锈蚀钢筋混凝土梁抗弯承载力计算方法

目前对锈蚀钢筋混凝土梁抗弯承载力的研究主要考虑锈蚀程度的影响,忽视了构件本身参数不同对承载力退化的影响,导致不同学者提出的锈蚀钢筋与混凝土的协同工作系数差异较大。为合理评估既有锈蚀钢筋混凝土梁的剩余承载力,首先对锈后无黏结钢筋混凝土受弯构件进行模拟试验与有限元分析,系统分析严重锈蚀混凝土构件钢筋应力水平的主要影响因素,发现截面配筋指标可综合反映混凝土强度和截面配筋率对受拉钢筋应力水平的影响,并确定基于截面配筋指标的锈后无黏结混凝土梁受拉钢筋强度利用系数;对一般锈蚀钢筋混凝土梁抗弯承载力的退化机理进行深入分析,综合考虑钢筋锈蚀程度和截面配筋指标的影响,建立一般锈蚀混凝土梁钢筋强度利用系数计算公式;提出概念明确、通用性强的锈蚀钢筋混凝土梁抗弯承载力计算方法;与大量的试验结果进行对比验证,计算方法的吻合性较好。

Calculation method for flexural capacity of corroded RC beams

The degree of corrosion of reinforced bars is the main factor of concern in current studies on flexural capacity of corroded RC beams,whereas the influences of other parameters of test members are often ignored,which leads to great differences between the cooperation coefficients of corroded bars with concrete given by different scholars.In order to evaluate the residual capacity of existing corroded RC beams,simulation test and finite element method were used to study the behavior of unbonded RC beams due to heavy corrosion.Factors which influence bar stress in heavily corroded RC members were investigated in detail.Results indicate that reinforcement index can reflect the effects of both concrete strength and reinforcement ratio on steel stress.Depending on reinforcement index,a formula for utilization coefficient of steel strength of unbonded RC beams was proposed.Degrading mechanism of load capacity for ordinary corroded RC beams was analyzed,and a calculation method for flexural capacity,conceptually explicit and widely applicable,was proposed,taking consideration of both corrosion degree and reinforcement index.The method was used to analyze the flexural capacity of a large number of tested members,and the agreement between calculated results and the experimental results was reasonable.