scholarly journals Influence of a permanent liner on the skin friction of large-diameter bored piles in Hong Kong granitic saprolites

2003 ◽  
Vol 40 (4) ◽  
pp. 793-805 ◽  
Author(s):  
S -C.R Lo ◽  
K S Li
Keyword(s):  
Numerical Simulation ◽  
Hong Kong ◽  
Skin Friction ◽  
Large Diameter ◽  
Full Length ◽  
Load Test ◽  
Test Results ◽  
Local Method ◽  
Bored Pile ◽  
Bored Piles

The skin friction of large-diameter bored piles in Hong Kong granitic saprolite manifested high variability. The influence of one construction detail, a full-length permanent liner, is studied by examining full-scale load test results and by numerical simulation of this construction detail. It is concluded that the use of a full-length liner will give very low skin friction because the local method of constructing a large-diameter bored pile with a full-length permanent liner leads to a significant reduction in radial stress acting on the pile–soil interface.Key words: construction, pile, stress, skin friction, numerical simulation.

A Destructive Field Study on the Behavior of Pile under Ten

2010 ◽  
Vol 163-167 ◽  
pp. 4524-4528
Author(s):  
Shi Min Zhang ◽  
Gang Wei
Keyword(s):  
Skin Friction ◽  
Load Test ◽  
Silty Sand ◽  
Silty Clay ◽  
Test Results ◽  
Bored Pile ◽  
Tip Resistance ◽  
Stress States ◽  
Sand And Gravel ◽  
Different Soils

This paper involves a destructive full-scale load test on long bored pile instrumented with strain gauges along the shaft. The load-displacement response, the distribution of axial force, and the thresholds of displacement for fully mobilizing the skin resistances in different soils in tension case were discussed in this paper. The field test results show that the measured tip resistance in the pile under tension is near zero during the whole loading, and the softening is accompanied with a reduction in skin friction when the skin friction is fully developed. It also can be investigated that the threshold of displacement for fully mobilizing skin friction is different even if in the same soil type due to different soil stress states. Generally speaking, the thresholds of relative pile-soil displacement for fully mobilizing skin frictions in the sandy silt, silty sand mixed silt, silty clay, silty clay mixed sand and gravel are about 4 mm, 11 mm, 7 mm, 6 mm, and 5.5 mm, respectively.

scholarly journals Accuracy and precision of the CSLT measurement system: An experiment to defect diagnoses in bored piles

2021 ◽  
Vol 28 (4) ◽  
pp. 176-185
Author(s):  
Zezhong Wang ◽  
Eric Tak Cho Ho ◽  
Inez Maria Zwetsloot
Keyword(s):  
Hong Kong ◽  
Measurement System ◽  
Measurement Accuracy ◽  
Large Diameter ◽  
Housing Projects ◽  
Bored Pile ◽  
Accuracy And Precision ◽  
Bored Piles ◽  
Pile Type ◽  
Sonic Logging

A new measurement system called Crosshole Sonic Logging Tomography (CSLT) provides information on the size, shape, and orientation of defects in a bored pile. The CSLT measurement system has not (yet) been accredited in Hong Kong for foundation testing. Bored piles in Hong Kong are generally wide and deep. Existing measurement accuracy studies do not consider this large type of bored piles. The objective of this research is to quantify the measurement accuracy and precision of the CSLT method for large diameter bored piles (the most common pile type for public housing projects in Hong Kong). A test pile was constructed with known defects and perform experiments with a CSLT measurement system to quantify its accuracy and precision. CSLT is found to be accurate in detecting shape, size, and location of large defects but small defects close to the tube are difficult to detect. Generally speaking, CSLT has satisfactory accuracy and precision for practical use. The use of CSLT can be considered as a feasible method in defect diagnosis of bore piles in Hong Kong.

scholarly journals Potential and prospects of photocatalytic disinfection: using sustainable solarenergy- driven photocatalysts

2021 ◽  
Vol 28 (4) ◽  
pp. 165-175
Author(s):  
Juhua He ◽  
Kenny W K Hui ◽  
Irene M C Lo
Keyword(s):  
Hong Kong ◽  
Measurement System ◽  
Measurement Accuracy ◽  
Large Diameter ◽  
Housing Projects ◽  
Bored Pile ◽  
Accuracy And Precision ◽  
Bored Piles ◽  
Pile Type ◽  
Sonic Logging

A new measurement system called Crosshole Sonic Logging Tomography (CSLT) provides information on the size, shape, and orientation of defects in a bored pile. The CSLT measurement system has not (yet) been accredited in Hong Kong for foundation testing. Bored piles in Hong Kong are generally wide and deep. Existing measurement accuracy studies do not consider this large type of bored piles. The objective of this research is to quantify the measurement accuracy and precision of the CSLT method for large diameter bored piles (the most common pile type for public housing projects in Hong Kong). A test pile was constructed with known defects and perform experiments with a CSLT measurement system to quantify its accuracy and precision. CSLT is found to be accurate in detecting shape, size, and location of large defects but small defects close to the tube are difficult to detect. Generally speaking, CSLT has satisfactory accuracy and precision for practical use. The use of CSLT can be considered as a feasible method in defect diagnosis of bore piles in Hong Kong.

Numerical Simulation of Bored Pile-Soil Interface Shear Performance

2013 ◽  
Vol 438-439 ◽  
pp. 1427-1432
Author(s):  
Qian Xu Liao ◽  
Jin Cao ◽  
Jun Wei Tang
Keyword(s):  
Numerical Simulation ◽  
Clayey Soil ◽  
Frictional Resistance ◽  
Measured Data ◽  
Interface Shear ◽  
Bored Pile ◽  
Model Pile ◽  
Shear Performance ◽  
Bored Piles ◽  
Soil Interface

This paper derives a numerical simulation of direct shearing test and model pile test based on the measured data of bored piles. Characteristics of the interface between bored pile and soil around it are analyzed. Laws of the magnitude and the distribution range of point resistance and frictional resistance of the bored piles in granular and clayey soil are obtained and the mechanism on them is explained.

Live-Load Test Results of Missouri’s First High-Performance Concrete Superstructure Bridge

2003 ◽  
Vol 1845 (1) ◽  
pp. 96-103 ◽  
Author(s):  
Yumin Yang ◽  
John J. Myers
Keyword(s):  
Load Distribution ◽  
High Performance ◽  
High Performance Concrete ◽  
Large Diameter ◽  
Load Test ◽  
Strain Gauges ◽  
Live Load ◽  
Test Results ◽  
Live Load Distribution ◽  
Live Load Test

For its significant economical savings and greater design flexibility, high-performance concrete (HPC) is becoming more widely used in highway bridge structures. High-performance bridges with HPC and large-diameter prestressed strands are becoming attractive to designers. Bridge A6130 is the first fully HPC superstructure bridge in Missouri. The bridge has HPC cast-in-place deck and high-strength concrete girders reinforced with 15.2-mm (0.6-in.) diameter strands. The bridge was instrumented with embedded strain gauges and thermocouples to monitor the early-age and later-age behavior of the structures from construction through service. To investigate the overall behavior of the bridge under live load, a static live-load test was developed and carried out. During the live-load test, 64 embedded vibrating wire strain gauges and 14 embedded electrical-resistance strain gauges were used to acquire the changing strain rate in the bridge caused by the varying live-load conditions. Girder deflections and rotations were also recorded with external sensors and a data acquisition system. Based on the test results, the load distribution to the girders was studied. The AASHTO specifications live-load distribution factor recommended for design was compared with the measured value and found to be overly conservative. The AASHTO load and resistance factor design live-load distribution factors recommended for design were found to be comparable to measured values. Two finite element models were developed with ANSYS and compared with measured values to investigate the continuity level of the Missouri Department of Transportation interior bent detail.

Testing Study on Bearing Behavior of Belled Large-Diameter PHC Pipe Pile by NAKS (Nakabori Kakutei System) Construction Method

2013 ◽  
Vol 353-356 ◽  
pp. 533-539 ◽  
Author(s):  
Wen Xu ◽  
Yu Bin Hou
Keyword(s):  
Bearing Capacity ◽  
Large Diameter ◽  
Field Testing ◽  
Construction Method ◽  
Load Test ◽  
Test Field ◽  
Static Load Test ◽  
Pipe Pile ◽  
Bored Pile ◽  
Bearing Behavior

Through field static load test and pile shaft axial force test, field testing study is conducted on bearing behavior of NAKS-construction-method belled large-diameter PHC pipe pile; besides, the test result is compared with that of hammering-method PHC pipe pile and bored pile with same pile length and diameter under the same site condition. The result shows that the ultimate bearing capacity of NAKS-construction-method belled large-diameter PHC pipe pile is slightly inferior to hammering-method PHC pipe pile but obviously superior to that of bored pile. Compared with traditional hammering-method pipe pile, the pile side resistance of NAKS-construction-method belled pipe pile is smaller; however, the higher toe resistance will give better play to bearing capacity of bearing stratum of pile toe; moreover, it is found that under the action of ultimate load and failure load, the maximum settlement and final settlement of NAKS-construction-method belled pipe pile tip are obviously lower than that of other test piles, which is conductive to lessening foundation settlement of upper structure.

scholarly journals Development Study of T-Z Curve Generated from Kentledge System and Bidirectional Test

UKaRsT ◽  
2021 ◽  
Vol 5 (1) ◽  
pp. 17
Author(s):  
Nisa Utami Rachmayanti ◽  
Paulus Pramono Rahardjo
Keyword(s):  
Skin Friction ◽  
Test Methods ◽  
Load Test ◽  
Primary Data ◽  
Pile Test ◽  
Bored Pile ◽  
Loading Tests ◽  
Pile Load Test ◽  
Result Analysis ◽  
Z Curve

Pile loading tests to check the bearing capacity to support large loads. We can also use it to measure its deflection under lateral load.  There  are  two  tests:  the  axial  static  pile  load  test (Kentledge)  and  the  two-directional  static  pile  load  test (Bidirectional).  T-Z  curve  as  the  result  analysis  based  on  the instrumented  pile  test  data  describes  the  load  distribution  and mobilized skin friction along with the pile. Numbers of Vibrating Wire  Strain  Gauge  (VWSG)  mounted  in  several  depths  of  the bored  pile  and  two  tell-tale  on  top  and  toe  of  the  pile  used  as primary  data  in  this  research.  This  research  to  determine  the different  distribution  of  mobilized  skin  friction.  The  pile  from two different pile load test methods from the calculated t-z curve as  the  study  developed  from  both  methods  of  pile  test.  The research results that the kentledge system has bigger mobilized skin friction than in bidirectional test.

scholarly journals Ultimate Load Tests on Bearing Behavior of Large-Diameter Bored Piles in Weathered Rock Foundation

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Xiaoyu Bai ◽  
Xueying Liu ◽  
Mingyi Zhang ◽  
Yonghong Wang ◽  
Nan Yan
Keyword(s):  
Bearing Capacity ◽  
Limit State ◽  
Large Diameter ◽  
Diameter Ratio ◽  
Load Test ◽  
Single Pile ◽  
Rock Foundation ◽  
Deformation Characteristics ◽  
Lateral Resistance ◽  
Bored Piles

Based on the vertical compressive static load test and pile mechanics test of three large diameter bored piles (one of the test piles was treated with postgrouting) in granite gneisses foundation, the bearing capacity, deformation characteristics, and influencing factors of the single pile under the limit state are analyzed and compared with the recommended values of survey report and the recommended values of current codes. By comparing the measured and theoretical values of pile axial force, the bearing capacity of cast-in-place pile under normal and limit conditions is analyzed. The experimental results show that the Q-s curve of large-diameter rock-socketed mud wall retaining bored pile with a length-diameter ratio of 25–33 and rock-socketed depth of 5–8 d shows a rapid growth. After grouting treatment, the ultimate compressive bearing capacity of single pile is improved, the maximum settlement is reduced by 6.6%, the rebound rate is reduced by 11.1%, and the settlement effect of controlling pile top is not significant. The bearing capacity and deformation characteristics of the three test piles are less affected by length-diameter ratio and rock-socketed depth. For postgrouting piles, the ratio of frictional resistance of rock-socketed segment and the ratio of pile lateral resistance are less affected by length-diameter ratio and rock-socketed depth, while, for postgrouting piles, the ratio of pile lateral resistance is more affected by rock-socketed depth. The pile end resistance ratio of the three test piles is significantly affected by the rock-socketed depth, whether or not the pile side postgrouting treatment is carried out.

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