预应力混凝土连续弯箱梁桥同步顶升纠扭施工

既有预应力混凝土连续弯箱梁桥在运营阶段经常出现支座变形、脱空及梁体扭转、偏位等病害,使桥梁结构受力趋于不利状态。以上海市一座匝道桥梁加固处理为对象,在对该桥病害原因进行分析的基础上,介绍采用PLC液压同步技术对桥梁进行整体同步顶升(不对称布顶)更换支座、纠扭、增设支座调整扭矩与支座反力等改造措施。实施结果表明:同步顶升控制系统较好地保证了顶升位移的精度;支座反力测定简便、可靠;病害弯桥基本恢复到原设计状态,实施效果良好。

Torsion Correction in Synchronous Jack-up Construction of Prestressed Concrete Continuous Curved Box Girder Bridge

The existing prestressed concrete continuous curved box girder bridge often suffers from bearing deformation,bearing hanging in the air,girder torsion and offsetting in operation stage,and the mechanical behavior of bridge structure tends to be in unfavorable condition.The strengthening of an interchange in Shanghai was taken as study object.Based on the analysis of the causes leading to those damages,the PLC hydraulic synchronization technique was applied to carry out the overall and synchronous jacking up and a series of improvement measures of changing bearings,correcting torsion,adding bearing tuning torsion and testing the bearing reaction force.The results of the strengthening indicate that the synchronous jack-up control system well guarantees the accuracy of the jack-up displacement;the testing of the bearing reaction force is simple and reliable;the deteriorating curved bridge is basically restored to its original design condition,and the strengthening effect is sound.