既有砌体结构安全性评估的分项系数研究

Study on the partial safety assessment factors of existing masonry structures

既有结构安全性评估是基于已知的结构信息,对结构是否能够承受预期荷载做出判断的过程;基于既有砌体结构抗力的材料性能、几何特征以及永久作用为确定量的基本假设,给出了适用于既有砌体结构安全性评估的极限状态表达式及其分项系数和安全性分级原则。结果表明,A类、B类和C类既有砌体结构安全性评估的分项系数可取值为:抗力分项系数γR取1.6(对应的材料分项系数γf为1.2);永久作用分项系数γG取1.0;对于可变作用分项系数γQ,A类构件取1.3,B类构件取1.4,C类构件取1.5。对于重要性系数γ0,可与《工程结构可靠性设计统一标准》(GB 50153—2008)保持一致;对于安全性分级标准,可与《民用建筑可靠性鉴定标准》(GB 50292—2015)保持一致。

The safety assessment of an existing structure determines whether the structure can survive the predicted load based on available structural information.According to the basic assumption that the material properties,geometric characteristics and permanent action are certain,the ultimate state expression,partial factors and safety grading principles of safety assessment of existing masonry structures were proposed.The results show that the partial safety assessment factors of existing masonry structures of classes A,B and C can be as follows.The partial resistance factor can be 1.6,equivalent to the partial material factor of 1.2.The partial permanent action factor can be 1.0.The variable action partial factors can be 1.3,1.4 and 1.5 for masonry structural members of classes A,B and C respectively.The important factors shall comply with Unified standard for reliability design of engineering structures(GB 50153—2008).The safety classification principles shall comply with Standard for appraisal of reliability of civil buildings(GB 50292—2015).