The Fracture Limit of Steel-Frame Members Under Dynamic Repeated Loads Through the Shaking Table Test

Abstract

Recently, much larger earthquakes are considered in the seismic designs of steel-frame structures in Japan. Under these severe ground motions, it is expected that not only the elasto-plastic deformation but also the fracture of the structural members could occur during the earthquakes. And through these situations, the more advanced seismic design or evaluation method which allow the partial destruction inside the structure and prevent from the worst-case scenario like the whole collapse are coming to be demanded. One of the ways to achieve this demand is considering the effects of not only the elasto-plastic deformation but also the fracture of structural members in the seismic analysis. In order for that, it is important to clarify the fracture limit of steel-frame members precisely under the dynamic load. Many static tests to clarify the members’ ultimate behavior were conducted in the past, but the dynamic tests were not well enough. In this research, the vibration tests were conducted to clarify the fracture limit of steel-frame members under the dynamic load. The behavior of the steel-frame members until the fracture was obtained by applying the repeated dynamic bending deformation with the shaking table. Also, The FEM analysis for the shaking table test results was conducted. Through the tests and the analysis study which simulates the test results, the mechanism of the member fracture occurred in the test under the dynamic loads were examined.