Chapter 04 Capacity Measurements of Bored Cast In-Situ RC

Chapter 04

Capacity Measurements of Bored Cast In-Situ RC Piles Bearing on Rock and Estimation of Dynamic Soil Parameters

4.1 Introduction

In this chapter, application of stress wave theory, use of Case Pile Wave Analysis Program (CAPWAP), for studying of bearing capacity of rock socket bored cast insitu end bearing piles is described. Dynamic pile testing data of 28 number of end bearing bored piles considered in the analysis. Out of them, four piles were also static load tested and the load settlement curves predicted by CAPWAP were compared with the load settlement curve obtained from the static load test. Different analysis method including original, automatic, best mach, RSA, and radiation damping CAPWAP results are compared with static load test for different damping options. The importance of using CAPWAP restricke results when comparing capacities is discussed. The guidelines for selecting shaft radiation damping parameters used in this correlation studies are also presented. The following four case studies and other

Figure 4.1 Location of Figure 4.1 Location of selected sites cases were selected to reflect a variety of soil and pile conditions.

The damping factors and quakes along the pile shaft and at the pile toe are the most important dynamic soil parameters for capacity estimation by CAPWAP. In Sri Lanka a uniform soil layer along the pile shaft and the toe is not common and"frequently a layered soil profiles are very common. For these layered soil an average damping factors and quakes are estimated. Within the same soil type, variations of the values for these parameters are also discussed under different analysis type. The effect of the pile type, pile size, resistance distribution, restrike method for the soil parameters are also reviewed.

The objectives of the case study presented here include:

1. To investigate reliability of CAPWAP capacity predictions; 2. To determine a range for dynamic soil parameters met under local soil

condition; 3. To critically evaluate CAPWAP procedures and-results for future

improvement;

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4. To study CAPWAP's soil radiation damping model and to provide guidelines for its proper use;

5. To investigate relationship between the dynamic parameters (damping and quakes) with respect to soil types.

4.2 Correlation Considerations

A complete pile testing program was carried out at ten piling projects in Sri Lanka. Locations are shown in figure 4.1 Ground investigations was performed at each projects comprising following field and laboratory tests to determine designed soil parameters and classify the sub soils, (i) Standard Penetration Test (SPT) (ii) Cone Penetration Test (CPT) (iii) Sieve Analysis (iv) Consolidated undrain Triaxial Test (CU) (v) Unconsolidated Undrain Triaxial Test (UU) (vi) Consolidated Drain Test (CD) (vii) Unconfined Compressive Strength Test. The results of the soil test are tabulated under each case. The piles were checked first for integrity using pile integrity tester (PIT™) and based on PIT results, some piles were selected for load tests. When the results of static and dynamic load test done on same pile are compared, it should be recognized, however, that force or displacements of any static load test may contain errors. Further more, in many soils, pile capacity continually changes with time due to setup or relaxation, and thus many specifications require a wait period after installation before the static load test is performed. Since static and dynamic testing usually are done after different waiting periods, further differences in capacity should be expected, and differences increase as time between tests increases. Potential measurement errors in both static and dynamic tests, different failure definitions in ultimate capacity evaluation, and differences in time of testing after installation make exact agreement between static and dynamic test results is virtually impossible. In the present analyses Davission failure criterion are of the more conservative failure criterion, was used to obtain the ultimate carrying capacity from dynamic and static load tests.

After CAPWAP automatic matching was complete, the soil model was manually iteratively improved to obtain a best match with lower error differences with an assumed subsurface based on the site investigation results. This standard practice involves, as a minimum, the review of resistance distribution and other dynamic parameters. After the best match was obtained, the data was analyzed with the radiation damping soil model. In summery, the CAPWAP reanalyzed results include the automatic, best match, and radiation damping solutions.

4.3 Correlation of static load movement results

The pile top settlement predicted by CAPWAP from dynamic measurements are based on a dynamic event which only lasts 10 to 30ms. It is therefore necessary to consider the limitations of this test before attempting correlations. In general, settlement of piles include both primary and secondary components. For piles driven into coarse grained or overconsolidated materials, primary settlements are probably predominating. Fine grained soil often exhibit additional settlement under sustained loads which the dynamic load tests cannot predict. Additional consideration are therefore necessary, when pile test are performed in soils with consolidation or creep potential to avoid underpredictions of settlements.

Underpredictipns of load primarily occur when the dynamic test have been performed at the end of driving when the soil was remolded or when dynamic loads caused elevated pore water pressure [Thilakasiri, H.S., Abeysinghe, R.M., Tennakoon, B.L.,2003]. Over predictions are rarer, however, they may occur in a relaxing soil. Restrike test after an appropriate wait period therefore important. Furthermore, sufficient pile penetration per blow must occur during the test to "fail" the soil and cause a complete activation of all resistance forces. Since non activated resistance cannot be predicted by CAPWAP.

Poor result must also be expected if the measurements are inaccurate. This may happen, for example, if the pile material quality does not allow for an accurate calculation of forces from measured strains. Cracked concrete or yielded steel tops would preclude a linear material behavior. It is therefore important that the data is collected with accurately calibrated transducers. Under those circumstances, measurement errors can be detected by an experienced engineer such that immediate decisions or remedial action when needed can be taken.

Each selected pile was dynamically tested and CAPWAP analysis was performed. Maintain Static Load test were done on four dynamically tested piles. Comparison between measured and calculated data, as well as discussion of the results, can be used to show the reliability of the dynamic method and valid range for dynamic soil parameters. In order to see the influence of soil parameters and the other unknowns on the computed pile top variables a sensitivity CAPWAP analysis was performed for each case. In most cases, observed settlement per blow for rock socket end bearing piles was less than 2mm resulting very high blow count. The dynamic record for these piles and lager diameter piles were analyzed with radiation damping option in addition to standard CAPWAP analysis. Static load settlement curve was plotted and CAPWAP estimated load settlement behavior varied until that coincides with static load settlement curve.

4.4. The Data Analyses The measured dynamic measurements by PDA are reviewed and checked for quality and then one data record with good quality was selected for analyses. The rigorous computer software called CAPWAP was used to analyze the dynamic measurements in the data analyses part. All the analyses were done independently and the final outputs for each analysis are acceptable for final reports. A combination of linear viscous and Smith damping options for pile toe were applied for first five analyses. For the last analyses the radiation damping option for both pile shaft and toe was applied. The measured blow cont, wave propagation speed and elastic modules of the pile material kept constant through out the analysis. The resistant distribution to the pile shaft, toe and along the pile shaft is changed in each analysis.

4.5. Case Studies - Static and Dynamic Load Test Comparisons

4.5.1 Case 1: Bored Cast-In-Situ End Bearing Pile at Karapitiya - Galle The project is proposed to develop existing hospital complex for cancer word by the health ministry at Karapitiya in Galle district. After carrying out site investigation program, a pile foundation was recommended consisting of 800mm diameter bored piles by department of building. The piles were installed in a vertical orientation by using percussion method while stabilizing walls with Bentonite Slurry. Dynamic and

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static pile load tests were performed on an instrumented 21.7m long pile about three month after pile installation.

Table 4.1 Description of test pile at Karapitiya

Description Pile 1 Date of Installation 15 February 2002 Date of Testing 23 May 2002 Pile material Grade 25 Concrete Pile Type Bored cast insitu end bearing Pile Diameter (mm) 800 Cross sectional area (cm ) 5026 Wave Speed (m/s) 4100 Material Specific Weight (ton/m ) 2.45 Pile Length (m) 21.70 Length Below Gages (m) 21.50 Socketted Length (mm) 500 Soil at Toe Weathered rock Hammer Model Drop (F.F) Ram Weight (ton) 7.0 Approximate Stroke(mm) 1500

4.5.1.1 Results from the Soil Investigation during the site investigation phase, seven boreholes were advanced at the site with SPT done at regular intervals.Based on SPT values, the sub soil layers were divided into sevn layers. Those on seven layers shown in figure 4.2 The Lataritic fill, Lataritic soil, highly weathered rock and basement rock were the recognized main soil layers on this site. Comparatively high SPT values below 10m from ground level were reported. Considering the compressibility and elastic modules of the soil layers the allowable working pressure was determined. In figure 4.2 and table 4.2 the summary of the results and details of the sub soil investigations are shown. The water table was 1.65m below ground level.

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Thickness (m) Description

0-2.00 Lateritic fill, dark brown mottled with reddish brown, moist clayey fine to medium sand with gravel

2.00-3.00 Very loose, dark brown mottled with dark gray, moist slightly organic clayey fine to medium sand

3.00-4.10 Very loose, light gray, wet slightly clayely medium sand

4-10-5-25 Light yellowish white, slightly fine sandy clay of intermediate plasticity

5.25-19.32

Weathered rock (white, wet, high plastic clayely, fine to medium graned moderately decomposed) Quartzo feldspathic rock

19.32-21.35

Very dense white, wet, fine to very coarse sand and laterite nodules in gravel size.

21.00-25.00

Weathered rock, white, wet,fine to medium grained slightly weathered, quatzo feldspathic rock

SPT N Value Vs Depth

50 60

Q.

8

Figure 4.2 Depth versus subsoil profile and SPT N values

Table 4.2 Designed Soil Parameter Values Layer No Description Depth (m) SPT (N) Rail

(kPa) F u

(kPa) 1 Lateritic Fill 0-2 2 2 Lateritic Soil 2-5 2 3A Highly weathered rock,

N<20 5-7 <20 200 10

3B Highly weathered rock, 20<N<40

7-14 20-40 300 30

3C Highly weathered rock N>40

>14 >40 750 60

4 Basement rock 2000 150

qaii = Net allowable end bearing capacity f,, = Ultimate skin friction coefficient

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SPT N Value

10 20 30 40

4.5.1.2 Instrumentation of the pile

Figure 4.3 (a), (h) strain transducer and accelerometer attachment (c) hammer impact to the pile

4.5.1.3 Results of Wave Measurement and CAPWAP analysis

Stress wave measurements were carried out during restrike of the pile. The pile top force and velocity curves were obtained from measured strains and acceleration as shown figure 4.4. Static load settlement curves predicted by CAPWAP. resistance distributions along the pile shaft are plotted. Five analyses without radiation damping and one analyses with radiation damping option were done by varying dynamic soil parameters shown in table 4.3. During the test the final pile top settlement independently measured using a level.

Definitions for CAPWAP Soil Parameter

J C S : Case Damping Factor for Skin J C T : Case Damping Factor for Toe J S S : Smith Damping Factor for Skin (s/m) J S T Smith Damping Factor for Toe (s/m) Q S Shaft Quake (mm) Q T Toe Quake (mm) U N : Negative Skin Friction Unloading Limit TG Tae Gap (mm) C S Unloading Quake/Loading Quake for Shaft C T : Unloading Quake/Loading Quake for Toe PL: Soil Mass at Pile Toe

(.7

The pile was extended 2m from its cut off level i.e ground level with grade 40 concrete. The cross sectional area at the sensor location was 5026cm2. The pile was instrumented using two strain gauges and two accelerometers, to record dynamic measurements with pile driving analyzer. 1.5 times pile diameter below the pile top as shown 4.3(a) and (b). A 7 ton weight steel block was dropped on to the pile top using lour ropes driven fully arrangement of crawler crane shown in figure 4.3(c). Three plywood sheets 12mm thick were used as cushion material.

SK: _ Soil Support Dashpot in impedance unit MS: Weight of Soil Mass between skin resistance and skin soil support

dashpot in force unit BT: Soil Support dashpot at the pile bottom MT: Weight of soil mass between toe resistance and toe soil support

dashpot in force unit LS: Unloading Level for Skin LT: Unloading Level for Toe PI: Pile Damping Factor

Table 4.3 Dynamic Soil Parameters CAPWAP Analyses Mode Parameter 1 2 -> 4 5 Radiation

Damping JCS: 0.15 0.131 0.178 0.178 0.144 0.127 JCT: 0.131 0.248 0.312 0.174 0.174 0.324 JSS: 0.776 0.617 0.94 0.693 1.039 0.508 JST: 0.378 0.757 1.067 0.626 0.439 0.736 QS: 2 2.5 2.5 2.5 2.5 3.89 QT: 6.68 6.68 6.43 7.74 6.96 5.49 UN: 1 1 1 0.67 1 1 TG: 0 0 0 0 0 0.25 CS: 0.794 0.794 0.925 1 1 1 CT: 1 1 1 1 1 1 PL: 0 1.241 1.241 1.324 1.019 1.86 SK: 0 0 0 0 0 0.2 MS: 0 0 0 0 0 2.99 BT: 0 0 0 0 0 5 MT: 0 0 0 0 0 2.99 LS: 1 1 1 1 1 1 LT: 1 - 1 1 1 1 1 PI: 0.03 0.03 0.03 0.03 0.03 0.03 Skin Resistance (Ton) 99.5 109.3 104.4 132 71.2 128.4

Toe Resistance (Ton) 178.1 168.5 150.4 143 203.8 226.6

Total Resistance (ton) 277.6 277.8 254.8 275 275 355

Match Quality 3.94 3.39 3.01 2.8 2.81 2.77 Measured Blow Count (b/m) 571 571 571 571 571 571 Estimated Blow Count (b/m) 665 583 665 1323 1496 755

Match Quality: A quantification of the agreement between measured and computed

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iooQom — For. Msd - Vel. Msd

500. OC

60ns

4 L/C

-500.00

Figure 4.4 Measured force and velocity near pile top

The measured force and velocity is proportionally increased up to first peak as shown in Figure 4.4. Then due to upward wave reflections, the two curves get separated. Another peak shows 2L/C after first peak resulting compressive wave reflection at the pile toe. The measurement is done only for a period of 80ms since the dynamic behavior is vanished or not significant beyond this time. The direction of the pile particle movement is changed after wave reflection at pile top.

1006b6§ — Force Msd - F o r c e Cpt

-500.00

Figure 4.5 Measures and Computed force at the pile top

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The measured upwards waves and computed upward waves are compared by using a wave equation program CAPWAP which is described in literature. The comparison is done according to the procedure described in chapter 3 for CAPWAP analysis. In figure 4.5 the measure force and computed or complementary force is shown.

variation of dapming factors

»- JCS: -«-JCT: - *r - JSS:

-~-JST:

Figure 4.6 Varialions of Damping Factors

Six different analyses for same data set were performed and corresponding damping factors for different damping cases are extracted. Average damping factors for skin and a unique damping factor for pile toe was obtained by CAPWAP analysis. In this case it is shown that the Case damping factors (JCS, JCT) are relatively smaller than Smith's damping factors(JSS, JST). However, the variation of damping factors for different analysis is not significant. The Smith's damping factors varies in between 0.4s/m to 1.0 s/m in same soil type for the six analysis type (See figure 4.6) while Case damping factors are varies in between 0.15 to 0.3.5. The Case damping factor for skin is almost constant and not much sensitive to the pile resistance. The total resistance for pile shaft, toe and match quality were the independent variables for these analyses.

Variation of Quakes 10.0

8.0

6.0

4.0

2.0

0.0 analysis 1 analysis2 analysis3 analysis4 analysis5 analysis6

radiation

Figure 4. 7 Variations of Soil Quakes

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The soil quakes values for each analysis is shown in figure 4.7 The skin quake is around 2.5mm while the toe quake is around 7.5mm. For large blow counts smaller quakes are observed. If the pile settlement under the hammer blow is very high, the toe quakes also fairly high which indicates weak ground condition at the pile toe.

The resistance distribution along the pile shaft predicted by CAPWAP for different analyses show approximately same variation. In upper soil layer higher soil resistance is indicated than in middle soil layers. Again the resistance is increased with the depth near pile toe. The same variation is predicted for the radiation damping analyses option. The same ration of the resistance to pile shaft and toe is taken for different analyses. Higher settlement is predicted for first five analyses than the last analyses i.e. with radiation damping option.

Skin Resistance Vs Depth

Unit Resistance (Ton/m2)

0 2 4 6 8 10 0 -i • 1

25

Figure4.8 Skin resistance distribution for different analysis

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Estimated Load Vs Settlment

W 10 — . ^ S . . .

1 2 • : : ; '

0 100 200 300 400

Load (Ton)

analysis2 analysis3 analysis4 -*— analysis5 — a n a l y s i s 6 radiation » analysisl

Figure 4.9 Load Settlement Curves predicted by CAPWAP The appropriate curve from CAPAP analyses for load set should coincide with the load settlement curve measured under static loading. The corresponding dynamic soil parameter for that analyses can be treated as correct soil parameters. 4.5.1.4 Static load test

Maintain static pile load test was performed on the same pile with four dial gauges and a loading cell according to ASTM D 1143. A dead load was applied on pile top by a hydraulic jack. The load was increased by 55ton increments for each step. The averaged load settlements curves, measured at the pile top and at a different levels during the static load test are shown in figure 4.10. Figure 4.11 shows the comparison of the static load settlement curve and the load settlements curve five CAPWAP analyses.

Final Settlments

C/3

12 ' : • o m o L o o i r ) O u r > o i r ) O u D o m o

C M u D r > ~ O C N i r ) r - - 0 ( N i n r - O r \ | i n • " - T - T - T - C M C N C N C N C O n c O

Load (Ton)

« - Final Settlments

Figure 4.10 Measured pile top settlement under static load

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Estimated Load Vs Settlment

Figure 4.11 Pile Top Settlement under static load test and jive CAPWAP analyses

CAPWAP analysis results indicate that the mobilized pile resistance was 277 ton or less than that for first five analysis results. The PDA data was reanalyzed with radiation damping option and the estimated total resistance was 355 ton. For the first five analysis CAPWAP has underpredicted the total pile resistance and over predicted pile settlement. But when the radiation damping is activated the prediction becom very similar to the measured load settlement curve by static load test. Automatic or best mach always does not predict correct load settlement behavior. If pile diameter is large or observed pile top settlement under hammer blow is very small, the radiation damping should be activated in CAPWAP analysis. However, in non of these two testing procedure the pile has not reached its failure load, resulting that the Davission failure criterion can not be applied to estimate failure load. The initial settlement i.e.. elastic compression of the pile is well predicted by all the CAPWAP analyses.

4.5.2.1 Case Study-2 Bored Cast In-Situ End Bearing Pile at Trincomalee

This site is situated in Tincomalee in the northern part of the country about 360km away from the city of Colombo. Bored cast insitu piles of 800mm diameter had been installed by rotary drilling method for foundation of silos on basement rock through a quartizite layer. Prior to the actual piling program a test pile was installed with the same reinforcement with grade 30 concrete. Dynamic pile load test was carried out on the test pile 17 days after the pile installation. . And its subsequent CAPWAP analysis

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and static pile load test were carried out for the evaluation of pile capacity, six hammer blows of a 7 ton weight drop hammer, were applied on the pile top with 50mm thick plywood sheet layer increasing drop height from 500mm to 2500mm by a 40 ton capacity mobile crane. Two strain transducers and two accelerometers were attached to the pile surface lm below from pile top to record wave measurements.

Table 4.4 Description of test pile Description Pile NO P-09 Date of Installation 05 November 2000 Date of Testing 22 November 2002 Pile material Grade 30 concrete Pile Type Bored cast insitu end bearing pile Pile Diameter (mm) 800 Cross sectional area (cm 2) 5026 Wave Speed (m/s) 3750 Material Specific Weight (ton/m ) 2.4 Pile Length (m) 16.71 Length Below Gages (m) 16.40 Soil at Toe Basement Rock Hammer Model Drop Ram Weight (ton) 7.00 Approximate Stroke(mm) 2000

4.5.2.2 Site Conditions

The result of the soil investigation report is shown in figure 4.12. According to the bore logs, the depth of boreholes are varied from 0.5m to 18m and a quartzite layer of thickness 0.4m and 0.65m respectively was present at boreholes BH 10 and BH 11 at depths of 2.66m and 2.7I'm. Basement rock at BH 10 and BH 11 was reached at depths of 8.62m and 9.6m respectively, basement rock is charnokitic gneiss. The SPT values are generally greater than 50 in the overburden soil for many boreholes. The ground water table is at a depth of around 4.3m from the surface. The overburden consists of a very strong layer of completely decomposed rock with unweathered corestones of charnockitic gneiss within it. The uniaxial compressive strength of rock cores taken from basement rock has varied between 25.82 N/mm2 and 27.17N/mm2. with an average of 26.3N.mm2.

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Depth Description

0.00- Very dense sand/ 2.60 dense gravel

2.60.4.00 Highly weathered quartzite and charnockitic gneises

4.00- Highly 20.00 weathered

quartzite, basement rock

0

SPT N value Vs depth

SPT N Value

20 40 6C 0

£ 10 CL

Q

5 .

15

20

- • - B H 1 0 • B H 1 1 BH-04 , BH-05 ^ B H - 1 2 - ^ . - B H 14

Figure 4.12 sub soil profile

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800.00 tons

400.00

-OTQQ-

For. Msd Vel. Msd

N 84 ms

12 L/c

-400.00

Figure 4.13 measured force and velocity

The measured force and velocity for blow number 5 is shown in figure 4.13. The force and velocity plots were consistent and proportional for each blow. In the loading part i.e., up to first peak these two quantities was similar in magnitude except at the peak. Then the pile has rebounded and particle velocity has changed its direction.

800.00 tons

400.00

-OrOO-

Force Msd Force Cpt

84 ms

12 L/c

-400.00

Figure 4.14 Measured and computed force

In figure 4.14 the plot of the measured and computed force is shown. The two quantities are very similar in its magnitude indicating a satisfactory CAPWAP analysis. Six analyses, with one radiation damping analyses were performed on the PDA measurements. The soil parameters used for different analyses are shown in table 4.5.

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Table 4.5 CAPWAP numerical data CAPWAP Analysis Mode Parameter 1 2 3 4 5 Radiation

Damping JCS: 0.223 0.194 0.207 0.207 0.217 0.215 JCT: 0.977 0.99 0.855 0.855 0.82 1.052 JSS. 0.611 0.745 0.779 0.779 0.656 0.768 JST: 0.982 0.862 1.007 1.142 0.964 0.952 QS: 3.74 7.05 4.67 2.5 2.575 4.668 QT: 3.49 3.4 4.82 5.29 6.258 3.763 UN: 0.812 0.826 1 1 1 0.703 TG: 0.17 0.17 0.17 0.17 0.17 0.17 CS: 1 0.515 1 1 0.971 1 CT: 1 1 1 1 1 1 PL: 0 0 0 0. 0 0 SK: 0.75 0.8 0 0 0 0.75 MS: 2.77 2.774 0 0 2.77 2.77 BT: 5 5 0 0 0 5 MT: 2.77 2.774 0 0 2.77 2.77 LS: 1 1 1 1 1 1 LT: 1 1 1 1 1 1 PI: 0.02 0.02 0.02 0.02 0.02 0.02 Skin Resistance (Ton) 171.6 122.5 125.0 125.0 155.5 131.8

Toe Resistance (Ton) 486.1 450.0 399.5 325.2 346.6 505.9 Total Resistance (ton) 639.7 662.5 524.5 477.1 502.0 637.7

Match Quality 4.90 4.88 4.42 3.90 3.67 4.36 Measured Blow Count (b/m) 500 500 500 500 500 500 Estimated Blow Count (b/m) 150.4 2442 9999 22257 16870 3624

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Variation of Damping i i i

1.8 -

1.6

1.4

j I 1 . 2 -

f 0.8 03 Q

0.6

0.4 -

0.2

0

analysisl analysis2 analysis3 analysis4 analysis5 analysis6

Figure 4.15 Variation of damping factors Variat ion of Soil Quakes

2

1

0 analysisl analysis2 analysis3 analysis4 analysis5 analysis6

Figure 4.16 Variations of Soil Quakes

Depth VS Skin resistance

load (Ton/m2)

0 2 4 6 8 10 12

Figure 4.17 Skin resistance distributions

The resistance distribution along the pile shaft and axial pile load is shown in figure 4.17. The skin resistance in the middle portion of the pile is smaller while in the pile top and bottom portion is higher. Gradual increase in skin resistance distribution is observed from middle to the pile bottom.

Load Vs Settlement load (Ton)

0 200 400 600 800

12

Figure 4.18 Predicted pile top settlement by CAPWAP

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CAWAP predicted load-settlement curves for different analysis of the same blow is shown in figure 4.18. The pile bottom settlement can also be predicted by CAPWAP is plotted in the same figure. For same load, pile bottom settlement is lesser than that of pile top indicating stiff or rigid end bearing layer. The predicted maximum pile top settlement under 610 ton is 10mm.

Load VS Settlement

Load (kN)

700

9.00 - - - -

Figure 4.19 Measured pile top settlement under static load

Load Vs Settlement

load (Ton)

0 200 400 600 800

Figure 4.20 Pile Top Settlement under static and dynamic loads

A static maintain pile load test was performed lOdays after the dynamic pile load test and corresponding results are shown in figure 4.19 In this case also CAPWAP has overpredicted the settlement under same sustained load. The pile does not reached to

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its ultimate load by the two methods resulting no intersection of the Davission offset method.

4.5.3 Case III Pile Testing at Kalaniya Century Properties piling Project

The site is located in a reclaimed area on Colombo Kandy road at Kelaniya in Colombo district of western province. For a factory building 98 number of 500mm diameter bored rock socket end bearing piles had been installed by rotary drilling. Three full scale static pile load tests and two dynamic pile load test on two of the static load tested piles were carried out within 10 days.

Table 4.6 Description of the test pile Description P-23 P-13 Date of Installation 2 August 2002 4 August 2002 Date of Testing 11 September 2002 11 September 2002 Pile material Grade 25 concrete Grade 25 concrete Pile Type Bored end bearing pile Bored end bearing pile Pile Diameter (mm) 500 500 Cross sectional area (cm 2) 1963.5 1963.5 Wave Speed (mis) 3750 3750 Material Specific Weight 2.4 2.4 (ton/m 3) Pile Length (m) 18.68 19.5 Length Below Gages (m) 18.5 19.3 Soil at Toe Basement rock Basement rock Hammer Model Drop Drop Ram Weight (ton) 7.0 7.0 Approximate Stroke(mm) 500 500

4.5.3.1 Site Conditions

Sub soil investigation was done including seven borehole test up to the bed rock with carrying out Standard Penetration Test at 1.0/1.5m intervals through overburden. The average depth to the basement rock was 18m from ground level. The sub soil profile is shown in figure show in figure 4.21. The variation of SPT values with depth was generally uniform for each borehole. Depth to the ground water table wa"s 1.3m from existing ground level.

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0-0.8 CL/CS, Loose slightly plastic lateritic clay with sand

0.8-3.85 Pt, Very soft partially decomposed organic brown matter

3.85-9.10 CL, Very soft slightly to moderately plastic clay mixed with some sand

9.10-12.33

OL, Very soft to slightly to moderately plastic organic silty clay

12.33-15.26

CL/SC, Medium to stiff/ loose to medium dense slightly plastic sandy clay/ clayey sand

15.26-17.39

ML, Completely decomposed rock in the form of very stiff slightly clayey silt mixed with partially weathered mica and black iron minerals.

Above 17.50

Highly decomposed rock in the form of extremely dense silty and with partially decomposed mica

Varation of SPT Values with Depth

SPT N Values

0 20 40 60

6 - W ^

£ 10 a. <v Q

12

14

16

18

20

Figure 4.21 Sub Soil Profile

82

400.00 tons For. Msd

ms

\ /

-200.00

Figure 4.22 Measured force & velocity P-23

4 0 0 .00 tons

1/1 V \

Force Msd — — Force Cpt

2 0 0 .00 ll \

' \ -

o.oa 1

- J t \ 194 m s

34 L/c

-200 .00

Figure 4.23 Calculated and measured force P 23

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- 2 0 0 . 0 0

Figure 4.24 measured and Calculated force P 13

- 2 0 0 . 0 0

Figure 4.25 Measured velocity and force P-13

The measured force and veloci ty were consistent and proport ional for each record up to the first peak. The measured ve loc i ty plot for pi le P-13 shows tensile reflections before 2L /c . The pile rebound starts after 2 L / C i.e., pi le change movement direct ion. Then ve loc i ty and force come to zero posi t ion.

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Table 4.7 Dynamic Soil Parameters for pile P23 CAPWAP ' Parameter

Analyses Mode CAPWAP ' Parameter 1 2 3 4 5 Radiation

Damping JCS: 0.416 0.415 0.415 0.415 0.288 0.232 JCT: 0.373 0.248 0.204 0.204 0.487 0.308 JSS: 0.8 0.67 0.625 0.986 0.998 0.42 JST: 0.848 0.645 0.536 0.516 0.923 0.608 QS: 2.5 3.12 3.12 2.5 7 3.89 QT: 7.09 6.508 7.67 7.93 7.7 7.32 UN: 0.583 0.548 0.555 0.555 0.965 0.589 TG: 1.05 0.415 0 0 0.68 0 CS: 1 1 1 1 0.76 1 CT: 1 1 1 1 1 1 PL: 0.234 0.572 0.534 0.534 1.175 1.101 SK: 0 0 0 0 0 0 MS: 0 0 0 0 0 1.67 BT: 0 0 0 0 0 0 MT: 0 0 0 0 0 1.67 LS: 1 1 1 1 1 1 LT: 1 1 1 1 1 1 PI: 0.02 0.02 0.02 0.02 0.02 0.02 Skin Resistance (Ton) 95.6 114.8 122 77.4 97 101.7

Toe Resistance (Ton) 80.8 70.8 70 72.7 53 93.1

Total Resistance (ton) 176.4 184.7 192 150 •150 194.7

Match Quality 2.55 2.94 4.53 4.76 3.09 3.71 Measured Blow Count (b/m) 667 667 667 667 667 667

Estimated Blow Count (b/m) 591 584 652 621 563 569

Table 4.8 Dynamic Soil Parameters for pile PI 3 CAPWAP Parameter

Analyses Mode CAPWAP Parameter 1 2 4 5 Radiation

Damping JCS: 0.155 0.14 0.08 0.14 0.154 0.171 JCT: 0.383 0.369 . 0.466 0.371 0.357 0.342 JSS: 0.698 0.531 0.495 0.539 0.631 0.599 JST: 0.883 0.935 0.99 0.997 0.773 0.719 QS: 7.56 3.48 2.5 2.5 2.5 2.5 QT: 9.49 10.33 9.322 9.03 10.12 9.79 UN: 0.495 0.459 0.438 0.296 0.418 0.352 TG: 0.02 0 0 0 0 0 CS: 0.971 1 1 1 1 1 CT: 1 1 1 1 1 0.991 PL: 0.496 0.371 0.445 0.377 0 0.391 SK: 0 0 0 0 0 0

85

MS: 0 0 0 0 0 1.64 BT: 0 0 0 0 0 0 MT: 0 0 0 0 0 1.64 LS: 1 1 1 1 1 1 LT: 1 1 1 1 1 1 PI: 0.02 0.02 0.02 0.02 0.02 0.02 Skin Resistance (Ton) 42.1 50 30.6 49.3 46.3 54.2

Toe Resistance (Ton) 83.2 74.9 89.3 70.6 87.5 90.2

Total Resistance (ton) 124.4 129.4 119.9 119.6 134 144.4

Match Quality 3.80 4.41 4 .14 4.59 4 .20 3.97 Measured Blow Count (b/m)

->->-* j j j - » i j j j j j j -> -> j j j -»-»-> j j j 333

Estimated Blow Count (b/m) 501 306 340 319 443 500

1.2

c 1

03

| 0.8 o o cn c

0.6

| 0.4 03

Q 0.2

0

Variation of damping P23


Figure 4.27 Variation of damping factor for pile P-23

- » - J C S

J C T

J S S

J S T

86

Variation of Damping factors P-13

0 J ; : ;


JCS: m X T : JSS: JST:

Figure 4.28 Variation of damping factor for pile P-13

Variation of Quake P-23

10

2 1 0

0 1 2 3 4 5 6 7

Figure 4.29 Variation of soil quakes P-23

87

Variation of soil quakes P-13

12

10

(A

(TJ

o = 4 o c/>


Figure 4.30 Variation of soil quakes P-13

Skin Res is tance (Ton/m2)

2 3 4 5

0

2

4

6

8

£ 10

CL

&

12

14

16

18

20

-•— analysisl o analysis2

analysis3 analysis4 analysis6

Figure 4.31 Variation of Skin Friction P-23

88

Skin Resistance Vs Depth P-13

Resistance (Ton/m2)

0 1 2 3 1 0

2

4

6

1 8

i 1 0

Q 12

14

16

18

20

a analysis2 analysis3 analysis4 —*— analysis5 -•— analysis6

Figure 32 Variation of skin-resistance P-13

25 50

Load (Ton)

75 100 125 150 175 - a analysisl

aVialysis2 analysis3

*— analysis4 analysis6

Figure 33 Load Settlement Curves for different CAPWAP analysis P 23

89

static Load Set

L o a d (Ton)

0 25 50 75 100 125 150 175

16

» analysis2 analysis3 analysis4 - * - analysis5 -•— analysis6 radiation

Figure 34 Load Settlement Curves for different CAPWAP analysis P 13

Static Load

Load (Ton)

14

Figure 35 Load Settlement Curves from static load test P-23

90

static Load Set

Load (Ton) 0 25 50 75 100 125 150 175

30

35 -

Figure 36 Load Settlement Curves from static load test P-13

Load(Ton) 0 25 50 75 100 125 150 175 200

—•— Static Load » analysisl analysis2 '• analysis3 —*— analysis4 -•— analysis6

Figure 37 Load Settlement Curves for Static and different CAPWAP analysis P-23

91

static Load Set

Load (Ton) 0 25 50 75 100 125 150 175

- a analysis2 analysis3 analysis4 -*— analysis5 -*>— analysis6 radiation -•-+---•- static load set

Figure 38 Load Settlement Curves for Static and different CAPWAP analysis P-13

4.6 Case Studies -Dynamic Load Test Result 4.6.1 Case IV Bored Cast -In-Situ End Bearing Piles on Rock at 2000 plaza

Six bored cast in-situ piles diameters varying between 800mm to 1000mm were dynamically tested. The bore hole had been drilled using percussion method and the walls of the boreholes were supported with Bentonite slurry. Eight borehojes had been advanced up to basement rock with SPT done 1.5m intervals. The summery of subsoil profile is shown in figure 3.38 The pile was concreted with grade 30 concrete up to cutoff level and extended about 2m from its cutoff level with grade 40 concrete. Dynamic pile tests was performed about one month after the pile installation. The lengths and other physical properties of the piles are summarized in Table 4.8. The force and velocity records of figure 4.39(a). (b) was measured near the pile top. The subsoil profiles, CAPWAP predicted resistance distribution and measured dynamic data are given in figure 4.40(a) and in Table 4.9 while CAPWAP estimated load set curve is in figure 4.40(b).

92


0.00-1.85 SC/GC, Medium dense lateritic fill

1.85-3.00 OH, Extremely soft organic

3.00-4.50 CH/SC, Medium to stiff clay

4.50-7.95 SM/ML, SM/SC, medium dense, completely decomposed rock (residual soil)

7.97-14.30

SM/SC, Extremely dense, highly weathered rock

Above 14.30

Charnockitic Gneiss, Biotite Gneiss, Ganeti ferrous, . quartzo feldspathic gneiss

Depth Vs SPT N Values

N Values

20 40

Figure 4.38 Subsoil profile

Table 4.8 Description of test pile

Description Pile l/B-24 Pile 2/K-13 Pile 3/L-07 Pile 4/R-28 Pile 5/T-28 Date of Installation 10/01/2001 23/12/2000 07/01/2001 15/01/2001 5/01/2001 Date of Testing 28/02/2001 30/01/2001 12/02/2001 26/26/2001 19/02/2001 Pile material G30

Concrete G30 Concrete

G30 Concrete

G30 Concrete

G30 Concrete

Pile Type Bored pile Bored pile Bored pile Bored pile Bored pile Pile Diameter (mm) 800 800 1000 800 1000 Cross sectional area (cm 2)

5026 5026 7853 5026 8753

Wave Speed (m/s) 3800 3500 3550 3500 3500 Material Specific Weight (ton/m 3)

2.4 2.4 2.4 2.4 2.4

Pile Length (m) 13.3 9.1 8.4 15.3 14.4 Length Below 12.9 9.0 7.8 15.0 14.1

Gages (m) Soil at Toe Basement

rock Basement rock

Basement rock

Basement rock

Basement rock

Hammer Model Drop (F.F) Drop (F.F) Drop (F.F) Drop (F.F) Drop (F.F) Ram Weight (ton) 7 7 7 7 7 Approximate Stroke 1250 1000 1000 1850 1000

Table 4.9 Dynamic soil parameters Description Pile l/B-24 Pile 2/K-13 Pile 3/L-07 Pile 4/R-28 Pile 5/T-28 JCS 0.483 0.197 0.089 0.352 0.123 JCT 0.745 0.328 0.144 0.275 0.313 JSS 0.446 0.595 0.201 0.659 0.505 JST 0.569 0.377 0.292 0.419 0.398 QS: 2.357 3.03 3.17 0.94 2.5 QT: 3.992 9.25 5.76 9.05 6 UN: 0 0 0.821 0.425 0.21 TG: 0 0.01 2.94 0.28 0.44 CS: 1 1 1 0.949 1 CT: 1 0.9 1 0.943 0.9 PL: 0 0.246 1.849 0.165 2.136 SK: 0 0.06 0 0 0.61 MS: 0 2.58 3.36 2.62 3.28 BT: 0 4.52 0 0 4 MT: 0 2.58 3.36 2.62 3.28 LS: 0.98 1 1 1 1 LT: 0.99 0.9 1 1 0 / PI: 0.02 0.01 0.37 0.1 0.14 Skin Resistance (Ton)

475 144 305 232 165

Toe Resistance (Ton) 574 378 340 286 534 Total Resistance (ton) 1049 523 646 518 700 Match Quality 3.59 4.1 4.43 4.68 4.2 Measured Blow Count (b/m)

1000 667 500 667 1000

Estimated Blow Count (b/m)

847 506 666 760 980

1200 00 !u"i

A A 600 00 < \

14 / • \ ,, o fin ^ 1 \ - -—-

74 mj

13 L/c

•600 00 1 ' \ /

B-24,(a)

1200.00 ions

B-24, (b)

94

1200.00 Ions For. Msd

' V i — - Vel. Msd

600 00

H 1 ooo /

\ \ . - - 16 Uc

\ , '

•600.00

K-13,(a)

L-07,(a)

R-28,(a)


- Vel. Msd

800 00

A 0-00-

>

64 ms

" " 1 5 Uc

•800 00

1000.00 Ions For. Msd Vei. Msd

500.00 j: \

' • \ ,4 j

• •- — - - ooo- — /

64 ms

7 Uc

•500 00

16QOr00

ft -For Msd

Vel. Msd

800.061

t • J i : —^ ij/ K ^ . - - —

-600.00

1200 00 tons Force Mid

— Force Cpt

600 00 . I \

64 mi

16 L/c

•600 00

K-13,(b)

L-07,(b)

R-28,(b)

1600 00 tons

A Force Msd

-• - Force Cpt

800 00 • / \

j \ 43 00 J

j \ 43 00 J

64 ms

15 L/c

•800 00

1000.00 tons — Force Msd

- Force Cpt

500.00 / ' A \

1 4 / \

\ ,.r\ 64 ms

7 L/c

•500 00

I6M80 -Force Msd

II Force Cpt

600 po

j j 1 4 I i 5 0 i s

M O \ M\J^-~ _ 6 L/C

•800.00

T-28,(a) T-28, (b)

Figure 4.39 Force and velocity plots near pile top (a) Measured (b) Matched

60

tons/m 30

0 -

375

750

1125

1500

tons

_ Shaft Resistance

II Distribution

Pile Forces ' at Ru

B-24, (a)

Load (tons)

Displacement (mm; 12.00 '

B-24,(b)

Pile Top

— — Bottom Ru = 1049.8 Rs = 475.1 Rt) = 574.6 Dy = 12.3 Dmx= 12.5

ions tons ions mm mm

95

28.

2' !

200;

400 '

600

900

Shan Resistance Distribution

. d l l

K-13,(a)

12

8

125

250

375 ,

500 '— •

L-07,(a) 40

30

20

tons/m to

o -

200

400

eoo

aoo

Pile Forces at Ru

itn

tons

Shaft Resistance Distribution

Pile Forces at Ru


Pile Forces at Ru

Load (tons) 125.00 250.00 375.00

Displd£tfftent (mm;

16.00 ' — —

K-13,(b) Load (tons)

0.0CU- 125.00 250.00 375.00-. 000 •—

—500.00

Pile Too

4.00 ' "^^C^^s^ 8.00 !

Displ^c^rgientfmm).. . _. . . . _ .

Ru = Rs « Rb =

. I °1 = Omx =

469.6 53.8

415.8 116 13.4

Ions Ions tons

mm

16.00

L-07,(b)

0.00 200 00 0 00 — —

Load (tons) 400 00 600.00

• Pile Top Bottom

8 00

Displacement ( ™ J " " - -

16.00

Rs = Rb ' 0y = Omx -

518.5 Ions 232.5 tons 286 1 tons

13.6 mm 14.1 mm

R-28,(a)

10

tons/m 5

0-.

200

400 , 0 n s 600'

800 -

Shaft Resistance Distnbution

Pile Forces al Ru

R-28,(b) Load (tons)

0 00 200 00 400.00 600 00 0 00 v — •• -

Displacement (mm)

12.00 '

• Pile Top Bottom

Ru = Rs = Rb = Oy = Omx -

438.0 ions 104.9 tons 333.2 tons

9.0 mm 9.9 mm

T-28, (a) T-28,(b)

Figure 4 . 4 0 (a) Skin r e s i s t a n c e d i s t r i b u t i o n , (b) L o a d S e t t l e m e n t c u r v e s

4.6.2. Case V -Bored Cast In-Situ End bearing piles at Wattala

98 number bored cast-in-situ end bearing piles were installed at this site by percussion method. Seven piles were tested dynamically after about three week from piles installation for capacity evaluation. Ground investigation shows a thick peat layer followed by a lateric fill. The details of the pile and the soil profiles are shown in table 4.10 and figure 4.41. The piles were instrumented using strain gauges and accelerometers to record dynamic measurements figure 4.42 near pile top. The

96

velocity and force measurement, skin resistance distribution, CAPWAP predicted load settlement curve are shown in figure 4.42

Depth Description

0-4.95 Redish brown, yellow to rusty brown with white patches of sandy lateritic clay soft to firm, cohesive clay, coarse to medium angular sand

4.95-10.95

Yellow to rusty brown, pinkish to redish brown sandy lateritic clay, soft clay- cohesive slight plastic Sand- fine to coarse angular, lateritic modules found

10.95-13.00

Grayish black organic clay extremely cohesive very soft

13.00-15.00

Yellowish to grayish white with gray patches of silty clay Soft clay- plastic

15.00-16.00

Completely decomposed, very week gneissic rock

16.00-17.50 and above

Grained banded biotite gneiss rock

Depth Vs SPT N Values SPT N Values

0 20 40

BH 11 BH09 BH07 BH05


Table 4.10 Description of the test piles Description P-02 P-28 P-29D P-35 P-65 P.66 P-87 Date of Installation

27/03/01 09/03/01 04/04/01 14/03/01 27/04/01 29/04/01 23/04/01

Date of Testing

19/06/01 28/06/01 20/07/01 02/07/01 12/06/01 14/07/01 08/07/ul

Pile material G25 con G25 con G25 con G25 con G25 con G25 con G25 con Pile Type BP BP BP BP BP BP BP Pile Diameter (mm)

400 600 500 600 700 700 500

Cross sectional area (cm")

1256 2828 1964 2828 3849 3850 1964

Wave Speed (m/s)

3500 3500 4000 3500 4500 4000 4000

97

Material Specific Weight (ton/m 3)

G25 Concrete

G25 Concrete

G25 Concrete

G25 Concrete

G25 Concrete

G25 Concrete

G25 Concrete

Pile Length (m)

10.4 12.1 21.54 20.34 22.45 21.78 17.56

Length Below Gages (m)

10.2 11.9 21.36 20.11 22.25 21.53 17.38

Soil at Toe Rock Rock Rock Rock Rock Rock Rock Hammer Model

Drop (F.F)

Drop (F.F)

Drop (F.F)

Drop (F.F)

Drop (F.F)

Drop (F.F)

Drop (F.F)

Ram Weight (ton)

7.0 7.0 7.0 7.0 7.0 7.0 7.0

Approximate Stroke

400 1000 775 700 850 780 780

Table 4.11 Dynamic soil parameters Description P-02 P-28 P-29D P-35 P-65 P-66 P-87 JCS 0.255 0.144 0.6 0.144 0.354 0.484 0.569 JCT 0.383 0.281 0.13 0.827 0.388 0.126 0.065 JSS 0.591 0.888 0.757 0.351 0.973 1.312 0.893 JST 0.397 0.616 0.338 0.741 1.256 0.549 0.15 QS: 2.4 2 2.12 2 2.5 3.07 2.5 QT: 12.53 11.19 7.32 7.9 4.69 4 5 UN: 0.029 0.333 0.057 0.735 0.144 0.22 0.048 TG: 0.74 0.68 0.02 0 0.01 0.27 0 CS: 1 1 1 1 0.145 1 1 CT: 0.874 0.865 0.751 1 0.832 0.991 1 PL: 1.379 0 0.7 0 0.722 2.093 1.305 SK: 0 0 0 0 0 0 0 MS: 0 0 0 0 0 0 0 BT: 0 0 0 0 0 0 0 MT: 0 0 0 0 0 0 0 LS: 1 1 1 1 1 1 1 LT: 1 1 1 1 1 1 1 PI: 0.02 0.02 0.02 0.02 0.02 0.02 0.02 Skin Resistance (Ton) 53 40 155 101 122 142 124 Toe Resistance (Ton) 118 112 75 275 104 88 85 Total Resistance (ton) 171 152 230 377 226 230 210 Match Quality 3.57 3.29 2.48 4.3 3.8 4.6 3.96 Measured Blow Count (b/m) 333 333 500 500 500 500 500 Estimated Blow Count (b/m) 452 366 508 680 542 573 486

98

300,00ns — For. Msd

- Vel. Msd

150.00/ ''\

;14 1 — n 60ms —

O w 1 18Uc

•150.00

P-02,(a)

500.00 ions

250.00 / \

For. Msd — • Vel Msd

M / \ \

74 ms a e o /

\ —- , - ~ - .... .... •— 16 Uc

•250.00

P-28,(a)

400.00 ions For. Msd

A — - Vel. Msd

200.00 I ',1

,' ' '\ -a.oo-f \ ^—-——^-

150 m s , —

22 Uc

20000

P-29D, (a)

600.00 Ions

A

l\ For. Msd Vel. Msd

300.00

Ions

A

l\ ,./ A. 64 ms

-. 6 Uc

•300.00 |~Pile

P-35, (a)

400.00 tons For. Msd Vel. Msd

200.00 /

14 / 1

0 . 0 0 — - y

64 ms

•200.00

P-65,(a)

300.00ns — Force Msd

A - Force Cpt

150.00/ \

J ^ BOms —

18Uc

•150 00

P-02,(b)

P-28,(b)

P-29D, (b)

P-35,(b)

V

50000 tons

A Force Msd — • Force Cpt

25000 / \

\ \

0JO ' ^ . . ^ 74 ms

16 L/C

-250 00

400 00 ions

A

20000 1

j \ 150 ms^

22 L/C

•200 00

- Force Msd Force Cpt

64 rns

6 Uc

400.00 tons

f \ Force Msd — • Force Cpt

200.00 /

14 / 000-

64 ms

7 Uc

-200.00 •

P-65,(b)

99

800 00 ons For. Msd

— Vel. Msd

300.00 1 0 « O ~ '

194 ms

31 L/c

300 00

P-66,(a)

500.00 (ons For. Msd

A Vel. Msd

250.00 / ll

^ 184 ms

"'"36 Uc

•250.00

600.00 Ions

\ Force Msd

— - Force Cpl

300.00

194 ms

31 L/c

300.00

P-66,(b)

'-87, (a) P-87,(b)

Figure 4.42 (a) Measured velocity and force, (b) Matched force

500.00 ions Force Msd

A Force Cpl

250.00 I I

| \

_ 184 ms

36 L/c

•250.00

9

6

:ons/m 3 0 J

50

100

150

200

P-02,(a)

:ons/m 3 0 -

50

100

150

200

Ions

him

P-28,(a)

Shan Resistance Distribution

28

21

210

280

P-29D, (a)

Pile Forces at Ru


Pile Forces at Ru


Pile Forces al Ru

P-02,(b) Load (tons)

100.00 15000

DispllMftienl (mm)

• Pile Top Bollom

Ru = 152.6 ions Rs = 40.0 ions Rb = 112.6 Ions

«* Dy = 13 7 mm Dmx = 139 mm

P-28,(b)

P-29D, (b)

100

7 0 '

210

260

P-35,(a) 1 6 r 1 2 !

300

400

P-65,(a) 20

15

10

tons/m 5

o

70

140

S 210

280

P-66,(a) 20

15

10

tons/m 5

210

280

Snaft Resistance Distr ibution

Pile Forces at Ru

Shaft Resistance Distr ibution

Pile Forces at Ru

Shaft Resistance Distr ibution

Pile Forces al Ru

Shaft Resistance Distnbul ion

Pile Forces at Ru

Load (tons) 100.00 200.00 300 .00

Pile T o p

Displacement


7 0 0 0 140.00 210.00

Ru = Rs o Rb a Dy = D m x =

- Pile Top Bot tom

226.1 tons 122.3 Ions 103.8 tons

7.8 m m 8.0 m m

Displacement (mm)


70.00 140.00 210.00

3 ^ 0 0 ^

- Pile Top Bot tom

Ru = Rs = Rb = Oy = Dmx =

230.1 tons 141.8 tons

88.3 tons 7 0 m m 8.5 m m

Displacement (mm)


0.00 70.00 140.00 2 1 0 0 0

o.oo — - Pile Top Bot tom

Ru = Rs = R b = Dy = D m x =

210.0 tons 125.0 tons

85.0 ions 8.6 m m

13 7 m m

Displacement (mm)

P-87,(a) P-87,(b) Figure 4.43 (a) Resistance distribution, (b) load Settlement curve

101

4.6.3 Case VI Malatnbe Precast RC Driven Pile

Precast RC concrete piles are driven in to weathered rock stratum through a lateritic fill for a foundation of a bridge. High strain dynamic pile load test was performed on one of these pile for capacity evaluation 27 days after the pile installation. Four hammer impact were applied on to the pile top and corresponding settlement of the pile top were recorded with a EDM. A thin layer of plywood sheet was used as pile cushion materials. The dynamic data were analyzed and solutions for dynamic soil parameters were extracted. The length and the cross sectional area of the test pile was 7m and 1963cm2 respectively.

Depth description SFT N Values

0 10 20 30 40 50 n

0-2.00 Lateritic fill 1

2

3 «

;

2.00-6.00 Yellow to rusty brown, pinkish to redish brown sandy lateritic clay, soft clay- cohesive slight plastic Sand- fine to coarse angular, lateritic modules found

§; £ 4 Q .

8

5

6

\ — • — B H - 0 1

6.00< Weathered rock 7

8


Table 4.12 Dynamic soil parameters Description Pile 1 JCS: 0.138 JCT: 0.4 JSS: 0.783 JST: 0.956 QS: 2.13 QT: 7 UN: 0.932 TG: 0.63 CS: 0.584 CT: 0.8 PL: 1.165 SK: 0 MS: 0 BT: 0 MT: 0 LS: 1 LT: 1 PI: 0.02

•

102

Skin Resistance (Ton) 18 Toe Resistance (Ton) 42 Total Resistance (ton) 60 Match Quality 3.26 Measured Blow Count (b/m) 167 Estimated Blow Count (b/m) 183

800.0 kN

A A For, Msd

— • Ve l . Msd

400,0 f , \ I

. 0 -0 - ' .

'• \ yT+^X^^itH ms

. . . 94 U c

•400 0

60.00 tons - Force Msd

Force Cpt

. / \ 204 ms

P-01 (a) P-01 (b) F i g u r e 4 . 4 5 (a) M e a s u r e d v e l o c i t y a n d f o r c e , (b) M e a s u r e d a n d m a t c h e d f o r c e .

45

30

0 •

150

300

450

600

Shaft Resistance Distr ibut ion

Pile Forces at Ru

Load (kN) 150.0 300.0 450.0

P-01 . P-01 F i g u r e 4 . 4 6 (a) S o i l r e s i s t a n c e d i s t r i b u t i o n (b) p i l e t o p / b o t t o m s e t t l e m e n t

- Pile T o p Bot tom

Ru = Rs = Rb = Oy = D m x =

588 3 kN 174.3 kN 4 1 4 0 kN

8.7 m m 8.7 m m

4.6.4 Case Study VII Bored Cast insitu End Bearing Rock Socket Pile at Kirulapone Pile dynamic test and stress measurements on an end bearing bored pile was carried out at Kirulapone in the city of Colombo. 800mm diameter bored piles have been installed for a diaphragm wall and supporting a superstructure of a six stoned building on basement rock. The test pile was cut off 2m from its top level and built up 1.5m in the same section with 40 grade concrete. The pile was instrumented with strain transducers and two accelerometers near the pile top. Six hammer impacts were applied on to the pile top with 7.5 drop weight using a 45 ton mobile crane. The collected dynamic data were studied using CAPWAP analysis and subsequent output from CAPWAP are shown in following figures.

T a b l e 4 . 1 3 D e s c r i p t i o n of the t e s t p i l e Description P-09 Date of Installation 02/02/2003 Date of Testing 12/03/2003 Pile material Grade 30 Concrete Pile Type Bored pile Pile Diameter (mm) 800

103

Cross sectional area (cm 2) 5026 Wave Speed (m/s) 3900 Material Specific Weight (ton/m j) 2.4 Pile Length (m) 9.3 Length Below Gages (m) 9.1 Soil at Toe Basement rock Hammer Model Drop (F,F) Ram Weight (ton) 7.5 ton Approximate Stroke 1000

Depth Description

0-2.5 Loose clayey silt with traces of sand with occasional gravel

2.5-4.0 Loose reddish clayey silt with pockets of angular quatizitic gravel

4.0-8.79 Medium dense to dense pink to brown silt with traces of sand

8.79-11.00

Medium dense silt with traces of sand and clay

11.00-12.78

Medium dense silt with traces of sand and clay

12.78-13.60

Medium dense pale brown sandy silt

13.60-14.78

Dense to very dense grayish silt with traces of sand (completely weathered rock)

S P T N Values

20 40 60

£ 8 Q .

& 10

12

14

16

« - BH-01

Figure 4.4/ Subsoil profile

Table 4.14 Dynamic soil parameters Description Pile 09 JCS: 0.252 JCT: 0.114 JSS: 0.588 JST: 0.112 QS: 2.65 QT: 3.24 UN: 0.023 TG: 0.59 CS: 0.521 CT: 0.966 PL: 0 SK: 0

104

MS: 0 BT: 0 MT: 0 LS: 1 LT: 1 PI: 0.02 Skin Resistance (Ton) 265 Toe Resistance (Ton) 630 Total Resistance (ton) 895 Match Quality 3.26 Measured Blow Count (b/m) 1000 Estimated Blow Count (b/m) 1253

1200.00 tons

A For Msd

— Vel. Msd

/ \ 600.00 / \

W f l ' " \ 54 ms

„ • - ' " 1 2 L/C

•600.00

1200.00 tons Force Msd Force Cpl

60000 j \

i \ _ 14 / "

\ 54 ms

9JXt-~ -J 12 L/c

-600.00

P-09,(a) P-09,(b)

F i g u r e 4 . 4 8 (a) m e a s u r e d f o r c e a n d v e l o c i t y , (b) m e a s u r e d a n d m a t c h e d f o r c e

80

60 Shaft Resistance

40 . " V OiSlriQution

20 l lons/m 1

0 Jl- jT 225 Pile Forces

450 at Ru

, 675 tons 900

Load (tons) 225.00 450.00 675.00

- Pile Top Boilom

Ru = Rs = Rb = Dy = Dmx -

895 8 ions 265 4 ions 630.4 ions

7.2 mm 8 3 mm

Displacement (mm)

P-09 P-09 F i g u r e 4 . 4 9 (a) s o i l r e s i s t a n c e d i s t r i b u t i o n (b) p i l e t o p / b o t t o m s e t t l e m e n t

105

4.6.5 Case Study VII Bored Cast insitu Rock Socket End Bearing pile at Rajagiriya

The test pile was installed at Rajagiriya in Colombo district for a foundation of a six storied office building. The dynamic pile load test was carried on extended pile with strain transducers and accelerometer attached to the pile. The measured force and velocity measurement were used for CAPWAP analysis. The results of the from stress wave measurement from the first blow of restricke are shown.

Depth Description S P T N V a l u e s

0 m 20 30 40 50 0-3 Fine to very coarse o

20 30 40 50

grained sandy lateritic clay 2 + - B H 0 4

i !

3-5.45 Very soft, wet, dark brownish peaty organic clay

4 - 4- •

+ - B H 0 4

i ! 5.45-6.45 Firm wet gray slightly

fine to coarse grained sandy clay

6

8

?

£ 10 -Q- < LU Q

12

14

i ~~~ 5=* ;—-

6.45-7.65 Very stiff, lateritic clay with some partially weathered lateritic nodules

6

8

?

£ 10 -Q- < LU Q

12

14

—

7.65-9 Fine to coarse grained sandy clay

6

8

?

£ 10 -Q- < LU Q

12

14 9-13.65 Fine to very coarse grained sand . 16

13.65-15.1

Slightly clayely fone to very coarse grained sand

18

20

- - •- - ;

15.1-17.28

Completely weathered rock

18

20

Figure 4.50 Soil profile

Table 4.15 Description of the test pile Description P-06 Date of Installation 4/01/2003 Date of Testing 11/02/2003 Pile material Grade 30 Concrete Pile Type Bored pile Pile Diameter (mm) 600 Cross sectional area (cm 2) 4900 Wave Speed (m/s) 3800 Material Specific Weight (ton/m J) 2.4 Pile Length (m) 17.42 Length Below Gages (m) 17.29 Soil at Toe Basement rock

106

Hammer Model Drop (F,F) Ram Weight (ton) 7.5 Approximate Stroke 1000

Table 4.16 Dynamic soil parameters

Description PI-06 JCS. 0.161 JCT: 0.182 JSS: 1.276 JST: 0.416 QS: 2.5 QT: 10.7 UN: 1 TG: 0.16 CS: 0.125 CT: 1 PL: 0.167 SK: 0 MS: 0 BT: 0 MT: 0 LS: 1 LT: 1 PI: 0.02 Skin Resistance (Ton) 58 Toe Resistance (Ton) 203 Total Resistance (ton) 261 Match Quality 4.65 Measured Blow Count (b/m) 667 Estimated Blow Count (b/m) 980

P-06,(a) P-06,(b)

Figure 4.51 (a) Measured force and velocity, (b) Matched force

107

ions/m 3|

225

300

Shaft Resistance j Distribution

• 1

j riltkl !

Pile Forces i at Ru

P-06,(a)

Load (tons) 75.00 150.00 225.00

Displacement

P-06,(b) Figure 4.52 (a) Soil resistance distribution, (b) Pile top/bottom settlement

4.6.6 Case Study IX Bored Cast Insitu Rock Socket End Bearing Piles at Wattala

Three dynamic data sets were collected on three bored piles constructed for foundation of a factory building. The piles were built up lm from its cut off level and instrumented with strain gauges and accelerometers to collect force and velocity traces with time. The test pile details, information of the subsoil and results of dynamic analysis are shown.

Depth Description Depth Vs SPT N Values

0-1.36 CL, Lateritic fill 0

1.36- Pt, Very soft moderately plastic 0

4.10 organic clay and decomposed organic mater 5

4.10- SP, Very loose fine to medium J h\ 6.5 grained sand

6.5-9.5 Medium stiff, very fine sand — 10 ' £ V

mixed with decomposed JZ I \ \ organic matter Q.

9.5- Stiff/ medium dense very fine to Q 15 I „ ~-~* "~ ^ .

12.5 medium grained sand

12.5-13.86

Dense fine to coarse sand 20

13.86- Hard to stiff very fine sand 16.76 mixed with organic clay 25

16.76- Dense fine to coarse sand 0 20 40 60

18.50 SPT NVLUES

18.5-21.92

Dense to very dense, fine to coarse sand BH-01 - * — BH02 —A— BH03


Table 4.17 Description of the test pile Description P-01 P-17 P-37 Date of Installation 09/01/2003 28/12/2002 12/01/2003

108

Date of Testing 26/02/2003 26/02/2003 26/02/2003 Pile material G25 Concrete G25 Concrete G25 Concrete Pile Type Bored pile Bored pile Bored pile Pile Diameter (mm) 500 500 600 Cross sectional area (cm 2) 1964 1964 2850 Wave Speed (m/s) 4350 3750 3850 Material Specific Weight (ton/m 3)

2.4 2.4 2.4

Pile Length (m) 22.8 18.68 16.9 Length Below Gages (m) 22.6 18.4 16.7 Soil at Toe Rock Rock Rock Hammer Model Drop (F,F) Drop (F,F) Drop (F,F) Ram Weight (ton) 7.5 7.5 7.5 Approximate Stroke 1000 400 500

Table 4.18 Dynamic soil parameters Description P-01 P-17 P-37 JCS: 0.188 0.408 0.407 JCT: 0.613 0.256 0.531 JSS: 0.605 0.894 1.072 JST. 1.21 0.56 1.265 QS: 2.5 2.92 2.5 QT: 7.98 1.6 5.48 UN: 0.283 0.758 1 TG: 0 0 0 CS: 1 1 1 CT. 1 0.05 0.75 PL: 0.224 1.774 4.064 SK: 0 0 0.6 MS: 0 1.69 2.02 BT: 0 0 5.06 MT: 0 1.69 2.02 LS: 1 1 1 LT: 1 1 1 PI: 0.02 0.02 0.02 Skin Resistance (Ton) 66 83 104 Toe Resistance (Ton) 108 83 114 Total Resistance (ton) 174 167 218 Match Quality 3.45 4.78 4.52 Measured Blow Count (b/m) 667 500 667 Estimated Blow Count (b/m) 680 490 786

109

400.00 Ions For. Msd

— • Vel. Msd

200.00 .

' \ ^- 194 ms

Vi / ^ \ _ 3 Uc ^ •* 2

.200 00

P-01,(a)

P-17,(a)

400.00 tons

' 1 \


— - Vel. Msd

1 \ I O O . O O j A

o.oa-J -204 ms

o.oa-J

/

" " ^ ^ 6 Uc

100 00

- For. Msd Vel. Msd

184 ms

36 L/c

400.00 tons Force Msd

I — - Force Cpt

200.00 I \

194 m

200.00

P-01,(b)

P-17,(b) 400.0 tons 0

200.0 0

P-39,(a) P-39,(b)

Figure 4.54 (a) Measured force and velocity, (b) Matched force

200.0 tons 0

A Force Msd Force Cpt

1000 1 \ 0 !

204 ms 0 . 0 0 — ' — 7 — —

" \ 36 Uc

• 100.00

• Force Msd Force Cpi

184 ms

36 Uc

tons/m 2 0 - —

50

100

Itons 1 5 0

200

P-01,(a)

P-17,(a)

Shaft Resistance' Distribution

Pile Forces at Ru

L o a d ( tons) 0.00 50.00 100.00 150.00 200.00

- Pile Top Bottom

Ru = Rs = Rb = Dy = Omx =

174 3 tons 66.3 tons

108 0 tons 11 6 mm 11 9 mm

12.00 D isp lacement ( m m )

P-01,(a) 16

12 Shaft Resistance

e Distribution

t o n s / m 4 I

o - -50 Pile Forces

at Ru 100 /

l o n s 150 / 2 0 0 - • ' •

0 0 0 L o a d ( tons)

50.00 100.00 150.00 200 00 Pile Top Bottom

4.00' -•

Ru = Rs = Rb = Dy = Dmx =

167 9 63.9 84.0

6.5 7 9

tons tons lons mm mm

D isp lacement

( m m ) 8.00 ^ -

P-17, (b)

110

ton s

16

12

8

m 4j

Or-

7oj

140[

210

2 8 0 -


Pile Forces at Ru

Load (tons) 7000 14000 21000

i_ 6 00 Displacement (mm)

P-39,(a) P-39,(b) Figure 4.55 (a) Soil resistance distribution (b) Pile top/bottom settlement

4.6.7 Case study X Bored Cast insitu Rock Socket End Bearing pile at Narahenpita

This site is situated at Narahenpita in Colombo district adjacent to the Baseline road. Four dynamic tests were carried out to check the structural integrity and the bearing capacity of end bearing bored piles which constructed for the foundation of Colombo district secretariat building. The test piles were installed two month before the dynamic load tests. The measured dynamic records which analyzed using CAPWAP and the results are shown in following figures.

Depth Description

0-3 Loose sand

3-7 Medium dense sand with clay and organic impurities

7-13 Peat /Peaty clay

13-21 Medium dense sand

Above 21

Basement Rock

10

£ 15 Q. <D

D

20

25

30

SPT N Values

20 40 60

BH01 BH 04

- « - BH 02 - * - BH05

- » r - B H 0 3

BH 06

Figure 4.56 Subsoil Profile

111

Table 4.19 Description of the test pile Description Pl-16 Pl-31 PI-28 P2-15 Date of Installation 15/12/2002 03/12/2002 21/12/2002 07/01/2003 Date of Testing 05/03/2003 05/03/2003 05/03/2003 05/03/2003 Pile material G30 Con G30 Con G30 Con G30 Con Pile Type Bored Pile Bored Pile Bored Pile Bored Pile Pile Diameter (mm) 500 500 500 600 Cross sectional area (cm 2)

1936 1936 2500 3600

Wave Speed (m/s) 4000 3800 3750 3685 Material Specific Weight (ton/m 3)

2.4 2.4 2.4 2.4

Pile Length (m) 24.78 23.75 24.21 23.13 Length Below Gages (m)

24.28 23.50 24.00 22.93

Soil at Toe Rock Rock Rock Rock Hammer Model Drop (F,F) Drop (F,F) Drop (F,F) Drop (F,F) Ram Weight (ton) 7.5 7.5 7.5 7.5 Approximate Stroke 1200 700 800 500

Table 4.20 Dynamic soil parameters Description Pl-16 Pl-31 Pl-28 P2-15 JCS: 0.427 0.435 0.363 0.144 JCT: 0.608 1.006 0.335 0.415 JSS: 0.742 0.57 0.56 0.282 JST. 1.113 1.302 0.9 1.298 QS: 3.02 3.72 2.5 1.58 QT: 3.62 4.94 2.61 3.27 UN: 0.185 0.177 0.037 0.212 TG: 0 0 0 0 CS: 1 1 1 0.943 CT: 0.985 0.444 1 0.449 PL: 0.781 0.008 0 1.3 SK: 0 0 0 0 MS: 0 0 0 0 BT: 0 0 0 0 MT: 0 0 0 0 LS: 1 1 1 1 LT: 1 1 1 1 PI: 0.02 0.02 0.02 0.02 Skin Resistance (Ton) 111 142 . 151 169 Toe Resistance (Ton) 105 143 87 105 Total Resistance (ton) 216 285 238 274 Match Quality 4.13 3.29 4.76 3.53 Measured Blow Count (b/m) 500 667 667 500 Estimated Blow Count (b/m) 387 702 650 687

112

300.00 tons For. Msd Vel. Msd

150.00 /

...'•/ \ \

84 ms

\ \

/

— ~ y

6 L/c

-ISO 00

Pl-16,(a)

300.00 Ions

f\ Force Msd Force Cpl

150.00 / / /

\ \

• - 0.00 , 4 / 64 ms

6 Uc

•150 00

Pl-16,(b) 200.00

100.00

tons For. Msd

— Vel. Msd

0 00 14/ 104 ms

\ / 12 Uc

•100.00

200.00 tons — Force Msd

Force Cpt

100.00 .' (

14 0 .00 - •

104 ms

12 L/C

•100.00

PI-31,(a) Pl-31,(b)

300.00 tons

h 150.00 ! \

I i

For Msd vel Msd

300.00 tons

150.00 '

Force Rovte Cpl

u o oo. J ^ y V _ j ' -

/,2Q4 ms 14 0.0 .-0

204 ms

28 Uc

14 0.0 .-0 2 3 L/C

•150.00 •150 00

Pl-28,(a) Pl-28,(b)


— - vel Msd

300.00 ton s Force Msd

Force Cpt

150 00

I A

150.00 : •

\ .. y<^2Q4 ms 14 204 ms

0r0r;—- >( —7 v ... 29 Uc 0.00

25 L'c

150.00 •150.00

P2-15,(a) P2-15,(b)

Figure 57 (a) Measured force and velocity (b) Matched force

113

6i tons/m 3 }

d'r 70!

140,

210J

2 8 0 ! -

JJ

Ions

Pl-16,(a) 20 -

15 '

10,

lons/m 5

0 —

75

150

225

300

tons

PI -31, (a)

Pl-28,(a)

si!Ptlii

150

225

300

P2-15,(a)

Shaft Resistance (Distribution

Pile Forces : at Ru


Pile Farces at Ru

Shaft Resistance Dislnbution

Pile Forces at Ru

L o a d ( tons) 70.00 140.00 210.00

9.00, D i s p l a c e m e n t ( m m )

Pl-16,(b) L o a d ( tons)

0^£ |§ -—. 50.00 100.00 150.00

2 00'

4 00

200.00 L o a d ( tons)

0^£ |§ -—. 50.00 100.00 150.00

2 00'

4 00


Pile Top Bottom

286,0 142.2 143.8

6.1 6.1

tons tons tons mm mm

D i s p l a c e m e n t ( m m )

8.00

Pl-31,(b) 28 - . ._ .

21 Shaft Resistance t

14 Distnbulion

tons/m 7

0 - -

70 Pile Forces

140 / at Ru

t 0 n S 210

280

L o a d ( tons) 70 00 140 00 210.00 280.00

- Pile Top Bottom

D isp lacement ( m m )

12.00 - —


238.7 tons 151.7 tons 87.0 tons

8 4 mm 9.1 mm

Pl-28,(b) L o a d ( tons)

[""""o.-oo. 70 00 140 00 210.00 = o c ~ " . ~ t ~ L . ^ - • - -

280.00 Pile Top Bottom

4 00

Ru = Rs = Rb = Dy = Dmx -

275.0 169 1 105 8

4 2 4 2

tons tons tons mm

Displale'Sent ( m m )

8.00 —

P2-15,(b)

Figure 4.58 (a) Soil resistance distribution (b) Pile top/bottom settlement

114

Documents

Chapter 04 Capacity Measurements of Bored Cast In-Situ RC