摘要
为研究波形钢腹板-钢底板组合箱梁在火灾作用下的挠变规律及耐火极限,本研究以一试验梁为研究背景,采用有限元软件ANSYS建立波形钢腹板-钢底板组合箱梁数值模型开展热-力耦合分析,研究不同升温曲线、受火区域、荷载比及高跨比等因数对其耐火性能的影响。结果表明:组合箱梁钢腹板和混凝土顶板沿梁高方向存在明显的温度梯度且受火时间越长温度梯度越明显;波形钢腹板-钢底板组合箱梁跨中挠度时程曲线主要分为两个阶段,前期为缓慢增长阶段,平均增长速率1.5 mm/min,后期为快速增长阶段,平均增长速率5 mm/min;组合箱梁在HC火灾作用下的耐火极限最短,在相同荷载比作用下较ISO834标准升温曲线作用下的耐火极限下降了71.8%;组合箱梁受火区域越大,耐火极限越小,且受火区域越靠近跨中截面,耐火极限越小;荷载比对组合箱梁的抗火性能有较大影响,荷载比由0.2增长到0.4时,组合箱梁的耐火极限降低了40.4%;高跨比越大的组合箱梁,虽然受火前期的耐火性能有明显的提高,但是后期随着温度的不断升高其耐火极限反而小于高跨比小的组合箱梁,且随着组合箱梁的高跨比从0.088增长到0.147,其耐火极限降低了23.1%。研究成果可为波形钢腹板-钢底板组合箱梁的防火设计提供一定的参考。
In order to study the deflection variance rule and fire resistance of composite box girder with corrugated steel web and steel bottom under fire,taking a test beam as the study background,and using finite element software ANSYS to establish a numerical model of composite box girder with corrugated steel web and bottom for carrying out thermal and mechanical coupling analysis.The the influences of different temperature curve,fire area,load ratio and height span ratio on fire resistance are studied.The result shows that(1)the temperature gradient of steel web and concrete roof of composite box girder is obvious along the beam height direction,and the temperature gradient becomes more obvious with longer fire time;(2)the mid-span deflection time history curve of the composite box girder with corrugated steel web and steel bottom plate is mainly divided into 2 stages,the early stage is a slow growth stage with an average growth rate of 1.5 mm/min,and the late stage is a rapid growth stage with an average growth rate of 5 mm/min;(3)the fire resistance of the composite box girder under HC fire is the shortest,and the fire resistance of the composite box girder under the influence of standard ISO834 heating curve under the same load ratio decreases by 71.8%;(4)the larger the fire area is,the smaller the fire resistance is,the closer the fire area is to the mid-span section,and the smaller the fire-resistance is;(5)the load ratio has great influence on the fire resistance of the composite box girder when the load ratio increases from 0.2 to 0.4,and the fireresistance of the composite box girder decreases by 40.4%;(6)although the fire resistant performance of the composite box girder with a larger high-span ratio is improved in the early stage of fire obviously,the fireresistant limit is smaller than that of the composite box girder with a smaller high-span ratio as the temperature continues to rise in the later stage,and the fire-resistant limit decreases by 23.1%as the high-span ratio of the composite box girder increas
作者
郑尚敏
管冲
ZHENG Shang-min;GUAN Chong(School of Civil Engineering and Architecture,East China Jiaotong University,Nanchang,Jiangxi 330013,China)
出处
《公路交通科技》
CAS
CSCD
北大核心
2024年第3期94-101,共8页
Journal of Highway and Transportation Research and Development
基金
国家自然科学基金项目(52068025)。
关键词
桥梁工程
耐火性能
数值模拟
波形钢腹板
挠变规律
耐火极限
bridge engineering
fire resistance
numerical simulation
corrugated steel web
deflection variance rule
fire-resistant limit
