Concrete @ your Fingertips

Design working life

BS EN 1990, Eurocode - Basis of structural design, (Eurocode 0) gives indicative design working lives (in Table 2.1) for design purposes for various types of structures, as follows:

Category 1 – Temporary structures, not including structures or parts of structures that can be dismantled with a view to being re-used – 10 years
Category 2 – Replaceable structural parts, e.g. gantry girders, bearings – 10 to 25 years
Category 3 – Agricultural and similar buildings – 15 to 30 years
Category 4 – Building structures and other common structures – 50 years
Category 5 – Monumental building structures, bridges and other civil engineering structures – 100 years

It should be noted that the UK National Annex to BS EN 1990:2002 gives modified indicative design working lives for some of the Categories as follows:

Category 2 – 10 to 30 years
Category 3 – 15 to 25 years
Category 5 – 120 years

These Categories do not align with the 2023 update to BS EN 1990. Importantly Category 5 which is still used by National Highways, and other UK guidance. This was covered in IAN 95/07, although this has now been withdrawn. For concrete durability, BS 8500-1 Concrete is used which is based on at least 50 or 100 years intended working life and this is covered in the Manual of Contract Documents for Highway Works (MCHW), Vol. 1, Specification for Highway Works, Series 1700.

Prior to the introduction of the Eurocode a design life of 60 years was required for buildings, although this period was never included in any of the structural design Codes. For concrete bridges it had always been up to 120 year design life.