CONSTRUCTION METHOD FOR A STEEL BOX CONTINUOUS BRIDGE USING A NEGATIVE MOMENT REDUCTION SYSTEM INSTALLED IN A STEEL BOX GIRDER TO REDUCE THE MAGNITUDE OF NEGATIVE MOMENT OCCURRED ON A CONTINUOUS SUPPORTING POINT IN A STEEL BOX CONTINUOUS BRIDGE FOR THE ECONOMICAL AND EFFECTIVE MANAGEMENT OF A BRIDGE

摘要

PURPOSE: A construction method for a steel box continuous bridge using a negative moment reduction system is provided to manage a bridge economically and effectively by decreasing the height of a girder, extending a span effective span and reducing the quantity of steel required for a girder by reducing the negative moment applied on a steel box girder. CONSTITUTION: The construction method for a steel box continuous bridge using a negative moment reduction system(20) comprises the steps of: installing vertical and horizontal ribs(29,21) on inner lower flanges(13) in a steel box girder(10), installing stud bolts(33) at regular intervals and assembling reinforcing bars(31); welding a double flange(28) on the horizontal rib(21); placing concrete(32) between the double flange(28) and the inner lower flange(13) and filling up a space with epoxy(30); installing supports(25) on both vertical ends of the double flange(28) installed on the inner lower flange(13), installing an anchorage bracket(23) on both upper parts of the double flange(28) to be adjacent to the support(25) and installing an auxiliary anchorage bracket(26) to the middle part where the anchorage bracket(23) is installed; perforating holes on a partition(16) installed in the steel box girder(10), then placing and fixing a steel bar(27-1) to the anchorage bracket(23) and the auxiliary anchorage bracket(26); installing an anchorage bracket(23) on an outer upper flange(11) in the steel box girder(10) and connecting to an anchorage(24) using a steel bar or a strand(27); installing vertical and horizontal ribs(29,21) on an inner upper flange(12), welding a double flange(28) on the horizontal rib, installing supports(25) on both vertical ends of the double flange(28) and installing an anchorage bracket(23) on the double flange(28) to be adjacent to the support(25); perforating holes on the partition(16) installed to the inside of the steel box girder(10), then placing a steel bar or a strand(27) and connecting to the anchorage bracket(23); after applying tensile strength on the steel bar or the strand(27) installed on the inner and outer upper flanges(12,11), installing a steel box girder fixed with a negative moment reduction system(20) using an anchorage(24) on a continuous supporting point of a pier.