钢筋混凝土框架结构实现“强柱弱梁”初步研究

发布时间：2018-03-17 13:33

本文选题：强柱弱梁　切入点：强柱弱梁系数限值　出处：《中国地震局工程力学研究所》2014年硕士论文　论文类型：学位论文

【摘要】：钢筋混凝土框架结构在实际大地震中大多没有实现规范所预期的“强柱弱梁”破坏模式，更多的是出现了柱端先出现塑性铰的情况，这种破坏模式容易造成结构的整层破坏，甚至整体倒塌，从而造成大量人员伤亡及重大财产损失。为解决这一严重问题，通过对“强柱弱梁”这一概念进行深入分析，采用不同的参数来表征不同层次的含义，提出了强柱弱梁系数这一新的参数，来表征柱和梁的相对屈服情况，通过对强柱弱梁系数进行限值确保结构在地震作用下实现“强柱弱梁”。将结构由“强柱弱梁”破坏模式转换为“强梁弱柱”破坏模式的临界强柱弱梁系数定义为强柱弱梁系数限值，并采用有限元软件ABAQUS对强柱弱梁系数限值进行了计算、分析和验证。本文研究的主要内容和结论如下： 1、总结钢筋混凝土框架结构的震害特点，提出强柱弱梁系数与强柱弱梁系数限值，并分别给出明确的定义和意义。选取最简单的钢筋混凝土框架结构模型，采用有限元软件ABAQUS对强柱弱梁系数和强柱弱梁系数限值的求算方法进行了示范。 2、通过有限元软件ABAQUS进行大量的数值模拟，讨论强柱弱梁系数限值在不同条件下的变化规律。研究发现：随轴压比的提高，强柱弱梁系数限值的提高先平稳后快速；同一结构在双向地震动输入时求得的强柱弱梁系数限值小于单向地震动输入时求得的强柱弱梁系数限值；同一地震动调整不同的峰值加速度对于强柱弱梁系数限值的影响不大；不同地震动调整至相同峰值加速度对于强柱弱梁系数限值的影响在轴压比较小时不大，在轴压比较大时影响较大。通过将强柱弱梁系数限值与规范中的柱端弯矩增大系数进行比较，，考察规范对于“强柱弱梁”问题的体现是否合理，经过分析可知，仅就柱梁的相对强弱来看，现行规范并不能完全保证结构在地震动作用下实现“强柱弱梁”。 3、通过设计一个5层的钢筋混凝土框架结构并进行数值模拟，选取两条有代表性的地震动，考察了强柱弱梁系数和强柱弱梁系数限值规律的正确性。同时，分析了符合规范要求的结构在某些地震动作用下可能的破坏模式，指出在某些情况下，结构虽有先形成柱端塑性铰的危险，可是由于构件本身的强度较大，无论是柱端还是梁端可能都不形成塑性铰。
[Abstract]:Most reinforced concrete frame structures do not realize the failure mode of "strong column and weak beam" as expected in the code in the actual earthquake, and more often the plastic hinge appears at the end of the column, which can easily cause the whole story failure of the structure. Even the whole collapse, resulting in a large number of casualties and heavy property losses. In order to solve this serious problem, the concept of "strong column and weak beam" is deeply analyzed, different parameters are used to represent the meaning of different levels, and a new parameter, the coefficient of strong column and weak beam, is put forward. To characterize the relative yield of columns and beams, By limiting the coefficient of strong column and weak beam to ensure that the structure can realize "strong column and weak beam" under earthquake action, the critical coefficient of strong column and weak beam is defined as the critical mode of structural failure from "strong column and weak beam" to "strong beam and weak column". The limit value of the coefficient of strong column and weak beam, The finite element software ABAQUS is used to calculate, analyze and verify the limit value of the coefficient of strong column and weak beam. The main contents and conclusions of this paper are as follows:. 1. The earthquake damage characteristics of reinforced concrete frame structures are summarized, and the limit values of strong column weak beam coefficient and strong column weak beam coefficient are put forward, and the clear definition and significance are given respectively. The simplest reinforced concrete frame structure model is selected. The finite element software ABAQUS is used to demonstrate the calculation method of the limit value of the coefficient of weak beam of strong column and the coefficient of weak beam of strong column. 2. The finite element software ABAQUS is used to carry out a lot of numerical simulation to discuss the variation law of the limit value of the coefficient of strong column and weak beam under different conditions. It is found that with the increase of axial compression ratio, the increase of the limit value of the coefficient of strong column and weak beam is first stable and then rapid; The limit value of the coefficient of the strong column and the weak beam of the same structure is smaller than the limit value of the coefficient of the strong column and the weak beam when the input of the unidirectional ground motion is obtained, and the influence of the different peak acceleration of the same ground motion on the limit value of the coefficient of the strong column and the weak beam is not significant. The influence of different ground motion adjustment to the same peak acceleration on the limit value of the coefficient of strong column and weak beam is small when the axial compression ratio is small. By comparing the limit value of the coefficient of strong column and weak beam with the increasing coefficient of bending moment at the end of column in the code, we can find out whether the code is reasonable for the problem of "strong column and weak beam". According to the relative strength of column beam, the current code can not completely guarantee that the structure can realize "strong column and weak beam" under the action of ground motion. 3. Through the design and numerical simulation of a five-story reinforced concrete frame structure, two representative ground motions are selected to investigate the validity of the limit law of the coefficient of strong column and weak beam and the coefficient of strong column and weak beam. The possible failure modes of structures which meet the requirements of the code under some ground motions are analyzed. It is pointed out that, in some cases, the structure has the danger of forming plastic hinge at the end of the column first, but the strength of the member itself is large. Plastic hinges may not be formed either at the end of the column or at the end of the beam.
【学位授予单位】：中国地震局工程力学研究所
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU375.4

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