The aim of this study was to assess the potential of hardwoods harvested in Croatian forests for the production of glued laminated timber (glulam), mainly of those species for which there is no published performance assessment. Nine sets of glulam beams were produced: three sets using lamellas from European hornbeam, three sets from Turkey oak, and three sets from maple. Each set was characterized by a different hardwood species and surface preparation method. The surface preparation methods included planing, planing followed by sanding with fine grit, and planing followed by sanding with coarse grit. The experimental investigations included shear tests of the glue lines in dry conditions and bending tests of the glulam beams. The shear tests showed satisfactory performance of the glue lines for the Turkey oak and European hornbeam, but not for the maple. The results of the bending tests showed superior bending strength of the European hornbeam compared to the Turkey oak and maple. Planing followed by rough sanding of the lamellas was shown to have a significant influence on the bending strength and stiffness of the glulam from Turkey oak.

This paper presents the results of an experimental investigation of glued laminated timber (glulam) beams made from European hornbeam (Carpinus betulus L.) under constant loading for three months. Glulam beams were experimentally tested as a part of the last phase of the research project conducted by Drvene konstrukcije Ltd. and the Faculty of Civil Engineering, Architecture and Geodesy, Split. Beams were loaded in four-point bending tests with the applied load levels of 20% and 30% of the maximum force obtained from previously performed short-term tests. The experiments were carried out under minor environmental changes at the specialized laboratory unit at the Faculty of Civil Engineering, Architecture, and Geodesy, Split. The objective of this study is to present the research results of bending creep tests for hardwood species not included in the European Assessment Document. The experimentally obtained deflection-time curves were fitted with the power law equation used for the prediction of creep behavior. The results indicate that the power law fits well with experimental data. A comparison with requirements from Eurocode 5 is given.

U ovom radu prikazan je stohastički model za predviđanje čvrstoće na savijanje lijepljenih lameliranih greda od graba (Carpinus betulus L.) iz hrvatskih šuma. Model se temelji na 2D numeričkoj simulaciji koja kombinira softverske alate ANSYS i Matlab, s ciljem generiranja varijabilnih mehaničkih svojstava duž pojedinačnih lamela i cijelog nosača. Pri generiranju globalnih mehaničkih svojstava lamela korištene su vrijednosti dobivene vlačnim ispitivanjem lamela. Za modeliranje lokalne varijabilnosti duž lamele primijenjen je autoregresijski model prvog reda, pri čemu je uzeta u obzir kros-korelacija između modula elastičnosti i vlačne čvrstoće. Ovaj model simulira ispitivanje na savijanje lijepljenih lameliranih nosača prema normi EN 408 i pokazuje određivanje 5% fraktila čvrstoće na savijanje, a koja predstavlja karakterističnu vrijednost.