摘要
为系统研究非均匀受火时钢管混凝土结构的抗火性能,在合理选取不同阶段钢材和混凝土的热力本构模型的前提下,基于ABAQUS有限元平台,建立方形截面钢管混凝土柱三面受火数值模型。对经历常温加载、升温、降温以及火灾后等不同阶段的钢管混凝土柱力学性能进行初步分析,并与已有的试验进行对比验证;同时,分析了升温时间比t0、保护层厚度a、火灾荷载比n及长细比λ等参数对构件受火性能的影响。结果表明,三面受火时,钢管混凝土柱的破坏形式与均匀受火时有明显差异,因为柱截面温度的不均匀分布会使其产生附加偏心距,发生失稳破坏;三面受火后,钢管混凝土柱的极限承载力和延性均有不同程度的降低;长细比及升温时间比对三面受火时的方钢管混凝土柱力学性能影响较为明显,承载力和延性有明显的下降。
In order to study systematically the fire resistance of concrete-filled steel tubular （CFST） structure, this paper presents a finite element model of concrete-filled square hollow sec- tion columns exposed to three-surface fire based on ABAQUS. The reasonable thermal and mate- rial models of steel and core concrete are used in the FE model. The FE model is developed to study the mechanical performance of CFST columns exposed to overall stage fire, including load- ing at ambient, heating, cooling and post-fire. The FE model is verified by the others＇ experi- mental results. The parametric analysis of FE model is performed, such as fire load ratio of col- umn, depth of fire protection, slenderness ratio of column and fire time ratio of column. The re- sults show that the failure modes in non-uniform fire conditions are different from the uniform fire conditions due to the additional eccentricity. The ultimate bearing capacity and initial stiff- ness of the CFST columns are reduced due to the high temperature. The fire time ratio of column and slenderness ratio of column have significant effects on the mechanical performance of CFST columns exposed to three surface fire.
出处
《防灾减灾工程学报》
CSCD
北大核心
2015年第1期100-105,共6页
Journal of Disaster Prevention and Mitigation Engineering
基金
国家自然科学基金项目(51268038
51468037)
甘肃省高等学校科研项目(2013A-032)资助
关键词
钢管混凝土(CFST)柱
火灾全过程
非均匀受火
力学性能
数值模拟
concrete-filled steel tubular（CFST） column
overall stage fire
non-uniform exposure to fire
mechanical performance
numerical simulation
