有单(双)向面内约束力混凝土板火灾行为机理分析  

Mechanism analysis of fire behavior of concrete slabs subject to uni-axial(bi-axial) in-plane restraint

作　　者：王勇[1,2] 马帅[1] 史伟男 张亚军[1] 段亚昆[1] 袁广林 Wang Yong;Ma Shuai;Shi Weinan;Zhanng Yajun;Duan Yakun;Yuan Guanglin(Jiangsu Key Laboratory of Environmental Impact and Structural Safety in Engineering,China University of Mining & Technology,Xuzhou 221008 China;State Key Laboratory for Geomechanics and Deep Underground Engineering,China University of Mining & Technology,Xuzhou 221008,China;JiangSu Collaborative Innovation Center for Building Energy Saving and Construct Technology,Xuzhou 221008,China)

机构地区：[1]中国矿业大学江苏省土木工程环境灾变与结构可靠性重点实验室,江苏徐州221008 [2]中国矿业大学深部岩土力学与地下工程国家重点试验室,江苏徐州221008 [3]江苏建筑节能与建造技术协同创新中心,江苏徐州221008

出　　处：《土木工程学报》2019年第2期32-43,共12页China Civil Engineering Journal

基　　金：国家青年自然科学基金(51408594);中国博士后科学基金(2018QNB10);中国博士后科学基金特别资助(2016T90525);中央高校基本科研业务费专项基金(2014QNA78);江苏建筑节能与建造技术协同创新中心资助(SJXTQ1614);国家级大学生创新创业训练计划基金(201610290008)

摘　　要：为考查面内约束作用对混凝土双向板火灾行为影响,对八块面内约束混凝土试验板进行数值模拟和对比分析,研究了几何(非)线性和混凝土膨胀应变对约束试验板变形、弯矩分布和薄膜机理影响规律。同时,开展参数分析,研究约束类型、约束水平、长宽比、配筋率和板厚等对面内约束混凝土板温度场、变形、破坏模式和耐火极限等影响。结果表明,对任一约束工况,较大混凝土膨胀应变导致约束板较大变形,且几何非线性影响不可忽略;面内约束作用倾向于降低跨中弯矩和增大板边负弯矩,且不利于板大变形阶段受拉薄膜效应发展;约束板火灾行为取决于约束类型、约束水平和长宽比等相互作用;增加板厚和配筋率有助于提高约束板抗火性能。To investigate the effect of the in-plane restraint on the fire behavior of concrete slabs,the numerical analysis of eight in-plane restrained concrete slabs were conducted.The influence of the geometrical nonlinearity (linearity)and concrete thermal strains on the deflection,bending distribution and membrane actions were investigated.Meanwhile,the parametrical analysis was conducted to investigate the effect of the restraint type, restraint level,aspect ratio,reinforcement ratio and thickness on the temperature,deflection,failure mode and fire resistance of the restrained slabs.The research results indicate that for any restraint condition,larger concrete thermal strains result in larger deflections of the restrained slabs,and the geometrical nonlinearity should be considered in the numerical analysis.In addition,the in-plane restraint will lead to lower mid-span moments and larger negative moments,which is not beneficial to the tensile membrane action development of concrete slabs at large deflections.Fire behavior of the restrained slabs are dependent on the interaction of restraint types,restraint level and aspect ratio.It is beneficial to enhance the fire resistant performance of the restrained slabs by increasing the slabs thickness and the reinforcement ratio.

关 键 词：混凝土双向板 面内约束 数值模拟 机理分析 薄膜效应 弯矩分布 

分 类 号：TU375.2[建筑科学—结构工程]