BRIEF ORIGINAL Glued-in rods in beech laminated veneer lumber M. Stepinac 1 • V. Rajc ˇic ´ 1 • F. Hunger 2 • J. W. G. van de Kuilen 2 Received: 13 February 2015 Ó Springer-Verlag Berlin Heidelberg 2016 Abstract Beech laminated veneer lumber is a new engineered wood product with superior mechanical prop- erties and high density. In order to take advantage of this superior mechanical performance in the case of connec- tions with glued-in rods a series of pull compression tests with different angles to the grain have been performed applying both polyurethane and epoxy resin as adhesives. No influence of the grain angle on the load carrying capacity could be found. In addition, a survey on design rules and their acceptance in practice has been carried out, showing a clear need for further standardization. 1 Introduction Glued-in rods (GiR) have been used for several decades in timber structures to transfer forces from one member to another. Furthermore they have been applied as a rein- forcement of timber members loaded in tension perpen- dicular to the grain. They are also used in heavy timber constructions where joints with a high load capacity are needed. They represent a versatile joint system with advantages of high load transition, appropriate behavior in case of fire, easy application combined with a high level of prefabrication for fast installation. Moreover, what cannot be neglected is the aesthetic appearance of the finished joint (Stepinac et al. 2013). The work described in this paper was conducted at Holzforschung Mu ¨nchen, Germany, in January 2013 as part of the Short Term Scientific Mission (STSM) of COST Action FP1004 ‘‘Enhance mechanical properties of timber, engineered wood products and timber structures’’. STSM was obtained in three phases. In the first phase state of the art in glued-in rods was examined and comparison between different design approaches of such systems was obtained. In addition to the comparison of design rules, in the second phase, an online survey on the usage, requirements for a design rule and scientific research was developed and sent to scientists, timber industrialists and structural designers all over Europe. In the final stage of STSM, pull-com- pression tests of GiR in laminated veneer lumber (LVL) were obtained. LVL made of European beech is a new product on the market and it would be interesting to analyse the performance of GiR in beech LVL timber frames. The first part of this paper was used for the conference paper (Stepinac et al. 2013) and the second part formed the basis of a scientific article (Hunger et al. 2016). 2 State of the art and comparison of design rules for GiR One outcome of the discussion within the COST Action FP 1004 was to gather relevant information from published articles and known design rules and try to find out what needs exist and what hinders the introduction of design rules for GiR in Eurocode 5 family of standards. The idea was to focus all research knowledge and experiences (GIROD, Licons, etc.) to point out key issues regarding glued-in rods that need to be resolved. Briefly, what was concluded from past researches is that pull-out strength & M. Stepinac mstepinac@grad.hr 1 Faculty of Civil Engineering, University of Zagreb, Zagreb, Croatia 2 Technische Universita ¨t Mu ¨nchen, Holzforschung Mu ¨nchen, Germany 123 Eur. J. Wood Prod. DOI 10.1007/s00107-016-1037-y