Teruko TAKATA

3D Structural Behavior of Composite Multi - I - Girder Bridges

Masatugu NAGAI, Eiji IWASAKI

In recent years, the measure for reducing the construction cost of the bridge has been@actively taken by revival of steel-concrete composite bridges and by simplification of@structural stiffening system. However, when the bridge span is less than 30 meters or so, PC bridge has been evaluated to be economical and widely used. Hence, it is very useful@to offer more economical steel-concrete bridge solution. The composite bridge system that we propose in this study has rolled main girder and has no intermediate transverse cross beams between main girders. In order to clarify the 3D behavior of the proposed system, 3D finite element analysis under vertical loading was carried out. The concrete slab and steel girder were modeled by 20-node solid element and 8-node shell element, respectively.
The following are main findings from this study, (1)The existence of cross beam has little influence on load distribution, and it is predicted that the concrete slab plays an dominant role(2)Both longitudinal and transverse bending moment produced in the concrete slab by vehicle loading can be estimated by Japan Highway Bridge Specifications, (3)The secondary stress, which has not been taken into account at the practical design stage, is negligibly small.