锈蚀钢筋混凝土梁抗弯刚度评估方法研究

为合理评估锈蚀钢筋混凝土梁的变形能力,对影响锈蚀混凝土梁抗弯刚度退化的因素进行系统分析,明确锈蚀引起粘结力退化使裂缝间受拉钢筋应变趋于均匀和钢筋应变与混凝土应变不协调是影响锈蚀混凝土梁抗弯刚度计算模型建立的关键因素;抛弃传统的平截面假定,采用刚度解析法对粘结力退化后构件截面刚度进行了理论分析,引进综合应变系数考虑裂缝间钢筋应变趋于均匀和应变不协调的影响,建立了锈蚀钢筋混凝土梁抗弯刚度的计算模型;通过有限元数值分析,确定了综合应变系数与粘结强度退化系数的关系;经试验验证,模型计算结果与试验结果吻合较好。

STUDY ON EVALUATION METHOD OF FLEXURAL STIFFNESS OF CORRODED R.C.BEAMS

In order to evaluate deformation capacity of corroded R.C.beams,factors affecting flexural stiffness of corroded R.C.beams are investigated,and a conclusion is reached that key factors affecting the establishment of calculation model are steel strain between cracks tending to uniformly distributed and steel strain lagging behind concrete strain for bond degrading due to steel corrosion.Throwing off conventional plane hypothesis,the section stiffness of flexural members with deteriorated bond strength is analyzed by means of stiffness analytic method.A comprehensive strain coefficient is adopted to reflect effects of both steel strain tending to uniformly distributed and lagging behind,and a calculation model of flexural stiffness of R.C.beams with corroded bars is established.By means of finite element analysis,the relationship between comprehensive strain coefficient and reduced coefficient of bond strength is built.The formula is used to analyze flexural stiffness of some tested members,and calculated results coincide with test results well.