This paper presents the results of extensive investigations on the lamination strength grading, the production and the mechanical properties of European beech (Fagus sylvatica L.) glued laminated timber (GLT). Based on the analysis of potential influencing parameters on strength and stiffness as well as subsequent tension tests parallel to the grain on single boards, a combined visual/machine approach for grading the raw material into tensile strength classes T50, T42, T33 and T22 was developed. Boards strength graded with the developed procedure were then finger-jointed by a Swiss GLT producer and the strength of the finger joints was investigated by means of tension and bending tests. The strength and durability of the bonding was investigated and verified by means of tensile-shear and delamination tests. It could be shown that the required finger-joint and bondline strengths for GLT of strength classes GL40 and GL48 can be achieved, but that the process parameters for finger jointing (in particular the geometrical properties of the finger joint profile) have to be optimized in order to be able to produce GLT of strength class GL55. Finally, an extensive experimental testing campaign was performed to investigate the mechanical properties of European beech GLT produced based on the strength grading rules and production techniques developed before. Bending, tensile and compressive parallel to the grain, as well as shear tests were carried out on GLT specimens of strength classes GL40, GL48 and GL55 in different sizes in terms of cross-section and length. Based on these investigations and complementing numerical simulations, characteristic strength and stiffness values and formulae for consideration of size effects in bending, tension and shear were determined.

本文介绍了对欧洲山毛榉（Fagus sylvatica）的层压强度等级，生产和力学性能进行广泛研究的结果。L.）胶合层压木材（GLT）。基于对强度和刚度的潜在影响参数分析，以及随后在单板上进行平行于谷物的拉伸测试，开发了一种组合的视觉/机器方法，将原材料分为拉伸强度等级T50，T42，T33和T22 。然后，由瑞士GLT生产商用指接的方法对按照开发程序分级的木板强度进行指接，并通过拉伸和弯曲试验研究指接的强度。通过拉伸剪切和分层测试研究并验证了粘合的强度和耐久性。可以证明，可以达到强度等级GL40和GL48的GLT所需的指接和粘接强度，但是必须优化用于手指接合的工艺参数（尤其是手指接合轮廓的几何特性），以便能够生产强度等级为GL55的GLT。最后，进行了广泛的实验测试活动，以基于以前开发的强度分级规则和生产技术来研究生产的欧洲山毛榉GLT的机械性能。平行于晶粒的弯曲，拉伸和压缩以及剪切试验是在强度等级GL40，GL48和GL55的GLT试样上进行的，这些试样的横截面和长度均不同。基于这些研究和补充的数值模拟，确定了特征强度和刚度值以及考虑弯曲，拉伸和剪切尺寸效应的公式。