大尺寸RPC管-HSC组合柱轴压性能试验研究

Experimental Research on Axial Compression Performance of Large-scale HSC-filled RPC Tube

在活性粉末混凝土(RPC)预制管内部浇筑高强混凝土,形成RPC管-高强混凝土(HSC)组合柱,扩展了RPC管-混凝土组合柱(CFRT)这一新型组合结构的范围。开展了RPC管离心法成型的配合比与工艺研究,成功试制了RPC管。对4组大尺寸CFRT和1组箍筋约束高强混凝土柱试件进行轴压试验,试验参数为内部混凝土和纵筋配置率。结果表明:内部填充HSC的CFRT柱在整个受力过程中,预制管身基本完整,抗压性能显著优于用于对比的箍筋约束高强混凝土柱;CFRT柱的抗压强度随内部混凝土强度的提高而提高,但约束效应逐步降低,对CFRT柱的内部混凝土的强度应该有所限制;在内部混凝土中配置纵向钢筋,对CFRT的延性影响不大;基于Mander(1988)约束模型,提出了内部填充高强混凝土的CFRT柱轴向承载力计算方法,模型的预测结果与试验结果吻合较好。

Concrete-filled reactive powder concrete tube(CFRT)is an innovative composite structure based on confinement effect.Reactive powder concrete(RPC)tube filled with high-strength concrete(HSC)core,named RPC-HSC composite column,was investigated in this work.The mixture ratio of RPC for precast spun tube were investigated and all RPC tubes in the test were manufactured by spinning process in factory.Axial compression tests were carried out on 4 groups of large-scale CFRT columns and one group of steel-confined HSC columns.The results showed that in the whole compression process,the RPC tube of CFRT column with inner HSC was in good condition,and displayed better compression performance than the control columns.The increment of inner concrete’s strength led to increasing compressive strength of the CFRT column,but a gradually decline of the confinement effect,which suggested the necessity of strength limitation on the internal concrete for CFRT column.The longitudinal reinforcement in the inner concrete has little effect on the ductility of the CFRT columns.Based on the Mander(1988)model,we proposed a calculation method for the carrying capacity of CFRT column filled with HSC,and the predictions by this method coincided well with the experimental results.