%0 Generic
%9 Master's Thesis
%A Kacin, Jennifer Ann
%D 2009
%F pittir:6513
%K sign structure modeling; stress-life
%T Fatigue Life Estimation of a Highway Sign Structure
%U http://d-scholarship-dev.library.pitt.edu/6513/
%X Sign structures stand along every highway and interstate across the country in order to guide motorists to their destination. Such structures are repeatedly subjected to natural wind gusts and gusts from vehicles passing underneath. Over time, the members within the structure may begin to succumb to fatigue due to this cyclical loading, in the form of cracks in the members and in the connections. The goal of this project is to determine the fatigue life of an overhead four-chord truss sign structure located in Pennsylvania in both a damaged and undamaged state. A finite element model of the structure was made using commercial software and a time varying natural wind load was applied to it. The stress history of critical elements was then extracted from the model's solution. Complete stress cycles were counted and then a linear damage accumulation method was used in order to find the fatigue life in the critical members. The non-damaged structure's critical members were found to have an infinite fatigue, as were the damaged structure's critical members. Despite this, members with welded connections should still be closely monitored during inspection because they have the highest potential for failure.