The scene is iconic, Juliet on her balcony calling out into the night, “O Romeo, Romeo, wherefore art thou Romeo?”, and Romeo calling up from the garden below to his star-crossed love, desperation in his heart. It is a scene that is known nearly all around the world. To many, it is what gives balconies their romantic appeal.
What a different scene it would have been if Shakespeare was not only a writer but an engineer who understood the difficulties of balcony architecture and construction. Balconies would be viewed with less rosy lenses if Shakespeare, instead of giving Romeo “love’s light wings,” gave him a balcony with moisture-driven rot and the moment he began to climb towards Juliet, the structure unmoored and flattened him under piles of destabilized building materials.
Although it may be lighthearted to imagine Romeo in a different balcony scenario, between 2001 and 2016 there have been approximately 239 balcony and deck collapses in the United States alone. In just two high-profile balcony collapses in Berkeley, CA and Chicago, IL, a total of nineteen fatalities resulted. As buildings age, construction defects become fatal defects.
The following is a press release from the U.S Endowment for Forestry and Communities.
The U.S. Endowment for Forestry and Communities (Endowment), in partnership with the United States Department of Agriculture’s Forest Service (USFS), today announced the initiation of the Mass Timber University Grant Program (Grant Program) and related Request for Proposals (RFP) to promote the construction of mass timber buildings on institutions of higher learning campuses across the U.S. The intent of the Grant Program is to inspire interest in and support for mass timber products among the architectural, developer and building communities as well as the public, by showcasing them in highly-visible projects on university campuses.
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.
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 →
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.