Wolf Rock lighthouse

Past developments and future survivability under wave loading

Journal Article (2019)
Author(s)

A. C. Raby (Plymouth University)

A. Antonini (TU Delft - Coastal Engineering)

A. Pappas (University College London)

D. T. Dassanayake (Plymouth University)

J. M.W. Brownjohn (University of Exeter)

D. D'Ayala (University College London)

Research Group
Coastal Engineering
DOI related publication
https://doi.org/10.1098/rsta.2019.0027
More Info
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Publication Year
2019
Language
English
Research Group
Coastal Engineering
Issue number
2155
Volume number
377
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Abstract

Lighthouses situated on exposed rocky outcrops warn mariners of the dangers that lurk beneath the waves. They were first constructed when approaches to wave loading and structural response were relatively unsophisticated, essentially learning from previous failures. Here, we chart the evolution of lighthouses on the Wolf Rock, situated between Land's End and the Isles of Scilly in the UK. The first empirical approaches are described, followed by design aspects of the present tower, informed by innovations developed on other rocky outcrops. We focus on a particular development associated with the automation of lighthouses: the helideck platform. The design concept is described and the structure then scrutinized for future survivability, using the latest structural modelling techniques of the entire lighthouse and helideck. Model validation data were obtained through a complex logistical field operation and experimental modal analysis. Extreme wave loading for the model required the identification of the 250-year return period wave using a Bayesian method with informative prior distributions, for two different scenarios (2017 and 2067). The structural models predict responses of the helideck to wave loading which is characterized by differential displacements of 0.093m (2017) and 0.115m (2067) with associated high tension forces and plastic strain.