基于可靠度的再生混凝土梁最小配筋率研究

Reliabilitybased Study on Minimum Reinforcement Ratio of Recycled Aggregate Concrete Beams

摘要:

为考察再生混凝土强度变异性对再生混凝土梁最小配筋率的影响，以普通混凝土梁最小配筋率为参照，保持规范目标可靠指标不变，分析了再生混凝土梁受弯时的最小配筋率和受剪时的最小配箍率，并将结果与普通混凝土梁进行了对比.分析结果表明，再生混凝土梁受弯时，由于钢筋的存在，再生混凝土强度的变异性对其受弯承载力变异性的影响较小，再生混凝土梁的最小配筋率提高很小.对于再生混凝土梁受剪，当再生混凝土强度变异系数为0.2时，C30再生混凝土梁的最小配箍率为0.17%，相比较普通混凝土梁约增加32.0%.通过合理增加配筋可以保证再生混凝土梁的受弯、受剪可靠指标与普通混凝土梁一致.

Abstract:

In order to investigate the influence of recycled aggregate concrete (RAC) strength variation on the minimum reinforcement and stirrup ratios of RAC beams, this paper analyzed and compared the ratios of RAC and natural aggregate concrete (NAC) beams subjected to bending moment and shear force with the same target reliability index. The results indicate that the RAC strength variation has limited influence on the flexural capacity variation with the existence of reinforcements. As a result, the minimum reinforcement ratio almost does not increase when the beams are subjected to moment. As for the beams subjected to shear force, when the coefficient of variation of RAC tensile strength is 0.2, the minimum stirrup ratio of RAC beam is 0.17% and increases about 32.0% compared with NAC (grade C30) beam. The reliability indexes of RAC and NAC beams can be equal by increasing the reinforcement and stirrup ratios reasonably.