Study On The Progressive Collapse Of Reinforced Concrete Frame Structure In Earthquake Zone Based On The Reliability

It has almost been half a century to focus on the study of structural progressive collapse or disproportionate collapse. In recent years, it becomes a hot spot to study the progressive collapse under accidental load such as explosion, earthquake, fire etc., which may lead to severe consequences. The concerning of progressive collapse on previous code is all qualitative regulation, thus generating various expressions to the cause of progressive collapse and colorful research methods, which have not unified recognition and standard. The research on progressive collapse based on reliability would bring vitality, insight, and new solutions to the progressive collapse study. The reliability index and failure probability of structural member and system are studied on the basis of reliability theoretical analysis methods. To sum up, the main work accomplished and conclusions are as follows:1The research background at home and abroad was briefly introduced, which included the concept of progressive collapse, the application and development of structural reliability theory, the related basic concepts, the determination of various random variables and their distribution patterns.2The object of study was a three-story reinforced concrete frame structure which was designed by PKPM. The anti-seismic reliability vector model was built and the reliability vector of each story was achieved. The51sections of a product of frame were calculated and analyzed. Through a large number of calculations, various load effect values were obtained. Then the max combining class was selected among composite values. The reliability index of normal section and oblique section of each section was obtained through bearing capacity limited state equations. The section that the damage occurred was found according to the reliability index.3The branch of global critical strength-approximately bound method was used to determine the main failure mode. The overall failure probability of structure system was calculated by new method. The conclusion was that the possibility of structure progressive collapse under frequent seismic actions was small.4The seismic wave peak, the earthquake duration, the selection of the number of seismic methods and the structural damage criterion were determined. The mode of three-story reinforced concrete frame structure which was designed by PKPM was built by the finite element analysis software of ABAQUS. Three different amplitudes of seismic waves were applied to the horizontal direction Y of the structure. Then the structure response and destruction were observed under different seismic. The results showed that structure progressive collapse could hardly happened under frequent seismic actions, however in the right center column among the selected frame, its interlaminar displacement was close to the limit of interlaminar displacement. It also showed that structure progressive collapse could happen under infrequent seismic actions. Finally, combined with the destructed process and the calculated results, the advice was given on how to prevent progressive collapse of reinforced concrete frame structure concerning the problems which were likely to occur.