Plastic bending of steel sheet piles

Plastic bending of steel sheet piles will be allowed when Eurocode 3 Part 5 comes into force. Previously, steel sheet piles have been designed so as to remain within the elastic range of behaviour, and therefore there is no experience of the impact of plastic hinging on the response of retaining walls. Investigations have previously been undertaken in order to define the plastic section characteristics of steel sheet piles, and Eurocode 3 Part 5 incorporates the outcome of these studies, categorising sections that are suitable for plastic design. Guidance as to how plastic rotation demand can be verified in the absence of calculations that provide this implicitly is also provided. Subsequent investigations have suggested that there are some limitations to the approach outlined in the Eurocode, and that in some cases the use of these methods may not be safe. This paper outlines the basis for these latter investigations, and provides recommendations on how plastic design of steel sheet pile walls can be safely implemented.