一种混凝土箱梁桥的可靠性评估方法

发布时间：2018-09-10 10:57

【摘要】：为评估混凝土箱梁桥正常运营期间的安全状态,基于桥梁健康监测数据与可靠度理论,以混凝土抗拉强度标准值为抗力,车辆荷载响应和竖向温度梯度荷载响应为荷载效应,建立正常使用极限状态方程.对于实桥监测的综合荷载应变响应,利用经验模态分解方法提取箱梁顶底板应变响应的温度趋势项,并对车辆荷载响应和竖向温度梯度响应进行概率密度函数拟合;对非正态分布的荷载效应当量正态化,计算最不利组合下箱梁跨中截面顶底板的失效概率.结果表明:监测的车辆荷载响应和竖向温度梯度荷载响应的概率密度函数均不满足正态分布,采用广义极值分布具有较好的拟合效果;箱梁顶底板的失效概率均小于1%,并在车辆荷载和竖向温度梯度的共同作用下,底板的失效概率显著升高.
[Abstract]:In order to evaluate the safety state of concrete box girder bridge during normal operation, based on the bridge health monitoring data and reliability theory, the standard value of concrete tensile strength is taken as the resistance, and the load response of vehicle and vertical temperature gradient load is regarded as load effect. The limit state equation of normal use is established. For the comprehensive load strain response monitored by real bridge, the temperature trend term of the top and bottom plate strain response of box girder is extracted by empirical mode decomposition method, and the probability density function fitting of vehicle load response and vertical temperature gradient response is carried out. For the equivalent normalization of the load effect of non-normal distribution, the failure probability of the top and bottom plate of the middle section of the box girder is calculated under the most unfavorable combination. The results show that the probability density function of the monitored vehicle load response and vertical temperature gradient load response does not satisfy the normal distribution, and the generalized extreme value distribution has a better fitting effect. The failure probability of the top and bottom plate of the box girder is less than 1, and the failure probability of the bottom plate increases significantly under the combined action of vehicle load and vertical temperature gradient.
【作者单位】：哈尔滨工业大学交通科学与工程学院;浙江大学宁波理工学院土木建筑工程学院;
【基金】：国家自然科学基金(50678051) 黑龙江省交通运输厅科技重点项目(E201110)
【分类号】：U446

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