Nationwide, bridges are deteriorating at a rate faster than they can be rehabilitated and maintained. This has resulted in a search for new methods to rehabilitate, repair, manage, and construct bridges. As a result, structural health monitoring and smart structure concepts have emerged to help improve bridge management. In the case of timber bridges, however, a limited amount of research as been conducted on long-term structural health monitoring solutions, and this is especially true in regards to historic covered timber bridges. To date, evaluation efforts of timber bridges have focused primarily on visual inspection data to determine the structural integrity of timber structures. To fill this research need and help improve timber bridge inspection and management strategies, a 5-year research plan to develop a smart timber bridge structure was undertaken. The overall goal of the 5-year plan was to develop a turnkey system to analyze, monitor, and report on the performance and condition of timber bridges. This report outlines one phase of the 5-year research plan and focuses on developing and attaching moisture sensors onto timber bridge components. The goal was to investigate the potential for sensor technologies to reliably monitor the in situ moisture content of the timber members in historic covered bridges, especially those recently rehabilitated with glulam materials. The timber-specific moisture sensors detailed in this report and the data collected from them will assist in advancing the smart timber bridge.
This project identifies drivers for, and barriers to, the increased use of prefabricated timber building (PTB) systems in Class 2 to 9 commercial buildings, such as apartments, hotels, office buildings and schools.
PTB systems in Australia are in a formative stage and yet to achieve broad acceptance in the marketplace as a conventional method of building.
Opportunities for PTB systems can use timber’s well-established benefits such as high strength-to-weight ratio; design and construction flexibility; general environmental credentials including carbon sequestration; and prefabrication’s suitability for use on brown-field, restricted access and difficult sites and developments. In addition legislative constraints have now been largely removed (e.g. through changes to the 2016 National Construction Code).
An increase in large scale mid-rise prefabricated buildings, and with the increasing nationalisation and internationalisation of the top tier building companies, suggests market acceptance will grow as PTB buildings are seen as ‘normal’.
The Task Group on Combustible Construction is in the process of evaluating a proposed code change request related to buildings of encapsulated mass timber construction (EMTC). As part of the analysis of the code change request, an impact analysis is required that includes a cost-benefit analysis.
Hanscomb was hired to provide a cost-benefit analysis and to compare the estimated value of the following:
1. The cost of constructing a building of mass timber (unprotected) versus a building constructed of encapsulated mass timber (e.g. mass timber protected with a double layer of Type X gypsum board) versus a traditional concrete and steel building.
2. The time to build a building of mass timber construction (unprotected) versus a building of encapsulated mass timber construction versus a traditional concrete and steel building.
3. The annual maintenance costs of building of mass timber construction versus a building of encapsulated mass timber construction versus a traditional concrete and steel building.
For the purposes of this study two sets of conceptual floor plans and elevations have been created:
1. A 12 storey building with a Group C major occupancy (residential) where each storey is 6,000 m2 in floor area.
2. A 12 storey building with a Group D major occupancy (office) where each storey is 7,200 m2 in floor area.
This report 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. Three- and four-storey schools and larger floor areas in wood construction require an Alternative Solution.
The report identifies key fire safety features offered by combustible construction materials including tested and currently widely available engineered mass timber products, such as glued-laminated timber and cross-laminated timber. A risk analysis identifies the risk areas defined by the objectives of the British Columbia Building Code (BCBC 2018) and evaluates the level of performance of the Building Code solutions for assembly occupancies vis-à-vis the level of performance offered by the proposed schools up to four storeys in building 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 report is closely related to the study Design Options for Three-and Four-Storey Wood School Buildings in British Columbia, which illustrates the range of possible timber construction approaches for school buildings that are up to four storeys in height.