节段预制拼装箱梁多节段悬拼创新设计

Innovative Design of Multi-Segment Cantilever Assembly for Precast Segmental Box Beams

摘要:

为提高某跨海桥梁海中节段预制拼装箱梁施工效率和精度，控制关键线路工期，首次提出多节段悬臂拼装技术。结合项目实际情况，通过改进体内预应力布置，比选多节段架设组合方案，创新性提出了节段梁“2+3+2”多节段悬拼方案。运用空间杆系有限元模型，依据现行规范开展全面受力验算，结果表明：桥梁各工况（持久、短暂）的承载力、抗裂、应力及挠度均满足规范要求。实际施工过程验证了设计方案的高效性和便利性，关键线路节约工期约5个月。该设计对同类市政、公路节段梁项目具有推广使用价值。

Abstract:

To improve the construction efficiency and precision of precast segmental box beams in the offshore section of a cross-sea bridge and control the construction period of the critical line, a multi-segment cantilever assembly technology is proposed for the first time in the design. Combined with the actual project conditions, through the improvement of internal prestress layout, and the comparison and selection of multi-segment erection combination schemes, an innovative "2+3+2" multi-segment cantilever assembly scheme for segmental beams is put forward. A spatial bar system finite element model is adopted to conduct a comprehensive stress checking calculation in accordance with current codes. The results show that the bearing capacity, crack resistance, stress and deflection of the bridge under various working conditions (persistent and transient conditions) all meet the code requirements. The actual construction process verifies the high efficiency and convenience of this design scheme, which saves approximately 5 months of construction time on the critical lines. This design has popularization and application value for similar municipal and highway segmental beam projects.