Design and construction of mound breakwaters

Se describe la evolución de las técnicas de diseño de los diques rompeolas y de algunos equipos y técnicas constructivas que los han impulsado. Se analiza sobre todo la influencia de las investigaciones teóricas y de laboratorio, desde los estudios y procedimientos pioneros de Iribarren hace 80 años hasta la construcción de diques protegidos con mantos monocapa de las últimas décadas y la optimización económica de las huellas energéticas y del carbono para una construcción sostenible. Se analiza el desarrollo de nuevos conceptos, la invención de nuevas formas geométricas para las unidades del manto, el gran impacto de las observaciones basadas en los ensayos físicos a escala reducida y la importancia de los condicionantes logísticos, métodos y técnicas de cada época para explicar la evolución en la manera de diseñar y construir grandes diques en talud a lo largo del tiempo.Se agradece la financiación proporcionada por el Ministerio de Economía y Competitividad y FEDER (BIA2012-33967)

Experimental comparison to test the eligibility of the wave parameters H50t and H50i in the stability formulation for overtopped breakwaters

RESUMEN: Se ha realizado una investigación mediante modelación física sobre diques en escollera rebasables con el objetivo de verificar la idoneidad del uso de los parámetros de altura de ola H50t (altura promedio de las 50 mayores olas totales) y H50i (altura promedio de las 50 mayores olas incidentes) en la formulación de los números de estabilidad que permiten diseñar la estructura. Adicionalmente, se ha introducido la dependencia del francobordo en estas formulaciones. Se han realizado ensayos experimentales sobre una estructura en escollera con un núcleo y un manto bicapa, para tres niveles de francobordo (emergido, a nivel del agua en reposo y sumergido), a escala 1:50. Se han comparado los valores del daño S medidos y calculados, considerando las estimaciones obtenidas en función de la altura de ola incidente H50i y de la altura total H50t. Se ha demostrado que, para la estructura utilizada en este trabajo, el mejor ajuste se obtiene utilizando la H50i en la estimación del daño. Una posible razón de la peor estimación del daño utilizando la altura de ola total es que la necesidad del uso de una fórmula para el coeficiente de reflexión R añade una nueva dispersión a los resultados.ABSTRACT: An investigation on low-crested breakwater has been carried out using physical modeling with the objective of verifying the suitability of using the wave parameters H50t (average height of the 50 largest total waves) and H50i (average height of the 50 largest incident waves) in the stability formulations. Additionally, the dependence of the freeboard has been introduced in the mentioned formulations. Experimental tests have been performed on a breakwater structure with a core and a two-layer armour, for three freeboard levels (emerged, at still water level and submerged) at 1:50 scale. The measured and calculated damage values, S, have been compared, considering the different estimations based on the incident wave parameter H50i and the total wave parameter H50t. It has been shown that for the structure used in this work, the best fit was obtained using the parameter H50i. One possible reason for that is the fact that in the estimation of H50t the need to use a formula for the reflection coefficient R adds new dispersion results

Analysis of the Pressures in the Crown-Wall of Rubble-Mound Breakwaters under Tsunami Actions, Based on Laboratory Experiments

The research leading to these results has received funding from the European Union's Seventh Framework Programme (FP7/2007-2013) under grant agreement n° 603839 (Project ASTARTE - Assessment, Strategy and Risk Reduction for Tsunamis in Europe)

Estructura flotante e instalación para el aprovechamiento de la energía del oleaje utilizando un catamarán flotante con varias cámaras de columna de agua oscilante.

Una estructura flotante para el aprovechamiento de la energía del oleaje, que comprende múltiples cámaras independientes de columna de agua oscilante (CAO) alineadas, abiertas por el fondo, estando cada cámara comunicada por la parte superior con la atmósfera a través de un grupo turbo-generador formado por un conducto de aire, en cuyo interior se ubican una válvula de control del flujo de aire y una turbina de aire auto-rectificadora conectada a un alternador.Solicitud: 201100242 (28.02.2011)Nº Pub. de Solicitud: ES2387492A1 (24.09.2012)Nº de Patente: ES2387492B2 (26.03.2013

Simulation of Marine Towing Cable Dynamics Using a Finite Elements Method

A numerical model to study the towing maneuver for floating and submerged bodies has been developed. The proposed model is based on the dynamic study of a catenary line moving between two bodies, one body with imposed motion, and the other free to move. The model improves previous models used to study the behavior of mooring systems based on a finite element method by reducing the noise of the numerical results considering the Rayleigh springs model for the tension of the line. The code was successfully validated using experimental results for experimental data from different authors and experiments found in the literature. Sensitivity analysis on the internal damping coefficient and the number of elements has been included in the present work, showing the importance of the internal damping coefficient. As an example of the application of the developed tool, simulations of towing systems on a real scale were analyzed for different setups. The variation of the loads at the towed body and the position of the body were analyzed for the studied configurations. The reasonable results allow us to say that the proposed model is a useful tool with several applications to towing system design, study or optimizationThe authors are grateful to the Spanish Ministry of Economy, Industry and Competitiveness for funding ACOPLE- Analysis of the dynamic behavior of floating wind platforms for design optimization in deep waters (ENE2017-89716-R), within the National Programme for Research, Development and Innovation Aimed at the Challenges of Society (Call 2017). Raúl Guanche also acknowledges financial support from the Ramon y Cajal Program (RYC-2017-23260) of the Spanish Ministry of Science, Innovation and Universities

Efecto de la reflexión sobre la forma de equilibrio del perfil de playa: validación para la costa de la Península Ibérica

RESUMEN.El oleaje es el proceso dinámico más energético que afecta a la costa. La energía del oleaje incidente al alcanzar una playa sufre procesos de disipación y reflexión que van a tener una influencia distinta sobre la morfología del perfil. Se propone un perfil de equilibrio, considerando las diferentes fuerzas que actúan sobre el perfil: disipación por rotura y por fricción con el fondo. La aportación principal de este trabajo es la inclusión de la reflexión en el modelo. Como resultado se obtiene un perfil de equilibrio en dos tramos: perfil de rotura y perfil de asomeramiento, que describe de forma precisa la morfología de la playa. El modelo fue validado con perfiles medidos en la costa de la Península Ibérica. Los resultados permiten caracterizar y predecir la morfología del perfil de playa a partir de los coeficientes del modelo y su relación con las condiciones de oleaje y tamaño de grano.ABSTRACT.Waves are the most energetic process affecting the coastline. When the incident ware reaches the beach its energy is partially dissipated and partially reflected, changing the beatch profile. We propose a two-section equilibrium profile model based on the different forces that act along the beach: the breaker and the bottom friction dissipation. The improvement of this model is to incorporate reflection that under certain conditions has an important influence on the beach morphology. The proposed equilibrium beach profile is composed by a surf profile and a shoaling profile. The obtained expressions are composed by two terms associated to each wave phenomena. We have validated this model with measured profiles along the Iberian Península coast. The results allow characterization and prediction of the beach profile morphology using the coefficients, associated to the wave energy dissipation and reflection, and its relationship with wave climate conditions and grain size

Working with nature to enhance beach accretion: laboratory experiments of beach ploughing

Beach accretion is the natural mechanism that allows dry beaches to recover. Human response to climate change produces hardening of the coasts and the incident marine climate, which increases beach erosion produced during winter and prevents a full recovery during summer. Beach nourishments are performed all around the world to fight coastal erosion with a nature-friendly philosophy. Softer techniques as beach scraping are also widely applied. A kind of beach scraping is proposed here as an innovative nature-assisted beach enhancement technique, that aims to accelerate naturally produced sand accretion on the beach profile. It consists of mechanically ploughing the intertidal area of a beach to create ridges and furrows. Prototype-scale laboratory experiments were performed to analyse its effectiveness under controlled conditions. Seven 1 h tests having different water levels and the same initial bottom geometry and sea state conditions (Hs = 0.3 m, Tp = 7 s) were performed. Sea state, sand, and initial slope characteristics assured accretive conditions. Ploughed and flatbed initial slope geometries were simultaneously tested into two sub-channels of the wave flume. The results indicate that the bottom roughness is 3.57 times larger for the ploughed geometry. Consequently, wave energy dissipation is larger for the ploughed geometry, and therefore, the significant wave height at the shoreward end of the study area is 11% smaller for the ploughed geometry. This smaller wave height under the ploughed morphology leads to more accretive conditions, as observed from the measured onshore sediment transport, which is 2.9 times larger than the natural transport, and the larger accreted sediment volume in all seven test cases. These results demonstrate the effectiveness of ploughing to enhance natural beach accretion under highly probable accretion conditions. Further research is required to define the thresholds of marine conditions in which the potential of beach ploughing can be exploded.This work was developed under the Beach-ART project, which is funded by the Spanish Ministry of Economy, Industry, and Competitiveness under grant BIA2017-89491-R. The authors acknowledge the financial support from the Government of Cantabria through the Fénix Programme. The authors are grateful for the technical assistance of all the laboratory personnel during the experiments. Íñigo Aniel-Quiroga acknowledges the support of the University of Cantabria postdoc programme “Augusto G. Linares”

Análisis de estabilidad ante tsunami de diques rompeolas de materiales sueltos basado en ensayos de laboratorio

Los autores quieren agradecer la financiación de este trabajo al proyecto ASTARTE (Assessment, Strategy and Risk Reduction for Tsunamis in Europe, FP7/2007-2013 nº603839)

Análisis de las presiones en el espadón de diques en talud bajo la acción de tsunamis, basado en ensayos de laboratorio

Los autores quieren agradecer la financiación de este trabajo al proyecto ASTARTE (Assessment, Strategy and Risk Reduction for Tsunamis in Europe, FP7/2007-2013 nº603839)

Plataforma semisumergible triángular para aplicaciones en mar abierto

Una plataforma semisumergible que comprende: una columna interior configurada para dotar de mayor flotabilidad y tres columnas exteriores, donde cada una de dichas columnas interior y exteriores comprenden una base resistente y un tronco, y donde cada columna comprende una sección de mayor resistencia a una determinada altura y una pluralidad de vigas que unen cada columna exterior con la columna interior y cada columna exterior con las otras dos columnas exteriores. Un método de construcción de una plataforma semisumergible.Solicitud: 201200759 (18.07.2012)Nº Pub. de Solicitud: ES2387342A1 (20.09.2012)Nº de Patente: ES2387342B2 (10.02.2014