| 摘要 |
The present invention is to prevent structural damage of splitting by installing an upper pit of an end of a girder and an upper pit of an end of a joint girder at both ends of a unit girder in the shape of an opening, opened toward a longitudinal direction from the end of the girder, and installing a fixture of a secondary steel wire at a position at the end of the pit, i.e., at a position outside a primary steel wire mounting mono block region, so that splitting tension is not applied to the primary steel wire mounting mono block receiving the splitting tension. Also, by adjusting the height of the secondary steel wire in the opened opening and a space of a bottom plate slab on the opened opening when a bridge of the girder is constructed, the maximum tension of the upper end of the joint girder, to which the maximum negative moment is applied when live load is applied, can be resisted, due to the proper eccentric distance (e), and the structural performance of the decreased girder section and the continuation of the girder can be improved by minimizing the tension applied to the lower end of the joint girder when the secondary steel wire is tensioned. A falling prevention support steel is fixed to the cross pit by an anchor bolt to prevent the girder from falling down until a falling prevention beam is deposited and cured after the unit girder is placed on a pier. Since the secondary tensioning and fixing work is performed on the bottom plate slab through the opening of the bottom plate slab after the unit girder and the bottom plate slab are constructed, it is possible to easily and effectively perform the tensioning and fixing work of the secondary steel wire in a safe manner. |
