Experimental and theoretical studies of composite multiple-box girder bridges

Due to their high torsional and wrapping stiffness as well as economic and aesthetic reasons, multi spine composite concrete-deck steel-box girder bridges became a very popular choice in highway bridges. Currently, North American Codes of Practice have recommended some analytical methods for the design of curved multiple-box girder bridges, providing a geometrically defined criterion to establish when horizontally curved may be treated as a straight bridge. To meet the practical requirements arising during the design process, a simple design method is needed for straight and curved composite box girder bridges in the form of load distribution factors. This study consisted of an experimental and a theoretical investigation. The experimental investigation included testing up-to-collapse three bridge models. While the theoretical investigation used a finite element software to examine the behavior of 225 different bridges to extract stress distribution factors for maximum bending stresses that occur at the mid span.