Design SmartLam CLT to the NDS

SmartLam (SmartLam, LLC, Columbia Falls, Montana) manufactures cross-laminated timber. In the US it is recognized under ICC-ES ESR-4733, rated to ANSI/APA PRG-320. SPEC Toolbox designs the panels to the NDS, in allowable stress design.

The integration covers SmartLam CLT, at least three planed softwood laminations glued crosswise and face-bonded with a non-formaldehyde polyurethane structural adhesive.

• Five CLT grades: V1M2 (Douglas fir), V2M5 (SPF), V4M1 (SPF-South or Hem-fir), V5M1 (Hem-fir) and V5M2 (Select Structural Hem-fir); the outermost laminations may be replaced by Douglas fir-Larch.
• Balanced layups (3-alt to 9-maxx) and unbalanced layups (4-alt, 6-alt, 8-alt), 4-1/8 to 12-3/8 in. thick, in panels up to 10 ft wide and 52 ft long.
• Applications in floor, roof and wall panels.

At a glance, in the US scope the SmartLam panels support:

• Load-bearing floors, roofs and walls.
• Allowable stress design (ASD).
• Dry service (in-service moisture content below 16 percent).
• Compliance with the California and Los Angeles building codes.

• Five grades across three species groups. V1M2 in Douglas fir, V2M5 in SPF, V4M1 in SPF-South or Hem-fir, and V5M1 and V5M2 in Hem-fir, so the panel grade can be matched to the demand rather than a single default.
• Balanced and unbalanced layups. Balanced layups (3-alt to 9-maxx) for general use, and unbalanced layups (4-alt, 6-alt, 8-alt) for walls and simple spans, each with reference bending, stiffness and shear in the major and minor directions.
• Large panels. Panels are produced up to 10 ft wide, 52 ft long and 12-3/8 in. thick.
• Non-formaldehyde adhesive. The panels are face-bonded with a non-formaldehyde one-component polyurethane structural adhesive.

The SmartLam panels are available across the SPEC Toolbox CLT modules, worked in ASD to the NDS:

• CLT floor, CLT wall and CLT shear wall.

and in the connection modules:

• the screw connection module and the panel-to-panel connection details (spline, butt joint and half-lap);
• CLT floor-to-glulam beam, CLT floor-to-floor and CLT wall-to-wall connections.

Panel behaviour is taken from the integrated database with the reference design values of ESR-4733, using the grade specific gravity for fastener design.

Design follows the ANSI/AWC NDS under the IBC and IRC. ICC-ES ESR-4733 publishes ASD reference design values for SmartLam CLT, rated to ANSI/APA PRG-320: effective bending capacity, bending and shear stiffness, and shear, in the major and minor directions, for the five grades in balanced and unbalanced layups. These are adjusted per NDS Table 10.3.1, without the lumber size or flat-use factor, with a creep factor of 2.0 applied to long-term deflection. The laminations are SPF, SPF-South, Hem-fir or Douglas fir-Larch, the basis for connection design per the NDS. The unbalanced layups are for walls and simple spans and are stamped TOP on the compression side. The evaluation is for dry service (in-service moisture content below 16 percent); fire resistance is determined by calculation per NDS Chapter 16 or by test to ASTM E119. The panels also carry California and Los Angeles building-code supplements.