钢管含粗骨料超高性能混凝土短柱轴压性能研究

考虑钢纤维掺量、粗骨料替代率和钢管厚度三个参数，设计制作了14根短柱试件。通过全截面轴心受压试验，考察了试件的破坏形态、荷载-变形曲线、荷载-应变曲线和极限承载力，分析了各参数对短柱轴心受压性能的影响规律。试验结果表明:当套箍系数0.217≤ ξ < 0.883时试件主要呈现剪切破坏形态；套箍系数0.883 ≤ ξ ≤1.431时试件主要呈现腰鼓破坏形态。在相同钢管厚度下，粗骨料的掺入能有效提高试件承载力。参考已有钢管混凝土规程，提出了CA-UHPCFST短柱轴心受压承载力计算公式，可供工程设计参考。

STUDY ON AXIAL COMPRESSION BEHAVIOR OF CA-UHPC FILLED STEEL TUBE STUB COLUMNS

In this study, 14 stub columns filled with ultra-high-performance concrete containing coarse aggregate (CA-UHPC) were prepared to study the axial compressive behaviors, in which the effects of steel fiber content, coarse aggregate substitution rate, and steel tube thickness were considered. The failure pattern, load-deformation curve, load-strain curve and bearing capacity of the specimens were investigated. The results show that: when the hoop coefficient falls within the range from 0.217 to 0.833, the specimens fail in a shear failure mode; while the coefficient range is from 0.883 to 1.43, the failure of specimens is mainly dominated by the drum damage. Moreover, in the case of the same steel pipe thickness, the incorporation of coarse aggregate can effectively improve the bearing capacity of the specimens. Based on the current concrete-filled steel tube specifications, a modified formula suitable for calculating the axial compression bearing capacity of CA-UHPCFST stub columns is put forward, which can be used as a reference for pertinent engineering design.