Cross-laminated timber, also known as X-Lam or CLT, is well established in
Europe as a construction material. Recently, implementation of X-Lam products and
systems has begun in countries such as Canada, United States, Australia and New
Zealand. So far, no relevant design codes for X-Lam construction were published in
Europe, therefore an extensive research on the field of cross-laminated timber is being
performed by research groups in Europe and overseas. Experimental test results are
required for development of design methods and for verification of design models
accuracy.
This thesis is part of a large research project on the development of a software
for the modelling of CLT structures, including analysis, calculation, design and
verification of connections and panels. It was born as collaboration between Padua
University and Barcelona"s CIMNE (International Centre for Numerical Methods in
Engineering). The research project started with the thesis “Una procedura numerica per
il progetto di edifici in Xlam” by Massimiliano Zecchetto, which develops a software,
using MATLAB interface, only for 2D linear elastic analysis. Follows the phase started
in March 2015, consisting in extending the 2D software to a 3D one, with the severity
caused by modelling in three dimensions. This phase is developed as a common project
and described in this thesis and in “Pre-process for numerical analysis of Cross
Laminated Timber Structures” by Alessandra Ferrandino.
The final aim of the software is to enable the modelling of an X-Lam structure in
the most efficient and reliable way, taking into account its peculiarities. Modelling of
CLT buildings lies into properly model the connections between panels. Through the
connections modelling, the final aim is to enable the check of preliminarily designed
connections or to find them iteratively, starting from hypothetical or random
connections.
This common project develops the pre-process and analysis phases of the 3D
software that allows the automatic modelling of connections between X-Lam panels. To achieve the goal, a new problem type for GiD interface and a new application for
KRATOS framework have been performed. The problem type enables the user to model
a CLT structure, starting from the creation of the geometry and the assignation of
numeric entities (beam, shell, etc.) to geometric ones, having defined the material, and
assigning loads and boundary conditions. The user does not need to create manually the
connections, as conversely needs for all commercial FEM software currently available;
he just set the connection properties to the different sides of the panels. The creation of
the connections is made automatically, keeping into account different typologies of
connections and assembling of Cross-Lam panels. The problem type is special for XLam structures, meaning that all features are intentionally studied for this kind of
structures and the software architecture is planned for future developments of the postprocess phase.
It can be concluded that sound bases for the pre-process and analysis phases of
the software have been laid. However, future research is required to develop the postprocess and verification phases of the research project.
Results from a series of blast tests performed in October 2016 on three two-story, single-bay cross-laminated timber (CLT) structures demonstrated the ability of CLT construction to resist airblast loads in a predictable fashion. These tests were performed on structures without superimposed load to limit inertial resistance. Subsequently, a follow-on series of tests...
Comparison of Bending Stiffness of Cross-Laminated Solid Timber Derived by Modal Analysis of Full Panels and by Bending Tests of Strip-Shaped Specimens
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