摘要
由于结构的连续性,使得局部火灾下的网架结构中圆钢管杆件表现出典型的轴向约束杆件力学特征,这种轴向约束的存在使杆件高温屈曲后仍具有一定的承载力。基于轴向约束杆件高温屈曲后力学特征量相关方程,采用MATLAB数学求解器,开展大规模参数分析,得出关键参数影响下,轴向约束圆钢管高温屈曲后极限承载力随着长细比的增加而先降低后趋于不变,随着荷载比的增加而先略有增加后增幅趋缓,随着约束刚度比的增加而先增加后不变。基于2 300个算例结果,拟合得到约束圆钢管高温极限承载力计算公式。拟合计算公式与相关方程得到的解析解吻合较好,可作为网架结构圆钢管杆件抗火承载力验算依据,也为进一步研究网架结构受火失效机理奠定了基础。
The continuity of structure can cause confinement effect in the steel circle pipes of grid structure subjected to localized fire. The restrained members in grid structure under fire condition have certain post buckling loading bearing capacity. A correlation equation for calculating the post-buckling load capacity is proved. A comprehensive parametric analysis based on the correlation equation is conducted using the MATLAB software. Three important conclusions are obtained. Increasing slenderness ratio can make post-buckling load-bearing capacity increase and then tends to be the same. The post buckling load-bearing capacity increases slightly and then almost keeps unchanged with the increase of load ratio,and the post-buckling load-bearing capacity increases first and then remains at a certain level with the increasing confinement stiffness ratio. The formula for calculating the post-buckling load-bearing capacity of the restrained circular tube is obtained based on 2 300 numerical examples. The results of the fitting formula agree well with the correlation equation, which can be used to cheek the ultimate fire resistance of restrained members in grid structure. This study can provide a reference for the study of failure mechanism subjected to fire.
作者
张浩
杜咏
王慧蕾
ZHANG Hao;DU Yong;WANG Huilei(College of Civil Engineering, Nanjing Tech University, Nanjing 211816, China)
出处
《建筑钢结构进展》
CSCD
北大核心
2018年第3期72-77,共6页
Progress in Steel Building Structures
基金
国家自然科学基金(51378259)
江苏省住房和城乡建设厅科技项目(2014JH13)
关键词
局部火灾
网架结构
轴向约束杆件
屈曲后承载力
localized fire
grid structure
axially restrained member
post-buckling load bearing capacity
