This research is about the design process, development and fabrication of a free-form structure in crosslaminated timber (CLT) panels. Since sustainability, ecology and structural design are now relevant in any building project, the purpose of this research is to demonstrate that CLT panels can be used as an ecoresponsive strategy based on a building form. This paper presents the use of a tessellation construction system for designing and producing a freeform surface in CLT for a specific regional and industrial context. The research/creation process and the retroactive simulation generated by the parametric modelling software enabled the development of a singular architectural project where the structural aspect and the manufacturing are the inherent part of the integrated design process. Finally, the cutting files can be generated automatically for an easy transfer to CNC machine tools.
The latest developments in seismic design philosophy have been geared towards developing of so called "resilient" or "low damage" innovative structural systems that can reduce damage to the structure while offering the same or higher levels of safety to occupants. One such innovative structural system is the Pres-Lam system that is a wood-hybrid system that utilizes post-tensioned (PT) mass timber components in both rigid-frame and wall-based buildings along with various types of energy disspators. To help implement the Pres-Lam system in Canada and the US, information about the system performance made with North American engineered wood products is needed. That information can later be used to develop design guidelines for the designers for wider acceptance of the system by the design community.Several components influence the performance of the Pres-Lam systems: the load-deformation properties of the engineered wood products under compression, load-deformation and energy dissipation properties of the dissipators used, placement of the dissipators in the system, and the level of post-tensioning force. The influence of all these components on the performance of Pres-Lam wall systems under gravity and lateral loads was investigated in this research project. The research project consisted of two main parts: material tests and system tests.
At present in Chile it is not possible to construct buildings higher than 3 storeys using timber as structural material. This difficulty is due to high demands of regulations, in addition to cultural reasons, even though there are buildings in timber with more than 5 storeys built in 1910 in Chile (Sewell), which are preserved nowadays. A multidisciplinary team at UC Timber Innovation Center (CIM UC) works on the design of a mid-rise building in timber with a platform frame system for a mining company with few budget restrictions for this specific project. The results will be presented in this paper. Been the economic feasibility the main concern of the UC Timber Innovation Center (CIM UC), in order to spread this technology to a standard client, a larger team is working in parallel towards a proposal of modification of structural design regulations for the construction of mid-rise buildings in Chile with timber platform frame system. The work included an extensive bibliographic revision, followed by structural tests on 2D and 3D timber structures.
Cross-laminated timber (CLT) is a relatively new type of massive timber system that has shown to possess excellent mechanical properties and structural behavior in building construction. When post-tensioned with high-strength tendons, CLT panels perform well under cyclic loadings because of two key characteristics: their rocking behavior and self-centering capacity. Although post-tensioned rocking CLT panels can carry heavy gravity loads, resist lateral loads, and self-center after a seismic event, they are heavy and form a pinched hysteresis, thereby limiting energy dissipation. Conversely, conventional light-frame wood shear walls (LiFS) provide a large amount of energy dissipation from fastener slip and, as their name implies, are lightweight, thereby reducing inertial forces during earthquakes. The combination of these different lateral behaviors can help improve the performance of buildings during strong ground shaking, but issues of deformation compatibility exist. This study presents the results of a numerical study to examine the behavior of post-tensioned CLT walls under cyclic loadings. A well-known 10-parameter model was applied to simulate the performance of a CLT-LiFS hybrid system. The posttensioned CLT wall model was designed on the basis of a modified monolithic beam analogy that was originally developed for precast concrete-jointed ductile connections. Several tests on post-tensioned CLT panels and hybrid walls were implemented at the Large Scale Structural Lab at the University of Alabama to validate the numerical model, and the results showed very good agreement with the numerical model. Finally, incremental dynamic analysis on system level models was compared with conventional light-frame wood system models.
Installing between-joist bracing can be an economical and effective means of mitigating excessive vibration levels in wood floors associated to human discomfort. Effectiveness of between-joist bracing depends upon its own rigidity that accounts for the location of bracing, geometric arrangement and connection stiffness of installed...
Project contact is Y.H. Chui at the University of Alberta
Wood shear wall systems with insulated sheathing are commonly implemented to meet a higher standard of building energy efficiency. Adding a layer of continuous thermal insulation exterior to the cavity insulation, insulated sheathing, to reduce thermal bridging is getting more popular in practice. The impact of the intermediated insulation on racking performance of shear walls has recently been investigated by experimental studies. The test data provides better understanding on the influence of various construction configurations. Nevertheless, there is a need to provide an alternative approach which enables engineers to calculate the design capacities of shear walls with insulated sheathing. In this project, the available analytical models and approaches for determining shear resistances of shear walls are reviewed and compared. A new modified analytical model will be developed based on comparisons and the test results.