A team of Australian researchers has been working to measure the onsite installation productivity of Cross Laminated Timber (CLT) in multi-storey building projects, demonstrating the significant productivity opportunities associated with the material’s use, and how to maximise them.
Professor Perry Forsythe, of the University of Technology Sydney’s School of the Built Environment, who led the research, sought to demonstrate the potential of timber in terms of the productivity gains it offers, given that multi-storey CLT buildings are relatively new to Australia.
Professor Forsythe said productivity is important to anyone responsible for planning, supervising, estimating and procuring construction work.
“Prefabrication, in its general terms, is seen as a way forward for improving the productivity and efficiency of construction onsite. This is also applicable to CLT construction, which is widely regarded in terms of panelised prefabrication,” Professor Forsythe said.
“Unfortunately, progress in making this a common reality in Australia has been slow, particularly because of a lack of understanding and knowledge about the potential advantages it offers, including reduced construction time and simplified processes.
“Quantitative evidence to support these advantages is still relatively scarce. Our hope is the intelligence gathered through this project can help change that.”
The team chose to focus its research around an in-depth case study relating to a specific medium, mid-rise timber construction project. Time-lapse photography was used to gather site assembly information, with the resulting footage converted into quantitative data, including the number of worker and crane hours required to install wall and floor panels.
Statistical analysis was then used to derive productivity rates, floor cycle times and other findings relating to the installation of CLT.
“The research showed us clearly that a high rate of productivity – or a large number of square meters per hour – is possible, if the project manager plans carefully for an efficient process,” said Professor Forsythe.
“The data suggested high levels of productivity were achieved during elements of the project that were planned well, while opportunities for productivity improvements existed during aspects where the planning process hadn’t been conducted as thoroughly.
“The study also demonstrated how using cranes to lift panels into place is the main passport to productivity, if effective planning processes are employed by project managers to minimise the number of crane lifts required, and by engineering fast crane cycle processes.
“Delivery logistics were also shown to be an important productivity driver. Panels must arrive on-site with a view to minimising double handling. They must therefore be delivered in precise installation order, so as not to waste valuable crane time.
“What’s more, further productivity gains can be made if floor plans are designed with panel layouts that use the same standardised panel size wherever possible, creating a simple and repeatable laying process.”
The results of this research are now available to the construction industry, and, by highlighting the most efficient way forward for project managers, can be used to enhance and guide their planning in the future.
“Our work will support the industry by allowing them to predict the process they will need to follow onsite and will help them to see what sort of efficiencies are achievable,” Professor Forsythe said.
“In turn, this will help them to estimate project costs more confidently and accurately.
“For the forestry industry this can only be good news, as it will help educate decision makers in construction about the significant productivity and cost savings associated with using CLT, thus helping to drive demand.”
You can read the full report online: Productivity in Multi-storey Mass Timber Construction.
