汶川地震后绵竹、都江堰市房屋震害调查与分析

Investigations of Building Damages in Mianzhu and Dujiangyan Due to 5·12 Wenchuan Earthquake

依据笔者在四川省绵竹市、都江堰市参加建设部组织的汶川地震震后房屋应急评估所取得的资料,对该次地震造成的建筑结构破坏进行了分析,从砖砌体结构、混凝土框架结构、构造问题以及设计与施工缺陷4个方面,论述了各种破坏的形态与成因,讨论了现行设计方法中存在的问题,提出了相应的改进建议。主要结论有:砌体结构的底层墙体强度不足、开间过大、形体复杂是导致其破坏的重要原因,在设计中,应适当提高砌体结构底层墙体的强度,控制房屋的开间,加强形体变化部位;砌体结构的窗下墙应作为连接墙肢的连梁考虑,可以将其设计成抗震设防的第一道防线;框架结构设计中,应考虑框架与填充墙的相互作用,考虑楼梯斜梁或斜板参与结构的整体受力;在现行规范要求的基础上,要适当增加框架柱的截面,节点附近的箍筋应采用焊接封闭箍或螺旋箍;应加强非结构构件的连接与锚固;对乡村房屋建设应予以监管,杜绝结构体系不明确的房屋出现。

The seismic damages of buildings were investigated according to the information obtained by the authors from Post 5.12 Wenchuan earthquake emergency hazard assessment of buildings sponsored by the Ministry of Construction.The patterns and the causes of building damages were studied from the aspects of brick structures,RC frame structures,conformation problems,and defects in design or construction.Problems in structural design were discussed,and suggestions to solve these problems were proposed.Main conclusions are as follows： The insufficient strength of bottom walls,large space in plan,and complex shapes are the significant damaging causes of brick structures.Therefore,the strength of bottom walls should be improved,the space between two structural walls should be limited in a reasonable range,and the members in the places of varied configuration of buildings should be strengthened.The wall under windows may be taken as a coupling beam and should be designed as the seismic resistance member in the first order.The frame-infill interaction should be considered in RC frame design.Sections of columns of RC frames should be enlarged on the basis of design codes.Stirrups in columns near the joint should be closed or shaped as a helix.The anchor and joint of non-structural member should be strengthened.Plates or the beams of stairs should be taken into account to evaluate the general behavior of the structures subjected to seismic action.Constructions in rural areas must be supervised so that the incorrect structural system may be eliminated.