Fatigue life of girders with trapezoidal corrugated webs

Fatigue design criteria are necessary to design steel corrugated web girders, for highway bridges. The paper presents research on the fatigue life of steel bridge I-girders with trapezoidal web corrugations. Eight large-scale test girders were fabricated from HPS 485W steel and fatigue-tested in four-point bending. The web-to-flange fillet welds were made using semiautomatic gas metal arc welding (GMAW) or robotic GMAW. Fatigue cracks initiated in the tension flange at the web-to-flange fillet weld toe along the inclined web folds and adjacent bend regions, and propagated in the flange. The results demonstrate that steel corrugated web I-girders exhibit a fatigue life that is longer than that of conventional steel I-girders with transverse stiffeners. For design of corrugated web I-girders, the Category B' design curve of the AASHTO LRFD specifications is recommended for finite life fatigue design calculations, and a value of 96.5 MPa (14.0 ksi) is recommended for the constant amplitude fatigue limit.