Erection method of simple temporary bridge

A together are possible significant reduction in construction costs with available general purpose materials, to provide a construction method for simple provisional bridge that allows safe crane work the projections without having upward of the existing superstructure. A protruding ruler digits 50 A plane shape U-shape, using the 受桁 member 30 provided with a plurality of piles guide tube, and is supported in overhanging ruler digits 30 of the existing superstructure projecting ruler a first step of the digits 50 slides, a separate receiving the base end side of the overhang ruler digit 50 and a second step of fixing the existing superstructure, the front portion of the lower surface of the overhang ruler digits 50 is slidingly moved a third step of retrofitting the spar 30, and a fourth step of erected supporting pile 20 using a pile guide cylinder 32 of 受桁 material 30 was retrofitted, 受桁 member 30 located at the front end of the existing superstructure and and a fifth step of laying the main girder 40 and floor plate 41 between the 受桁 member 30 which is positioned in front of the existing superstructure, a first to fifth steps repeatedly span units. .FIELD 1