Project contact is Jianhui Zhou at the University of Northern British Columbia
Building acoustics has been identified as one of the key subjects for the success of mass timber in the multi-storey building markets. The project will investigate the acoustical performance of mass timber panels produced in British Columbia. The apparent sound transmission class (ASTC) and impact insulation class (AIIC) of bare mass timber elements as wall and/ or floor elements will be measured through a lab mock-up. It is expected that a database of the sound insulation performance of British Columbia mass timber products will be developed with guidance on optimal acoustical treatments to achieve different levels of performance.
This Report presents the results from experimental studies of the airborne sound transmission of mass timber assemblies, together with an explanation of the calculation procedures to predict the apparent sound transmission class (ASTC) rating between adjacent spaces in a building constructed of mass timber assemblies.
The experimental data which is the foundation for this Report includes the laboratory measured sound transmission loss of wall and floor assemblies constructed of Cross Laminated Timber (CLT), Nail-Laminated Timber (NLT) and Dowel-Laminated Timber (DLT), and the laboratory measured vibration reduction index between assemblies of junctions between CLT assemblies. The presentation of the measured data is combined with the presentation of the appropriate calculation procedures to determine the ASTC rating in buildings comprised of such assemblies along with numerous worked examples.
Several types of CLT constructions are commercially available in Canada, but this study focused on CLT assemblies with an adhesive applied between the faces of the timber elements in adjacent layers, but no adhesive bonding between the adjacent timber elements within a given layer. These CLT assemblies could be called “Face-Laminated CLT Assemblies” but are simply referred to as CLT assemblies in this Report. Another form of CLT assemblies does have adhesive applied between the faces of the timber elements in adjacent layers as well as adhesive to bond the adjacent timber elements within a given layer. These assemblies are referred to as “Fully-Bonded CLT Assemblies” in this Report. Because fully-bonded CLT assemblies have different properties than face-laminated CLT assemblies, the sound transmission data and predictions in this Report do not apply to fully-bonded CLT assemblies.
This study illustrates the range of possible wood construction approaches for school buildings that are up to four storeys in height. As land values continue to rise, particularly in higher-density urban environments, schools with smaller footprints will become increasingly more necessary to satisfy enrollment demands. There are currently a number of planned new school projects throughout British Columbia that anticipate requiring either three-or four-storey buildings, and it is forecasted that the demand for school buildings of this size will continue to rise.
This study is closely related to the report Risk Analysis and Alternative Solution for Three- and Four-Storey Schools of Mass Timber and/or Wood-Frame Construction prepared by GHL Consultants, which explores the building code related considerations of wood construction for school buildings that are up to four storeys in height. Though wood construction offers a viable structural material option for these buildings, the British Columbia Building Code (BCBC 2018) currently limits schools comprised of wood construction to a maximum of two storeys, while also imposing limits on the overall floor area. As such, the reader is referred to the GHL report for further information regarding building code compliance (with a particular emphasis on fire protection) for wood school buildings.
The purpose of this guide is to provide an introduction to the concept of encapsulated mass timber construction. This guide provides an overview of encapsulation techniques for mass timber construction, and other related fire protection measures, and summarizes some approved encapsulation materials and application methods and identifies additional requirements for safety during construction. This guide is intended to help architects, engineers and designers by reducing uncertainty and allowing for more confidence in design, as well as providing authorities having jurisdiction and inspectors with a reference for simple design review.
The purpose of the study is to evaluate and summarize any technical or other impediments to using hem-fir in mass timber products. The different mass timber products included in the study are cross-laminated timber (CLT), glue-laminated timber (glulam), dowel-laminated timber (DLT) and nail-laminated timber (NLT).
Mass timber is a family of Solid Laminate Timber Systems (SLTS) formed from smaller sections of timber connected by glue, mechanical fixings, moisture movement or a combination of methods. These products, which include Structural Composite Lumber, GluLam, Cross Lam, Nail Lam and Dowel Lam (or Brettstapel), have over the past two decades seen an extraordinary upsurge in use internationally. This global phenomenon has been driven by a greater emphasis on the sustainable use of renewable resources and by significant technological developments in the manufacture of SLTS. This research paper considers the merits of each of these products, their manufacturing processes and the corresponding quality assurance requirements necessary for successful project delivery. The paper describes the advantages and barriers to the use of the mass timber and provides an overview of the various aspects to be considered during design for offsite and modular construction. The work presented also provides case studies of how these products have been researched and utilised into live projects in the UK utilising local resource resulting in the formation of new supply chain arrangements. The work further explains the advantages of the respective systems for the given application including information on species selection, connection systems employed and the necessary onsite and offsite management approaches deployed.
Project contact is Shiling Pei at the Colorado School of Mines
NHERI Tallwood project is an effort to develop and validate a resilient-based seismic design methodology for tall wood buildings. The project started in September 2016 and will last till 2020. The project team will validate the design methodology through shake table testing of a 10-story full-scaled wood building specimen at NHERI@UCSD. It will be the world's largest wood building tested at full-scale.