为对某连续刚构桥进行状态评估,结合时变可靠度研究方法,考虑混凝土强度时变效应和预应力筋强度时变效应等因素,建立其时变可靠度模型,通过有限元软件进行模拟分析,采用不确定分析手段,对桥梁的相关统计参数进行抽样,对其连续刚构段进...为对某连续刚构桥进行状态评估,结合时变可靠度研究方法,考虑混凝土强度时变效应和预应力筋强度时变效应等因素,建立其时变可靠度模型,通过有限元软件进行模拟分析,采用不确定分析手段,对桥梁的相关统计参数进行抽样,对其连续刚构段进行计算,计算考虑时变因素下的桥梁失效概率并研究时变效应对评估桥梁失效概率的影响,得到设计使用年限内服役时间与可靠度指标之间的关系,对桥梁状态进行评估。研究表明,基于可靠度方法对现役桥梁状态进行评估时,考虑混凝土强度时变效应和预应力筋强度的时变效应计算得到的失效概率曲线斜率均大于不考虑时变效应时的曲线斜率,对桥梁状态预测的结果更为安全。For the state assessment of a certain continuous rigid-frame bridge, combined with the time-varying reliability research method, factors such as the time-varying effect of concrete strength and the time-varying effect of prestressed tendon strength are considered to establish its time-varying reliability model. Simulation analysis is conducted through finite-element software. Uncertainty analysis methods are used to sample the relevant statistical parameters of the bridge, and calculations are made for its continuous rigid-frame section to calculate the bridge failure probability considering time-varying factors and to study the impact of time-varying effects on the bridge failure probability. The relationship between the service time within the design service life and the reliability index is obtained to evaluate the bridge state. Research shows that when evaluating the state of existing bridges based on the reliability method, the slopes of the failure probability curves calculated by considering the time-varying effects of concrete strength and prestressed tendon strength are both greater than those of the curves without considering the time-varying effects, and the results of bridge state prediction are more reliable.展开更多
某一特定场地的岩土力学参数在地质作用下普遍呈现固有的不确定性,融合现场观测数据进行概率反分析可有效缩减这一不确定性。虽然基于子集模拟的贝叶斯更新(Bayesian Updating with Subset simulation,简称BUS)方法可以将等量场地信息...某一特定场地的岩土力学参数在地质作用下普遍呈现固有的不确定性,融合现场观测数据进行概率反分析可有效缩减这一不确定性。虽然基于子集模拟的贝叶斯更新(Bayesian Updating with Subset simulation,简称BUS)方法可以将等量场地信息的高维概率反分析问题转化为等效的结构可靠度问题,但是当现场观测数据增多时,构建的似然函数值会变得非常小,甚至低于计算机浮点运算精度,会严重影响概率反分析计算效率与精度。为此,提出了一种基于并联系统可靠度分析的改进BUS方法,从基于乔列斯基分解的中点法出发,将接受率低的总失效区域分解为多个接受率高的子失效区域,从而避免因融合大量现场观测数据引起的“维度灾难”问题,实现对边坡岩土力学参数的准确概率反分析。最后,通过一不排水饱和黏土边坡案例验证了提出方法的有效性,结果表明提出的方法能够融合大量钻孔数据和边坡服役状态等观测信息高效进行岩土力学参数概率反分析及边坡可靠度评估,为高维空间变异参数概率反分析和边坡可靠度评估提供了一种有效的工具。展开更多
文摘为对某连续刚构桥进行状态评估,结合时变可靠度研究方法,考虑混凝土强度时变效应和预应力筋强度时变效应等因素,建立其时变可靠度模型,通过有限元软件进行模拟分析,采用不确定分析手段,对桥梁的相关统计参数进行抽样,对其连续刚构段进行计算,计算考虑时变因素下的桥梁失效概率并研究时变效应对评估桥梁失效概率的影响,得到设计使用年限内服役时间与可靠度指标之间的关系,对桥梁状态进行评估。研究表明,基于可靠度方法对现役桥梁状态进行评估时,考虑混凝土强度时变效应和预应力筋强度的时变效应计算得到的失效概率曲线斜率均大于不考虑时变效应时的曲线斜率,对桥梁状态预测的结果更为安全。For the state assessment of a certain continuous rigid-frame bridge, combined with the time-varying reliability research method, factors such as the time-varying effect of concrete strength and the time-varying effect of prestressed tendon strength are considered to establish its time-varying reliability model. Simulation analysis is conducted through finite-element software. Uncertainty analysis methods are used to sample the relevant statistical parameters of the bridge, and calculations are made for its continuous rigid-frame section to calculate the bridge failure probability considering time-varying factors and to study the impact of time-varying effects on the bridge failure probability. The relationship between the service time within the design service life and the reliability index is obtained to evaluate the bridge state. Research shows that when evaluating the state of existing bridges based on the reliability method, the slopes of the failure probability curves calculated by considering the time-varying effects of concrete strength and prestressed tendon strength are both greater than those of the curves without considering the time-varying effects, and the results of bridge state prediction are more reliable.
文摘某一特定场地的岩土力学参数在地质作用下普遍呈现固有的不确定性,融合现场观测数据进行概率反分析可有效缩减这一不确定性。虽然基于子集模拟的贝叶斯更新(Bayesian Updating with Subset simulation,简称BUS)方法可以将等量场地信息的高维概率反分析问题转化为等效的结构可靠度问题,但是当现场观测数据增多时,构建的似然函数值会变得非常小,甚至低于计算机浮点运算精度,会严重影响概率反分析计算效率与精度。为此,提出了一种基于并联系统可靠度分析的改进BUS方法,从基于乔列斯基分解的中点法出发,将接受率低的总失效区域分解为多个接受率高的子失效区域,从而避免因融合大量现场观测数据引起的“维度灾难”问题,实现对边坡岩土力学参数的准确概率反分析。最后,通过一不排水饱和黏土边坡案例验证了提出方法的有效性,结果表明提出的方法能够融合大量钻孔数据和边坡服役状态等观测信息高效进行岩土力学参数概率反分析及边坡可靠度评估,为高维空间变异参数概率反分析和边坡可靠度评估提供了一种有效的工具。
