10 Nov Cross-Laminated Timber Blast Testing Program
As part of a Wood Innovation Grant funded by the U.S. Forest Service and the Softwood Lumber Board, Karagozian & Case, Inc. (K&C) worked with WoodWorks, the University of Maine (UMaine), and the Air Force Civil Engineer Center (AFCEC) to develop and execute a two-phase testing program aimed at demonstrating the blast-resistance capability of cross-laminated timber (CLT), a massive timber product recently introduced into the North American market.
The first phase of testing was performed at UMaine to investigate the out-of-plane response of CLT panels through application of a uniform quasi-static load (Fig. 1). Grade, ply number, and connections were varied over 31 tests. The results of this testing compared well with K&C’s pre-test analyses (Fig. 2). K&C used this data to develop a CLT resistance function capable of being used in SDOF dynamic analysis.
Fig. 1 Quasi-Static Testing of CLT Panels
Fig. 2 Quasi-Static Load-Displacement Data Comparison
Using this analytical model, K&C designed and detailed three two-story, single-bay CLT test structures. Each structure was constructed using a different grade of CLT and included window and door openings. The CLT structures were constructed in less than eight days at Tyndall AFB and subsequently exposed to three live blast shots to demonstrate the effectiveness of CLT over a spectrum of blast loads.
The live blast tests demonstrated CLT’s ability to effectively resist blast loads. In addition, pressure and displacement data recorded during the tests compared well with K&C’s pre-test prediction calculations. K&C is currently working with the U.S. Army Corps of Engineers and AFCEC to write a technical report that can be used by other engineers to design CLT structures for blast loads based on the results of these tests.
For more information on this project and our other testing capabilities, please contact us