scholarly journals USING THE STRESS-WAVE THEORY TO DETERMINE THE BEARING CAPACITY OF PILES

2019 ◽  
Vol 10 (3) ◽  
pp. 35-43
Author(s):  
I. V Ofrikhter ◽  
A. B Ponomaryov
Keyword(s):  
Lower Bound ◽  
Dynamic Test ◽  
Wave Theory ◽  
Driven Piles ◽  
Usual Practice ◽  
Pile Testing ◽  
Lower Bound Solution ◽  
Test Database ◽  
Practical Recommendations ◽  
Attention To Detail

High strain dynamic pile testing is usual practice, and has many benefits that make its use highly attractive. However, it requires careful preparation, specific equipment, attention to detail and testing engineer skill to properly perform these tests. Engineer skills for testing largely determines the non-proliferation of the method in Russia. Without of understanding wave equation analyses, the test engineer may not realize when results are valid, or when capacity results may be only a lower bound. It is widely known that the capacity of driven piles may change with time after installation and for that reason restrike tests are generally recommended. It is also generally stated that the set per blow should be at least 2 mm, or otherwise the dynamic test may only yield a lower bound solution. To confirm or refute these recommendations, an analysis of the existing test database was conducted, as well as an analysis of the tests performed at the Perm region facilities. The article presents the conclusions of this analysis and practical recommendations.

Lower-Bound Solution Algorithm for Equilibrium Signal-Setting Problem

2008 ◽  
Vol 2085 (1) ◽  
pp. 104-110 ◽  
Author(s):  
Kaveh F. Sadabadi ◽  
Hedayat Zokaei-Aashtiani ◽  
Ali Haghani
Keyword(s):  
Lower Bound ◽  
Descent Method ◽  
Solution Algorithm ◽  
Network Design Problem ◽  
Steepest Descent Method ◽  
Optimal Flow ◽  
Solution Algorithms ◽  
Global Optima ◽  
Equilibrium Network Design ◽  
Lower Bound Solution

The equilibrium signal-setting problem is stated and subsequently formulated as a continuous equilibrium network design problem. The bilevel formulation is nonconvex and therefore cannot be solved for global optima by using descent solution algorithms. Therefore, a lower bound using a system optimal flow pattern is proposed that will be quite tight in both uncongested and highly congested network traffic situations. A solution algorithm based on the standard steepest-descent method is proposed for the lower-bound problem. Performance of the solution algorithm on a network problem is reported.

Analysis of Pile-Soil Interaction by Computer Simulation

2006 ◽  
Vol 326-328 ◽  
pp. 1531-1534 ◽  
Author(s):  
Guang Zhang ◽  
Dong Zi Pan ◽  
Jing Xi Chen ◽  
Ai Fang Zhou
Keyword(s):  
Computer Simulation ◽  
Numerical Model ◽  
Stress Wave ◽  
Dynamic Test ◽  
Wave Theory ◽  
One Dimension ◽  
Concrete Piles ◽  
The One ◽  
Reflection Characteristics

In this paper, a numerical model to simulate the interaction of pile-soil based on the one-dimension stress wave theory is established, which can provide the propagating process and reflection characteristics of stress wave under impulsed load in concrete piles. The simulation is carried on about the stress wave in integrated pile and defective pile, which provide all kinds of the propagating characteristics. It can enhance the accuracy of dynamic test. The validity of this approach is verified through the comparison of the measured curve and the simulated curve.

Using Dynamic Pile Testing To Evaluate Quality and Verify Capacity of Driven Piles

1998 ◽  
Vol 1633 (1) ◽  
pp. 117-119
Author(s):  
Phillip A. Walton ◽  
Stephen L. Borg
Keyword(s):  
New York ◽  
New York State ◽  
Field Performance ◽  
Testing Procedure ◽  
Nondestructive Method ◽  
Test Method ◽  
York State Department ◽  
Driven Piles ◽  
Pile Testing ◽  
Stress Damage

Pile testing using a pile driving analyzer is a nondestructive method of evaluating the support capacity provided by the soil to a pile. The New York State Department of Transportation’s (NYSDOT) approach to incorporating this testing procedure into a project is discussed from design into construction. Specification and contractural responsibilities are addressed, as are typical applications of the test method. By judiciously using dynamic pile testing, NYSDOT is able to cost-effectively link the design process to construction. Informed decisions are possible regarding the field performance of driven piles with respect to pile-soil support capacity, hammer operation, driving stress, damage to piles during driving, and verification of assumptions made for wave equation analysis of piles.

scholarly journals Lower Bound Solution of Foundation Bearing Capacity beneath Strip Footing Based on Parabolic Mohr Failure Criterion

2020 ◽  
Vol 2020 ◽  
pp. 1-8
Author(s):  
Fang Wei ◽  
Shi Li-jun
Keyword(s):  
Lower Bound ◽  
Stress Field ◽  
Bearing Capacity ◽  
Yield Criterion ◽  
Rock Foundation ◽  
Allowable Stress ◽  
Bound Solution ◽  
Loading Tests ◽  
Lower Bound Solution ◽  
Two Parameter

The static allowable stress field of foundation under strip foundation is constructed by means of stress columns, and the calculation method of the lower bound foundation bearing capacity based on the two-parameter parabolic Mohr yield criterion is proposed. Moreover, the influence of the amount of stress columns and material mechanical parameters on the lower bound bearing capacity is analyzed. The results show that a better solution can be obtained by optimizing the static allowable stress field. However, the improvement of lower bound solution might be inefficient if the stress column amount is large enough. The stresses of the superimposition area show a reduction with the improvement of stress field; on the other hand, the superposed stresses are enhanced ever faster as the involved stress column increases. The tensile-compressive strength ratio has a moderate effect on the lower bound solution. Finally, the reliability of the proposed method is verified by some rock foundation loading tests.

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