Design KLH® – CLT to the NDS

KLH (KLH Massivholz GmbH, Austria) manufactures KLH® – CLT cross-laminated timber. In the US it is recognized under Intertek CCRR-0434, rated to ANSI/APA PRG-320. SPEC Toolbox designs the panels to the NDS, in allowable stress design or LRFD.

The integration covers KLH® – CLT, crosswise-glued spruce laminations face-bonded with a formaldehyde-free polyurethane structural adhesive, in the CV1M1 grade.

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

• Load-bearing floors, roofs and walls.
• Allowable stress design (ASD) or LRFD.
• Dry service (in-service moisture content below 16 percent).
• Compliance with the California and Florida building codes, including the High-Velocity Hurricane Zone.

• An extensive layup range in two orientations. 3-, 5-, 7- and 8-ply build-ups in both TL (floor/roof) and TT (wall) orientations, to 12.6 in. thick, each with effective bending, stiffness and shear in the major and minor directions.
• Large panels. Panels reach 11.5 ft wide and 54 ft long, for wide floor and roof plates and full-storey walls with fewer joints.
• Designed in ASD or LRFD. The reference design values serve allowable stress design or, adjusted with the NDS Table 10.3.1 factors, LRFD; the report also tabulates axial compression capacities for wall panels.
• Tested fire ratings and broad code coverage. Selected layups carry ASTM E119 fire-resistance ratings, and the panels are evaluated to the California and Florida building codes, including the Florida High-Velocity Hurricane Zone.

The KLH panels are available across the SPEC Toolbox CLT modules, worked in ASD or LRFD 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 CCRR-0434.

Design follows the ANSI/AWC NDS under the IBC and IRC. Intertek CCRR-0434 publishes ASD reference design values for KLH® – CLT, rated to ANSI/APA PRG-320: effective bending capacity, bending and shear stiffness, shear and axial compression, in the major and minor directions, for the CV1M1 grade. These are adjusted per NDS Table 10.3.1, without the lumber size factor, with a creep factor of 2.0 applied to long-term deflection; LRFD strengths are obtained by multiplying by the NDS Table 10.3.1 factors. The laminations are Austrian spruce. The evaluation is for dry service (in-service moisture content below 16 percent); fire resistance is determined from the tested layups or by calculation per NDS Chapter 16. The panels also carry California and Florida (including High-Velocity Hurricane Zone) provisions.