Field investigation of out-of-plane deviations for steel box girder bridges

The degree of geometrical imperfections existing in the plate panels of six in situ steel box girder bridges located throughout Canada is reported. The purpose of a continuing investigation is to establish the extent to which strength and performance of Canadian box girders in multispan bridges are sensitive to imperfections. The 95% fractiles obtained from the imperfection measurements of webs and bottom flanges are shown to vary considerably from one bridge to another but, in general, tend to decrease with increasing plate thickness. Key words: bridges (box girder), field measurements, geometric imperfections, plate panels, structural steel.