| 摘要 |
A composite, prestressed structural member, such as a bridge unit and methods of forming such a member. The apparatus includes a plurality of longitudinally extending girders which are transversely spaced and a plurality of adjacent composite units disposed on the girders. Each composite unit has a plurality of beams with a molded deck portion formed thereabove. The beams are positioned transversely with respect to the girders and attached thereto. Additional, longitudinal beams are disposed between the transversely extending beams over the girders. The longitudinal beams are attached to the girders and by connectors to the molded deck. The structure is formed by positioning the girders on a construction support adjacent to a center portion of the girders such that the free ends of the girders cantilever and deflect downwardly. The beams of the composite units are attached to the girders in this construction position. Any gaps between adjacent composite units are filled with a non-shrink, high strength grout. When moved to an operating position wherein opposite ends of the girders are supported, the natural deflection of the unit due to its weight imparts a compressive prestress longitudinally in the molded deck units. Each molded deck unit may be formed such that it is also transversely prestressed.
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