CLT
Cross-Laminated Timber is prefabricated engineered wood that consists of either 3, 5, or 7 layers, with each layer oriented 90 degrees to the previous layer that is bonded using structural adhesives to form large-scale panels. DRJ was the 1st APA certified manufacturer of CLT in the United States to produce this high quality building material. CLT allows flexibility in construction and design compared to steel or concrete.
CLT panels are fabricated by a CNC (Computer Numerical Controlled) and fully manufactured before reaching the job site. The CNC is capable of making high-precision and complex cuts in minutes to the exact size, including door and window openings. By the time the panels are delivered to site, they are stacked in the exact order to how they should be installed, making to building process much faster and efficient. The panels are the ideal building material because of its ability to be used for walls, roof, and floor. The multiple layers of wood creates thermal insulation unlike other structural material.
Cross-Laminated Timber Panels (CLT)
3-Ply 4.125” thick Max Size: 10’ (W) x 41.5’ (L)
5-Ply 6.875” thick Max Size: 10’ (W) x 41.5’ (L)
7-Ply 9.625” thick Max Size: 10’ (W) x 41.5’ (L)
* V1, E2 & E2M1 Grades available per APA-PRG320-2018 Certification
* Douglas Fir fiber used on all grades of CLT panels
Panel Specifications —
Manufacturing Certification: APA PRG 320 Product Report PR-L320
Maximum Panel Size: 10’-0” x 42’-0”
Panel Thickness: 4 1/8”, 6 7/8”, 9 5/8”
Moisture Content: 12 % ± 3%
Wood Species: Douglas fir-Larch
Lumber Grades: DFL #2, DFL #3, 2250Fb-2.0E-1600Ft
Density: ± 34 lb/ft3
GreenGuard Glue Specification: MF Resin – Meets LEED Credit EQ 4.4.1263
CLT Grades: V1, E2, E2M1
Thickness Tolerance: ±1/16” or 2% of panel thickness, whichever is greater
Width Tolerance: ±1/8”
Length Tolerance: ±1/4”
Squareness Tolerance: Length of two panel face diagonals shall not differ more than 1/8”
Straightness Tolerance: Deviation of edges from a straight line between adjacent panel cor-ners shall not exceed 1/16”
Flame Spread: 20 – Meets “Class A” requirements
Smoke Development Classification: 50 – Meets “Class A” requirements
Product Testing
DR Johnson is committed to providing our clients with a structurally safe building product for their project. As part of that commitment, DR Johnson has provided materials for various product tests– both project specific testing requirements & proprietary testing applications – designed to do just that.
Seismic Testing
DRJ Wood Innovations was invited to collaborate on a Bi-National Wood Industry Advisory Committee on a research proposal titled: Development & Validation of a Resilience-Based Seismic Design Methodology for Tall Wood Buildings.
DRJ CLT Panels & Glulams were utilized as the structural elements for the two-story shake table test that took place in San Diego, CA in July of 2017. Initial results from the test provided promising outcomes that will be used to further validate a viable seismic connection design whereas building components can withstand a seismic event with minimal damage/repair. The final validation of the seismic design will be completed through a full scale 7-10 story building being constructed and tested on a shake table (1-2 years out).
Fire Testing
The ASTM E119 test method is intended to evaluate the duration of which a building element will contain a fire, or retain its structural integrity, or display both properties dependent upon the type of building element involved, during a pre-determined fire exposure time.
TEST SAMPLE DESCRIPTION– Typical Floor Assembly (under load): (3) 4’ x 15’ 10” 5-Ply CLT Panels joined together by (1) 4” half lap joint & (1) 8” spline connection joint to make (1) 12’ x 15’ 10” panel. A 2” gypcrete topping slab was applied to (1) side (floor side) of the panel and the underside of the panel (ceiling side) left exposed.
RATING OBTAINED: Unrestrained Loaded 2 Hr.
Fire Testing
The ASTM E119 test method is intended to evaluate the duration of which a building element will contain a fire, or retain its structural integrity, or display both properties dependent upon the type of building element involved, during a pre-determined fire exposure time.
TEST SAMPLE DESCRIPTION– Typical Floor Assembly (under load): (3) 4’ x 15’ 10” 5-Ply CLT Panels joined together by (1) 4” half lap joint & (1) 8” spline connection joint to make (1) 12’ x 15’ 10” panel. A 2” gypcrete topping slab was applied to (1) side (floor side) of the panel and the underside of the panel (ceiling side) left exposed.
RATING OBTAINED: Unrestrained Loaded 2 Hr.
Blast Testing
WoodWorks, in cooperation with the United States Forest Service and the Softwood Lumber Board, conducted a series of live blast tests on three CLT structures at Tyndall Air-Force Base. The results will be used to further expand the use of wood solutions for Department of Defense applications and other blast-resistant construction projects.
TEST SAMPLE DESCRIPTION: (3) two-story, single bay structures with anchorage to an existing concrete slab were constructed using a different grade of CLT per structure. The structures included window and door openings consistent with an actual building. Three shots/blasts were performed to demonstrate the effectiveness of CLT over a spectrum of blast loads.
RESULTS: Initial observations are positive. For the first two tests, results were consistent with expectations. 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.
