Design Binderholz CLT to the NDS

Binderholz (Binderholz Bausysteme GmbH) manufactures BBS cross-laminated timber. In the US it is recognized under ICC-ES ESR-4081, developed to ANSI/APA PRG-320. SPEC Toolbox designs the panels to the NDS, using the report’s reference design values, in allowable stress design.

The integration covers the Binderholz CLT BBS, cross-laminated sawn-softwood panels face-bonded with a formaldehyde-free polyurethane structural adhesive, in two formats.

• BBS System Format (BBS SYS): up to about 4 ft wide and 66 ft long, large-finger-jointed, spanning in the major strength direction.
• BBS XL: up to about 11.5 ft wide and 72 ft long.
• 3, 5 and 7-ply, from about 2.4 to 11 in. thick; laminations equivalent to SPF Select Structural with a minimum specific gravity of 0.42, evaluated to ANSI/APA PRG-320.

At a glance, in the US scope the Binderholz BBS 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, Los Angeles, Chicago and Florida Building Codes, including the High-Velocity Hurricane Zone.

• Two formats, including very large panels. BBS XL panels reach about 11.5 ft wide and 72 ft long, and BBS System Format panels are large-finger-jointed for long spans in the major direction, for wide floor and roof plates with fewer joints.
• Reference design values in both directions. The report tabulates effective bending capacity, bending and shear stiffness, and in-plane shear in the major and minor directions, from laminations equivalent to SPF Select Structural (modulus of elasticity 1.5 x 10^6 psi, minimum specific gravity 0.42).
• Formaldehyde-free bond. The panels are face-bonded with a formaldehyde-free polyurethane structural adhesive conforming to ANSI/APA PRG-320.
• Broad US code coverage. The panels were evaluated to the California, Los Angeles and Chicago building codes and the Florida Building Code, including its High-Velocity Hurricane Zone provisions, through the report’s supplements.

The Binderholz BBS 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 exact reference design values of ESR-4081.

Design follows the ANSI/AWC NDS under the IBC and IRC. ESR-4081 publishes ASD reference design values for the BBS panels, developed to ANSI/APA PRG-320: effective bending capacity, bending and shear stiffness, and in-plane shear, in the major and minor strength directions. These are adjusted by the applicable NDS factors (Table 10.3.1) for the load case, without the lumber size factor, and a creep factor of 2.0 is applied to long-term deflection. The laminations are equivalent to SPF Select Structural with a minimum specific gravity of 0.42, which is the basis for connection design per the NDS. The evaluation is for dry service (in-service moisture content below 16 percent). The panels were also evaluated to the California, Los Angeles and Chicago building codes and the Florida Building Code, including its High-Velocity Hurricane Zone provisions, through the report’s supplements.