بررسي رفتار ستون هاي فلزي پرشده با بتن به روش اجزاء محدود غيرخطي

BEHAVIOR ANALYSIS OF CONCRETE FILLED STEEL BOX COLUMNS BY USING NONLINEAR FINITE ELEMENT METHOD

Being economical and performing very well under cyclic (seismic) loads, steel sections filled with concrete have had a large application in structural buildings. Extensive studies and experiments have been conducted on such members to investigate the influence of different parameters and loading on the behavior of these structural components. In this paper, at first based on the data available from previous experiments and studies, the behavior of composite columns is discussed. Then, the results of non-linear finite element analysis of thin-walled steel sections filled with concrete are presented. Finally, a comparison between the finite element analysis results and the experimental data available on the specimens is made. Then, using trial and error method, the finite element model is calibrated. The capacities of the sections are also calculated based on LRFD design method and the results are compared with the two sets of already available data. Because of the increase in the use of high strength materials in structures, the effect of the increase in concrete and steel strengths has been discussed in this paper. Also, the effects that the change in the thickness of the steel shell may have had on the behavior of composite columns are argued. In the finite element model, solid elements for the concrete core, shell elements for the steel section and contact element for the interface were hired to create a true representation of the member. Contact elements were used to model the bond between the concrete core and the steel shell.