摘要
主震之后往往伴随着大量的余震,余震对结构的影响可能大于主震。文章以钢筋混凝土桥墩为研究对象,利用OpenSees软件建立纤维单元有限元模型,以实际记录的主余震地震波进行主震、主-余震非线性时程分析,对阻尼比分别为0.03、0.05、0.07、0.09、0.11的桥墩进行滞回曲线、最大位移、耗能及残余位移对比。研究结果表明:随阻尼比的增加,墩柱的自由衰减逐渐加快,桥墩在地震过后自由衰减是围绕损伤桥墩静平衡位置发生的,余震引起桥墩的位移需求均大于主震;阻尼比的增大不仅有利于改善桥墩抵抗主震的能力,对于抵抗余震的能力也有一定的提高。然而,主震、主余震作用下墩柱对于剪力的需求基本不变。桥墩滞回曲线的耗能随阻尼比的增加逐渐减小,主余震作用下桥墩的耗能大约为主震的一倍,对于耗能能力差的结构,余震的影响可能更大,余震引起的损伤主要是通过滞回耗能增加了桥墩的损伤。桥墩在主余震作用下残余位移均相差不大,余震不仅可以增加桥墩的残余位移,也可能存在反方向地震力而使桥墩残余位移减小。工程中可以通过增加阻尼器来增强桥墩抵御余震的影响。
Often there are post-earthquakes following the main-earthquakes,and the former has more influence on the structure than the latter.This paper takes reinforced concrete pier as the research object,and builds finite model of fiber element with OpenSees Software.Nonlinear time history analysis of main-earthquakes and main-post-earthquakes based on actual recorded seismic waves is carried out.Compare the hysteresis curves,maximum displacements,energy consumptions and residual displacements of piers with damping ratios of 0.03,0.05,0.07,0.09 and 0.11.The results show that with the increase of damping ratio,the free attenuation of the pier gradually accelerates,and the free attenuation of the pier after the earthquake occurs around damaging the pier static equilibrium position.The displacement demand caused by post-earthquakes is greater than that of the main-earthquakes.The increase of damp-ing ratio is not only conducive to improve the ability of bridge piers to resist main-earthquakes,but also to improve the ability to resist post-earthquakes.However,the demand for shear force of piers is basically unchanged under the action of main-earthquakes and main-post-earthquakes.With the increase of damping ratio,the energy consumption of the bridge piers hysteresis curve decreases gradually.The energy consumption of the bridge piers under the action of the main-post-earthquakes is about twice that of the main-earthquakes.For structures with poor energy consumption capacity,the post-earthquakes may have a greater impact.The damage caused by post-earthquakes mainly increases the damage of piers through hysteretic energy consumption.The residual displacement of the bridge piers under the action of the main-post-earthquakes has litle difference.The post-earthquakes can not only increase the residual displacement of the bridge pier,but also may have the reverse seismic force that can reduce the residual displacement of the bridge pier.In engineering practice,dampers can be added to strengthen the pier to resist the impact of post-earthquakes.
作者
康斌锴
王雪玮
任润田
KANG Bin-kai;WANG Xue-wei;REN Run-tian
出处
《内蒙古公路与运输》
2023年第1期33-37,42,共6页
Highways & Transportation in Inner Mongolia
关键词
桥梁工程
抗震性能研究
有限元分析
阻尼比
主-余震
bridge engineering
seismic performance research
finite element analysis
damping ratio
main-post-earthquake
