Estimation of punching shear fatigue strength for steel plate-concrete composite decks

In Japan a steel plate-concrete composite deck, i.e. concrete connected to steel base plates with shear studs, is called a Robinson-type deck. In order to decrease the deflection of the steel base plate due to the weight of the concrete, the steel base plate is stiffened with steel lateral ribs. In recent years the composite deck has been used for many highway bridge decks, such as steel twin-girder bridges, open-section steel box girder bridges, etc. Its predominant failure mode was discovered to be punching shear failure by repetition of wheel loads. In this paper the authors derive the estimation formula for the punching shear fatigue strength of the composite deck from the results of wheel trucking tests. Furthermore, the relationship between the non-dimensional strength ratio of an applied load divided by the punching shear strength and the number of cycles until failure was confirmed and plotted on the S-N curve for an RC slab. Therefore, the fatigue design of the composite deck can be executed reasonably with the S-N curve.