The Usefulness of Pine Timber (Pinus sylvestris L.) for the Production of Structural Elements. Part II: Strength Properties of Glued Laminated Timber

Abstract

The paper assessed the feasibility of manufacturing glued structural elements made of pine wood after grading it mechanically in a horizontal arrangement. It was assumed that the pine wood was not free of defects and that the outer lamellas would also be visually inspected. This would result in only rejecting items with large, rotten knots. Beams of the assumed grades GL32c, GL28c and GL24c were made of the examined pine wood. Our study indicated that the expected modulus of elasticity in bending was largely maintained by the designed beam models but that their strength was connected with the quality of the respective lamellas, rather than with their modulus of elasticity. On average, the bending strength of the beams was 44.6 MPa. The cause of their destruction was the individual technical quality of a given item of timber, which was loosely related to its modulus of elasticity, assessed in a bending test. Although the modulus of elasticity of the manufactured beam types differed quite significantly (11.45–14.08 kN/mm2), the bending strength for all types was similar. Significant differences occurred only during a more detailed analysis because lower classes were characterized by a greater variation of the bending strength. In this case, beams with a strength of 24 MPa to 50 MPa appeared.

Strength Properties of Structural Glulam Manufactured from Pine (Pinus sylvestris L.) Side Boards

“…Beams were manufactured in the symmetrical system, i.e., with 4 pieces from each grade. Assuming that KW timber is characterised by the modulus of elasticity of 12 kN/mm 2 , KS 11 kN/mm 2 and KG 9 kN/mm 2 (EN 338 [ 37 ]) and applying the known Equation (2) [ 14 ]: where:…”

“…In the EU countries many tree and wood species, both hardwood and softwood, have been tested and graded, while their suitability for the manufacture of solid structural glulam has also been assessed. This has been done, e.g., for Douglas fir originating from Ireland and the United Kingdom [ 7 , 8 ] and Germany [ 9 ], pine [ 10 , 11 , 12 , 13 , 14 ] and other softwood species [ 15 , 16 ] growing in Poland [ 10 , 17 ], while in the case of non-European countries it was, e.g., ponderosa pine from the USA [ 18 ], maple [ 19 ], black spruce from Canada [ 20 ], acacia from Indonesia [ 21 ] and Japanese larch [ 22 , 23 ]. Glulam beams may be manufactured from lamellas bonded horizontally or vertically.…”

“…The applied conversion method was consistent with the practice adopted in Poland for structural timber. Those researchers also tested bonded beams manufactured from pine sawn timber [ 14 ]. In one of their studies [ 12 ], they presented, e.g., strength classification of sawn timber, while another paper [ 13 ] compared sawn timber strength grades according to national and EU standards.…”

Evaluation of Wood Composite Sandwich Panels as a Promising Renewable Building Material

“…EWPs such as laminated veneer lumber (LVL), plywood, oriented strand board (OSB), and mass timber products such as glue-laminated timber (Glulam), cross laminated timber (CLT), and structural composite lumber (SCL) that are used in building construction have been around for decades, for instance. Since the application of mass timber products in the construction of tall buildings is of interest to the industry and the research community these days, several studies have evaluated different aspects of these products [ 13 , 14 , 15 ]. Additionally, limited work has been conducted on developing wood-based composite sandwich panels with three-dimensional cores for use in building envelopes.…”

Rotational Stiffness and Carrying Capacity of Timber Frame Corners with Dowel Type Connections

“…Wood is an important building material that can be used in all applications of construction tasks. However, in some respects, it requires specific approaches, such as testing of mechanical properties and classification [ 1 , 2 ]. It is also possible to use specific dynamic testing [ 3 ] or the vibration acoustic method [ 4 ].…”