Punching Strength of Deck Slabs in Skew Composite Bridges

Abstract

During the last few decades, composite steel-concrete structures have been used widely to form the basic superstructure for numerous bridges. Proper design of the deck slab for such bridges requires a proper estimate of their punching strength. Current codes of practice do not take into account the influence of skew and other factors on the punching strength of deck slabs in skew composite bridges. One code of practice suggested, but without substantiation, that for deck slabs in bridges with skews exceeding 20°, a reinforcement ratio of 0.6% should be used in the end portions near the supports. In this paper, the influence of several factors on the punching strength of deck slabs of skew composite steel-concrete bridges is examined. These factors include: reinforcement ratio, angle of skew, deck thickness, load position, shear connectors, size and spacing of longitudinal girders, and cross-bracing. An experimental study was conducted on seven simply supported skew composite steel-concrete bridge models to verify the analytical nonlinear finite-element solution. Based on a parametric study a formula is proposed, which permits the calculation of the punching strength of deck slabs in skew composite steel-concrete bridges, accounting for the various influencing factors.