人工气候下锈蚀RC框架节点抗震性能试验研究

发布时间：2018-07-12 09:49

本文选题：近海大气 + 锈蚀梁柱节点　；参考：《西安建筑科技大学》2014年硕士论文

【摘要】：钢筋混凝土框架结构是使用最广泛的结构类型之一，随着龄期的增长，耐久性损伤加剧，使得结构性能退化。因此，要准确地评估结构在地震作用下的性能，有必要考虑其耐久性损伤，这也是准确进行城市多龄期建筑易损性及灾后损失评估的基础。近海大气环境下，氯离子浓度较高，对钢筋的侵蚀严重，钢筋锈蚀成为近海大气环境下结构破坏的首要因素，本文采用人工气候加速锈蚀试验来模拟氯离子侵蚀环境下钢筋混凝土结构的加速劣化，结果表明本文所采用的加速锈蚀方案可以较好地模拟氯离子侵蚀环境下结构的劣化。分析RC框架结构时，节点区域通常采用传统的中心线模型，对于新建结构来说，这样处理偏于安全，但随着结构龄期增长，钢筋发生锈蚀，尤其是节点区域，配筋复杂，锈蚀状况相对于梁、柱构件要严重的多，此时若不考虑节点区域变形，可能使得结构分析产生误差。因此，本文设计了6个梁柱组合体，进行人工气候快速锈蚀试验研究，结果表明：节点核心区的箍筋锈蚀程度明显比梁、柱构件纵筋严重，锈蚀使得节点的延性、刚度、耗能发生退化，轴压比对锈蚀节点的影响规律与完好节点一致，即提高承载力，降低延性。并定量分析了锈蚀程度及轴压比对梁柱节点宏观力学性能的影响。在试验的基础上，得到了不同锈蚀程度下，，节点核心区域在不同受力状态下的剪力及剪切变形，通过试验数据的拟合分析得到了核心区域剪力及剪切变形随箍筋锈蚀率及轴压比的变化曲线，将基于变形和能量的退化系数引入锈蚀节点的滞回规则，确立了锈蚀节点的恢复力模型。在总结现有节点宏观模型及试验现象的基础上，提出一个节点简化宏观模型，将本文建立的恢复力模型应用于此模型中，对比分析了传统中心线模型和节点建模下，结构遭遇罕遇地震时，位移响应差异。结果表明：与完好结构相比，锈蚀RC框架结构顶点位移随着锈蚀率的增大而增大，随着锈蚀加剧底层的增大速度偏大，在锈蚀率较小时，结构的层间位移角仍能够满足限值要求；随着锈蚀率的增大，节点区域锈蚀更为严重且结构底部节点变形较大，使得结构底端层间位移增长速度明显高于顶端，结构薄弱层下移。总体来说，锈蚀会引起结构反应增大，锈蚀严重时，有必要采取节点区域建模来考虑节点变形对锈蚀RC框架整体抗震性能的影响。
[Abstract]:Reinforced concrete frame structure is one of the most widely used structural types. With the increase of age, the durability damage intensifies and the performance of the structure degenerates. Therefore, it is necessary to consider the durability damage in order to accurately evaluate the performance of structures under earthquake, which is also the basis for accurate assessment of vulnerability and post-disaster loss of urban multi-age buildings. In the offshore atmospheric environment, the chloride ion concentration is relatively high, the corrosion of steel bar is serious, the corrosion of steel bar becomes the primary factor of the structural damage in the offshore atmospheric environment. In this paper, the accelerated corrosion test in artificial climate is used to simulate the accelerated deterioration of reinforced concrete structures under chloride ion erosion. The results show that the accelerated corrosion scheme adopted in this paper can well simulate the deterioration of structures under chloride ion erosion. In the analysis of RC frame structure, the traditional centerline model is usually used in the joint area. For the newly built structure, it is safe to deal with this problem, but with the increase of the age of the structure, the reinforcement corrosion occurs, especially in the joint area, the reinforcement is complicated. The corrosion condition of column member is much more serious than that of beam. If the deformation of joint area is not considered at this time, it may make the structure analysis error. Therefore, six Liang Zhu assemblages are designed and studied in artificial climate. The results show that the corrosion degree of stirrups in the core region of joints is more serious than that of beams, and the corrosion of columns makes the ductility and stiffness of joints. The effect of axial compression ratio on energy dissipation is consistent with that of intact joints, that is, the bearing capacity is increased and the ductility is reduced. The effects of corrosion degree and axial compression ratio on the macroscopic mechanical properties of Liang Zhu joints were analyzed quantitatively. On the basis of the experiment, the shear force and shear deformation of the core region of the node under different stress conditions are obtained under different corrosion degrees. Through the fitting analysis of test data, the curves of shear force and shear deformation of core region with the corrosion rate of stirrups and axial compression ratio are obtained. The degenerative coefficients based on deformation and energy are introduced into the hysteretic rules of corroded joints. The restoring force model of corroded joints is established. On the basis of summing up the existing macroscopic model of node and experimental phenomena, a simplified macroscopic model of node is put forward, and the restoring force model established in this paper is applied to this model, and the traditional centerline model and node model are compared and analyzed. When the structure encounters rare earthquake, the displacement response is different. The results show that the vertex displacement of corroded RC frame structure increases with the increase of corrosion rate, and the increase speed of bottom layer is larger with the increase of corrosion rate, and the corrosion rate is smaller than that of intact structure. The interstory displacement angle of the structure can still meet the limit requirement. With the increase of corrosion rate, the corrosion in the joint area is more serious and the deformation of the bottom joint of the structure is larger, which makes the growth speed of the displacement between the layers at the bottom of the structure obviously higher than that at the top. The weak layer of the structure moves down. In general, the corrosion will cause the structural response to increase. When the corrosion is serious, it is necessary to take the joint region modeling to consider the effect of joint deformation on the overall seismic performance of corroded RC frame.
【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】：TU375.4;TU352.11

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