基于换算长细比的正交胶合木稳定系数计算方法  

The calculation method of stability coefficient of CLT members in axial compression based on the effective slenderness ratio

作　　者：武国芳[1] 钟永[1] 龚迎春[1] 任海青[1] WU Guofang;ZHONG Yong;GONG Yingchun;REN Haiqing(Research Institute of Wood Industry,Chinese Academy of Forestry,Beijing 100090,China)

机构地区：[1]中国林业科学研究院木材工业研究所,北京100090

出　　处：《林业工程学报》2022年第1期59-65,共7页Journal of Forestry Engineering

基　　金：国家自然科学基金青年科学基金(51808546)。

摘　　要：正交胶合木(CLT)纵横向层板交叉组坯,纵向层板强度和模量较高,横向层板强度和模量较低,其截面呈强弱相间的条带状结构。当轴心受压构件失稳时,截面剪切变形对CLT稳定承载力的影响不可忽略,故不能采用一般木产品的稳定承载力计算方法。目前我国相关标准中尚无CLT轴心受压构件稳定承载力计算方法。鉴于此,从CLT产品的截面构成特点出发,将其视为分肢柱:纵向层板视作柱肢,横向层板视作柱肢之间的连接。采用考虑剪切变形的压杆屈曲理论,首先计算不考虑横向层板时的构件长细比,再考虑横向层剪切变形对长细比的影响,推导建立了CLT的换算长细比计算式,并将其与GB 50005—2017《木结构设计标准》中的稳定系数计算式相结合,提出了CLT轴心受压构件稳定系数计算方法。经比较,发现提出的计算方法与试验结果吻合较好。通过与主要国家制定的稳定承载力计算方法进行比较,发现所提出的方法计算结果高于日本方法,与欧洲及美国方法所计算的稳定系数基本一致,验证了本研究所提出方法的准确性和可行性,可为CLT的设计和工程应用提供依据。Cross-laminated timber(CLT)panel consists of several layers of laminations stacked in alternating directions,bonded with structural adhesives,and pressed to form a solid,straight,rectangular panel.The number of laminations is usually odd.CLT panel is relatively a new engineered wood product that can be used as load bearing members such as walls,beams,floors and roof elements in modern timber structures.As a new type of product,the design methods of CLT are still not been fully developed.In the cross section of CLT,the longitudinal laminations are stronger than the transverse laminations both in elastic modulus and strength.There is shear stress in the cross section of members when they are buckled in axial compression.The shear stress will induce sufficient large shear deformation in the cross section,because the shear modulus of the transverse lamination is rather small.The contribution to the buckling capacity of shear deformation of the transverse laminations is unneglectable.The calculation method of stability coefficient for general wood products has been established,however,the shear deformation was not considered in the available method,which is not suitable for CLT.Furthermore,the calculation method of the buckling capacity of the cross-laminated timber(CLT)in axial compression has not been established yet in China.In view of this,CLT was treated as built-up column,where the longitudinal laminations were as limbs and the transverse laminations were as imaginary fasteners connecting the limbs,based on the specific formation of the cross-section.To calculate the stability capacity of CLT,firstly,the slenderness ratio of the member without considering the contribution of transverse lamination was calculated,then the effect of the transverse lamination was considered based on mechanics.Then the effective slenderness ratio was derived by the buckling theory considering shear deformation effect,and the stability coefficient of CLT could be obtained by substituting the effective slenderness ratio into the equati

关 键 词：木结构 正交胶合木 稳定系数 换算长细比 轴心受压构件 稳定承载力 

分 类 号：TU366.2[建筑科学—结构工程]