In August 2017 the TallWood Design Institute began phase two testing for an innovative new engineered wood product: the mass plywood panel (MPP).
Freres Lumber Company of Lyon, Oregon is excited about introducing the new-to-market, veneer-based product. It’s something Tyler and Kyle Freres have been dreaming about since a 2015 trip to Austria.
“We visited a few state-of-the-art facilities that were producing cross-laminated timber (CLT) really efficiently, and we felt we could achieve the same kind of performance attributes using veneer,” Freres says.
As soon as they returned to Lyons, they started gluing panels together and experimenting with the new panel product. He says that working with Oregon State University is invaluable in helping his company refine the product.
Arijit Sinha, associate professor of Renewable Materials at Oregon State, leads the testing, and says phase one went extremely well.
“During our first round of testing, we helped Freres identify the lay-up pattern they want to use, and now we’re testing an optimized layup at different thicknesses that they will eventually take to market.”
Phase two includes bending tests to investigate the strength and stiffness of the product. Later, connections, acoustic performance characteristics and a shear wall application of the product will also be tested.
Once on the market, MPP, like CLT, can be used as a substitute for traditional building materials, providing much lower embodied energy and greater carbon sequestering properties than concrete and steel.
Freres says the advantages of MPP are that is uses 20-30 percent less wood than CLT, large-format panels can be manufactured at the production facility in order to minimize waste and labor on job sites, the light-weight of the panels can help save on transportation costs and logistics during construction and more.
“We are a good example of a family business working within our rural community to come up with something new and innovative,” Freres says. “It’s also been great to have the experts and the researchers at the TallWood Design Institute working with us on this project. We have a very close relationship, and appreciate all the extra hands involved in producing MPP.”
Bending tests verify the performance of MPP in a horizontal application such as a beam or slab element. The span tests determine MOE (modulus of elasticity) and MOR (modulus of rupture, bending strength) for MPP. They show failure progression – where the stresses are going and how the panel is responding to the loads. Short span tests provide data on the shear properties of MPP. Shear loads tend to produce a sliding failure on material parallel to the direction of the force.
Dowel Bearing Tests
Dowel bearing test results are used to analyze the crushing behavior of wood or wood- composite products beneath a fastener. The data obtained can be used to establish design values for wood-based connections.
Withdrawal testing quantifies the capacity of MPP to hold in a nail or screw. Together with the dowel bearing test results, this baseline data will also inform the development of connections for MPP systems.
The connection testing examined how wall-to- oor connections perform. Tests focused on three common connector types: ABR 105, HGA10KT (an L-shaped bracket) and self- tapping screws. Two different types of loading – monotonic (single, consistent force) and cyclic (cycles of up and down forces) were used. The tests were performed in four different directions depending on the grain.