Metal forms replace reinforcement in bridge deck slabs

Publisher Summary Research has shown that the strengths of composite concrete deck slabs of girder bridges are governed by transverse confinement, which can be provided internally in the form of bottom transverse reinforcement, or externally by means of steel straps connected to the top flanges of the girders. It is generally believed that because of the lack of bond between concrete and the galvanized surface of the metal form, the form does not participate in the load carrying action of the slab. It is shown in this chapter that with simple modifications in design, the metal form can be made to confine the deck slab transversely; the modifications comprise the provision of transverse continuity in the metal form across the bridge width. Thus, all the tensile reinforcement in the slab can be removed, except that required for transverse negative moments induced by loads on the deck slab overhangs. A full-scale model is under construction to confirm the above hypothesis. In current designs, the metal forms cease to be useful after the casting and setting of the slab, because of which, the durability of the form is of little consequence to the safety of these slabs. The same is not the case in the proposed design. It is suggested by the chapter that the problem of metal form corrosion can be solved by one of three means such as using a fiber reinforced polymer form, providing bottom transverse reinforcement, which could take over after the form has corroded, or installing steel straps when the form begins to corrode.