbon Steel Bolts and Studs, 60000 PSI Tensile Strength 1.2.2 ASME International (ASME)

B1.1 Unified Inch Screw Threads (UN and UNR Thread Form) B16.1 Cast Iron Pipe Flanges and Flanged Fittings B16.5 Pipe Flanges and Flanged Fittings NPS 1/2 thru NPS 24 B40.1 Gauges - Pressure Indicating Dial Type - Elastic Element

1.2.3 American Water Works Association (AWWA)

E101 Vertical Turbine Pumps - Line Shaft and Submersible Types 1.2.4 American Bearing Manufacturers Association (ABMA)

Std 9 Load Ratings and Fatigue Life for Ball Bearings 1.2.5 National Electrical Manufacturers Association (NEMA)

MG 1 Motors and Generators 1.3 COORDINATION

All equipment included in this section shall be furnished by or through a single

manufacturer who shall be responsible for the design, coordination, and the satisfactory


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performance of all the components over the full operation range.

1.4 QUALITY ASSURANCE

1.4.1 BALANCE

All rotating parts shall be accurately machined and shall be in as nearly perfect rotational balance as practicable. Excessive vibration shall be sufficient cause for rejection of the equipment. The mass of the unit and its distribution shall be such that resonance at normal operating speeds is avoided.

1.5 SUBMITTALS

Complete specifications, data, and catalog cuts or drawings covering the submersible pump

and accessories shall be submitted.

1.5.1 Drawings and Data

Complete fabrication, assembly, foundation, and installation drawings, together with detailed specifications and data covering materials used, parts, devices, and accessories forming a part of the equipment furnished. The data and specifications for each unit shall include, but shall not be limited to, the following:

a) Pumps

(1) Name of manufacturer.

(2) Type and model.

(3) Rotative speed.

(4) Number of stages.

(5) Type of bearings.

(6) Net weight of pump and motor only.

(7) Complete performance curves showing capacity versus head, h

(8) NPSH required, efficiency, and kW input.

(9) Data on shop painting.

b) Motors


(2) Type and model.

(3) Type of bearings and lubrication.

(4) Rate size of motor, kW.

(5) Temperature rating.

(6) Full load rotative speed.

(7) Net weight.

(8) Efficiency at full load and rated pump condition. (9) Full load current. (10) Locked rotor current.

c) Control Panel and Components.


(2) Type and model.

(3) Dimensions and net weight of complete panel.

(4) Overcurrent characteristics and details of motor control.


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1.5.2 OPERATIONS AND MAINTENANCE MANUALS/CHARTS AND SPARE PARTS DATA

Upon submission of shop drawings and prior to the shipment of the equipment, submit three (3) preliminary copies of operations and maintenance manuals for preliminary review by the Owner.

Final copies of operations and maintenance manuals/charts and spare parts data shall be submitted in accordance with the requirements set forth at the Conditions of Contract.

1.6 PROJECT CONDITIONS

1.6.1 POWER SUPPLY

Power supply to equipment shall be as indicated on the drawing. 1.6.2 INSTRUCTIONS AND TRAINING ON OPERATION AND MAINTENANCE

Contractor shall provide instructions and training for the staff to be assigned in the operation and maintenance of the equipment specified under this section. Training and instructions shall be in accordance with the requirements set forth at the Conditions of Contract.

PART 2 - PRODUCTS

2.1 SUBMERSIBLE DEEPWELL PUMP

The Contractor shall furnish and install, as shown on the drawings as described in these specifications, a submersible multi-stage vertical turbine pump capable of delivering 120 gallons per minute (gpm) against a total dynamic head (TDH) of 300 feet. The pump shall be coupled to a 3 phase, 3500 rpm, 60 cycle, 230 volts, submersible motor. The motor shall not be less than 15 hp and of such size that will operate continuously without exceeding its hp rating, exclusive of service factor, at a design capacity and head. Motor shall of the squirrel cage induction type, suitable for “reduce voltage type” starting. The motor shall be capable of continuous operation under water at the conditions specified. The power output shaft shall be of stainless steel equivalent corrosion resistant material.

Pump Motor Coupling shall be of 416 stainless steel and shall be capable of transmitting the total torque to the unit, regardless of the direction rotation. Pump Bowl Assembly shall include bowls made of close grained cast iron, free from blow holes, sand holes or other detrimental defects, with a tensile strength of 30,000 psi. Each intermediate bowl shall be constructed with bronze bearing and a neoprene bearing to support the impeller shaft. These “dual bearings” shall provide the longest possible shaft life, based on the widest range of pumping pressure at the rated capacity or 1.5 times the shutoff head, whichever is greater. Impellers shall be the enclosed type with sufficient skirt material, thickness to enable repair and restoration of proper running clearances by installation of wearings. The impeller shaft shall be made of 416 stainless steel. Each impeller shall be made of bronze, accurately machined and finished, and suitably balanced. Each impeller shall be securely fastened to the shaft with a taper lock busing. The bowl shall include a side seal at the impeller skirt and, in addition, a resilient neoprene ring, reinforced with an embedded steel core, installed directly below the impeller skirt. This durable, resilient “lateral bowl wearing” shall protect the end of the impeller skirt against wear from entrained abrasives. The close running clearance between the impeller skirt and the “lateral bowl wearing” shall provide sustained protection against bowl re-circulation and consequent reductions in efficiency. The bowl unit shall include a bearing to carry the momentary upthrust encountered at start-up.


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The bowl unit shall include metal guard to protect the motor cable from abrasion during installation. Inter-connector made of close grade cast iron, shall couple the bowl unit to the motor. The inter-connector shall include a bronze sleeve bearing with a length to shaft diameter ratio of at least 3:1 labyrinth – type sand slinger. The inter-connector shall completely enclose the upper motor end bell to protect the coupling and motor seal from abrasives. The inter- connector shall include a suction screen which has a net open area at least four time the area of the eye of the impeller. The screen shall be made of corrosion resistant material. Surface Plate (pump base) shall be made of fabricated steel. It shall rigidly support the total weight of the motor, bowl assembly, column pipe, cable and column of water. The cable outlet shall be designed to prevent entry of foreign matter into the well and shall be equipped with a cable seal. Drop Pipe threaded and coupled, shall conform to American Standard tapered pipe thread specifications. The pipe shall be sized so that flow velocities are not less than 4 feet per second nor more than 15 feet per second. The drop pipe may be furnished in random lengths. Submersible Cable shall be sized to limit the voltage drop of 5% at the motor’s terminals. Three (3) separate conductors shall be furnished. Each conductor shall be jacketed or the conductors may be included in a single jacketed assembly. The conductor insulation shall be water and oil resistant, suitable for continuous immersion. The length of the cable to be furnished shall be sum of (a) total pump setting, including bowl unit (b) plus one foot for each 50 feet of setting to compensate for possible twist or sag during installation, (c) plus additional length to extend from the surface plate to the pumping plant panel. The cable will be suitably supported from the column. All cable fittings and terminals shall be water tights at the pressure encountered in the application. Motor Control mounted in an indoor type NEMA-1 cabinet shall include: Hand-off automatic selector switch, start-stop push button, standard magnetic contractor and three ambient compensated adjustable ambient compensated quick-trip overload relays suitable for submersible pump motor service.

2.2 MEASUREMENT AND PAYMENT

The submersible deepwell pumps including accessories shall not be measured separately

since it will form part of the Pay-item 3.1 (Deepwell Development).

******