PRESTRESSED COMPOSITE BEAM CARRIED IN ENTIRE COMPOSITION BY UNIFICATION OF LOWER CASING CONCRETE AND REINFORCEMENT OR STEEL WIRE AND MANUFACTURING METHOD THEREOF

摘要

PURPOSE: A manufacturing method for a prestressed composite beam placed by composing lower casing concrete and a reinforcing bar or a steel wire in one is provided to maximize the compressive stress on concrete by minimizing a loss of compressive force of a prestressed concrete beam in a releasing progress and to form a section resisting a crack. CONSTITUTION: The manufacturing method for a prestressed composite beam placed by composing lower casing concrete(20) and a reinforcing bar or a steel wire(30) in one comprises the steps of: manufacturing a steel girder(10) cambered upward; adding preflex load(P) on the steel girder(10) to be bent downward; installing inner/outer pressure plates on both ends of a lower flange of the steel girder(10); installing a reinforcing bar or a steel wire(30) on a lower flange of the steel girder(10) by letting a reinforcing bar or a steel wire(30) through the inner/outer pressure plates; anchoring a reinforcing bar or a steel wire(30) on the outer pressure plate using a coupler; placing tensile force on the reinforcing bar or the steel wire(30) arranged on the lower flange by installing a jack between the inner/outer pressure plates, then pushing to both sides; anchoring a reinforcing bar or a steel wire(30) on the inner pressure plate using a coupler to keep tensile force, then removing the reinforcing bars or the steel wires(30) between the outer pressure plate and the inner pressure plate; and placing lower casing concrete(20) on the lower flange of the steel girder(10) and removing preflex load gradually after curing the concrete surface, then placing and curing concrete on an upper flange of the steel girder(10).