Design Mercer Glulam to the NDS

Mercer (Mercer Mass Timber, Conway, Arkansas) manufactures glued laminated timber. In the US it is recognized under APA Product Report PR-L348. SPEC Toolbox designs the beams and columns to the NDS, in allowable stress design.

The integration covers Mercer glulam, in Southern pine, manufactured to ANSI A190.1 with ANSI 117 layup combinations, grouped by role.

Beam stress classes

• 24F-V3 and 24F-V8, and 30F-E1/SP and 30F-E2/SP, in unbalanced (simple-span) and balanced (continuous or cantilever) layups.

Column combinations

• 47, 48, 49 and 50 (N2M, N2D, N1M and N1D14), for members stressed primarily in compression or axial loading.

Sections run to 20 in. wide, 43 in. deep and 65 ft long. Uses include beams, headers, rafters, purlins and columns.

At a glance, in the US scope the Mercer glulam supports:

• Beams and columns.
• Allowable stress design (ASD).
• Dry service, with wet-use factors available for wet conditions.

• High-strength Southern pine beams. Beam stress classes from 24F to 30F (30F to 3,000 psi bending and 2.2 x 10^6 psi modulus of elasticity), in balanced and unbalanced layups for simple-span or continuous members.
• Column combinations. The 47 through 50 combinations reach 2,300 psi compression parallel to grain, for heavy columns and axial members.
• Large sections. Sections reach 20 in. wide, 43 in. deep and 65 ft long, for long-span beams.
• Fire design per NDS Chapter 16. Exposed members may be designed for fire per NDS Chapter 16 or IBC Section 722.1.

The Mercer glulam members are available across the SPEC Toolbox member-design modules, worked in ASD to the NDS:

• Timber beam and Timber column.

and in the connection modules:

• the screw connection module and the CLT floor-to-glulam beam connection.

Member behaviour is taken from the integrated database with the reference design values of PR-L348, using a specific gravity of 0.55 for fastener design.

Design follows the ANSI/AWC NDS under the IBC and IRC. APA Product Report PR-L348 publishes ASD allowable design values for Mercer glulam beams and columns, manufactured to ANSI A190.1 with ANSI 117 combinations: bending, modulus of elasticity, shear, compression perpendicular and parallel to grain, and tension. These are adjusted per NDS Section 5.3 and Table 5.3.1, among them the volume factor, the flat-use factor and beam and column stability. The species is Southern pine (specific gravity 0.55). Tabulated values are for normal load duration and dry service, with property-specific wet-use factors for wet conditions; fire resistance is determined per NDS Chapter 16 or IBC Section 722.1.