Precast concrete arch elements provide a cost-effective design solution for small bridging and tunnel-like applications. They may bridge across rivers, roads, railways, pedestrian underpasses, stormwater channels or stockpile recovery tunnels. They may support roads, pedestrian overpasses, railways, large fills and material stockpiles. Arch elements can also be used for tunnelling purposes such as for pedestrian subways or desalination plants.
Precast arches are predominantly produced as a single arch unit or as two-piece arch units connected at the crown with either a pin or moment type connection. Arch units are installed on an insitu concrete strip footing and are placed side by side to form the structure width. They can also be purpose built in many segments to suit.
Where large expanses are to be crossed, multiple arch spans placed one after the other can provide an aesthetically pleasing structure. Complete precast concrete arch systems are available and include spandrel walls running parallel to the arch ends and wingwalls to retain the backfill at the ends and sides of the structure.