Mar 2013
Electricity Transmission
Phase III Centrifuge Modelling and Field Monitoring of Wind Induced Loads on Transmission Towers
Mar 2013
National Grid Electricity System Operator
National Grid TO Innovation Team
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Innovation Funding Incentive
Gas Distribution Networks
The outsourcing of all National Grid Tower design activities for OHL refurbishment using Pre-Sanction Engineering (PSE) has highlighted a difference in approach taken by National Grid and its contractors to assess the capacity of existing structures and foundations. Contractors use the current design code BS EN 50341 (normally intended for new build). The contractors analyses have indicated that tower foundations have a substantially lower capacity to resist uplift forces than previously assumed.

To date, foundation strengthening work identified by PSE has been put on hold pending further R&D by National Grid. These issues have been partially addressed by recent R&D work ref NSETH118. This previous work has successfully established a method of testing 1:50 scale foundation models in centrifuge apparatus capable of giving full scale results.

The project has defined the following benefits:

  • To carry out enhanced environmental modelling of full Overhead Line (OHL) support system fully instrumenting a short section of line

  • To carry out centrifuge modelling to expand the range of foundation and soil types currently considered, using the data collected by the environmental modelling

  • To assess the appropriateness of current British Standard method for determining tower foundation uplift capacity and influence the change of industry design codes.