EXPERIMENTAL INVESTIGATION OF THE STRENGTH OF CROSS-LAMINATED TIMBER

Problem statement. Cross-laminated timber (CLT) is a modern building material that can be used in the construction of buildings for various purposes. Despite its popularity abroad, CLT is still a relatively new material in Ukraine, and the current standards for designing timber structures do not include recommendations for the calculation of structures made from CLT panels. To promote the use of CLT in domestic practice, it is necessary to conduct studies on its strength characteristics in accordance with international standards. The purpose of the article is to investigate the characteristics of bending and compressive strength of domestically produced CLT through tests according to European standards. Methods. For experimental studies, samples of elements from the CLT-Result domestic manufacturer were used. The samples consisted of coniferous lumber (pine Pinus sylvestris I.) in a configuration of 3 layers 30 mm thick (CLT thickness 90 mm) and 5 layers 20 mm thick (CLT thickness 100 mm). Bending and compression tests were performed parallel and perpendicular to the plane of the longitudinal layers in accordance with the requirements of EN 16351:2021 and EN 408:2012. Conclusion. The bending strength of CLT samples is determined by the strength of the timber of the outer, most stretched layer. The destruction of the samples during bending began with the formation of cracks along the annual rings of the wood of the outer lower layer, followed by the rupture of the stretched fibers. CLT samples, when tested for compression parallel to the plane of the layers, collapsed due to the exhaustion of the bearing capacity of the timber of the longitudinal layers, which was accompanied by shearing along the inclined areas. The destruction of the CLT compressed perpendicular to the plane of the layers occurred as a result of significant compression of the wood. The following characteristics were determined: the bending strength of the 3-layer CLT panel was 15.3 MPa, and the 5-layer panel had a bending strength of 20.1 MPa; the compressive strength of the 5-layer CLT panel parallel to the plane of the layers fc,0 = 26.88…29.15 MPa, and perpendicular to the plane of the layers fc,90 = 11.16...12.13 MPa.