The paper presents the design and modelling of Cathedral Hill 2, a 15-storey timber building, planned for construction in Canada. The building is a 59-metre tall office-use construction with an all-timber structure where the lateral-load-resisting system consists of segmented Pres-Lam walls...
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.
This research focuses on the dynamic behaviour of long span LCC flooring systems. Experimental testing and finite element modelling was used to determine the dynamic behaviour, with particular regard to the natural frequency, fn and mode shape of an LCC floor.
Both the experimental results and the finite element analyses agreed and showed that increased stiffness increased the natural frequency of the floor, and the boundary conditions influenced the dynamic behaviour of the LCC floor. Providing more restraint increased the stiffness of the floor system. The connectors' stiffness did not influence the dynamic performance of the floor.
The research showed that a 8 m LCC long span floor can be constructed using LVL joists of between 300 mm to 400 mm depth with a concrete thickness of 65 mm for the longer spans, and joists of between 150 mm to 240 mm depth in conjunction with a concrete topping thickness of 100 mm for the shorter spans.
The low carbon footprint and high structural efficiency of engineered wood materials make tall-timber buildings an attractive option for high-rise construction. However, due to the relatively low mass and stiffness characteristics of timber structures, some concerns have been raised regarding their dynamic response. This paper examines the dynamic behaviour of tall timber buildings under tornado and downburst wind loads. It summarizes the results of extensive response history analyses over a suite of FE structural models subjected to different wind actions and compares them with the ISO10137 comfort criteria. In general, large levels of floor accelerations are observed in particular for stiffer medium-rise structures with significant density of walls. It is shown that downburst loading governs the peak acceleration response of medium-rise buildings whilst tornado loading becomes more critical for taller buildings. The effectiveness of TMDs in reducing peak acceleration values is explored. This study emphasizes the need for further studies on the dynamic behaviour of tall timber buildings.
Pres-Lam timber structures are being adopted throughout New Zealand and around the world. This innovative method of timber construction combines the use of large engineered timber members with posttensioning cables/bars. The hybrid version of the Pres-Lam system improves seismic performance through the...
The following paper describes the numerical modelling used to predict the dynamic behaviour of a posttensioned timber building with the addition of a hysteretic energy dissipation system. This modelling is in support of a shaking table test programme performed on a 2/3rd scale, 3-dimensional, 3-storey structure made from post-tensioned timber frames in both directions. Testing was carried out in the structural laboratory of the University of Basilicata in Potenza, Italy as part of a collaborative project between the University and the University of Canterbury in Christchurch, New Zealand. Modelling used two non-linear finite element codes, SAP2000 and RUAUMOKO. This paper compares numerical results obtained from the model with and without additional dissipative elements in order to better understand the dynamic behaviour of post-tensioned timber structures. Comparison is made with the results of the experimental campaign and amongst the finite element programs themselves.
Timber buildings are characterized by a thermal inertia lower than other technological solutions in construction. For this reason, some configurations may lead to higher cooling demand and poorer energy performance in hot climates, such as the Mediterranean ones. Possible improvement interventions often regard additional thermal mass...