Cross Laminated Timber (CLT) Beams Loaded in Plane: Testing Stiffness and Shear Strength

New paper by Francesco Boggian, Mauro Andreolli and Roberto Tomasi on the assessment of stiffness and shear strength of CLT beams loaded in-plane.

Set up

Abstract: Cross Laminated Timber (CLT) is a relatively new timber product used in construction that has gained popularity over the last decade. The product itself is constituted by multiple glued layers of juxtaposed boards, usually arranged in an orthogonal direction between one layer and the adjacent ones. This particular structure brings several benefits, such as the possibility to use the same product both for walls and slabs, since it can bear in-plane and out-of-plane loads. However, the mechanical behavior differs from usual timber products, and research is still ongoing to achieve common agreement on standard procedures for testing products and theories for evaluating stresses for safety verifications. This paper focuses on the in-plane shear behavior of CLT and analyzes the existing methods to evaluate shear stresses. An experimental part then presents a four-point bending test of CLT beams with a specific geometry to induce shear failure. Results are reported both for the elastic range test, measuring the Modulus of Elasticity, and for the failure test to investigate shear behavior with regard to different mechanisms. Previously exposed methods are used for the calculation of shear stresses and to analyze the correspondence between them, and the results are then compared with other existing tests and values in literature. A new test setup for future research is eventually proposed.

Failure modes


Download the full paper

04/06/2019 – Ver. 74 – Improved graphical performance, automatic setting of dxf import scale, automatic definition of wind action according to Italian standard Circolare 2019 of NTC 2018 and improvement of the stability of many features

In the latest version of the software we have added the following new features:

  • Improvement of the graphical performace: it is now possible to choose whether to display the floor calculation lines and the points in the 3D graphical interface in order to obtain a clearer view of the model and an increased graphic speed in the modelling and analysis phase. This feature is very useful in the management of complex models.
  • Automatic setting of the dxf import scale: the software is now able to automatically propose the correct import scale for a dxf drawing. The user can still edit manually the proposed import scale if needed.
  • Automatic definition of the wind action according to Circolare Esplicativa 21 January 2019 of NTC 2018: in case the project uses NTC as the reference standard, the automatic calculation of the wind action on walls and roofs has been updated according to the provisions of the new Circolare Esplicativa. The software automatically proposes the values of the reference velocity pressure, of the exposure coefficient and of the aerodynamic coefficients for the walls according to the geolocation of the building and according to its shape relative to the wind directions.
  • User-defined wind pressure and/or aerodynamic coefficients in case of NTC as reference standard: it is now possible to manually edit the automatically proposed wind pressure for a specific load definition for both roofs and walls or, alternatively, it is possible to edit only the aerodynamic coefficients cp while maintaining the automatic calculation of all the other parameters required for the definition of the wind action.
  • Improvement of the stability of some features such as the milestones, the milestones with analysis and the connection auto-design.
  • Inclusion of the Knauf Diamant X sp. 15 mm panel: also the gypsum plasterboard panel for structural use Knauf Diamant X with a thickness of 15 mm is now available and it can be used as sheathing panel in framed walls.
  • Bug fixing and small improvements