基于车辆荷载效应截尾分布的桥梁限载分析方法

发布时间：2018-09-03 20:09

【摘要】：根据车辆荷载效应右截尾分布模型,提出一种基于结构可靠度理论的中、小跨度桥梁限载分析方法。首先以规范规定的车辆荷载效应分布为原始分布,构造右截尾的车辆荷载效应概率密度函数;然后,假定抗力、恒载效应及车辆荷载效应为相互独立的随机变量,建立了考虑车辆荷载效应右截尾分布特征的限载系数反演模型;继而,通过分析车辆荷载效应均值变化对限载系数的影响规律,提出了理想抗力桥梁条件限载系数的确定方法,并讨论了条件限载系数对车辆荷载效应变异系数与分布类型的敏感程度;最后,根据原桥梁规范受弯构件承载能力设计表达式,计算了按原规范设计桥梁的条件限载系数。结果表明,桥梁限载取值仅与设计荷载等级、容许失效概率以及设计采用的活恒载比值有关,而与车辆荷载效应的统计参数关系不大。所提限载分析方法可为中、小跨径桥梁提供具有一致可靠度水平的限载取值。
[Abstract]:Based on the right truncated distribution model of vehicle load effect, a load limit analysis method for medium and small span bridges based on structural reliability theory is proposed. The probability density function of vehicle load effect is constructed with the distribution of vehicle load effect specified in the code as the original distribution, and then the resistance, dead load effect and vehicle load effect are assumed to be independent random variables. The inversion model of load limit coefficient considering the distribution characteristics of right truncation of vehicle load effect is established, and then, by analyzing the law of influence of vehicle load effect mean value change on load limit coefficient, a method of determining the load limit coefficient of bridge condition of ideal resistance is proposed. The sensitivity of conditional load limiting coefficient to the variation coefficient and distribution type of vehicle load effect is discussed. Finally, according to the design expression of bearing capacity of flexural members of the original bridge code, the conditional load limit coefficient of the bridge designed according to the original code is calculated. The results show that the bridge load limit is only related to the design load grade, the allowable failure probability and the ratio of live dead load used in the design, but not to the statistical parameters of the vehicle load effect. The proposed load limit analysis method can provide load limiting values with uniform reliability level for medium and small span bridges.
【作者单位】：山东省土木工程防灾减灾重点实验室(山东科技大学);
【基金】：山东省交通科技创新计划项目(2010Y01-2) 旧桥检测与加固技术交通行业重点实验室(北京)开放课题项目(Jqkf2011-14)
【分类号】：U441.2

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