Study For Dynamical Behaviors Of Concrete Filled Rectangular Steel Tubes

In the paper, the main work is as follow:1. In this paper, 31 specimens of Concrete Filled Rectangular Steel Tube (CFRST) are tested under cycle loading, the main parameters are axial ratio, section height to width ratio and steel strength. The fabrication of specimens, the program and phenomenon of the experiment are described in detail, and the phenomenon of the experiment is interpreted also. Experimental hysteretic curves are compared with calculation results utilizing integral method, and agree well. The effects of these parameters on hysteretic behaviors, monotonic curves, elastic rigidity and ductility are analyzed according to P- A monotonic curve from the experiment.2. On the basis of the stress-strain models of determining the steel and concrete under dynamic actions, theoretical analysis for P- A monotonic and hysteretic curves of CFRST is performed by fiber model method, and the theoretical results agree well with those of tests. According to monotonic P- relations for CFRST, the parameters such as axial compression ratio, slenderness ratio, steel ratio, steel strengh and concrete strength, which affect P- hysteretic curves, are analyzed.3. P- restoring force model, simplified calculation methods of ductility coefficient and energy dissipation are given on the basis of integral calculation and parameter analyze for CFRST. The comparisons between calculation results from P- restoring force model and hysteretic curves utilizing integral method show that they agree well. The parameters which affect ductility coefficient and energy dissipation are analyzed, and ductility coefficient of ordinary beam-columns are tabulated.