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This paper investigates the mechanical and the hysteretic behaviour of steel-to-timber joints with annular-ringed shank nails in Cross-Laminated Timber (CLT). These fasteners are used to anchor typical metal connectors, such as hold-downs and angle brackets, to the CLT panels. The experimental pro- gramme presented in the paper was carried out at the Institute of Timber Engineering and Wood Technology, Graz University of Technology (Graz, Austria). Average and characteristic values of the exper- imental strength capacities are evaluated and compared to the analytical predictions determined accord- ing to current structural design codes and literature. Furthermore, to fulfil the requirements of the capacity-based design, the overstrength factor and the strength degradation factor are evaluated and con- servative values are recommended

As a product, cross-laminated timber exhibits widely linear-elastic behaviour (except for compressive stress) and a tendency to have brittle failure mechanisms. Therefore, especially at dynamic loadings (e.g. earthquakes), the behaviour of cross-laminated timber structures is highly dependent on the connections used. Based on several single-joint and wall tests performed monotonically as well as cyclically, this paper provides improved insight into the behaviour of different joints that make up cross-laminated timber structures. In addition to information on the failure modes that occurred and specific values determined by way of experimental tests, interpretations of different contributions towards the overall deflection of the tested wall systems are presented. The influence of different connection types and their combinations within one wall system is another topic discussed. Finally, the sensitivity of resulting test properties concerning the post-processing models used is singled out as a central theme.

Shaking-table tests that were performed on a three-storey cross-laminated timber structure using full-scale structural elements without vertical joints. The tests were conducted at Laboratório Nacional de Engenharia Civil in Lisbon, Portugal, under the European Union Series project. The setup, which includes the geometry, connection technique and building instrumentation that was installed to record the behaviour of the cross-laminated timber structure during the tests, and the building design are described, and the preliminary results of the earthquake tests reported. An alternative method for determining the behaviour factor q, which takes into account the results of preliminary single joint tests performed at Graz University of Technology, is discussed.

Axially loaded screws in solid timber, glued laminated timber and cross laminated timber This paper concentrates on the bearing behavior of axially loaded self-tapping screws in solid timber and the board-composed, layered timber products glued laminated timber and cross laminated timber. Focusing on withdrawal failure mode and basing on numerous investigations done in the past, we formulate a new and universal approach including multiplicative k-factors or k-functions for determining the withdrawal strength of self-tapping screws variably situated in these products. Consequently, we verify the new model with results gained from several test series related, approaches given in the literature and test results of CLT-wall-to-floor and -wall-towall connections. Finally, we determine, discuss and verify a characteristic function provided for practical application. 771A. Ringhofer, R. Brandner, G. Flatscher, G. Schickhofer: Axially loaded screws in solid timber, glued laminated timber and cross laminated timber AUFSATZ ARTICLE fach) und Steifigkeit (zwölf-bis 40-fach) einer solchen Verbindung erheblich gesteigert werden können.Im Grenzzustand der Tragfähigkeit wird nach derzeitigem Stand der Technik (ÖNORM EN 1995-1-1 [7]; Eurocode 5) das Tragvermögen von Schraubengruppen bei axialer Zugbeanspruchung aus dem Minimum der Versagensmechanismen "Stahlbruch des Schraubenquerschnitts" (inkl. Kopfabreißen), "Herausziehen des Gewindes", "Kopfdurchziehen" und "Blockscheren der Verbindung" ermittelt. Mit Fokus auf das Tragverhalten der Einzelschraube (das Gruppentragverhalten wurde u. a. in MAHLKNECHT und BRANDNER [8] bzw. in PLÜSS und BRANDNER [9] behandelt) und aufgrund dessen Stellenwertes unter allen möglichen Versagensmechanismen wird der Versagensmechanismus "Herausziehen" für BSP-Schraubenverbindungen im Rahmen dieses Aufsatzes näher betrachtet.In der Vergangenheit wurde "Herausziehen" als Verbundversagen des im Holz eingebrachten Schraubengewindes speziell für Vollholz bereits umfassend untersucht (siehe u. a. BLASS et al. [10], PIRNBACHER et al. [11], FRESE und BLASS [12] und HÜBNER [13]) und mittels empirischer Regressionsmodelle für eine große Bandbreite variierender Einflussparameter (Durchmesser, Eindrehwinkel, Rohdichte, Holzart, etc.) Bautechnik 92 (2015), Heft 11 773A. Ringhofer, R. Brandner, G. Flatscher, G. Schickhofer: Axially loaded screws in solid timber, glued laminated timber and cross laminated timber AUFSATZ ARTICLE MethodenSämtliche in Tab Potenzparameter k ρ zur Berücksichtigung des Rohdichteeinflusses auf die Verschraubung in der EinzelschichtWie in Gl. (2) Funktion k ax zur Berücksichtigung des Winkel-und FugeneinflussesAufgrund der Tatsache, dass zwischen der Fugenverschraubung und dem Eindrehwinkel ein signifikanter Zu- In der Betrachtung wurde der gesamte, für eine Verschraubung zulässige Querschnittsbereich, also abzüglich des Mindestrandabstandes a 2,c = 5d ( angegebenen Ansatz hergeleitet (Gl. (11)).