This paper investigates the seismic analysis of multi-story cross laminated timber (XLAM) buildings. The influence of different parameters such as wall geometry, vertical load level, friction and, most importantly, connection stiffness, strength and ductility is assessed. Linear and nonlinear finite element (FE) analyses are carried out on a hypothetic four-story case study building. The XLAM building behaviour factors are derived for different cases using a simplified method. Values in the range of 2 to 3 have been obtained depending on whether monolithic or segmental walls are used. Further nonlinear dynamic analyses carried out on a part of the case study building show that friction may have a beneficial effect on the seismic resistance of XLAM buildings. However it is advised that its influence is conservatively neglected until further investigations are performed. Obtained results provide an important insight for both academics and practicing engineers into the FE modelling and design of XLAM buildings using different code-based approaches. This data is also crucial for the preparation of new seismic design codes on XLAM timber buildings.
This paper presents the results of an experimental study whose objective was to investigate the behavior of a hybrid wood shear-wall system defined herein as a combination of traditional light-frame wood shear walls with post-tensioned rocking Cross-Laminated Timber (CLT) panels. The post-tensioned CLT panels in the hybrid system offer both vertical and lateral load resistance and self-centering capacities. The traditional Light-Frame Wood Systems (LiFS) provide additional lateral load resistance along with a large amount of energy dissipation through the friction of nail connections. Thus, a combination of these two types of structures, in which traditional light-frame wood shearwalls are utilized as structural partition walls, may provide an excellent structural solution for mid-rise to tall wood buildings for apartments/condos, where there is a need for resisting large lateral and vertical loads as well as structural stability. In this study, a real-time hybrid testing algorithm using a combination of time-delay updating and Newmark-Beta feed forward to reduce the undesirable effects of time delay was introduced. The top two-stories of a three-story building were modeled as a numerical substructure with the first story as the experimental CLT-LiFS substructure. The experimental results of the hybrid wall are presented and discussed in this paper.
Joints and shear walls of buildings made from dowel-laminated timber were experimentally investigated and assessed. Based on cyclic tests on shear walls, a nonlinear dynamic building model was developed. The developed model served to evaluate the seismic behaviour of buildings made from dowel-laminated timber and to derive a preliminary behaviour factor q required for seismic design of this building typology.
An advanced modelling tool, WoodST, has been developed for fire safety analysis of timber structures. It is demonstrated that this advanced modelling tool can predict the structural response of LVL beams, glulam bolted connections, OSB-web I-joist and wood-frame floors under forces and fire conditions with an accuracy acceptable to design practitioners (i.e., within 10% of test data). The developed modelling tool can:
Fill the gap in terms of suitable models for timber connections, which is an impediment for the design and construction of tall wood buildings;
Provide a cost-effective simulation solution compared to costly experimental solutions; and
Significantly reduce the cost and shorten the time for the development and/or optimization of new wood-based products and connections.
Project contact is Sylvain Ménard at Université du Québec à Chicoutimi
Assemblies with glued-in rods allow architectural freedom. They are in fact invisible since they are found in the mass of the structural element. Some work has begun to document this type of assembly by considering static tests in single-sided traction and single-sided creep tests (Verdet, 2016). In order to continue this effort to specify the limits of this type of assembly, it is proposed to consider the lateral forces for assemblies with single and multiple rod connections. This project will therefore aim to document the ability of these assemblies to carry lateral loads.
Project contact is Christian Dagenais at Université Laval
The National Building Code of Canada (NBCC, NRC 2015) proposes equations to limit acceleration at the top of a tall building. These equations were developed and validated on several buildings designed between 1975 and 2000. The buildings built during these years are made of concrete or steel. It is therefore not certain that the NBCC equations can be applied for tall wooden buildings; wood being a lighter material than concrete and steel. In this project, the PhD candidate will study the impact of lateral load resistance systems and fastening systems used in timber framing on natural frequency and damping as well as its response due to wind loads. The influence of non-structural elements will also be studied. Two high-rise wooden buildings (Origine, 13 floors in Quebec City and Arbora, 8 floors in Montreal) are currently being instrumented to obtain information on the dynamic behavior of the structure. The measurements taken on these two buildings will be used, among other things, to validate theoretical models developed in the context of the doctorate.
The work presented in this report is a continuation of the FPInnovations' research project on determining the performance of the CLT as a structural system under lateral loads. A two storey full-scale model of a CLT house was tested under quasi-static monotonic and cyclic lateral loading in two directions, one direction at a time. In total five tests were performed; one push-over and two cyclic tests were conducted in the longer symmetrical direction (E-W), and two cyclic tests were performed in the shorter asymmetrical direction (N-S). In addition, before and after each test, natural frequencies of the house in both directions were measured. The main objective of the tests was to investigate 3-D system behaviour of the CLT structure subjected to lateral loads. The CLT structure subjected to lateral loads performed according to the design objectives.