Experimental Investigation of Non-composite and Composite Deck Bridges

Abstract

Use of composite RCC deck over steel bridges has now significantly increased. The detailed experimental study was conducted to ascertain improvements due to composite RCC deck over non-composite bridge model. Deck type steel bridge models, with and without composite decks were tested in laboratory up to failure. The failure in non-composite model was observed due to buckling of top chord member at a stress of 234.6 N/mm2, whereas for the model with composite deck it changed to rupture of the bottom chord in tension at a stress of 614.8 N/mm2. Failure load and stiffness of the structure also increased significantly due to the composite action. Shear connectors designed as per IRC 22:2008 transferred the shear effectively and deck slab also participated in load sharing. Further, load sharing in the top chord compression member comprising the steel top chord, the concrete in the deck slab, and the reinforcing steel in it, was also explored. It is found that 72.0% of the composite top chord compressive force is taken by the RCC deck, and in the RCC deck 30.7% force is taken by the reinforcement. Strain variation in deck slab was also recorded using strain gauges. Strain in deck slab over top chord members was observed to be 54% more than the strain in the middle of the deck slab.