Showing papers on "Breakwater published in 2015"
TL;DR: In this paper, the authors deal with a historic overview of Colombian Caribbean coastal erosion, the calculus of associated magnitudes and deepens knowledge and understanding of the different factors that control this process.
133 citations
TL;DR: In this paper, the seismic dynamics of a composite breakwater on liquefiable seabed foundation is investigated using a fully coupled numerical model FSSI-CAS 2D.
72 citations
TL;DR: In this paper, a cylindrical floating breakwater (CFB) is proposed, which consists of two parts: a main body of rigid cylinders, and a flexible mesh cage containing a number of suspending balls that are intended to absorb the wave energy into their mechanical energy.
71 citations
TL;DR: Hard engineered structures such as seawalls, groynes and breakwaters are often built to reduce coastal erosion and maintain a minimum beach width for recreation along coast regions in China as discussed by the authors.
62 citations
TL;DR: In this paper, the authors studied the effect of entrapped air on wave loading on a coastal bridge deck due to nonlinear waves during a storm, where air may be fully or partially trapped between the girders.
54 citations
TL;DR: In this paper, a mathematical integrated model is developed to investigate the wave-induced sloping seabed response in the vicinity of breakwater, where the wave model is based on the Volume-Averaged/Reynolds Averaged Navier-Stokes (VARANS) equations, while Biot's consolidation equation is used to govern the soil model.
48 citations
TL;DR: In this article, an experimental measurement on a large-scale, multi-layered breakwater model is used to extensively validate a numerical model for wave interaction with permeable coastal structures, built in a generic multiphysics CFD code, FLOW-3D.
41 citations
TL;DR: This study demonstrates that ecologically degraded shorelines can be augmented with small-scale breakwaters at reasonable cost and that these complex structures can serve as habitat for filter-feeding bivalves, mobile invertebrates, and young fishes.
Abstract: Estuarine shorelines have been degraded since humans arrived in the coastal zone. In recent history, a major cause of habitat degradation has been the armoring of shorelines with vertical walls to protect property from erosive wave energy; however, a lack of practical alternatives that maintain or enhance ecological function has limited the options of waterfront residents and coastal zone managers. We experimentally investigated the habitat value of two configurations of submerged breakwaters constructed along an eroding shoreline in northwest Mobile Bay, AL (USA). Breakwaters comprised of bagged oyster shell or Reef Ball™ concrete domes were built by a community-based restoration effort. Post-deployment monitoring found that: bagged oyster breakwaters supported much higher densities of live ribbed mussels than Reef Ball breakwaters; both breakwater configurations supported increased species richness of juvenile and smaller fishes compared to controls; and that larger fishes did not appear to be affected by breakwater presence. Our study demonstrates that ecologically degraded shorelines can be augmented with small-scale breakwaters at reasonable cost and that these complex structures can serve as habitat for filter-feeding bivalves, mobile invertebrates, and young fishes. Understanding the degree to which these structures mitigate erosive wave energy and protect uplands will require a longer time frame than our 2-year-long study.
31 citations
TL;DR: In this paper, a large discussion is held internationally indicating that although the construction of harbours is meant to enhance tourism and local economy, it very often leads to environmental and socioeconomic failure that are analysed in the present paper.
Abstract: Harbours with protruding breakwaters that are built on coasts cause alterations to the wave field, which attacks the coastline adjacent to the structures. As a result, sandy beaches often start eroding. Examples from Greece and Cyprus are presented, veryfying that the causes of the phenomenon, which are (i) the obstruction of longshore sand movement, and (ii) the longshore sand transport from the wave-action zone to the calm wave-shelter zone triggered by wave diffraction, work almost always simultaneously and none can be underestimated. A large discussion is held internationally indicating that although the construction of harbours is meant to enhance tourism and local economy, it very often leads to environmental and socio-economic failure that are analysed in the present paper. In addition, the paper discusses the methods of beach protection in such cases and gives guidelines for following effective practices in Greece.
27 citations
TL;DR: In this paper, the water wave characteristics of Bragg reflections from a train of fixed floating pontoon breakwaters were studied numerically and a numerical model of boundary discretization type was developed to calculate the wave field.
25 citations
TL;DR: In this article, a mathematical model was used, which takes into account wave parameters, detached breakwater configuration, groins configurations, initial shoreline and bathymetry as input and provides shoreline changes.
TL;DR: In this paper, the authors tried to understand the processes leading to erosion hotspots and propose measures to manage the hotspots, which are mostly dependent on the morphology and coastal structures, and identified hotspots are down drift side of mudbanks, fishing gaps, down drift sides of coastal structures including harbor breakwaters, locations of slumping seawalls, mining sites, wave over topping sites and piecemeal maintenance locations of seawalls.
TL;DR: In this article, a case study focusing on Haydarpasa Port, located at the southern entrance of Istanbul Bosphorus Strait (North coast of the Sea of Marmara), is presented.
TL;DR: In this paper, the authors developed and applied a multicriteria decision evaluation and support system for evaluating adaptation options for coastal communities and found that, in the case of Little Anse, the strategic decision to protect the community by a new breakwater arm provided preferred measures for resilience and adaptive capacity.
Abstract: Small islands and coastal communities around the world are particularly vulnerable to climate change impacts, mainly from storm surge attributed to more frequent and severe coastal storms, and mounting sea-level rise. Coastal hazards including inundation, salinisation of the water supply, and land erosion all threaten vital infrastructure that support coastal communities. This research, part of the International Community-University Research Alliance (ICURA) C-Change project “Managing Adaptation to Environmental Change in Coastal Communities: Canada and the Caribbean”, develops and applies a multicriteria decision evaluation and support system for evaluating adaptation options for coastal communities. The paper estimates vulnerability, resilience, and adaptive capacity measures associated with adaptation strategies in coastal communities with respect to their environmental, economic, social, and cultural dimensions. Results are determined using a multi-participant formulation of the Analytical Hierarchy Process (AHP) for identifying multicriteria decisions as adaptation strategies in a specific coastal context. The application of the framework is conducted for the coastal community of Little Anse on Isle Madame, Nova Scotia. Specifically, the state of the Little Anse breakwater is analysed and adaptation options for protecting, accommodating, and retreating are presented and evaluated in the face of predicted storm scenarios. The results indicate that, in the case of Little Anse, the strategic decision to protect the community by a new breakwater arm provides preferred measures for resilience and adaptive capacity.
01 Jan 2015
TL;DR: In this paper, the authors investigated morphology change of the southern Sendai Coast due to the 2011 Tsunami by analyzing topography and aerial images before and after the tsunami and showed the characteristics such as erosion in the longshore direction behind seawalls, landward sediment transport during tsunami run-up, seaward sediment transport from shore during backwash especially through crevasses of the seawalls and coastal stabilization by coastal structures such as seawalls.
Abstract: We investigate morphology change of the southern Sendai Coast due to the 2011 Tsunami by analyzing topography and aerial images before and after the tsunami. The results show the characteristics such as erosion in the longshore direction behind seawalls, landward sediment transport during tsunami runup, seaward sediment transport from shore during backwash especially through crevasses of the seawalls, and coastal stabilization by coastal structures such as seawalls, breakwaters and headlands. At the seriously eroded Yamamoto Coast, more than half of the total amount of eroded shore sand above sea level was estimated to be transported seaward due to backwash. After 1 year from the tsunami, the eroded coasts were recovered to form pocket beaches. After another year, the coastal morphology had not changed apparently but seawalls started to be reconstructed. At present, after 3 years from the tsunami, the seawalls with a height of 7.2 m have been reconstructed along the coast. With the reconstruction, the foundation ground of the seawalls has been recovered, but the eroded beaches still remain disappeared. The coast act in Japan was established in 1956 to protect the coast from disasters, and amended in 1999 to also preserve both the coastal environment and its utilization. From the perspective of long-term coastal management, it is strongly required to consider the vision of the future coast.
TL;DR: In this article, the influence of relative breakwater width, relative depth of submergence of the breakwater and roughness of breakwater front slope on wave transmission is analyzed and discussed.
TL;DR: In this paper, a small scale physical model of OWC caisson breakwater is presented, where the model is fixed in the wave flume and the wave pressures acting on the structure are recorded.
Abstract: Wave energy is one of the most potential marine energy resources in Taiwan, especially in the northeast and east coast of Taiwan. There are numerous existing wave energy devices. Among them Oscillating Water Column (OWC) caisson breakwater is very suitable for the harbors in Taiwan. This multiple function structure can generate the electric power and protect the harbor. To evaluate the stability of OWC caisson breakwater, the loadings induced by wave acted on the OWC caisson breakwater are analyzed. Experiments of a small scale physical model of OWC caisson breakwater is presented in this study. The model is fixed in the wave flume and the wave pressures acting on the structure are recorded. It is found that wave pressure at oscillating water column caisson breakwaters is smaller than the wave pressure at vertical wall. The wave loadings calculated with the suggestion of Sainflou and Goda are compared with the test results. The applicability of the empirical formulas is also discussed. Under the selected wave condition, the Sainflou's formula overestimates the wave pressure acting on the OWC caisson breakwater. Goda's formula provides good estimation for the force estimation but tends to underestimate the momentum and could possibly result in structure overturning.
TL;DR: In this paper, no adequate research available on the responses of coastal morphodynamic to low-crested breakwaters along the cohesive shore has been conducted, since the shore responses to coastal structures vary widely am...
Abstract: There is no adequate research available on the responses of coastal morphodynamic to low-crested breakwaters along the cohesive shore. Since the shore responses to coastal structures vary widely am...
TL;DR: In this article, the authors provided a numerical modeling study in Kamaishi Bay, calculating the damage inflicted by tsunami waves on structures and coastlines in terms of the square of the Froude number and other calculated hydrodynamic parameters such as the distribution of instantaneous flow depths, maximum currents and water surface elevations that occurred during this catastrophic tsunami.
Abstract: The March 2011 Great East Japan Tsunami was one of the most disastrous tsunami events on record, affecting the east coast of Japan to an extreme degree. Extensive currents combined with flow depths in inundation zones account for this devastating impact. Video footage taken by the eyewitnesses reveals the destructive effect and dragging capability of strong tsunami currents along the coast. This study provides a numerical modeling study in Kamaishi Bay, calculating the damage inflicted by tsunami waves on structures and coastlines in terms of the square of the Froude number Fr
2
; and also other calculated hydrodynamic parameters, such as the distribution of instantaneous flow depths, maximum currents and water surface elevations that occurred during this catastrophic tsunami. Analyses were performed by using the tsunami numerical modeling code NAMI DANCE with nested domains at a higher resolution. The effect of the Kamaishi breakwater on the tsunami inundation distance and coastal damage was tested by using the conditions of "with breakwater," "without breakwater," and "damaged breakwater." Results show that the difference between the hydrostatic pressure on the seaward side of the breakwater and the leeward side of the breakwater is quite high, clarifying conditions contributing to failure of the breakwater. Lower water surface elevations were calculated in the case of a breakwater existing at the entrance, a partly valid condition for the damaged breakwater case. The results are different for current velocities and $$Fr_{\hbox{max} }^{2}$$
in the "with breakwater" condition due to the concentration of energy through the breakwater gaps.
TL;DR: In this article, the authors identify how breakwater geometry and orientation of gaps between individual breakwaters alter the direction of waves entering the gaps and change the asymmetry of the salients.
TL;DR: In this paper, a hybrid modeling of pore pressure damping in rubble mound breakwaters is presented, taking advantage of the strengths of each approach, after a validation of the numerical modeling using the experimental data, the numerical model is used to analyze the pressure field inside the breakwater.
TL;DR: In this paper, the effects of the tetrapod size and vertical walls of a rubble mound on the volume of wave overtopping under irregular wave conditions in coastal areas in Busan Yacht Harbor were examined.
Abstract: Coastlines are protected by breakwater structures against the erosion of sand or other materials along beaches due to wave action. This research examined the use of physical modeling to determine the effects of the tetrapod size and vertical walls of a rubble mound on the volume of wave overtopping under irregular wave conditions in coastal areas in Busan Yacht Harbor. In this analysis model, the structures were studied using irregular waves and the JONSWAP wave energy spectrum. To understand the effects of the tetrapod size and heights of the vertical wall, the study considered vertical walls of 0, 1.78, 6.83, and 9.33 cm with armor double layered material tetrapods of 8, 12, 16, and 20 tons. An extensive number of experiments covering a relatively large range of variables enabled a comprehensive discussion. First, in the presence of a short vertical wall, the water level played a key role in the overtopping discharge. In such circumstances, the values of the wave overtopping discharge decreased with increasing freeboard size. In the presence of a tall freeboard and middle, the value of the wave overtopping discharge was equally influenced by the vertical wall factor. Moreover, the tetrapod size decreased by an increase in the vertical wall factor, and relationship between them resulted in a short wall height. From an engineering point of view, considering a small water level may allow the choice of a shorter vertical wall, which would ultimately provide a more economical design.
TL;DR: In this article, the authors proposed to construct a submerged segmented breakwater at 4 m water depth up to a height of 3.5 m using sand filled geosynthetic tubes.
TL;DR: In this paper, an original method to estimate the energy transmission behind the breakwater, considering both the wave reflection and the energy dissipation due to the wave breaking over the break-water and the wave energy absorption, is presented.
TL;DR: In this paper, the authors examined the magnitude of the wave energy that can be captured through the slope breakwater over-topping by physical model simulations at the Laboratory of Coastal Engineering, Department of Civil Engineering, Hasanuddin University.
01 Jan 2015
TL;DR: In this paper, the effectiveness of an offshore breakwater for the 2011 off the Pacific Coast of Tohoku Earthquake Tsunami was examined by two-dimensional (2D), quasi-3D and three-dimensional numerical models.
Abstract: In this study, the effectiveness of an offshore breakwater for the 2011 off the Pacific Coast of Tohoku Earthquake Tsunami was examined by two-dimensional (2D), quasi three-dimensional (quasi-3D) and three-dimensional (3D) numerical models First, both 3D numerical models were applied to the behavior of tsunami inundation for Kamaishi Bay in Iwate Prefecture where an offshore deep-water breakwater was installed against an assumed tsunami before 2011 The numerical results indicate 20 % error of maximum inundation height compared with the post-event tsunami survey on the land It is found that the offshore breakwater significantly reduced the tsunami height on the land The reduction of tsunami height on the land gave about 30 % tax revenue in comparison with similar locations with or without breakwater Based on the results the construction and or rebuilding of damaged offshore breakwaters can be considered as a viable option against tsunami particularly in vulnerable areas
TL;DR: In this article, the results of an experimental investigation of the flow and turbulence at the armor layer of rubble-mound breakwaters during wave action were presented, where three parallel experiments were performed including (1) an impermeable smooth breakwater slope, (2) a porous breakwater with large roughness elements added to the breakwater, and (3) a porosity core where the porous core was added below the break-water front.
Abstract: This paper presents the results of an experimental investigation of the flow and turbulence at the armor layer of rubble-mound breakwaters during wave action. The study focused on the details of the flow and turbulence in the armor layer and on the effect of the porous core on flow and stability. To isolate the processes involved with the flow in the porous core, experiments were conducted with increasing complexity. Specifically, three parallel experiments were performed including (1) an impermeable smooth breakwater slope, (2) an impermeable breakwater slope with large roughness elements added to the breakwater, and (3) a porous breakwater where the porous core was added below the breakwater front. One breakwater slope of 1:1.5 was applied. In this paper the focus is on the details of a single sequence of wave approach, run-up, and rundown. To isolate this sequence the experiments were performed applying a solitary wave. The individual sources of turbulence generation were distinguished using La...
TL;DR: In this article, a numerical model for the redesign of the existing and future ports and coastal defence structures is presented, mainly based on the higher order Boussinesq equations and describes nonlinear wave transformation in the surf and swash zone, wave structure interaction, breaking wave induced currents and morphological changes.
Abstract: In the present work, a numerical model for the redesign of the existing and future ports and coastal defence structures is presented. The model is mainly based on the higher order Boussinesq equations and describes nonlinear wave transformation in the surf and swash zone, wave structure interaction, breaking wave induced currents and morphological changes. The existing model is adapted to describe climate change impacts on coastal flooding/erosion, ports and coastal defence structures. Model applications result to the estimation of: wave overtopping over the breakwaters crests, wave entering the harbour basin through diffraction, coastal erosion and storm surge/wave flooding. The model provides coastal engineers with a useful tool for the redesign of the existing coastal structures.
TL;DR: In this paper, a semi-empirical equation for the co-efficient of wave transmission in reef breakwaters is derived from dimensional analysis as semi empirical equation which involves different parameters like wave characteristics, reef dimensions and nominal diameter of armour units.
TL;DR: In this article, the authors present results of monitoring beach activities, which indicate that erosion processes are occurred due to the jetty construction of Batang Commercial Port, which cause disturbance of longshore transport equilibrium.