Influence of Wooden Board Strength Class on the Performance of Cross‐laminated Timber Plates Investigated by Means of Full‐field Deformation Measurements

Abstract

Although cross-laminated timber (CLT) plates are increasingly used in high-performance building structures, a tailored composition of them or, at least, a performance-based classification scheme is not available. Especially, the influence of the quality of the 'raw' material (wooden boards) on the load carrying capacity of CLT elements is hardly investigated yet. For this reason, within this work, bending tests on 24 CLT plates consisting of wooden boards from three different strength classes have been carried out. The global mechanical response as well as the formation of failure mechanisms were investigated, including a full-field deformation measurement system, which allowed for a qualitatively as well as quantitatively identification of board failure modes. Interestingly, no influence of the board strength class on the elastic limit load of the CLT plates was observed, but the situation was different for the load displacement history beyond the elastic regime, where basically, two different global failure mechanisms could be distinguished. The obtained knowledge about the 'post-elastic' behaviour of CLT plates may serve as a basis for the optimisation of CLT products and the development or improvement of design concepts, respectively. Moreover, the obtained large 'post-elastic' capacity reserve of CLT consisting of high quality boards could lead to a better utilisation of the raw material.

Closed-form solutions for predicting the thick elastic plate behavior of CLT and timber panels with gaps

“…When dealing with the out-of-plane behavior of CLT and innovative timber panels, the governing failure modes are longitudinal tensile failures of bottom layer and rolling shear failure of cross layer. This was observed during many experimental investigation of the literature [25,26,4,27,13]. In the previous study by the authors [1], the tensile and rolling shear stresses at failure point of tested timber floors with wide gaps in 4-points bending have been predicted with the FE homogenization and were in agreement with mean strength values from the literature.…”

A numerical upper bound formulation with sensibly-arranged velocity discontinuities and orthotropic material strength behaviour

“…This may represent an important finding for future developments, which could lead to a general algorithm for an adaptive introduction and re-arrangement of velocity discontinuities, as an efficient alternative to existing adaptive mesh refinement strategies. Especially for laminated structures and orthotropic materials, where plastic failure often occurs in a very localised mechanism, as shown for wood at the microscale in (Lukacevic et al, 2014;Lukacevic and Füssl, 2016) and at the product scale in (Hochreiner et al, 2013(Hochreiner et al, , 2014, such an approach could have great value. Moreover, the efficiency of numerical limit analysis in combination with the accuracy of the extended finite element formulations presented in (Lukacevic et al, 2014;Lukacevic and Füssl, 2016) could lead to more flexible engineering design tools, in which the focus can be switched between accuracy and efficiency as needed.…”

19.05: CLT‐steel composite slimfloor construction: An investigation of mechanical behaviour using finite element software

“…In addition to replicating the mechanical behaviour observed by Bosl, the new material model and modelling approach was applied to a test setup used by Hochreiner et al [20]. In this work, a square panel of CLT, fixed on four sides was subjected to a central patch loading.…”