大跨径PC连续刚构桥施工控制参数敏感性分析

大跨径PC连续刚构桥施工控制参数的变化往往会改变结构的线形与应力状态，从而影响桥梁的合龙精度与最终成桥状态的结构内力。为研究施工控制参数的敏感性，本文以巴河大桥为工程背景，结合有限元方法，借助仿真计算软件，分析主梁悬臂施工过程中材料容重、结构刚度、预应力损失、混凝土收缩徐变、温度、基础沉降等6大主要参数对桥梁结构线形和应力的影响。结果表明:混凝土容重增大会加大主梁下挠，而对梁截面应力无明显影响；预应力损失对主梁的线形影响最大，当预应力损失达到20%时，主梁最大挠度将增加250%；混凝土收缩徐变、环境温度对跨中线形影响最大，而对0#块根部影响较小；基础不均匀沉降对结构的线形影响呈抛物线形式分布，各参数对主梁挠度的影响大于对梁截面应力的影响。

Sensitivity Analysis of Construction Control Parameters of LongSpan PC Continuous Rigid Frame Bridge

The variation of construction control parameters of long-span PC continuous rigid frame bridge will often change the linear and stress state of the structure, thus affecting the precision of the bridge and the structural internal force of the final bridge state. In order to study the sensitivity of construction control parameters, the Bahe bridge was used as the engineering background, combined with the finite element method, and the simulation calculation software is utilized to analyze the influence of the material bulk density, structural stiffness, prestress loss, concrete shrinkage and creep, temperature during the cantilever construction process on the linear shape and stress of the bridge structure. The results show that increasing the bulk density of the concrete will increase the deflection of the beam, but has no significant effect on the beam stress. The prestress loss has the greatest influence on the linear shape of the main beam. When the prestress loss reaches 20%, the maximum deflection of the main beam will increase by 250%. Shrinkage and creep of concrete, ambient temperature have the greatest influence on the mid-line shape, and have less influence on the root of 0# block. The uneven shape of the foundation has a parabolic distribution on the linear shape of the structure. The influence of each parameter on the deflection of the main beam is greater than the stress on the beam section.