摘要
针对锈蚀钢筋混凝土(RC)板柱节点的抗冲切性能,考虑混凝土内部的非均质性和钢筋锈蚀的影响,建立了三维细观尺度数值模型;在模型中将混凝土视为由骨料、砂浆和二者之间界面过渡区组成的三相复合材料;锈蚀的影响从钢筋力学性能下降、保护层混凝土开裂退化及钢筋-混凝土黏结强度降低3个方面考虑;在验证模型合理性的基础上,对锈蚀RC板柱节点的冲切破坏行为进行了模拟,分析了破坏机理,并探讨了边界条件、冲跨比和锈蚀率等因素的影响。结果表明:三维细观模型可以较好地模拟锈蚀板柱节点的抗冲切行为;同尺寸板柱节点固支时的冲切承载力、峰值位移高于简支时,而两者刚度较为接近;随着锈蚀率的提高,板底钢筋网受拉范围增大,板破坏更加严重,固支与简支板柱节点的承载力下降减缓,刚度急剧下降,峰值位移增大,同时边界条件的影响减弱;固支试件的塑性变形能力受锈蚀率的影响较小;冲跨比越大的节点刚度、承载力越低,峰值位移越大,破坏后荷载下降越快,钢筋锈蚀对冲跨比大的节点承载力、刚度、峰值位移影响较小。
A three-dimensional mesoscale numerical model was established to investigate the punching shear resistance of corroded reinforced concrete(RC)slab-column joints,taking into account the inhomogeneity inside the concrete and the influence of steel corrosion.In the model,concrete was considered as a three-phase composite material composed of aggregates,mortar,and the interface transition zone between the two.The impact of corrosion was considered from three aspects,including the decrease in mechanical properties of steel reinforcement,the cracking and degradation of protective layer concrete,and the decrease in bond strength between steel reinforcement and concrete.On the basis of verifying the rationality of the model,the punching failure behavior of corroded RC slab-column joints was simulated,the failure mechanism was analyzed,and the effects of boundary conditions,punching span ratio,and corrosion rate were explored.The results show that the three-dimensional mesoscale model can effectively simulate the punching shear behavior of corroded slab-column joints.The punching shear bearing capacity and peak displacement of fixed supported slab-column joints of the same size are higher than those of simply supported ones,while the stiffness is closed.As the corrosion rate increases,the tensile range of the steel mesh at the bottom of the plate increases,and the damage to the plate becomes more severe.The decrease in bearing capacity of the fixed and simply supported plate column joints slows down,the stiffness sharply decreases,the peak displacement increases,and the influence of boundary conditions weakens.The plastic deformation ability of the fixed support specimen is less affected by the corrosion rate.The higher the impact span ratio,the lower the stiffness and bearing capacity of the joint,the greater the peak displacement,and the faster the load decreases after failure.The corrosion of steel reinforcement has a smaller impact on the bearing capacity,stiffness,and peak displacement of joints with a higher impact
作者
石磊
张仁波
王锺谋
金浏
杜修力
SHI Lei;ZHANG Renbo;WANG Zhongmou;JIN Liu;DU Xiuli(China Building Technique Group Co.,Ltd.,Beijing 100013,China;Key Laboratory of Urban Security and Disaster Engineering of Ministry of Education,Beijing University of Technology,Beijing 100124,China)
出处
《建筑科学与工程学报》
CAS
北大核心
2023年第4期87-96,共10页
Journal of Architecture and Civil Engineering
基金
国家重点研发计划项目(2019YFC1511003)
国家自然科学基金项目(51822801)。
关键词
钢筋锈蚀
板柱节点
冲切破坏
数值模拟
steel reinforcement corrosion
slab-column joint
punching shear failure
numerical simulation
