Investigation on steel-concrete composite frame in Chinese traditional style buildings by pseudo-dynamic test

Abstract

A series of pseudo-dynamic tests of a 1/2-scale 1-story 3-bay Chinese traditional style frame using steel - concrete composite columns was performed. During the test, the input ground motions were chosen from El Centro wave, Taft wave and Lanzhou wave. And peak ground acceleration (PGA) were 35 gal (minor earthquake of 7 degrees), 100 gal (precautionary earthquake of 7 degrees), 220 gal (major earthquake of 7 degrees) and 400 gal (major earthquake of 8 degrees), respectively. The failure modes, displacement and acceleration time history curves, hysteretic loops of restoring force- displacement, energy dissipation capacity and deformability, inter - story drift ratio of the test model were analyzed. It is shown that the typical failure modes of the model are concrete cracking at the connection between hypostyle column and penetrating tie as well as yield of longitudinal reinforcement of hypostyle column and peristyle column. And also, the model has better plastic deformation capacity. With a larger PGA, natural frequencies and dynamic amplification factors decreased, but its energy dissipation capacity increased. The energy dissipation of the model subjected to El Centro wave was largest with the same PGA. Based on the experimental results, the modal analysis and dynamic elasto-plastic analysis of the test model was performed using finite element software SAP2000. The results showed that under the action of horizontal earthquake, the 1st mode was translation of the model, and the plastic hinges of the model first formed on the ends of penetrating tie and successively developed at the root of hypostyle column, peristyle column, CRST-2 and CRST-3 and CRST-1 and CRST-4. And the inter-story drift ratios of the model subjected to 700 gal El Centro was close to the limited value in Chinese Code for Seismic Design of Buildings (GB50011-2010), indicating that the frame had a higher safety margin.