sec habitat asoka 280911
TRANSCRIPT
8/4/2019 SEC Habitat Asoka 280911
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1.1
New Construction Techniques for M odern Housing Schemes
New Construction
Techniques for ModernHousing Schemes
Asoka Perera
Professor of Civil Engineering
Department of Civil Engineering
University of Moratuwa
1.2
New Construction Techniques for Modern Housing Schemes
• Background
– Sri Lanka’s construction industry is yet to bebenefited from technologies developed for housing
– Small scale applications are visible but largely theconstruction technology is reinforced concrete,bricks, blocks and other traditional methods.
– However many other countries have implementednew housing technologies and getting the benefits.For example Government of Thailand have decidedto use pre-cast concrete methods to constructmore than 500,000 housing units to solve thehousing problem.
– Similarly in India the use of new methods haveincreased.
– Generally new methods are cost effective, fast,better appearance, better planned settlements anddurable.
OVERVIEW
1.3
New Construction Techniques for M odern Housing Schemes
OVERVIEW
1.4
New Construction Techniques for Modern Housing Schemes
OVERVIEW
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1.5
New Construction Techniques for M odern Housing Schemes
OVERVIEW
1.6
New Construction Techniques for Modern Housing Schemes
OVERVIEW
1.7
New Construction Techniques for M odern Housing Schemes
OVERVIEW
1.8
New Construction Techniques for Modern Housing Schemes
OVERVIEW
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1.9
New Construction Techniques for M odern Housing Schemes
• The main pitfall – Many believe alternative materials or methods is
the way to reduce cost or to increase speedcompletely forgetting the design aspects.
– The design aspects are very poorly addressed orcompletely ignored due to the fact thatArchitects, Structural Engineers and ServiceEngineers need to work as a team. Howevermain cost savings are in the area of design.
– It is no doubt that new materials and methodscan be cost effective on top of the designaspects. Further alternative materials andmethods can address some pressing problemssuch shortage of river, shortage of skilled labour(or high cost) etc.
HOUSING TECHNOLOGIES :OVERVIEW
1.10
New Construction Techniques for Modern Housing Schemes
• Three methods
–Design methods, optimization programs etc.Structural Design optimization is a goodexample.
– Alternative construction materials. Materials
such compressed earth blocks, fly ash blocksare good examples.
– New construction methods. New slabconstruction methods, Pre-cast concrete
methods, Ferrocement methods
HOUSING TECHNOLOGIES :OVERVIEW
1.11
New Construction Techniques for M odern Housing Schemes
HOUSING TECHNOLOGIES :OVERVIEW
Tec hnology P ossible Cost
savings
Implementation Challenges
1. D esign
methods
Structural Design
Services design
such as
electrical,
plumbing
Architectural
Design
Up to 30% savings
Up to 20% savings
Up to 20% savings
1. More design work
2. No additional fee, in fact the fee could get
reduced
3. Lack of confidence
4. Lack of familiarity with design methods such as
masonry design.
5. Naturally would like to be extra safe
6. Bill is paid by the client
7. No mechanism to check or to challenge the
efficiency of the design. Very common system
character
8. May require the use of advance methods such as
value analysis – A technique use USA military.
9. Getting and compiling technical information is
difficult.
10. Most popular may not the best.
11. Similar reasons of structural design.
12. Most difficult area for cost applications.
13. People buy Maruti cars as well as Benz cars
1.12
New Construction Techniques for Modern Housing Schemes
HOUSING TECHNOLOGIES :OVERVIEW
Technology Possible Cost
savings
Implementation Challenges
1.Alternative Construction
Materials
Compressed Earth Blocks(CEB)
Waste related products such
as fly ash blocks
UPVC
Cement tiles
Up to maximum of
20% cost savings.
Generally claimedas cost effective or
appear to be cost
effective but not
necessarily.
1.Compliance with existing standards.
Fore example CEB to comply with
BS5628.
2.Lack or non-existence of standardsparticularly for manufacture.
3.General resistance to new materials.
4.Lack of knowledge / information on
the new material.
1.New Construction
methods
Ex. Pre-cast concrete panels
New floor systems
Interlocking blocks
Rat-Trap Bond method
Up to a maximum of
20%
1. Similar to new materials
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1.13
New Construction Techniques for M odern Housing Schemes
• Three methods
– Most cost effective design method. For
example a masonry design could be 30% costeffective than reinforced concrete framearrangement. On the other hand for a buildingof 8 storeys reinforced concrete frame buildingcould be more cost effective than a masonrydesign.
– Cost optimization within a design. Costoptimization can be done to find out the mosteconomical steel and section arrangementconsidering the prices of concrete, steel andformwork.
– Use of value analysis for design of servicessuch as electrical work, plumbing etc.
HOUSING TECHNOLOGIES :DESIGN METHODS
1.14
New Construction Techniques for Modern Housing Schemes
• Most Cost effective Design method
– This could explain best with anexample. For example any house of twostorey and above can be taken. Theexample was taken form Tsunamihousing project in Ratmalana. Eachblock is consist of 8housing units andfour storeys
HOUSING TECHNOLOGIES :DESIGN METHODS
1.15
New Construction Techniques for M odern Housing Schemes
HOUSING TECHNOLOGIES :DESIGN METHODS
1.16
New Construction Techniques for Modern Housing Schemes
HOUSING TECHNOLOGIES :DESIGN METHODS
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1.17
New Construction Techniques for M odern Housing Schemes
• Most Cost effective Design method
– The initial arrangement was typicalreinforced concrete frame buildingswith independent footings with plinthbeams, columns, beams and slabs.Table below shows the arrangementcost comparisons with masonry loadbearing wall structure.
HOUSING TECHNOLOGIES :DESIGN METHODS
1.18
New Construction Techniques for Modern Housing Schemes
HOUSING TECHNOLOGIES :DESIGN METHODS
Element
Normal RC Design Masonry Design
Total Cost Total Cost
Footings in foundations 346,546.0 217,338.0
Plinth Beams 104,591.0 71,884.0
Rubble masonry infoundation 79,650.0 223,680.0
Columns 467,265.0 84,460.0
Beams 759,133.0 0.0
Walls 1,040,480.0 1,075,480.0
TOTAL 2,797,665.0 1,672,842.0
Net Saving 1,124,823.0
Saving % 40.2%
Net saving of the project 53,991,504.0
Total Estimate 429,600,000.0
Saving of the project % 12.6%
1.19
New Construction Techniques for M odern Housing Schemes
• Elemental optimum Design :Example froma RC slab
–
Slab also an expensive element in buildings.The optimum slab thickness is the one justsatisfies the deflection requirement and bestreinforcement arrangement is the one justsatisfies the bar spacing requirement (crackcontrol). However when spans becomes larger
the strength requirements supersedes theabove requirements.
HOUSING TECHNOLOGIES :DESIGN METHODS
1.20
New Construction Techniques for Modern Housing Schemes
• Elemental optimum Design :Examplefrom a RC slab
HOUSING TECHNOLOGIES :DESIGN METHODS
Normal RC Design Optimum DesignTotal Cost Total Cost
Slab - Concrete 248,500.0 248,500.0
Slab - Reinforcement 264,504.0 186,960.0
Slab - Formwork 203,550.0 203,550.0
TOTAL 716,554.0 639,010.0
Saving 77,544.0
Saving % 10.8%
Total project cost saving 3,722,112.0
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1.21
New Construction Techniques for M odern Housing Schemes
• Earth Related Technologies
– Compressed Stabilized Earth blocks
– Adobe Blocks
– Rammed Earth
• Other new methods
– Straw bale method
– Bamboo related methods
– Waste related methods
• Interlocking blocks
– Concrete blocks
– Polystyrene interlocking blocks
ALTERNATIVE CONSTRUCTION MATERIALS
1.22
New Construction Techniques for Modern Housing Schemes
• The use of compressed earth blocks inSri Lanka
– First attempt in 1960’s with CINVA rammachines
– Some houses were constructed in Colombo,Batticaloa etc.
– Second attempt in 1980’s – NBRO building,
some in Gampaha
– In 1990’s by University of Moratuwa – morethan 2000 houses.
– There is growth of the application
ALTERNATIVE CONSTRUCTION MATERIALS :EARTH CONSTRUCTIONS
1.23
New Construction Techniques for M odern Housing Schemes
• The use of compressed earth blocks in SriLanka
• There are three manufacturers now.
– One well established and have fairly good demand.The start was very difficult and project in Horanahelped to get established.
– One has just commenced the production usingHydraform machine – a good machine but blocksseem expensive
– One in Galle – planning to introduce plain blocks aswell as interlocking blocks using Hydraformmachine.
– Some NGOs
– Small scale manufacturers
ALTERNATIVE CONSTRUCTION MATERIALS :EARTH CONSTRUCTIONS
1.24
New Construction Techniques for Modern Housing Schemes
• The use of compressed earth blocks inother countries
– India, There is wide usage mainly in Kerala,
Tamil Nadu and other places – Thailand – Initiatives of Habitec Centre
– Australia
– USA
– Germany
– France
ALTERNATIVE CONSTRUCTION MATERIALS :EARTH CONSTRUCTIONS
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1.25
New Construction Techniques for M odern Housing Schemes
ALTERNATIVE CONSTRUCTION MATERIALS :EARTH CONSTRUCTIONS
1.26
New Construction Techniques for Modern Housing Schemes
ALTERNATIVE CONSTRUCTION MATERIALS :EARTH CONSTRUCTIONS
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New Construction Techniques for M odern Housing Schemes
ALTERNATIVE CONSTRUCTION MATERIALS :EARTH CONSTRUCTIONS
1.28
New Construction Techniques for Modern Housing Schemes
SOIL BLOCK MACHINES
Soil:cement block machine Nature of projects Cost of Machine
1. CINVA ram machine
This is a very simple machine. Can be
transported from one project to the
other very easily. However
machine breaks quite often.
Suitable for self-help rural projects.
Good blocks can be made with
good quality controlling
measures
Rs. 15,000 (Normal
block)
Rs. 35,000
(Interlocking
block)
1. Auram Machines
Very good manual machines
manufactured in India. Two sizes
of machines are available. Moulds
are available to manufacture normal
blocks and interlocking blocks
Suitable to general building projects.
Machine ideal for setting-up of
small-scale block manufacturing
yards too. The small machine
very suitable for the construction
of rural buildings
Rs. 170,000 (with all
options – three
sizes of blocks)
Rs. 90,000 (small
machine)
3.0 Automated hydraulic machines Large scale building projects and
setting-up of block
manufacturing yards
Rs. 2.0 million –
Medium
machines
Rs. 12 to 50 million
large machines
form USA and
China
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New Construction Techniques for M odern Housing Schemes
SOIL BLOCK MACHINES
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New Construction Techniques for Modern Housing Schemes
SOIL BLOCK MACHINES
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New Construction Techniques for M odern Housing Schemes
SOIL BLOCK MACHINES
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New Construction Techniques for Modern Housing Schemes
SOIL BLOCK MACHINES
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New Construction Techniques for M odern Housing Schemes
SOIL BLOCK MACHINES
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New Construction Techniques for Modern Housing Schemes
SOIL BLOCK MACHINES
1.35
New Construction Techniques for M odern Housing Schemes
• Standards for Earth Construction
– Sri Lanka now has a standard forCompressed StablizedEarth Blocks
–
The use of provisions given in BS5628 –Standard for masonry, this will cover wall
construction but not the manufacture ofearth blocks but does not cover themanufacture of blocks
– There is an Australian code of practice
– There is an appendix to the building code ofUSA
ALTERNATIVE CONSTRUCTION MATERIALS :EARTH CONSTRUCTIONS
1.36
New Construction Techniques for Modern Housing Schemes
• The Indian for manufacture ofcompressed earth blocks
– Specify the sizes of blocks, 300X140X100,
240X240X100, 250X110X100 – Specify the compressive strength expected
from blocks, 2.5N/mm2 to 5.0N/mm2
– General statements on machines for block
manufacture
– General statements on manufacturingprocess
ALTERNATIVE CONSTRUCTION MATERIALS :EARTH CONSTRUCTIONS
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1.37
New Construction Techniques for M odern Housing Schemes
• The use of provisions in BS5628
– Full scale wall panels and blocks need to be
tested. – Results were observed at
• Load deformation behaviour of wall panels;
• Stress at 1st crack; and
• Stress at failure
ALTERNATIVE CONSTRUCTION MATERIALS :EARTH CONSTRUCTIONS
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New Construction Techniques for Modern Housing Schemes
ALTERNATIVE CONSTRUCTION MATERIALS :EARTH CONSTRUCTIONS
Physical characteristics Specified limits
Dry density
Total water absorption
>1750 kg/m3
< 1 5 %
Dry compressive strength
Grade1: > 6 .0N/mm2
Grade2 : >4.0up to6.0N/mm2
Grade3 : 2.8 upto4.0N/mm2
(not applicable for interlocking blocks)
Wet compressive strength
Grade1: >2 .4N/mm2
Grade2 : >1.6up to2.4N/mm2
Grade3 : >1.2up to1.6N/mm2
(notapplicable for interlocking blocks)
Flexural strength (bending strength) > 0.5 N/mm2
Pitting depth (Erosion resistance)< 10 mm
Linear expansion of block upon saturation with water< 0.10%
1.39
New Construction Techniques for M odern Housing Schemes
ALTERNATIVE CONSTRUCTION MATERIALS :EARTH CONSTRUCTIONS
1.40
New Construction Techniques for Modern Housing Schemes
• The Australian code of practice
– It is available in the CD given
– Let us go through the code
ALTERNATIVE CONSTRUCTION MATERIALS :EARTH CONSTRUCTIONS
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1.41
New Construction Techniques for M odern Housing Schemes
• Manufacture of Soil cement blocks
ALTERNATIVE CONSTRUCTION MATERIALS :EARTH CONSTRUCTIONS
1.Extraction of soil; 2 . Transportation of soil;
3.Screening of soil; 3. Measuring of soil and
cement;
4. Dry mixing of soil and
cement;
5. Adding of water for humid
mixing;
6. Moulding using a
machine;
7. Curing of soil:cement
blocks; and
8. Storing of blocks.
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New Construction Techniques for Modern Housing Schemes
ALTERNATIVE CONSTRUCTION MATERIALS :EARTH CONSTRUCTIONS
1.43
New Construction Techniques for M odern Housing Schemes
• We could use
– SLS Standards –SLS1382
– Machine manufacturers manuals
– Published manuals – a good one in the CD – Let us go through a good manual –
Published by GATE
ALTERNATIVE CONSTRUCTION MATERIALS :EARTH CONSTRUCTIONS
1.44
New Construction Techniques for Modern Housing Schemes
• Block Types
– Different types are available
ALTERNATIVE CONSTRUCTION MATERIALS :EARTH CONSTRUCTIONS
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New Construction Techniques for M odern Housing Schemes
ALTERNATIVE CONSTRUCTION MATERIALS :EARTH CONSTRUCTIONS
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New Construction Techniques for Modern Housing Schemes
ALTERNATIVE CONSTRUCTION MATERIALS :EARTH CONSTRUCTIONS
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New Construction Techniques for M odern Housing Schemes
ALTERNATIVE CONSTRUCTION MATERIALS :EARTH CONSTRUCTIONS
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New Construction Techniques for Modern Housing Schemes
ALTERNATIVE CONSTRUCTION MATERIALS :EARTH CONSTRUCTIONS
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1.57
New Construction Techniques for M odern Housing Schemes
• Rammed Earth method
– Houses can be constructed with full
rammed earth methods – It is much easier to first erect concrete
columns and then to rammed earth wall
using slip form method
– Probably the best may be to first erectreinforced earth columns using interlockingblocks and then to do the rammed earth
walls
– Forms could be purchased fromgovernment factory and private suppliers
ALTERNATIVE CONSTRUCTION MATERIALS :EARTH CONSTRUCTIONS
1.58
New Construction Techniques for Modern Housing Schemes
• Rammed Earth method
ALTERNATIVE CONSTRUCTION MATERIALS :EARTH CONSTRUCTIONS
1.59
New Construction Techniques for M odern Housing Schemes
• Rammed Earth method
ALTERNATIVE CONSTRUCTION MATERIALS :EARTH CONSTRUCTIONS
1.60
New Construction Techniques for Modern Housing Schemes
• Rammed Earth method
ALTERNATIVE CONSTRUCTION MATERIALS :EARTH CONSTRUCTIONS
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1.61
New Construction Techniques for M odern Housing Schemes
• Rammed Earth method
ALTERNATIVE CONSTRUCTION MATERIALS :EARTH CONSTRUCTIONS
1.62
New Construction Techniques for Modern Housing Schemes
• Rammed Earth method
ALTERNATIVE CONSTRUCTION MATERIALS :EARTH CONSTRUCTIONS
1.63
New Construction Techniques for M odern Housing Schemes
• Rammed Earth method
ALTERNATIVE CONSTRUCTION MATERIALS :EARTH CONSTRUCTIONS
1.64
New Construction Techniques for Modern Housing Schemes
• Rammed Earth method
ALTERNATIVE CONSTRUCTION MATERIALS :EARTH CONSTRUCTIONS
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1.65
New Construction Techniques for M odern Housing Schemes
• Very widely used in India
• This is basically brick on edge
ALTERNATIVE CONSTRUCTION M ETHODS : RAT-TRAP BOND METHOD
1.66
New Construction Techniques for Modern Housing Schemes
• Very widely used in India
• This is basically brick on edge
ALTERNATIVE CONSTRUCTION METHODS : RAT-TRAP BOND METHOD
1.67
New Construction Techniques for M odern Housing Schemes
• Wide range of floor slabs are nowavailable for housing
– In Sri Lanka ICC, NERD, University of
Moratuwa – Habitech centre has curved plans and
integrated concrete slab
ALTERNATIVE CONSTRUCTION METHODS :FLOOR SLABS
1.68
New Construction Techniques for Modern Housing Schemes
ALTERNATIVE CONSTRUCTION METHODS :FLOOR SLABS
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1.69
New Construction Techniques for M odern Housing Schemes
• Pre-cast concrete door and windowframes
• Roof items – Pre-cast purlins• Steel roof structures for housing – you
will get more details during site visits
• Steel forms for staircases
• There are many more from Habiteccentre
ALTERNATIVE CONSTRUCTION M ETHODS :OTHER METHODS
1.70
New Construction Techniques for Modern Housing Schemes
• Formwork systems for concrete wallsand slabs
• Polystyrene forms for walls• Sprayed concrete on polystyrene
boards
• Wide range of products are available forabove methods
ALTERNATIVE NEW CONSTRUCTION M ETHODS
1.71
New Construction Techniques for M odern Housing Schemes
• Formwork system – MASCON fromCanada – Similar systems are availablefrom Germany, India etc.
ALTERNATIVE NEW CONSTRUCTION M ETHODS
1.72
New Construction Techniques for Modern Housing Schemes
• Formwork system – MASCON fromCanada – Similar systems are availablefrom Germany, India etc.
ALTERNATIVE NEW CONSTRUCTION M ETHODS
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1.73
New Construction Techniques for M odern Housing Schemes
• Formwork system – MASCON fromCanada – Similar systems are available
from Germany, India etc.
ALTERNATIVE NEW CONSTRUCTION M ETHODS
1.74
New Construction Techniques for Modern Housing Schemes
• Formwork system – MASCON fromCanada – Similar systems are available
from Germany, India etc.
ALTERNATIVE NEW CONSTRUCTION M ETHODS
1.75
New Construction Techniques for M odern Housing Schemes
• Formwork system – MASCON fromCanada – Similar systems are availablefrom Germany, India etc.
ALTERNATIVE NEW CONSTRUCTION M ETHODS
1.76
New Construction Techniques for Modern Housing Schemes
• Formwork system – MASCON fromCanada – Similar systems are availablefrom Germany, India etc.
ALTERNATIVE NEW CONSTRUCTION M ETHODS
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1.77
New Construction Techniques for M odern Housing Schemes
• Formwork system – MASCON fromCanada – Similar systems are available
from Germany, India etc.
ALTERNATIVE NEW CONSTRUCTION M ETHODS
1.78
New Construction Techniques for Modern Housing Schemes
• Formwork system – MASCON fromCanada – Similar systems are available
from Germany, India etc.
ALTERNATIVE NEW CONSTRUCTION M ETHODS
1.79
New Construction Techniques for M odern Housing Schemes
• Polystyrene forms for walls availableform USA, Australia etc.
• Generally expensive
ALTERNATIVE NEW CONSTRUCTION M ETHODS
1.80
New Construction Techniques for Modern Housing Schemes
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1.81
New Construction Techniques for M odern Housing Schemes
1.82
New Construction Techniques for Modern Housing Schemes
1.83
New Construction Techniques for M odern Housing Schemes
• Let us look at compressed earth blocks
PROCUREMENT OF TECHNOLOGY AND COST SAVINGS
1.84
New Construction Techniques for Modern Housing Schemes
• Design methods
• Alternative construction materials
• Alternative construction methods
• Cost of setting out
SUMMARY