Revival of Composite Girder Bridges and Developement and Research of Composite Structures
Caused by many reports on deterioration of reinforced concrete slabs on steel bridges, construction of composite girder bridges has decreased remarkably in the re cent two decades. But, the composite girder bridge seems to be supeior system even though it has RC slabs on it. The author is strongly expecting revival of the construction of composite girder bridges because an improvement of durability of RC slab is possible. In the development works of composite structures, experimental studies are carried out to verify the structural behaviors and strength. Some experiments in the works, however, seem to be unappropriate to discuss the actual behavior due to unreasonable selection of test specimens. Systematic plan of experimental tests should be built. when durability of a slab structures is investigated by fatigue testing, genaraly a pul sating load is applied. But, the author uses a wheel running machine because the actual slab is subjected to running wheels. By the two methods, the fatigue failure modes are quite different mutually even for the same specimens. Therefore, it should be recommended that an adequate testing machine has to be selected corresponding to the actual loading pattern on the structures.