The innovation in tall mass-timber buildings is illustrated by the Brock Commons student residence at the University of British Columbia also known as the UBC Tall Wood Building. It is amongst the world’s tallest timber hybrid building with 18 stories and 53 meters’ height. The building has 17 stories of mass-timber superstructure resting on a concrete podium with two concrete cores that act as a lateral force resisting system for earthquake and wind forces. Construction of the mass-timber superstructure took ten weeks whereas the concrete cores were built in fourteen weeks. There could have been a substantial reduction in the project timeline leading to cost savings, as well as a further reduction of environmental footprint if mass-timber had been used for the cores. The objective of this work was to evaluate the possibility to design the UBC Tall Wood Building using mass-timber cores. A validated numerical model was used to study the feasibility of replacing the concrete cores by cores made of Cross Laminated Timber (CLT). The results presented herein show that, with adjustments in the configuration, the structure can meet the seismic performance criteria as per the Canadian code with CLT cores.
The use of mass timber in high rise construction is an innovation. Mass timber construction has influential benefits including a lower overall construction time, a lower environmental impact, the use of renewable resource and an improved aesthetics. Despite the mentioned benefits, mass timber is not the traditional material for low to mid-rise commercial, institutional and residential construction in Canada. This is partially due to the need to explore the efficiency of mass timber construction relative to traditional construction. Detailed quantitative documentation of successful construction projects assists organisations planning mass timber high-rise projects by understanding and quantifying the advantages to ensure the viability of the construction process. This research project aims to understand the performance of mass-timber construction in the context of a construction manager, particularly the time saved due to completion of structural and envelope systems early. The case study chosen for this thesis is the tallest mass timber hybrid building in the world: Tallwood House. The research team studied the project in a macro-level perspective to investigate the building elements as single entities. Moreover, a micro-level study focuses on the performance of every level of the following elements: mass timber structure, envelope cladding systems and cross-laminated timber drywall encapsulation. The macro-level study investigates: (1) The production rate of the various building elements, (2) The coordination between structural trades to build a heavily pre-fabricated building using a single crane, and (3) The labor efforts per discipline. Moreover, the micro-level study investigates: (4) The variability of productivity of all levels, (5) A statistical investigation of three factors on cross-laminated timber installation, (6) Schedule reliability of preliminary planned schedule relative to the construction schedule (actual progress), (7) Earned value analysis, and (8) Planned percent complete to study the reliability of weekly work plans relative to construction schedules. All metrics were validated by the senior project manager through a discussion and confirmation of the inputs, findings and conclusions drawn. The claimed contribution of this research is an advanced state of knowledge about mass timber by exploring the efficiency of the construction process.
The University of British Columbia has an interest in incorporating life cycle environmental impacts and financial information into project planning, as well as research and teaching. As part of a tall wood building research program with the UBC Sustainability Initiative and Dept. of Civil Engineering, a comprehensive life cycle assessment (LCA) and life cycle costing (LCC) study was done of two student high-rise residential buildings, based on the result of whole building LCA done by Athena Sustainable Materials Institute and whole building LCC done by Sensible Building Science. These buildings are of similar design but Brock Commons Tallwood House has a hybrid mass-timber structure and Ponderosa Commons Cedar House has a more traditional concrete structure. This paper will include a brief overview of the research process, data collection, analysis, and key results. The paper will then focus on the main opportunities, challenges, and lessons learned from both the results of the LCA/LCC projects and the process of conducting the study.
Wood has seen a resurgence recently as a construction material driven by technological advances and a growing concern for the environment. Although an increasing amount of mass timber high-rises are being built all around the world, lack of information and outdated preconceptions are some of the obstacles that are keeping mass timber products from increasing their market share in high-rise construction. Academia and industry leaders must keep track of the progress that is being made and inform the general public as innovation and technological advances continue to take place. In this context, the University of British Columbia has recently completed the construction of the Brock Commons Tallwood House. This 18-story residence building employs two reinforced concrete cores and a mass timber structure composed of cross laminated timber panels, glued-laminated columns, and parallel strand lumber columns. With this, the building is currently the tallest wood building in the world and a testament to the suitability of engineered wood elements for high-rise construction. Aiming to address the lack of information surrounding mass timber high rise construction, this thesis documents the quality assurance (QA) and quality control (QC) practices that were put in place during the delivery of the building. The main objective of this research was to identify and present lessons learned from the application of these QA/QC practices. To do this, various QA/QC practices were identified and analyzed by reviewing the project specifications and other project documents, reviewing recognized industry standards, and interviewing various members of the project team. This study found a series of comprehensive and well-planned QA/QC practices that were put in place by the project team and that were appropriate to comply with the project requirements. This study concluded that most of these practices are replicable and advisable for future projects. The different QA/QC practices that were identified and the lessons learned from their application are presented in this thesis.
This paper presents an experimental investigation of the structural behaviour and dynamic characteristics of an innovative, double-span, point-supported Cross Laminated Timber (CLT) floor system for an 18-stroey woodhybrid student residence building at the University of British Columbia Campus in Vancouver, Canada. Eighteen CLT floor specimens with or without service openings were fabricated by three manufacturers and tested. The fundamental natural frequency, stiffness and deformability, load-carrying capacity, two-way action, compression perpendicular to grain at the supports, and the failure mechanism of the floor systems were investigated. In addition, the effect of openings in the floors was investigated along with the manufacturer-related properties of the CLT floors were examined. The tests gave an insight into the structural behaviour of this innovative floor system, provided test data that was used for calibration of the Finite Element Models of the building, and helped choose the right product for the floors.
In this paper, we discuss the structural design of one of the tallest timber-based hybrid buildings in the world: the 18 storey, 53 meter tall student residence on the campus of the University of British Columbia in Vancouver. The building is of hybrid construction: 17 storeys of mass wood construction on top of one storey of concrete construction. Two concrete cores containing vertical circulation provide the required lateral resistance. The timber system is comprised of cross-laminated timber panels, which are point supported on glued-laminated timber columns and steel connections between levels. In addition to providing more than 400 beds for students, the building will serve as an academic site to monitor and study its structural performance, specifically horizontal building vibration and vertical shrinkage considerations. We present the challenges relating to the approval process of the building and discuss building code compliance issues.