Arch Method of Bridge Construction:
The arch is the most natural bridge shape in nature. Originally constructed of stone, today such bridges are built of reinforced or precast concrete. They are often the most economical choice where a bridge is required to cross over inaccessible landscapes.
The development of modern arch construction methods has made the use of arch construction more economical by removing the need of expensive centring formwork. Though abutments still must be well founded on rock or soild ground.
Two construction techniques are most commonly used today.
(i) Cast-in-situ free cantilever method
This method involves the partially built arch tied back to rock anchors in the valley side slopes.
(ii) Slip formed sections
This method involves half arch sections being held vertically over each abutment and then rotating each arch section into position.
Tee-beams are generally used for arch bridge decks for their functionality and self weight.