A proposition for a new construction method for cast-in-situ multi-span integral bridges

A new construction method for cast-in-situ bridges is examined. The method is proper for bridges with span lengths between 30 to 50 m. The construction of the bridge includes the following stages: Two balanced cantilevers are casted on both sides of the elevated piers. Each cantilever has a length equal to half of the corresponding span length of the bridge and is connected to the adjacent one at the mid-span. The height of the cross section of the deck is reduced from the support to the mid- span. The prestressing tendons are straight, while the reinforcements within the bottom flange of the deck consist of ordinary strength steel bars. The applicability of the proposed construction method has been examined to a real cast-in-situ box-girder bridge. Comparative results are illustrated showing that the proposed method has advantages concerning not only the constructability, but also the serviceability performance, the earthquake resistance and the structural cost of the bridge.