几何缺陷对张弦梁预应力张拉影响的力学分析

用有限元方法分析了张弦梁结构上弦平面外几何缺陷在预应力张拉过程中可能造成的力学影响,比较了张弦梁结构不同的上弦截面形式对平面外几何缺陷的敏感性,指出张弦梁上弦采用H形截面时,张弦梁结构可能具有对上弦平面外几何缺陷的敏感性,施工过程应考虑这一因素;张弦梁上弦采用平面外刚度较大的箱形截面时,可避免结构对上弦平面外几何缺陷的敏感性,施工时可在地面将张弦梁一次张拉到位,避免高空预应力张拉的不便,减小施工难度.

BSS mechanical analysis of influence from geometric imperfection in prestress-tension stage

The paper analyzes the mechanical influences from BSS(beam string structure) geometric imperfection out of plane of top chord in stage of prestress-tension by FEA,researches the sensibility to geometric imperfection out of plane of top chord derived from different section types of top chord of BSS and points out that the BSS with H-section top chord,which,in possession of less rigidity out of plane,will be sensitive to geometric imperfection out of plane of top chord.The factor should be considered in construction and the BBS with box-section top chord,which,in possession of more rigidity out of plane,can avoid the sensibility,therefore can be tensioned to design value of prestress-tension on ground,decrease difficulty of construction.