Abstract: A trussed structure includes at least a pair of parallel trussed girders. In one of the trussed girders, an upper chord member and a lower chord member are joined through lattice members. The trussed structure includes at least a pair of prestressing members spanning between the opposite sides of the trussed structure. The central portions of the prestressing members are disposed below the end portions of the prestressing members, and connected to the lower chord members so as to pull the lower chord members upwardly. The central portions of both of the prestressing members are disposed between the adjacent trussed girders.

Abstract: A trussed girder to be positioned between a pair of columns, the trussed girder comprising:a pair of upper chord members disposed generally parallel to each other in a horizontal plane;a lower chord member disposed beneath the upper chord members to form a triangular cross-section so that three vertices are formed by the upper chord members and the lower chord member;a pre-tension member extending generally longitudinally within the triangular space;whereby a compressive force is exerted on the lower chord member as tension is exerted on the pre-tension member.