锈蚀钢筋混凝土悬臂梁变形性能有限元分析

Finite element analysis on deformation performance of corroded reinforced concrete cantilever beams

采用ABAQUS有限元软件,对按GB 50011—2010《建筑抗震设计规范》和GB 50010—2010《混凝土结构设计规范》设计的锈蚀钢筋混凝土悬臂梁进行有限元分析,研究钢筋的锈蚀率、纵向钢筋配筋特征值及剪跨比对钢筋混凝土梁变形性能的影响。研究结果表明:当钢筋的锈蚀率小于10.0%时,RC梁的变形性能受锈蚀率影响不大;当钢筋的锈蚀率超过10.0%时,由于钢筋与混凝土之间的黏结失效而发生破坏,RC梁变形能力急剧退化。对于锈蚀率小于10.0%的RC梁,其极限变形随纵向钢筋配筋特征值的增大而减小。相比纵向钢筋配筋特征值大的RC梁,剪跨比对纵向钢筋配筋特征值小的RC梁的变形性能影响更明显;对于发生黏结失效的RC梁,其极限变形受剪跨比和纵向钢筋配筋特征值影响不大。对数值计算结果进行回归分析,得到锈蚀钢筋混凝土梁屈服转角和极限塑性转角的计算公式。研究成果可为钢筋混凝土结构考虑全寿命的抗震设计和抗震性能评估提供参考。

The finite element analysis of corroded reinforced concrete( RC) cantilever beams designed according to the current ‘Code for seismic design of buildings' and the‘Code for design of concrete structures' was performed with the aid of ABAQUS software to evaluate the effects of corrosion ratio of reinforcing bars,the longitudinal reinforcement characteristic value and the shear span ratio on the deformation performance of RC beams. It is found that the corrosion ratio of reinforcing bars has little effect on the deformation performance of corroded RC beams when the corrosion ratio is less than 10%. For RC beams with corrosion ratio exceeding 10%,the beams fail due to the deterioration of bond between the concrete and the longitudinal reinforcing bars,which induces significant degradation of deformation capacity of the beams. For RC beams with corrosion ratio less than 10%,the ultimate deformation decreases with the increase of the longitudinal reinforcement characteristic value,and the shear span ratio has more pronounced effect on the deformation capacity of RC beams with low longitudinal reinforcement characteristic value than those with high longitudinal reinforcement characteristic value. Both the longitudinal reinforcement characteristic value and the shear span ratio have little effect on the ultimate deformation of RC beams failing due to the deterioration of bond between the concrete and the longitudinal reinforcing bars. Based on the regression analysis of numerical results,the expressions for the yield rotation and the ultimate plastic rotation of corroded RC beams were derived. The research results can be utilized for life-cycle oriented seismic design and seismic performance evaluation of RC structures.