Composite Action

Filled and partially filled grid decks, and grid decks composite with a reinforced concrete slab can be made composite with steel superstructures by welding shear studs to the supporting structural components and embedding the shear studs in a haunch area with full depth concrete. This haunch area is placed at the same time as the reinforced concrete is placed when the concrete is cast-in-place, or separately when the reinforced concrete is precast. In order to assume composite action between the supporting components and the metal grid deck, the shear studs must be designed and placed in accordance with Article 6.10.10 of the AASHTO LRFD (7th Edition, 2014). If these deck types are considered to be composite with the main supporting components, an effective width of slab can be assumed for the design of the main supporting components. The slab effective width is to be computed in accordance with Article 4.6.2.6.1 of the AASHTO LRFD (7th Edition, 2014). For the design of the main supporting components, the section properties should be computed omitting any effect of the concrete slab in tension.