配置FRP的结构构件的安全储备指标及分析

Analysis of safety margin indices for structural members with FRP

由于FRP(纤维增强复合材料)的线弹性受力特性与钢材和混凝土不同,配置FRP的结构构件,如FRP加固混凝土构件、FRP筋混凝土构件、FRP-混凝土组合构件等,受力特征与传统的混凝土和钢结构构件有很大差别,因此基于传统混凝土和钢结构构件的延性概念和安全储备理论不再适用于含FRP的构件。根据结构构件在正常情况下不容许发生明显屈服的基本原则,以及理想弹塑性结构构件以承载力储备指标表达的传统结构构件安全储备方法,提出基本承载力安全储备的概念;基于结构构件在意外作用下的安全储备需要,提出附加安全储备的概念。在此基础上,采用承载能力、变形能力和变形能等指标,给出不同受力性能构件的安全储备统一表达,提出等效承载力安全储备指标。根据现行规范的设计方法,针对传统混凝土和钢结构构件,分析所建议安全储备指标的取值;进而由所建议的安全储备统一表达,对不同类型的含FRP构件的安全储备进行分析,为建立合理的配置FRP构件的设计方法提供依据。

Due to the difference between the material mechanical properties of FRP （ fiber reinforced polymer） with those of concrete and steel, the behaviors of members with FRP, such as FRP strengthened RC members, FRP bar reinforced concrete members, FRP-concrete composite members, are significantly different from traditional RC members and steel members. The concept of ductility and the corresponding safety theory and design method for traditional RC members and steel members are not suitable for members with FRP. The concepts of basic safety margin and additional safety margin are presented. The basic safety margin is based on the principle that the structural members should not yield in normal service and the method of expressing the safety margin of the traditional structural members that are approximately ideal elastic-plastic. The additional safety margin is based on the demands for offering safety under unexpected or excessive loads. The uniform safety margin for members with various mechanical behaviors is expressed in the factors of resistance capacity, deformability and deformation energy. An equivalent strength safety factor with an overall safety margin is presented. Based on the existing design codes for traditional RC members and steel members, the values of safety margin indices are proposed. Analysis of safety margin for members with FRP is conducted with the proposed unified safety factors.