Implications of second-order wave generation for physical modelling of force and run-up on a vertical wall using wave groups

Experiments are contaminated by second-order error waves at sub- and super-harmonic frequencies when first-order wave generation is used. Herein, we investigate by experiment the implications of second-order wave generation theory for dynamic wave force and run-up on a vertical wall in shallow to intermediate water depth (k₀d=0.5−1...

Correct generation of the bound set-down for surface gravity wave groups in laboratory experiments of intermediate to shallow depth

Using linear (first-order) wave generation theory in laboratory experiments, leads to significant contamination of the wave field by free non-linear (second-order) error waves, increasingly so at shallower depths. Second-order wave generation theory has previously been established, and so has correct generation of the bound set-down, made up...

Influence of the Spatial Pressure Distribution of Breaking Wave Loading on the Dynamic Response of Wolf Rock Lighthouse

The survivability analysis of offshore rock lighthouses requires several assumptions of the pressure distribution due to the breaking wave loading (Raby et al. (2019), Antonini et al. (2019). Due to the peculiar bathymetries and topographies of rock pinnacles, there is no dedicated formula to properly quantify the loads induced by the breaking...

Rocking of offshore lighthouses under extreme wave impacts: Limit analysis, analytic formulations and distinct element method

This study describes the structural response of historic lighthouses to extreme wave impacts. Located offshore on exposed rocks, 19th Century lighthouses were built with large interlocked granite blocks and have survived weathering for nearly two centuries. Under extreme wave impacts, lighthouses of this structural typology may uplift and...

A Bayesian inverse dynamic approach for impulsive wave loading reconstruction: Theory, laboratory and field application

The measurement of wave forces acting on marine structures is a complicated task, both during physical experiments and, even more so, in the field. Force transducers adopted in laboratory experiments require a minimum level of structural movement, thus violating the main assumption of fully rigid structure and introducing a dynamic response...

Bayesian oma of offshore rock lighthouses: Surprises with close modes, symmetry and alignment

A set of seven rock lighthouses around the British Isles was studied by a combination of forced and ambient vibration tests executed with some extreme logistical constraints. Forced vibration testing of the circular section masonry towers combined with experimental modal analysis identified modes with alignment assumed the same as the shaker...

Efficacy of analysis techniques in assessing broken wave loading on a cylinder upon a shoal

Estimation of impulsive wave loading on a cylinder upon a shoal, such as an offshore rock lighthouse constructed on a partially emerged offshore rock with a steep foreshore, poses a unique challenge to marine structural engineers. Large and small scale experimental investigations are the most feasible methods to study this phenomena. However,...

Survivability assessment of fastnet lighthouse

Historic rock lighthouses are unusual structures that are situated in hostile marine environments to provide warning to mariners. Even in an era of satellite navigation their role continues to be an important one, but their survivability into the future is not assured. Out of concern for their ongoing service, the multidisciplinary STORMLAMP...

Environmental loading of heritage structures

This theme issue, featuring Environmental loading of heritage structures, provides a snapshot of current civil engineering approaches to assessing ageing structures under a variety of loads. The publication arose from a serendipitous sequence of interactions. Academics at the University of Plymouth were contacted by Trinity House in 2010 to...

Bayesian operational modal analysis of offshore rock lighthouses: Close modes, alignment, symmetry and uncertainty

Despite use of GPS, lighthouses remain critical infrastructure for preserving safety of mariners and maritime trade, and the most dramatic examples are probably the Victorian era masonry towers located on remote offshore reefs around the British Isles and exposed to extreme weather conditions. Due to their age and likely increasing future...