geotechnical report 03-1

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Geotechnical Exploration and Evaluation Report

Health Clinic Building

Florida

Date:-_____________

CLIENT

The General Services Administration (GSA) of

Atlantic City, Florida



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The General Services Administration (GSA), Our Ref:

Atlantic City, Date:

Florida

Attention: The Manager

Subject: Geotechnical Exploration and Evaluation Report of

Health Clinic Building, Florida

Dear Sir,

I am submitting the final geotechnical exploration and

evaluation report of your proposed project of health clinic

building, Florida. The report includes the recommended

foundation type and design based upon the field and laboratory

testing.

I hope that the investigation results presented in this report

will provide all the necessary information for the construction

of the subject building.

It is pleasure to provide services to you upon your request. If

you have any problem please don’t hesitate to call for any kind

of assistance.

Yours Truly,

(Student Name)



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Table of Contents

1. INTRODUCTION 3

2. INVESTIGATION PURPOSE 3

3. GEOTECHNICAL EXPLORATION SCOPE 3

4. SUBSOIL STRATIFICATION 4

5. FIELD TEST 5

6. FOUNDATION DESIGN CONSIDERATION 5

7. ENGINEERING RECOMMENDATIONS 7

8. INSPECTION AND MONITORING 8

9. SUMMARY OF RECOMMENDATIONS 8

10. REFERNCE 8

11. APPENDIX 9



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1. INTRODUCTION

The site for Health Clinic Building, Florida was explored

through 6-boreholes maximum drilled up to 7.62 m depth. The site

is located near the Government Centre Florida and is almost at

road level. This detailed report presents the field testing for

geotechnical investigation and recommendation for foundation

design of the proposed project with the following information.

Project : Health Clinic Building

Client : The General Services Administration (GSA) of

Atlantic City

Location : Florida

Site Area : 8,825 m2

Height of building : 9.14 m

No of Floor : 02

Type of Construction : Reinforced Cement Concrete

2. INVESTIGATION PURPOSE

The main purpose of the report presents description of the site,

a general geotechnical assessment of the project area, details

of the investigation performed and an appreciation of the

subsurface conditions as well as recommendations and conclusions

with respect to the foundation design for the proposed structure

based on the investigation results. The report also includes

recommendations on earthwork including grading, excavation, fill

and compaction.

3.

GEOTECHNICAL EXPLORATION SCOPE

The program of investigation comprised of following field and

laboratory testing;

Drilling of 06 Nos. bore holes of 50 mm diameter to a depth

of 7.62 m from, the respective borehole levels, using 63.5

kg weight using Cable tool Percussion method

Performance of related field test of SPT

Collection of representative disturbed & undisturbed

subsoil samples during soil exploration

Conducting various Laboratory tests

Evaluation of Field & Laboratory test results

Technical Report with recommendations of suitable

type/depth of foundation & safe bearing capacity



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Fieldwork was initiated on 25/03/2008 and was accomplished

on 31/03/2008.

4. SUBSOIL STRATIFICATION

The site was explored through 6-boreholes maximum drilled up to

7.62 m depth from the respective existing levels. The subsoilstrata are explained as below:

BH-1

00.00 - 01.80 m = Grey Silty Sand With Some Shells

01.80 - 04.60 m = Black Decomposed Organic Material

04.60 - 07.62 m = Tan Fragmented Limestone

BH-2

00.00 - 01.80 m = Sand With Fragmented Limestone

01.80 - 02.43 m = Gray Silty Sand With Organics And Shell


04.60 - 06.10 m = Gray Silty Sand And Organics


BH-3

00.00 - 00.61 m = Tan Silty Sand With Trace Fragmented

Limestone

00.61 - 01.22 m = Gray Silty Sand With Trace Shells


03.05 - 06.10 m = Black Decomposed Organic Material And Sand

06.10 – 07.62 m = Tan Fragmented Limestone

BH-4

00.00 - 00.61 m = Brown Sand With Trace Fragmented Limestone

00.61 - 01.82 m = Fragmented Limestone And Limestone


02.43 - 03.05 m = Gray Silty Sand And Shells


04.58 – 06.10 m = Gray Silty Sand With Some Shells




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BH-5

00.00 - 00.61 m = Sand With Trace Fragmented Limestone

00.61 - 01.22 m = Gray Sand With Fragmented Limestone

01.22 - 01.83 m = Tan Fragmented Limestone And Limestone


04.60 - 06.10 m = Gray Silty Sand And Shells


BH-6

00.00 - 02.43 m = Gray Silty Sand With Shell


04.60 - 06.10 m = Gray Silty Sand With Traces Shells


Groundwater-LEVEL

Ground water was come upon at depths ranging from 0.61-1.52 m

from the explored ground level.

5. FIELD TEST

STANDARD FENETRATION TESTS

Standard penetration test (SPT's) is performed on a regular

basis at 15 cm intervals up to the investigated depth in

accordance with the drilling manual specified in ASTM D-1586.

The test was carried out using a manual drop hammer assembly,

which utilizes a manual trip mechanism to release the weight all

in accordance with ASTM D-1586. Results are presented on

borehole logs appendix B figure 03 to figure 09.

6. FOUNDATION DESIGN CONSIDERATION

PILE FOUNDATIONS

Alternatively, pile foundation can be used instead of the

shallow foundations. Bored cast in situ or continuous flight

auger piles are recommended to be used. Table-1 gives the

working loads for piles installed at a pile toe level of H into

Limestone layers. Thus, the net (effective) length of the pile

is (Y) m given in Table-1.



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Table-01 (Working Loads for Piles)

These working loads are functions of both point (bearing)

resistance and skin friction and are estimated based on the “N”

values as well as the unconfined compressive strength of the

rock cores extracted from various depths of the boreholes

drilled. Moreover, the resulting pile capacities are compared

with structural capacities of each pile and taking into

consideration the compressive strength of the specified

concrete.

Even though the minimum value of the concrete compressive

strength of 30N/mm2 is allowed for the design of piles, the

concrete to be specified hereby is recommended to be of high

strength. For tall structures, a stiff raft foundation (Rite

Cap) has to be considered for the design of the pile system so

as to resist the differential and total settlement due to the

huge vertical and lateral forces (such as wind & earthquake).

The above working loads allow for a safety factor of at least

2.5.

The loads were calculated based on the method outlined in the

reference “Foundation design and construction” by Tomlinson.

It may be noted that the above recommended pile working load

capacities are tentative and hence these values should be

confirmed by carrying out pile load tests. Piling contractors

shall be contacted to confirm the working loads for their

respective system.

Every pile must be tested for its integrity (quality and

homogeneity) by carrying out non- destructive tests like sonic

test method. This is necessary to check out the defects or

damages (if any) which may occur after installation of piles dueto the lateral impacts, movements, soil instability and others.

Care should be taken into account during installation of piles

in such case good interactions between the concrete (or grout)

and the soil/rock are ensured in order to mobilize optimum

friction. Moreover, no disturbance shall be caused to the end

bearing strata so as to cause no excessive settlement under

initial loading.



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The recommended optimal spacing (S) between clustered piles is

in the order of (2.5 to 3.5 Diameter of the pile-C/C) for

vertical loads, such that: S > 76 cm tor Friction Piles

and S > 60 cm for Point Load Piles. Larger pile spacing is

usually more efficient for groups carrying lateral and/or

dynamic loads.

7. ENGINEERING RECOMMENDATIONS

During the construction measures should be taken as piling is a

critical activity and for the long stability of structure, it is

recommended to follow such measures.

The ground water table reported is expected to vary subject

to seasonal variations or any dewatering process in thevicinity. Hence it is advisable to install a standpipe

Piezometer and monitor the ground water table at regular

intervals until it was established that the water level in

borehole had reached equilibrium. At the time of construction

it shall be made sure that the excavation levels for

foundations are at least 0.3m above the ground water table so

that compaction process at the excavated level can be

properly carried out to the required degree.

For excavations deeper than 2.0m, suitable side protections

have to be ensured so that the excavation shall not pause athreat to the personnel working on the site or cause any

damage to nearby existing buildings or roads.

While carrying out dewatering, it shall be ensured that no

excessive settlement is caused to the nearby structures and

the process shall be carried out in stages. Moreover,

suitable precautions have to be taken especially in areas

with weak strata.

In case there is an existing structure, which is waiting for

demolition, and the soil investigation has to be carried out

outside the existing structure it is advisable to sink one or

two more boreholes after demolition to confirm the bearing

pressure.

It is advisable to keep the foundations at least 1.0m below

the finished ground level so that any future excavations for

service lines may not undermine the foundations.



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8. INSPECTION AND MONITORING

At the time of pile foundation construction, this office shall

be contacted to carry out compaction, plate load or other tests

if recommended in our report at random locations selected by us

in which case only a letter of confirmation can be issued for

the Safe Bearing Pressure and foundation levels. In case ofpiles, this office shall be contacted for pile integrity tests

without which a confirmation letter cannot be issued.

9. SUMMARY OF RECOMMENDATIONS

Type of Foundation : Pile Foundation

Depth of Pile : 6.5 m

Size of Pile : 0.8 m diameter

Shape of Pile : Circular

Material : RCC 30MPA

Bearing Pressure : 2050 kN

10. REFERNCE

Braja M. Das, "Principles of Foundation Engineering ",Third

Edition, PWS Publishing company

Joseph E Bowles, "Foundation Analysis and Design ", Fourth

Edition, MeGraw Hill International Edition

Joseph E Bowles, "Physical and Geotechnical Properties of

soils " Second Edition, MeGraw Hill International Edition

MJ Tomlinson, Foundation Design and Construction ", Fifth

Edition, Longman Scientific & Technical

Hsai - Yang Fang, "Foundation Engineering Handbook ", Second

Edition, Van Nostrand Reinhold

BS 5930:1999, “Code of Practice for Site Investigation "



Page | 9

11. APPENDIX

Tables (Appendix A)

Bore Hole Logs figures (Appendix B)



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APPENDIX - A

Table-2

Calculation of Pile Length

The ultimate bearing capacity of pile is calculated by following formula

2

4

2

145tan

2

2

Dπ

A

AqQ

πDL A

qαβ f

A f Q

QQQ

tip

tiptip

s

uc

s friction

tip frictionult

N

q N q uctip



Page | 11

APPENDIX - B

Figure -01: Site Plan



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Figure -02 (a) : Legends



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Figure -02 (b) : Legends



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Figure -03: Test bore log B-1



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Figure -09: Multiple Boring Profiles

geotechnical report 03-1

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