基于可靠度分析的再生混凝土材料分项系数

RELIABILITY-BASED STUDY ON PARTIAL COEFFICIENT OF RECYCLED AGGREGATE CONCRETE

为研究再生混凝土强度变异性对再生混凝土材料分项系数的定量影响,以普通混凝土受弯梁为参照,保持目标可靠指标不变,分别设定再生混凝土的强度均值,标准值和设计值与普通混凝土相同,分析了三种情况下的再生混凝土的材料分项系数和强度设计值的取值。分析结果表明,上述三种情况下,当再生混凝土的强度变异系数大于普通混凝土强度变异系数时,为保证再生混凝土梁受弯时的可靠指标达到现行规范目标可靠指标,其所需配筋率依次降低,所需再生混凝土配合比设计强度依次增加。当再生混凝土的强度变异系数小于等于0.15时,取均值相同时的C30、C40再生混凝土的材料分项系数为1.41和1.35,标准值相同时为1.43和1.41,设计值相同时为1.45和1.41,都可以保证再生混凝土梁的受弯可靠指标达到现行规范的要求。

In order to investigate the influence of recycled aggregate concrete （RAC） strength variation on RAC partial coefficients, using normal aggregate concrete （NAC） beams as references and keeping the same target reliability index, this paper analyzed RAC partial coefficients and RAC design strengths in three cases including RAC mean strength, standard strength and design strength, being the same as those of NAC, respectively. The results indicate that： when the reliability indexes of RAC beams reach the target reliability index under the same coefficient of variation （larger than that of NAC） of strength, the required reinforcement ratio is decreased while the required strength of concrete is increased as the case changes from same mean strength to same standard strength then to same design strength. From partial coefficient perspective, when the coefficient of variation of concrete is less than or equal to 0.15, the C30 and C40 RAC partial coefficients will be 1.41 and 1.35 for the case of same mean strength, 1.43 and 1.41 for the case of same standard strength, and 1.45 and 1.41 for the case of same design strength; and ensuring all of the RAC beams subjected to bending moment reach the target reliability.