人工气候环境下锈蚀RC框架梁抗震性能试验研究

发布时间：2018-05-26 08:31

本文选题：人工气候环境 + 钢筋锈蚀　；参考：《西安建筑科技大学》2014年硕士论文

【摘要】：随着人工气候环境加速腐蚀方法在混凝土结构耐久性领域中的逐步推广，本研究采用人工气候环境模拟技术实现RC框架梁的加速腐蚀，，分析了不同锈蚀程度下RC框架梁的抗震性能退化规律，建立了锈蚀RC框架梁的恢复力模型，对锈蚀RC框架梁的抗震性能进行了数值建模分析。成果可为考虑环境作用的多龄期RC框架结构的抗震性能研究提供理论指导。本文的主要研究工作和成果如下：（1）设计不同锈蚀程度、不同配箍率RC框架梁试件，进行锈蚀RC框架梁试件拟静力加载试验。采用人工气候环境加速腐蚀，基于裂缝宽度控制试件的加速腐蚀，于拟静力试验后，对塑性铰区混凝土破碎，测得箍筋与纵筋的实际锈蚀率。处理试验数据，得到RC框架梁的滞回曲线、骨架曲线、刚度退化、强度退化及耗能能力退化曲线。（2）分析锈蚀率对RC框架梁抗震性能退化规律的影响。力学性能方面：随着钢筋锈蚀程度的增加，锈蚀RC框架梁的承载力、刚度、延性、塑性转角、变形恢复能力和滞回耗能逐渐降低；配箍率对锈蚀RC梁恢复力特性的影响与未锈蚀梁相似。破坏形态方面：随着钢筋锈蚀加剧，RC框架梁由弯曲破坏为主的弯剪破坏模式，逐步转变为延性更差、剪切变形更明显的脆性破坏；前者是因为纵向钢筋屈曲逐渐失去承载力，核心混凝土压碎引起的；后者是因为斜裂缝过宽或在截面范围内出现贯通斜裂缝引起的，混凝土抗剪承载力严重削弱，塑性铰区剪切变形明显增大。（3）建立锈蚀RC框架梁的恢复力模型。基于带有负刚度段的三折线骨架曲线，依据本文试验数据回归分析得到锈蚀框架梁骨架曲线特征点计算公式。基于滞回耗能的循环退化指数，本文所建立的滞回模型综合考虑了构件的捏拢效应、强度退化、卸载刚度退化、硬化刚度退化和再加载刚度加速退化。计算滞回曲线与试验滞回曲线对比表明：所建立恢复力模型能够较好的描述锈蚀RC框架梁的滞回特性。（4）基于OpenSees，将本课题组的锈蚀箍筋约束混凝土本构模型添加于OpenSees源程序中，对锈蚀RC框架梁进行低周反复荷载作用下的抗震性能分析。将数值模拟结果与本人及他人试验结果进行对比表明：此种考虑锈蚀作用的RC框架梁的有限元数值建模方法具有较好的适用性。
[Abstract]:With the gradual popularization of accelerated corrosion method in the field of concrete structure durability, the accelerated corrosion of RC frame beam is realized by artificial climate environment simulation technology. The degradation law of seismic behavior of RC frame beam with different corrosion degree is analyzed, and the restoring force model of corroded RC frame beam is established. The seismic behavior of corroded RC frame beam is modeled and analyzed numerically. The results can provide theoretical guidance for the study of seismic behavior of multi-age RC frame structures considering environmental effects. The main research work and results are as follows: 1) the specimens of RC frame beams with different corrosion degrees and different hoop ratios were designed and subjected to pseudo-static loading tests of corroded RC frame beams. Based on the accelerated corrosion of specimens controlled by crack width, the concrete in plastic hinge region was broken and the actual corrosion rate of stirrups and longitudinal bars was measured after pseudostatic test. The hysteresis curve, skeleton curve, stiffness degradation, strength degradation and energy dissipation degradation curve of RC frame beam are obtained by processing the test data. 2) the effect of corrosion rate on seismic degradation of RC frame beam is analyzed. Mechanical properties: with the increase of steel corrosion degree, the bearing capacity, stiffness, ductility, plastic rotation angle, deformation recovery ability and hysteretic energy consumption of corroded RC frame beams gradually decreased. The effect of hoop ratio on the restoring force characteristics of corroded RC beams is similar to that of non-corroded RC beams. The failure mode of RC frame beam is gradually changed into a brittle failure with worse ductility and more obvious shear deformation, which is caused by the buckling of longitudinal steel bar, which is caused by the gradual loss of the bearing capacity of the RC frame beam due to the bending failure of the RC frame beam. The latter is caused by too wide slant cracks or through oblique cracks in the range of cross section. The shear bearing capacity of concrete is seriously weakened and the shear deformation in plastic hinge region is obviously increased. The restoring force model of corroded RC frame beam is established. Based on the three-fold skeleton curve with negative stiffness and the regression analysis of the experimental data in this paper, the formula for calculating the characteristic points of the skeleton curve of corroded frame beam is obtained. Based on the cyclic degeneracy index of hysteretic energy, the hysteretic model proposed in this paper takes into account the pinch effect, strength degradation, unloading stiffness degradation, hardening stiffness degradation and accelerated reloading stiffness degradation. The comparison between the calculated hysteretic curve and the experimental hysteretic curve shows that the established restoring force model can well describe the hysteretic characteristics of corroded RC frame beams. 4) based on OpenSees, the constitutive model of corroded stirrups confined concrete is added to the OpenSees source code to analyze the seismic behavior of corroded RC frame beams under low cyclic loading. The numerical simulation results are compared with the experimental results of myself and others. The results show that this finite element numerical modeling method for RC frame beams considering corrosion is applicable.
【学位授予单位】：西安建筑科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU375;TU352.11

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