预应力可回收钢绞线混凝土桩抗弯及抗剪特性研究

Research on flexural and shear properties of prestressed recycled steel strand concrete piles

针对现有混凝土桩水平承载力低和变形能力差的问题,提出了新型采用可回收预应力锚索技术的不均匀配筋预应力混凝土实心圆桩。通过4根全比尺模型试验桩的抗弯及抗剪试验、塑性损伤有限元分析,对比分析了预应力可回收钢绞线混凝土桩与普通混凝土桩的抗弯及抗剪承载力、变形特征及塑性破坏规律等方面的差异。结果表明:以可回收钢绞线替代部分钢筋作为主筋可以有效提高混凝土桩受弯、受剪状态下的承载力和变形特性;预应力可回收钢绞线混凝土桩在受弯、受剪工况下的裂缝明显小于普通混凝土实心桩,且充分发挥了混凝土的抗压性能;建立的塑性损伤有限元模型可以合理预测该新型桩的受弯、受剪性能,有限元分析得到的桩身裂缝分布与试验结果拟合较好。

Aiming at the problems of low horizontal bearing capacity and poor deformation capacity of the existing concrete piles,a prestressed concrete solid circular pile with uneven reinforcement is proposed using the recoverable prestressed anchor cable technology.Through the flexural and shear tests of four full-scale model test piles,and the finite element analysis of plastic damage,the flexural and shear bearing capacities and deformation characteristics of prestressed recoverable steel strand concrete piles and ordinary concrete piles were compared and analyzed.and plastic failure laws.The results show that the use of recycled steel strands to replace part of the steel bars as the main reinforcement can effectively improve the bearing capacity and deformation characteristics of concrete piles under bending and shearing conditions;The cracks are obviously smaller than ordinary concrete solid piles,and the compressive performance of concrete is fully exerted;the established plastic damage finite element model can reasonably predict the bending and shearing performance of the new type of piles.The test results fit well.