Assessment of the bearing capacity of piles in soil, determined by static and dynamic load tests

2021 ◽  
Vol 143 (2) ◽  
pp. 252-260
Author(s):  
R.Е. Lukpanov ◽  
◽  
S.B. Yenkebayev ◽  
D.V. Tsigulyov ◽  
◽  
...  
Keyword(s):  
Bearing Capacity ◽  
Dynamic Load ◽  
Load Tests

scholarly journals Research on Bearing Capacity of Simply Supported Skew Bridge Based on Load Test

2021 ◽  
Vol 233 ◽  
pp. 03008
Author(s):  
Songhui Li ◽  
Honglei Li ◽  
Jinjin Gao
Keyword(s):  
Bearing Capacity ◽  
Dynamic Load ◽  
Mechanical Performance ◽  
Damping Ratio ◽  
Load Test ◽  
Measuring Point ◽  
Residual Deflection ◽  
Theoretical Simulation ◽  
Simply Supported ◽  
Load Tests

The purpose of this paper is to use static and dynamic load tests to evaluate the mechanical performance of a simply supported skew slab bridge and to evaluate its actual bearing capacity. Firstly, the Midas Civil software is used for theoretical simulation, and secondly, the deflection, strain, and dynamic response of the key section of the bridge are studied through static and dynamic load tests. Finally, the measured values and theoretical values are compared and analyzed. The results show that: under static load, the relative residual deflection and relative residual strain of the measuring point of the structure are between -13.8%～-0.4% and -16.7%～1.8% respectively; Under dynamic load, the first-order vertical natural frequency of the test section is 7.813, and the damping ratio is 0.0316, indicating that the bridge is in an elastic working state under the test load, and the stiffness and bearing capacity can meet the requirements of the current code.

Study on the Load Test of Old Bridge

2011 ◽  
Vol 250-253 ◽  
pp. 1422-1425
Author(s):  
Ping Zhang ◽  
Lei Wang ◽  
Dong Xiao Li
Keyword(s):  
Bearing Capacity ◽  
Dynamic Characteristics ◽  
Dynamic Load ◽  
Mechanical Characteristics ◽  
Working Condition ◽  
Load Test ◽  
Bridge Structure ◽  
Dynamic Tests ◽  
Load Tests ◽  
Static And Dynamic Tests

It may appear different diseases after years of operation on old bridges. In order to understand the actual working condition and the bearing capacity of the bridge, the static and dynamic tests are taken. It describes the principle and methods for the load test via taking Banlashan Arch Bridge for example in this paper. The stiffness, strength and dynamic characteristics of bridge structure are measured, and the maintenance and reinforcing schemes are proposed, according to the results of static and dynamic load tests. Through analyzing the tests, the data and information of bridge can be accumulated, and the mechanical characteristics of this kind of bridge are discussed.

Design and structural performance measurements of a novel multi-cantilever foil bearing

2014 ◽  
Vol 229 (10) ◽  
pp. 1830-1838 ◽  
Author(s):  
Kai Feng ◽  
Xueyuan Zhao ◽  
Zhiyang Guo
Keyword(s):  
Dynamic Characteristics ◽  
Dynamic Load ◽  
Dynamic Stiffness ◽  
Excitation Frequency ◽  
Viscous Damping ◽  
Equivalent Viscous Damping ◽  
Foil Bearing ◽  
Load Tests ◽  
Stiffness And Damping ◽  
Motion Amplitude

With increasing need for high-speed, high-temperature, and oil-free turbomachinery, gas foil bearings (GFBs) have been considered to be the best substitutes for traditional oil-lubricated bearings. A multi-cantilever foil bearing (MCFB), a novel GFB with multi-cantilever foil strips serving as the compliant underlying structure, was designed, fabricated, and tested. A series of static and dynamic load tests were conducted to measure the structural stiffness and equivalent viscous damping of the prototype MCFB. Experiments of static load versus deflection showed that the proposed bearing has a large mechanical energy dissipation capability and a pronounced nonlinear static stiffness that can prevents overly large motion amplitude of journal. Dynamic load tests evaluated the influence of motion amplitude, loading orientation and misalignment on the dynamic stiffness and equivalent viscous damping with respect to excitation frequency. The test results demonstrated that the dynamic stiffness and damping are strongly dependent on the excitation frequency. Three motion amplitudes were applied to the bearing housing to investigate the effects of motion amplitude on the dynamic characteristics. It is noted that the bearing dynamic stiffness and damping decreases with incrementally increasing motion amplitudes. A high level of misalignment can lead to larger static and dynamic bearing stiffness as well as to larger equivalent viscous damping. With dynamic loads applied to two orientations in the bearing midplane separately, the dynamic stiffness increases rapidly and the equivalent viscous damping declines slightly. These results indicate that the loading orientation is a non-negligible factor on the dynamic characteristics of MCFBs.

Driven cast-in-situ pile capacity: insights from dynamic and static load testing

2021 ◽  
Author(s):  
Kevin N. Flynn ◽  
Bryan A. McCabe
Keyword(s):  
Dynamic Load ◽  
Shear Stresses ◽  
Load Testing ◽  
Pile Capacity ◽  
Compression Load ◽  
Shaft Resistance ◽  
Pile Installation ◽  
Cast Concrete ◽  
Load Tests

Driven cast-in-situ (DCIS) piles are classified as large displacement piles. However, the use of an oversized driving shoe introduces additional complexities influencing shaft resistance mobilisation, over and above those applicable to preformed displacement piles. Therefore, several design codes restrict the magnitude of shaft resistance in DCIS pile design. In this paper, a series of dynamic load tests was performed on the temporary steel driving tubes during DCIS pile installation at three UK sites. The instrumented piles were subsequently subjected to maintained compression load tests to failure. The mobilised shear stresses inferred from the dynamic tests during driving were two to five times smaller than those on the as-constructed piles during maintained load testing. This was attributed to soil loosening along the tube shaft arising from the oversized base shoe. Nevertheless, the radial stress reductions appear to be reversible by the freshly-cast concrete fluid pressures which provide lower-bound estimates of radial total stress inferred from the measured shear stresses during static loading. This recovery in shaft resistance is not recognised in some European design practices, resulting in conservative design lengths. Whilst the shaft resistance of DCIS piles was underpredicted by the dynamic load tests, reasonable estimates of base resistance were obtained.

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