钢管砂轻混凝土轴压短柱力学性能研究

Study on mechanical performance of sand-lightweight concrete filled steel tube stub column under axial compression

为了研究钢管砂轻混凝土短柱的轴压性能,以砂轻混凝土中河砂与陶砂的体积比例为变化参数,制作了3个圆钢管砂轻混凝土短柱试件和3个方钢管砂轻混凝土短柱试件,进行了静力单调轴压性能试验。观察了试件的受力过程和破坏形态,获取并分析了试件的应力-应变全过程曲线,基于统一强度理论、极限平衡理论和叠加理论分别计算了钢管砂轻混凝土短柱试件的轴压极限承载力。结果表明:钢管砂轻混凝土轴压短柱的外部钢管均向外屈曲,核心砂轻混凝土被压碎,方钢管砂轻混凝土短柱上部破坏程度较圆钢管砂轻混凝土短柱严重;钢管砂轻混凝土短柱的应力-应变曲线存在弹性、弹塑性和塑性三个受力阶段;建议采用基于叠加理论的AIJ-1997(CECS 159:2004或AIJ-1997)进行圆(方)钢管砂轻混凝土短柱轴压极限承载力的设计计算。

To study the axial compression performance of sand-lightweight concrete filled steel tube(SLCFST)stub column,three sand-lightweight concrete filled circular steel tube(C-SLCFST)stub column specimens and three sand-lightweight concrete filled square steel tube(S-SLCFST)stub column specimens are made to carry out the static monotonic axial compression performance test,by taking volume ratio of river sand and ceramic sand in sand-lightweight concrete into account.The stress process and failure mode of the specimens are observed,stress-strain curves of specimens are obtained and analyzed,the ultimate bearing capacity of SLCFST stub column specimens is calculated,respectively,based on unified strength theory,limit equilibrium theory and superposition theory.Results show that the outer steel tubes of SLCFST stub columns are buckled outward,core sand-lightweight concrete are crushed,and the damage of upper part in S-SLCFST stub columns is more serious than that in C-SLCFST stub columns.There are three stages as elastic stage,elastic-plastic stage and plastic stage in the stress-strain curves of SLCFST stub columns.It is suggested that AIJ-1997(CECS 159:2004 or AIJ-1997)based on superposition theory can be adopted to design the ultimate bearing capacity under axial compression for C-SLCFST(S-SLCFST)stub columns.