Answer :
After calculating the anticipated traffic for the bridge, cement/reinforced- with- rebar stanchions
are spaced over the freeway to accommodate the bridge. An ‘off-ramp’ from the freeway to the
bridge is constructed, as is an ‘on-ramp’ to the subsequent road. Cement/rebar slabs are built
and lifted with cranes to form the platform, and voila! Drive carefully.
Although the bridge deck/roadway is almost always a concrete slab, the structure that holds up
the bridge deck can be reinforced concrete, structural steel, or a combination of steel and
concrete.