摘要
由热平衡理论建立室内平均温度-时间关系计算模型;以传热学理论建立混凝土梁、柱截面温度场计算模型;以混凝土结构耐火理论建立框架中柱的高温承载力计算模型;以弹性理论建立柱子的温度轴力计算模型;以四面受火中柱(轴心受压)达到承载能力极限状态的时间作为底框架商住楼在火灾中的倒塌时间。结果表明,我国仅有的2个倒塌案例和4次火灾试验结果与数值计算平均误差为5%;数值计算中采用实际温度-时间关系作为火作用,混凝土强度采用在温度和初应力作用下的抗压强度并考虑柱子的温度轴力更为合理。
The average indoor temperature-time model is established based on thermal equilibrium theory;the cross-section temperature field calculation model of concrete beams and columns is established by heat transfer theory;the bearing capacity calculation model of frame middle columns in fire is established based on fire resistance theory of concrete structure;the thermal axial force calculation model of columns is established based on elasticity theory;the time when middle columns（all sides are exposed to fire and forced by axial compression） reach bearing capacity limit state is taken as collapse time of bottom RC frame business-living building in fire.The results show that the average error is 5% between the result of calculation in this method and that of the only 2 bottom RC frame business-living building collapse cases in China and 4 fire tests;using temperature-time relationship as fire condition in numerical calculation,using compressive strength effected by heat and initial stress as the concrete strength,and considering thermal axial force are more reasonable.
出处
《消防科学与技术》
CAS
北大核心
2011年第7期557-562,共6页
Fire Science and Technology
基金
国家"十一五"科技支撑计划项目(2006BAK06B05-1)
关键词
钢筋混凝土
底框架结构
火灾
耐火极限
数值计算
reinforced concrete
bottom frame
fire
fire resistance
numerical analysis
