Sheet Piling has, for many years, been adopted as the primary solution when constructing quay walls and berthing facilities in a marine environment. As the requirements of port operations have developed over time, with larger and deeper berths being constructed to accommodate larger vessels, so has the design and range of steel and sheet pile elements been developed to provide greater design capacity. In addition to the ongoing developments in the basic materials available, particularly in the UK and Europe, significant changes are being made to design methodology with the introduction of the Eurocodes. These are a suite of standards which are being adopted across Europe and will replace many national standards currently used for the design and construction of sheet pile walls. The Eurocodes consist of standards covering the basic materials used in construction and the design methods to be adopted, and are accompanied by a number of execution codes which detail how the construction should be undertaken.
A summary of the Eurocode standards is given below:
EN 1990 Eurocode: Basis of structural design
EN 1991 Eurocode: Actions on structures
EN 1992 Eurocode: Design of concrete structures
EN 1993 Eurocode: Design of steel structures
EN 1994 Eurocode: Design of composite steel and concrete structures
EN 1995 Eurocode: Design of timber structures
EN 1996 Eurocode: Design of masonry structures
EN 1997 Eurocode: Geotechnical design
EN 1998 Eurocode: Design of structures for earthquake resistance
EN 1999 Eurocode: Design of aluminium and aluminium alloy structures
For steel sheet piling, the most significant elements of the Eurocodes are:
EN 1990 Eurocode: Basis of structural design
EN 1993 -5 Eurocode: Design of steel structures – Piling
EN 1997 -1 Eurocode: geotechnical design – General rule
Plus the accompanying execution code:
EN 12063 Execution of special geotechnical work – Sheet pile walls
The impact of the Eurocodes has also driven significant revision in the suite of British Standards covered by BS6349 – Maritime Works, which have been used for many years on an international basis.
Standards and Codes of Practise
The current BS6349 standards are not based upon the use of ‘limit state design’, and as this approach is the fundamental basis of the Eurocodes, significant changes to the design sections have been required to bring them in line with the European standards. Whilst this in itself should not have a significant effect upon the overall use of sheet piles within ports and harbours, there are a number of issues which can arise if the new codes are not fully understood and applied correctly. Examples of potential pitfalls or areas of uncertainty include:
Language – The Eurocodes have been produced on the basis of agreeing a consistent use of language to describe elements of the design process. For example, the Eurocodes aim to use the term ‘Action’ instead of ‘Forces’ or ‘Loads’ acting on structures. However, on closer examination of the documents, references can be found to ‘Loads’. It appears that an ‘Action’ can be a ‘Load’ when it has its own mass!
