Damage identification of piles based on vibration characteristics.

Xiaozhong Zhang,Dewen Liu,Wenjuan Yao,Bo Chen

doi:10.1155/2014/150516

Xiaozhong Zhang, Dewen Liu + Show 2 more

Open Access

https://doi.org/10.1155/2014/150516

Copy DOI

Abstract

A method of damage identification of piles was established by using vibration characteristics. The approach focused on the application of the element strain energy and sensitive modals. A damage identification equation of piles was deduced using the structural vibration equation. The equation contained three major factors: change rate of element modal strain energy, damage factor of pile, and sensitivity factor of modal damage. The sensitive modals of damage identification were selected by using sensitivity factor of modal damage firstly. Subsequently, the indexes for early-warning of pile damage were established by applying the change rate of strain energy. Then the technology of computational analysis of wavelet transform was used to damage identification for pile. The identification of small damage of pile was completely achieved, including the location of damage and the extent of damage. In the process of identifying the extent of damage of pile, the equation of damage identification was used in many times. Finally, a stadium project was used as an example to demonstrate the effectiveness of the proposed method of damage identification for piles. The correctness and practicability of the proposed method were verified by comparing the results of damage identification with that of low strain test. The research provided a new way for damage identification of piles.

Highlights

In practical engineering, the quality of piles was influenced by various factors, including the conditions of geotechnical engineering, structural design, construction quality, and the surrounding environment
Chen [5] researched the application of core drilling method to test pile damage, but this method was not able to accurately judge the fracture and the development of piles foundation in service
Wu et al [8] proposed an approach to test the damage of foundation piles with a combination of applications of core drilling method, ultrasonic transmission method, and low strain integrity testing

Summary

Introduction

The quality of piles was influenced by various factors, including the conditions of geotechnical engineering, structural design, construction quality, and the surrounding environment. It was demonstrated that the index Δφi was more sensitive to the damage severity when compared with the similar index calculated by displacement eigen parameter Another damage detection method focused on the decrease of modal stain energy between two structural degrees of freedom. Scientists have done a series of studies on structural damage detection with strain energy method, and they have achieved certain research results. Taking full advantages of the natural frequency on integral damage identification, the sensitivity of the element modal strain energy method on small injuries detection, and the efficient local analysis of Time domain and frequency domain of wavelet analysis, an identification method for locating the small injure of pile and measuring damage severity was established in this paper, of which the correctness and efficiency were demonstrated by engineering application examples

Basic Theory

Example Verification

Findings

Conclusions