圆钢管超高性能混凝土短柱偏压力学性能研究

o study the eccentric compression performance of ultra-high performance concrete filled with steel tubular short columns,12 circular specimens were designed and tested under eccentric compression by taking the load eccentricity and diameter-thickness ratio as variation parameters.The failure mode,load-deflection curves,strain of steel tubes,and deformation coefficient of these members were analyzed.The effects of main factors on the eccentric compression performance of short columns were explored.The results show that the failure of specimens is characterized by the yielding of the steel tube,followed by the crushing of the core concrete.The load-deflection curves have clear peak points,and the greater the eccentricity and the smaller the diameter-to-thickness ratio,the smoother the drop section of the load-deflection curves.At 60% of the peak load,the steel tube begins to produce obvious confinement; at 90% of the peak load,the section deformation no longer meets the plane section assumption.As the eccentricity increases,the load-bearing capacity and stiffness of the specimens decrease,and the decrease in the diameter-to-thickness ratio can reduce this adverse effect.Based on the experiment,the N-M curve of the short column is analyzed by numerical simulation and an expression for the relationship between the critical eccentricity and the confining coefficient is established.The practical calculation method of short column bearing capacity is proposed,and the theoretical and experimental results are in good agreement.