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针对悬浇混凝土连续梁桥合龙段顶板纵向开裂这一常见质量问题,探讨了合龙段两侧约束对顶板横向应力的影响。考虑合龙段两侧的实际约束状况,提出了合龙段的横向预应力作用分析模型和早期收缩分析模型。结合实例,分析了受相邻梁段影响的合龙段横向预压应力折减,以及龄期差异引起的横向拉应力。研究表明,采用一种优化的合龙段横向预应力张拉方案,并同时减少合龙段混凝土收缩,可以有效地改善顶板的抗裂性。
Aiming at the common quality problem of the longitudinal cracking of the roof of a cantilevered concrete continuous girder bridge, the influence of the constraint on both sides of the roof is discussed. Taking into account the actual constraints on both sides of the closure segment, a transverse prestressing analysis model and an early shrinkage analysis model of the closure segment are proposed. In combination with the example, the transverse prestressing stress reduction of the closing section and the transverse tensile stress caused by the difference of age are analyzed. The research shows that adopting an optimized transverse prestressing tensioning section and reducing the shrinkage of the concrete in the closing section can effectively improve the crack resistance of the roofing slab.