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目前,预应力连续刚构广泛应用于桥梁建设中,是跨越河流、道路时主要的桥式方案之一,具有跨越能力大,整体性较好、外观简洁等优点,且施工工艺成熟、简便。然而,在运营过程中,部分大跨度连续刚构预应力摩阻损失过大,预应力储备不足,直接导致主跨下扰过大、梁体腹板出现细裂缝等问题。本文论述预应力摩阻损失的成因,结合实例阐述μ、k系数对挠度的敏感性及预应力摩阻损失对跨中挠度的影响,为连续刚构设计提供一定的经验。
At present, prestressed continuous rigid frame is widely used in bridge construction. It is one of the major bridge schemes when crossing rivers and roads. It has the advantages of large span capability, good integrity and simple appearance, and the construction technology is mature and simple. However, in the course of operation, the prestressed friction loss of some long-span continuous rigid frames is too large, and the prestressed reserves are not enough, which leads to the problems of large disturbance of the main span and thin cracks in the web of the beam. In this paper, the causes of prestress friction loss are discussed. The sensitivity of μ and k coefficient to deflection and the influence of prestress friction loss on midspan deflection are expounded with examples to provide some experiences for continuous rigid frame design.