预应力混凝土连续箱梁桥悬臂施工挂篮预压试验研究

Experimental Study on the Techniques of Hanging Basket Prepressing in the Cantilever Construction of Prestressed Concrete Continuous Box-girder Bridge

结合沁河大桥工程监控方案,针对预应力混凝土连续箱梁桥悬臂浇筑的施工特点,进行了挂篮静载预压试验.经验证:挂篮结构能够满足施工安全需要;挂篮静载预压能消除挂篮结构因拼装引起的非弹性变形.通过对挂篮预压结果与浇筑混凝土后相应块的数据对比分析,发现同一块段预压与浇筑后的沉降变形一致.分析挂篮弹性变形与预压荷载的关系曲线,发现挂篮预压与浇筑后块段弹性变形存在线性关系.对弹性变形数据进行线性拟合,得出弹性变形与预压荷载的线性关系方程式,可为预应力混凝土连续箱梁的悬臂浇筑线型控制提供依据.

Combining with the monitoring scheme of Qinhe Bridge Project, and in view of the construction characteristics of the cantilever pouring of prestressed concrete continuous box-girder bridge, the static-load prepressing test was carried out. The experimental results verify that the hanging basket structure meets the need of the construction safety, static-load prepressing of the hanging basket can eliminate the inelastic deformation caused by the structure assembling. Comparing and analyzing the result from the prepressed experiment of the hanging basket with the data of the corresponding block after pouring concrete, the settlement deformation after prepressing is consistent with that after pouring. Analyzing the relational curve between the elastic deformation and the prepressed loads for the hanging basket, it is found that a linear relation exists between the prepressed loads for the hanging basket and the elastic deformation of pouring block. The data of the elastic deformation are linearly fitted, the relation equations between the elastic deformation and prepressed loads are established. These conclusions provide some basis for linear control of the cantilever pouring of prestressed concrete continuous box-girder bridge.