大跨径连续刚构桥长期下挠影响因素分析

Long Term Deflection Influencing factors Analysis of Long Span Continuous Rigid Frame Bridge

以贵都高速大跨径预应力混凝土连续刚构桥(芭茅冲大桥)为工程实例,采用有限元程序Midas/Civil对其进行施工过程和运营阶段仿真计算,分析混凝土超重、预应力损失、混凝土收缩徐变、刚度损失等因素对大跨径预应力混凝土连续刚构桥跨中长期挠度的影响。计算结果表明:混凝土超重和桥面铺装施工误差导致的自重增加均可引起桥梁跨中长期挠度增加,徐变系数、环境相对湿度的变化、预应力损失等因素对桥梁跨中长期下挠影响显著;梁体刚度降低跨中长期挠度增加较多,且早期刚度的降低对桥梁跨中挠度增加影响较大。

A case study of a large span prestressed concrete continuous rigid frame bridge （ Ba Mao Chong bridge） of GUI DU high speed railway was studied. Finite element program midas/civil was used to simulate the construction process and operation phase, the influence of concrete overweight, prestressing loss, concrete shrinkage and creep, stiffness loss and other factors on the long-term deflection of long span prestressed concrete continuous rigid frame bridge was analyzed. The calculation results show that the weight leading to overweight and concrete bridge deck pavement construction error increase can cause the bridge long-term deflection increases, the creep coefficient, the change of relative humidity of environment, and other factors on the bridge prestress loss significantly long-term midspan deflection effect;beam stiffness reduces with the increases of long-term midspan deflection. The decrease of beam stiffness has a great impact on the bridge deflection in the early period.