火灾下双钢管混凝土复合短柱的性能与承载力计算方法
Performance and bearing capacity calculation method of concrete-filled double steel tubular composite stub columns under fire
杨青天 1多飞 1张晋川 1侯立群 2陈适才1
作者信息
- 1. 北京工业大学 土木工程系,北京 100124
- 2. 中铁建设集团有限公司,北京 100040
- 折叠
摘要
为研究双钢管混凝土复合短柱的耐火性能,建立了双钢管混凝土复合短柱精细化数值模型,在类似构件试验成果验证的基础上,开展其高温反应规律和耐火性能影响因素研究;全面分析了内管径厚比、外管径厚比、内外管直径比等参数的影响,以及不同截面组合形式(内圆外圆、内方外圆和内圆外方)双钢管混凝土短柱的耐火极限.基于热传导分析理论推导双钢管混凝土短柱截面的温度场分布公式,并根据有限元模拟结果对公式进行修正;最后基于温度等效原理进一步提出了火灾条件下双钢管混凝土短柱截面温度场的简化计算公式和承载力计算方法.结果表明:双钢管混凝土复合短柱具有较好的耐火性能,在直径不变时增大内钢管的厚度以及在厚度不变时增加内钢管的直径都有利于耐火极限的提高;在荷载作用和含钢率相同的条件下,不同截面组合形式的双钢管混凝土短柱耐火极限相差不大,但总体上双圆钢管混凝土短柱的耐火性能偏优;提出的温度场简化计算公式和基于等效温度的承载力计算方法与有限元结果相对误差都在15％以内.
Abstract
In order to study the fire resistance of concrete-filled double steel tubular composite stub columns(CFDST),a refined numerical model of CFDST was established.Based on the verification of test results of similar components,the high-temperature response law and fire resistance influence factor of CFDST were analyzed.The effects of internal pipe diameter thickness ratio,external pipe diameter thickness ratio,internal and external pipe diameter ratio were comprehensively analyzed.The fire resistance limits of CFDST with different section combinations(inner circle and outer circle,inner square and outer circle,inner circle and outer square)were compared and analyzed.Based on the theory of heat conduction analysis,the temperature field distribution formula of CFDST section was deduced,and the formula was modified according to the results of finite element simulation.Finally,based on the principle of temperature equivalence,the simplified calculation formula and bearing capacity calculation method of section temperature field of CFDST under fire were further proposed.The results show that CFDST has good fire resistance.Increasing the thickness of the inner steel tube when the diameter is unchanged and increasing the diameter of the inner steel tube when the thickness is unchanged are conducive to the improvement of the fire resistance limit.Under the condition of the same load and steel content,the fire resistance limit of CFDST with different section combinations is almost the same,but on the whole,the fire resistance of double circular steel tube concrete stub column is better.The difference between the simplified calculation formula of temperature field,the bearing capacity calculation method and the finite element results is less than 15％.
关键词
双钢管混凝土复合短柱/温度场/耐火极限/简化计算公式/承载力Key words
concrete-filled double steel tubular composite stub column/temperature field/fire re-sistance limit/simplified calculation formula/bearing capacity引用本文复制引用
基金项目
国家自然科学基金项目(51678016)
国家自然科学基金项目(52278471)
出版年
2024
NETL
NSTL
维普
万方数据