高强混凝土剪力墙耐火极限的精细模拟与计算  

Simulation and calculation study on fire resistance limit of high strength concrete shear wall

作　　者：王安涟 陈菁 刘雁[1] 张玲峰 Wang Anlian;Chen Jing;Liu Yan;Zhang Lingfeng(College of Civil Science and Engineering,Yangzhou University,Yangzhou 225127,China)

机构地区：[1]扬州大学建筑科学与工程学院,江苏扬州225127

出　　处：《建筑科学》2023年第7期37-46,共10页Building Science

基　　金：国家自然科学基金(52108253)。

摘　　要：本文对高强混凝土剪力墙在火灾下真实行为建立精细化数值模型,通过建立温度场模型,对受热响应进行对比验证,分析迎火面对流传热系数、综合辐射系数、混凝土含水率等对温度场的影响;建立顺序热力耦合模型,对结构响应进行对比验证,对混凝土强度、保护层厚度、钢筋强度和配筋率进行参数分析,以此研究高强混凝土剪力墙在火灾下平面外变形及耐火极限;基于荷载水平判定准则和温度场计算结果,推导出高强混凝土剪力墙耐火极限计算方法,该方法计算值与有限元模拟结果吻合良好。分析表明:增大对流传热系数对极限温度影响不大;增大综合辐射系数,迎火面附近温度显著增加;增大混凝土含水率对迎火面附近温度影响极小,但对背火面附近温度提升显著。增大混凝土强度,高强混凝土剪力墙平面外变形减小,其耐火极限得到提高;合理增大保护层厚度可以有效提高构件的耐火极限。在耐火等级为一级、二级、三级时,混凝土保护层厚度建议分别取30mm、25mm、15mm;钢筋强度对墙体耐火极限几乎没有影响;高强混凝土剪力墙配筋率越大,耐火极限显著降低。该文提出的耐火极限计算方法对高强混凝土剪力墙的耐火设计提供了支撑。In this paper,the fine numerical model is established for the real behavior of high⁃strength⁃concrete shear wall under fire.By establishing temperature field model,the thermal response is compared and verified,and the effects of heat transfer coefficient,comprehensive radiation coefficient and concrete moisture content on the temperature field are studied.A sequential thermal⁃mechanical coupling model is established to verify the structural response,and the concrete strength,protective layer thickness,reinforcement strength and reinforcement ratio are analyzed to study the out⁃of⁃plane deformation and fire resistance of high⁃strength⁃concrete shear wall under fire.Based on the criterion of load level and the result of temperature field calculation,the calculation method of fire resistance is deduced.The results show that the out⁃of⁃plane deformation of high⁃strength concrete shear wall decreases and its fire resistance increases with the increase of concrete strength.Reasonably increasing the cover thickness can effectively improve the fire resistance of components.It is suggested that the cover thickness should be 30mm,25mm and 15mm when the fire resistance level is first,second and third,respectively.The strength of reinforcement has little effect on the fire resistance.With the increase of reinforcement ratio,the fire resistance of high⁃strength⁃concrete shear wall decreases significantly.The calculation method of fire resistance proposed in this paper provides support for fire resistance design of high⁃strength⁃concrete shear wall.

关 键 词：高强混凝土剪力墙 数值模型 参数分析 耐火极限 

分 类 号：TU37[建筑科学—结构工程]