不同设防烈度下RC框架结构抗震设计与控制因素分析

为了对GB 50011—2010《建筑抗震设计规范》中RC框架结构地震倒塌风险水平进行量化统计分析，开展基于一致倒塌风险的抗震设计方法研究，依据GB 50011—2010，对18个不同层数(4、6、10层)、不同设防烈度(6~9度)的典型RC框架结构进行试设计，并依据试设计结果对各模型的抗震设计控制因素进行分析。结果表明：对于低烈度(6、7度)设防的框架结构，柱截面尺寸一般由构造要求或轴压比限值确定，最大轴压比一般出现在中柱，且重力荷载代表值所占比重很大，柱截面配筋则由最小配筋率规定和静载承重要求控制，结构构件的抗震冗余度不足；而对于中高烈度(7度(0.15g)及以上)设防的框架结构，柱截面尺寸主要由位移角限值控制，最大轴压比一般出现在边柱，且重力荷载代表值效应所占的比例随着烈度和层数的增加而显著降低，截面配筋一般由抗震承载力要求控制。

Seismic design of RC frame structures with different fortification intensities and analysis of seismic design control factors

In order to carry out quantitative statistical analysis of the seismic collapse risk level of RC frame structures designed according to the current seismic code GB 50011—2010, and to investigate the uniform-risk-based seismic design methods, a total of 18 typical RC frame structure models with different stories (4, 6, or 10 stories) and different seismic fortification intensities from 6 to 9 degree, were designed according to the current code GB 50011—2010, and the seismic design control factors of each model were analyzed in detail. The results of analysis show that: for the frame structure of low intensity (6, 7 degree), the column section size is generally determined by the construction requirements or axial compression ratio limits, the maximum axial compression ratio is generally found in the middle column with a large proportion of gravity load. The longitudinal reinforcements are controlled by the regulations of minimum reinforcement ratio or static load-bearing requirements, and the seismic redundancy of structural components is insufficient. For structures of medium-high intensity (7 degree with peak ground acceleration of 0.15g or above), the column section size is mainly controlled by the inter-story drift limit, the maximum axial compression ratio is generally found in the edge column, and the proportion of gravity load is significantly reduced with the increase of intensity and number of floors, the reinforcements of column are generally controlled by seismic bearing capacity requirements.