将JC法与Monte Carlo随机抽样方法结合,对ACI 440.1R-03技术报告(简称ACI指南)和ISIS设计手册3(简称ISIS指南)中正截面受弯承载力的设计条款进行了可靠度评估.研究表明,对于两指南,混凝土强度和FRP筋特性分别是影响混凝土压碎破坏模式和FRP筋拉断破坏模式下抗力均值及其方差最重要的影响因素.可靠度水平在两种不同破坏模式之间将会发生跳跃,但在各自破坏模式状态下,可靠度水平基本不随FRP筋相对配筋率的变化而变化.对于ACI指南,不同FRP筋对应的可靠度水平相差不大,均偏于保守,而对于ISIS指南,相差悬殊的FRP筋强度折减系数也导致可靠度水平相差较大,CFRP筋拉断破坏模式对应的可靠度指标明显低于混凝土压碎破坏情况,无论何种破坏模式,配置GFRP筋情况下的可靠度水平过高.
Combined with the Monte Carlo random sampling process, the JC method was applied to carry out a reliability evaluation of design provisions of flexural capacity in technical report ACI 440. 1R - 03 ( called ACI guideline) and ISIS design manual No. 3 (called ISIS guideline). The evaluation indicates that, for both guidelines, concrete strength and FRP strength are the most dominating influencing factors for the failure modes of concrete crushing and FRP rupture, respectively. Reliability level varies dramatically when failure mode changes. However, the reliability indexes appear to be irrelevant to FRP reinforcement ratio within either mode. For ACI guideline, the reliability levels corresponding to different types of FRP rods show little differences and they are rather conservative to some extent. But, for ISIS guideline, distinct differences in the strength reduction factors of different types of FRP rods result in sharp differences in reliability level. The reliability indexes corresponding to the failure mode of CFRP rupture are much lower than those corresponding to concrete crushing mode. As to concrete reinforced GFRP rebars, the reliability levels corresponding to either mode are over conservative.