【作者】 温清清； 陈梦成； 刘超；

【Author】 WEN Qing-qing;CHEN Meng-cheng;LIU Chao;School of Civil Engineering and Architecture, East China Jiaotong University;College of Science, East China Jiaotong University;National Experimental Teaching Demonstration Center of Civil Engineering, East China Jiaotong University;Sinic Holdings (Group) Company Limited;

【机构】 华东交通大学土木建筑学院； 华东交通大学理学院； 华东交通大学土木工程国家实验教学示范中心； 新力控股(集团)有限公司；

【摘要】 以钢筋混凝土连续梁为研究对象,采用元胞自动机模拟火灾下梁截面温度扩散演化过程,考虑高温损伤对钢筋的影响,得到不同升温时间下的钢筋损伤因子。结果表明:截面各处温度随时间增长逐渐升高,且距离传热边界越近,温度越高,两面皆受火的角部位置温度最高;梁内钢筋损伤随升温时间增长而加剧,且越接近传热边界位置,钢筋的损伤速率越大。考虑非线性,基于纤维模型理论,引入钢筋损伤因子对截面刚度矩阵进行修正,对受火后的钢筋混凝土梁进行静力分析。结果表明:梁的跨中挠度随升温时间增长而增大,考虑非线性后加速了梁的变形增长;梁关键位置处的截面承载力随受拉区钢筋的损伤加剧而下降,且钢筋损伤速率越大,承载力下降越明显。更多还原

【Abstract】 In this paper, treating the concrete reinforced continuous beam as the subject, cellular automata was applied in simulating the temperature diffusion evolution for its cross section under fire, then damage factors of steel bars at different heating-up time are obtained. It’s shown that the temperature at the cross section rise gradually with time increasing, and the closer to the boundary with fire, the higher the temperature is, and the temperature at the corner of both sides near the fire is highest. And the damage of steel bars aggravate when the heating-up time increase, and the closer to the boundary with fire, the greater the damage rate of steel bars. Moreover, taking into account the non-linearity, based on the theory of fiber model, damage factors are introduced to modify the section stiffness matrix, and then the nonlinear analysis for the reinforced concrete beam under fire is implemented. The results show the deflection at mid-span of the beam increase while the heating-up time increasing, and the deformation become greater since non-linearity is considered. Besides, when the damage of the steel bar in the tensile area exacerbating, the bearing capacity of the section at the key point is on the decline, and the larger the damage rate, the more obvious the bearing capacity decreases.更多还原