Abstract
In this paper, the safety to overall lateral-torsional buckling and the lateral-torsional buckling of the main girders between the cross girders is examined for the erection of the steel twin girder bridges before the concrete slab is harden. Using the elasto-plastic finite displacement analysis to the structural system under erection, which have changed distance of main girders, or cross girders. To the lateral-torsional buckling, the proper parameters are established and the relation between the buckling strength and parameters are considered. And, the safety to initial deflection, the lateral-torsional buckling and the reaction force is examined in the case of the incremental launching method.
