West Coast Main Line Overhead Electrical Structures
Contract Details.
Client: WS Atkins Consultants
Background.
As part of the up-grading of the West Coast Route, new overhead line electrification (OLE) structures were installed to replace life-expired existing structures and to limit the wire deflection at exposed locations under high winds by reducing the spans between structures. Over 1000no new OLE structures were proposed, the majority of which are located on high embankments in North West England and the South of Scotland.
Contract Details.
Client: WS Atkins Consultants
Background.
As part of the up-grading of the West Coast Route, new overhead line electrification (OLE) structures were installed to replace life-expired existing structures and to limit the wire deflection at exposed locations under high winds by reducing the spans between structures. Over 1000no new OLE structures were proposed, the majority of which are located on high embankments in North West England and the South of Scotland.
Raison Foster Associates Brief.
Raison Foster Associates worked as a sub-consultant to WS Atkins Consultants as part of the design team to project manage and co-ordinate of the embankment risk assessment and OLE structure foundation design programme for W S Atkins. The embankment stability issues were investigated. Research identified that there was little experience of installing driven steel cased piles on marginally stable embankments.
A procedure for geotechnical decision-making was proposed by the design team based on the information obtained from the embankment inspections by W.S. Atkins' geotechnical engineers.
A risk assessment system using the findings of the desk study, field survey and on-site inspection was developed in order to rank the proposed structure locations. This enabled the highest risk locations to be identified and examined in further detail.
This approach enabled driven piling to proceed at most of the structures, reducing the delay which had become a project risk. At high risk locations, survey and ground investigation works were instructed to give a detailed assessment of embankment stability. Following this, alternative foundation design proposals based on non-percussive and non-displacement piles were developed.
Monitoring of embankment locations during construction has confirmed the success of the procedure in managing the geotechnical risk
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