A SA-Based Wireless Seismic Stress Monitoring System for Concrete Structures

S. Hou 1 and Y. Yu 2 and H. B. Zhang 1 and X. Q. Mao 2 and J. P. Ou 1,3

Academic Editor:Gangbing Song

1, School of Civil Engineering, Dalian University of Technology, Dalian 116024, China
2, School of Electronic Science and Technology, Dalian University of Technology, Dalian 116024, China
3, School of Civil Engineering, Harbin Institute of Technology, Harbin 150090, China

Received 29 July 2013; Accepted 6 October 2013

This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

1. Introduction

In seismically active regions, acquisition of structural response data during earthquakes is essential to assist the evaluation of the current design practices [1]. Most of the existing seismic monitoring systems are based on the accelerometers [1-6]. However, damage detection using acceleration information is impractical due to the very heavy computational demands and the need for a detailed and accurate three-dimensional finite element model [2]. Thus, sensors that provide local damage information supplement the existing seismic monitoring systems nicely.

Traditional strain gauges like fiber Bragg Grating sensors and foil strain gauges, when embedded in a concrete structure, cannot measure the damage process reliably because their bondages with concrete tend to become loose. A commercially available load cell is able to measure the internal stress directly, but issues such as the size of the cell, its bondage with concrete, the interference it produces to the local stress field, and the cost hinder its application. The cement-based strain/stress sensors, which take advantage of the piezoresistivity effect developed by various researchers for internal stress/strain measurement [7-10], unfortunately can only be used when the building structure is in a uniaxial and elastic stress/strain state. A cement-based smart aggregate (SA) with a d₃₃ -mode lead zirconate titanate (PZT) patch embedded in it was proposed by Song et al. [11]. By evaluating the wave propagation among SAs, it can detect the cracking level of the structure in a qualitative manner [12-15]. The application of SA has also been extended to measure the compressive stress monitoring by calibrating the SA to only relatively low stress levels [16, 17]. To monitor the full damage process of concrete structures, Hou...