Masaki FUJIMOTO

3D structural characteristics of skewed composite rolled H-girder bridges without intermediate cross beams

Masatugu NAGAI, Eiji IWASAKI

Based on an economical evaluation done by Japan Highway Public Corporation (JH), when a span length is less than 30 meters, it has been reported that RC or PC bridges are the most economical solution. As a competitive counterpart against RC or PC bridge solutions, we proposed a composite rolled H-girder bridge without intermediate cross beams and lower lateral bracing members. It is a very simple bridge system, however, removing the above members violates provisions stipulated in Japan Highway Bridge Specifications (JHBS). Hence, using 3D finite element analysis, in which the concrete slab and steel plate are modeled by solid and shell elements, the structural characteristic has been made clear. From the calculation, due to the difference of deflection of each main girder, even though the transverse bending moment in the slab under T-loading exceeds the design values stipulated in JHBS, no problems have been revealed. Finally, on condition that we carefully design the slab, we came to the conclusion that the proposed new bridge system is applicable.
The main aim of this study is to identify whether or not the proposed system can be used for skewed bridges. Selecting skew angles as a design parameter, 3D finite element has been carried out. From the calculations, it was found, though the transverse bending moment increased depending on the skew angle, the magnitude was not so large. It is concluded that the proposed system can be applied to skew bridges.