Q: How can I get the grid reinforced concrete deck to act compositely with the girders? A: By attachment of the grid reinforced concrete bridge deck to the supporting elements via headed shear studs, the deck will naturally act compositely with the superstructure. The BGFMA recommends at least one 0.75” diameter stud, at 8 to 12 inch spacing along the supporting element, located between main bearing bars for any deck. If the design is composite however, the designer must specify the required diameter and number of studs. Make the shear stud spacing consistent with the grid main bar spacing.