The Hanjiang River Bridge in Yunxian County is an earth-anchored prestressed concrete cable-stayed bridge with span arrangement of (86+414+86) m.Four axle-load-free intermediate hinges, which can move longitudinally and transmit shearing force and bending moment of the bridge, are installed.Due to the cable force variation, creek and shrinkage of the structure and the wind and rain induced vibration of the bridge, the axle-load-free intermediate hinges had slid towards one side, as a result, the hinges were stuck at one end and could only move at the other end.To reposition the axle-load-free intermediate hinges and make them maintain the condition of free sliding at two ends, three maintenance schemes of adding external forces, temperature difference displacement method and adding external force after the elevation adjustment were proposed, through deterioration condition and offsetting investigation of the axle-load-free intermediate hinges as well as their working condition.The scheme of adding external force was chosen.Reaction force frames were installed at the steel box ends of the axle-load-free intermediate hinges and were rigidly connected with the steel boxes.When the reaction force frames began to carry loads, the steel boxes were dragged by the rigid connection, and successfully dragged the four axle-load-free intermediate hinges to the design position.%郧县汉江大桥为(86+414+86) m地锚式预应力混凝土斜拉桥,跨中设置4个无轴力中间铰(4个闭合钢箱),无轴力中间铰可以纵向滑移,同时传递桥梁剪力与弯矩.由于运营过程中索力变化、结构自身收缩徐变和桥梁风雨活荷载振动,无轴力中间铰往一端滑移后导致其发生一端卡死、一端可滑移的现象.为了使无轴力中间铰归位并保持两端可自由滑移的工作状态,通过病害情况调查,根据无轴力中间铰钢箱偏移调查结果,结合其工作情况,拟定了施加外力法、温差位移法和调整标高后施加外力法3种维修方案.该桥按照施加外力法方案,在无轴力中间铰钢箱端头安装反力架,反力架与钢箱刚接,利用千斤顶顶推反力架,反力架受力后通过刚性连接拖拉钢箱,成功将4个无轴力中间铰钢箱拖拉至设计位置.
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