摘要
为研究耐火钢方钢管混凝土轴心受压柱的承载性能,设计并制作了6根耐火钢方钢管混凝土长柱并进行了轴压试验,研究了焊接残余应力、长细比、宽厚比、钢材强度等级对试件承载力及关键截面应变发展的影响规律;建立了考虑耐火钢焊接残余应力影响的有限元模型,基于验证后的模型开展了焊接残余应力、长细比及宽厚比对轴压承载性能的参数分析.研究结果表明:由于耐火钢方钢管焊接残余应力较普通钢小,耐火钢方钢管混凝土柱的稳定系数较普通钢方钢管混凝土柱高,且随着长细比增加,其差值呈先增大后减小的趋势.短柱趋于强度破坏,其极限承载力与钢管对混凝土的约束作用有关,宽厚比越小,约束效应带来的混凝土抗压强度提高幅度越大,稳定系数越大;而中长柱则因受二阶效应影响,约束效应不明显,稳定系数主要受焊接残余压应力影响,因此,宽厚比越大稳定系数越大.将试验与参数分析结果与国内外现行规范进行对比,我国规范及美国规范预测值分别低于参数分析结果32%和9%,欧洲规范预测值平均低于参数分析结果7%,预测结果精度最高.
To study the overall bearing capacity of concrete-filled fire-resistant square steel tubular(CFFRSST)columns under axial compression,six CFFRSST columns were designed and tested.The study examined the ultimate bearing capacity and strain development at key locations of the specimens with different welded residual stresses,slenderness ratios,with-to-thickness ratios,and steel strength grades.Besides,the finite element models(FEM)of CFFRSST columns were established,considering the welded residual stress.Based on the validated FEM,further analyses were conducted to evaluate the influence of the welded residual stress,slenderness ratio and width-to-thickness ratio on the axial compression behavior.The results show that the overall stability coefficients of CFFRSST are higher than that of conventional-strength steel concrete-filled square steel tubular(CSSCFSST)columns due to the lower welded residual stress of fire-resistant steel than conventional-strength steel.Furthermore,the differences in overall stability coefficients between the CFFRSST column and the CSSCFSST column increases initially and then decreases with the increase of slenderness ratios.Short columns are more prone to strength failure,and their ultimate bearing capacity are significantly influenced by the interaction between the steel tube and the concrete.As the width-to-thickness ratio decreases,the concrete compressive strength improves due to the constraint effect,leading to a higher stability coefficient.In contrast,the failure of medium and long columns is primarily governed by second-order effects,where the constraint effect is less pronounced.The stability coefficient of columns is primarily affected by welded residual compressive stress,which increases as the width-tothickness ratio increases.The ultimate bearing capacity obtained from the parametric analysis were compared with predictions from current design codes.The results show that the predictions from Chinese and American codes are lower than the parametric analysis by about 32%and 9%,respectively,while the European code underestimates it by about 7%,providing the most accurate predictions among the three.
作者
王彦博
陈美玲
叶泽华
李国强
WANG Yanbo;CHEN Meiling;YE Zehua;LI Guoqiang(College of Civil Engineering,Tongji University,Shanghai 200092,China;State Key Laboratory for Disaster Reduction in Civil Engineering,Tongji University,Shanghai 200092,China)
出处
《湖南大学学报(自然科学版)》
北大核心
2025年第11期1-14,共14页
Journal of Hunan University:Natural Sciences
基金
上海市科技计划项目(23DZ1202303)。
关键词
方钢管混凝土柱
耐火钢
抗火性能
焊接残余应力
承载力
concrete-filled square steel tubular column
fire-resistant steel
fire resistance
welded residual stress
bearing capacity
