再生混凝土梁抗弯承载力计算适用性研究

APPLICABILITY RESEARCH ON BENDING LIMIT CARRYING CAPACITY OF RECYCLED CONCRETE BEAMS

通过对3组15个不同再生粗骨料取代率、配筋率的梁在集中荷载作用下进行抗弯性能试验研究,分析再生骨料取代率对再生混凝土梁满足平截面假定、挠度变形、裂缝宽度以及极限承载力等方面的影响,同时对现行GB 50010—2002《混凝土结构设计规范》中混凝土正截面极限承载力计算公式计算再生混凝土梁极限承载力的适用性进行探讨。研究结果表明:在同级荷载作用下,再生混凝土梁较天然混凝土梁裂缝开展快、裂缝最大宽度大、抗弯刚度降低快;在逐级加载过程中无论再生粗骨料取代率大小,再生混凝土梁正截面混凝土应变变化仍满足平截面假定要求;按现行规范公式计算再生混凝土梁的极限承载力是可行的,但缺少相应的再生骨料取代率影响因子,针对此问题提出建议公式与调整系数,并通过数据分析证明其满足基本要求。

Based on bending performance experiment of three groups beams with fifteen test components,whose recycled coarse aggregate replacement rate were different,it was the article analyzed the effect of recycled aggregate replacement ratio on RAC beams meeting the linear plane assumption,deflection,crack width and limit carrying capacity.Meantime the applicability of recycled concrete beams bending limit carrying capacity by ＂Code for Design of Concrete Structures＂（GB 50010—2002） was discussed.The research indicated that under the same loads,the appearance of crack on the recycled concrete beams was previous while the width of crack was larger on recycled concrete beams and recycled concrete beams degraded rapidly in stiffness as well.The average strain measured on cross-section could meet the requirement of the plane section assumption.The computational results of recycled concrete beams bending limit carrying capacity by Code for Design of Concrete Structures were feasible,but the formula of GB 50010—2002 was not comprehensive.It was introduced a kind of suggested formula and adjustment coefficient,which could help to solve related calculation problem and was proved to be effective.