空间三维扭曲梁预制关键技术

Key Technology of Prefabricating Spatial Three-dimensional Twisted Beam

依托宁波舟山港主通道62.5m跨径非通航孔桥,深入研究节段扭曲面无错台顺曲连接及精度控制施工技术。空间三维扭曲梁预制重点在于模板系统,既应满足刚度需要,又有一定柔度。匹配梁调节过程应保证油压装置误差精准控制在1mm,故设计可调节底模板系统,由刚性支架、调节支撑、面板、侧翼组成,采用液压小车进行底模空间姿态调整,使底模与固定端模密贴。并设计可调节外模系统,由固定外模架、可调节支撑丝杆、倒角斜拉丝杆等组成,可自上而下整体调节外模,使倒角贴合,再调节腹板丝杆,使接触面密贴,保证外腹板形成顺曲面。同时,采取台座沉降定期监测、对称分层浇筑、保护层垫块均匀布置等控制措施,使外表面曲线顺接,保护层合格率在95%以上,取得良好实施效果。

Based on the non-navigable bridge with a span of 62.5 m in the main channel of Ningbo-Zhoushan Port, the key construction technology of the non-travel connection and precision control of the segmental twisted surface is studied in depth. The prefabrication of spatial three-dimensional twisted beams focuses on the formwork system, which should not only meet the need for rigidity, but also has a certain degree of flexibility. The adjustment process of the matching beam should ensure the precise control of the oil pressure device, making sure that the error is controlled within 1 mm. Therefore, an adjustable bottom formwork system is designed, which is composed of a rigid support, an adjustment support, a panel and a side wing. And a hydraulic trolley is used to adjust the space posture of the bottom mold, making the bottom mold and the fixed end mold attach closely. Meanwhile, an adjustable outer mold system is designed, which is composed of a fixed outer mold frame, an adjustable support screw, a chamfering oblique drawing screw, etc. The outer mold is integrally adjusted from top to bottom to make the chamfer fit, and then the web screw is adjusted. The contact surface is closely attached to ensure that the outer web forms a smooth curved surface. At the same time, such control measures as regular monitoring of pedestal settlement, symmetrical layered pouring, and uniform arrangement of protective layer cushions have been taken. A total of 356 segment beams were prefabricated, and the outer surface curves were smoothly connected, and the pass rate of the protective layer was over 95%, achieving good implementation results.