Random Differential Settlement Effects on Reliability of Existed Bridges
This paper investigates the impact of differential foundation settlement on the reliabihty of bridge super structure based on loads and resistances statistical properties in Missouri State.Maximum deterministic dif ferential settlement is often used in current AASHTO LRFD design specification.However, the expected foundation settlement is quite different than the actual settlement due to the soils large variability.There fore, it makes sense to consider settlement as a random variable.In this paper, a lognormal distribution with coefficient of variation of 0.25 of random settlement is considered in rehability analysis based on limited pre vious studies.Dead and live loads are modeled as random variables with normal and Gumbel Type I distribu tions, respectively.Considering the regional traffic condition on Missouri roadways, the live load effect on existed bridges based on weight-in-motion data is also investigated.The calibrated resistance statistical prop erties such as bias and coefficient of variance are used for reliability analysis.Total 14 existing bridges based on Strength I Limit State are analyzed.Since no differential settlement is considered in the past designed bridges in Missouri, small differential settlement can significantly reduce the reliability indices of the super structure, depending upon the span length and rigidity of the girder.The analysis results also show that the reliability of existing steel-girder bridges is consistently higher than prestressed concrete and solid slab bridg es; the shorter and stiffer the spans, the more significant the settlements effect on the reliability of bridge superstructures ; As the span length ratio becomes less than 0.75, the girder and solid slab bridges reliabili ty drops significantly at small settlements.
Zuocai Wang Genda Chen Weixin Ren
Department of Civil Engineering, Hefei University of Technology, Hefei, China Department of Civil, Architectural, and Environmental Engineering, Missouri University of Science an
国际会议
哈尔滨
英文
702-709
2013-07-06（万方平台首次上网日期，不代表论文的发表时间）