BRIDGE CONSTRUCTION METHOD

PROBLEM TO BE SOLVED: To construct a bridge by installing a pile foundation while reducing noise and vibration.SOLUTION: In a construction method of a bridge 1, a cross beam 4 is disposed above a steel pipe pile 2A that has been already set, and a main girder 5 on which floor slabs are arranged is connected to the cross beam 4. A movable construction truss girder 7 is moved to the front of the main girder 5 so as to protrude. The cross beam 4 is installed at a tip of the protruded movable construction truss girder 7. The main girder 5a on which new floor slabs 3a are fixed is connected to a connection member of the cross beam 4 to make a cantilever beam structure 8. A pile driver 10 is disposed on a tip of the new floor slab 3a and a rotary pile 2 that is temporarily fixed to a sheath pile of the cross beam 4 is installed by rotating and pressing in the pile underground. Although a rotational reaction applied to the pile driver 10 that rotates and installs the rotary pile 2 becomes a force to twist and deform the new floor slab 3a and the main girder 5a, the force can be suppressed by the movable construction truss girder 7 protruding on both sides. These processes are repeated to construct the bridge 1.SELECTED DRAWING: Figure 1 【課題】騒音や振動を低減させて杭基礎を打設して橋梁を構築する。【解決手段】橋梁１の構築方法は、既に設置した鋼管杭２Ａの上部に横桁４を設け、横桁４に床版３を並べた主桁５を連結してあり、その前方に移動式架設トラス桁７を移動して張り出す。張り出した移動式架設トラス桁７の先端に横桁４を取り付け、横桁４の連結部材に新たな床版３ａを固定した主桁５ａを連結して片持ち梁構造８にする。新たな床版３ａの先端に杭打機１０を配置して横桁４のさや管に仮固定した回転杭２を地中に回転圧入して打設する。回転杭２を回転して打設する杭打機１０に働く回転反力は新たな床版３ａと主桁５ａをねじり変形する力となるが、その両側に張り出した移動式架設トラス桁７によって抑えることができる。これらの工程を繰り返して橋梁１を構築する。【選択図】図１