Glulam Design Software for Eurocode 5
Design Glulam elements including beams, columns, beam penetrations & fire design according to Eurocode 5. Analyze bending, shear, and stability for GL24, GL28, and GL30 grades in seconds.
The Design of Glulam for European Projects
Glue Laminated Timber (Glulam) allows for spans and geometries that solid timber simply cannot match. By laminating stress-graded timber stock, Glulam offers higher strength, consistency, and architectural beauty.
The SPEC Toolbox Glulam Calculators remove the complexity of Eurocode 5 (EN 1995-1-1) verification. Whether you are designing a simple roof ridge beam or a heavy-duty column, this tool automates the interaction checks, stability factors, and material properties for all standard European Glulam grades (EN 14080).
What This Calculator Does
This tool performs a complete structural analysis of Glulam beams and columns under gravity and wind loads. It verifies:
About : Glulam Design
Technical Guide: Glulam Design to Eurocode 5
1. Size Effect (kh)
Unlike steel, timber is stronger in smaller volumes. Eurocode 5 accounts for this with the Size Effect Factor (kh).
For depths less than 600mm, the characteristic bending and tensile strength is increased.
$$k_h = \min \left( \left(\frac{600}{h}\right)^{0.1}, 1.1 \right)$$
Our calculator automatically updates this factor as you adjust the beam depth, ensuring you get the full benefit of the material’s efficiency.
2. Lateral Torsional Buckling (LTB)
Deep, slender Glulam beams are prone to buckling sideways under load.
The calculator determines the Relative Slenderness (λrel,m) and applies the reduction factor (kcrit).
- Tip: You can toggle lateral restraints (e.g., “Restrained at supports only” or “Fully restrained by decking”) to optimize your design and increase capacity.
3. Material Hierarchy (EN 14080)
We support the full range of harmonized European Glulam grades:
- Combined Glulam (GL24c, GL28c, GL30c): Uses stronger laminations on the outer faces (tension/compression zones) and lower grade timber in the core. Efficient and cost-effective.
- Homogeneous Glulam (GL24h, GL28h, GL30h): Uses the same high-grade timber throughout. Used when the aesthetic of the edge face is critical or for specific stress concentrations.
Key Formulas & Parameters
Combined Axial & Bending:
For columns or beams with axial loads, the interaction formula is critical:
$$\left(\frac{\sigma_{c,0,d}}{k_c \cdot f_{c,0,d}}\right) + \left(\frac{\sigma_{m,y,d}}{f_{m,y,d}}\right) \le 1.0$$
The tool checks both “Squared” and “Linear” interaction limits as required by Clause 6.3.2.
Shear Verification (kcr):
Eurocode 5 requires a reduction in shear width to account for fissures (cracks) in the timber.
- kcr = 0.67$ (Standard value for solid timber/glulam per NA).
- This effectively ignores 33% of the beam width for shear checks, a conservative but mandatory safety measure.
Service Classes:
- Service Class 1: Heated indoor environments (kdef = 0.6$).
- Service Class 2: Covered exterior / unheated (kdef = 0.8$).
- Service Class 3: Exposed to weather (kdef} = 2.0$).
- Note: Changing the Service Class significantly impacts long-term deflection.
Tutorials
Beam-to-Column Connection Design
Beam-to-Column Connection Tackle the complexity of Beam-to-Column joints in this focused tutorial. We demonstrate how to replace complex bespoke steelwork with smart screw arrangements. Using the Screw Module, we verify the capacity of inclined screw groups to handle significant shear loads directly at the support interface.
Key Screw Benefits:
Crossed-Screw Configurations: Shows how arranging screws in crossed pairs (X-formation) significantly boosts stiffness.
Ductility & Safety: detailed look at how modern structural screws provide necessary ductility for safe, predictable failure modes.
Slab-to-Beam Connection Design
Timber Column Calculator
In this video, we’ll walk you through designing Timber Column using tributary area loads, following Eurocode 5 and AS1720 standards. We start by selecting the right material that not only meets the structural demands but also fits the design requirements. Then, we detail how to input the loads from the columns above and the supported beam, ensuring every force is accounted for. An essential part of this process is incorporating lateral loads from wind. We also demonstrate how to optimize the cross-section to enhance both efficiency and performance.
At CLT Toolbox, we’re passionate about #masstimber – it’s sustainable, innovative, and changing the way we build. We love how it packs strength, durability, and environmental benefits into one smart package. In our video, we break down the process with straightforward tips and clear explanations so you can put these methods into practice on your own projects. If you’re ready to move your design work into the future, stick around and let’s dive in together.
Beam Notch Calculator
Design & Verification of a GLT Beam Notch According to EC5 with CLT Toolbox
The key question: does the reduced cross-section provide enough capacity, or is reinforcement with screws required?
Here’s what we covered in this video:
– How to check notch capacity using EC5
– When and how to use reinforcement screws based on ETA data from suppliers
– Introduction to screw geometry inputs
– How screw position, orientation, and quantity can optimise the design
A practical guide to achieving safe and efficient timber connections. Would love to hear your thoughts or experiences with similar designs!
Vertical Bracing Member Design
Learn how to use the CLT Toolbox Member Calculator to design a vertical bracing diagonal. We’ll walk you through importing analysis results from external tools, identifying maximum tension and compression forces, and selecting the right inputs—grades, sections, code specifics, and forces. Plus, we’ll break down the results, covering material properties and all key design checks. CLT Toolbox is here to be your partner in designing timber projects!
Timber Column Calculator
In this video, we walk you through designing Timber Column using tributary area loads, all in line with Eurocode 5 guidelines. We begin by selecting the right material and national annex, ensuring your starting point is solid and up to code. Next, we show you how to input the appropriate loads from the columns above as well as from the supported beam. We also cover the crucial step of adding lateral wind loads. As we progress, you’ll see how to optimize your column’s cross-section for both strength and efficiency.
At CLT Toolbox, we’re passionate about mass timber, it’s sustainable, innovative, and changing the way we build. We love how it packs strength, durability, and environmental benefits into one smart package. In our video, we break down the process with straightforward tips and clear explanations so you can put these methods into practice on your own projects. If you’re ready to move your design work into the future, stick around and let’s dive in together.
Vertical Bracing Member Design
Learn how to design vertical bracing diagonals using the CLT Toolbox Member calculator. This video walks you through importing force data from external analysis tools, identifying maximum tension and compression forces, and selecting the correct inputs—grades, sections, design codes, and applied loads. Get a clear overview of the results, including material properties and design checks based on Eurocode.
Mass timber is transforming modern construction with its sustainable, low-carbon footprint—offering a powerful alternative to traditional building materials. CLT Toolbox is here to support you every step of the way in designing your dream project with confidence and precision.
GLT Beam Penetration Design
The GLT Beam Penetration Calculator simplifies the design process for structural beams with penetrations. The features of this calculator are as follows:
Design Standards: Adheres to Eurocode (prEN 1995:2023) or AS 1720:2010/NZ WDG Ch12.6.
Material Input Options: Choose between manual input or a preferred partner supplier.
Penetration Shapes: Covers rectangular and circular-shaped penetrations up to five penetrations.
Beam Type: Focuses exclusively on simply supported beams.
Load Combinations: Offers input design forces. Strength Verification: Includes built-in checks for geometric limitations, tension capacity, flexural capacity, and shear capacity.
Reinforcement Check: Provides screw reinforcement geometry and design checks.
Frequently Asked Questions
Can I design tapered beams?
This module is for Prismatic (Straight) members. For tapered, curved, or pitched-cambered beams, please use our advanced Complex Beam Module (coming soon), as these require specialized stress checks for tension perpendicular to grain ($k_{vol}$).
Does it check bearing?
Yes. The calculator verifies the Compression Perpendicular to Grain ($f_{c,90,d}$) at the supports. You can adjust the bearing length ($l_b$) to ensure the beam doesn’t crush the wall plate.
Is Fire Design included?
This module covers “Cold” design. For fire verification (R30, R60), use the Beam Fire Calculator to determine the effective reduced cross-section ($d_{eff}$) after charring.
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