Hydrodynamic Load on the Building Caused by Overtopping Waves

Abstract

Wide crested dike can reduce the kinetic energy of the overtopping wave and make the overtopping wave to flow back to the seaside. If a coastal town were built on or near a dike, the overtopping wave running on the dike crest generates the force which can affect the buildings located in its path. However, quantifying the hydrodynamic load on the building caused by overtopping waves is not straightforward because little empirical formulas are given in literature for this kind of configuration. Therefore, physical scale model research was carried out. The purpose of this research is to come up with a relationship describing the force on a vertical wall exerted by the overtopping wave as a function of wave parameters and geometrical characteristics.

Prediction of Dynamic and Quasi-Static Impacts on Vertical Sea Walls Caused by an Overtopped Bore

“…Based on these findings it was stated that only a 80% of the maximum run-up Rh,max was effectively contributing to the impact force on the wall. Substituting Equation 12into Equation 11 yields in a coefficient of 0.32, which was very close to what was found earlier as C1 = 0.30 by adapting the momentum flux theory and using regular waves (Chen et al, 2012). Hence, this finding served as a largescale confirmation that the prediction of quasi-static force peaks F2 using 80% of the maximum run-up height was also valid for irregular waves.…”

“…Based on these findings 80% of the maximum run-up height was effectively contributing to the maximum quasi-static force F2 on the wall. The results coincided well with previous small-scale studies (Chen et al 2012). After deconstructing the process chain preceding an impact, using the physically most meaningful parameters to predict the impact force, evaluating on a range of existing approaches, and observing the scattered prediction results, it was concluded that the impact behavior is highly stochastic and statistical analysis would be more beneficial.…”

“…A number of studies were conducted on similar geometries (mild foreshore, dike) to the geometrical setup of the present study using short duration (~0.5 -3 s) overtopped wave impacts. They were divided into studies which derived an individual force F ( Van Doorslaer et al 2016, Chen et al 2012 or an averaged force such as F1/250 based on averaged test parameters (Van Doorslaer et al 2016, Chen et al 2015, Kortenhaus et al 2015, Verwaest et al 2011, Allsop 2005, Kleidon 2004, Den Heijer et al 1998.…”

“…Hence, only formulae predicting an individual bore impact force were further investigated. For regular waves and a variable wall location, a study was conducted in a small-scale experimental set-up (Chen et al 2012). Based on momentum flux theory they were able to predict the second force peak solely dependent on the maximum run-up height Rh of the water at the wall.…”

Overtopping Flow Impact on a Vertical Wall on a Dike Crest

“…Therefore, it is important for designers and owners to recognize the key hazards (e.g., building damage) from the overtopping flow. Chen et al (2012 and Ramachandran et al (2012) reported their laboratory work of overtopping flow loads on vertical structures on a dike crest by physical models at different scales. Common findings of these works suggested that the observed force evolution shape of overtopping flow has a double-peak, which is similar to the "church-roof" time history of wave breaking impact force proposed by Oumeraci et al (1993) for deeper water wave impacts on caissons and composite structures.…”