Through girder bridge widening system - uses replacement frame erected by cantilevering laterally from existing superstructure

摘要

An existing through girder bridge of steel or concrete construction is widened by cantilevering laterally from the existing superstructure without disturbing the substructure. A replacement frame is used which resists the dead and live loads applicable to the modified form of bridge. Steel structurs may be modified by adapting the existing transverse deck members, these members being completely renewed in the reinforced concrete case. Single bridges may have equal width cantilevers on each side, double bridges being widened by cross connection. The existing longitudinal lattice girders on each side may be removed once the new frame is erected.