Probability Quantizing Of Vertical Irregular Control Parameters For Concrete Frame Structures

Probability quantization process includes the deformation demand forecast ofstructure and the deformation capacity check. At present, the study of verticalirregular control parameters still remains in the semi-empirical level. Due to the smallprobability and strong uncertainty of earthquake action, it is necessary to execute thequantitative assessment of vertical irregular seismic control effects in seismic code.This paper employs the multi-storey RC (reinforced concrete) frame structures byelastic-plastic dynamic time history analysis, and develop the seismic displacementresponse analysis of the vertical irregular RC frame structures subjected to strongground motions; then analyze the variation tendency of the maximum inter-storeydisplacement with vertical irregular factors and the failure probability exceeding limitstate standards based on Monte Carlo simulation method, moreover, probability offailure analysis is adopted to quantify the control effects of vertical irregularparameters. The following are my main research contents:1. Employing5-storey and10-storey frame structures with vertical irregularstorey strength and stiffness at the first storey and middle storey, and adopting eightground motion records from Chi-Chi earthquake, nonlinear dynamic time historyanalysis are performed to investigate the difference of structural seismic displacementresponse. The results show that the influence of strength irregularities on structuralseismic displacement response is greater than the stiffness irregularities.2. Taking5-storey and10-storey frame structures as the research objects, thestudy of structural seismic displacement response under strong earthquake areinvestigated. From elastic-plastic dynamic time history analysis, the influence ofvertical irregular parameters on the maximum (and the second largest) inter-storeydisplacement demand is analyzed. The results show that the strength and stiffnessirregularities have great influence on the maximum inter-storey displacement, whichincreases with decreasing of the vertical irregular factors for the first story, whiledecreases with decreasing of the vertical irregular factors for the middle storey. Inaddition, the variation tendency of second largest inter-storey displacement is similarto the maximum.3. Investigation on the failure probability of frame structures with verticalirregularity subjected to strong ground motions. Considering random property of earthquake ground motions, and adopting the extracting value by the extreme type Ⅲdistribution, the irregularities are in strength and stiffness in the first and middlestorey of structures. An elastic-plastic dynamic time history analysis is performed toget the corresponding inter-storey displacement response. Moreover, the failureprobability exceeding limit state standards is analyzed. The results show that verticalirregularities have significant influence on the structural failure probability exceedinglimit state standards, which increases with decreasing of the vertical irregular factors.