Case Study: Temporary Sheet Pile Cofferdam for Water Storage Tank

Temporary Sheet Pile Cofferdam for Water Storage Tank

Contract No:C1290
Client:Morgan Sindall Construction and Infrastructure Ltd
Location:Northumberland Avenue, Llanelli
Value:Approx. £120,000.00
Summary:Design, Supply, Installation and Extraction of a Temporary Sheet Pile Cofferdam and Associated Temporary Steel Work Bracing to Facilitate Construction of an Underground Water Storage Tank

Sheet Piling Contractors, Sheet Piling (UK) Ltd. Were appointed by Morgan Sindall Construction & Infrastructure Ltd for the design, supply, installation and extraction of temporary sheet piles and an upper steelwork bracing to form a cofferdam to facilitate construction of a cast in-situ Concrete Water Storage Tank.

Working closely with Morgan Sindall Construction & Infrastructure Ltd throughout the design development stages, Sheet Piling (UK) Ltd provided a temporary sheet pile design solution which satisfied all the project criteria for the works.

The Overall Cofferdam Dimensions were approximately 33.0m x 24.0m and the maximum excavation depth was 6.15m Locally Increasing to 6.895m.

The temporary sheet pile cofferdam was constructed using 190No. 10.0m/11.0m Long Arcelor GU18N temporary sheet piles and approx. 30Te of temporary steelwork for the Upper Steelwork Bracing Frame. In addition, a proprietary hydraulic modular lower bracing frame was designed and installed by others to withstand frame loadings supplied by Sheet Piling (UK) Ltd.

In order to install the temporary sheet piles a tracked Telescopic Leader Rig was utilised along with its attached High Frequency Vibratory Hammer in association with a 50Te Mobile Crane acting as a service crane.

The general soil profile consisted of Made Ground over a band of Clay and Peat over a medium dense to dense Gravels over mudstone, which made installation using a Leader Rig c/w Vibratory Hammer the most economical and viable installation and extraction method for the sheet piles.

The installation works was completed during a 2No. week period in April 2018 and extraction of the sheet piles was carried out in January 2019 to the satisfaction of all parties.

Steel Sheet Piles Craned into Position
Steel Sheet Piling