Study on a newly developed diagonal connection for hybrid timber trusses made of spruce glulam and beech laminated veneer lumber

Abstract

The paper presents a truss concept characterised by structural simplicity and economic efficiency. The intended materials are spruce glulam for chords as well as posts and beech LVL (laminated veneer lumber) for diagonals, which are stressed in tension. Connections between the truss members are preferably be realised using self-tapping screws. The main focus of the paper is on a newly developed diagonal connection where the diagonals are screwed on to both outsides of the chords with countersunk screws and special washers. For this diagonal connection, a calculation model of the load-bearing capacity and the connection stiffness is presented. Tests were performed which encompass local and global stiffness examinations between screwed-on beech LVL diagonals and chords even for technically different screw connections. The corresponding test results agree with analytical values according to the proposed calculation model. A corresponding small-scale truss prototype was designed and tested. Computer-aided analyses of the truss deformations give first evidence for the actual feasibility of the truss concept employing the newly developed connection.

Calibration of Electrical Resistance to Moisture Content for Beech Laminated Veneer Lumber “BauBuche S” and “BauBuche Q”

“…However, this is not the case for some of the novel engineered wood products that are nowadays increasingly used in timber structures. Specifically, one of these products is beech laminated veneer lumber (LVL), and under the product name "BauBuche" [6] as it is known in Europe, it is already widely used and characterized for diverse innovative structural applications [7][8][9][10][11][12][13][14]. However, studies on the physical properties of "BauBuche" or beech LVL are still relatively sparse, with only a few studies having assessed moisture-related properties [15], or the influence of processing, raw material variability, or modification treatments on some physical and mechanical properties [16][17][18][19].…”

Calibration and comparison of two moisture content measurement methods for in situ monitoring of beech laminated veneer lumber

“…Owing to the high degree of homogenization and additional densification of the beech veneer plies, beech LVL (Pollmeier Baubuche) is known for its high load-bearing capacity (Pollmeier 2021a). In addition, this wood product is suitable for load-bearing elements in applications requiring high load-bearing capacity with small cross-sections, especially when axial loading is involved (Steige and Frese 2019). Moreover, it is graded as the strength class GL75, which is three times stronger than common GL24 softwood-glued laminated timber.…”