基于有限元法的土坯民房地震响应分析研究
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摘要
基于有限元法研究了土坯民房的地震响应特征,提出了实施土坯民房震害防治的对策性建议。地震动由结构底部向上传播时,低频部分被墙体吸收,水平加速度逐渐增大,揭示了低破坏性地震动损伤土坯民房屋盖系统、高破坏性地震动损坏土坯民房承重构件,进而导致整体结构损毁的动力机制。砖柱(木柱)承重土坯民房的地震响应大于墙体承重土坯民房,后者最大剪应力集中在中间开间的横墙和纵墙的连接处,最大主应力集中在中间开间的横墙上;前者最大剪应力集中在横墙和柱的连接处,最大主应力集中在中间开间的柱体上部。由于2种结构类型土坯民房的薄弱环节有所不同,地震时的致灾原因亦存在差异。
The characteristics of structural response of rural adobe-structure buildings to earthquakes have been analyzed with the finite element method(FEM) to provide suggestions on policy for prevention of seismic disaster.The seismic response analysis shows that the part of seismic energy in the lower range of frequency is absorbed by adobe-walls and the horizontal acceleration is magnified in the upward propagation of the seismic wave.The result reveals the seismic damage mechanism that a small earthquake is likely to destroy the roof of adobestructure buildings whereas a large one may selectively destroy the load-bearing components,i.e.walls or columns,which results in the collapse of the overall building.The seismic response of an adobe-structure building with brick/wood columns as the load-bearing component is much larger than that of a similar building with its walls as the load-bearing component.In the standard middle room, the former has the maximal shearing stress at joints of columns and cross-filled walls,and the maximal principal stress on tops of columns;the latter has the maximal shearing stress at joints of longitudinal and transverse walls,and the maximal principal stress in transverse walls,in the middle room as well.The seismic damage mechanisms of the two types of adobe-structure buildings are different since they have different weak sections.
The characteristics of structural response of rural adobe-structure buildings to earthquakes have been analyzed with the finite element method(FEM) to provide suggestions on policy for prevention of seismic disaster.The seismic response analysis shows that the part of seismic energy in the lower range of frequency is absorbed by adobe-walls and the horizontal acceleration is magnified in the upward propagation of the seismic wave.The result reveals the seismic damage mechanism that a small earthquake is likely to destroy the roof of adobestructure buildings whereas a large one may selectively destroy the load-bearing components,i.e.walls or columns,which results in the collapse of the overall building.The seismic response of an adobe-structure building with brick/wood columns as the load-bearing component is much larger than that of a similar building with its walls as the load-bearing component.In the standard middle room, the former has the maximal shearing stress at joints of columns and cross-filled walls,and the maximal principal stress on tops of columns;the latter has the maximal shearing stress at joints of longitudinal and transverse walls,and the maximal principal stress in transverse walls,in the middle room as well.The seismic damage mechanisms of the two types of adobe-structure buildings are different since they have different weak sections.
引文
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[2]GB 18306-2001,中国地震动参数区划图[S].
[3]范迪璞,等.村镇房屋抗震与设计[M].北京:科学出版社,1991.Fan D P,et al.Reinforcement and Design for Housesin Rural Areas[M].Beijing:Science Press,1991.
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[5]石玉成,林学文,王兰民,等.黄土地区生土建筑震害特征及防灾对策研究[J].自然灾害学报,2003,12(3):87-92.Shi Y C,Lin X W,Wang L M,et al.Earthquakedamage characteristics of raw soil buildings in loessareas and disaster prevention countermeasures[J].Journal of Natural Disasters,2003,12(3):87-92.
[6]王峻.黄土地区农村民房生土建筑土墙体材料抗震性能的试验研究[J].西北地震学报,2005,27(2):158-162.Wang J.Study on seismic resistance performance ofwall material used in rural raw-soil buildings in loessarea[J].Northwestern Seismological Journal,2005,27(2):158-162.
[2]GB 18306-2001,中国地震动参数区划图[S].
[3]范迪璞,等.村镇房屋抗震与设计[M].北京:科学出版社,1991.Fan D P,et al.Reinforcement and Design for Housesin Rural Areas[M].Beijing:Science Press,1991.
[4]石玉成,王兰民,林学文,等.黄土生土建筑震害预测研究[J].西北地震学报,2004,26(3):206-211.Shi Y C,Wang L M,Lin X W,et al.Prediction onearthquake damage of raw soil buildings in loess area[J].Northwestern Seismological Journal,2004,26(3):206-211.
[5]石玉成,林学文,王兰民,等.黄土地区生土建筑震害特征及防灾对策研究[J].自然灾害学报,2003,12(3):87-92.Shi Y C,Lin X W,Wang L M,et al.Earthquakedamage characteristics of raw soil buildings in loessareas and disaster prevention countermeasures[J].Journal of Natural Disasters,2003,12(3):87-92.
[6]王峻.黄土地区农村民房生土建筑土墙体材料抗震性能的试验研究[J].西北地震学报,2005,27(2):158-162.Wang J.Study on seismic resistance performance ofwall material used in rural raw-soil buildings in loessarea[J].Northwestern Seismological Journal,2005,27(2):158-162.
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