The Need
Steel-free concrete replaces reinforced concrete in bridge decks and similar structures in marine environments and in northern climates having snow and ice. It is to eliminate the source of deterioration, the steel reinforcing bars in slabs exposed to deicing salts. Eliminating corrosion makes concrete deck slabs virtually maintenance-free, which makes life cycle costs of steel-free concrete decks much lower than reinforced concrete decks.

The Technology
Shear connectors make the steel-free concrete deck composite with the steel girders that support it. Top flanges of girders attempt to displace outward when a truck drives across the deck. External transverse steel straps below the bridge deck and between the bridge girders prevent this outward displacement by providing a lateral restraining force to the girder and concrete deck. In response, compressive membrane forces develop in the concrete deck. Ultimate load can be greater than the load at which the same deck would fail if it were reinforced conventionally.