Bivariate structural-fire fragility curves for simple-span overpass bridges with composite steel plate girders

•Bivariate fragility curves are developed for an overpass bridge subjected to fire.•Prototype bridge has composite steel plate girders with varying simple span lengths.•2 hazard intensity measures are used to quantify girder exposure to a tanker fire.•Max. deflection of the most-heated girder is used to determine the damage level.•Fragility curves that delineate 4 levels of damage are applied to an example.