Permanent Sheet Pile Retaining Walls

Sheet Piling (UK) Ltd are a leading specialist in the use of steel sheet piles to form permanent sheet pile retaining walls on a wide variety of schemes and applications.

Commonly steel sheet piles are specified and installed as the permanent retaining structure on schemes where insufficient space is available for complex temporary works which would otherwise be required to allow construction of alternative retaining solutions; or where the cost and programme benefits of permanent sheet piling dictates this to be the optimum retaining solution.

On road and rail infrastructure projects, the sheet piles are designed to relevant Highways Agency or Network Rail design standards together with associated design and checking certification. Typically these specifications require a design life of 120 years together with surcharge loading relevant to the proposed application (i.e. Highway HB loading or Railway RU loading).

Other common applications include retail and commercial service yards, flood defence walls, axially loaded bridge abutments and boundary retaining walls for residential developments.

Sheet Piling (UK) Ltd’s experienced in-house design engineers are able to offer a full design service for such schemes, including the relevant Approval in Principal or Form B documentation, together with independent checking (where applicable).

An alternative to a traditional sheet pile retaining wall is a King Sheet Piling (KSP) retaining wall which utilises pairs of Z section piles as ‘Kings’ with lighter and shorter Z piles as ‘intermediates’ spanning horizontally between them.

On certain projects the use of KSP retaining walls can provide steel savings over a traditional retaining wall solution along with some environmental and constructibility benefits. However the designers of a KSP wall need to consider the reduced stiffness which can have a significant impact on wall deflections.

Permanent sheet pile retaining walls are generally designed using Z Section Sheet Piles which utilise the benefit of the high-strength to low weight ratio of such sections. Typically, Z section sheet piles will be supplied by Arcelor Mittal or Emirates Steel since both steel manufacturers have BES6001 Responsible Sourcing of Construction Products which is mandatory on public sector projects.

Once installed, sheet piles have an immediate and structural capacity allowing excavation to commence immediately and no spoil is generated as is the case for alternative secant and contiguous pile walls. If required the exposed sheet piles can then be shot blasted and painted to provide an aesthetically acceptable finish and enhance the pile section design life. Alternatively a wide range of ‘non structural’ cladding solutions can be constructed in front of the wall.

In addition a reinforced concrete capping beam can be cast to the top of the permanent sheet pile retaining walls to which any containment barriers / hand railing can be directly fixed. Alternatively a steelwork capping beam can be specified.

Finally to prevent build up of excessive hydrostatic water pressures behind the sheet pile wall, drainage weep holes are formed nominally above the final excavation level. On critical applications where preventing loss of fines through the weep holes whilst ensuring any hydrostatic pressures are relieved, consideration should be given to the use of the unique ‘Blue Marlin Weep Hole Filter System‘.

Some recent successfully completed permanent sheet pile retaining wall projects are listed below: