by Web Editor | Nov 8, 2017 | News
WoodWorks, in cooperation with the USDA Forest Service Forest Products Lab and Softwood Lumber Board, conducted a second series of blast tests on three existing two-story, single-bay cross-laminated timber (CLT) structures at Tyndall Air Force Base—the same structures involved in a series of initial blast tests performed in 2016. While a full analysis will be published early next year, on-site observations are decidedly positive. All structures remained intact under significant explosive loading well beyond their design capacity.
“Last year, we tested the structures under their own self-weight,” said Bill Parsons, VP of Operations for WoodWorks. “Those tests were successful and, this year, we built on that effort by testing whether the design methods established as a result of those initial tests needed to be adjusted when the buildings carried typical gravity loads and included different connection configurations, increased panel thickness, and alternate mass timber wall systems.”
Four tests were performed covering a spectrum of blast loads. For tests one and two, the size of the blast load and configuration of the structures were the same as prior testing, except the structures had axially-loaded front panels. The loads applied were intended to simulate conditions associated with a 5-story residential or office building. For tests three and four, different variables were altered on each of the buildings. One building used 5-ply CLT front wall panels, the second used off-the-shelf prefabricated angle brackets, and the third included nail-laminated timber (NLT) front panels. Reflected pressure, peak deflections, and panel acceleration were recorded at front and side faces in order to compare results to previous testing.
As with the tests performed in 2016, peak recorded deflections were consistent with pre-test predictions indicating the effectiveness of design assumptions and methodology in predicting elastic response of CLT to dynamic loads. The second test also indicated a controlled response in which localized panel rupture was observed but connection integrity and load carrying ability were not compromised for any of the loaded structures. Of particular note, all three structures remained standing following the fourth and largest blast, intended to take the structures well beyond their design intent. While panel rupture was expected and observed on all front and side wall panels, the buildings maintained enough residual capacity to remain intact and safe to enter.
From The Construction Specifier: https://www.constructionspecifier.com/woodworks-leads-successful-blast-testing-loaded-mass-timber-structures/
by Web Editor | Dec 19, 2016 | News
Videos are now available showing a series of live blast tests on three cross-laminated timber (CLT) structures at Tyndall Air Force Base, conducted by WoodWorks in cooperation with the US Forest Service and Softwood Lumber Board. Post-test observations were exciting. All structures remained intact and matched modeling predictions with acceptable levels of damage under significant explosive loading. The results of this testing will be used to further expand the use of wood solutions for Department of Defense applications and other blast-resistant construction. Watch the videos here: https://bit.ly/2hwVE1g
The CLT structures—each two-story, single-bay structure with anchorage to an existing concrete slab—were constructed in full by Lendlease over a period of eight days. Each structure was constructed using a different grade of CLT (i.e., grade designations V1, E1 and V4 per ANSI/APA PRG-320 provided by DR Johnson, Nordic and SmartLam, respectively) and included window and door openings (with doors provided by American Direct) consistent with an actual building. Self-drilling screws provided by MyTiCon and adhesive anchors provided by Hilti were utilized in concert with angle steel to connect the constituent panels of each structure.
Three shots were performed to demonstrate the effectiveness of CLT over a spectrum of blast loads. The first two shots were designed to stress the CLT structures to within their respective elastic limits. The third shot was designed to push the structures beyond their elastic limits such that post-peak response could be observed. Reflected pressure and peak deflections were recorded and will be used to thoroughly document the response of the structure in time, and support a design methodology for predicting elastic response of CLT under dynamic loads.
Initial observations deriving from these tests are positive. For the first two tests, peak recorded deflections were consistent with pre-test predictions, indicating the efficacy of the design assumptions and supporting design methodologies. Results from the third test indicated a controlled response in which localized panel rupture was observed but connection integrity and load carrying ability were not compromised for any of the three structures. Over the next couple months, WoodWorks will be working with Karagozian & Case, Inc. and the University of Maine to thoroughly post-process and analyze the results of these tests.
From Business Wire: https://www.businesswire.com/news/home/20161215005337/en/WoodWorks-Leads-Blast-Testing-Project-Cross-Laminated-Timber
by Web Editor | Nov 21, 2016 | News
WoodWorks, a proponent of large-scale wood construction in the U.S., launched an updated version of its free carbon calculator, adding more options for buildings made from cross-laminated timber (CLT) and other mass timber products. The addition reflects rising interest in large scale wood building construction.
WoodWorks, which receives finding from the U.S. Department of Agriculture as well as timber companies and forest products manufacturers, promotes use of wood products as a means to store carbon, instead of building materials such as cement and steel that require fossil fuel energy to manufacture, a move that can help reduce greenhouse gases.
“The carbon calculator is a useful tool for building owners and designers who’d like to gain insight on the environmental value of alternate designs,” said Bill Parsons, Senior National Director of the Architectural & Engineering Solutions Team at WoodWorks. “It also provides information that allows them to express the carbon benefits of their wood building projects.”
To calculate the carbon benefits of a wood building, users access the carbon calculator at www.woodworks.org/carbon-calculator and enter nominal wood volume information. The calculator then estimates:
• How much time it takes U.S. and Canadian forests to grow that volume of wood
• The amount of carbon sequestered in the wood products, and
• Greenhouse gas emissions avoided by not using more fossil fuel-intensive materials.
• It also uses the U.S. Environmental Protection Agency’s Greenhouse Gas Equivalencies Calculator to equate the total carbon benefit to number of cars off the road and home operational energy.
From Woodworking Network: https://www.woodworkingnetwork.com/news/woodworking-industry-news/free-carbon-calculator-shows-how-much-co2-wood-construction-saves?ss=news,news,woodworking_industry_news,news,almanac_market_data,news
