铁路斜拉桥钢混结合段的收缩徐变行为分析

Time-dependent Creep and Shrinkage Analysis of Steel-concrete Composite Segment of Cable-stayed Railway Bridge

基于甬江特大铁路斜拉桥工程,运用Fortran语言对Ansys有限元软件进行二次开发,数值模拟出核心混凝土的收缩徐变作用,并在此基础上深入研究收缩徐变对钢混结合段应力分布规律和传力机制的影响;提出了承压板传力率、钢混结合段传力斜率、钢混结合段传力不均匀度等衡量钢混结合段传力性能的指标,并评价了收缩徐变对钢混结合段受力行为的影响。研究结果表明:考虑混凝土收缩后钢结构应力增大1倍,混凝土应力减小1/2;考虑3年徐变后,钢壳体应力为瞬时应力的1.9~2.47倍,混凝土应力为瞬时应力的0.13倍;收缩、徐变作用均改变了钢混结合段的传力模式,考虑收缩、徐变后传力不均匀度分别增加了0.13、0.44,钢混结合段端部剪力连接件剪力最大增长幅度分别为75%、150%。

Based on the Yongjiang river extra-long cable-stayed railway bridge project,the force condition and force transmission performance of the steel-concrete composite segment under the shrinkage and creep of the core concrete were calculated by using the Ansys software of secondary development based on the Fortran language.The force transfer rate of the pressure plate,the slope of the combined force and the nonuniformity were proposed to measure the force transmission performance of steel-concrete composite segment,and these indexes were used to evaluate the effect of shrinkage and creep on the mechanical behavior of steel-concrete composite segment.The results show that the stress of the steel structure doubles and the stress of the concrete is reduced by 1/2,considering the shrinkage of the concrete.Considering 3 years of creep,the stress of the steel shell is 1.9~2.47 times the instantaneous stress,while the concrete stress is 0.13 times the instantaneous stress.The shrinkage and creep have also changed the force transmission mode of the steel-concrete composite segment.Considering shrinkage and creep,the increase of the nonuniformity of the force transmission is 0.13 and 0.44 respectively,and the maximum increase of shear force at the end of steel-concrete composite segment is 75%and 150%respectively.