大跨度木桁架屋盖考虑屋面板刚度的简化设计方法

A simplified design method of long span wood truss roof considering roof panel stiffness

随着社会发展,一些大跨度木结构由于某些特殊要求,无法设置水平支撑等措施保障其整体稳定性。基于二维分析方法设计的木桁架,屋面板一般只作为荷载施加至结构上。由于屋面板覆盖的轻型搁栅及定向刨花板,其平面内刚度类似于轻木结构剪力墙,通过相关规范和受力分析,根据轻型搁栅及定向刨花板的几何尺寸和构造措施简化了其刚度,并考虑了它对结构的有利作用。然后通过SAP2000进行有限元模拟,发现考虑屋面板刚度后,最不利位置处的位移减小了83%,简化后位移误差最大为23%,但此误差对设计有利并且其层间位移角仍满足规范要求。刚度简化方法建模相对简单,对屋面板刚度直接用弹簧刚度的方式进行量化,可为设计提供便利并为类似工程项目提供借鉴思路。

With the development of society,some large-span timber structures cannot be provided with horizontal support and other measures to ensure their overall stability due to some special requirements.For wood trusses designed based on two-dimensional analysis method,the roof panel is generally applied to the structure as a load.Because the light joist and OSB covered by the roof panel are similar to the shear wall of light wood structure in plane stiffness,this paper simplifies their stiffness according to the geometric dimensions and structural measures of light joist and OSB through relevant specifications and stress analysis,and considers their beneficial effects on the structure.Then the finite element simulation is carried out through SAP2000.It is found that the displacement at the most unfavorable position is reduced by 83%after considering the roof panel stiffness,and the maximum displacement error after simplification is 23%,but this error is beneficial to the design and the inter story displacement angle still meets the requirements of the code.The stiffness simplification method is relatively simple in modeling.The stiffness of the roof panel is directly quantified by spring stiffness,which can provide convenience for design and reference ideas for similar projects.