KNOWLEDGE BASE

How long do gabions last

How long do gabions last?

The quick answer to the question ‘how long do gabions last?’ is between 20 and 120 years depending on the wire specification and environment of the installation.

The longer answer is as follows :

It depends on what your customer means by the ‘life span’ of the gabions.

The ‘design life’ of a gabion structure (as defined in BS EN 10223-8 annex A and with regard to different wire coating and environmental/corrosive categories where installed) is subject to the appropriate design of the structure, proper installation, use, periodic inspection & repair/maintenance as needed, to achieve the actual working life, rather than being a measure of the longevity or durability of the gabion mesh when taken in isolation.

Design working life v actual working life

The notes which follow Table A.1 in BS EN 10223-8 states the following;

‘A clear distinction has to be made between the assumed economically reasonable working life for a product (also called: design working life), which underlies the assessment of durability in Technical Specifications, and the actual working life of a product in a works. The latter depends on many factors beyond the control of the producer, such as design, location of use (exposure), installation, use and maintenance.

The assumed working life can thus not be interpreted as being a guarantee given by the producer.

Technical Specification writers will have to take a view about the “normal” working life of the products that they deal with. The assumed working life of a product should take account of the assumed working life of the works, the ease and cost of repair or replacement of the product, maintenance requirements and exposure conditions.’

As detailed above, it shouldn’t be assumed that the gabion units or welded mesh will achieve a working life of 120 years on their own, as this definition also takes into account the design of the structure, quality of installation, ongoing maintenance & repair, exposure and other similar external factors which are outside the control or remit of the manufacturer.

As such, the assumed working life of 120 years or greater refers to the structure as a whole, and cannot be borne by a single component of that structure (i.e. the welded mesh). Our gabion baskets can certainly perform as part of a structure which has been designed & installed with the intent of a 120 year design life, providing a proper inspection/maintenance/repair schedule is followed throughout that period.

If your customer is expecting the welded wire mesh to last for 100+ years, irrespective of everything mentioned above, then the only option would be to go for stainless steel (grade 316) welded mesh, made from a heavy gauge wire (i.e. 5mm dia.). This would be the most long-lasting specification for the wire itself (with regards to resisting corrosion and physical damage to the wire), but the mesh would still be vulnerable to mechanical damage (whether accidental or deliberate), as well as the potential effects of poor design and/or installation.

Ultimately, the answer as to what to offer and how to answer their question will come down to the project specification.

Paul Richardson

B.Eng (Civil Engineering)

Design Engineer & Technical Sales

Dunstall Park Trading Estate, Wolverhampton, WV6 0PJ.

Gabion Sales: +44 (0)1902 712200 (opt. 3) | DDI: 01902 973739

www.hy-tengabions.co.uk