Research Topic - epsmg.jkr.gov.myepsmg.jkr.gov.my/images/4/44/Instrumented_Static_Load_Test... ·...

Research Topic

Analysis of Instrumented Pile

Load Test Results

2005

JKR (CPKA) Research Representatives:

Dr. H.M. Abdul Aziz Bin K.M. Hanafiah

Ir. Mohamad Nor Bin Omar

Nor Fardzilah Bt. Abdul Rahman

Overview

Routine Static Load Test Load- Settlement at Pile Head Shaft Friction in Different Layers Shaft Friction and End Bearing Optimise Pile Lengths & Behaviour

Pile Instrumentation Strain Gauges Extensometers Pressure Cells

Objective

Pile Instrumentation Scheme

Review Interpretation procedures

Review Analysis Methodology

Load-Transfer Method

Analyse Instrumented Test Results

Derive Design Parameters & Load-transfer Curves – Kenny Hill, Old Alluvium

Pile Instrumentation

Strain Gauges

Vibrating Wire – reliable, effective tool

Sensor output – frequency

Types – Concrete embedment type, Sister bar strain gauge (robust)

Extensometers

Mechanical Rod Type, Retrievable Extensometers

Instrumented Pile Load Test Data

Projects –

Gerbang Selatan Bersepadu – 13 nos.

Kompleks Makamah – 3 nos.

Jalan Kelang Lama – 1 no.

Geology

Kenny Hill – Kompleks Makamah & Jln. Kelang Lama

Old Alluvium – Gerbang Selatan Bersepadu

Instrumented Pile Load Test Data

No. SITE LOCATION INSTRUMENTED PILE NUMBER 1 Gerbang ICW-01, Pile PTP1 (750mm dia) 2 ICW-01, Pile PTP2 (1000mm dia) 3 ICW-01, Pile PTP3 (1000mm dia) 4 ICW-01, Pile PTP4 (750mm dia) 5 ICW-01, Pile PTP5 (750mm dia) 6 Land Approach, Pile PC3/4 (1200 mm dia) 7 CIQ Main Office, Pile PTP1 (1000 mm dia) 8 CIQ Main Office, Pile PTP2 (900 mm dia) 9 CIQ Main Office, Pile GTP3 (1000 mm dia) 10 CIQ Main office, Pile GTP 5 (1200 mm dia) 11 JB Sentral, Pile PTP1 (1200 mm) 12 Cable Stayed Bridge, Pile 31/W (1500 mm dia) 13 Cable Stayed Bridge, Pile 23/E (1500 mm dia) 14 Kompleks Makamah Pile ITP1 (750 mm) 15 Pile ITP2 (750 mm) 16 Pile ITP3 (750 mm) 17 Jalan Kelang Lama Pile PTP2 (1000 mm dia)

Kenny Hill Formation

Meta-sedimentary

Interbedded sandstones, shale/mudstone, quartzite & phyllite

Undergone intense weathering – thickness varies – parent material, geomorphology

GRADE 111/ 11

GRADE VI

GRADE V

GRADE IV

GRADE III

GRADE II

GRADE I

Old Alluvium

Continental deposits of SAND, CLAY & Boulder Beds of fluviate and shallow marine origin.

Base of this formation – 100m and 145m below sea level.

Load Deformation Analysis

Elastic Analytical Methods Mindlin’s equations – Poluos and Davis

Randolph and Wroth – closed form soln.

Numerical Methods – relatively complex Finite Element Method

Boundary Element Method

Load Transfer Method Load transfer characteristics should be known

Can be obtained from instrumented pile load tests

Generation of Load Transfer Curves

Usage of Instrumented Pile Load Test result

Assumption – Strain in steel = strain in concrete.

P = strain x Area x E

fsm = (Ptop – P bot)/pi x dia x length

Mid-shaft movement – linearly interpolated.

Process repeated for each head load.

Modulus Estimates

Fellenius (1989, 2001) proposed a method of first determining the tangent modulus from strain gauge measurements and then using it to determine the secant modulus. The stress at a plane is then equal to the secant modulus multiplied by the strain.

The procedure is based on the fact that, after the side shear on a shaft is fully mobilized and no longer changes with loading, the changes in stress and strain at the plane of the strain gauges reflect the composite modulus of the shaft at that loading.

One of the limitation of the method is the need to reach or exceed ultimate side shear values during the test. A second limitation is that the total strain at the plane of interest must reach at least 50 micro-strain and preferably more then 200 micro-strain (Hayes J and Simmonds T, 2003).

Modulus Estimates

The equation of the tangent line is: M = (dσ/dε) = Aε + B (1) which can be integrated to: σ = (A/2)ε2 + Bε (2) However, σ = Es ε (3) Therefore, Es = 0.5Aε + B where M = tangent modulus of composite material Es = secant modulus of composite material σ = stress (load divided by cross section area) ε = measured strain dσ = change of stress from one load increment to the next dε = change of strain from one load increment to the next A = slope of tangent modulus B = y-intercept of tangent modulus line

Strain

Stre

ss

Normalised Load Transfer Curves

Full mobilisation of the shaft resistance

fsc, Zsc selected

The shaft resistance and shaft displacement were normalised with fsc and Zsc and plotted.

Typical Results In Kenny Hill Formation

Project : Kompleks Mahkamah, Jalan Duta, Kuala Lumpur.

Instrumentation levels for Preliminary Test Pile ITP -2 (750mm dia.) @ GIL 14/C-D, Zone C (Left).

Pile length given ~ 9.0m from Existing Ground.

Test Pile ITP-2(750mm dia.)

SPT value, N (blows/30cm) RL 53.6m (Pile top)

0 20 40 60 80 100 120 140 160 180 200 0.0 RL 53.0m (Existing GL)

0.75m lvwsGt<v<l A I • [ RL 52.25m (Lev A)

1.0 A-9 Sensor 1a & tb

v3 2.0

~ 3.0 " 3.0m lvwsGt<v<IB I l::tl RL 50.0m (Lev B)

5 '-'4.0 A-9 Sensor 2a &2b 0:

I· ... ~ 3 4.5m

IVWSGievel I RL 48.5m (Lev C) ~

' = = ~5.0 ........

A-9 Sensor 3a &3b CJ)

I· 'i ' lvwsGievel I =

' 5.5m RL 47.5m (Lev D)

:~ .. ~6.0 A-9 Sensor 4a & 4b

.s:

~ [ .. IVWSGievel I ..Q 6.5m RL 46.5m (Lev E)

; ~.0 A-9 Sensor 5a &5b ~

50 IVWSGieveiF I • 7.5m RL 45.5m (Lev F)

8.0

8.5m IVWSGievel G I • I RL 44 .5m (Lev G)

9.0 Pile toe at 9.0 m deptlt (RL 44.0m)

10.0

Legend a denotes V ibrating W ire Strain Gauges

(4 no. Geokon VSM·4000 at each levels) 11.0 • denotes A-9 VW Extensometer anchored level

( 2 no. anchors per level) (S.I. Borehole NBH 1)

PLOT OF PILE TOP LOADS (kN) VS PILE TOP SETTLEMENT (mm)

FOR 1st & 2nd CYCLE OF MAINTAINED LOAD TESTING

0

500

1000

1500

2000

2500

3000

3500

4000

4500

5000

5500

6000

6500

7000

7500

8000

8500

9000

9500

10000

10500

11000

0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150

Pile Top Settlement (mm)

Pil

e T

op

Lo

ad

(k

N )

1st Cycle 2nd Cycle

Kompleks Mahkamah-PILE ITP2

y = -0.0059x + 25.354

0.00

5.00

10.00

15.00

20.00

25.00

30.00

35.00

40.00

45.00

50.00

0 100 200 300 400 500 600 700 800 900 1000

Micro-strain

Tang

ent M

odul

us (k

Pa)

Level A

Linear (Level A)

LOAD DISTRIBUTION CURVE FOR 1st CYCLE COMPUTED FROM

VWSGs TEST RESULTS

6411

5311

4914

2938

2293

1984

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

5.0

5.5

6.0

6.5

7.0

7.5

8.0

8.5

9.0

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500 6000 6500 7000

Loads ( kN)D

epth

bel

ow p

latfo

rm le

vel (

m)

P=313 kN P = 540 kN P= 754 kN P= 980 kN P = 1223 kN P = 1462 kN P=1726 kNP=1952 kN P=2197 kN P=2470 kN P=2678 kN P=2920 kN P=3158 kN P=3415 kNP=3737 kN P=3934 kN P=4238 kN P=4453 kN P=4741 kN P=4970 kN P=5224 kNP= 5436 kN P=5741 kN P= 5959 kN P=6182 kN P=6482 kN P=6629 kN P=7011 kN

LOAD DISTRIBUTION CURVE FOR 2nd CYCLE COMPUTED FROM

VWSGs TEST RESULTS

Kompleks Makamah - Pile ITP2- Load Distribution with Depth

10000

10000

8975

7543

7338

4482

3717

3614

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

5.0

5.5

6.0

6.5

7.0

7.5

8.0

8.5

9.0

0 1000 2000 3000 4000 5000 6000 7000 8000 9000 10000

Loads ( kN)

De

pth

be

low

pla

tfo

rm le

ve

l (m

)

P=667 kN P = 1037 kN P= 1537 kN P= 2086 kN P = 2524 kN P = 2985 kN P=3577 kNP=4070 kN P=4652 kN P=5130 kN P=5512 kN P=5994 kN P=6457 kN P=7013 kNP=7231 kN P=7430 kN P=7572 kN P=7759 kN P=8046 kN P=8252 kN P=8550 kNP=8760 kN P=9002 kN P= 9265 kN P=9526 kN P=9671 kN P=10000 kN

Kompleks Mahkamah - ITP2: Load Transfer Curves (cycle-2)

0

200

400

600

800

1000

1200

1400

0 10 20 30 40 50 60 70 80 90

Displacement Z (mm)

Mo

bilis

ed

Un

it S

haft

Resis

tan

ce (

kP

a)

Level A to BLevel B to CLevel C to DLevel D to ELevel E to FLevel F to G

Kompleks Mahkamah - Pile ITP2: Load Transfer Curves for base (cycle-2)

0.00

1000.00

2000.00

3000.00

4000.00

5000.00

6000.00

7000.00

8000.00

9000.00

0 10 20 30 40 50 60 70 80

Displacement Z (mm)

Mo

bilis

ed

Base S

haft

Resis

tan

ce (

kP

a)

Normalised Load Transfer Curves for Kenny Hill Formation

NORMALIZED LOAD TRANSFER CURVES FOR SHAFT

(KENNY HILL FORMATION)

0.00

0.20

0.40

0.60

0.80

1.00

1.20

0.00 0.50 1.00 1.50 2.00 2.50 3.00

Normalized Shaft Displacement (Zs/Zsc)

No

rma

lize

d S

ha

ft R

es

ista

nc

e (

fs/f

sc

)

(Zs/Zsc) ≤ 0.35 : fs/fsc = 2.19(Zs/Zsc)0.35 ≤ (Zs/Zsc) ≤ 1.0 : fs/fsc = 2.245(Zs/Zsc) - 1.28(Zs/Zsc) 2̂ 1.0 ≤ (Zs/Zsc) ≤ 1.35 : fs/fsc = 1.23 - 0.23(Zs/Zsc) (Zs/Zsc) ≥ 1.35 : fs/fsc = 0.95

NORMALIZED LOAD TRANSFER CURVES FOR BASE

(KENNY HILL FORMATION)

0.00

0.10

0.20

0.30

0.40

0.50

0.60

0.70

0.80

0.90

1.00

0.00 0.10 0.20 0.30 0.40 0.50 0.60 0.70 0.80 0.90 1.00

Normalized Base Displacement (Zb/Zbc)

No

rma

lize

d B

as

e R

es

ista

nc

e (

fb/f

bc

)

fb/fbc = (Zb/Zbc)^2.5


y = 2.3582x

0

50

100

150

200

250

300

350

400

450

500

0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150

SPT Value (N blows/300mm)

fsu

Ma

xim

um

(k

Pa

)

Typical Results in Old Alluvium

Gerbang Selatan Bersepadu: CIQ Piling Works At Bukit Cagar, Johor Bahru.

Instrumentation levels for test pile GTPS (1200mm dia.)

As-built Pile length ~ 34.1 from Existing Ground Level ofRL 3.9m

SPT value, N (blows/30cm)

0 20 40 60 80 100 120 140 160 180 200

l.Om

10 8 .5m

20

15

16

~ 13 20

20.5 m

25

26.5 m

\~ 30

3 1.0 m

~00

I "\"-120

33.5 HI

35

40 1.,-ll

(SJ. Boreh o le ABHl )

Test Pile GTPS (1200mm dia.)

r--r--, RL 4 .4m (Pile top)

RL 3.9m (Existing GL)

lvwsGtev d I RL 2 .9m (Lev A)

A-9 Sensor a & 1 b

lvwsGievdB I RL -4.6m (Lev B)

A-9 Sensor a & 2b

IVWSGiev d I • RL -1 6.6m(Lev C)

A-9 Sensor a & 3b

IVWSGievdD I • RL -22.6m (Lev D)

A-9 Sensor a & 4b

IVWSG levd E I 0 RL- 27.1m (Lev E )

A-9 Sensor ~a & 5b

"'lvw=:::s -::G:-:I:-ev-d701 I• _ • I RL -29.6m (Lev F)

~ile Toe Flat .Jack

Legend I!!

•

Pile toe at 3 4.1 m depth (RL- 30.2m )

denotes V ibrating VVire Strain G auges

(4 no. V SM-4000 at each levels)

denotes A-9 VW Extensometer anchored lev el

( 2 no. anchors per level)

PLOT OF PILE TOP LOADS (kN) VS PILE TOP SETTLEMENT (mm)

FOR 1st & 2nd CYCLE OF MAINTAINED LOAD TESTING

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

10000

11000

12000

13000

14000

15000

16000

17000

18000

19000

20000

21000

22000

0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75

Pile Top Settlement (mm)

Pile

To

p L

oa

d (

kN

)

1st Cycle 2nd Cycle

Gerbang CIQ Main Office-PILE GTP5

y = -0.0257x + 30.691

0.00

5.00

10.00

15.00

20.00

25.00

30.00

35.00

40.00

45.00

50.00

0 100 200 300 400 500 600Micro-strain

Ta

ng

en

t M

od

ulu

s (

kP

a)

Level ALinear (Level A)

LOAD DISTRIBUTION CURVE FOR 1st CYCLE COMPUTED FROM

VWSGs TEST RESULTS

84618461

6620

4666

3862

1832

242

0123456789

1011121314151617181920212223242526272829303132333435

0 2000 4000 6000 8000

Loads ( kN)D

epth

bel

ow p

latfo

rm le

vel (

m)

P=736 kN P = 1061 kN P= 1590 kN P= 2015 kN P = 2474 kN P = 3079 kN P=3496 kNP=4094 kN P=4463 kN P=5189 kN P=5609 kN P=6015 kN P=6536 kN P=7053 kNP=7528 kN P=8011 kN P=8461 kN

LOAD DISTRIBUTION CURVE FOR 2nd CYCLE COMPUTED FROM

VWSGs TEST RESULTS

1954319543

13416

10022

9079

7327

3705

0123456789

1011121314151617181920212223242526272829303132333435

0 2000 4000 6000 8000 10000 12000 14000 16000 18000 20000

Loads ( kN)D

epth

bel

ow p

latfo

rm le

vel (

m)

P=707 kN P = 1197 kN P= 1596 kN P= 2164 kN P = 2517 kN P = 3073 kN P=3545 kN P=3978 kNP=4734 kN P=5192 kN P=5762 kN P=6274 kN P=6781 kN P=7179 kN P=7505 kN P=7942 kNP=8563 kN P=9057 kN P=9527 kN P=10012 kN P=10477 kN P= 10973 kN P= 11395 kN P= 11854 kNP=12479 kN P=12935 kN P=13488 kN P=13955 kN P=14443 kN P=14932 kN P=15522 kN P=15964 kNp=16443 kN P=16907 kN P=17416 kN P=17951 kN P=18476 kN P=18938 kN P=19543 kN

Gerbang CIQ Main Office - GTP5: Load Transfer Curves (cycle 2)

0

50

100

150

200

250

300

350

0 10 20 30 40 50 60 70 80

Displacement Z (mm)

Mo

bilis

ed

Un

it S

haft

Resis

tan

ce (

kP

a)

Level A to BLevel B to CLevel C to DLevel D to ELevel E to F


(YOUNG ALLUVIUM FORMATION)

0.00

0.20

0.40

0.60

0.80

1.00

1.20

0.00 0.50 1.00 1.50 2.00


No

rmali

zed

Sh

aft

Resis

tan

ce (

fs/f

sc)

(Zs/Zsc) ≤ 0.20 : fs/fsc = 3.1(Zs/Zsc)0.20 ≤ (Zs/Zsc) ≤ 1.0 : fs/fsc = 0.55(Zs/Zsc) - 0.22(Zs/Zsc) 2̂ + 0.671.0 ≤ (Zs/Zsc) ≤ 1.30 : fs/fsc = 0.95 - 0.04(Zs/Zsc) (Zs/Zsc) ≥ 1.30 : fs/fsc = 0.90


(OLD ALLUVIUM FORMATION)

0.00

0.20

0.40

0.60

0.80

1.00

1.20

0.00 0.50 1.00 1.50 2.00 2.50 3.00


No

rmalized

Sh

aft

Resis

tan

ce (

fs/f

sc)

(Zs/Zsc) ≤ 0.2 : fs/fsc = 3.5(Zs/Zsc)0.2 ≤ (Zs/Zsc) ≤ 0.85 : fs/fsc = 0.3(Zs/Zsc)^2 - 0.02(Zs/Zsc) + 0.770.85 ≤ (Zs/Zsc) ≤ 1.4 : fs/fsc = 0.01(Zs/Zsc) + 0.98(Zs/Zsc) ≥ 1.40 : fs/fsc = 0.95

NORMALIZED LOAD TRANSFER CURVES FOR BASE

(OLD ALLUVIUM FORMATION)

0.00

0.10

0.20

0.30

0.40

0.50

0.60

0.70

0.80

0.90

1.00

0.00 0.10 0.20 0.30 0.40 0.50 0.60 0.70 0.80 0.90 1.00

Normalized Base Displacement (Zb/Zbc)

No

rma

lize

d B

as

e R

es

ista

nc

e (

fb/f

bc

)

fb/fbc = (Zb/Zbc)^1.2

Young Alluvium Formation

y = 4.2053x

020406080

100120140160180

0 5 10 15 20 25 30 35 40 SPT Value (N blows/300mm)

fsu

Maxim

um

(kP

a)

Old Alluvium Formation

y = 2.0541x

0102030405060708090

100

0 5 10 15 20 25 30 35 40 45 50 SPT Value (N blows/300mm)

fsu

Maxim

um

(kP

a)

Results and Discussion

Test Pile Results Gerbang Selatan Bersepadu

Yound Alluvium (N<15) – fsm = 40 kPa to 100 kPa

Old Alluvium (N = 20 to 100) – fsm = 50 to 200 kPa

Kompleks Makamah Grade IV (N>50) – fsm = 150 to 700 kPa

Jalan Kelang Lama Grade VI/V (N<50) – fsm = 40 kPa

Garde IV (N>50) – fsm = 100 to 440 kPa

Results

For piles in Old alluvium, end bearing – 0.01% to 2.33% of total capacity – end bearing negligble (34m to 60m long piles)

For short piles in KH (7m to 12m) – end bearing – 21% and 57% of total capacity.

For long pile in KH (24m), end bearing negligble.

Results

Correlation between SPT N Value and Maximum shaft resistance

Young Alluvium – fsu = 4.2N kPa

Old Alluvium – fsu = 2.0 N kPa

Kenny Hill – fsu = 2.3 N kPa (N < 150) fsu = 16 N½ ( N > 150)



For Zs/Zsc ≤ 0.35 :fs/fsc = 2.19 (Zs/Zsc)

For 0.35 ≤ Zs/Zsc ≤ 1.0 : fs/fsc = 2.245 (Zs/Zsc) – 1.28 (Zs/Zc)2

For 1.0 ≤ Zs/Zsc ≤ 1.35 : fs/fsc = 1.23 – 0.23 (Zs/Zsc)

For Zs/Zc ≥ 1.35 : fs/fsc = 0.95

For Base fb/fbc = (Zb/Zbc)2.5


Young Alluvium


For 0.2 ≤ Zs/Zsc ≤ 1.0 :fs/fsc = 0.55 (Zs/Zsc) – 0.22 (Zs/Zc)2 + 0.67

For 1.0 ≤ Zs/Zsc ≤ 1.30 :fs/fsc = 0.95 – 0.04 (Zs/Zsc)

For Zs/Zc ≥ 1.30 :fs/fsc = 0.90


Old Alluvium


For 0.2 ≤ Zs/Zsc ≤ 0.85 :fs/fsc = 0.3 (Zs/Zc)2 - 0.02 (Zs/Zsc) + 0.77

For 0.85 ≤ Zs/Zsc ≤ 1.4 :fs/fsc = 0.98 – 0.01 (Zs/Zsc)

For Zs/Zc ≥ 1.4 :fs/fsc = 0.95

For Base fb/fbc = (Zb/Zbc)1.2

Recommendations

To develop a computer code to predict load settlement based on derived load transfer curves

Instrumented load test on other geological formations

1 cycle tests – if piles instrumented

Geological description included in SI.

THANK YOU

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