Square Cfst Column Low Cyclic Experimental Study And Finite Element Analysis

Concrete filled steel tubular (CFT) structures are rapidly emerging as one of the dominant structural systems in the construction industry in recent decades duo to the excellent earth-quake resistant properties, particularly for the earthquake resistance. At the same time, strength and behavior of CFT structures have been investigated in many countries. However, most of these researches are concentrated on concrete fillded circular steel tubar structures. Rearches on concrete filled square steel tubular(CFSST) structures are lacking in contrast to concerete filled circular steel tubular structures, and accumulation on that concrete filled square steel tubular(CFSST) structures resist earth-quake is especially lacking. So it is necessary to make more experimental research on CFSST structures deeply.In this paper, properties of concrete-filled square steel tublar (CFSST) composite structure were studied under low-frequency, horizontal, repeat load. Low-frequency, horizontal, repeat load have been proceeded on the speciman of the CFSST frame by Electro-hydraulic servo loading system, to analyze ductility behavior and seismic energy, hysteretic curves to CFFST between displacements and repeat loads are shown. Theoretical research based on the quasi-static test such as theoretical analysis in nonlinear finite element method, in the end, separate model under constant axes pression and humdrum load, combinatorial model under constant axes pression and repeat load, which are built with computer simulation, computer simulation of the test with ANSYS is given, together with hysteretic curve of simulation. By contrasting and analyzing, the models of simulation were verified reasonable. At last, taking a practical project for example, composite structure with CFSST's ,spatial finite element model and structure with concrete including reinforcing steel bar were built, and also some parameters were chose about the calculation by the analytic results .On the basis of these, time-history analysis was separately applied on composite structure with CFSST and structure with concrete including reinforcing steel bar when uni-directional earthquake acting on them in order to study the different structual characteristics of two kinds of structual systems.According to the experimental results and the analysis results of this paper, it is clear that the structural of concrete filled square steel tubular is of the excellent structural advantages in ductibility and the excellent earth-quake resistant properties; studying the seismic performance of CFSST by the finite element, the effect of the bound between steel tube and concrete was considered by two kinds of models which considering slippage between steel tube and concrete or not, but the analysis results shows that two kinds of models have not distinctness for simulation. The 3-D nonlinear finite element model beam element can ensure high accuracy and it is recommended for conducting structure analysis of concrete filled square steel tubular. CFSST is of more favorable seismic performance than concrete including reinforcing steel bar, which can effectively ensure the safety of people and wealth...