Timber Member Design to Eurocode 5 (EN 1995-1-1)

## About this Timber Member Design to Eurocode 5 Calculator This calculation checks a rectangular timber member to Eurocode 5 (EN 1995-1-1), covering the design strengths, cross-section checks and stability. It works the modification factor for load duration and moisture, the size effect, and every applicable limit state, returning a governing utilisation with a pass or fail. Solid timber and glulam strength classes are supported. Every step is worked in visible maths. - **Timber and structural engineers** enter the section, strength class and design actions and read the governing check straight away. - **Design reviewers and checkers** trace each clause and factor against EN 1995-1-1. - **Graduates and students** see how load duration, moisture and the size effect change the design strengths. It is an engineering-grade calculation on CalcTree that you can duplicate, edit and fold into your own project workspace. ## More info on Timber Member Design to Eurocode 5 ### Inputs Enter the section and length, pick the strength class, service class and load-duration class, and set the lateral restraint and design actions including the perpendicular-to-grain bearing force. Characteristic strengths are read from the strength-class tables. ### Design checks The calculation covers bending, shear, tension, compression parallel to grain, bearing perpendicular to grain, combined bending and axial force, column buckling and lateral-torsional buckling. The governing utilisation is the largest across all checks. ### Methods Design strengths apply the modification factor and the material partial factor per EN 1995-1-1, with the size effect on bending and tension. Stability uses the buckling and lateral-torsional reduction factors. The maths is carried in MathJS, with a single chart summarising the utilisations. ## Common Calculation Errors to Avoid - **Wrong modification factor** the load-duration and service-class combination sets the strength modification and every strength check. - **Class and factor mismatch** solid timber and glulam use different partial and imperfection factors. - **Size effect omitted** small sections gain strength in bending and tension through the size factor. - **Missed lateral-torsional buckling** an unrestrained compression edge reduces the bending capacity. - **Bearing overlooked** compression perpendicular to grain governs at supports and point loads.

## FAQs ### What is the modification factor and why does it matter? The modification factor scales the design strengths for load duration and service (moisture) class. A short-duration action in a dry service class gives a higher design strength than a permanent action in a wet one, so it directly changes every strength check. ### Does this handle both solid timber and glulam? Yes. Strength classes for solid timber (EN 338) and glulam (EN 14080) are selectable, and the correct partial factor and imperfection factor follow from the choice. ### What is the size effect? Smaller sections show higher apparent strength in bending and tension, captured by a size-effect factor applied to those checks. ### How is stability checked? Column buckling reduces the compression capacity, and lateral-torsional buckling reduces the bending capacity when the compression edge is unrestrained. Both feed the governing utilisation. ### Can I check bearing at supports? Yes. Compression perpendicular to grain is checked against the bearing force and length at the support.