دانلود رایگان مقاله تحلیل سقوط بتن ستون لوله فولادی برای اتصالات تیر

Abstract

The multi-scale model which combined the fiber beam element with the fine element was used to investigate the progressive collapse performance of steel beam to concrete-filled steel tubular (CFST) column connections. By using the nonlinear static analysis method and taking into account the influence of the adjacent framework of joints, the resistance of progressive collapse, the failure modes and the stress distribution revealed the resistance mechanism of these joints during the process of progressive collapse. And the vertical displacement time history curves of joints which displayed the progressive collapse resistance demands of these joints were obtained by using the nonlinear dynamic analysis method. The relationship between resistance capacity and resistance demand of these joints were obtained by analyzing the nonlinear static analysis results and the nonlinear dynamic analysis results. These analysis results showed that the frame structure with these joints which enabled to form the resistance mechanism and new alternate path of unbalanced loads can prevent the occurrence of progressive collapse after the failure of column connected to joints. And the adjacent framework can improve the ability of anti-progressive collapse of these joints.

7. Conclusions

This paper presented the progressive collapse analysis of the steel beam to the CFST column connections by using multi-scale model. In hese investigations, the authors used both the nonlinear static method and nonlinear dynamic method to conduct analysis. Several conclusions can be drawn in this paper: (1) There are 4 phases of resistance mechanism of joints: beam mechanism, mixed mechanism, catenary mechanism and failure. The catenary mechanism plays a vital role in the resistance of progressive collapse. (2) By using the nonlinear static analysis, the failures of joints are located at connection between the steel beam and ring plate during the progressive collapse process. Due to the tension function of the neighboring frame structure, these joints can provide more resistance to prevent the occurrence of progressive collapse. (3) By using the dynamic analysis, the resistance demand can be obtained. Comparing the nonlinear dynamic analysis results with the nonlinear static analysis results, it has showed that joints should have a strong connection between the steel beam and CFST column. The quality of the connections is key factor for frame structure to resist the progressive collapse.