摘要
为揭示约束混凝土梁的升降温全过程火灾行为,开展了8根约束梁的明火试验,考察了升降温作用下梁端轴向和转动约束、荷载比、升温时间等参数对约束梁高温变形及内力的影响。试验结果表明:1)升降温过程中试件轴力呈现出先较快增大而后逐渐减小并渐趋平缓的趋势,降温结束后仍存在明显的残余轴压力,试验过程中各试件的最大轴力比约0.05―0.1;2)升温时间对试件左、右两端弯矩最大值的平均值影响有限,即该最大值的平均值基本上在升温60min内就已达到;3)转动约束刚度比改变对试件左、右两端附加弯矩最大值的平均值影响不大。
In order to investigate the fire behaviors of reinforced concrete（RC） restrained beams during heating and cooling phases,eight restrained RC beams were tested in fire with a cooling phase.The influences of some parameters（such as axial/rotational restraint stiffness,load ratio,and heating time） on deformations and internal forces of the restrained beams were discussed.Test results show that： 1） the axial force in restrained beam subjected to heating and cooling processes increases first and then drops gradually;the residual axial force is significant after the cooling phase,and the maximum axial force ratios of the specimens are range from 0.05 to 0.1;2） the influence of heating time on the mean value of maximum bending moments at the left and right beam ends is limited,implying that the mean value of maximum bending moments reaches within 60 min of heating;and 3） the change of rotational restraint stiffness has little effect on the mean value of maximum additional bending moments at the left and right beam ends.
出处
《工程力学》
EI
CSCD
北大核心
2011年第6期88-95,共8页
Engineering Mechanics
基金
国家自然科学基金重点项目(50738005)
国家杰出青年科学基金项目(51025829)
教育部科技重点项目(108106)
国家科技支撑计划子课题项目(2006BAJ03A03-12)
亚热带建筑科学国家重点实验室重点研究项目(2008ZA10)
关键词
钢筋混凝土
约束梁
耐火试验
升温段
降温段
reinforced concrete
restrained beam
fire resistance experiment
heating phase
cooling phase
