横向弯曲效应对大跨度人行悬索桥短吊索影响的分析

Analysis on the Effects of Short Suspender on Large-span Pedestrian Suspension Bridges Considering Transverse Bending

以某新建大跨度人行悬索桥为工程背景,通过理论分析和有限元仿真,探讨了横向弯曲效应对吊索应力的影响。研究结果表明:抗风缆可有效减小横向变位,但其张力对横向变位影响程度较小;跨中短吊索横向弯曲效应明显,在无抗风缆结构中最大弯曲附加应力约恒载应力的1.85倍,有抗风缆结构中附加应力仍达恒载的1.14倍;考虑弯曲效应下,跨中部分吊索组合应力超出规范限值,无抗风缆结构中最大超出幅度约95%,有抗风缆结构中最大超出幅度约40%;分析建议当吊索上下端横向位移差大于吊索长度的0.01倍时,吊索设计需关注弯曲附加应力,可采用设纵横双向转动销铰的钢拉杆替代钢丝吊索,以减小弯曲效应的影响。

Takeing a newly-built large-span pedestrian suspension bridge as engineering background,the influence of transverse bending effect to suspender stress was analyzed by theoretical analysis and finite element simulation.Research results show that the transverse displacement is reduced by wind cables on the structures,but the tension of the wind cables has little influence to transverse displacement.The bending effect of suspender at mid-span is extremely significant.Concretely,the maxmum bending stress can be 1.85 times that of dead loads’without wind cables and 1.14 times that of dead loads’with wind cables.Considering the bending effect,partial suspender combination stress exceed the limit value of the specification,meanwhile the excess rang is 95%without wind-cables and 40%with wind-cables.When the displacement diffence on suspender two ends is larger than 0.01 times of suspender length,bending stress need be especially focused.Necessary,the steel wire suspenders can be replaced by rigid suspenders with turn hinges in two sides to avoid the obvious bending effect.