【摘要】 针对采用节段悬浇施工的大跨度混凝土梁桥普遍存在的持续下挠问题,提出基于荷载效应平衡的"合理成桥状态"概念以及相应的预应力配筋设计方法。通过合理的纵向预应力配置去适度平衡多种作用效应,使桥梁处于合理的成桥状态(弯曲状态、应力状态和挠曲状态),以便能够抑制跨中长期下挠。此外,还提出控制最大压应力水平和采用体内-体外混合配束的设计策略。结合持续下挠的机理讨论,认为合理成桥状态是一种能有效抑制桥梁下挠的实用设计方法。更多还原

【Abstract】 In the light of the sustained defection deterioration commonly existing in the long span prestressed concrete(PC) girder bridges constructed by the segmental cantilever casting method,the concept of the "rational completion status" based on the load effect balancing principle and the corresponding design method for arrangement of prestressing are proposed.By way of the rational arrangement of the longitudinal prestressing,the different actions of various effect will be balanced to an appropriate degree and the bridges will be kept in the rational completion status(bending status,stress status and flexure status) so that the middle and long term deflection of the bridges can be inhibited.In addition,the design strategy of controlling the maximum compressive stress level and the mixed arrangement of the internal and external prestressing is also put forward.With reference to the discussions on the mechanism of the sustained deflection,the "rational completion status" concept as provided herewith is justified as a practical design method that can effectively inhibit the sustained defection of the bridges.更多还原