【作者】 周政； 陈国海； 杨迪雄；

【Author】 Zheng Zhou;Guohai Chen;Dixiong Yang;Department of Engineering Mechanics,Dalian University of Technology;

【机构】 大连理工大学工程力学系；

【摘要】 连续梁桥具有整体性强、刚度大、承载能力高、用料节省等优点,是目前应用最广泛的桥梁类型。本文以连续梁桥为研究对象,考虑近断层地震动的随机不确定性,提出了一种基于直接概率积分法的桥梁结构非线性随机振动响应和动力可靠度分析的新框架。首先,建立了包含速度脉冲的近断层地震动随机模型,合成了近断层脉冲型地震动时程。进一步,利用开源软件OpenSees建立了连续梁桥的确定性有限元模型。通过联立连续梁桥确定性动力学方程和概率密度积分方程,求得了连续梁桥顺桥向和横桥向随机振动响应的概率密度函数。最后,采用多种失效准则,考察了近断层地震动对连续梁桥的动力可靠度影响。结果表明:基于直接概率积分法的桥梁随机动力学分析通用框架可以准确高效地获得其随机振动响应的概率信息。此外,在桥梁动力可靠度分析中应用地震易损性概念,可以清楚获知桥梁构件进入不同损伤状态的概率,为桥梁监测不同构件在地震作用下的损伤状态提供新的思路。更多还原

【Abstract】 The continuous girder bridge has the advantages of strong integrity,large rigidity,high bearing capacity and material saving,which is the most widely used bridge type at present.This paper takes the continuous girder bridge as the research object with considering the random uncertainty of the near-fault ground motions,and puts forward a new framework based on the direct probability integral method for nonlinear random vibration responses and dynamic reliability analysis of bridge structure.Firstly,the stochastic model of near-fault ground motions with velocity pulses is established,and the time histories of near-fault pulse-like ground motions are synthesized.Furthermore,the deterministic finite element model of continuous girder bridge is established by using open source software OpenSees.Based on the deterministic dynamics equation and probability density integral equation of a continuous bridge,the probability density functions of random vibration responses of a continuous bridge along and across the bridge are obtained.Finally,the influence of near-fault stochastic ground motions on dynamic reliability of continuous girder bridge is investigated by adopting multiple failure criteria.The results show that the general framework for random dynamic analysis of bridge based on direct probability integral method can accurately and efficiently achieve the probability information of random vibration responses.In addition,by applying the concept of seismic vulnerability in dynamic reliability analysis of bridges,the probability of bridge members reaching different damage states can be clearly known,which provides a new idea for monitoring the damage states of different bridge members under earthquake action.更多还原