考虑木材燃烧效应的大空间体育馆木结构建筑火场升温模型研究

Study on analytical model of temperature development of large-space gymnasium timber structure buildings considering wood combustion effects

木结构建筑因具有美观环保的特点被越来越多的建筑设计师所采用,更多建筑形式优雅、结构受力可靠的大空间木结构建筑被设计出来。然而,木材作为一种易燃材料,在经历火场高温后会发生复杂的物理化学反应,热解会导致其力学性能的退化,且大空间火灾的升温情况与普通室内火灾有所不同,这阻碍了木结构建筑的推广应用。参考大空间建筑火灾的经验公式形式,建立了适合大空间木结构建筑的多点火源燃烧火场升温分析模型。基于火灾模拟软件FDS进行有限元建模,分析在木材燃烧效应下大空间木结构建筑内火场升温状态,研究建筑面积、建筑高度、火源功率等因素对于大空间火场升温的影响。研究结果表明,当建筑面积越大、建筑高度越高、火源功率越大时,火场的最高升温就越大,且大空间建筑内的顶棚区域是火灾最为严重的区域。经对比,所提出的大空间木结构建筑火灾升温曲线可满足结构设计过程中的安全性、经济性和适用性要求,为今后大空间木结构建筑的防火研究打下坚实的基础,并为后期木构件建筑温度场的分析提供理论依据。

A great deal of large-space timber structure buildings was designed because of its elegant architectural forms and reliable structural strength.However,its further promotion and application was blocked because of its combustibility.After experiencing the high temperature of the fire field,complex physical and chemical reactions will occur in wood,and its mechanical properties will be reduced due to pyrolysis.The temperature rose in large space fire was different from that in ordinary indoors.Referred to the empirical formula of fire in large-space building,the fire temperature rose formula for large space timber buildings with multiple ignition sources was proposed.Finite element models were established by the fire simulation software FDS.The temperature rose in large space timber structure buildings was analyzed under the effect of wood combustion.The influence of building area,building height,fire source power and other factors on the air temperature of large-scale fires were studied.It was concluded that the proposed fire rising temperature curve of the large space timber structure could meet the requirements of safety,economy and applicability in the structural design process.It laid a solid foundation for the fire proof research of large space timber structures and provided theoretical basis of further analysis.