Glulam Design Software for NDS 2018

Supplier & Code Integration

Effective glulam beam design begins with the correct application of AWC NDS material parameters and load factors. Our platform integrates supplier-specific glulam data with the National Design Specification for Wood Construction (AWC NDS 2018), enabling fast and reliable structural verification of timber beam elements.

Material grades are evaluated using NDS design parameters. Load combinations are generated according to ASCE 7-16, while the calculator supports Allowable Stress Design (ASD) methodology together with adjustments for moisture conditions and temperature factors.

Analytical Model for Glulam Beams

• Elastic Beam Theory

Glulam beams are analyzed using classical Euler–Bernoulli beam theory. The beam is treated as a linear elastic element where plane sections remain plane during bending. This approach provides accurate evaluation of internal forces, stresses, and deflections.

• Section Properties

The structural behavior is determined from the beam geometry and material grade. Key properties such as moment of inertia, section modulus, and effective section area are automatically calculated to evaluate stiffness and strength.

• Stability Considerations

Slender beams may experience lateral stability effects when subjected to bending. The design incorporates restraint conditions and effective unbraced length parameters to ensure reliable structural performance in accordance with NDS stability provisions.

Structural Performance Checks

The calculator evaluates the main structural limit states according to AWC NDS 2018 provisions.

• Bending Resistance

Verification of bending stresses against the allowable bending stress of the glulam section. The tool calculates the maximum bending moment and corresponding stress utilization based on ASD design values.

• Shear Resistance

Shear stresses within the beam cross-section are checked against the allowable shear strength of the glulam member to ensure safe transfer of vertical loads.

• Stability Check Due to Bending

Glulam beams may experience lateral instability when bending about the major axis. The calculator evaluates the restraint system and effective length parameters to verify stable structural behavior.

• Deflection Verification

Serviceability performance is assessed by calculating beam deflection under applied loads. The resulting deformation is compared against allowable span limits to ensure adequate stiffness and service performance.

Supplier & Code Integration

Effective glulam column design begins with the correct application of AWC NDS material parameters and adjustment factors. Our platform integrates supplier-specific glulam data with the National Design Specification for Wood Construction (AWC NDS 2018), enabling reliable structural verification of timber compression members.

Material grades such as GL24h, GL28h, and other glulam classes are evaluated using NDS design parameters. Load combinations are generated according to ASCE 7-16, while the calculator supports Allowable Stress Design (ASD) methodology together with adjustments for moisture conditions (Cm) and temperature factors (Ct).

Analytical Model for Glulam Columns

• Elastic Member Analysis

Glulam columns are modeled as linear elastic members following classical structural mechanics principles. Axial compression forces, bending moments caused by eccentric loads, and interaction effects are evaluated using AWC NDS design procedures.

• Section Properties

The structural behavior is determined from the column geometry and timber grade. Important properties such as section modulus, moment of inertia, and radius of gyration are automatically calculated to determine the stiffness and resistance of the member.

• Load Eccentricity Effects

Columns frequently experience eccentric loading from connecting beams or framing elements. The calculator considers eccentricities in both principal directions, resulting in bending moments that are combined with axial compression during design verification.

Structural Performance Checks

The calculator evaluates the main structural limit states according to AWC NDS 2018 provisions.

• Bending Verification

Bending stresses caused by load eccentricities are checked about both the major and minor axes of the column cross-section. The calculated stresses are compared with the allowable bending stress of the glulam member.

• Compression Verification

Axial compression forces acting on the column are verified against the allowable compressive stress parallel to grain. This ensures the column can safely carry vertical loads transferred from beams and upper structural elements.

• Combined Actions Verification

When axial force and bending moments occur simultaneously, the interaction between these actions is checked according to NDS interaction equations for combined bending and compression. This verification ensures safe behavior under realistic loading conditions.

• Buckling Verification

Slender columns are susceptible to instability. The calculator evaluates column buckling using effective length parameters, slenderness ratios, and NDS column stability factors to determine the allowable compressive capacity.

• Stability Checks

Additional stability verification evaluates member slenderness ratios and restraint conditions to ensure the column remains stable under combined compression and bending effects.

Advancing Structural Connection Design for Glulam

While the National Design Specification for Wood Construction (AWC NDS 2024) provides the fundamental design framework for timber structures in the United States, modern glulam connection design often requires advanced modeling and manufacturer-specific material data to ensure reliable structural performance.

Advanced Yield Modeling

SPEC Toolbox implements the NDS Yield Limit Equations to evaluate the behavior of dowel-type fasteners in glulam connections. These equations predict the governing fastener failure modes and determine the connection load-carrying capacity under combined shear, tension, and bending effects.

Manufacturer Data Integration

The platform integrates supplier-specific glulam properties, allowing engineers to perform connection design using real manufacturer material data and NDS design parameters.

Simplified Structural Joint Design

SPEC Toolbox streamlines complex connection calculations into a clear and efficient engineering workflow for common glulam connection scenarios.

Supported Connection Type

The U.S. design module currently supports:

Dowel and Bolt Connections

These connections are evaluated according to AWC NDS dowel-type fastener provisions, using the NDS Yield Limit Equations to verify the structural capacity of both the timber member and the fasteners.

The “Global-Local” Connection Library

SPEC Toolbox allows engineers to combine glulam suppliers with industry-leading fastener systems, enabling realistic connection design that reflects both material properties and hardware performance.

Universal Fastener Selection

Connections can be designed using dowel-type fasteners such as bolts and dowels, evaluated using NDS yield equations and adjustment factors including load duration, moisture conditions, temperature effects, and time-effect factors.

Verified Compatibility

Connection designs can be evaluated with glulam materials from manufacturers including:

Binderholz, Mercer, Nordic, and SmartLam, ensuring accurate structural verification using real manufacturer data.

Automated Structural Checks

The calculator automatically evaluates connection performance through several key design verifications:

• Geometric Check – verification of spacing, edge distances, and layout requirements

• Yielding Resistance – capacity based on NDS yield limit equations

• Row Shear Resistance – verification of shear capacity along fastener rows

• Group Tear-Out Resistance – evaluation of potential splitting or tear-out failures

• Net Tension Resistance – verification of remaining net section capacity of the timber member

These automated checks ensure that glulam connections satisfy AWC NDS 2024 design requirements while maintaining safe load transfer between connected structural elements.

If you’re looking to design CLT on your next project, then SPEC Toolbox has you covered!