偏心受拉转换梁的“强剪弱弯”设计可靠度分析

为实现钢筋混凝土斜柱式或斜撑式转换结构构件"强剪弱弯"的概念设计,保证斜柱或斜撑与框支柱之间的转换梁在偏心受拉状态下的"强剪弱弯"设计,采用可靠度的Monte Carlo分析方法,把转换梁看作由偏心受拉破坏与受剪破坏组成的串联体系,对按现行建筑结构规范设计的钢筋混凝土转换梁在偏心受拉状态下的"强剪弱弯"抗震可靠性进行了分析,研究了不同荷载比值(地震作用与自重荷载比值)、不同截面、材料强度等级和不同配筋率对偏心受拉梁"强剪弱弯"可靠度的影响。在此基础上,针对一、二级抗震等级偏心受拉转换梁"强剪弱弯"的设计,对目标可靠指标的剪切增强系数进行了校核,为合理地确定剪切增强系数提供参考。

Reliability analysis of transfer beams designed according to "strong shear weak bending" and under eccentric tension

In order to realize the design concept of "strong shear weak bending" for the transfer members of the reinforced concrete transfer structure with inclined column or haunching brace,and ensure "strong shear weak bending" for the transfer beam under eccentric tension and between the inclined column or haunching brace and the transfer column,using Monte Carlo method for reliability analysis and taking the transfer beams as a connected system of eccentric tensile failure and shear failure,the "strong shear weak bending" seismic reliability analysis is carried out for reinforced concrete transfer beams which are under eccentric tension and designed according to the current building code.The influence of different load ratios such as the ratio of seismic action and gravity load,different sections,different grades of material and different reinforcement ratios on the reliability of beams under eccentric tension are discussed.For the transfer beams under eccentric tension and designed according to "strong shear weak bending" rule based on first and second seismic grades,the target reliability index for shear enhancement factor is checked to provide references for reasonable analysis.