超高强混凝土型钢组合长柱静力性能试验研究  

Experimental study on behaviours of ultra-high strength concrete encased steel columns under static load

作　　者：杜咏[1] 周汇凯 LIEW J Y Richard DU Yong;ZHOU Huikai;LIEW J Y Richard(College of Civil Engineering,Nanjing Tech University,Nanjing 211816,China;Department of Civil and Environmental Engineering,National University of Singapore,Singapore 117576,Singapore)

机构地区：[1]南京工业大学土木工程学院,江苏南京211816 [2]新加坡国立大学土木与环境工程学院,新加坡117576

出　　处：《建筑结构学报》2022年第2期147-156,共10页Journal of Building Structures

基　　金：国家自然科学基金面上项目(5167081607)。

摘　　要：为解决目前规范中缺乏超高强混凝土型钢组合柱设计方法和静力受压试验研究不够深入的问题,开展了5个轴心受压和4个偏心受压的立方体抗压强度为120 MPa超高强混凝土型钢长柱的静力试验,通过考察其破坏形态、轴力-挠度曲线、轴力-竖向位移曲线和轴力-应变曲线,研究了长细比、相对偏心距和箍筋间距对其静力性能的影响。试验结果表明:总体上,双肢箍筋间距减小对超高强混凝土的约束效果有一定提高,但不能有效提高试件承载力;二阶效应对试件承载力的降低随着长细比的增加而增强;应变分布满足平截面假定。随着长细比的增加,体积比0.5%的钢纤维掺量虽然不能显著提高超高强混凝土型钢长柱延性,但可延迟混凝土开裂,使型钢强度得到充分利用;超高强混凝土型钢轴心受压柱由截面强度破坏过渡为失稳破坏;偏压柱表现为失稳破坏,相对偏心距0.2的组合柱表现为小偏压破坏,而相对偏心距0.4的组合柱则表现为大偏压破坏。对比超高强混凝土型钢长柱的受压承载力试验值和现行规范建议公式计算值可得,EN1994-1-1建议公式计算值较轴心受压承载力试验值偏低,而中国JGJ138—2016中公式计算值较试验值偏高;两本规范中相关公式都低估了试件的偏心受压承载力。In order to solve the problems of insufficient design method in the current code and less research on static compression test,five ultra-high strength concrete encased steel columns under axial compression and four such columns under eccentric compression were examined.The slenderness ratio,hoop spacing and eccentricity were taken into consideration.The failure mode,load-displacement curve,load-deflection curve and load-strain curve were investigated.The decrease of the hoop spacing can enhance the constraint effect on the concrete,but could not increase the load capacity of the specimens effectively.The effect of the second order effect on the bearing capacity of the specimen increased with the increase of the slenderness ratio.The strain distribution satisfies the assumption of“plane section remains plane”.With the increase of the slenderness ratio,the use of 0.5%steel fibre by volume cannot effectively improve the ductility of the 120 MPa ultra-high strength concrete encased steel columns,but can prevent premature crack of the concrete,and the strength of core steel section were fully utilized.With the increase of slenderness ratio and the decrease of the hoop spacing,the failure mode of the specimens changes from cross section failure to buckling failure.The specimens under eccentric load show buckling failure mode.The concrete encased steel columns with 0.2 eccentricity show small eccentric compression failure mode.The concrete encased steel columns with 0.4 eccentricity show large eccentric compression failure mode.By comparing the test values of the load bearing capacity with those proposed by EN 1994-1-1 and JGJ 138—2016,the axial bearing capacity of 120 MPa ultra-high strength concrete encased steel columns is underestimated by EN 1994-1-1,while that predicted by JGJ 138—2016 is overestimated.Both codes underestimate the eccentric bearing capacity.

关 键 词：超高强混凝土型钢柱 轴心受压 偏心受压 静力试验 承载力 

分 类 号：TU398.9[建筑科学—结构工程] TU317.1