PART III FACILITIES, CHAPTER 4 PROTECTIVE FACILITIES FOR ...ocdi.or.jp/tec_st/tec_pdf/tec_dw/tech_635_675.pdf · (4) The curtain wall breakwaters can be broadly divided into the single-curtain-walled

PART III FACILITIES, CHAPTER 4 PROTECTIVE FACILITIES FOR HARBORS

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3.8 Pile-type Breakwaters Public NoticePerformance Criteria of Pile-type Breakwaters

Article 36 Theperformancecriteriaof thepile-typebreakwatersunder thevariableaction situations, inwhich thedominantactionsarevariablewavesandLevel1earthquakegroundmotions,shallbeasspecifiedinthesubsequentitems:(1)Theriskthattheaxialforceactingonthepilesmayexceedtheresistancebasedonfailureoftheground

shallbeequaltoorlessthanthethresholdlevel.(2)Theriskthatthestressgeneratedinthepilesmayexceedtheyieldstressshallbeequaltoorlessthan

thethresholdlevel.

[Commentary]

(3)PerformanceCriteriaofPile-typeBreakwaters①Pile-typebreakwaters

Settingsoftheperformancecriteriaandthedesignsituationsexcludingaccidentalsituationsofpile-typebreakwatersshallbeasshowninAttached Table 19. Theperformancecriteriaofthesuperstructureandcurtainwallofpile-typebreakwatersshallbeequivalenttothesettingsinArticle 23throughArticle 27,correspondingtothetypeofmemberscomprisingtheobjectivepile-typebreakwater.

Attached Table 19 Settings for Performance Criteria and Design Situations (excluding accidental situations) of Pile-type Breakwaters

MinisterialOrdinance PublicNotice

Performancerequirements

Designsituation

Verificationitem Indexofstandardlimitvalue

Article

Paragraph

Item

Article

Paragraph

Item Situation Dominating

actionsNon-

dominatingactions

14 1 2 36 1 1 Serviceability Variable Variablewaves Selfweight,waterpressure

Axialforceactingonpiles

Resistancebasedonfailureofground(pushingandpulling)

2 Level1earthquakegroundmotion

Selfweight,waterpressure

Yieldingofpiles

Variablewaves Selfweight,waterpressure

Axialforceactingonpiles

Designyieldstress

Level1earthquakegroundmotion

Selfweight,waterpressure

Yieldingofpiles

[Technical Note]

3.8.1 Fundamentals of Performance Verification

(1)Thepile-typebreakwaterscanbebroadlydividedintocurtainwallbreakwatersandsteelpipepilebreakwaters.Thecurtainwallbreakwaterisapermeablebreakwaterandwasdevelopedforuseinwaterswithacomparativelylowwaveheight,suchasenclosedbays,orlocationswithsoftseabottomground.Steelpipepilebreakwaterisbreakwaterinwhichthecurtainsectioniseliminatedandwavesarestoppedonlybythepiles.

(2)Forcurtainwallbreakwaters,itispreferabletoselectanappropriatestructureconsideringthecoefficientofwavereflectionandtransmission,andwhennecessary,toconducttheperformanceverificationbyperforminghydraulicmodeltests.

(3)AnexampleoftheperformanceverificationprocedureforcurtainwallbreakwatersisshowninFig. 3.8.1.

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TECHNICAL STANDARDS AND COMMENTARIES FOR PORT AND HARBOUR FACILITIES IN JAPAN

Verification of cross-sectional forces in superstructure

Variable situation in respect of wavesand Level 1 earthquake ground motion

Accidental situation in respect of Level 2earthquake ground motion,

tsunamis, and waves

Verification of joints between curtain wall and piles

Verification of stress and axial force in piles

Verification of cross-sectional forces in superstructure

Verification of stress and axial force in piles

Determination of layout

Determination of design conditions

Assumption of cross-sectional dimensions

Evaluation of actions

Determination of cross-sectional dimensions

Verification of structural members

*2

Performance verification Performance verification

*1

*1:Becauseassessmentoftheeffectsofliquefactionisnotshown,separateconsiderationisnecessary.*2:Forfacilitieswheredamage to thefacilitiescanbeassumedtohaveaserious impacton life,property,andsocialactivity, it is

preferabletoconductverificationforaccidentalsituationswhennecessary.Verificationforaccidentalsituationsinrespectofwavesshallbeconductedincaseswherefacilitieshandlinghazardouscargoesarelocateddirectlybehindthebreakwateranddamagetotheobjectivefacilitieswouldhaveacatastrophicimpact.

Fig. 3.8.1 Example of Performance Verification Procedure for Pile-type Breakwaters

(4)Thecurtainwallbreakwaterscanbebroadlydividedintothesingle-curtain-walledtypeandthedouble-curtain-walledtype,dependinghowtheso-calledcurtainwallsuchasconcreteplatesisarrangedrelativetothedirectionofwavepropagation.Furthermore,avarietyoftypesareconceivable,dependingontheshapeofthepilestructuresupportingthecurtainwallortheshapeofslitsprovidedinthecurtainwall.Examplesofthecrosssectionsofpile-typebreakwatersareshowninFig. 3.8.2.


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Curtain Pile

(a) Single-curtain-walled breakwater (vertical pile-type)

(b) Single-curtain-walled breakwater (coupled pile-type)

(c) Double-curtain-walled breakwater (rigid frame type)

(d) Double-curtain-walled breakwater (coupled pile-type)

Fig. 3.8.2 Examples of Cross Sections of Pile-type Breakwaters

(5)Curtainwallbreakwatersgenerallyhavethefollowingfeatures.

① The reflectioncoefficient canbe reduced soas to the same level as in thebreakwaters coveredwithwave-dissipatingblocksorless.

② Exchangeofseawatercanbeexpectedbytidesandwavespassingthroughslitsprovidedinthecurtainwallorthegapbetweentheloweredgeofthecurtainwallandtheseabed.

③Comparingthesingle-curtain-walledandthedouble-curtain-walledbreakwaters,becauseanenergydissipatingeffect can be expected between the front and the back curtain walls with the double-curtain-walled typebreakwater,reflectedwavesandtransmittedwavescanbereducedincomparisonwiththesingle-curtain-walledbreakwaters.

④ Becausethevelocityofflowspassingunderthecurtainwallisquitehigh,itisnecessarytotakeappropriatecountermeasurestopreventorsuppresswashing-outofsand.

3.8.2 Actions

Itisnecessarytosetthewaveforceactingonthecurtainwallbreakwatersbasedontheresultsofhydraulicmodeltests,numericalanalysis,orappropriatecalculationformulas.Whenusingthesingle-curtain-walledbreakwater,theresultobtainedbysubtractingthewavepressuredistributionactingdeeperthantheloweredgeofthecurtainwallfromthewavepressuredistributionshowninPart II, Chapter 2, 4.7 Wave Pressure and Wave Forcecanbeusedasthewaveforceactingonthecurtainwall.

3.8.3 Setting of Basic Cross Section

(1)Thestructuraltypeandtheshapeofcurtainwallbreakwatersshallbedeterminedconsideringtheconditionofseastatesinthearea,thetargetreflectioncoefficient,thetargettransmissioncoefficientandconstructability.

(2)Insettingthecrosssectionofthecurtainwallbreakwaters,includingthecrownheight,thedepthofthelowerendofthecurtainandthesizeoftheslitsprovidedinthecurtain,andinthecaseofthedouble-curtain-walledbreakwaters,andthespacingbetweenthecurtainwalls,itispreferabletosetthecrosssectionbasedonmodeltestsadapted to theconditions. It ispreferable that thedimensionsofmemberssuchas thecurtainwall,andpilesbedeterminedappropriatelyconsideringthespacingbetweenthepilesinthedirectionofthebreakwaterextension.

(3)Examplesofmodeltestsforthesingle-curtain-walledbreakwatersinclude,forexample,modeltestsbyMorihiraetal.57)ThedepthofthelowerendofthecurtainwallcanbeobtainedfromFig. 3.8.3ifthewavetransmissioncoefficientisdetermined,andthecrownheightofthecurtainwallcanbeobtainedfromFig. 3.8.4.Provided,

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however,thatthecrownheightofthecurtainin Fig. 3.8.4wascorrectedsothatR/H=1.25atd/h=1.0,anddoesnotshowacrestcapableofcompletelypreventingwaveovertopping.Inthefigure,disthedepthofthelowerendofthecurtain,histhewaterdepth,Listhewavelength,Risthecrownheightofthecurtain,andHisthewaveheight.TherelationshipwiththewavereflectioncoefficientofwavesbyasinglecurtainwallisshowninFig. 3.8.5.

(4)In steel pipe pile breakwaters, if the steel pipes are drivenwith a space between the piles, the structure canfunctionasapermeabletypebreakwater.AccordingtotheresearchbyHayashietal.,53)therelationshipbetweenthepilespacing/pilediameterratiob/DandthecoefficientofwavetransmissionγTisasshowninFig. 3.8.6. Themomentduetowaveforcedecreasesasthespacingbetweenthepilesisincreased,butthiseffectreachestothelimitataroundb/D=0.1.Withthistypeofbreakwater,cautionshouldalsobepaidregardingscouringofthegroundbetweenthepiles.

1.0

0.680

0.6 0.8 1.0d/h

0.4

0.8

0.6

0.4

0.2

0 0

0.340

0.235

0.170

0.1410.097

h/L=0.078

0.2

=Tr

ansm

itted

wav

e he

ight

(HT)

In

cide

nt w

ave

heig

ht (H

I)W

ave

heig

httra

nsm

issi

on c

oeff

icie

nt

Fig. 3.8.3 Relationship between d/h and Coefficient of Wave Transmission (Single Curtain Wall)

Fig. 3.8.4 Calculated Curve of Crown height (Single Curtain Wall)


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0.6 0.8 1.0d/h

0.40 0.20

20

40

60

80

100

:h/L=0.235: =0.097

Ref

lect

ion

Coe

ffic

ient

Kr (

%)

Fig. 3.8.5 Relationship between d/h and Wave Reflection Coefficient (Single Curtain Wall)

Test Values

Hayashi, etc.Theoretical valueby Wiegel

WiegelHayashi, etc.

b/D h:water depth

0 0.2 0.4 0.6 0.8 1.00

0.2

0.4

0.6

0.8

1.0h/H1=5

h/H1=4

γ T( =HT/H

I)

Fig. 3.8.6 Relationship between Ratio of Pile Spacing/Pile Diameter and Coefficient of Wave Transmission 53)

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3.9 Breakwaters with Wide Footing on Soft Ground[Commentary]

(1)BreakwaterswithWideFootingonSoftGround(pilefoundation)Becausebreakwaterswithawidefootingonsoftgroundwithapilefoundationareastructuraltypewhichhastherespectivestructuralfeaturesofthegravity-typebreakwaterandthepile-typebreakwater,theperformancecriteriaforbreakwaterswithwidefootingonsoftgroundareequivalenttotherespectivesettingsinthePublicNotice,Article35PerformanceCriteriaforGravity-typeBreakwatersandArticle36PerformanceCriteriaforPile-typeBreakwaters.

[Technical Note]


(1)Breakwaterswithwidefootingonsoftground(hereafter,softlandingbreakwaters)resistagainstthehorizontalwaveforceby thepilesandthecohesionbetweenthebottomof thebreakwaterbodyandthesurface layerofthecohesivesoil. Ontheotherhand,thebottomslabandfootingresistagainsttheverticalforce.Ingeneral,becausethistypeofstructureisdevelopedforconstructionofbreakwatersonsoftcohesivesoil,therearecaseswherethistypeiseconomicallyadvantageousbecausetheweightofthebreakwaterbodycanbereducedandsoilimprovementisnotrequired.

(2)ExamplesofthecrosssectionsofsoftlandingbreakwatersareshowninFig. 3.9.1.Althoughstructuraltypescanbebroadlydividedintothe“flatbasetype”andthe“flatbasetypewithpiles,”theflatbasetypewithpilesisgenerallyused.

Soft groundSoft ground

Steel pilesSteel piles

Soft groundSoft ground

(a) Flat base type/inverted T type

(b) Flat base type with piles/inverted π type

Fig. 3.9.1 Examples of Cross Sections of Soft Landing Breakwaters

(3)Becausethesoftlandingbreakwaterisconstructeddirectlyonsoftground,itisaffectedbyscouringbywavesandwatercurrentsintheareaaroundthebreakwaterbody.Therefore,appropriatecountermeasuresshallbetakenasnecessary.


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3.10 Floating Breakwaters Public NoticePerformance Criteria of Floating Breakwaters

Article 37 Theperformancecriteriaoffloatingbreakwatersunderthevariableactionsituation,inwhichthedominantactionisvariablewaves,shallbeasspecifiedinthesubsequentitems:(1)Theriskofcapsizingofthefloatingbodyshallbeequaltoorlessthanthethresholdlevel.(2)Theriskofimpairingtheintegrityofthemembersofthefloatingbodyshallbeequaltoorlessthanthe

thresholdlevel.(3)Theriskthatthestressgeneratedinmooringlinesmayexceedtheyieldstressshallbeequaltoorless

thanthethresholdlevel.(4)Theriskoflosingthestabilityduetotractiveforceactingonthemooringanchorshallbeequaltoor

lessthanthethresholdlevel.

[Commentary]

(1)PerformanceCriteriaofFloatingBreakwaters①Settings in connectionwith theperformance criteria and thedesign situation excluding accidental

situationsoffloatingbreakwatersshallbeasshowninAttached Table 20.

Attached Table 20 Settings in Connection with Performance Criteria and Design Situations (excluding accidental situations) of Floating Breakwaters



Designsituation


Article

Paragraph

Item

Article

Paragraph


actionsNon-

dominatingactions

14 1 2 37 1 1 Serviceability Variable Variablewaves Selfweight,wind,waterpressure,watercurrents

Capsizingoffloatingbody

Limitvalueforcapsizing

2 Integrityofmembers

-

3 Yieldingofmooringlines

Designyieldstress

4 Stabilityofmooringanchor,etc.

Resistance (horizontal andvertical)ofmooringanchor

②Stabilityofmooringanchor(serviceability)Mooringanchorisacollectivetermforequipmentplacedonthesurfaceoftheseabottomtofixthefloatingbody.Concretely,inadditiontothemooringanchors,sinkersarealsoincluded.

[Technical Note]


(1)Floatingbreakwatersarebreakwatersinwhichtransmittedwavesarereducedbymooredfloatingbody.Althoughtheshapesofthefloatingbodyincludemanytypes,thepontoontypeiswidelyused.

(2)AnexampleoftheperformanceverificationprocedureforfloatingbreakwatersisshowninFig. 3.10.1.

(3)Thefloatingbreakwatershavevariousadvantages,includingthefactthattheydonotpreventmovementofseawaterandlittoraldrift,theyarenotaffectedbytidallevelschangesorgroundconditions,andtheyaremoveable.However, they also have numerous problems, in that they allow large transmittedwaves, their effects differremarkablydependingonthecharacteristicsofwaves,theycanonlybeusedinlocationswithsmallwavesduetotheirlimitedwaveresistance,andthemechanismofresistanceoftheanchorsystemagainstrepeatedimpulsiveactionsisnotadequatelyunderstood.Furthermore,becausethereisadangerofsecondarydamageduetodriftingofthefloatingbodyifthemooringlinesbreak,appropriatemeasuresshouldbetaken.

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Performance verification of mooring lines, anchor, etc.

Performance verification of body section(floor slab, bottom slab, side walls and bulkheads)

Verification of capsizing and transmission coefficient

Performance verification of anchorand mooring line attachment parts

Variable situation in respect of waves

Performance verification of mooring lines and anchor

Performance verification of body section(floor slab, bottom slab, side walls and bulkheads)

Accidental situation in respect oftsunamis and waves

Determination of layout

Determination of design conditions

Assumption of cross-sectional dimensionsincluding draft and freeboard

Evaluation of actions

Determination of cross-sectional dimensions

Verification of joints and attachment parts

*1

Performance verificationPerformance verification

*1:For facilitieswheredamage to the facilitiescanbeassumed tohavea serious impacton life,property,andsocialactivity, it ispreferabletoconductverificationforaccidentalsituationswhennecessary.Verificationforaccidentalsituationsinrespectofwavesshallbeconductedincaseswherefacilitieshandlinghazardouscargoesarelocateddirectlybehindthebreakwateranddamagetotheobjectivefacilitieswouldhaveacatastrophicimpact.

Fig. 3.10.1 Example of Performance Verification Procedure for Floating Breakwaters

3.10.2 Setting of Basic Cross Section

Thelayoutandtheshapeofthefloatingbreakwatersshouldbesetsothattherequiredharborcalmnesscanbeobtained.Indeterminingthesesettings,itispreferabletomeasurethewavetransmissioncoefficientbyconductinghydraulicmodel tests. As theoretical analysismethods, Ito et al.59) proposedanapproximationmethod for themotionof a2-dimensionalrectangularfloatingbody,andIijima60)proposedatheoryinconnectionwithfreefloatingbodies.

3.10.3 Performance Verification

(1)TheperformanceverificationofmooringsystemcanbeconductedreferringtoPart II, Chapter 2, 4.9 Actions on Floating Body and its Motions.

(2)Mooring-relateddesigncanbedividedintotwostages:

① Firststageinwhichthetensionsthatwillbeexertedonmooringlinesandsinkersaredeterminedthroughstaticanddynamicanalysesbyassumingvariousconditionsconcerningmooring-relatedmatterssuchasthemooringmethodandlinelength.


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② Secondstageinwhichdetaileddesignoftheactualmooringlinesandsinkersiscarriedoutandthestabilityisconfirmed,basedonthetensionsandotherfindingsinthefirststageabove.

(3)Dynamicanalysisofthemooringlinesconsistsofdeterminingthefluctuatingtensionanddisplacementthatarisefromthemotionsoffloatingbody.Thisanalysiscanbeclassifiedintothefollowingtwoprocedures:

①Methodstoanalyzethesefactorsbasedonthestaticmooringcharacteristics.

②Methodstoanalyzethesefactorsbasedonthedynamicresponsecharacteristicsofmooringlines.

(4)Theperformanceverificationforthemooringanchorisequivalenttothatforfloatingpiers.Inadditiontoreferringto Chapter 5, 6.4 Performance Verification,Reference62)canalsobeusedasareference.

(5)Thestructureofthefloatingbodyofafloatingbreakwatershallpossessadequatesafetyasawhole,andshallalsopossessadequatelocalstrength.Withstructureshavingarelativelylonglengthrelativetotheirwidthanddepth,suchasfloatingbreakwaters,itisgenerallypreferabletoexaminethefollowingpoints.Longitudinal strength: The cross-sectional forces such as longitudinal flexural moment, shearing force andtorsionalmomentinthepermanentsituationandunderactionofwavesshallbeobtainedforthefloatingbodyasawhole.Lateral strength: The cross-sectional forces such as flexural moment and shearing force in the directionperpendiculartothelongitudinalaxisunderactionofwavesshallbeobtainedforthefloatingbodyasawhole.Localstrength:Thecross-sectionalforcessuchasflexuralmomentandshearingforcegeneratedinindividualwallpanelsandgirdersshallbeobtained.

(6)Longitudinalstrengthcalculationmethodsaredividedintotwocategories,oneofwhichconsidersfloatingbodymotions,whileotherthatdoesnot.Amongcalculationmethodsthatdonotconsiderfloatingbodymotions,theMullerequation, thePrestressedConcreteBargeStandards,andtheVeritusRulearefrequentlyused. Ontheotherhand,theUeda'sformulae63)isusedasacalculationmethodthatdoestakeintoaccountthefloatingbodymotions.AcomparisonofthemethodsofbothcategoriesiscitedintheReferences63),whichcanbereferredtowhenapplyingthecalculations.

(7)Theperformanceverificationforthestabilityofthefloatingbodyisequivalenttothatforfloatingpier.Chapter 5, 6.4 Performance Verification canbeusedasareference.Forotherconceptsinconnectionwiththeverificationofstabilitywheninundated,Reference64)canbeusedasareference.

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45) Jarlan,G.E.:Aperforatedverticalwallbreakwater,TheDockandHarbourAuthority,Vol.41No.488,PP.394-398,196146) Hosokawa,T.,E.Miyoshi andO.Kikuchi:Experiments onHydraulicCharacteristics andAerationCapacity of theSlit

CaissonTypeSeawall,TechnicalNoteofPHRINo.312,p.23,197947) Morihira,M.,H.SasajimaandS.Kubo:Fish reef effectofperforatedwall,Proceedingsof26thConferenceonCoastal

Engineering,JSCE,pp.348-352,197948) CoastalDevelopmentInstituteofTechnology:TechnicalManualforNew-typebreakwaters,199449) TANIMOTO,K., andYasutoshiYOSHIMOTO:Theoretical andExperimentalStudyofReflectionCoefficient forWave

DissipatingCaissonwithaPermeableFrontWall50) Hosoyamada,T.,S.TakahashiandK.Tanimoto:Applicabilityofsloping-topbreakwaterinisolatedislands,Proceedingsof

CoastalEngineering,JSCE,Vol.41,PP.706-710,199451) Sato,T.N.Yamagata,M.Furukawa,S.TakahashiandT.Hosoyamada:Hydrauliccharacteristicsofsloping-topbreakwaters

armouredwithwave-absorbingblocks-DevelopmentofanewstructuraltypeofbreakwatersindeepwaterareainNahaPort-,ProceedingsofCoastalEng.JSCEVol.39,pp.556-560,1992

52) Nakata,K.,T. Ikeda,M.Iwasaki,Y.KitanoandT.Fujita:Hydraulicmodelexperimentofsloping-topbreakwater in thecourseoffieldconstructionwork,,Proceedingsof30thConferenceonCoastalEngineering,JSCE,pp.313-316,1983

53) Hayashi,T.,T.Kano,M.SiraiandS.Hattori:Hydrauliccharacteristicsofcylindricalpermeablebreakwater,Proceedingsof12thConferenceonCoastalEngineering,JSCE,pp.193-197,1965

54) Nagai,S.,T.KuboandK.Okinawa:Fundamentalstudyonsteelpipebreakwater‘IseReport),Proceedingsof12thConferenceonCoastalEngineering,JSCE,pp.209-218,1965

55) Nakamura,T,H.Kamikawa,T.KounoandK.Kimoto:Structuraltypeofcurtainwallbreakwaterthatmakesthereductionoftransmitandreflectedwavespossible,ProceedingsofCoastalEngineering,JSCE,Vol.46,pp.786-790,1999

56) Okiya,T.,T.Sakakiyama,M.Shibata,O.NakanoandY.Okuma:Characteristicsofwaveforceoncurtainwallstructurehavingpermeablelowerportion,ProceedingsofOffshoreDevelopment,Vol.46,pp.791-795,1999

57) Morihira.M.,S.KakizakiandY.Goda:Experimentalinvestigationofcurtain-wallbreakwater,Rept.ofPHRIVol.3No.1,1964

58) ShimonosekiportandAirportTechnicalSurveyOffice,Kyu-shuRegionalDevelopmentBureauHomePage:DesignManualforbreakwaterswithwidefootingonsoftground(Draft),http:〃www.gityo.gojp/,2005

59) Itou,Y.andS.Chiba:AnApproximateTheoryofFloatingBreakwaters,Rept.ofPHRIVol11No.2,pp.43-77,197260) Ijima, T.,M. Tabuchi and Y. Yumura:Motions of Rectangular-cross-section floating body due to wave action and the

transformationofwaves,ProceedingsofJSCE,No.202,pp.33-48,197261) JapanInternationalMarineScienceandTechnologyFederation:FloatingBreakwaters-Presentstatusandproblems-.198762) JSCER:Guidelineandcommentaryfordesignofoffshorestructures(Draft),197363) UEDA, S., Satoru SHIRAISHI andKazuoKAI: CalculationMethod of Shear Force andBendingMoment Induced on

PontoonTypeFloatingStructuresinRandomSea,TechnicalNoteofPHRINo.505,p.27,198464) Oogushi,M:.Theoreticalnavalarchitect,Kaibun-doPublishing,1991

–646–


4 Amenity-oriented BreakwatersItisnecessarytoexaminethecrownheightoftheamenity-orientedbreakwaterswhichwillbevisitedbythegeneralpublicfromtheviewpointofpublicuseandsafety,includingspray,andthewaveovertopping.

References

1) CoastalDevelopmentInstituteofTechnology:TechnicalManualfortheImprovementofPortenvironment,19912) TAKAHASHI,S.,KimihikoENDOHandZen-ichirouMURO:ExperimentalStudyonPeople’sSafetyagainstOvertopping

WavesonBreakwaters-AstudyonAmenity-orientedPortStructures(2ndRept.)-,Rept.ofPHRIVol.31No.4,1992


–647–

5 Storm Surge Protection Breakwaters Theperformanceverificationforstormsurgeprotectionbreakwaterscanbeconsideredequivalentto3 Ordinary Breakwaters.Inadditiontothis,thefollowingpointsneedtobeconsideredcorrespondingtothestructuraltype.

5.1 Fundamentals of Performance Verifi cation

(1) In the storm surge protection breakwaters, it is necessary to set the layout, and crown height appropriately,consideringtheeffectofthebreakwaterinreducingtheeffectsofstormsurge.

(2)Inthestormsurgeprotectionbreakwaters,inadditiontothestabilityofthefacilitiesagainsttheactionofwaves,itisalsonecessarytosecurethestabilityofthefacilitiesconsideringthecharacteristicsofattackbystormsurgessuchastheriseinthewaterlevelinsidethebreakwater.

5.2 Actions Intheexaminationofthestabilityoftheuprightsection,theriseinthewaterlevelinsidethebreakwaterduetotheinflowofthestormsurgeshallbeconsidered.Inthiscase,Part II, Chapter 2, 4 WavesandPart II, Chapter 2, 3 Tidal Levelcanbeusedasareferenceforwavesandtidallevels,respectively.

5.3 Setting of Basic Cross Section The crownheight of the storm surgeprotectionbreakwaters shall be the required height basedon appropriateconsiderationofthewavesandtidallevelsattheconstructionsite.Forwavesandtidallevels,Part II, Chapter 2, 4 WavesandPart II, Chapter 2, 3 Tidal Levelcanbeusedasareference,respectively.

References

1) JSCE:Handbookofcoastalfacilities(2009Edition),pp465-468,2000

–648–


6 Tsunami Protection Breakwaters The performance verification for tsunami protection breakwaters can be considered equivalent to3 Ordinary Breakwaters.Inadditiontothis,thefollowingpointsneedtobeconsidered,correspondingtothestructuraltype.

6.1 Fundamentals of Performance Verification

(1) Itisnecessarytosetthelayoutand,crownheightofthetsunamiprotectionbreakwaters,appropriately,consideringtheeffectofthebreakwaterinreducingtheeffectsoftsunamis.

(2)Inadditiontothestabilityagainsttheactionofwaves,itisalsonecessarytosecurethestabilityofthetsunamiprotectionbreakwatersconsideringthecharacteristicsduringtsunamiattack.

6.2 Actions

(1)Fortsunamis,Part II, Chapter 2, 5 Tsunamiscanbeusedasareference.

(2)In the performance verification for tsunamis, it is preferable that the difference in thewater level inside andoutside thebreakwaterduringactionof tsunamisbeevaluatedappropriatelybasedonanumericalsimulation.Attentionshouldbepaidtothefactthatthewaterlevelbehindthebreakwaterwillnotnecessarilybethesameasthestillwaterlevel,dependingoninflowandoutflowoftsunamis.

(3)Inthecalculationoftsunamiforce,Part II, Chapter 2, 5(7) Tsunami Wave Forcecanbeusedasareference.However,becausemanypointsstillrequireclarification,itispreferabletoconfirmthewaveforcebyanappropriatemethodsuchashydraulicmodeltestsorthelike.

6.3 Setting of Basic Cross Section Itisnecessarytosetthecrownheightofthetsunamiprotectionbreakwaterstothecrownheightrequiredagainstwaveovertoppinginbothcasesofactionofwavesandtsunamisatappropriatelysettidallevels.

6.4 Performance Verification

(1) In theperformanceverificationof the tsunamiprotectionbreakwaters in theaccidental situation in respectoftsunamis,ingeneral,anexaminationshallbeperformedforthestabilityagainstslidingandoverturningoftheuprightsectionandthefailureduetoinsufficientbearingcapacityofthefoundationground.

(2)Intheexaminationofthestabilityagainstslidingandoverturningoftheuprightsectionfortsunamis,equation(6.4.1) andequation (6.4.2) canbeused. In the followingequations, thesymbolγ is thepartial factor for itssubscript,andthesubscriptsddenotethecharacteristicvalue.

① Sliding

(6.4.1)where

f :frictioncoefficientbetweenbottomofwallbodyandfoundation W :weightofbody(kN/m) PB :buoyancy(kN/m) PU :upliftforceoftsunami(kN/m) PH :horizontalwaveforceoftsunami(kN/m) γa :structuralanalysisfactor

② Overturningofbreakwaterbody

(6.4.2)where

W :weightofbody(kN/m) PB :buoyancy(kN/m) PU :upliftoftsunami(kN/m) PH :horizontalwaveforceoftsunami(kN/m) a1–a4:arm lengths of actions (see Fig. 3.1.4 of 3.1 Gravity-type Breakwaters (Composite

Breakwaters)) γa :structuralanalysisfactor


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ThedesignvaluesofwaveforcePHdandPUdinequation (6.4.1)andequation (6.4.2)canbecalculatedusingequations(5.4)and(5.5)inPart II, Chapter 2, Section2, 5 Tsunamis.ThedesignvalueoftheweightofthebreakwaterbodyWdcanbecalculatedusingequation(3.1.4) in3.1 Gravity-type Breakwaters (Composite Breakwaters). When caissons do not have a footing, equation (3.1.5) in 3.1 Gravity-type Breakwaters (Composite Breakwaters)canbeusedincalculatingthedesignvalueofbuoyancyPBd.

(3)The examination for the failuredue to insufficientbearingcapacityof the foundationground for tsunamis isequivalent to that for variable situations in respect of waves in composite breakwaters. 3.1.4 Performance Verificationcanbeusedasareference.Provided,however,thatthepartialfactorsusedinverificationshallbeinaccordancewiththefollowing(4) Partial factors.

(4)PartialfactorsForthepartialfactorsusedintheexaminationofthestabilityagainstslidingandoverturningoftheuprightsectionandthefailureduetoinsufficientbearingcapacityofthefoundationgroundfortsunamiprotectionbreakwatersintheaccidentalsituationinrespectoftsunamis,thevaluesinTable 6.4.1canbeusedasareference.Provided,however,thatthevaluesshowninTable 6.4.1arethestandardvalueswhensettingthetsunamiforceofthelargestclassastheaccidentalactionexpectedatthelocationwherethefacilitiesaretobeconstructed.Here,incaseswhereuncertaintyisexpectedincalculationofthecharacteristicvalueofthetsunamiforce,thereareexamplesinwhich1.2issetasastructuralanalysisfactor.

Table 6.4.1 Partial Factors for use in Performance Verification of Tsunami Protection Breakwaters

γ α μ/Xk V

Sliding

γf Frictioncoefficient 1.00 – – –γPH,γPU Tsunamiforce 1.00 – – –γwl rwl=1.5 1.00 – – –

rwl=2.0,2.5 1.00 – –H.H.W.L. 1.00 – –

γWRC UnitweightofRC 1.00 – – –γWNC UnitweightofNC 1.00 – – –γWSAND Unitweightoffillingsand 1.00 – – –γa Structuralanalysisfactor 1.00orover – – –

Overturning

γPH,γPU Tsunamiforce 1.00 – – –γwl rwl=1.5 1.00 – – –

rwl=2.0,2.5 1.00 – –H.H.W.L. 1.00 – –

γWRC UnitweightofRC 1.00 – – –γWNC UnitweightofNC 1.00 – – –γWSAND Unitweightoffillingsand 1.00 – – –γa Structuralanalysisfactor 1.00orover – – –

Bearingcapacityof

foundationground

γPH Tsunamiforce 1.00 – – –γq Surchargeonslicesegment 1.00γw ’ Weightofslicesegment 1.00γtanφ ’ Groundstrength:Tangentofangleofshear

resistance1.00

γc ’ Groundstrength:Cohesion 1.00γa Structuralanalysisfactor 1.00orover

*1:α:sensitivityfactor,μ/Xk:biasofaveragevalue(averagevalue/characteristicvalue),V:coefficientofvariation.*2:RC:reinforcedconcrete,NC:non-reinforcedconcrete.*3:Changeofwaterdepthmild/steep:Gradientofseabottom<1/30/Longerthan 1/30.*4:rwldenotestheratioofthehighesthighwaterlevel(H.H.W.L.)andmeanmonthly-highwaterlevel(H.W.L.).

(5)The tsunamiprotection breakwaters are frequently constructed in locationswhere thewater is deep. In thiscase,theheightofthebreakwaterbodyisalsolarge,andthestabilityduringactionofgroundmotionbecomes

–650–


aparticularproblem.Therefore,itispreferabletoexamineseismicresistancebyperformingseismicresponseanalysesconsideringthenonlinearityofthemoundmaterials.Inaddition,itisalsopreferabletoexaminethestability of themound during action of groundmotion. The performance verification of themound for thestabilityduringactionofgroundmotionisequivalenttothatforthecompositebreakwaters;3.1.4 Performance Verificationcanbeusedasareference.

6.5 Structural Details

(1)AnexperimentalstudybyTanimotoetal.1)hasconfirmedthatinthesituationwhereatsunamiflowsinthrougha narrowharbor entrance, the flowvelocitywill increase and there are produced strong vortices that exert asubstantial influence on the stability of the armor material of the submerged mound section of breakwater.Tsunamialsoexercisesstrongtractiveforcesonthebed,whicharesaidtobeevengreaterthanthosebystormsurges.Attention,therefore,mustbepaidinparticulartothereinforcementforthestabilityofthebreakwatersectionataharborentranceandtoscourpreventionworksforthefoundationground.

(2)Becausetherubblemoundbecomesthickerasthewaterbecomesdeeper,itisnecessarytopaycarefulattentiontothestabilityoftherubblemoundagainstwaveforcesandwavetransformationontheslopesurfaceoftherubblemound. Itwillalsobenecessary tomakeextra-bankingfor therubblemoundagainst largesettlementof therubblemoundbyitsownweight.

6.6 Tsunami Reduction Effect of Tsunami Protection BreakwatersRegarding theeffectof tsunamiprotectionbreakwaters,oscillationanalysisofOfunatoBay, IwatePrefecture, forboth states before and after the construction of the tsunami protection breakwaterwhenTokachi-okiEarthquakeTsunamiofMay1968occurred,wascarriedoutbasedonrecordsofthetidallevelsmeasuredinthebay2)Accordingtotheresults,thewaveheightamplificationratioM, amplitudeatbackofbay/amplitudeofincidentwaves,aftertheconstructionisreducedintheloworderoscillationfrequencywithalongperiodTwasreducedincomparisonwiththatbeforetheconstruction,asshowninFig. 6.4.1,confirmingthattsunamiprotectionbreakwatersdemonstrateatsunamireductioneffect.2)ThishasalsobeenverifiedbynumericalcalculationsbyItohetal.3)

0 10 20 30 40 50 60

1

2

3

4

5

6

Without breakwater

After constructionof breakwater

Nagasaki

Tide level observation stationTide level observation station

Tsunami protection breakwaterHosoura

Ofunato

Tide level observation station

N

Oscillation period T [min]

Wav

e he

ight

am

plifi

catio

n ra

tio M

Fig. 6.4.1 Effect of Tsunami Protection Breakwater (Case of Ofunato Bay)

References

1) TANIMOTO,K.,KatsutoshiKIMURAandKeijiMIYAZAKI:StudyonStabilityofSubmergedDikeattheOpeningSectionofTsunamiProtectionBreakwaters,Rept.ofPHRIVol.27No.4,pp.93-121,1988

2) Horikawa, K. and H. Nishimura: Performance of Tsunami breakwaters Proceedings of 16th Conference on CoastalEngineering,JSCE,pp.365-369,1969

3) ITO,Y.,katsutoshiTANIMOTOandTsutomuKIHARA:DigitalComputationontheEffectofBreakwatersagainstLong-periodWaves(4thReport)-OntheEffectofOfunatoTsunamiBreakwateragainsttheTsunamicausedbytheEarthquakeonMay16,1968.-,Rept.ofPHRIVol.7No.4,pp.55-83,1968


–651–

7 Sediment Control GroinsMinisterial OrdinancePerformance Requirements for Sediment Control Groins

Article 15 1TheperformancerequirementsforsedimentcontrolgroinsshallsatisfytherequirementsspecifiedbytheMinisterofLand,Infrastructure,TransportandTourismforthemitigationofsiltationinwaterwaysandbasinscausedbylittoraldriftthrougheffectivecontrolofsedimentmovement.

2Theprovisionsoftheitem(2)oftheparagraph1oftheprecedingarticleshallbeappliedcorrespondinglytotheperformancerequirementsforsedimentcontrolgroins.

Public NoticePerformance Criteria of Sediment Control Groins

Article 38 1TheprovisionsofArticle35or36shallbeappliedtotheperformancecriteriaofsedimentcontrolgroinswithmodificationsasnecessaryinconsiderationofthestructuraltype.

2 Inaddition to theprovisionsof theprecedingparagraph, theperformancecriteriaof sedimentcontrolgroinsshallbesuchthatthesefacilitiesarearrangedappropriatelysoastoenablecontroloflittoraldrift,inconsiderationoftheenvironmentalconditionsandotherstowhichthefacilitiesconcernedaresubjectedandhavethedimensionsnecessaryfortheirfunction.

[Commentary]

(1)PerformanceCriteriaforSedimentControlGroinsIntheperformanceverificationforsedimentcontrolgroins,appropriateconsiderationshallbegiventotheincreaseinearthpressureduetothesedimentationbylittoraldriftandeffectsduetorivercurrents.

[Technical Note]

7.1 General

(1)LayoutofSedimentControlGroins

① Sedimentcontrolgroinsshallbeappropriatelylocatedbyconsideringthecharacteristicsofsedimenttransport,soastoexercisetheexpectedfunctionoflongshoretransportcontrol.

② Ingeneral, thesedimentcontrolgroinson theupdriftsideof longshoresediment transport,shallbe locatedperpendicular to theshoreline in thesurfzoneandshallower,andindeeperwaters,shallbe locatedso thatlittoraldriftisdispersedtothesideoppositetheharborentrance.

③ Incaseswheresedimentcontrolgroinsareconstructedonthedowndriftsideoflongshoresedimenttransportinordertoprevententrainmentoflittoraldriftintotheharborfromtheshoreonthedowndriftsideoflongshoresedimenttransport,ingeneral,thegroinshallbeconstructedperpendiculartothecoastlineandshallalsohaveanappropriatelengthconsideringwavedirectionandwavetransformation.Provided,however,thatincaseswhereasedimentcontrolgroinalsofunctionsasabreakwater,anappropriatelayoutconsideringitsrequiredfunctionsasabreakwaterisnecessary.

④ Ifasedimentcontrolgroininrequiredinplacessuchasthevicinityofwaterwaysinsideaharbor,itshallbeconstructedinanappropriatelocationinconsiderationofthenaturalconditions.

(2)LayoutofUpdriftSideBreakwatersItispreferablethattheupdriftsidebreakwaterisextendedbeyondthesurfzoneinthedirectionperpendiculartotheshorelineinordertocausedepositionoflittoraldriftattheupdriftsideofthebreakwater(refertoFig. 7.1.1).When this extension part is short or slanted towards the downdrift side from the shoreline, the efficiency ofsedimentcatchmentattheupdriftsideisreducedandsedimentcaneasilymovealongthebreakwatertowardstheharborentrance.Whenthissectionisextendedwithaslantangletowardsthedowndriftsidefromtheshoreline,itcaneasilybecomethecauseoflocalscouringattheupdriftside.1)Intheareadeeperthanthebreakerline,thebreakwatershallbeslantedsothatitsimultaneouslystopswavesanddisperseslittoraldrifttowardtheupdriftsideoftheharborentrancewiththeaidofreflectedwavesorMach-stemwaves(refertoFig. 7.1.1).

–652–


Longshore sediment transport

Breaker line

Deposition

Contour lines

Reflected wavesReflected waves

Waves

Kd=1.0

Kd: Diffraction coefficient

Updrift side break water

Breakwater(Sediment control groin)

Downdrift side sediment control groin

Fig. 7.1.1 Conceptual Layout of Breakwater (Sediment Control Groin)

(3)PositionoftheDowndriftSideBreakwaterandConstructionTimeWhen the updrift side breakwater is extended beyond the extension line of the downdrift side breakwater,depositionwillstartatthedowndriftsideofthelatterbreakwater.Sandbarwillthenbeformedfromtheshoretowardtheharborentrance,anditwillcausebeacherosionat thefardowndriftshore.2) If thedowndriftsidebreakwater isextendedduringconstructionof theupdriftbreakwaterand theslant sectionof the latter isnotextended enough, remarkable local erosionmaybe caused at theharbor sideof thedowndrift breakwater, asshownFig. 7.1.2(a).Conversely,iftheextensionofthedowndriftbreakwaterisdelayed,itmaycausedepositionintheharboranderosionatthedowndriftshoreasshowninFig. 7.1.2(b).Verycarefulattentionshouldthereforebepaid to theextensionspeedofboth theupdriftanddowndrift sidebreakwaters,andcaremustbe taken tomaintaintheappropriatebalanceofextensions.

Kd=1.0

ErosionErosion

DepositionDepositionDepositionDeposition

ErosionErosion

(a) Case with rapid extension of thedowndrift-side breakwater

(b) Case with slow extension of the downdrift-side breakwater

Fig. 7.1.2 Construction Time of Downdrift Side Breakwater

(4)LengthofBreakwaterandWaterDepthatTipBecauselongshoresedimenttransportoccursmainlyinthesurfzone,itisnecessarytoextendthebreakwateroffshorebeyondthesurfzone.Insmallportswherethewaterdepthatthetipofthebreakwaterremainsinthesurfzoneduringstormyweather,itisdifficulttocompletelypreventlittoraldriftfromenteringtheport.AtmajorportsinJapan,therearemanycasesinwhichthewaterdepthatthetipofupdriftsidebreakwaterisapproximatelyequaltothemaximumdepthofthenavigationchannelsintheportconcerned.

(5)StructuralFormsofSedimentControlGroinBecause the required functionof a sediment controlgroin is to stop sediment transportfirmly, inprincipal asedimentcontrolgroinshouldhaveanimpermeablestructure.Whererubblestonesorconcreteblocksareusedtobuildasedimentcontrolgroinaroundtheshoreline,thecoreistobefilledwithquarryrunorsmallstonesofupto100to200kg;therearealsocaseswheretheharborsideofthesedimentcontrolgroiniscoveredwithimpermeablematerials such as sandmastic asphalt. In the following situations, it is preferable to adopt thestructureofwave-dissipatingtypes.

①Whenthereisalargeconcernaboutscouringbycurrents.

②Whenthereareconcernsofshoalingcausedbyreflectedwavesorofcausingobstructiontothenavigationofships.


–653–

7.2 Performance Verification

(1)CrownHeightofSedimentControlGroinAlthoughitispreferableforsedimentcontrolgroinsnottoallowovertoppingofwavestopreventtheinflowofsuspendedsediment,therearealsocaseswhereovertoppingispermittedduetostructuralconstrainsorbyreasonsofconstructioncosts.Thecrownheightshouldbedeterminedbytakingthefollowingintoconsiderations:

① SectionaroundshorelineItispreferablethatthecrownheightofthesectionaroundtheshorelineofsedimentcontrolgroinsbesufficientlyhighastopreventovertoppingbyrunning-upwaves.Becausesandcarriedbyrunupwavesmayovertopthecrestofthesectionaroundshorelineofthesedimentcontrolgroin,thecrestshouldbesufficientlyhigh.Itispreferabletoraisethecrownheightorextendthegroinitselftothelandwarddirection,inviewofconditionsafterconstruction.

② SectionslocatedshallowerthanthebreakerlinedepthThecrownelevationofthesedimentcontrolgroininthesectionslocatedshallowerthanthebreakerlinedepthmaybe0.6H1/3abovethemeanmonthly-highestwaterlevel(HWL),whereH1/3shouldbethesignificantwaveheightaroundthetipofsedimentcontrolgroin.

③ SectionslocateddeeperthanthebreakerlinedepthThecrownelevationofthesedimentcontrolgroininthesectionslocateddeeperthanthebreakerlinedepthshouldbeaheightthatisobtainedbyaddingacertainmargintothemeanmonthly-highestwaterlevel.Inthewaterdeeperthanthebreakerzone,thesuspendedsedimentisconcentratedneartheseabedandovertoppingwatercontainsalmostnosediment,andthereforeovertoppingmaybepermitted.

References

1) Tanaka, N: Transformation of sea bottom and beach near port constructed within the beach, Proceedings of AnnualConference,pp.1-46,1974

2) SATO,S.,NorioTANAKAandKatsuhiroSASAKI:TheCaseHistoryonVariationofSeaBottomTopographyCausedbytheConstructionWorksofKashimaHarbour,Rept.ofPHRIVol.13No.4,pp.3-78,1974

3) Nakase,A.,T.OkumuraandM.Sawaguchi:Easy-to-understandFoundationworks,KajimaPublishing,p.376、1981

–654–


8 SeawallsMinisterial OrdinancePerformance Requirements for Seawalls

Article 16 1Theperformancerequirementsforseawallsshallbeasspecifiedinthesubsequentitemsforthepurposeofprotectingthelandareabehindtheseawallinconsiderationofitsstructuretype.(1)SeawallsshallsatisfytherequirementsspecifiedbytheMinisterofLand,Infrastructure,Transportand

Tourismsoastoenableprotectionofthelandareabehindtheseawallconcernedfromwavesandstormsurges.

(2)Damageduetoselfweight,earthpressure,variablewaves,andLevel1earthquakegroundmotions,and/orotheractionsshallnotimpair thefunctionsoftheseawallconcernedandshallnotadverselyaffectitscontinueduse.

2Inadditiontotheprovisionsoftheprecedingparagraph,theperformancerequirementsforseawallsintheplacewherethereisariskofseriousimpactonhumanlives,property,and/orsocioeconomicactivitybythedamagetotheseawallconcernedshallincludethesubsequentitems,inconsiderationofthetypeofseawall.(1)Theperformancerequirementsforaseawallwhichisrequiredtoprotectthelandareabehindtheseawall

concernedfromtsunamisoraccidentalwavesshallbesuchthattheseawallsatisfytherequirementsspecifiedbytheMinisterofLand,Infrastructure,TransportandTourismsoastoenableprotectionofthelandareabehindtheseawallconcernedfromtsunamisoraccidentalwaves.

(2)Damageduetotsunamis,accidentalwaves,Level2earthquakegroundmotions,and/orotheractionsshallnothaveaseriousimpactonthestructuralstabilityoftheseawallconcerned,evenincaseswherethe functions of the seawall concerned are impaired. Provided, however, that for the performancerequirementsforaseawallwhichrequiresfurtherimprovementofitsperformanceduetoenvironmental,socialand/orotherconditions towhich theseawallconcerned is subjected, thedamagedue tosaidactions shallnot adverselyaffect the restoration throughminor repairworkof the functionsof theseawallconcerned.

Public NoticePerformance Criteria of Seawalls

Article 39 1TheprovisionsconcerningthestructuralstabilityinArticle49throughArticle52excludingtheprovisionsconcerningshipberthingandtractionbyshipsshallbeappliedwithmodificationsasnecessary to theperformancecriteriaofseawallsinconsiderationofthetypeofstructure.

2Inadditiontotheprovisionsoftheprecedingparagraph,theperformancecriteriaofseawallsshallbeasspecifiedinthesubsequentitems:(1)Theseawallshallbearrangedappropriatelysoastoenablecontrolofwaveovertoppinginconsideration

oftheenvironmentalconditionsandotherstowhichtheseawallsconcernedaresubjectedandshallhavethedimensionsnecessaryfortheirfunction.

(2)Underthevariableactionsituationinwhichthedominantactioniswaterpressure,theriskoflosingthestabilityduetoseepagefailureofthegroundshallbeequaltoorlessthanthethresholdlevel.

(3)Inthecaseofthestructurehavingaparapet,theriskofslidingandoverturningoftheparapetunderthevariableactionsituationinwhichthedominantactionsarevariablewavesandLevel1earthquakegroundmotionsshallbeequaltoorlessthanthethresholdlevel.

3Inadditiontotheprovisionsoftheprecedingtwoparagraphs,theperformancecriteriaoftheseawallsintheplacewherethereisariskofseriousimpactonhumanlives,property,orsocioeconomicactivitybythedamagetothefacilitiesconcernedshallbeasspecifiedinthesubsequentitems:(1)Seawallswhicharerequiredtoprotectthehinterlandfromtsunamisoraccidentalwavesshallhavethe

dimensionsasnecessaryforprotectionofthehinterlandfromtsunamisoraccidentalwaves.(2)Undertheaccidentalactionsituationinwhichthedominantactionsaretsunamis,accidentalwaves,or

Level2earthquakegroundmotions,thedegreeofdamageowingtothedominantactionsshallbeequaltoorlessthanthethresholdlevelcorrespondingtotheperformancerequirements.


–655–

[Commentary]

(1)PerformanceCriteriaforSeawalls①Commonperformancecriteriaforseawalls

ThesettingsinconnectionwiththeperformancecriteriaanddesignsituationsexcludingaccidentalsituationsforthestabilityofthefacilitiesofseawallsshallbeasshownintheAttached Table 21.Intheperformancecriteriaforseawalls,inadditiontotheseprovisions,thesettingsinconnectionwiththePublic Notice, Article 22, Item 3 (ScouringandSandWashingOut)andArticle 28 Performance Criteria of Armor Stones and Blocksshallapply,asnecessary,anddependingonthetypeofmemberscomprisingtheobjectiveseawall,thesettinginconnectionwithArticle 23through Article 27 shallalsoapply.

Attached Table 21 Settings for Performance Criteria and Design Situations (excluding accidental situations) of Stability of Facilities Common to Seawalls



Designsituation


Article

Paragraph

Item

Article

Paragraph


actionNon-

dominatingaction

16 1 2 39 2 2 Usability Variable Waterpressure Selfweight Seepagefailureofground

Limitvalueforseepagefailure

3 Variablewaves Selfweight,earthpressure,waterpressure

Slidingoroverturningofparapet*1)

LimitvalueforslidingLimitvalueforoverturning

Level1earthquakegroundmotion

Selfweight,earthpressure,waterpressure

LimitvalueforslidingLimitvalueforoverturning

*1):Limitedtostructureshavingparapets.

②Seawallsasfacilitiesagainstaccidentalincidents(a)Stabilityoffacilities(safety,restorability)1) Thesettingsinconnectionwiththeperformancecriteriaanddesignsituationslimitedtoaccidental

situationsof seawallsdesignedas facilities against accidental incidents shallbe as shown in theAttached Table 22.Inperformanceverificationofseawallsasfacilitiesagainstaccidentalincidents,amongthesettingsinconnectionwiththeperformancecriteriaanddesignsituationsfortheaccidentalsituationsofLevel2earthquakegroundmotion,tsunamis,andaccidentalwaves,valuesshallbesetappropriately corresponding to the structural type of the objective seawall and the performancerequirementsoftheobjectiveseawall. TheitemssafetyandrestorabilityarespecifiedintheperformancerequirementsintheAttached Table 22becausetheperformancerequirementswilldifferdependingonthefunctionsrequiredintheobjectiveseawalldesignedasfacilitiesagainstaccidentalincidents. Asperformancecriteriainconnectionwithaccidentalsituationsforseawallsdesignedasfacilitiesagainstaccidentalincidents,inadditiontotheseprovisions,thesettingsinconnectionwiththePublic Notice Article 22 Performance Criteria Common to Structural Members shallalsoapplyasnecessary.

Attached Table 22 Settings for Performance Criteria and Design Situations limited to Accidental Situations for Seawalls as Facilities against Accidental Incidents



Designsituation


Article

Paragraph

Item

Article

Paragraph


actionNon-

dominatingaction

16 1 2 39 3 2 Safety,restorability

Accidental Level2earthquakegroundmotion(Tsunami)(Accidentalwave)

Selfweight,earthpressure,waterpressure

Damage –

*1):Limitedtostructureshavingparapets.

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2) DegreeofdamageInsettingthelimitvalueofthedegreeofdamageforaccidentalsituationsinwhichthedominatingactionsareLevel2earthquakegroundmotion,tsunamis,andaccidentalwavesintheperformanceverificationsofseawallsasfacilitiesagainstaccidentalincidents,considerationshallnotbelimitedtothefunctionsoftheobjectiveseawall,butshallalsoincludecomprehensiveconsiderationsoftheconditionofimplementationofthesurroundingprotectivefacilitiesfortheharborandotherfacilitiesforprotectionofthehinterland,andsoftcountermeasuresrelatedtodisasterreductionanddisasterpreventionintheobjectiveregion.Inseawallsusedasfacilitiesagainstaccidentalincidentsinwhichrestorabilityisaperformancerequirement,appropriateconsiderationshallbegiventotheallowablerestorationperiodwhensettingthelimitvalueofthedegreeofdamage.

3) AccidentalsituationinwhichdominatingactionistsunamiIntheperformanceverificationsinconnectionwithtsunamis,incaseswheretheexpectedtsunamioccursasaresultofanearthquakewithahypocenterlocatedneartheobjectivefacilities,appropriateconsiderationshallbegiventothefactthatthefacilitieswillbeaffectedbytheactionofthegroundmotioncausedbytheobjectiveearthquakebefore theyareaffectedbytheactionof the tsunami.In otherwords, in caseswhere the dominating action is the accidental situation associatedwithtsunamis,itisnecessarytoconducttheperformanceverificationfortsunamisbasedonconsiderationoftheeffectscausedbytheactionofthegroundmotionwhichprecedesatsunami.ItshouldbenotedthatthegroundmotionwhichprecedesthetsunamiwhichisexpectedinthiscaseisnotnecessarilyidenticalwiththeLevel2earthquakegroundmotion.

References

1) ShoreprotectionfacilityTechnicalCommittee:Technicalstandardsandcommentaryforshoreprotectionfacilities,JapanPortAssociation,2004


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9 Training JettiesMinisterial OrdinancePerformance Requirements for Training Jetties

Article 17 1Theperformance requirements for training jetties shallbe such that the requirements specifiedby theMinisterofLand,Infrastructure,TransportandTourismaresatisfiedforthepreventionofclosureofarivermouthbylittoraldriftthrougheffectivecontrolofsedimenttransport.

2Theprovisionsoftheitem(2)oftheparagraph(1)ofArticle14shallbeappliedcorrespondinglytotheperformancerequirementsfortrainingjetties.

Public NoticePerformance Criteria of Training Jetties

Article 40 TheprovisionsofArticle38shallbeappliedtotheperformancecriteriaoftrainingjettieswithmodificationsasnecessary.

[Commentary]

(1)PerformanceCriteriaofTrainingJettiesThe settings in connectionwith thePublic Notice, Article 38 Performance Criteria of Sediment Control Groins shallbeappliedwiththenecessarymodificationstotheperformancecriteriaoftrainingjetties.Intheperformance verifications of training jetties, appropriate consideration shall be given to the increase of earthpressureduetosedimentationoflittoraldriftandtowavesandrivercurrents.

[Technical Note]

9.1 General

(1)LayoutofTrainingJettiesExamplesofthelayoutoftrainingjettiesinrelationtothedirectionoflongshoresedimenttransportareshowninFig. 9.1.1.1)Themostpreferableoneformaintainingthewaterdepthofrivermouthistoextendtwoparalleltraining jetties, because a single training jetty alone is not effective. Where two training jetties of differentlengthsareputinplace,usuallyitiseffectivetomakethetrainingjettyonthedowndriftsidelonger.Bendingtheupdrifttrainingjettytowardsthedowndriftsidewillpreventsedimentmovingintotheareabetweentwotrainingjettiesandmakethesedimenttransportedalongshorepasssmoothlytothedowndriftside.Foractualexamplesofrivermouthimprovement,refertothereference2).

(2)WaterDepthatTipofTrainingJetties

① Thewaterdepthatthetipofatrainingjettyshouldbeequaltoorgreaterthanthewaterdepthofthewaterwayinthevicinityofthetrainingjetty.

② Thetipofthetrainingjettyshouldbelocatedatequaltoorgreaterwaterdepththanthelimitingwavebreakerdepth.

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A narrow but deepgut is preserved

A narrow but deepgut is preserved

Longshoresediment transport





Grows shallow

Grows shallow

River mouth will movetowards the downdrift side

Fig. 9.1.1 Varieties of Training Jetty Layout 1)

9.2 Performance Verification Becausethetrainingjettyisgenerallylongerthangroinsandisexposedtointensivewaveactions,itisnecessarytoconsiderscouringatthetipandsidesofajetty.Inaddition,itshouldbeconsideredthattheriversideofthetrainingjettywillbesubjecttoscouringactionbytherivercurrent.

References

1) JSCE:HandbookofCivilEngineering,(Vol.2),pp.2268-2270,1974


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10 FloodgatesMinisterial OrdinancePerformance Requirements for Floodgates

Article 18 1Theperformancerequirementsforfloodgatesshallbeasspecifiedinthesubsequentitemsforthepurposeofprotectingthehinterlandofthefloodgatefrominundationandofdrainingunnecessaryinlandwater.(1)FloodgatesshallsatisfytherequirementsspecifiedbytheMinisterofLand,Infrastructure,Transport

andTourismforpreventionofoverflowduetostormsurges.(2)FloodgatesshallsatisfytherequirementsspecifiedbytheMinisterofLand,Infrastructure,Transport

andTourismforprotectionofthehinterlandfrominundationandfordrainageofunnecessaryinlandwater.

(3)Damagedue toselfweight,waterpressure,variablewaves,Level1earthquakegroundmotions,orotheractionsshallnotimpairthefunctionsofthefloodgateconcernedandnotaffectitscontinueduse.

2 Inaddition to theprovisionsof theprecedingparagraph, theperformance requirements forfloodgateswhichhaveariskofhavingaseriousimpactonhumanlives,property,and/orsocioeconomicactivitybythedamagetothefloodgateconcernedshallincludethesubsequentitemsinconsiderationofthetypeoffloodgate.(1)In the performance requirements for a floodgatewhich is required to protect the hinterland of the

floodgateconcernedfromtsunamisoraccidentalwaves,thefloodgateshallsatisfytherequirementsspecifiedbytheMinisterofLand,Infrastructure,TransportandTourismsoastoenableprotectionofthehinterlandofthefloodgateconcernedfromoverflowsbytsunamisoraccidentalwaves.

(2)Thedamageduetotsunamis,accidentalwaves,Level2earthquakegroundmotions,orotheractionsshallnothaveaserious impacton thestructuralstabilityof thefloodgateconcerned,evenincaseswhere the functions of the floodgate concerned are impaired. Provided, however, that as for theperformancerequirementsforfloodgateswhichrequirefurtherimprovementintheperformanceduetoenvironmental,social,orotherconditionstowhichthefloodgatesconcernedaresubjected,thedamageduetosaidactionsshallnotaffecttherestorationthroughminorrepairworksofthefunctionsofthefloodgateconcerned.

Public NoticePerformance Criteria of Floodgates

Article 41 1Theperformancecriteriaoffloodgatesshallbeasspecifiedinthesubsequentitems:(1)Floodgatesshallbelocatedappropriatelysoastoenableprotectionofthelandbehindthefacilitiesfrom

inundationanddrainageofunnecessarywateraccumulatedthereinconsiderationoftheenvironmentalconditionsandothers towhichthefacilitiesconcernedaresubjectedandshallhavethedimensionsnecessaryfortheirfunction.

(2)Floodgatesshallhavethedimensionsnecessaryinconsiderationofstormsurges,waves,andtsunamis.(3)Underthepermanentactionsituationinwhichthedominantactionisselfweight,theriskofimpairing

theintegrityofthemembersandlosingthestructuralstabilityshallbeequaltoorlessthanthethresholdlevel.

(4)Floodgates shall satisfy the following standards under the variable action situation in which thedominantactioniswaterpressure:(a) The riskof impairing the integrityof the structuralmembers shallbeequal toor less than the threshold

level.

(b)Theriskoflosingthestructuralstabilityduetoseepagefailureofthegroundshallbeequaltoorlessthanthethresholdlevel.

(5)Floodgates shall satisfy the following standards under the variable action situation in which thedominantactionsarevariablewavesandLevel1earthquakegroundmotions:

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a) Theriskofimpairingtheintegrityofthestructuralmembersshallbeequaltoorlessthanthethresholdlevel.

b) Theriskoflosingthestabilityoffloodgatesystemshallbeequaltoorlessthanthethresholdlevel.2Inadditiontotheprovisionsoftheprecedingparagraph,theperformancecriteriaoffloodgatesinwhichthereisariskofseriousimpactonhumanlives,property,orsocioeconomicactivitybythedamagetothefacilitiesconcernedshallbeasspecifiedinthesubsequentitems:(1)Floodgateswhicharerequiredtoprotectthehinterlandfromtsunamisoraccidentalwavesshallhave

thedimensionnecessarytocontroloverflows.(2)Undertheaccidentalactionsituationinwhichthedominantactionsaretsunamis,accidentalwaves,or

Level2earthquakegroundmotions,thedegreeofdamageowingtothedominantactionsshallbeequaltoorlessthanthethresholdlevelcorrespondingtotheperformancerequirements.

[Technical Note]

(1)LayoutandDimensionsofFloodgates

① LayoutIn setting the layout in the performance verifications of floodgates, it is necessary to give appropriateconsiderationtoinstallationinapositionwherethewatergatecandemonstrateitsfullwatercollectingcapacity,andtoavoidinginstallationinpositionswheresedimentswilltendtoaccumulateduetotheeffectsofwind,waves,andwatercurrents.

② StructureIn setting the structure of the transitional part of gate in the performance verifications of floodgates, it isnecessary to give appropriate consideration to the quality, shape, anddimensions of thematerials and to awatertightstructuresoastosecuretherequiredwater-tightness.

③ Cross-sectionaldimensionsInsettingtheheightandotherdimensionsintheperformanceverificationsoffloodgates,itisnecessarytogiveappropriateconsiderationtothedewateringcapacityoftheobjectivefloodgate,theeffectsoflittoraldriftandsettlementoftheground,thewaterlevelsinsideandoutsidetheobjectivewatergateandinthesurroundingground.Infloodgateswhichallowpassageofships,whensettingtheheight,appropriateconsiderationshallbegiventosettingaheightwhichwillnotimpedethepassageofships.

④ AncillaryequipmentIntheperformanceverificationsoffloodgates,itisnecessarytoexaminetheinstallationofancillaryequipmentforuseinmaintenancecontrol,suchascontrolbridges,stairs,handrails,asnecessary,soastoenablesafeandsmoothoperationandmaintenancecontrolofthegate.

References

1) ShoreProtectionFacilityTechnicalCommittee:Technicalstandardsandcommentaryforshoreprotectionfacilities,JapanPortAssociation,2004


–661–

11 Locks Ministerial OrdinancePerformance Requirements for Locks

Article 19 1Theperformance requirements for locks shallbeas specifiedby theMinisterofLand, Infrastructure,TransportandTourismforthepurposeofenablingthesafeandsmoothnavigationofshipsbetweenthewaterareashavingdifferentwaterlevels.

2Theprovisionsoftheitems(1)and(3)oftheparagraph(1)andtheparagraph(2)oftheprecedingarticleshallbeappliedcorrespondinglytotheperformancerequirementsforlocks.

Public NoticePerformance Criteria of Locks

Article 42 1Theprovisionsoftheprecedingarticleshallbeappliedtolockswithmodificationsasnecessary.2Inadditiontotheprovisionsoftheprecedingparagraph,theperformancecriteriaoflocksshallbesuchthatthelocksarelocatedappropriatelysoastoenableshipstonavigatesafelyandsmoothlyinconsiderationoftheenvironmentalconditionstowhichthefacilitiesconcernedaresubjected,theutilizationconditions,andothers,andthelockshavethedimensionsnecessaryfortheirfunction.

[Commentary]

(1)PerformanceCriteriaforLocks① Safeandsmoothnavigationofships(usability)(a) Thespecificationsoflocksshallcomprisethestructureandcross-sectionaldimensionsofthelockandthe

ancillary equipment. In setting the layout and dimensions in the performance verifications of locks, thesettings in connectionwith thePublic Notice, Article 41 Performance Criteria of Floodgates shall beapplied;inaddition,appropriateconsiderationshallbegiventothenecessaryconditionsforsafeandsmoothnavigationofships.

(b)Cross-sectionaldimensionsIntheperformanceverificationsoflocks,waterdepth,width,andlengthshallbesetappropriatelyconsidering the respective clearances, based on appropriate consideration of the effects of thedimensionsandmotionofthedesignshipandtheexpectedtrafficvolume.

(c)AncillaryequipmentIn theperformanceverificationsof locks, the layoutof the ancillary equipment formaintenancecontrol,includingemergencyequipment,lightingequipment,power-relatedequipment,monitoringand instrumentation equipment, and maintenance and control equipment shall be examined, asnecessary,inordertosecuresafeandsmoothoperationoftheobjectivelock.

[Technical Note]

(1)General

① ThenamesoftherespectivepartsoflocksshallbeasshowninFig. 11.1.

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Gate recess Effective widthof gate chamberEffective widthof gate chamber

Effective lengthof lock chamberEffective lengthof lock chamber

Effective widthof lock chamberEffective widthof lock chamber

Front gate chamber Rear gate chamber

Lock chamber

Plane view

Side viewSill height

Lock gate

Fig. 11.1 Names of Respective Parts of Lock

② Installationpositionoflocks

(a) Therearecasesinwhichlocksimposeconstraintsonthefunctionsofthesurroundingharbor,forexample,bylimitingtheareaofbasins,landdesignatedforextensionofmooringfacilities,andhinderothernavigatingshipsdependingonwhethertheinstallationpositionofthelockisappropriateornot.Thenaturalconditionsattheinstallationpositionalsohavealargeeffectonconstructioncosts.Accordingly,itispreferabletouseduecareinselectingthepositionsoflocks.

(b)Itispreferablethatinstallationoflocksonsoftgroundbeavoidedwheneverpossible.However,incaseswhereinstallationonsoftgroundisunavoidable,adequatecountermeasuresshouldbetakenforunevensettlement.Becausethefunctionsofthelockwilldeclinebysettlementofthegateatlocationswheregroundsettlementoccurs,itispreferabletoraisethecrownheightinadvanceinsuchcases.

(c) Because ship’s ingress and egressmaybecomedifficult owing to the factors such aswinds,waves, tidalcurrents,andlittoraldrift,itisoptimaltochooseacalmwaterareaforthelocklocation.Incaseswherethewaterisnotcalm,breakwatersshouldbeconstructed,ortrainingjettiesorguidingjettiesshouldbeextendedtomakethewaterzonecalminthevicinityofthelock.

(d)Thesizeandnumberofshipsthatwillpassthroughthelockarealsofactorsintheselectionofthelocation.Thatis,thelockmustbelocatedatthesitewhereasufficientlywideareaofwatercanbesecuredforanchorageandturningbasinforusebywaitingships.

(e) In addition to the above, the lock’s location must be selected with adequate consideration given to theconditionsoflandusageortrafficconditionsoftheinlandarea.

③ Sizeandshapeoflocks

(a) Thescaleofthelockchambercangenerallybesetbasedonequation (11.1).Inthiscase,appropriatevaluesshallbesetconsideringthekeelclearance,beamclearance,andlengthclearancementionedinthefollowingitems,consideringthemotionoftrafficships.

Effectivewaterdepth=Draftofshippassingthroughlock+KeelclearanceEffectivewidth=BeamofshipspassingthroughlockxNumberofshipsinparallelxBeamclearance (11.1)Effectivelength=LengthofshipspassingthroughlockxNumberofshipsinonelinexLengthclearance

(b)Generally,theclearancesforthevariousdimensionsforlocksdependupontheshipsize.Fukuda,however,hasproposedthefollowingvaluesforlocksusedbysmallships:

Clearanceforeffectivewaterdepth:0.2–1.0mClearanceforeffectivewidth: 0.2–1.2mClearanceforeffectivelength: 3–10m


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(2)PerformanceVerification

① LockdoorsThedoorsoflocksshouldhaveastructurewhichmakesitpossibletosecuretheassumeddifferenceinwaterlevelsandtherequiredstabilityagainstactionsduetowaves,andshouldalsohaveastructurewhichsatisfiesthefollowingrequirements.

1) Itshallconsiderthescaleofthelock,timerequiredforopeningandclosing.2) Itshallbeeasytoinspectthemachinerysectionandothermovingparts.3) Itshallconsiderwearandpreventionofcorrosionofmembers.

② LockchamberThelockchambershallhaveastructureappropriatetomeettheconditionssuchasthefoundationcondition,waterleveldifferencebetweeninsideandoutsidethelockchamber,thedimensionsandnumberofshipstobeaccommodated,andthequantityofwaterchanginganddischargingofthelockchamber.

References

1) Nishihata,I.:DesignofWaterGateandLockGate,OhomPublishing,20042) Fukuda,H.:Lock,Jyo-ritsuPublishing,19553) Planning Division, The third Port Construction Bureau, Ministry of Transport: Storm surge countermeasure works (

ImprovementofLockgate)atthecoastofAmagasaki,NishinomiyaandAshiya,DisasterPreventioninPortsandHarbours,AssociationofdisasterPreventioninPortsandcoast,pp.41-45,1990

–664–


12 RevetmentsMinisterial OrdinancePerformance Requirements for Revetments

Article 20 1The provisions of Article 16 shall be applied correspondingly to the performance requirements forrevetments.

2Inadditiontotheprovisionsoftheprecedingparagraph,theperformancerequirementsforrevetmentstobeutilizedbyanunspecified largenumberofpeopleshallsatisfy therequirementsspecifiedby theMinisterofLand, Infrastructure,TransportandTourismsoas to secure the safetyof theusersof therevetmentconcerned.

12.1 Common Items for RevetmentsPublic NoticePerformance Criteria of Revetments

Article 43 1TheprovisionsofArticle39shallbeappliedtotheperformancecriteriaforrevetmentswithmodificationsasnecessary.

2 In addition to the provisions of the preceding paragraph, the performance criteria for the revetmentswhichareutilizedbyanunspecifiedlargenumberofpeopleshallbesuchthattherevetmentshavethedimensionsnecessarytosecure thesafetyofusers inconsiderationof theenvironmentalconditions towhichthefacilitiesconcernedaresubjected,andtheutilizationconditions,andothers.

[Commentary]

(1)PerformanceCriteriaofRevetments①Amenity-orientedrevetments(usability)(a)In setting the structure and dimensions in the performance verifications of amenity-oriented

revetments,considerationshallbegiventotheeffectsofwaveovertoppingandspray,preventionof slippingand fallingand falling into thewaterofusers, and smooth implementationof rescueactivitiesforuserswhohavefallenintothewater.Ancillaryequipmentsuchasfencestopreventfallingshallbeinstalledappropriately.

[Technical Note]


(1) Incaseswhereareclamationrevetmentisbuiltadjoiningtotheexistinglandarea,constructionoftherevetmentmaycausethegroundwaterleveltoriseormayresultindeteriorationofgroundwaterquality.Adequateattentionshouldbepaidtotheseaspectswhenstudyingthereclamationlayoutplanandrevetmentstructure.Itispreferabletoinvestigatetheconditionsofthegroundwaterinthelandareainadvance.Inaddition,incaseswhereitisthoughtthat reclamation revetment constructionwill causedeteriorationof thegroundwater quality, countermeasuressuchasconstructionofawatertightwallmustbeconsideredinordertoinsulatethegroundwaterofthelandfromthereclaimedarea.

(2)Inthecaseofreclamationwherealargewaterareaisenclosedbyrevetments,theopeningbecomessmallerwiththeprogressofrevetmentconstruction,andaconsiderablerapidflowoccursatclosingsectionsduetothedifferenceofwater levelsbetween the insideandoutsideof revetments. Therefore,carefulconsideration is required forstructureofrevetmentsatthefinalclosingsection,whichshouldhaveenoughstabilityagainsttheexpectedflowspeed. Theflowvelocityatclosingsectionsiscontrolledbythewaterareabeingclosed,thecross-sectionalareaoftheclosingsection,theaveragewaterdepthandthedifferenceintidallevels.Inclosingsections,itispreferablethatgroundhardeningworkbeconductedatalocationwithgoodgroundbeforetheflowvelocityincreasesasworkprogresses.Dependingontheflowvelocityattheclosingsection,therearealsocasesinwhichasubmergedweirorbroad-crestedweirisused.


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12.1.2 Actions

(1)For the ground conditions of landfill soil, Part II, Chapter 3 Geotechnical Conditions can be used as areference.

(2)Foractionsduetogroundmotion,Part II, Chapter 4 Earthquakescanbeusedasareference.

(3)Fordynamicwaterpressure,Part II, Chapter 5, 2.2 Dynamic Water Pressure canbeusedasareference.

(4)As thewater level in reclaimed areas, twowater levels are generally set, these being thewater level in thereclaimedareaandtheresidualwaterlevel.Thewaterlevelinthereclaimedareaisusedinseepagecalculationsandtheperformanceverificationofwastewatertreatmentfacilities.Theresidualwaterlevelisthewaterlevelimmediatelybehindtherevetmentandisusedinexaminationofthestabilityoftherevetment.Provided,however,thatincaseswherethewaterlevelatpositionsneartherevetmentishigherthantheresidualwaterlevel,thedangerofcircularslipfailuremaybeunderestimatediftheresidualwaterlevelisusedintheexaminationofcircularslipfailure.Insuchcases,itisnecessarytoconducttheexaminationofthestabilityoftherevetmentforthewaterlevelinthereclaimedarea.

①WaterlevelinsidereclamationThewater level inside the reclamation area should be established by considering the stability of revetmentbothduringtheconstructionandaftercompletion,andtheinfluenceonthesurroundingwater.Regardingtheinfluenceonthesurroundingwaters,particularcautionshouldbepaidinconnectionwithovertoppingflowsduetowavesgeneratedinsiderevetmentsduringconstruction.Ifthewaterlevelinsidethereclamationareaisexcessivelyhighincomparisonwiththewaterlevelatthefrontoftherevetment,thewaterdischargeofpollutedwaterfromtherevetmentandfoundationgroundmayincrease;therefore,cautionisnecessary.Furthermore,attentionshallalsobepaidtothefactthatthewaterlevelinsidethereclaimedareawillinfluencethecostofconstructionof the revetment and the construction andmaintenancecontrol costsofwastewater treatmentfacilities.

② Residualwaterlevel

(a) Forreclamationrevetments,thestructureswithlowpermeabilityareoftenusedtoreducetotheseepageofcontaminatedwaterthroughrevetments.Forthisreason,theresidualwaterlevelbehindthemisgenerallyhigherthanthatbehindquaywallsorordinaryrevetments.

(b)Reviewingexamplesofthepastconstruction,inreclamationrevetmentswithgravity-typestructures,therearemore cases inwhich permeability is reduced by increasing the layer thickness of the levee-wideningearthorthebackfillingsandthanbyreducingthepermeabilityoftherevetmentbodyitself.Accordingly,inrevetmentsofthistype,theresidualwaterlevelusedintheperformanceverificationoftherevetmentbodyshouldbethesameasinordinarygravity-typerevetments,asthewaterleveljustbehindtherevetmentbodyshowsbehaviorsimilartothatinordinarygravity-typerevetments.

(c) For reclamationrevetmentsusingasheetpile, thereareexampleswheregroutmaterial ispoured into thesheetpilejointoradoublesheetpilestructureisusedtoincreasethewatertightness.Forthesecases,theresidualwaterlevelbehindthereclamationrevetmenttendstobehigherthanthatbehindtheordinarysheetpilequaywalls.

(5)Incaseofreclamationusingsuctiondredgers,therearecasesinwhichsuspendedsoftsoilconcentratesbehindtherevetmentandgreater-than-expectedearthpressureactsontherevetmentbody,andcasesinwhichtheactionofthewaterpressureatthebacksideofthestructureextendsasfarasthecrestoftherevetment.Therefore,itisnecessarytogiveadequateconsiderationtothesephenomenaintheperformanceverifications.

12.1.3 Performance Verification

(1) Intheperformanceverificationsofrevetments,thefollowingitemsshallgenerallybeexamined.

① Thecrownheightshallbetheheighttoenablepreservationanduseofthereclaimedlandunaffectedbywavesandstormsurges.

② Stabilityagainsttheactionsofwaves,earthpressure,etc.shallbesecured.

③Thestructureshallpreventleakageofthelandfillsoil.

④ Considerationshallbegiventotheeffectonsurroundingwaterareas,includingpreventionofoutflowofturbidwaterduringreclamationwork.

⑤ Inamenity-orientedrevetments,safeandpleasantuseofthestructurebyusersshallbepossible.

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(2)SettingofCrownHeight

① Forrevetments,anappropriatecrownheightshallbesetconsideringthewaveovertoppingquantity,tidallevelathightidesoastoenablepreservationofthelandfillbehindtherevetmentandnothinderuseoftherevetmentorthelandbehindit.

② Insettingthecrownheightofrevetments,thefollowingmethod1)canbeused.

(a) Therequiredcrownheighthdabovethedesignhighwaterleveloftherevetmentcanbesetasfollows,usingtherequiredcrownheighthcabovethewaterlevelcorrespondingtotheimportanceofthehinterland,ortherequiredcrownheighthc'consideringgroundmotionandthecrestsettlementdsduetoconsolidationobtainedfromthegroundconditions.

(12.1.1)

(b)Therequiredcrownheighthcabovethewaterlevelinequation (12.1.2)shallbeavalueobtainedbyaddingaheightallowancetothecalculatedcrownheightforthedesignwaveatthedesignhighwaterleveloftherevetment.TherequiredcrownheighthcabovethewaterlevelcanbecalculatedbysettingtheexceedenceprobabilityPforthepermissiblewaveovertoppingrate.TheexceedenceprobabilityPforthepermissiblewaveovertoppingratecanbecalculatedusingequation (12.1.2).Forthemeanvalueandthestandarddeviationofhc/hcd,1.00and0.15canbeused,respectively.

(12.1.2)

Provided,however,that

where P :exceedenceprobabilityofpermissiblewaveovertoppingrate hc :requiredcrownheightabovewaterlevel(m) hcd :calculatedcrownheightfordesignwaveatdesignhighwaterlevelofrevetment(m)

ζ : standarddeviationofln(hc/hcd);givenby

λ : meanvalueofln(hc/hcd);givenby

μ :meanvalueofhc/hcd(=1.00canbeassumed) σ :standarddeviationofhc/hcd(=0.15canbeassumed)

Equation(12.1.2)isshowngraphicallyinFig. 12.1.1.Forexample,assumingtheexceedenceprobabilityofthepermissiblewaveovertoppingrateis0.01,therequiredcrownheighthcabovethewaterlevel,whichisobtainedbyaddingaheightallowancetothecalculatedcrownheighthcd,isgivenas1.40timesthecalculatedcrownheighthcd.


–667–

0.0001

0.001

0.01

0.1

1

hc / hcd

Exce

eden

ce p

roba

bilit

y

1.00 1.15 1.45 1.601.30 1.75 1.90

Fig. 12.1.1 Relationship of Exceedence Probability of Permissible Wave Overtopping Rate to hc/hcd

(Required Crown height above Water Level / Calculated Crown height)

(3)Inorder to estimate thequantity of seepageof pollutedwater into the sea from reclamation revetments, it isnecessarytoperformananalysisofseepageflows.Ingeneral,Darcy’slawcanbeappliedtoseepageflowanalysis.However,aswillbediscussedbelow,thecrosssectionofarevetmentconsistsofdifferentmaterials,includingsheetpilesandconcretemembers,andbackfillingsand.Furthermore,permeabilityofsheetpileswilldifferatthejointsandinthesheetpilesthemselves.Forthisreason,therearecasesinwhichDarcy’slawcannotbeapplied. Inanalysisofseepageflowsinthiscase,itisrealistictotreatthecrosssectionoftherevetmentasastructurecomprisingmaterialstowhichDarcy’slawcanbeapplied.Therefore,itisnecessarytoconvertthecoefficientofpermeabilityandthewallwidth,applyingingenuityinordertoapplyDarcy’slawinanapproximatemanner. Inseepageflowanalysis,thescopeofanalysisextendstothepointwherethewaterlevelwithinthereclaimedareacanbeconsidereduniform.However,analysiscanbeperformedbysettingthescopecorrespondingtotherequiredaccuracy,consideringthestructureoftherevetmentbody,andconditionofbackfillingsand.Provided,however,thatcautionisnecessarywhenthepermeabilityofthelandfillsoildepositedinthereclaimedareaisitselflow,asthewaterlevelwithinthereclaimedareawillhaveasteepgradientinthelandfillsoil.

① Permeabilityofsteelsheetpilestructures

(a) The permeability of steel sheet pile structures cannot be derived fromDarcy’s law. However, it can beappliedbyusinganappropriateequivalentwidthandtheequivalentcoefficientofpermeabilityforthatwidth.Inaddition,becauseitcannotbeassuredthata laboratorytestcouldreproducethejointconditionsof theprotorypestructureinproperscale,itispreferabletousethevaluesmeasuredin-situ.

(b)Reference11) isavailableconcerningthepermeabilityofsteelsheetpile-typestructures. Itdescribes theresultofanalysestakingintoaccountthein-situmeasurementsonresidualwaterlevelsatfiveprojectsites.Intheanalyses,itwasassumedthatthesheetpilewallbelowtheseabedareimpermeableandthepartofwallabovetheseabedisequivalenttothepermeablelayerof1mthicktowhichDarcy’slawcanbeapplied.Theresultsobtainedfor thecoefficientofpermeability,equivalentcoefficientofpermeability,were in therangeof1x10-5–3x10-5cm/s.Theresultsofthesimilaranalysiscarriedoutfortwoexamplesofsteelpipepile-typequaywallwithdiameterofapproximately80cmyieldedavalueof6x10-5cm/s.Thecoefficientofpermeabilityforbackfillingmaterialoftheforegoingsurveyswasintherangeof10-2–10-3cm/s.

(c) Thepermeabilityofsheetpilejointhasthefollowingcharacteristics:Incaseswithoutbackfillingmaterial, thesheetpile joint issimilar innature toanarroworificeofabruptsectionalreduction,andcanbeexpressedinequation(12.1.3)withtheconstantn =0.512),13)

(12.1.3)where

q :flowrateperunitjointlength(cm3/s/cm) h :differenceinthewaterlevelbetweenthefrontandtherearofthesheetpile(cm) K,n :constant

Incaseswithbackfillingmaterial,thepropertyofthebackfillingmaterialgreatlyaffectsthequantityofseepagethroughthejoint.Inthevicinityofthebackfillingmaterialbehindthesheetpilejoint,thereareareasatwhichDarcy’slawcannotbeapplied.Therehasbeenanefforttoevaluatethepermeabilityasacompositejoint that includes a certain thickness of backfill and sheet pile joint. This idea is effective for seepage

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analysis.Shojietal.14)proposedanempiricalequationbasedonthecomprehensivetestsconsideringboththedifferenceinthedegreeoftensileforceinthejointandconditionswithorwithoutsandfilling.Fromtheresultsofthetests,forthecasethatthereisbackfillingandjointsarefilledwithsand,itwasfoundthattheconstantn couldbegivenanapproximatevalueof1.0andtheK valuerepresentingtheresultsofthetestswasderived.

② Permeabilityoffoundationground

(a) PermeabilityofnaturalgroundThepermeabilityofthenaturalgroundasawholecanbeevaluatedusingthecoefficientsofpermeabilityforeachsoillayercomprisingthenaturalground.Incalculatingthecoefficientsofpermeabilityforeachsoillayer,Part II, Chapter 3, 2.2.3 Hydraulic Conductivity of Soil canbeusedasareference.Ingroundwhichwas formedbynatural sedimentation, thecoefficientofpermeabilitydisplaysdirectionality, and inmanycases,thecoefficientofpermeabilityislargerinthehorizontaldirectionthanintheverticaldirection.

(b)PermeabilityofsoilimprovementsectionsIncaseswheresoilimprovementistobecarriedoutaspartofconstructionofareclamationrevetment,inadditiontoevaluationofthepermeabilityofthenaturalground,itisalsonecessarytoexaminethechangesinpermeabilityduetothesoilimprovement.

(c) Incasethatthefoundationismadeofrocks,carefulinvestigationsandconsiderationofpermeabilityshouldberequired,becausetherockfoundationmaycontaincracksorfissureswhichgoverntherateofseepage16)


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12.2 Revetments with Amenity Function Ministerial OrdinancePerformance Requirements for Revetments

Article 202Inadditionto theprovisionsof theprecedingparagraph, theperformancerequirementsforrevetmentstobeutilizedbyanunspecified largenumberofpeopleshallsatisfy therequirementsspecifiedby theMinisterofLand, Infrastructure,TransportandTourismsoas to secure the safetyof theusersof therevetmentconcerned.

Public NoticePerformance Criteria of Revetments

Article 432In addition to the provisions of the preceding paragraph, the performance criteria for the revetmentswhichareutilizedbyanunspecifiedlargenumberofpeopleshallbesuchthattherevetmentshavethedimensionsnecessarytosecure thesafetyofusers inconsiderationof theenvironmentalconditions towhichthefacilitiesconcernedaresubjected,andtheutilizationconditions,andothers.

[Technical Note]

(1) Inamenity-orientedrevetments,thecrosssectionoftherevetmentshallbesetconsideringthedangerofusersfallingintothesea,andancillaryfacilitiessuchasfencestopreventfallingshallbeprovidedappropriately,asnecessary.

(2)Infacilitieswherewaveovertoppingcanbeexpectedtoreachpartswherepeoplenormallywalkduringevenhighwaveconditions,itisnecessarytoensuregeneralpublicknowledgeofthedangerbyappropriatemeanssuchassigns.

(3)Whenfacilitiesareusedbyelderlypersons,andpersonswithphysicaldisabilities,effortsmustbemadetoenablesafemovementofwheelchairswhendesigningpassagesontherevetment,thewidthandgradientofslopes.

References

1) Nagao,T.,K.FujimuraandY.Moriya2) Shibata,K.,H.UedaandK.Ohori:StudyontheDimensionsofEmbankmentandSeawall,TechnicalNoteofPHRINo.448,

19833) Sekimoto,T.,Y.MoriyaandT.Nagao:Estimationmethodforsettlementrateofslopingseawallsbasedonovertoppingrate,

ProceedingsofOffshoreDevelopment,JSCE,Vol.20,pp.113-118,20044) Nagao, T., K. Fujimura and Y. Moriya: Study on examination of performance of sea walls, Proceedings of Offshore

Development,Vol.20,pp.101-106,20045) Iai,S.,Y.MatsunagaandT.Kameoka:ParameterIdentificationforaCyclicMobilityModel,Rept.ofPHRIVol.29,No.4,

pp.27-56,19906) Higashijima,Y.,K.Fujita,K.Kazui, S. Iai,T. Sugano andM.Kitamura:Development ofChart-sype earthquake proof

Inspectionsystemforcoastalfacilities,Proceedingsof31stSimposiumonOffshoreDevelopment,JSCE,20067) JapanInstituteofConstructionEngineering:Analyticalmethodfordeformationofriverdikesduringearthquake,20028) FLIPStudyGroup:ReportofPrecisionImprovementWorkingGroup2003,20049) FLIPStudyGroup:ReportofWorkingGroupfortheexaminationofsheardeformationoflocks2004,200510) KobeTechnicalsurveyoffice,KinkiDstrictDevelopmentBureau,MinistryofLand,InfrastructureandTransport:Guideline

forChart-sypeearthquakeproofInspectionsystemforcoastalfacilities,200511) Furudoi,M.andT.Katayama:Fieldobservationofresidualwaterlevel,TechnicalNoteofPHRINo.115,197112) Kubo,K.andM.Murakami:Anexperimentonwatersealingperformanceofsteelsheetpilewall,SoilandFoundation,Vol.

11,No.2,196313) Yamamura,K,T.Fujiyama,M.InutukaandK.Futama:Experimentonwatersealingperformanceofsteelsheetpilewall,

ReportofPublicWorksResearchInstitute,Vol.123No.3,196414) Syouji,Y.,M.KumetaandY.Tomita:ExperimentsonSeepagethroughInterlockingJointsofSheetPile,Rept.ofPHRIVol.

21,No.4,pp.41-82,198215) NipponSteelCorporation:Reportofwatertightnesstestofsteelsheetpiles,196916) RockEngineeringforCivilEngineers.GihodoPublishing,pp.238-254,1975

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17) TechnicalCommitteeforCoastalprotectionfacilities:Technicalstandardsandcommentaryofcoastalprotectionfacilities,JapanPortAssociation,2004

18) CoastalDevelopmentInstituteofTechnology:TechnicalManualforPortenvironmentupgrading,199119) JSCEEdition:Landscapedesignofportsandharbours,Giho-doPublishing,199120) Transport EconomyResearchCenter:Guideline of the facilities for elderly and handicapped people in public transport

terminal,1994


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13 Coastal DikesMinisterial OrdinancePerformance Requirements for Coastal Dikes

Article 21 TheprovisionsofArticle16shallbeappliedcorrespondinglytotheperformancerequirementsforcoastaldikes.

Public NoticePerformance Criteria of Coastal Dikes

Article 44 TheprovisionsofArticle39shallbeappliedtotheperformancecriteriaforcoastaldikeswithmodificationsasnecessary.

References

1) TechnicalCommitteeforCoastalProtectionFacilities:Technicalstandardsandcomment\aryofcoastalprotectionfacilities,JapanPortAssociation,pp.3-19-3-60,2004

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14 GroinsMinisterial OrdinancePerformance Requirements for Groins

Article 22 1TheperformancerequirementsforgroinsshallbeasspecifiedbytheMinisterofLand,Infrastructure,TransportandTourismforthepurposeofmitigatingtheinfluenceoflittoraldriftthrougheffectivecontrolofsedimenttransport.

2Theprovisionsoftheitem(2)oftheparagraph(1)ofArticle14shallbeappliedcorrespondinglytotheperformancerequirementsforgroins.

Public NoticePerformance Criteria of Groins

Article 45 TheprovisionsofArticle38shallbeappliedto theperformancecriteriaofgroinswithmodificationsasnecessary.

[Commentary]

(1)PerformanceCriteriaofGroins①Applicationwithnecessarymodificationsofperformancecriteriaofsedimentcontrolgroins(a) Settings in connectionwith thePublic Notice, Article 38 Performance Criteria for Sediment Control

Groins shall be applied with the necessary modifications to the performance criteria of groins. In theperformanceverificationsofgroins,appropriateconsiderationshallbegiventotheeffectofincreasedearthpressureduetoaccumulationoflittoraldrift,asnecessary,andappropriateconsiderationshallalsobegiventotheeffectsofwavesandrivercurrents.

(b)Controloflittoraldrift(usability)Inthelayoutofgroins,inadditiontothepositionswheregroinsareinstalled,theirdirectionandthemutualspacingbetweengroinsshallbeconsidered. In thedimensions, thestructure,crownheight, crestwidth, and length shall be considered. In setting the layout anddimensions in theperformanceverificationsof groins, appropriate consideration shall begiven to thepredominantdirectionofwavesandwatercurrents,topography,expectedconditionsofuseoftheobjectivegroin,andtheimpactonthenaturalenvironment,etc.sothatthefacilitiescandemonstratetheirrequiredfunctionofcontrollinglittoraldrift.

(c)Layout(usability)In the layout of groins, attention shall be paid to the fact that excessive reduction of longshoresedimenttransportbyinstallationofgroinsmayincreasethepossibilityofshorelineretreatonthesurroundingcoast.

References

1) TechnicalCommitteeforCoastalProtectionFacilities:Technicalstandardsandcomment\aryofcoastalprotectionfacilities,JapanPortAssociation,pp.3-77-3-85,2004


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15 ParapetsMinisterial OrdinancePerformance Requirements for Parapets

Article 23 The provisions of Article 16 shall be applied correspondingly to the performance requirements forparapets.

Public NoticePerformance Criteria of Parapets

Article 46 TheprovisionsofArticle39shallbeappliedtotheperformancecriteriaofparapetswithmodificationsasnecessary.

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[Technical Note]

16 Siltation Prevention Facilities16.1 General

(1) Incaseswheresiltationofharborsandwaterwaysisexpected,themodeofsiltationshallbeanalyzedbasedonanadequate investigationof thepotentialcausesofsiltation,andappropriatecountermeasuresshallbe taken,consideringthevarioustypesofeffectscausedbysiltationpreventionworks,safenavigationofshipsandeconomy.

(2)CausesofSiltationCausesofsiltationarelistedbelow.

① Invasionandaccumulationoflittoraldriftmainlycausedbywavesorthatcausedbycurrents

② Settlingandaccumulationofrivererosionsediments

③ Depositionofwindblownsand

④Movementofsedimentswithintheobjectiveareaandchangeinlocationofdeposition

⑤Movementofsedimentsduetodisturbancesintheharbor,collapseofslopesinwaterways,andformationofsandwaves.

16.2 Facilities for Trapping Littoral Drift and River Erosion Sediment

(1)When it is aimed to prevent shoaling due to littoral drift bymeans ofmaintenance dredging, an appropriatefacilitytotrapthesedimentshouldbebuiltataproperlocation,atwhichthefacilitycanpreventsedimentfrominvadingtowaterwaysorbasins.Thefacilityshouldbeabletoreducethewaveactionsarounditandincreasethedredgingefficiency.Thetypeandlayoutofthesesandtrapfacilitiesispreferabletobedeterminedbytakingintoconsiderationtheircapabilitytotrapthesediment,thedredgingconditions,andtheconstructionandoperationalcosts,basedonadequateinvestigationsandresearches.

(2)FacilitiestoTraptheSedimentTransportAs themethod to trap the sediment, provisions to limit sedimentdeposition area are commonly employed invariouscountries,bymeansofbuildingadetachedbreakwaterorpartiallyreducingthecrownheightofupdriftbreakwater.Therearealsosedimenttrapssuchaspocketdredgingexecutedinthewaterwayscrossingalargesandbarintheseafloorofstraits,whichisgraduallyrestoredbynaturalprocessafterdredging.Pocketdredgingisalsodoneontheriverbed,whereshoalingoccursbyriverdischargedsediment.

(3)ProperPositioningofSedimentTrapThesedimenttrapsmaybeinstalledinareaswheredepositionoccurseasilyundernaturalconditions,asshowninFig. 16.2.1(a),(b),and(c),orartificialconditionsmaybecreatedtoencouragesedimentstosettleoutofflowswithahighconcentrationoflittoraldrift,asshowninFig. 16.2.1(d),(e),and(f).Toidentifysuitablelocationsofthistypeandcapturelittoraldriftinthemostefficientmanner,anadequateunderstandingoftheconditionandmechanismofsedimenttransportisindispensable.Furthermore,inselectingthepositionsforsedimenttraps,inadditiontosedimenttrappingefficiency,incaseswherethetrappedsedimentswillbedredged,itispreferableto give adequate consideration to dredging conditions, in otherwords, to easilymaintaining thewater depthnecessaryfornavigationofdredgersandcalmconditionsduringnavigationandwork.


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(a)

Sea bottom shoal Pocket dredging

Pocket dredgingWaterway

(b)

River mouth harborRiver mouth harbor

(c)

(d) (e) (f)

Submergedbreakwater

Breaking wave

Fig. 16.2.1 Positioning of Sediment Traps

16.3 Wind Blown Sand Prevention Work16.3.1 General

Wind-blownsand,i.e.,sandthatismovedbywinds,iscarriedintoharborsorwaterwayswhereitsettlesanddeposits,andcauseshoalingthere.Insomecasesitalsoaccumulatesonroadsurfacesandisdispersedintoresidentialareas,disruptingthedailylivingoftheresident.Inparticular,therearemanyinstancesthatopendiggingofduneorlandreclamationcauseproblemsrelatedtowind-blownsand,andthoroughcountermeasuresmustbepreparedinadvance.

References

1) OZASA,H.:FieldInvestigationofSubmarineSandBanksandLargeSandWaves,Rept.ofPHRIVol.14,No.2,pp.3-46,1975

2) Tanaka,K.,Y.Nakajima,H.EndouandE.Kinnai:Saboatcoast(Coastalerosioncontrol),SaboScience,CompendiumofSaboSeries,III-9,JapanSocietyofErosionControlEngineers,Ishibashi-shotenPublishing,1985

3) JSCE,CivilEngineeringHandbook,Vol.II,pp.2135-2136,1989

Documents

PART III FACILITIES, CHAPTER 4 PROTECTIVE FACILITIES FOR ...ocdi.or.jp/tec_st/tec_pdf/tec_dw/tech_635_675.pdf · (4) The curtain wall breakwaters can be broadly divided into the single-curtain-walled