汶川地震中房屋建筑震害特征及抗震设计思考

Characteristic Analysis of Performance and Damage of Buildings in Wenchuan Earthquake and Considerations in Aseismic Design of Buildings

汶川5·12特大地震造成了为数众多的建筑物不同程度的损坏。地震发生后,四川大学随即组织了现场勘查队奔赴受灾最为严重的地区了解建筑物的受损情况。本文基于大量的现场勘查资料介绍了砌体结构、框架结构、底框或局部底框砌体结构及楼梯间的震害特点。在定性分析的基础上提出以下观点:合理设计和施工的砌体结构有可能获得良好的抗震性能;按现行规范设计的钢筋混凝土框架结构难以实现"强柱弱梁"的要求;填充墙对框架抗震性能有显著的影响;在地震区应慎用底框砌体结构;合理的结构布置和施工质量是结构获得良好抗震性能的前提;仅用延性系数来衡量结构抗震性能具有一定的片面性;楼梯间结构设计宜考虑地震作用的影响。

An 8.0 magnitude earthquake attacked the northwestern margin of the Sichuan Basin on May 12, 2008. The epicenter was located somewhere near Yingxiu Town, Wenchuan County. A large number of buildings were damaged to different degrees in the epicenter region. Based on large amounts of statistical data from the field investigation, this paper presents the characteristics of performance and damage of buildings of such types as masonry, infilled RC frame, masonry with ground RC frame or local ground RC frame, and staircase. Code requirements in aseismic design are discussed together with a qualitative analysis of the observed damage of structures. The earthquake has revealed many structural deficiencies, such as poor detailing in a masonry structure, soft-columns and strong-beams, soft and weak stories in a frame, poor layout of infilled walls, and poor quality of construction. Finally, we make some points as follows： （1） besides RC structures, masonry structures are also suitable to resist earthquakes if they are properly designed together with good detailing and high quality of construction; （2） disregard of the effect of in-filled walls in structural designs was one of the main reasons for the widespread destruction of RC frames in the epicenter region; （3） the detailing of stairwells should be designed by considering earthquake effect.