高强钢筋聚丙烯纤维混凝土梁正常使用极限状态可靠度分析

Reliability analysis at serviceability limit state for polypropylene fiber concrete beams reinforced with high strength steel bars

对6根矩形截面混凝土梁进行了受弯破坏试验。考虑到应用HRB500级钢筋作为受力主筋，可能会导致构件出现过宽裂缝而不能满足结构适用性和耐久性的要求，其中4根试验梁掺入了定量聚丙烯纤维进行对比试验研究。在试验基础上，对高强钢筋混凝土梁进行了基于横向裂缝宽度的正常使用极限状态可靠度对比分析。研究结果表明：配置HRB500级钢筋的混凝土梁基于裂缝宽度的正常使用极限状态下的可靠度指标相对偏低，而掺人聚丙烯后的混凝土梁的可靠度指标有所提高。两者基于裂缝宽度的正常使用极限状态的可靠度指标均符合可靠度指标范围0-1．5。

In order to investigate the bending behavior of concrete beam reinforced with HRB500 steel bars, tests on 6 rectangular section fiexural members were carried out.However, such concrete beams, applying higher tensile steel as reinforcement,may appear oversized cracks which cannot satisfy the requirement for applicability and durability.Therefore,4 flexural members added polypropylene fibers are designed to compared in aspects of crack width.Therefore, the reliability at serviceability limit state for concrete beams reinforced with HRBS00 was analyzed.The analysis results indicate that reliability indexs based on crack width at serviceability limit state of the concrete beams with HRBS00 is low;and reliability index of concrete beams reinforced with HRB500 is promoted by polypropylene fibers.In general,reliability indexs of these two kind of members based on crack width at serviceability limit state both meet the reliability index range of 0 to 1.5.