Shaking table test of steel truss frame focusing on acceleration and strain response for post-earthquake buckling evaluation

Abstract

Large-span steel structures have been widely adopted in stadiums, airports, factories, and train stations because they provide a large space for multi-functional use. To ensure business continuity, post-earthquake damage surveys and structural status estimation of such important and large-spaced buildings have attracted increasing attention. Structural health monitoring of buildings using accelerometers is already in widespread use; however, measuring the acceleration response alone cannot directly estimate the damage of individual structural members. Another potential approach is to measure strain; however, its application to building structures is very limited. The goal of this study is to establish a method for quantitatively determining the damage of a large-scale truss structure immediately after an earthquake. Truss structure specimens were statically loaded or shaken by a shaking table to cause buckling damage, and the relationship between the changes in acceleration and strain response before and after buckling and the progress of the damage were investigated. The response properties of both acceleration and strain changed as buckling damage progressed. However, the strain amplitude measured on the chord members showed significant change according to the progress of buckling damage, while the changes in the predominant frequency and mode shape calculated from the acceleration response were small. It was shown that the observed out-of-plane deformation was almost linear to the strain response, indicating the possibility of quantitative assessment of damage by strain measurement.