Precast or in-situ construction
Few bridge decks can be poured in a single operation. Most are constructed in stages, with the decks generally formed from elements by dividing them either longitudinally into beams or transversely into segments. Some very wide structures may be divided in both directions. Other methods can include working with larger elements for the construction of full spans.
Bridge elements are either precast before erection or cast in their final position. There are different methods available for activating the bridge deck’s structural performance progressively so that it becomes self-supporting.
The precast elements are usually erected using specialist equipment adapted to suit the method of construction. They are then secured together using post-tensioning.