Experimental Studies On Progressive Collapse Prevention (Bend) Of Reinfored Concrete Frame

Building maybe encounters incidental load caused by some incidents during the usage period. Explosion caused by gas or bomb, and bump caused by aerocraft or large camion are the main reasons to lead to incidental load. The incidental load may cause part breakage of the building. If the sturcture system could not dissipate the energy or prevent the development of destruction, there would be some chain reactions in vertical or horizontal of the structure. Sequentially the whole structure may collapse, there would be a huge loss in possession and personnel. Since the RC frame system is the most populer one to be used in our country, and the study about how it resists progressive collapse has more practical and applied worthiness.This paper starts from the analysis of the route of load-bearing, and analyzes how RC frame resists progressive collapse in both statics mechanism and dynamice response. If one middle column is destroyed, the vertical load of the prime column borne must be redistributed in horizontal by the beams above the destroyed column, then the beams become the key elements in research of resisting progressive collapse, and to the sudden load, it is practical and reseanable to choose the beams as the specimens to study. The experimentation focuses on eight beams which is divided as three groups, and the work includes: studying the capacity of the beam designed as Code for Seismic Design of Buildings and studying the effect of both steel percentage and stirrup percentage.From the analysis of test data, it can be concluded that there is different response according to different load. With the arching action, the dynamic bend capacity of beam can be elevated 50%, and the beam designed as Code for Seismic Design of Buildings can accomplish resisting collapse. If there is no shear failure, redistribution of internal forces can be done. The effect on the capacity of bend and shear in RC beam are pointed out.This subject is from the project of study of reinforced concrete frame buildings to resist progressive collapse, supported by State Science Fund (No.50478114).