the end post of bridge supports the axial girder of bridge chair. The axial girder is divided into three sections. While erecting single-row bridge, the end post of truss supports the middle section of axial girder; while erecting dual-row bridge, using two bridge chairs, the end post supports respectively the middle section of the two axial girders of bridge chair; while erecting triple-row bridge, using still two bridge chairs, the end post of internal row supports the