配置CRB600H高强箍筋混凝土柱抗震抗剪性能试验研究

Experimental Research on Seismic Shear Behavior of CRB600H High-strength Stirrups Concrete Columns

通过8根配置CRB600H高强箍筋混凝土柱和1根配置HRB400普通箍筋混凝土柱的低周反复加载试验,对比分析了高强箍筋混凝土柱的抗震抗剪性能,探讨了配箍率、箍筋间距、箍筋形式、轴压比和混凝土强度对其抗震抗剪性能的影响,并对高强箍筋的应力发挥水平进行了研究。此外,通过将国内外发生剪切破坏的400MPa级普通箍筋柱试验数据,与高强箍筋柱试验结果进行对比分析,进一步研究CRB600H箍筋柱与普通箍筋柱的性能差异。结果表明:CRB600H高强箍筋柱与400MPa级普通箍筋柱相比,抗剪承载力差异不大,但具有更好的延性和极限变形能力;现行混凝土规范高估了高强箍筋柱的抗震抗剪承载力,偏于不安全;增加配箍率可提高柱的极限变形能力;在相同配箍率下,密配小直径箍筋和采用复合箍筋形式可改善柱的的抗震性能;限制轴压比和在一定范围内采用强度较高的混凝土对提高柱的抗震性能有利;在给出配箍率替代本文配箍率下,达到峰值承载力时,柱端CRB600H箍筋屈服,箍筋强度能够充分发挥。

Research was conducted on eight CRB600H high-strength stirrups concrete columns and a HRB400 normal-strength stirrups concrete column bylow-cyclic reversed loading experiment.The seismic shear behavior of high-strength stirrups concrete columns were compared and analyzed.The influences of stirrup ratio,stirrup spacing,stirrup configuration,axial compression ratio and concrete compression strength on the seismic shear behavior of high-strength stirrups columns were studied.The stress level of the transverse reinforcements were also evaluated.Then comparison analysis was carried out on the experimental data between normal-strength stirrups columns and CRB600H stirrups columns to thoroughly evaluate seismic shear behavior of the CRB600H stirrups columns.Research results indicate that compared with 400 MPa grade stirrups columns,CRB600H stirrups columns have little difference in shear capacity,while have better ductility and ultimate deformation capacity.The current concrete code would overestimate the seismic shear strength of high strength stirrups columns.Increasing stirrup ratio can improve the ultimate deformation capacity.At a given stirrup ratio,seismic behavior of columns with small stirrup spacing and composite stirrups is better.The seismic performance of columns can be improved by limiting the axial compression ratio and using the higher strength concrete.At the peak bearing capacity,high-strength stirrups reach the yield,and strength of CRB600H stirrups are developed fully.