农村住宅砌体结构地震破坏数值模拟研究

Numerical Simulation of Earthquake Damage in Rural Masonry Buildings

国内震害调查表明我国农村房屋在地震中破坏严重,主要原因是农村自建房屋大都缺乏基本抗震措施。近年来有关部门针对农村房屋的抗震性能提出一些改进措施,但这些措施实际抗震效果如何,除了极少数通过模型试验验证外,很少得到验证。本文建立了砌体结构非线性有限元分析模型,以一幢农宅为研究对象,通过地震时程反应来再现其在地震作用下的破坏状况。研究表明本文提出数值模型能够较好的模拟砌体结构在地震中破坏过程,发现结构抗震薄弱部位。通过对三种模型对比分析表明圈梁和构造柱可以有效提高砌体结构整体抗震性能,但对局部破坏影响不大,需要在以后抗震设计中加以考虑。

Earthquake experience indicates that the buildings of the countryside have sustained more serious damage and destruction than city buildings during recent earthquakes in China.A main reason is that rural buildings have not been strictly designed and constructed according to codes.The Code for Seismic Design of Buildings has been under development for fifty years in China,but it has been given few chances to guide building construction at the countryside＇s lower economic level.Rural buildings have been constructed by the owners themselves and lack basic earthquake provisions,causing rural buildings to be easily damaged during earthquakes.For this reason,some measures have been proposed in recent years for improving the seismic performance of rural buildings.But most earthquake guidelines have not been verified by building model experiments or actual earthquake experiences.Fortunately,as numerical simulation skills develop,it is becoming possible to simulate the entire earthquake response process for a building.This study proposed a numerical dynamic inelastic earthquake response model for a single-story unreinforced masonry building,using the ABAQUS program.Three levels of earthquake provision were considered：（1） the unreinforced masonry building,with no reinforced concrete（RC） tie columns or RC tie beams;（2） the unreinforced masonry building,including RC tie columns and RC tie beams;（3） the masonry building with reinforced steel in the corners and joints between the horizontal wall and the longitudinal wall and including RC tie columns and RC tie beams.Concrete damaged plasticity was used to represent the behavior of the masonry wall.Masonry in compression was modeled as an elastic-plastic material,and the stress-strain behavior of concrete in compression was assumed to be linear elastic.The earthquake response processes of the three models were simulated from the record of the Wenchuan earthquake,located in Wen County of GanSu province.The analysis results indicated that the numerical method is a better tool for simulating the masonry building earthquake response process.The earthquake measures are very important for improving buildings in the countryside.