既有与改进节点形式的钢框架结构抗震性能评估

发布时间：2018-04-09 08:12

本文选题：钢框架　切入点：钢材锈蚀　出处：《西安建筑科技大学》2014年博士论文

【摘要】：通常评估结构抗震性能仅考虑结构变形,而未考虑结构的累积损伤,对于“强柱弱梁”设计的框架结构,框架梁为结构在遭遇较大地震作用下主要的耗能构件。然而,框架梁的耗能能力并未如预期所愿,国内外历次震害资料显示,钢结构节点区在地震作用下易发生脆性断裂,进而导致结构破坏,钢结构良好的耗能能力并未得到充分发挥,且钢材耐锈蚀性较差,在锈蚀环境下易发生锈蚀现象,而目前国内外对钢构件或结构评估时,均未考虑钢材锈蚀对其力学性能的影响。本文研究既有钢结构构件与结构在服役过程中因钢材锈蚀导致其抗震性能的衰减规律,提出考虑变形与耗能的双参数地震损伤模型,进而基于不同损伤指标对不同龄期钢框架结构进行地震易损性评估,并提出提高节点耗能能力的改进措施。本文主要开展以下几个方面的研究工作:(1)通过对无涂层的Q235B梁柱焊接连接的框架节点模拟近海大气环境作用进行盐雾室内加速锈蚀试验与拟静力破坏试验,给出钢框架节点在不同锈蚀率、不同加载制度下的塑性发展与破坏特征,给出其承载能力、变形能力与耗能能力指标随锈蚀率的衰变关系,填补国内对于锈蚀钢结构构件抗震性能研究的空白。(2)提出适用于钢结构框架节点的损伤模型,并考虑锈蚀对节点抗震性能的影响,提出适用于钢结构框架节点在不同锈蚀程度下考虑变形与耗能的双参数时变损伤模型。(3)考虑钢材锈蚀对构件与结构承载力、变形与耗能的影响,采用不同损伤指标评价结构抗震性能,建立钢框架多龄期易损性模型,给出考虑时间参数的易损性曲面。(4)提出等强节点,即在几乎不改变节点刚度与承载力的同时实现塑性铰外移,通过提高节点变形与耗能能力提高结构抗震性能。
[Abstract]:In general, the seismic behavior of a structure is evaluated only by considering the deformation of the structure, but not by the cumulative damage of the structure. For the frame structure designed by "strong column and weak beam", the frame beam is the main energy dissipation member of the structure under the action of large earthquake.However, the energy dissipation capacity of the frame beam is not as expected. The previous earthquake damage data at home and abroad show that brittle fracture occurs easily in the joint zone of steel structure under earthquake, which leads to structural failure.The good energy dissipation capacity of steel structure has not been fully developed, and the corrosion resistance of steel is poor, and it is easy to rust in the corrosion environment. But at present, when the steel members or structures are evaluated at home and abroad,The effect of steel corrosion on mechanical properties was not considered.In this paper, the attenuation law of seismic performance of existing steel structure members and structures caused by steel corrosion during service is studied, and a two-parameter seismic damage model considering deformation and energy dissipation is proposed.Furthermore, based on the different damage indexes, the seismic vulnerability of steel frame structures of different ages is evaluated, and the improvement measures to improve the energy dissipation capacity of joints are put forward.In this paper, the following aspects of research work: 1) accelerated corrosion test and pseudostatic failure test in salt fog chamber are carried out by simulating the effect of offshore atmospheric environment on the frame joints welded by uncoated Q235B Liang Zhu.The plastic development and failure characteristics of steel frame joints under different corrosion rates and different loading conditions are given. The decay relationship between the load-carrying capacity, deformation capacity and energy dissipation capacity with corrosion rate is given.In order to fill the blank in the study of seismic behavior of corroded steel structure members, a damage model suitable for steel frame joints is proposed, and the effect of corrosion on the seismic behavior of joints is considered.A two-parameter time-varying damage model for steel frame joints considering deformation and energy dissipation under different corrosion degrees is proposed. The effects of steel corrosion on the bearing capacity, deformation and energy dissipation of steel members and structures are considered.Using different damage indexes to evaluate the seismic performance of the structure, the multi-age vulnerability model of steel frame is established, and the vulnerability surface of steel frame considering time parameter is given.That is to say, the plastic hinge can be shifted from outside without changing the stiffness and bearing capacity of the joints, and the seismic performance of the structure can be improved by increasing the deformation and energy dissipation capacity of the joints.
【学位授予单位】：西安建筑科技大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TU352.11;TU391

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