【作者】 王娜；

【导师】 杨树标；

【作者基本信息】 河北工程大学 ， 结构工程， 2011， 硕士

【摘要】 近年来,随着框架结构在各类建筑中广泛应用,框架结构的抗震性能越来越引起重视。我国规范对框架结构的设计要求为“强柱弱梁”,即结构进入塑性阶段时,塑性铰出现在梁端,屈服后结构具有较好的延性,保证结构不会倒塌,同时结构的塑性变形也可耗散地震能量。大量震后资料显示,框架结构对地震的影响反应没有达到预期的“强柱弱梁”要求。震后大部分框架柱破坏严重,轻者结构倾斜,重者形成层间侧移机制,导致整体倒塌,框架梁的破坏则明显较轻。本文将针对该问题进行研究探讨。为了研究结构的破坏机制,本文对结构采用Pushover分析,首先介绍了Pushover分析的基本原理和过程及SAP2000有限元软件,该软件功能强大,可以充分满足本文研究目的的需要。框架结构不能满足“强柱弱梁”要求的原因有:(1)梁端实际超筋;(2)现浇楼板对梁的加强;(3)柱的最小配筋率和最小配箍率偏小;(4)柱轴压比偏大。但最主要的原因还是目前对框架柱强度的要求不够。针对该问题,本文以实际框架结构工程为例,严格按照我国规范进行设计,采用SAP2000有限元软件对其进行Pushover分析,得到结构的塑性发展过程。之后对结构从四个方面进行改进:第一,增大梁柱混凝土强度级差;第二,增大柱端弯矩增大系数;第三,增大梁柱配筋级差;第四,增大柱截面面积。然后分别进行Pushover分析,观察塑性发展过程,发现除增大梁柱混凝土强度级差外其余三种方法都能改进结构破坏机制,实现强柱弱梁。此外,本文还对几种方法的经济性进行了比较,发现增大梁柱配筋级差增加的成本最少,增大柱截面面积增加的成本最多。并且增大梁柱配筋级差可在现有规范下使用,是最经济实用的方法。最后,针对框架—剪力墙结构震后破坏较轻,剪力墙虽然有部分开裂或倒塌,但主体框架无严重损坏的现象,将结构改进为框架—剪力墙结构,并对其进行Pushover分析,观察塑性发展过程,对其抗震性能进行分析。分析结果表明框架—剪力墙结构的抗震性能良好,破坏机制也比较合理,符合设计期望。更多还原

【Abstract】 The frame structure was widely used in various buildings in recent years. And the experts pay more and more attention to the seismic performance of frame structures. Chinese standard’s design requirements for the framework is“strong column and weak beam”, that is when the structure enters the plastic state, plastic hinges appear at the ends of beams, and have good ductility after post-yield. The structure will not collapse, and plastic deformation of structure can dissipate seismic energy.The data after the earthquake shows that the frame structures’response to the earthquake did not reach the expected requirement which is“strong column and weak beam”. Most of the frame columns were damaged seriously. Some form plastic hinges at column ends and slope. Some occur interlayer lateral displacement, then lead to an overall collapse finally. While the frame beams’damage were lighter significantly.In order to study on structure’s failure mechanism, this paper adopts Pushover analysis, introduces basic principle and process of Pushover analysis and SAP2000 finite element software. SAP2000 is powerful, that can meet requirement of the paper’s research purpose.The reasons for the frame can not reach the strong column and weak beam requirement are :(1)over bar of the beam ends;(2)strengthening to the beams of cast-in-place floor ;(3)the minimum reinforcement ratio and the minimal stirrup ratio of the columns are small;(4)axial compression ratio of columns is large relatively. But the main reason is the requirement to the columns is not enough currently. The chapter three of this essay takes a actual building as an example, designs the structure according to our specifications strictly. Then it makes Pushover analysis by SAP2000 finite element analysis software, and gets the plastic development of the structure. Improve the structure in four aspects: The first , augmenting concrete strength grade of columns.; The second , increasing the moment magnifying factors at column ends; The third , enlarging steel strength grade of columns; The fourth,. This paper makes Pushover analysis and observes the plastic development of the structures. The result shows the first three methods are all effective, the fourth method is not very effective. Besides, the paper compared that methods on economic. Enlarging steel strength grade of columns is the cheapest, while increasing the area of column section is the most expensive. Enlarging steel strength grade of columns can be used under norms, and is economic and practical.Finally, because frame - shear wall structures’damage is lighter after earthquake, the main frame do not have serious damage, while some of the shear walls have cracks or collapses. The original structure was modified to frame - shear wall structure in the chapter four of this essay. The chapter four makes Pushover analysis on the frame - shear wall structure, observes the plastic development of the structure and studies on its seismic performance. The conclusion shows that the seismic performance of frame - shear wall is good, failure mechanism is reasonable, and can meet the design expectations.更多还原