预应力钢绞线超高强混凝土管桩受弯性能研究

为解决普通预应力超高强混凝土管桩水平承载力低和变形能力差的问题，提出了预应力钢绞线超高强混凝土管桩。通过3种常用桩型6根试件的足尺受弯性能试验、有限元分析，对比了预应力钢绞线超高强混凝土管桩与普通预应力超高强混凝土管桩在抗裂性能、受弯承载力、变形能力及破坏特征等方面的差异。研究结果表明：以钢绞线替代钢棒作为主筋可以有效提高管桩受弯状态下的变形能力和承载力；预应力钢绞线超高强混凝土管桩均以受压区混凝土压碎破坏，而普通预应力超高强混凝土管桩均以预应力钢棒拉断破坏；所建立的数值模型可以合理预测管桩的受弯性能，模拟得到的桩身裂缝分布与试验结果吻合较好。

Study on flexural performance of prestressed steel strand reinforced ultra-high strength concrete pipe piles

Prestressed steel strand reinforced ultra-high strength concrete pipe piles were proposed to solve the problems of low horizontal load-carrying capacity and poor deformation capacity of ordinary prestressed ultra-high strength concrete pipe piles. In the present study, the differences between prestressed steel strand reinforced ultra-high strength concrete pipe piles and ordinary prestressed ultra-high strength concrete pipe piles in anti-cracking performance, flexural capacity, deformation capacity and damage characteristics were comparatively investigated through full-scale flexural performance experiments of six specimens of three kinds of commonly-used pile types as well as corresponding finite element analysis and theoretical calculation using design formulas of the code. The results show that replacing steel bars with steel strands as the main reinforcement can effectively improve the deformation capacity and the load-carrying capacity of the pipe piles under bending conditions. The failure mode of prestressed steel strand reinforced ultra-high strength concrete pipe piles is concrete crushing in the compression zone, while for ordinary prestressed ultra-high strength concrete pipe piles, the prestressed steel bar is broken. The established numerical model can reasonably predict the flexural performance of pipe piles, and the simulated crack distribution of the pile body is in good agreement with the experimental results.