In this study, static loading tests are carried out, in order to inspect behavior of improved composite slab on continuous composite girder bridges subjected to hogging moment. Main objectives of this study are to investigate crack behavior of the composite slab and to confirm the influence of the bottom plate on the resistance section of composite girder bridges. The specimens used are scale models of a continuous composite girder bridge near an intermediate support, which is subjected to hogging moment. The summaries of the experimental result are as follows; 1)The formula stipulated for RC slab in Concrete Standard of JSCE is applicable to the estimation of crack width of the composite slab. 2)The bottom plate influence should be considered using equivalent thickness proposed.
