【作者】 石宏彬；

【导师】 孙景江；

【作者基本信息】 中国地震局工程力学研究所 ， 防灾减灾工程及防护工程， 2012， 博士

【摘要】 结构抗震设计的基本原则之一是保证“强柱弱梁”，期望在强烈地震中，梁先于柱破坏，消耗地震能量，避免结构倒塌。然而实际震害表明，RC框架结构并未实现预期的“强柱弱梁”破坏模式，更多的表现为“强梁弱柱”破坏。研究表明，影响形成“强柱弱梁”的因素较多，主要可归结为楼板的作用、填充墙的影响、梁承载力超强以及钢筋超配等。另外，设计中将填充墙作为非结构构件考虑，不参与结构抗震计算，然而大量震害实例表明，其对结构抗震性能有较大影响。本文针对填充墙影响和“强梁弱柱”形成机制问题进行了研究，主要工作和成果如下：1.表明填充墙是结构耗能的主体并改变了框架结构的内力分布。对填充墙框架和空框架结构进行了多遇及罕遇地震下的时程反应分析，通过耗能机制分析，表明了填充墙是结构非弹性耗能的主要构件，在结构耗能中起着积极的作用；并通过内力分析，指出填充墙与框架结构的相互作用改变了框架结构的内力分布，并增大了柱端分担的弯矩及轴力，造成设计中对柱内力估计的偏差。2.揭示了计算模型误差是产生“强梁弱柱”的原因之一。结合精细有限元模型，分析了目前广泛使用的简化有限元模型误差产生的原因，并通过不同荷载工况下两种计算模型内力分布的比较，指出简化有限元模型不能很好地反映楼板的实际参与作用，导致低估了框架柱承担的弯矩，造成地震中柱先于梁发生破坏。3.提出了板壳耦合梁板模型。针对简化有限元模型不能合理考虑楼板影响的不足，本文对现有的刚臂耦合梁板模型进行了改进，提出了板壳耦合梁板模型，通过不同荷载工况下内力分布的比较，表明该模型的计算精度较简化有限元模型有较大的改善，而在相同精度的前提下，则比刚臂耦合梁板模型更具有计算上的优势。4.楼板能显著提高梁端负弯矩承载力并影响“强柱弱梁”的形成。将梁和板简化为不同有效翼缘宽度的T型梁，通过静力和动力作用下的反应分析，讨论了不同有效宽度楼板对梁端弯矩承载力及屈服机制的影响，指出板筋参与比例是重要参数，并通过耗能机制分析进一步说明了由于楼板的影响，柱子成为主要的耗能构件，在地震中破坏相对较重。更多还原

【Abstract】 ’Strong column and weak beam’ is one of fundamental design principlesfor earthquake-resistant structures. It is expected that seismic energy isdissipated by the damage of beams prior to columns, thus structures cannot gofar as to collapse in strong earthquake. However, investigations of earthquakedamage have shown that more RC structures are damaged in ‘strong columnand weak beam’ pattern, rather than ‘strong beam and weak column’ pattern.The formation of ‘strong column and weak beam’ pattern is influencedby many factors, mainly as follows: the contribution of floors, the influence ofinfill walls, the strong beams and overreinforced beams, etc. Moreover, infillwalls are usually treated as non-structural components in seismic design, notinvolved in the seismic analysis However, a large number of earthquakedamage of structures have reveals that the contribution of infill walls cannotbe ignored for seismic performance of structures.In this paper, the influences of infill walls and the mechanism of ‘strongbeam and weak column’ pattern are studied, and the main work and results areas follows:1. Infill walls play an important role in energy dissipation and theredistribution of internal force for frame structures. Many time historyresponses of infill wall frame and bare frame structures are analyzed underfrequent and rare earthquake excitation. In light of energy dissipationmechanism analysis, it shows that infill wall is the main non-elastic energydissipative component for the frame structure; And the interaction betweeninfill walls and frame structure results in the redistribution of the internalforce in frame structures, namely, the distributed moment and axial force ofthe column increased, which is responsible for the estimation deviation of theinternal of force columns in structure design.2. The deviation of the analysis model is one of the causes for the ‘strongbeam and weak column’ pattern. Combined with the fine finite element model,the sources of the deviation of the simplified finite element model, which iswidely used nowadays, are analyzed. Meanwhile, through the internal forcedistribution comparison between the two models under different loads, it isrevealed that the contribution of floor slab is fully considered in the simplifiedfinite element model, thus the bearing moment of the columns is underestimated, leading to the columns damage prior to beams in earthquakes.3. The girder-slab coupled shells model is proposed. To improve thesimplified finite element model, which underestimates the contribution of thefloor slab, and the girder-slab coupled shells model are proposed based on thegirder-slab coupled rigid arm model. By comparing the internal forcedistribution under different loads, it is demonstrated that the new model ismore accurate than the simplified finite element model; moreover, with thesame computational accuracy requirement, the new model is more efficientthan the girder-slab coupled rigid arm model.4. The floor slab can significantly improve the bearing negative momentof beam ends, and promote the ‘strong column and weak beam’. Bysimplifying both beam and slab into T-shape beams with different effectiveflange width, with the static and dynamic analysis of the two T-shape beams,the influence of different effective width on the bearing moment of beam andyield mechanism is discussed, and the participating ratio of steel bars in slabis an important parameter. With energy dissipation mechanism analysis, itfurther indicate that columns have become the main energy dissipativecomponents due to the contribution of floor, therefore, the column usuallydamage more severely in earthquakes.更多还原