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

Researchers to Use Wood-infused Concrete in California Bridge

This transmission electron microscope shows cellulose nanocrystals, tiny structures derived from renewable sources that have been shown to increase strength of concrete. Image: Purdue Life Sciences Microscopy Center

Civil and Structural Engineer (CSE) Magazine recently published an article about an exciting advancement in the practical application of cellulose nanomaterials – using nanocellulose as an additive to concrete.

Purdue University researchers, who have been long-time partners of the Forest Products Laboratory, have been studying whether concrete is made stronger by infusing it with microscopic-sized nanocrystals from wood. Their research is now moving from the laboratory to the real world with a bridge that will be built in California this spring.

“Simply getting out there where people can actually drive on it, I think, is a huge step because you can’t just say it’s a lab curiosity at that point. It has real-world implications,” said Jeffrey Youngblood, a Purdue professor of materials engineering.

Read the full article here to find out how minuscule wood particles can make concrete stronger, and the many added benefits researchers are discovering through this project.

Collaboration Yields U.S. Patent for Green Building Materials

University of Colorado Denver (CU) professor and architect Julee Herdt, in collaboration with John Hunt of the Forest Products Laboratory (FPL), and Kellen Schauermann, architect, CU alumnus and research assistant, recently received a patent for environmental construction materials.

BioSIPs structural panels for wall, floor, and roof constructions.

The patent includes software and material science for converting 100 percent waste fibers, such as post-consumer wastepaper, agriculture residues, flowers, hemp, wood scraps, noxious weeds, dead trees, and other unwanted cellulose, into high-strength construction boards.  Using the technology, these dense yet lightweight and strong boards are bent and flexed into a virtually limitless array of shapes, from flat to complex, for making energy-efficient, non-off-gassing building materials, and buildings. The software also allows for associated manufacturing, economic, and recycling scenarios to be studied while the waste fiber eco-products are being designed. Continue reading

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