Hydraulic and coastal engineering

HYDRAULIC ANDCOASTALENGINEERING 

DESIGN AND ANALYSIS OF STRUCTURES EXPOSED TO HYDRODYNAMIC ANDCOASTAL PROCESSES

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HYDAULIC AND COASTALENGINEERINGDESIGN AND ANALYSIS OF STRUCTURES EXPOSED TOHYDRODYNAMIC AND COASTAL PROCESSES

Coastal and marine structures aresubject to the changingmeteorological and oceanographicconditions in terms of wind, waves,current and water levels. This has tobe taken into account in the design,but also the effect of the structureson the local conditions often has tobe analysed. This could be theinfluence from a breakwater on thewave climate and the effect on thecurrent conditions and sedimenttransport in the area. The mosteffective tool for evaluating thehydrodynamic and oceanographicconditions is numerical hydraulicmodels.

Wave models

Wave modelling constitutes one ofthe core areas in Rambolls hydraulicexpertise. For analysing the waveclimate and design wave conditionswave modelling is often the besttool to use. On basis of bathymetryand meteorological data wavesgenerated in an enclosed area canbe analysed using a spectral wavemodel and in the same waytransformation of offshore waves tonear shore areas can be modelled.Setting up a spectral wave model isoften the first step in analysing thewave climate in a specific area. Thewave modelling can both be madefor representative directionalscenarios and for extreme eventssuch as typhoons or hurricanes. Detailed studies of wave tranquillityin ports and behind breakwaters is acentral part when optimizing thelayout and design. In ports wavedisturbance simulations areimportant in order to plan theberthing facilities and in relation todowntime analysis for the ships atthe harbour. The wave tranquillity

analyses are carried out using aBousssinesq wave model which iscapable of taking factors such asshoaling, refraction, diffraction andpartial reflection/transmission forirregular waves into account.

Sediment transport and coastalimpacts

Coastal structures often have aninfluence on the current conditionsand sediment transport in the area.Ramboll carries out analysis ofsediment transport problems suchas sedimentation in entrancechannels, coastal erosion andshoreline development, and also thenecessary sediment transportmodelling. Furthermore Rambollcarries out planning and design ofcoastal protection solutions,provides expert consultancy forshoreline management andprepares coastal protectionstrategies. 

Environmental impacts

For larger coastal and port projectsan environmental impactassessment is required. Analyses ofthe effect of dredging andreclamation on water quality andsedimentation will be analysedusing particle transport andsediment transport models. Theresults of the modelling will be fedin to the environmental assessmentand constitutes an important basis.Also blocking effects influencingthe current conditions and waterquality can be analysed by hydraulicmodelling.   

Design input

When designing structures incoastal and marine areas designcriteria’s for wind, waves, waterlevel and current are required.

Design criteria are evaluated basedon statistical analyses of extremeweather events. Complex problemsare evaluated on basis of in-situinvestigations and numericalmodelling using hydraulic models.

Metocean studies

When complete metocean studiesare required Ramboll provides allthe hydrodynamic modelling ofwaves, currents and water levels aswell as the data analyses. The dataanalyses will include extreme valueanalyses and exedance andpersistence probabilities as well aspresentation of data in rose plotsand scatter tables. All analyses willbe made with respect to directionalintervals and season.

Hydraulic modelling using MIKE byDHI

The internationally recognized MIKE21/3 and LITPACK modelsdeveloped by DHI are utilized toanalyse the hydrodynamic climateof coastal regions, wave modellingwell as sediment processes, coastaldevelopment and particledispersion in oceans, rivers andestuaries. The models are used byan experienced staff with expertisewithin ports, hydrodynamics andcoastal morphology.    Contact RambollPorts & MarineHannemanns Allé 532300 København S T +45 5161 1000F +45 5161 1001

Battleship Murmansk – Technicalevaluations, Norway - 1

The sunken Russian battleship"Murmansk" in Sørvær in northernNorway has been attemptedsalvaged. Breakwaters and retainingwalls were constructed around thebattleship, but damaged during astorm. Subsequently Ramboll hasbeen responsible for technicalevaluations of the design including ananalysis of design waves using MIKE21 SW and BW, to assess thecontractors design assumptions.

Coastal hydraulic assessment,Hambantota, Sri Lanka - 2

As part of the feasibility study for anew seaport at Hambantota, Rambollcarried out wave tranquillity analysesand simulated wave conditions for thenew harbour. Sediment transportanalyses were carried out to investi-gate possible sedimentation problemsin the entrance channel and the opti-mum arrangement of the entrancechannel and breakwaters suggested.Impacts on the coastal environmentwere investigated as part of an EIA. 

EIA for expansion of Port of Nuuk,Greenland - 3

In connection with an expansion ofthe Port of Nuuk to accommodatelarger container and cruise vesselsRamboll has performed an EIA for theport expansion, including hydraulicmodelling and assessments ofmanoevring conditions for the largevessels. The hydraulic assessmentconsisted of numerical modelanalyses for evaluating the currentconditions as well as sedimentdispersion modelling for evaluatingthe effect of dredging.