强震作用下混凝土砌块配筋砌体结构破坏形态研究

通过对6层适量注芯混凝土小型空心砌块配筋砌体结构模型进行地震模拟振动台试验,分析模型结构的位移反应、最大层间位移角及裂缝发生、发展规律等,研究其在7度构造措施条件下的结构破坏形态、屈服机制。试验结果表明:配筋砌体模型结构在地震动下的整体变形仍以剪切变形为主;圈梁、构造柱以及水平拉结筋构成的约束体系作用非常明显,结构在中强地震作用下抗疲劳破坏能力较强,完全能够满足抗震规范规定的在7度区"大震不倒"的要求;结构在罕遇地震作用下也具有相当的抗震能力,且层数和房屋高度都可适当提高。结构在严重破坏时,形成以门洞"连梁"为塑性铰且类似于框架结构的"强柱弱梁"型总体屈服机制。作构件细部设计时,应充分考虑压、剪、弯的共同作用,确保构件的强度和延性,避免结构形成层间屈服机制和发生局部破坏。

Study on failure shape of reinforced concrete block masonry structure under strong earthquake

Based on the earthquake simulations by shaking table for a 6-story reinforced concrete hollow block masonry structure with injection efficiency,the deformation response of model structure,the occurrence and development of the maximum story drift/cracks as well as the structural failure mode/yielding mechanism under 7-intensity details of seismic design were studied.The experimental results indicate that under earthquake ground motion,the shear deformation is the major behavior of reinforced masonry structure;the role of restraint system composed of ring beams,structural columns and horizontal tie bars is obvious,under moderate seismic indensity the structure has a good fatigue resistance,and may satisfy the requirement of "no collapse due to strong earthquake" specified for 7-intensity seismic area;the structure also has a good resistance to rare earthquakes so that the number of stories and building height may be appropriately increased.When the structure was seriously damaged,a global yield mechanism which is similar to the "strong column,weak beam" type was developed with the spandrel beams as plastic hinges.Hence,in design of member details,the combined actions of compression,shearing and bending should be considered adequately to ensure the strength and ductility of members and avoid story yield mechanism as well as local failure.