Classifications of volatile products that may pose health and comfort risks to occupants tend to be restricted by current regulations. It seems important to sample air from concrete, wood and steel buildings to measure the compounds present. Ideally, measurements at different time intervals could be considered to qualify and quantify contaminant dispersion dynamics over time. The project aims to identify a possible advantage of wood construction in the face of air quality, to identify the main contaminants (quantity and toxicity) and to propose sampling and measurement techniques adapted to the building environment.
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 Although an increasing amount of mass timber high-rises are being built all around the world, lack of information and outdated preconceptions are some of the obstacles that are keeping mass timber products from increasing their market share in high-rise construction.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.
Prefabrication of timber envelope components is a constantly developing research field, which attracts interest from various sectors of expertise thanks to the conspicuous advantages it can confer in terms of resources savings, as well as quality management and safety for all actors involved in the process. The present paper goes through the design of a newly conceived external wall system for tall CLT buildings, entirely preassembled off-site and so able to be installed on his final position via crane, renouncing to scaffolds for the façade completion. This not only allows for the construction phase to speed up but also for immediate protection of loadbearing timber elements from weather agents exposure. The work follows three main phases: the functional analysis and layer definition, component design through bi-dimensional study of joint operating mechanism and tri-dimensional validation of the system. Main author findings outline how success of prefabricated systems and their durability over service life is strongly dependent on the effectiveness of joint design.
The report includes an overview of different floor assemblies used all over Europe. They have been selected and evaluated carefully and from that the floor assemblies are divided into different groups in order to fit to limit the number of possible setups. Hence the grouping is made in a manner that will facilitate modelling of floor assemblies using the different methods as developed within this project, Silent Timber Build. It can also be used in order to recommend different floor assemblies for different buildings and usage. The software that has been used and further developed within this project is a French software adapted to wooden building floor and wall components, “SEA Wood". In addition FEM software is used in order to improve and verify the results particularly in the low frequencies, which is of particular interest for structural solutions in wood.
To evaluate the building envelope performance of the generic exterior wall assemblies developed for use in mid-rise wood buildings, hygrothermal properties of materials used in the assemblies are needed as input data for hygrothermal modelling. Hygrothermal properties were developed for fire retardant treated plywood, regular gypsum sheathing, spray polyurethane foam and cross-laminated timber. This report documents results of the hygrothermal property determinations.
The objective of this part of the research project was to generate a set of reliable and
representative data on hygrothermal properties of a number of selected building materials as
1. D-Blaze Treated Plywood
2. Dricon Treated Plywood
3. Gypsum Sheathing
4. Closed Cell Spray Polyurethane Foam Insulation (Purple in Colour)
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.
This paper presents the numerical-experimental analysis of an innovative connector for CLT structures. The connection system, named X-RAD, has generated a new approach to CLT constructions, characterized by precision and effectiveness. Thanks to the possibility of assembling the X-RAD connectors directly within the factory, the CLT panels can be lifted during the production phases, transported to the construction site and assembled by the use of a sole element represented by the steel elements placed at the corners of the different panels. The X-RAD components in fact are meant to be pre-assembled in the factory by using all-threaded self-tapping screws, so that the system could act as a lifting point for the positioning operations. Several experimental tests are presented and analysed: tests on screws and monotonic tests on different load configurations. The test outcome lead to the mechanical characterization of the connector. X-RAD has been studied also with an analytical approach: the different load configurations have been solved “at limit” condition by the use of equilibrium. The experimental and analytical approach permitted to define respectively the experimental and the analytical capacity domains. Finally a method to verify X-RAD loaded by a generic external load is proposed.
The behaviour of multi-storey buildings braced with Cross-Laminated-Timber (CLT) cores and additional shear walls is examined based on numerical analyses of various 3-dimensional configurations. Two ways of calibrating numerical model are proposed according to codes and experimental test data respectively, including calibration of parameters that characterise connections between CLT panels in building cores and shear walls. Results of analyses of entire buildings are presented in terms of principal elastic periods, and base shear and up-lift forces. Discussion addresses primary issues associated with behaviour of such systems and modelling them.
New research is showing that wood buildings are more likely to harbor environmental microbes with beneficial health effects. This pilot project will study various surface materials in both the lab setting and occupied mass timber buildings to assess effects on occupants’ health and comfort as well as indoor air quality.