Numerical Assessment of Factors Affecting Waveform Based on Low Strain Testing of Piles
In this paper dynamic testing of piles using the low strain method is performed by means of numerical analyses based on solid finite element model. To this end, velocity-time curves are presented investigating the influence of various parameters such as mesh density, impulse width, receiving point, and soil modulus on the waveform characteristics. Then, find regularity of waveform affected by different parameters to provide reference of the real project detection.
Proposal of a new system to classify possible damages in piles partially reinforced considering the results of low strain integrity tests
Abstract Low strain integrity tests in piles are relatively cheap, of quick execution and nondestructive. Despite all these advantages, several variables are involved and the influence of external factors can complicate the interpretation of the results. Between them, the influence of the pile reinforcement can be high lighted. In piles partially reinforced, the difference in density and elastic modulus of the concrete in different parts of the pile and the influence of the process of introducing the reinforcement bars can induce some reflections in the test that can be confused with damage in the pile and, therefore, should be taken into account to analyze the tests results. In this research, the influence of the reinforcement embedded in the piles is analyzed using numerical (FEM) simulations and comparing them with tests made in the field. A new classification of possible damages is proposed based on the analysis of the reflections observed at the end of the reinforcement cage embedded in a pile partially reinforced.
Caisson Evaluation by Stress Wave Propagation Method
The theoretical aspects of wave propagation were verified in the laboratory by experiments on bars of aluminum and concrete which showed that it is possible to detect discontinuities and abrupt changes in the cross-sectional areas of long members. The theory is based on stress wave propagation in elastic solids and on the Rayleigh theory of surface waves. Field tests demonstrated that the method could be used for in-situ installations of caissons and piles, resulting in very little interference with normal construction operations. Basic data and records are presented for laboratory experiments on aluminum and concrete bars, and field tests on cast-in-place caissons and piles. The results indicate that the stress wave propagation method has the potential for providing a simple, rapid, inexpensive, and reliable method for detecting irregularities in caissons and piles.