拉索预应力折线型立体桁架拱布索方案研究

针对折线型立体桁架拱结构,提出了4种拱平面内的布索方案,研究了4种方案下预应力拱结构的静力及稳定性能,分别从结构位移的减小、索初始预拉力值的高低、水平支反力的降幅、杆件内力分布的均匀性及结构稳定性的提高5个方面与未布索立体桁架拱作了综合对比.结果表明,按照桁架拱在极限荷载作用下的屈曲形态布置撑杆拉索能够最有效地改善拱的静力性能,提高其稳定极限承载力.另外,由对预应力桁架拱的失稳模态分析发现,拉索通过撑杆对结构施加预应力能更有效地约束结构的整体变形.

Research on the Arrangement Styles of Cables for Pretensioned Folded Line Type 3D-trussed Arch

For the folded line type three-dimensional (3D) trussed arches, four arrangement styles of cables in the arch plane were presented. The static and stability property of the pretensioned 3D trussed arch in those four arrangement styles was studied. The numerical results including the decrease in structural displacement, the initial tensile force of cables, the reduction in horizontal reaction force, the uniformity of distribution of member forces and the improvement of structural stability were compared with those of the corresponding 3D-trussed arch, and it has been shown that the mechanical properties of the arch can be greatly improved with the arrangement style where the struts and cables were arranged according to the buckling shape of the arch subjected to the ultimate load. In addition, the analysis results of the instability modes of the pretensioned 3D-trussed arch indicate that the global deformation of the arch can be controlled effectively by introducing struts to the prestressing system.