New Videos of Blast Tests Available

New video footage has been released of blast testing performed on cross laminated timber (CLT) structures, and it’s quite a sight to see.

The Forest Products Laboratory, in cooperation with WoodWorks and the Softwood Lumber Board, led a second round of live blast testing in 2017 at Tyndall Air Force Base in Panama City, Florida.

The charges in the videos were large enough to potentially cause lethal injury, and the structures survived. The objective of these studies was to demonstrate the capability of CLT structures to resist airblast loads, thereby allowing the military to incorporate mass timber materials like CLT into their construction projects.

You can read more about the study here, and see all the blast test videos on the WoodWorks YouTube channel.

Blast Testing, Take Two! An Update on CLT Blast Test Research

The following is an update to a previous LabNotes post.  The updated version was recently featured on the USDA and Forest Service blogs:

All three structures remained standing after the testing – even tests designed to take the structures well beyond their design intent. (Photo courtesy of Air Force Civil Engineering Center AFCEC, Tyndall Air Force Base)

At the USDA Forest Service’s Forest Products Laboratory (FPL), researchers sometimes get a little destructive. They bend and break wood samples of all sizes, and even shoot lumber out of a cannon at 100 miles per hour.

But explosions? That’s a bit out of their wheelhouse. Not that wood can’t handle it. Particularly when it’s used in engineered products like cross-laminated timber, or CLT, which FPL researchers have studied from many angles, including fire performance, use in earthquake-prone regions, and the effects of moisture on CLT. Made of alternating layers of dried lumber boards stacked at 90-degree angles, CLT is exceptionally strong and stable and can be used as walls, roofs, and floors in mid-rise buildings. Continue reading

“The Revolutionary Role of Wood in our Future”: USDA blog post highlights FPL research

The following is a post on the USDA blog highlighting research from the Forest Products Laboratory and the Northern Research Station. The original post can be seen here.

The Revolutionary Role of Wood in our Future

by David N. Bengston, Research and Development, USDA Forest Service
T3 Building in Minneapolis

The T3 Building in Minneapolis was constructed using cross-laminated timber, or CLT. Made from layers of wood crisscrossed and held together by fire-resistant glue, CLT is as strong as structural steel and greatly speeds up construction. (Photo credit: MGA | Michael Green Architecture, DLR Group; photo by Ema Peter; winner of a WoodWorks Wood Design Award)

Some people are just way ahead of their time. In the mid-20th century, when most people thought of wood as an archaic and low-tech material, Egon Glesinger foresaw the revolutionary role it would play in our future, described in his book The Coming Age of Wood.

Scientists in the Northern Research Station’s new Strategic Foresight Group developed a horizon scanning system to identify emerging issues and trends that could be game-changers. A theme that has emerged is the wave of amazing innovations in wood products that could prove Mr. Glesinger right.

For example, wood-based nanomaterials have been produced at the Forest Products Lab (FPL) for more than five years. This renewable, biodegradable material can be used to make computer chips, flexible computer displays, car panels, replacement tendons – for humans – and coatings that keep food fresh longer.

Tall wood buildings, or plyscrapers, are sprouting up across the globe today, built with cross-laminated timber (CLT) and based on research from the FPL and elsewhere. CLT is made from layers of wood crisscrossed and held together by fire-resistant glue. It is as strong as structural steel, greatly speeds up construction, and has a much lower carbon footprint than steel and concrete buildings.

Power-generating wood flooring is being tested at the University of Wisconsin-Madison, a collaboration between the University’s College of Engineering and the FPL. Made mostly from recycled wood pulp, the flooring is chemically treated to produce an electrostatic charge as people walk across it. The charge can power lights and smart building sensor networks, and charge batteries.

Students at the University of Wisconsin-Madison

Students generate electricity while they walk the floors of the student union building at the University of Wisconsin-Madison. Made mostly from recycled wood pulp, the flooring captures the energy of footsteps and turns it into usable electricity. (Photo by Adrienne Nienow)

The list of high-tech innovations in wood products goes on. Cellulose from wood pulp could be cheaper and stronger than petroleum-based polymers currently used for 3-D printing . Fabric made from wood fibers could revolutionize both the textile and forest industry. Wood nails can be driven into solid structural timber without drilling pilot holes. A new process chemically removes lignin from natural wood fibers to produce a transparent wood substitute for glass windows and solar cells. And biodegradable electronics could someday help curb the problem of e-waste.

These and many other marvels of wood product innovation could make the 21st century the century of wood , increasing demand for wood, leading to increased tree planting to meet demand, and the development of markets for wood currently lacking market value. Importantly, thinning overgrown forests with high fuel loads to supply these markets may also decrease wildfire risk.

Wood-based nanomaterials

Wood-based nanomaterials can be used to make electronic components like this one pictured, computer chips, car panels, replacement tendons, and coatings that keep food fresh longer. (US Forest Service courtesy photo)

Turning Up the Heat: Fires Test Performance of Tall Wood Buildings

Wood buildings provide an array of economic and environmental benefits. Interest in capitalizing on those benefits by constructing mid- to high-rise buildings using cross-laminated timber (CLT) is growing. CLT is made from layers of dried lumber boards stacked in alternating direction at 90-degree angles, glued and pressed to form solid panels. These panels have exceptional strength and stability and can be used as walls, roofs, and floors. Additionally, calculations have shown that a seven-inch floor made of CLT has a fire resistance of two hours.

In order for wood structures to rise above six stories without special building official permission, changes to the International Building Code are needed. It’s a tall order, but researchers from the Forest Service’s Forest Products Laboratory (FPL) recently completed a series of fire tests that will address concerns about fire performance of wood buildings and help take them to new heights. Continue reading

Technology Helps Turn Salvaged Trees into Moneymakers

When insect scourges run rampant through forested ecosystems they can leave behind entire stands of dead and dying trees – especially if that scourge is the spruce budworm. In the Upper Midwest, where the spruce budworm infests forests on a cyclic 30-50 year pattern, forest managers oftentimes use salvaged logs from the dead and dying trees to produce low-value wood products, such as wood pulp, or merely count the dead trees as a loss and leave them standing.

Spruce budworm mortality,
Chequamegon–Nicolet
National Forest, Summer
2014 (Steven Katovich, USDA
Forest Service, Bugwood.org).

But Forest Products Laboratory (FPL) researchers developed ways to evaluate the quality of salvaged wood and sort out the higher-quality wood for production of cross-laminated timber (CLT) – a high-value wood product that can increase forest revenues. “We’re at the point of demonstrating commercially available technologies,” said FPL engineer Robert Ross, “and the idea that we can take high-grade material out [of dead tree stands].” Continue reading