考虑平面内外性能耦合的填充墙-RC框架协同工作机制及反应修正系数研究

Masonry-infilled reinforced concrete (RC) frames are widely used in the whole of the world. Infilled RC frames will suffer in-plane and out-of-plane load simultaneously under seismic excitation. There are significant coupling effects between in-plane and out-of-plane behavior of masonry-infilled RC frame. Most existing researches focus on the in-plane seismic performance of the infilled RC frame. Unfortunately, the researches on the interaction mechanism of the infilled RC frame considering the coupling effects between in-plane and out-of-plane behavior are rare. The response modification factor is used to reduce the elastic responses under the design seismic intensity to obtain the design seismic force. The values of the response modification factors in the current seismic codes all over the world are based largely on judgments of engineers, which do not consider the influence of infill walls. This project will carry out pseudo-static tests of the infilled RC frame under in-plane and out-of-plane loads. Based on the experimental results, this project will develop a three-dimension refined finite element model of the infilled RC frame to study the infill RC frame interaction mechanism consider the in-plane and out-of-plane performance coupling effect. This project will develop a reasonable and effective simplified model to reveal the global failure mechanism under in-plane and out-of-plane loads. This project also aims to conduct capacity and demand analysis for response modification factors of infilled RC frames. And deterministically and probabilistically assess the response modification factors of these structures from the viewpoint of certainty and uncertainty respectively. Based on the above analytical study, the recommended values of the response modification factors for infilled RC frame structures are suggested.

填充墙RC框架结构在全世界范围内广泛存在，地震作用下填充墙RC框架结构同时受到平面内和平面外荷载作用，填充墙平面内外性能存在较强的耦合效应。目前的研究大都局限于填充墙RC框架结构平面内的抗震性能，关于考虑平面内外性能耦合效应的填充墙-框架（墙-框）协同工作机制的研究则非常有限。反应修正系数是对结构在设防烈度下的弹性反应进行折减来确定地震力，各国规范的反应修正系数主要都是根据经验确定的，均没有考虑填充墙的影响。本项目将进行填充墙RC框架结构在平面内外共同加载下的拟静力试验研究，建立三维精细化有限元模型，研究平面内外性能耦合下的墙-框协同工作机制，发展合理有效的简化模型。利用简化模型揭示平面内外荷载共同作用下填充墙RC框架整体结构失效机制，对我国填充墙RC框架结构反应修正系数进行能力与需求分析，从确定性和不确定性的角度对其进行科学的评定，并给出考虑填充墙影响的RC框架结构反应修正系数的建议值。

填充墙 RC 框架结构在全世界广泛存在，在地震作用下填充墙平面内外性能存在较强的耦合效应。本项目进行了填充墙 RC 框架结构在平面内外共同加载下的拟静力试验，根据试验结果分析了各试件的滞回曲线、骨架线、强度、刚度和耗能能力等抗震性能指标，研究了维持与不维持平面内荷载情况下的平面外抗震性能，以及开洞填充墙和FRP加固填充墙的平面内外抗震性能；建立了精细化有限元模型，通过试验结果验证了有限元模型的可靠性，并对多种影响参数进行了敏感性分析。研究了填充墙高厚比、高宽比、砌体抗压强度及平面内卸载与维持加载等参数对填充墙RC框架结构平面内外抗震性能的影响，研究了平面内外性能耦合下的墙-框协同工作机制；提出了一种考虑填充墙平面内外性能耦合的简化模型，将填充墙简化为四个刚性杆和一个中间的弹塑性杆，对中间的弹塑性杆设置分开式梁柱单元截面，利用本项目试验及文献中的试验验证了简化模型的准确性，并研究了填充墙的不同竖向布置方案对结构抗震性能的影响；研究了考虑双向地震作用的填充墙对RC框架结构反应修正系数能力值和需求值的影响，并对其进行科学的评定，为促进我国建筑结构抗震设计和分析中考虑填充墙的刚度和承载力提供了理论参考。本项目按照预期目标圆满完成了填充墙平面内外性能耦合效应的拟静力试验研究、精细化有限元数值模拟研究、五撑杆简化模型研究和结构反应修正系数的研究。