柱中拼装RC柱施工阶段轴压性能试验研究

EXPERIMENTAL STUDY ON THE AXIAL COMPRESSION BEHAVIOR OF PREFABRICATED RC COLUMNS LINKED AT MIDDLE REGION AT DIFFERENT STAGES OF CONSTRUCTION

  • 摘要: 完成了5个柱中拼装RC柱和2个整浇RC柱的轴压性能试验,研究拼装后浇段养护时间对试件施工阶段轴压性能的影响。试验研究表明,不同施工阶段拼装RC柱轴压性能有较大差别。后浇前,拼装RC柱轴压承载力为整浇RC柱的46.2%。后浇后,拼装RC柱轴压承载力随后浇段养护时间的增加而增加,养护28 d的试件承载力为整浇RC柱的87.9%。由于上柱段锥形界面处对后浇段的楔入挤压作用,拼装RC柱后浇段发生明显的侧向膨胀,后浇段箍筋约束作用明显,试件破坏形态有明显的塑性发展过程。对拼装RC柱轴压受力机理进行了分析,提出了拼装RC柱轴压承载力计算公式,计算结果与试验吻合良好。该文成果可为装配式RC结构的工程实践提供参考。

     

    Abstract: Five prefabricated RC columns linked at the middle region and two monolithically casted RC columns were tested under axial compression loads to investigate the influence of linkage site curing time on the axial compression performance of specimens at different stages of construction. The results indicate that obvious differences in axial compression performance for prefabricated RC columns exist at different construction stages. The axial strength of the prefabricated RC column without casting concrete at the linkage site is 46.2% that of the monolithically casted RC columns. After concrete is cast, the axial strength of prefabricated RC columns increases with the increase of curing time for the linkage site. When the curing time for the linkage site is 28 days, the axial strength of the specimen is 87.9% that of the monolithically casted RC columns. Due to the pressure exerted at the cone-shaped cross section of the upper columns, the linkage site of the prefabricated RC columns expanded laterally, which gave rise to the confinement of the concrete by the stirrups. The failure modes of the specimens show distinct plastic characteristics compared with those of the monolithically casted RC columns. The mechanical analysis of axial compression for prefabricated RC columns was carried out and a calculation method for axial strength is proposed. Calculated results show good agreement with test results. This paper can be referenced for the engineering practice of prefabricated RC structures.

     

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