Abstract
Under heavy traffic condition, some fatigue cracks have been found at welding joint between U-shaped ribs “trough ribs” and deckplate. In Japan, these plate thicknesses are specified in the fatigue design guideline for highway bridges, and these combination are limited. So, we conducted fixed-points fatigue tests with real scale partial specimens consisted with two trough ribs and a transverse girder, and the elastic FEM analysis for these fatigue tests. Based on these results, we studied on the characteristics of the fatigue cracks focused on plate thickness. Among these studies, we proposed “the variation of synthetic strain”, which is the synthesis of amplitude of strains in 3-deirections, as a quantitative indicator for evaluation of durability of such welding joints.
