考虑蠕变的约束钢梁简化抗火设计方法  

Simple Fire-resistance Design Method of Restrained Steel Beam Considering Creep Effect

作　　者：李现辉 何平召 王卫永[2] LI Xianhui HE Pingzhao WANG Weiyong(Henan Urban Construction Consultant CO. , Ltd. , Zhengzhou 450008, China School of Civil Engineering, Chongqing University, Chongqing 400045, China)

机构地区：[1]河南城市建筑咨询有限公司,河南郑州450008 [2]重庆大学土木工程学院,重庆400045

出　　处：《防灾减灾工程学报》2016年第4期633-639,共7页Journal of Disaster Prevention and Mitigation Engineering

基　　金：中央高校基本科研业务费项目(CDJZR12200004);重庆市自然科学基金项目(cstc2013jcyjA30010)资助

摘　　要：高温荷载作用下钢材产生明显的蠕变变形,对钢结构在火灾下的变形和受力性能产生较大的影响。为定量确定高温蠕变对约束钢梁抗火承载力的影响,利用ANSYS建立了考虑蠕变的约束钢梁有限元分析模型。与试验数据对比发现:仅仅通过应力应变关系考虑蠕变不能较好地模拟约束钢梁中蠕变的发展,而采用Poh模型的应力应变关系并考虑蠕变与试验数据吻合最好。利用验证后的分析模型进行参数分析,发现转动约束刚度、屈服强度、升温速率和跨高比等都对约束钢梁的临界温度有明显的影响。《建筑钢结构防火技术规范》给出的约束钢梁抗火设计方法未充分考虑这些参数的影响。对参数分析的结果进行回归分析,给出了适用的考虑蠕变的约束钢梁抗火简化计算方法。Significant creep deformation occurs in steel subjected to high temperature and load action,and has important effect on the deformation and load bearing capacity of steel beams in fire.In order to quantify the influence of creep at elevated temperatures on load bearing capacity of restrained steel beams,finite element analysis model for restrained steel beam was established in ANSYS by taking creep into consideration.Comparison with test data shows that using the curves of stress-strain relation to consider creep can＇t simulate the creep in restrained steel beam.The best agreement was found between analytical results using Poh model of stress-strain curves considering creep and test data.Parametric study was conducted by employing the validated model.The study indicated that the variation of rotational restraint stiffness,yield strength,heating rate and span-depth ratio et al have an obvious influence on critical temperature.Those parameters above are not considered in current fire resistance design standard on restrained steel beam.By doing regression analysis of the results of parametric study,a simplified calculating method is presented to calculate fire resistance of restrained steel beam considering creep effect.

关 键 词：蠕变 约束钢梁 简化设计 抗火 

分 类 号：TU392[建筑科学—结构工程]