楼板对rc框架结构强柱弱梁屈服机制的影响.pdf

Classified Index: : Dissertation for the Master Degree in Engineering THE EFFECT OF SLABS ON STRONG COLUMN-WEAK BEAM MECHANISM OF RC FRAME STRUCTURES Candidate: Sun Yang Supervisor: Prof. Xie Lili, Member of CAE Vice Supervisor: Associate Prof. Zhai Changhai Academic Degree Applied for: Master of Engineering Speciality: Structural Engineering Affiliation: School of Civi l Engineering Date of Defence: July, 2010 Degree-Conferring -Institution: Harbin Institute of Technology 哈尔滨工业大学工学硕士学位论文-I- 摘要 汶川大地震中,钢筋混凝土框架结构普遍出现“强梁弱柱”的破坏模式,规范所要求的“强柱弱梁”破坏模式未能实现,究其原因,没有合理考虑楼板对框架梁抗弯能力的增强作用是其中的一个重要因素。在结构设计和分析中,由于现浇楼板与框架间相互作用的复杂性,一般假定楼板是刚性的,近似考虑了楼板对框架梁刚度的影响,而忽略了楼板对框架梁抗弯能力的增强作用。这种简化的处理方式不仅不符合实际,而且会使结构产生以柱铰为主的屈服耗能机制,其危害是巨大的,因此有必要研究现浇楼板对框架结构工作性能的影响。针对钢筋混凝土框架结构未能实现“强柱弱梁”屈服耗能机制的破坏现象,本文定量的评估现浇楼板对框架结构抗震性能的影响。主要包括以下内容: 1) 对考虑楼板的框架结构的试验和理论分析资料进行总结, 分析楼板对框架结构地震反应的影响规律。 2) 分别建立考虑楼板和不考虑楼板的框架结构实体模型, 采用静力侧向加载的方法,对比分析两种框架结构的强度和刚度性能,通过观察不同侧移下楼板钢筋参与梁端抗负弯矩作用的范围,折算楼板有效宽度。 3) 根据不同的柱端弯矩增大系数, 分别建立按规范设计的考虑楼板和不考虑楼板的框架结构模型,采用动力时程分析方法对上述两类框架结构进行抗震性能分析,通过分析结构在罕遇地震下的顶点侧移、层间位移角和塑性铰分布,寻求合理的柱端弯矩增大系数。 4) 通过上述分析, 对现浇楼板框架结构未能实现规范要求的“强柱弱梁”失效模式提出改进建议,并给出定量的分析结果。关键词 强柱弱梁;柱端弯矩增大系数;楼板有效宽度;塑性铰哈尔滨工业大学工学硕士学位论文-II- Abstract In Wenchuan Earthquake, one of the majo r failure modes of frame structures is the strong beam-weak column mode, which illustrates that the strong column-weak beam mode requ ired by the Chinese seismic code fails to realize. One of the main reasons is that the effect of slabs is not appropriately taken into account. Because of plexity of frame-slab interaction, the slab is often assumed to be rigid, approximatively c onsidering the influences of slabs on frame beam stiffness. However, the influenc es of slabs on fram e beam strength is neglected in structural design and an alysis. This simplif ied approach is impractical, and leads the major failure mo de of the frame structures to plastic hinge mode in column. Because such da mage is enormous