Rocking revisited 4: Analysis of rocking-induced stresses for concrete breakwater armour units

When a breakwater is under heavy wave attack, the concrete armour units will occasionally move, causing a collision between two concrete armour units. This process is called rocking, and induces stresses in the concrete, that may lead to breakage of the concrete armour units. This MSc Thesis provides a probabilistic method to predict breakage of...

Granular open filter in rubble mound sand retaining structures: Physical model tests of a negative geometrically open filter layer

For the use of open filters in land reclamations new guidelines are needed as no research is currently done for the configuration of a sand layer is placed on top of a filter layer. This research focuses purely on the interaction between cyclic motions and the described sand-filter layer. A numerical OpenFOAM model is used to extract the order...

A parametric approach to a probabilistic design of rubble mound slope protection

When designing hydraulic structures, engineers follow a structured and predetermined set of design phases, referred to as the design process. Within this process, the preliminary design phase is a highly iterative process, which requires many calculations. From these calculations many different initial designs of the structure are derived....

Tolerable wave overtopping during construction of a breakwater

Wave overtopping is an important aspect for the design of rubble mound breakwaters. Acceptable overtopping limits are usually based on the mean overtopping discharge or the maximum overtopping volume (EurOtop, 2018). For temporary situations, such as breakwaters under construction, overtopping limits are not clearly defined. This complicates the...

Simulating wave penetration in an inlet using the numerical models SWAN and SWASH: Dimensioning of an inlet and the comparison of two numerical models

Near IJburg a new Island named Strandeiland is being build to create living area. On the eastern part of this island an inlet is situated. In this research the wave penetration in this inlet is simulated using the numerical models SWAN and SWASH. With the results of the simulations the verticall walls which surround the inlet are dimensioned....

Rocking of single layer armour units: Rocking revisited 3

After the failure of several large breakwaters in late 1970’s and early 1980’s where the role of rocking and breakage of armour became apparent, the importance of understanding this rocking phenomenon is given a great emphasis. Single layer randomly placed armour units are widely used in breakwater designs as they are more economical due to the...

Investigation of crown wall stability on top of rubble mound structures with OpenFOAM®

In the present study the stability of crown wall elements on top of a rubble mound breakwaters is investigated. The first step was conducting a literature review, in order to identify knowledge gaps. It was found that current design methods do not take the freeboard of the crown wall into account when calculating the vertical force acting on it....

Prediction of the characteristics of a tsunami wave near the Tohoku coastline: Numerical SWASH modelling

To calculate tsunami forces on coastal structures, the wave type in front of the coast is of great importance. Hence this paper aims to find ways to predict the type of tsunami wave breaking. Based on literature review, video footage, analytical reasoning and numerical modelling (SWASH) it can be concluded that both the continental shelf slope ...

Wave damping potential of woody riparian vegetation: Comparing terrestrial laser scanning with manual measuring techniques

Including vegetation in flood defense systems has the potential to be a more cost-effective solution than conventional dike reinforcement measures, as vegetation contains wave damping properties. However, more insight is required on the complex physical processes due to wave-vegetation interaction in order to predict the amount of wave damping....

A Deterministic Method To Detect Wave Directions From Surface Elevations: Accuracy And Sensitivity Analysis For The SWDD Method By Using Synthetic Wave Signals And The Mild-Slope Wave Model WIHA

This research describes a new method called SWDD (Klopman, Witteveen+Bos, 2018b), which can obtain information on wave propagation directions from the surface elevations at a set of positions. The primary intention of the method is to separate multiple incoming wave components, i.e. wave heights, phases and directions. The goal is to obtain the...

Stability of rock-based emergency measures based on the Grave Weir calamity

On the 29th of December 2016 a large Rhine ship loaded with 2000 ton benzene sailed through the weir at Grave, located in the river Meuse in the Netherlands. The accident created a large gap in the weir and within 12 hours the upstream water level decreased by a maximum of 3 meters. Due to this decreased water level shipping was limited,...

2D modelling of initiation of failure of a clay slope under wave overtopping load

A growing risk of flooding in coastal areas and the corresponding development of legislation drive continuous development in the field of hydraulic engineering. Failure due to<br/>wave overtopping is not fully understood from a physical point of view. Existing knowledge gaps, processes that are not yet explained by physics or not even discovered...

Stability analysis of XblocPlus crest element

In the past humans used to protect their shores mainly with rocks. In the past decades the shore protections did gently shift to concrete element protections. An example of an often applied concrete armour unit is the Xbloc. This element is quite strong and well investigated. BAM Infraconsult has developed a uniformly placed armor unit, the...

The prediction of stone stability by a three-dimensional eddy resolving simulation technique

In this thesis, it is studied if the stability of a stone in a granular bed protection, can be predicted by the local output of a three-dimensional (3D) eddy resolving simulation technique.<br/><br/>In earlier studies regarding stone stability, Reynolds-Averaged Navier-Stokes (RANS) models are used to determine the loads on the bed. In the...

Wave loads on vertical walls: Validation of design methods for non-breaking waves of bimodal spectra

During the design process of the new sea lock in IJmuiden the design wave conditions were described by a bimodal wave spectrum. With a spectral calculation method it was observed that a small low frequency component leaded to a large influence in the force spectrum. This observation served as the starting point for this thesis, where different...

Physical modelling of reflection on gentle coasts: Comparing methods to analyse long waves and optimising the lay-out for a wave absorber to minimise reflection in a wave flume

Studying mangroves in the field can be very difficult; therefore it is in some situations better to model in a flume. The question is, to what extend are the situation in the field and the situation in the flume comparable with each other? This study focusses on reflection in the wave flume. Wave energy in a flume can be damped by placing a wave...

Characterization of incoming tsunamis for the design of coastal structures: A numerical study using the SWASH model

The Tohoku Tsunami of 2011 in Japan flooded a large part of the coastal area of Japan. The tsunami was caused by an earthquake with a magnitude of 9.0 just of the coast of Tohoku. The inundation height of the tsunami exceeded the design height of the tsunami barriers. This event led to thousands of fatalities. <br/>The aim of this study is to...