基于车辆荷载效应截尾分布的桥梁限载分析方法  

ANALYTICAL APPROACH FOR DETERMINING TRUCK WEIGHT LIMITS WITH TRUNCATED DISTRIBUTIONS OF LIVE LOAD EFFECTS ON HIGHWAY BRIDGES

作　　者：李松辉[1] 

机构地区：[1]山东省土木工程防灾减灾重点实验室(山东科技大学),山东青岛266590

出　　处：《工程力学》2014年第2期117-124,共8页Engineering Mechanics

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)

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。A reliability-based analytical approach for determining the weight limits of short to medium span bridges is presented according to the right truncated distributions of live load effects. Firstly, a right truncated probability density function is derived from the original live load effect distribution specified in the current specifications. Secondly, to assume that the resistance, dead load effect and live load effect are independent of random variables, a back-calculation model for determining the weight limit coefficients is established by considering the right truncated distribution of live load effects. Thirdly, the conditional weight limit coefficients of bridges with ideal resistances are proposed by investigating the effect of mean values of live load effects on weight limit coefficients. Additionally, a sensitivity analysis is performed to further study the effect of distribution parameters and probability distribution types of live load effects. Finally, for bridges designed according to the previous bridge design specifications, the weight limits coefficients are proposed based on the design expression of the flexural member specified in specifications. The Results show that the bridge weight limits are related to the live load adopted in design, the acceptable probability of failure and the design ratios of live load to dead load, and the distribution parameters of live loads have a little effect on the final weight limits. The proposed methodology can provide a more rational truck weight limits with uniform reliability level for short to mediumspan beam bridges.

关 键 词：公路桥梁 桥梁安全 桥梁限载 可靠性分析 截尾分布 

分 类 号：U447[建筑科学—桥梁与隧道工程]