Research on seismic design method of buildings based on uniform collapse risk

In order to develop a seismic design method based on the uniform collapse risk, the characteristic parameters and control level of the earthquake collapse risk of building were examined, and it is pointed out that, during engineering design and control, the inelastic inter-story drift limit by the code GB 50011-2010 can be used as the collapse criteria, and the seismic collapse risk of the building can be characterized by the probability of the exceedance of the inter-story drift limit, and the risk control level is recommended to take as 10%. Secondly, the seismic design method based on uniform seismic hazard is studied, and it is suggested that the seismic parameters with exceeding probability of 2%/50yr of each intensity area should be regarded as the upper bound of the fortification of building collapse, that is, the third level parameters of building fortification, multiplied by 1/1.5 and 1/4.5, respectively, can be as the design parameters of the second level and the first level. Thirdly, the adjustment scheme of the main control measures affecting the risk of building collapse is studied, and some suggestions are put forward to modify the provisions, such as taking the inter-story drift limit of RC frame structure to 1/100, further improving the minimum cross-sectional size of the frame column, reducing the limit for axial compression ratio of column, stipulating a maximum axial compression ratio of 0.75 under the representative value of gravity load, and stipulating a redundancy coefficient for seismic carrying capacity. Finally, according to the typical 6-layer RC frame structure, a series of trial designs and collapse risk analysis based on the uniform-risk seismic design method are carried out. The results show that if the structure is designed in strict accordance with the uniform-collapse-risk-based seismic design method proposed in this paper, the risk of collapse under the 2%/50yr probability earthquake can be effectively controlled, so the proposed seismic design method is appropriate and feasible. © 2022, Editorial Office of Journal of Building Structures. All right reserved.