Scheibenschub von Brettsperrholz: Verifizierung einer Prüfkonfiguration und Parameterstudie

Abstract

Shear properties of cross laminated timber diaphragms: verification of a test configuration and parameter studyIn diaphragms of cross laminated timber (CLT) exposed to shear the internal structure of orthogonally layered side bonded layers leads to three possible failure mechanisms: (i) grossshear, (ii) net-shear and (iii) torsion. While the resistance against torsion has been investigated comprehensively, the determination of gross-and net-shear strength values remained a challenging task. Present design concepts for net-shear are based on properties derived from testing single CLT-nodes. The verification of this approach for CLT-elements has yet to be confirmed. This article aims to verify the applicability of the test configuration published 2013 by KREUZINGER and SIEDER [1]. Therefore and for evaluation of shear properties relevant for design, 18 series featuring different parameter settings were tested. In doing so, the operational efficiency of the new shear test configuration together with reliable shear failure of all tested CLT diaphragms was observed. With regard to the investigated parameters, results qualitatively correspond with tests on single CLT-nodes. Gap execution and layer thickness are confirmed to be parameters significantly influencing shear properties. Based on gathered experiences, characteristic shear properties and a design concept are proposed. Bautechnik 92 (2015), Heft 11 R. Brandner, P. Dietsch, J. Dröscher, M. Schulte-Wrede, M. Sieder: Scheibenschub von Brettsperrholz: Verifizierung einer Prüfkonfiguration und Parameterstudie

Experimental Investigation of Cross Laminated Timber Elements with Holes or Notches at In-Plane Beam Loading Conditions

“…A single characteristic value of f v,gross,k = 3.50 MPa was suggested in [3], considering shrinkage cracks by reducing the thickness of exterior layers by 50% when determining t gross . For net shear failure (FM II), the determination of net shear strength is not so straightforward, see [23][24][25], and no values for the strength class of the laminations were provided in EN 338 [22]. Based on the most recent comprehensive experimental study [3], a conservative reference net shear strength of f v,net,k,ref = 5.50 MPa is proposed for layer thicknesses t < 40 mm, while for layer thicknesses 20 < t < 40 mm, the net shear strength is provided as follows:…”

Cross-laminated timber (CLT) – a state of the art report

“…Table 2 concerns small specimens and verification of FM III, while Table 3 involves large specimens and FM II. An extensive experimental testing was conducted by Brandner et al [59] in 2015 on prisms subjected to compression load, as shown in Figure 12. Test results and varied experimental parameters are shown in Table 3.…”

“…or FM III[31,55,56]. The tests on large specimens have been oriented toward determination of FM II[57][58][59].Figure 11shows experimental setups from small models, andFigure 12shows specimens from large models. Summary…”

Beobachtungen zur Linearität der Schädigungsakkumulation im Holzbau

“…Durch eine Stauchung in Längsrichtung werden im Probekörper Schub‐ ( τ xMyM ) und Querdruckspannungen ( σ yM ) hervorgerufen (Bild mittig), sodass eine Prüfung der Schubtragfähigkeit unter Vorhandensein einer zusätzlichen Querdruckbeanspruchung erfolgt. Da die Interaktionsbeziehung zwischen Schubfestigkeit und Querdruckbeanspruchung bekannt ist , kann eine Bereinigung der beobachteten Schubtragfähigkeiten um den (günstigen) Einfluss der Querdruckbeanspruchung erfolgen . Die Eignung des gewählten Prüfverfahrens, das ursprünglich für die Ermittlung von Eigenschaften unter quasistatischer Beanspruchung entwickelt worden ist, konnte für Ermüdungsversuche im Rahmen der Versuche grundsätzlich bestätigt werden .…”