Research at FPL often works toward moving new or improved wood products into mainstream use. Cross-laminated timber (CLT) is one such product. CLT is a solid panel made of bonded layers of lumber intended for roof, floor, or wall applications. It is a highly “green” material made from an abundant renewable resource; it also sequesters carbon, has low embodied energy, and has excellent aesthetic, structural, and thermal properties.
Real-life data of wood products in-use are valuable in helping new products gain acceptance, but it can be hard to come by.
CLT has been used in Europe for more than 15 years, says FPL research physical scientist Samuel Glass, but has only recently been produced and designed into structural systems in North America. “FPL has been assisting in removing technical barriers to the use of CLT and trying to develop interest for its use in the United States,” says Glass, “but until now we’ve had only computer simulations to work with.”
As luck would have it, a construction project using CLT recently cropped up not far from FPL, giving Glass the opportunity to study the product in a realistic environment.
Promega Corporation, a leader in providing innovative solutions and technical support to the life sciences industry, is using CLT in their new client and staff center, called The Crossroads. The project is the first large-scale commercial installation of CLT in the United States using CLT manufactured in North America.
David Rousseau from Archemy Consulting, design consultant for the project, explained that the company wanted The Crossroads to be a unique space, and CLT intrigued them because it is a new and innovative material that also offered the warm aesthetic they wanted to create. “Plus, we wanted to have a high quality, exposed roof deck with long spans and minimum on-site construction complexity,” said Rousseau. “CLT met the criteria.”
When FPL researchers heard about the construction project, they knew it presented a valuable opportunity. “As with any new building system, it is important for potential users to have information on how CLT is installed and how it performs,” says Glass. “Partnering with Promega is giving us the chance to develop that information based on real-life data.”
Glass says the objectives of the research are two-fold. “We documented the CLT installation process with both photo and video to develop educational materials for the design and construction community,” said Glass. “Also, we set up a monitoring system to collect data on in-service moisture and temperature conditions.”
Glass and his team installed wireless, battery-operated sensors in the CLT panels immediately after they were installed (in one case, even before) and monitoring started during construction. The sensors are positioned in various locations on both the top and bottom of the panels and are measuring wood moisture content, temperature, and relative humidity.
Glass will collect the data for a two-year period, and the results will give those considering using CLT for their projects a sense of how their building will perform, particularly in commercial applications.
“There is a perception that wood is less durable than steel or concrete, and solid data will help promote the use of wood,” says Glass. “In a well-designed and constructed building, wood performs comparably to steel and concrete and can be a better option for those with a desire to focus on green building materials and techniques.”
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