Comparison and Selection of Erection Schemes for the First Span Roadway Box Girder of Zhengzhou Huanghe River Rail-cum-Road Bridge

Restricted by the topography at the bridge site,the first span roadway box girder of the approach bridge of Zhengzhou Huanghe River Rail-cum-Road Bridge could not be erected in place by one-time transverse shifting.If the erection of other span girders was to take place prior to that of the first span girder,the overhead launching gantry,when normally stood on the pier of the first span girder,would not erect the girder to its designed position because the designed width of the pier was narrow and would make it very difficult to complete the erection of the girder.In such case,the construction schemes for erection of box girders,such as the longitudinal shifting of scaffolding,setting-up of working platform,erecting of central girder in times and longitudinal shifting of edge girders in place,were thoroughly analyzed and studied.On the basis of the comprehensive comparison,the scheme of erecting of the central girder in times and the longitudinal shifting of the edge girders was selected and the erection of the first span girder was finally smoothly realized under the condition of high-rise and narrow width pier.