The intention of this STAR is a more detailed summary of the relevant work, done during the last 20 years on the topic of CLT. Additional references not included in the documents of SC5.T1 were added highlighting also CLT relevant publications not directly addressing content of the CLT draft version for EC 5. Apart from providing additional references for all topics and chapters of SC5.T1 draft documents edited by WG 2 / TG 1 & TG 3 within this STAR, further necessary scoentific work was identified and listed.
Determining the mechanical properties of cross-laminated timber (CLT) panels is an important issue. A property that is particularly important for CLT used as shear walls in buildings is the in-plane shear modulus. In this study, a method to determine the in-plane shear modulus of 3- and 5-layer CLT panels was developed based on picture frame tests and a correction factor evaluated from finite element simulations. The picture frame test is a biaxial test where a panel is simultaneously compressed and tensioned. Two different testing methods are simulated by finite elements: theoretical pure shear models as a reference cases and picture frame models to simulate the picture frame test setup. An equation for calculating the shear modulus from the measured shear stiffnesses in the picture frame tests is developed by comparisons between tests and finite element simulations of the CLT panels. The results show that pure shear conditions are achieved in the central region of the panels. No influence from the size of the tested panels is observed in the finite element simulations.
In high timber structures, cross-laminated timber panels are common structural elements. The wall and floor panels are typically connected with steel plates, angle brackets, hold-downs, and screws. Based on analytical research, it seems that panel-to-panel connections give additional stiffness due to structural redundancies resulting from...
The scope of this study is to evaluate the existing test methods for deciding the in-plane shear strength and stiffness of cross laminated timber (CLT) panels, and suggest a new test method. The evaluation of the existing methods point out that none of the methods isolate the pure membrane shear stress. This means that the results have to be interpreted and modified analytically in the process to define the in-plane shear properties. A new Direct shear test method is suggested to apply pure membrane shear force on the test specimen. In the suggested method the force is applied to a hinged steel frame, which is continuously bonded to the edges of the CLT panel. As the steel frame and the panel are deformed as parallelograms, the applied force are translated to pure membrane shear in the tested panel.