Seismic Assessment Of An Reinforced Concrete Frame Building Structure Using Pushover Analysis & Time History Analysis

With the development of social and economic level, people’s awareness of earthquake disaster prevention increased gradually. The requirements of national code for seismic design of buildings are also increasing. Therefore, seismic assessment and assessment of existing building structures becomes particularly important.In this paper, a five-story reinforced concrete frame structure in Zhengzhou City was taken as an example, using the finite element software SAP2000, nonlinear static analysis and nonlinear dynamic time history analysis were carried out to evaluate the seismic performance of the building structure under various ground motion intensity. The main contents and conclusions are as follows:(1) The finite element model of the five-story reinforced concrete frame structure has been established.The calculated reaction forces and vibration periods of the original design structure and the finite element model were compared to verify the reliability of the finite element model.(2) The pushover analysis, using a uniform distribution of lateral force and the first mode proportional type loading mode, was put out to evaluate the seismic performance of the building structure under different ground motion intensity.The results show:The pushover analysis results of the above mentioned lateral force mode are basically consistent.The designed structure can meet the seismic code provisions (GB50011-2010). The difference is that, the story drift under uniformly distributed load type is smaller than that of the proportion of first mode type, while the story shear force under the proportion of first mode type is smaller than that of the uniformly distributed load type. Therefore, the two load modes need to be used in conjunction during a seismic performance assessment of similar multi-story reinforced concrete frame structures.(3) The time history analysis of the above mentioned building structure was carried out. The conclusions are similar to the pushover analysis results.(4) Comparing with the pushover analysis results and nonlinear dynamic time history analysis results, we can draw conclusions that the designed structure can meet the detailed requirments of the seismic code provisions (GB50011-2010). But the stories with sudden change in the lateral stiffness of the structure were relatively weak and should be be strengthened in detail.