Identification of residual force in static load tests on instrumented screw displacement piles

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Adam Krasiński ◽  
Mateusz Wiszniewski
Keyword(s):  
Static Load ◽  
External Factors ◽  
Load Test ◽  
Necessary Condition ◽  
Measuring Instruments ◽  
Test Results ◽  
Pile Shaft ◽  
Load Tests ◽  
Residual Force ◽  
Proper Interpretation

Abstract Occurrence of the so-called residual force of an unknown value significantly disturbs interpretation of static load tests performed on piles equipped with additional measuring instruments. Screw displacement piles are the piling technology in which the residual force phenomenon is very common. Its formation mechanism is closely related to the installation method of this type of piles, which initiates generation of negative pile skin friction without any additional external factors. Knowledge of the value and distribution of a residual force (trapped in a pile shaft before starting the load test) is a necessary condition for the proper interpretation of instrumented pile test results. In this article, a clear and easy-to-use method of residual force identification, based on the analysis of shaft deformations recorded during pile unloading is presented. The method was successfully verified on two pile examples and proved to be effective and practical.

scholarly journals Evaluation of Deformation Characteristic of Railway Subgrade Using Reinforced Rigid Walls with Short Reinforcement under Repetitive and Static Loads

2021 ◽  
Vol 11 (8) ◽  
pp. 3615
Author(s):  
Ungjin Kim ◽  
Dae Sang Kim
Keyword(s):  
Static Load ◽  
Deformation Characteristic ◽  
Horizontal Displacement ◽  
Rigid Wall ◽  
Load Test ◽  
Test Results ◽  
Static Loads ◽  
Load Tests ◽  
Vertical Spacing ◽  
Rigid Walls

A full-scale reinforced subgrade for railways (RSR) was constructed, and repetitive and static load tests were performed to analyze the deformation characteristics of reinforced rigid walls with short reinforcements for railway subgrades that require strict displacement restrictions. Load test results were obtained for four sections, in which the reinforcement arrangement (vertical spacing and length) and wall-reinforcement connection method were applied differently, and the behavior of the reinforced rigid wall was observed according to each parameter. A repetitive load of 500 kPa and a static load of 1000 kPa were applied to the outside of the reinforcement area to evaluate the behavior of the subgrade when utilizing short reinforcement. The test results confirmed the reduction of the settlement and horizontal displacement of the wall, owing to the restraining effect of the short reinforcement and rigid wall. In addition, it was observed that the greater the applied load, the greater the influence of the reinforcement on the behavior of the subgrade; this pattern was more marked in loads above the yield of soil.

Field static load tests on drilled shaft founded on or socketed into rock

2000 ◽  
Vol 37 (6) ◽  
pp. 1283-1294 ◽  
Author(s):  
Caizhao Zhan ◽  
Jian-Hua Yin
Keyword(s):  
Bearing Capacity ◽  
Static Load ◽  
Large Diameter ◽  
Load Test ◽  
Drilled Shaft ◽  
Test Results ◽  
Static Load Test ◽  
End Bearing Capacity ◽  
Side Resistance ◽  
Load Tests

The Mass Transit Railway Corporation proposes to construct the Tseung Kwan O Depot (TKD) within Area 86 reclamation at Tseung Kwan O as part of the Tseung Kwan O Extension. The proposed foundation for the TKD comprises about 1000 large-diameter, bored, cast in situ, drilled shafts founded on or socketed into rock. To confirm the design allowable end bearing capacity and rock socket side resistance for the drilled shaft foundations, two test piles were constructed and tested. Both test piles were instrumented with strain gauges and rod extensometers. This paper presents the static compressive load test results on both test piles. The test results indicate that an end bearing capacity of 20.8 MPa (design allowable 7.5 MPa) and rock socket side resistance 2.63 MPa (design allowable 0.75 MPa) are achieved during the pile load tests with no sign of failure.Key words: drilled shaft, static load test, end bearing capacity, rock socket, rock socket side resistance, load transfer.

Research on Static Load Tests of Damaged Bridge Strengthened with Pre-Stressed HFRP

2014 ◽  
Vol 1079-1080 ◽  
pp. 258-265
Author(s):  
Chen Ning Cai ◽  
Shan He ◽  
Li Na Liu ◽  
Shi Kun Ou
Keyword(s):  
Static Load ◽  
Flexural Rigidity ◽  
Fiber Reinforced Polymer ◽  
Test Results ◽  
Structural Members ◽  
Fiber Reinforced ◽  
Hybrid Fiber ◽  
Reinforced Polymer ◽  
Glass Fiber Reinforced ◽  
Load Tests

Thispaper presents an experimental study to strengthen an existing bridge usingpre-stressed carbon fiber reinforced polymer (CFRP) and glass fiber reinforced polymer(GFRP) materials. The method using pre-stressed hybrid fiber reinforced polymer(HFRP) to strengthened structural members is an emerging pre-stressed strengtheningtechnology. In this study, experimental data selected from result of staticloading test conducted to hollow slabs with CFRP/GFRP has been compared with specimenswithout strengthening. Test results showed that the strengthening methoddeveloped in this study could effectively reduce the stress in hollow slab,improving the flexural rigidity and inhibiting the concrete from fracture.

Static Load Test of Frame-Structure Slab

2013 ◽  
Vol 790 ◽  
pp. 227-230
Author(s):  
Jian Feng Su ◽  
Yu Feng Xu
Keyword(s):  
Carrying Capacity ◽  
Static Load ◽  
Load Test ◽  
Frame Structure ◽  
Test Results ◽  
Static Load Test ◽  
Important Method ◽  
Floor Slab ◽  
Testing Scheme

Floor slab static load test is a important method to judge the performance and carrying capacity of the slab. This paper, with the background of a factory frame-structure slab, introduced the testing scheme, the details of the testing process as well as the test results. The testing cases provide a useful reference for the same type of project.

Prediction method of bridge static load test results based on Kriging model

2020 ◽  
Vol 214 ◽  
pp. 110641 ◽  
Author(s):  
Pengzhen Lu ◽  
Zijie Xu ◽  
Yangrui Chen ◽  
Yutao Zhou
Keyword(s):  
Static Load ◽  
Prediction Method ◽  
Kriging Model ◽  
Load Test ◽  
Test Results ◽  
Static Load Test

scholarly journals First results of pipe pile static load test in small laboratory scale

2018 ◽  
Vol 251 ◽  
pp. 04038 ◽  
Author(s):  
Michal Baca ◽  
Jaroslaw Rybak
Keyword(s):  
Static Load ◽  
Axial Loading ◽  
Laboratory Scale ◽  
Load Test ◽  
Scale Model ◽  
Small Scale ◽  
Small Laboratory ◽  
Static Load Test ◽  
First Results ◽  
Load Tests

Presented laboratory testing program of tubular steel piles is a part of a bigger research program which contained static load tests in full scale and numerical simulations of conducted research. The main goal of the research is to compare static load tests with different working conditions of a shaft. The presented small scale model tests are the last part of the research. The paper contains the testing methodology description and first results of model pile axial loading. The static load tests in a small laboratory scale were conducted in a container filled with uniformly compacted medium sand (MSa). The first results of the investigation are presented in this paper, with the comparison of two pile capacities obtained for different roughness of the pile shaft (skin friction). The results are presented as load-displacement curves obtained by means of the Brinch-Hansen 80% method.

scholarly journals Bi-Directional Static Load Tests of Pile Models

2020 ◽  
Vol 10 (16) ◽  
pp. 5492
Author(s):  
Michał Baca ◽  
Włodzimierz Brząkała ◽  
Jarosław Rybak
Keyword(s):  
Bearing Capacity ◽  
Static Load ◽  
Load Testing ◽  
Pile Capacity ◽  
Pile Shaft ◽  
Load Tests ◽  
S Curve ◽  
Definition Of ◽  
Standard Tests ◽  
Static Load Testing

This work examined a new method of bi-directional static load testing for piles, referencing the Osterberg test. Measurements were taken, on a laboratory scale, using six models of piles driven into a box filled with sand. This method allowed for separate measurements of pile base and pile shaft bearing capacities. Based on the results, the total pile bearing capacity and equivalent Q–s diagrams were estimated. The results obtained show that the structure of the equivalent curve according to Osterberg is a good approximation of the standard Q–s curve obtained from load tests, except for loads close to the limit of bearing capacity (those estimates are also complicated by the inapplicability and ambiguity of a definition of the notion of limit bearing capacity); the equivalent pile capacity in the Osterberg method represents, on average, about 80% of the capacity from standard tests.

Study on the Crack in Concrete Flange of Outer-Plated Steel-Concrete Continuous Composite Beams

2012 ◽  
Vol 166-169 ◽  
pp. 1023-1028 ◽  
Author(s):  
Li Hua Chen ◽  
Qi Liang Jin ◽  
Haiyu Si
Keyword(s):  
Crack Width ◽  
Static Load ◽  
Bending Moment ◽  
Structural Features ◽  
Composite Beams ◽  
Test Results ◽  
Load Tests ◽  
Reversed Loading ◽  
Negative Bending ◽  
Stress Block

Static load tests were conducted on two reversed-loading simply supported and two continuous outer-plated steel-concrete composite beams to study the formation and development of cracks in such beams under negative bending moment. The test results show that based on the plane section assumption, it is an effective and economical method to calculate the cracking moment of the composite beams assuming a rectangular stress block for concrete in tension zone. Considering the structural features of outer-plated steel-concrete composite beams, the formula for calculating crack width of concrete flange of outer-plated steel-concrete composite beams is discussed and presented, and the calculated values of crack width agree well with the experimental results.

scholarly journals Static and Dynamic Load Tests of Shaft and Base Grouted Concrete Piles

2017 ◽  
Vol 2017 ◽  
pp. 1-11 ◽  
Author(s):  
Jialin Zhou ◽  
Xin Zhang ◽  
Hongsheng Jiang ◽  
Chunhao Lyu ◽  
Erwin Oh
Keyword(s):  
Dynamic Load ◽  
Static Load ◽  
Test Results ◽  
Pile Capacity ◽  
Friction Resistance ◽  
Concrete Piles ◽  
Double Tangent ◽  
Load Tests ◽  
Bored Piles ◽  
Comparison Of The Results

This paper examines shaft and base grouted concrete piles by conducting vertical static load tests (SLTs) and dynamic load tests. Three concrete piles with shaft and base grouting, with base grouting only, and without grouting techniques were selected, and compressive SLTs were conducted. Two piles with grouting were also assessed with dynamic load tests. Another two uplift SLTs were conducted to one shaft and base grouted pile and one pile without grouting. Traditional presentations were provided to check whether the bored piles reached the design requirement. Interpretations of test results were also provided to determine the ultimate pile capacity. Results from these 5 SLT programs indicated that double-tangent and DeBeer's methods are close to each other, and Chin's method overestimates the pile capacity. Comparison of the results from the SLTs and dynamic load tests shows that the results from Chin's method are close to dynamic results, and Mazurkiewicz's method overestimates for friction resistance. The results also demonstrate that base and shaft grouted pile and base grouted pile increase by 9.82% and 2.89% in compressive capacity, respectively, and compared to the uplift SLTs; there is a 15.7% increment in pile capacity after using base and shaft grouting technology.

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