With 95 per cent of the UK’s international trade transported by sea, rock-mounted lighthouses have a crucial role to play in safe navigation – but the longevity of these historical structures is threatened by extreme weather.
So, the Vibration Engineering Section (VES) have teamed up with researchers at Plymouth University and University College London to start a project assessing six of the most vulnerable lighthouses in the UK and Ireland.
VES Experimental Officer James Bassitt joined Julian Seipp, Senior Technician at Plymouth University on Longships Lighthouse at St Just near Lands End, to begin STructural behaviour Of Rock Mounted Lighthouses At the Mercy of imPulsive waves (STORMLAMP). An EPSRC funded project, STORMLAMP will combine field, laboratory and mathematical/computer modelling methods.
James and Julian were given access to the lighthouse by General Lighthouse Authority, Trinity House and were flown there by helicopter, along with a maintenance crew. There, they retrieved data gathering geophones previously installed on the lighthouse by the University of Plymouth as part of a pilot project leading into STORMLAMP, and replaced them with triaxial accelerometer data logging equipment. In addition, they carried out a full survey of the lighthouse to help them to come up with a long term monitoring solution and testing plan.
James Bassitt said: “I would like to thank Trinity House, including Ian Gorvin and Malcolm Johns for their support on the day and for their help with future planning. We have taken the geophones back to Exeter to benchmark them against highly sensitive accelerometer data logging equipment.
He added: “The next stage will be to carry out a data gathering exercise at a lighthouse off the coast of Guernsey in June.”
As part of STORMLAMP, field instrumentation and procedures will be developed by the University of Exeter (James Brownjohn and James Bassitt) for the highly challenging constraints. Meanwhile, UCL (Dina D’Ayala will create test data guiding of multi-scale numerical simulations for lighthouses that can be used with the full-scale data to diagnose observed performance in the long term monitoring.
These models will link with advanced physical and CFD simulations by Plymouth University’s COAST Laboratory (Alison Raby-who leads the project- and Deborah Greaves).
STORMLAMP will move to a focus of one lighthouse for the following two winters. Based on these modelling exercises, the long term monitoring of a single structure will used to characterise the wave loading in-situ at full scale. The project will support performance management of such structures worldwide.