THE INVESTIGATION OF FATIGUE EFFECT OF LOAD-INDUCED IN STEEL GIRDER BRIDGES

Abstract

Fatigue is an important design state affecting the safety of the structure. Due to the cyclical effect of vehicleload, fatigue-induced structural cracks occur in the connection details of steel girders. If the necessary measuresare not taken against these cracks; the cracks grow and as a result the structural elements become unstable, it cannot carry the internal forces and lose their function. The AASHTO Bridge Design Specification classifies fatigueas load- dependent and distortion-dependent in steel girder bridges and in order to ensure fatigue safety, it isaimed to prevent or minimize the formation of cracks in structural elements. In load-induced fatigueinvestigation; load and stress limits are taken into account in structural elements to prevent fatigue cracks andfatigue safety is checked for the appropriate connection detail category. In this study, a three-span steel girderbridge was analyzed under fatigue loads with CSiBridge package program. In the analysis, fatigue designproperties of AASHTO Specification were used. According to the results of the analysis, it has been proved thatthe structure is safe from fatigue considering the appropriate fatigue category.