改进型PHC管桩抗震性能试验研究

发布时间：2018-05-07 20:24

本文选题：PHC管桩 + 钢纤维　；参考：《天津大学》2014年博士论文

【摘要】：PHC管桩由于单桩承载力高和施工速度快等诸多优点在工程中得到了广泛的应用。但国外的一些实际震害调查表明,在地震荷载作用下,管桩会由于抗弯承载力不足而发生破坏。本文通过低周往复加载试验研究了PHC管桩在往复荷载作用下的破坏模式和受力性能。在此基础上采取一系列措施对PHC管桩进行改进并进行了往复加载试验,研究PHC管桩受力性能的改进效果。通过低周往复加载试验分析PHC管桩在地震荷载作用下的破坏特征,滞回耗能,累积损伤以及延性性能等,结果表明,PHC管桩在往复荷载作用下发生脆性破坏。其滞回曲线捏缩严重,耗能性能差。体积配箍率增加0.08%,PHC管桩的位移延性提高了29%。增大体积配箍率可以提高PHC管桩在往复荷载作用下的延性。桩身混凝土中掺入钢纤维的SFPHC管桩,混合配筋的PRC管桩和填芯管桩的抗震性能试验分析表明,在桩身混凝土中掺入1.5%的剪切端钩型钢纤维可以使管桩的位移延性提高38%。PRC管桩在往复荷载作用下发生延性破坏,其极限承载力相比于PHC管桩提高了30%~60%。随着非预应力筋与预应力筋配筋强度比的增大,PRC管桩的极限承载力呈增大的趋势。当配筋强度比在0.9~1.2之间时,PRC管桩的位移延性相比于PHC管桩提高了60%以上,表现出很好的延性性能。填芯后,PHC管桩、SFPHC管桩和PRC管桩的位移延性分别提高了23%、12%和13%。填芯可以提高管桩在往复荷载作用下的延性。对管桩在往复荷载作用下的受力性能进行有限元分析并与试验结果对比,在验证模型可行性的基础上,深入分析了多项因素对PRC管桩抗震性能的影响。结果表明,增大预应力筋配筋率和非预应力筋配筋率可以提高PRC管桩在往复荷载作用下的极限承载力。随着预压应力的增大,PRC管桩的位移延性系数呈明显下降的趋势。
[Abstract]:PHC pipe pile has been widely used in engineering because of its high bearing capacity and fast construction speed. However, some actual earthquake damage investigations abroad show that pipe piles will be destroyed due to insufficient flexural bearing capacity under earthquake load. In this paper, the failure mode and mechanical behavior of PHC pipe pile under reciprocating load are studied by low cycle reciprocating loading test. On the basis of this, a series of measures were taken to improve the PHC pipe pile and the reciprocating loading test was carried out to study the effect of improving the mechanical performance of the PHC pipe pile. The failure characteristics, hysteretic energy dissipation, cumulative damage and ductility of PHC pipe pile under seismic loading are analyzed by low-cycle reciprocating loading test. The results show that brittle failure of PHC pipe pile occurs under reciprocating load. Its hysteretic curve pinch is serious, the energy dissipation performance is poor. The displacement ductility of PHC pipe pile is improved by 29%. The ductility of PHC pipe pile under reciprocating load can be improved by increasing the volume hoop ratio. The seismic behavior of SFPHC pipe pile with steel fiber in pile body concrete, PRC pipe pile with mixed reinforcement and core filled pipe pile are analyzed. The displacement ductility of 38%.PRC pipe pile can be improved by adding 1.5% shear end hook steel fiber into the concrete of pile body, and the ultimate bearing capacity of 38%.PRC pipe pile under reciprocating load can be increased by 3060% than that of PHC pipe pile. The ultimate bearing capacity of PRC pipe pile increases with the increase of the strength ratio of non-prestressed and prestressed reinforcement. The displacement ductility of the pile is more than 60% higher than that of the PHC pile when the strength ratio of reinforcement is 0.90.2.It shows good ductility. The displacement ductility of PRC pipe pile and SFPHC pipe pile are increased by 23% and 13% respectively. Core filling can improve ductility of pipe pile under reciprocating load. The finite element analysis of the behavior of pipe pile under reciprocating load is carried out and compared with the experimental results. On the basis of verifying the feasibility of the model, the influence of many factors on the seismic behavior of PRC pipe pile is deeply analyzed. The results show that the ultimate bearing capacity of PRC pipe piles under reciprocating load can be improved by increasing the reinforcement ratio of prestressed tendons and the reinforcement ratio of non-prestressed tendons. With the increase of preloading stress, the displacement ductility coefficient of PRC pipe pile decreases obviously.
【学位授予单位】：天津大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TU473.1;TU435

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