Bend Test – Timber Structures

Wood-based panels used in structural applications must be capable of carrying loads without excessive deformation or premature failure. Variations in material composition, manufacturing processes, density and panel construction can significantly influence bending performance, making reliable mechanical testing essential when assessing products intended for load-bearing applications.

Insufficient bending strength or stiffness can result in excessive deflection, structural performance issues and difficulties demonstrating that a material is suitable for its intended application. Manufacturers and material developers therefore require accurate test data to characterise mechanical performance and support structural design values.

BS EN 789 provides recognised test methods for determining the mechanical properties of commercial wood-based panels intended for use in load-bearing timber structures, including their bending properties. The results can be used in the determination of characteristic values for structural applications.

What BS EN 789 Bend Testing Involves

BS EN 789 specifies methods for determining mechanical properties of wood-based panel products intended for structural applications. These include bending, compression, tension and shear properties.

Bend testing evaluates the response of a representative panel specimen when subjected to a controlled bending load. The resulting load and deflection data can be used to characterise the stiffness and strength of the material.

Testing can be applicable to structural wood-based panel products such as:

• Plywood
• Oriented strand board (OSB)
• Laminated veneer lumber (LVL)
• Fibreboard
• Particleboard
• Other wood-based panels intended for load-bearing applications

Depending on the testing programme and product requirements, results can provide information relating to:

• Bending strength
• Modulus of elasticity in bending
• Load-deflection behaviour
• Maximum load
• Failure characteristics
• Mechanical performance in different panel directions

The mechanical properties determined using BS EN 789 are intended to support the calculation of characteristic values used to obtain material design values for structural applications.

Methodology

At Impact Solutions, bend testing of wood-based panels can be carried out using calibrated mechanical testing equipment in accordance with BS EN 789.

A typical testing programme includes:

1. Selection and preparation of representative test specimens from the wood-based panel product.
2. Conditioning and measurement of specimens in accordance with the applicable test requirements.
3. Determination of relevant specimen dimensions and, where required, moisture content and density.
4. Positioning of the specimen within the bending test arrangement.
5. Application of a controlled load to the specimen.
6. Measurement of load and corresponding deflection during testing.
7. Continuation of loading to determine the required bending properties and observe failure behaviour.
8. Calculation of relevant mechanical properties from the recorded test data.
9. Comprehensive reporting of test conditions, results and observations.

Testing is performed under controlled laboratory conditions to provide accurate, repeatable and reliable mechanical performance data.

Relevant Industry Applications

BS EN 789 bend testing is relevant to:

• Structural plywood
• Oriented strand board (OSB)
• Laminated veneer lumber (LVL)
• Particleboard
• Fibreboard
• Engineered wood products
• Structural building products
• Flooring and decking systems
• Roofing and wall sheathing
• Timber frame construction
• Product development and material assessment

BS EN 789 is specifically concerned with commercial wood-based panel products for use in load-bearing timber structures. It is not intended as a routine quality control test.

Benefits of BS EN 789 Bend Testing

• Determines the bending performance of structural wood-based panels
• Provides bending strength and stiffness data
• Supports determination of characteristic mechanical properties
• Assists with structural material assessment and product development
• Enables comparison between different panel constructions and materials
• Supports engineering and structural design requirements
• Helps manufacturers demonstrate the performance of load-bearing panel products
• Provides reliable mechanical data for technical documentation and product assessment

Need to determine the bending performance of your structural wood-based panels?

Contact Impact Solutions to discuss bend testing to BS EN 789 and obtain reliable mechanical performance data for wood-based panels intended for load-bearing timber structures.

FAQ

Q: What is BS EN 789?

BS EN 789 is a European standard specifying test methods for determining mechanical properties of commercial wood-based panels intended for use in load-bearing timber structures. These include bending, tension, compression and shear properties.

Q: What does the bend test measure?

Bend testing can be used to determine properties including bending strength and modulus of elasticity in bending. The test provides information about both the strength and stiffness of a wood-based panel when subjected to flexural loading.

Q: What materials can be tested to BS EN 789?

The standard applies to commercial wood-based panel products intended for load-bearing structural applications. Relevant products can include plywood, OSB, LVL and other structural wood-based panels.

Q: Is BS EN 789 intended for routine quality control?

No. BS EN 789 is intended to establish mechanical properties for the determination of characteristic values for structural use and is not intended as a routine quality control test.

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