SEGMENTAL PRECAST CONCRETE POST-TENSIONED OVERPASS BRIDGES WITH CANTILEVERED ABUTMENT

摘要

A bridge structure particularly adapted for construction in skewed orientation with respect to a lower, overpassed roadway comprises a bridge portion, end abutments, and an intermediate support column. The bridge portion is constructed by supporting a plurality of precast concrete open-topped box-beams and precast L-shaped parapet-sidewalk members on temporary falsework at the bridge site. Upstanding from the precast box beams are wooden flanges which are trimmed in place to provide temporary supports of desired heights for precast slabs forming a bed for the upper roadway. The variable-height supports are used to form a crown in the roadbed, or to form an inclined roadbed which may be part of a banked curve. The precast box-beams are joined together by formed-in-place concrete diaphragms which are poured simultaneously with a concrete roadbed, whereby a monolithic squared off bridge portion is formed. An intermediate support column engages one of the diaphragms, thereby eliminating an exposed transverse support beam. The bridge portion is post tensioned by means of longitudinal and transverse post tensioned tendons.