PART II ACTIONS AND MATERIAL STRENGTH REQUIREMENTS, CHAPTER 5 EARTH PRESSURE AND WATER PRESSURE – 271 – Chapter 5 Earth Pressure and Water Pressure Public Notice Earth Pressure and Water Pressure Article 14 1 Earth pressure shall be set appropriately based on the ground conditions in consideration of the structure of the facilities concerned, imposed loads, the action of earthquake ground motions, and others. 2 Residual water pressure shall be set appropriately in consideration of the structure of the facilities concerned, the surrounding ground conditions, tide levels, and others. 3 Dynamic water pressure shall be set appropriately in consideration of the structure of the facilities concerned, the action of earthquake ground motions, and others. [Technical Note] 1 Earth Pressure 1.1 General The behavior of soil varies with physical conditions such as grain size, void ratio and water content, and with stress history and boundary conditions, which also affect earth pressure. The earth pressure discussed in this chapter is the pressure by ordinary soil. The earth pressure generated by improved soil and reinforced soil will require separate consideration. The earth pressure during an earthquake for design mentioned herein, is based on the concept of the seismic coefficient method and is different from the actual earth pressure generated during an earthquake caused by dynamic interaction between structures, soil and water. However, this earth pressure can generally be used in performance verifications as revealed by analyses of past damage due to earth pressures during earthquakes. The hydrostatic pressure and dynamic water pressure acting on a structure should be calculated separately. (1) Earth Pressure (Relating to Item 1 of the Public Notice Above) In setting earth pressure, appropriate consideration should be given to the earth pressure state, namely whether it is an active or a passive earth as a result of structure behavior etc., and the design situation, in accordance with the type of soil quality such as sandy or cohesive soil and the structural characteristics of the subject facility. (2) Residual Water Pressure (Relating to Item 2 of the Public Notice Above) Residual water pressure mentioned herein refers to the water pressure arising from the difference in water levels on the front side and rear side of the facility. This difference must be given due consideration in setting residual water pressure. (3) Dynamic Water Pressure (Relating to Item 3 of the Public Notice Above) In verifying the performance of facilities subject to the technical standard, proper consideration should be given, as required, to the effect of dynamic water pressure. (4) Other In verifying the performance of facilities subject to the technical standard, buoyancy should be considered, as required, in addition to these settings. 1.2 Earth Pressure at Permanent Situation 1.2.1 Earth Pressure of Sandy Soil (1) The earth pressure of sandy soil acting on the backface wall of structure and the angle of sliding surface shall be calculated by the following equations: ① Active earth pressure and the angle of failure surface (1.2.1) (1.2.2)
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Chapter 5 Earth Pressure and Water PressurePART II ACTIONS AND MATERIAL STRENGTH REQUIREMENTS, CHAPTER 5 EARTH PRESSURE AND WATER PRESSURE – 275 – (3) Apparent seismic coefficient
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PART II ACTIONS AND MATERIAL STRENGTH REQUIREMENTS, CHAPTER 5 EARTH PRESSURE AND WATER PRESSURE
2Residual water pressure shall be set appropriately in consideration of the structure of the facilitiesconcerned,thesurroundinggroundconditions,tidelevels,andothers.
3Dynamic water pressure shall be set appropriately in consideration of the structure of the facilitiesconcerned,theactionofearthquakegroundmotions,andothers.
[Technical Note]
1 Earth Pressure1.1 GeneralThebehaviorofsoilvarieswithphysicalconditionssuchasgrainsize,voidratioandwatercontent,andwithstresshistoryandboundaryconditions,whichalsoaffectearthpressure.Theearthpressurediscussedinthischapteristhepressurebyordinarysoil.Theearthpressuregeneratedbyimprovedsoilandreinforcedsoilwillrequireseparateconsideration.Theearthpressureduringanearthquakefordesignmentionedherein,isbasedontheconceptoftheseismiccoefficientmethodand isdifferent from theactualearthpressuregeneratedduringanearthquakecausedbydynamicinteractionbetweenstructures,soilandwater. However, thisearthpressurecangenerallybeusedinperformanceverificationsasrevealedbyanalysesofpastdamageduetoearthpressuresduringearthquakes. Thehydrostaticpressureanddynamicwaterpressureactingonastructureshouldbecalculatedseparately.
TECHNICAL STANDARDS AND COMMENTARIES FOR PORT AND HARBOUR FACILITIES IN JAPAN
where
② Passiveearthpressureandtheangleoffailuresurface.
(1.2.3)
(1.2.4)
where
with pai,ppi :active andpassive earth pressures, respectively, acting on the backface of thewall at the bottomlevelofthei-thsoillayer(kN/m2) φi :angleofinternalfrictionofthei-thsoillayer(°) γ i :unitweightofthei-thsoillayer(kN/m3) hi : thicknessofthei-thsoillayer(m) Kai,Kpi :coefficientsofactiveandpassiveearthpressures,respectively,inthei-thsoillayer ψ :angleofbatterofbackfacewallfromverticalline(°) β :angleofbackfillgroundsurfacefromhorizontalline(°) δ :angleoffrictionbetweenbackfillingmaterialandbackfacewall(°) ζ i :angleoffailuresurfaceofthei-thsoillayer(°) ω :uniformlydistributedsurchargeonthegroundsurface(kN/m2)
(7)CalculationFormulaforResultantForceofEarthPressureThe resultant forceofearthpressure iscalculatedat each layer. Theobjective force for the i-th layercanbecalculatedusingequation(1.2.6).
Fig. 1.2.1 Schematic Diagram of Earth Pressure Acting on Retaining Wall
1.2.2 Earth Pressure of Cohesive Soil
(1)The earth pressure of cohesive soil acting on the backfacewall of structure shall generally be calculated byfollowingequations:
① ActiveEarthPressure
(1.2.9)
② PassiveEarthPressure
(1.2.10)
where pa :activeearthpressureactingonthebottomlevelofthei-thsoillayer(kN/m2) pp :passiveearthpressureactsonthebottomlevelofthei-thsoillayer(kN/m2) γ i :unitweightofthei-thsoillayer(kN/m3) hi :thicknessofthei-thsoillayer(m) ω :uniformlydistributedsurchargeonthegroundsurface(kN/m2) c :cohesionofsoil(kN/m2)
(3)Active earth pressure can be calculated using equation (1.2.9). If a negative earth pressure is obtained bycalculation,thepressureshouldbeassumedtobezerodowntothedepthwherepositiveearthpressureexerts.
The notations pai,ppi,Kai,Kpi,ζ i,ω,γi,hi,ψ,β,δ and φi, are the same as those defined in 1.2 Earth Pressure at Permanent Situation, equation (1.2.1) to(1.2.4).Also,θisdefinedasfollows.
where pa :characteristicvalueoftheactiveearthpressure(kN/m2) γ i :unitweightofthesoil(kN/m3) hi :thicknessofthesoillayer(m) ω :surchargeloadperhorizontalsurfacearea(kN/m2) c :cohesionofthesoil(kN/m2) θ :expressedascompositeseismicangle 1tan kθ −= (°)or 1tan kθ − ′= (°). k :seismiccoefficient k' :apparentseismiccoefficient ζ a :angleofthefailuresurface(°)
(2)PassiveEarthPressurePassive earth pressure shall be calculated using an appropriate earth pressure formula so that the structuralstabilitywillbesecuredduringanearthquake. Therearemanyunknownfactorsconcerningthemethodfordeterminingthepassiveearthpressureofcohesivesoilduringanearthquake.Conventionally,however,equation (1.2.10)in1.2.2 Earth Pressure of Cohesive Soilforobtaining theearthpressureofcohesivesoil isused in linewithmethodsforearthpressurecalculationatPermanentsituation.Atpresent,equation (1.2.10)canbeusedasanexpedientmethod.
(1)Theearthpressureactingonthesoilbelowthewaterlevelduringanearthquakecanbecalculatedaccordingtotheproceduresoutlinedin1.3.1 Earth Pressure of Sandy Soil and1.3.2 Earth Pressure of Cohesive Soil, byusingtheapparentseismiccoefficientwhichisgenerallydeterminedbythefollowingequation:
(1.3.7)
where k' :apparentseismiccoefficient γ t :unitweightofsoillayerabovetheresidualwaterlevel(kN/m3) hi :thicknessofthei-thsoillayerabovetheresidualwaterlevel(m) γ :unitweightintheairofsaturatedsoillayer(kN/m3) hj :thicknessofthej-thsoillayerabovethelayerforwhichearthpressureisbeingcalculatedbelow
theresidualwaterlevel(m) ω :surchargeloadperunitareaofthegroundsurface(kN/m2) h :thicknessofsoillayerforwhichearthpressureisbeingcalculatedbelowtheresidualwaterlevel(m) k :seismiccoefficient
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TECHNICAL STANDARDS AND COMMENTARIES FOR PORT AND HARBOUR FACILITIES IN JAPAN
PART II ACTIONS AND MATERIAL STRENGTH REQUIREMENTS, CHAPTER 5 EARTH PRESSURE AND WATER PRESSURE
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2 Water Pressure2.1 Residual Water Pressure
(1)When mooring facilities etc. have watertight structures or when backfilling material and backfilling soil(hereinafterreferredtointhisparagraphas"backfilling")havelowpermeability,thereisatimedelayinthewaterlevelchangesinthebackfillingasopposedtothewaterlevelatthefrontandthedifferenceofwaterlevelappears.Whencarryingoutperformanceverificationsonmooringfacilitiesetc.,whatneedstobecheckedistheconditionsthatdevelopwhenthewaterlevelinthebackfillingishigherthanthatatthefrontandwhenthatdifferenceisatitsgreatest.Residualwaterpressurereferstothewaterpressureactingonthemooringfacilitiesetc.underthiscondition. Themagnitudeoftheresidualwater-leveldifferencevariesdependingonthepermeabilityofthewallsandsurroundingmaterialsmakingup themooring facility etc. aswell as the tidal range. Thegeneralvalues forresidualwater-leveldifferencebystructuraltypeareshowninsectionsrelatingtoperformanceverificationoftherespectivefacilities.Valuesotherthanthesegeneralvaluesmaybeusedwhendeterminingresidualwater-leveldifferencefromsurveysconductedonsimilarstructuresnearbyorfrompermeabilitycheckscarriedoutonthewallsandsurroundingground.
where pw :residualwaterpressure(kN/m2) ρwg :unitweightofseawater(kN/m3) y :depthofsoillayerfromtheresidualwaterlevel(m) hw :waterleveldifferencebetweenthewaterlevelinfrontandbehindthefacility(m)
Residual Water Level R.W.L
Resid
ual W
ater
Pre
ss
y
ghw wρ
wh
Fig. 2.1.1 Schematic Diagram of the Residual Water Pressure
(4)Afterafacilityiscompleted,thepermeabilityofitswallsandsurroundingmaterialsmaydiminishwithtime.Therefore,when the anterior tidal range is sizeable, itwould be preferable to take that into consideration indeterminingresidualwater-leveldifference.
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TECHNICAL STANDARDS AND COMMENTARIES FOR PORT AND HARBOUR FACILITIES IN JAPAN
2.2 Dynamic Water Pressure
(1) Items(2)through(8)belowshouldbefollowedwhenusingperformanceverificationequationsthatmakeuseofcharacteristicvaluesofdynamicwaterpressurewhereasitem(9)shouldbefollowedinperformingverificationsthat use techniques such as the finite elementmethod for taking the effects of dynamicwater pressure intoconsideration.
(2)Normally,methods based on the dynamicwater pressure on steady oscillation 1) are used for calculating thecharacteristicvaluesofthedynamicwaterpressure.However,inviewofthephaserelationshipofotheractions,whenaparticularneedarises,thedynamicwaterpressureonirregularoscillationshouldbecalculated. Also, ifa liquidoccupiesspaces inside thefacility, thedynamicpressureof the liquidmustbe takenintoconsideration.Ifdynamicwaterpressureisactingonbothsidesofthefacility,thesumoftheresultantforceofthedynamicwaterpressurebecomestwo-fold.Dynamicwaterpressureneedsnotbeconsideredinthefollowingcases:
①When performance verifications can be performed without taking dynamic water pressure directly intoconsiderationduetostructuralcharacteristics;
where pdw :dynamicwaterpressure(kN/m2) kh :seismiccoefficient γw :unitweightofwater(kN/m3) H :heightofstructurebelowthestillwaterlevel(m) y :depthofthedynamicwaterpressurecalculationlevelfromthestillwaterlevel(m)
The resultant forceofdynamicwaterpressureand itsactingheightcanbecalculatedby the followingequation:
(1)EffectsofLiquefactionintheCaseofLevel1EarthquakeGroundMotionsAs for theconsiderationof liquefaction in thecaseof level2 earthquakegroundmotions,measuresagainstliquefactionaretakentoprotectthegroundconcernedwhenliquefactionispredictedandjudgedtooccur,takingaccountoftheeffectsofliquefactiononstructuresandthesurroundingsituationsofthefacilitiesconcerned.
As for theconsiderationof liquefaction in thecaseofLevel2earthquakegroundmotions, themethodsof takingmeasures against ground liquefaction and the necessity of their implementation shall be determined based on acomprehensiveevaluationofthesituationsofthefacilitiesconcerned.RefertoChapter 4 EarthquakesofthisPartIIandthedescriptionontheperformanceverificationoffacilitiesinPart3fortheevaluation.
① JudgmentbasedongrainsizeThesubsoilsshouldbeclassifiedaccordingtograinsize,byreferringtoFig.2.1,towhichapplicationdependsonthevalueoftheuniformitycoefficient.Thethresholdvalueoftheuniformitycoefficient(Uc=D60/D10)is3.5,whereUc istheuniformitycoefficient,andD60andD10denotethegrainsizescorrespondingto60%and10%passing,respectively.Soilisjudgednottoliquefywhenthegrainsizedistributioncurveisnotincludedintherange“possibilityofliquefaction”inFig. 2.1.
PART II ACTIONS AND MATERIAL STRENGTH REQUIREMENTS, CHAPTER 6 GROUND LIQUEFACTION
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Clay Silt Sand GravelGrain size (mm)
For soil with large uniformity coefficient (Uc 3.5)
Perc
enta
ge p
assi
ng b
y m
ass (
%)
00.01 0.1 1.0 10
25
50
75
100
0.005 0.075 2.0
Very large possibilityof liquefaction
Possibility of liquefaction
Fig. 2.1(a) Range of Possible Liquefaction (Uc ≧ 3.5)
Perc
enta
ge p
assi
ng b
y m
ass (
%)
Clay Silt
Grain size (mm)
Sand Gravel
Very large possibilityof liquefaction
Possibility of liquefaction
For soil with small uniformity coefficient (Uc 3.5)
00.01 0.1 1.0 10
25
50
75
100
0.005 0.075 2.0
Fig. 2.1(b) Range of Possible Liquefaction (Uc < 3.5)
Whenthegrainsizedistributioncurvespansthe“possibilityofliquefaction”range,asuitableapproachisrequiredtoexaminethepossibilityofliquefaction.Forsoilwithalargeportionoffinegrainsizedistribution,acyclictriaxialtestshouldbecarriedout.Forsoilwithalargegravelportion,thesoilisdeterminednottoliquefywhenthecoefficientofpermeabilityis3cm/sorgreater.Whentherearesubsoilswithpoorpermeabilitysuchasclayorsiltontopofthetargetsubsoilinthiscase,however,itshouldbetreatedassoilthatfallswithintherangeof“possibilityofliquefaction”. Apermeabilitytestforthesoilwiththepermeabilityoflargerthan3cm/sshallbeaspecialmethod.3) Amethod of indirect estimation of permeability is availablewhen the permeabilitymeasurement is difficult.However,careaboutthesoilcharacteristics,suchascontentoffineparticlesshallbepaidtoapplytheindirectestimationmethod.
② PredictionandjudgmentofliquefactionusingequivalentN-valuesandequivalentaccelerationForthesubsoilwithagrainsizethatfallswithintherange“possibilityofliquefaction”showninFig. 2.1,furtherinvestigationsshouldbecarriedbythedescriptionsbelow.
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TECHNICAL STANDARDS AND COMMENTARIES FOR PORT AND HARBOUR FACILITIES IN JAPAN
Fig. 2.2 Calculation Chart for Equivalent N-value, the Straight Lines show the Relationship between N-values and Effective Overburden Pressures when Relative Densities are Constant
PART II ACTIONS AND MATERIAL STRENGTH REQUIREMENTS, CHAPTER 6 GROUND LIQUEFACTION
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Equivalent acceleration (Gal)
Equi
vale
nt N
-val
ue
ⅠⅡ
Ⅲ
Ⅳ
0 100 200 300 400 500 6000
5
10
20
25
30
15
(333,25)
(300,16)(300,16)(450,16)(450,16)
(150,7)(150,7)
(100,7)(100,7)(66,7)
Fig. 2.3 Classification of Soil Layer with Equivalent N-Value and Equivalent Acceleration
③ Prediction,judgmentandcorrectionofN-valueswhenthefractionoffinescontentisrelativelylarge.
(a)When the fines content, grain size of 75 μm or less, is 5% or greater, the equivalentN-value should becorrectedbeforeapplyingFig. 2.3,thenthesubjectsoilshouldbeevaluatedtowhichrangeofItoIVinFig. 2.3itfalls.CorrectionsoftheequivalentN-valuearedividedintothefollowingthreecases.
② Theproperconsiderationofthestressstateinthegroundandtheirregularityoftheactionscausedbygroundmotionsisimportantfortheresultsoftheseismicresponseanalysesofthegroundandthoseofcyclictriaxialteststoshowactualphenomenaintheground.
(5)JudgmentofOverallLiquefactionIn the judgmentofoverall subsoil liquefaction for a siteconsistingof soil layers, thecomprehensivedecisionshouldbemadebasedonajudgmentforeachlayerofsubsoil.
1) CoastalDevelopmentInstituteofTechnology(CDIT):Handbookofliquefactionofreclaimedland(RevisedEdition),19972) Yamazaki,H.,K.Zen andF.KoikeStudy of theLiquefactionPredictionBased on theGrainDistribution and theSPT
TECHNICAL STANDARDS AND COMMENTARIES FOR PORT AND HARBOUR FACILITIES IN JAPAN
Chapter 7 Ground Subsidence
Public NoticeGround Subsidence
Article 15Influenceofgroundsubsidenceshallbeassessedwithappropriatedmethodsbasedonthegroundconditionsin consideration of the structures of the facilities, imposed load, and the surrounding situations of thefacilitiesconcerned.
[Technical Note]
1.1.1 Ground Subsidence
Ground subsidence includes immediate settlement, consolidation settlement, uneven settlement, lateraldisplacementetc.Theeffectsofgroundsubsidenceshallbeevaluatedbasedongroundconditionsusingpropermethodsandproperlytakingaccountofthestructuresofthefacilitiesconcerned,surcharges,andthe actions caused by groundmotions. The evaluation of ground subsidence may refer toChapter 3 Geotechnical ConditionsofPart IIand2.5 Settlement of Foundation in Chapter 2 of Part III.
PART II ACTIONS AND MATERIAL STRENGTH REQUIREMENTS, CHAPTER 8 SHIPS
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Chapter 8 Ships
Public NoticeDimensions of Design Ships and Related Matters
Article 181Thedimensionsofdesignships(hereinafterreferstotheshipsusedastheinputdataintheperformanceverification of the facilities subject to theTechnical Standards) shall be set according to themethodsprovidedinthesubsequentitems:(1)Inthecasewheredesignshipsareidentifiable,theirdimensionsshallbeused.(2)Inthecasewheredesignshipsareunidentifiable, thedimensionsshallbeproperlysetbasedonthe
(2)The actions from shipmovements shall be setwith appropriatemethods by taking account of thedimensionsofdesignships,thestructuresofthefacilitiesconcerned,mooringmethods,characteristicsofmooringsystem,andthewinds,waves,watercurrents,and/orothersactingondesignships.
TECHNICAL STANDARDS AND COMMENTARIES FOR PORT AND HARBOUR FACILITIES IN JAPAN
(2)In the case where design ships are unidentifiable in advance such case as the public port facilities, thestandardizedvaluesof tonnages, lengthsoverall, lengthsbetweenperpendiculars,moldedbreadths,andfullloaddraftsbyshiptypeshowninTable 1.1maybeusedforthedesigns.ThestandardvaluesinTable 1.1arepreparedbasedonthestatisticalanalysisofthedimensionsoftheexistingshipswithacoverageratioof75%foreachtonnagecategory.Thedataonthedimensionsofsmallcargovesselsusedforthestandardvaluesvarywidely,hencethedimensionsofsmallcargovesselsshouldbesetusingthevaluesinTable 1.2asreferencesandtakingintoconsiderationthetrendsofshipsinports.Thegrosstonnage,GT,giveninTable 1.1basicallymeans international gross tonnage, but in somecases it refers todomesticgross tonnagedependingon thecharacteristicsofthedatausedforsettingthestandardvalues.Suchcases,wherethegrosstonnage,meansthedomesticgrosstonnage,areclearlyindicatedinTable 1.1.Thetableusesthecommonlyusedtonnage,grosstonnageordeadweighttonnage,ofeachshiptypeastherepresentativeindex. Fig. 1.1showstheprincipaldimensionsusedinthetables.
Length overall (Loa)
Length between perpendiculars (Lpp)Full load water line
After perpendicularMolded breadth (B)
Forward perpendicular
W.L
W..L
Full
load
dra
ft ( d
)
Mol
ded
dept
h
Fig. 1.1 Principal Dimensions of Ships
Table 1.1 Standard Values of the Principal Dimensions of Design Ships
(7)The container ships of under-panamax, panamax, and over-panamax types have characteristic dimensionspeculiartoeachtype,andhencethesettingoftheirdimensionsmayrefertoTables 1.5to1.9.ThesettingofthedimensionsofverylargecrudeoilcarriermayrefertoTable 1.10.
* This table is prepared based on “LMIUShippingData (2006.8).”As ofAugust 2006, 100 container ships have atonnageofover100,000DWT. In this table,eachDWTcategoryrepresentsacasewhere thereare threeormoreshipswiththesameDWTcategory,andshowstheprincipaldimensionsoftheshipwiththelargestcontainercarryingcapacityamongthemexceptoneshipof156,907DWT.
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TECHNICAL STANDARDS AND COMMENTARIES FOR PORT AND HARBOUR FACILITIES IN JAPAN
Table 1.9 Principal Dimensions of the Container Ships with a Container Carrying Capacity of Over 8,000 TEU
PART II ACTIONS AND MATERIAL STRENGTH REQUIREMENTS, CHAPTER 8 SHIPS
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2 Actions Caused by Ships2.1 General2.1.1 Ship Berthing
(1)Theactionscausedbyberthingshipstomooringfacilitiesshallbedeterminedusingappropriatemethods,takingaccount of the dimensions of design ships, berthingmethods, berthing velocities, the structures of mooringfacilities,etc.
(4)Thenormalperformanceverificationoffendersystemsshalltakeaccountofnotonlydominatingberthingforcesof ships but also the impact forces caused by themotions ofmoored ships. In the performance verificationofmooringposts, the tractive forcesdue to themotionsofmoored ships causedby thewindpressure forcesareimportant.Theimpactforcescausedbythemotionsofmooredshipsarestronglyaffectedbythetypesofdesign ships,wavecharacteristics, thedisplacement-restoring forcecharacteristicsof fender systemsetc., andwindpressureforcesarestronglyaffectedbythetypesofdesignships,henceitispreferablefortheperformanceverificationtothoroughlystudytheconditionsofdesignships,wavecharacteristics,thestructuresofquaywalls,thecharacteristicsofmooringequipmentetc.
2.2 Actions Caused by Ship Berthing
(1)BerthingEnergyofShip
① Theactionscausedbyshipberthingaregenerallycalculatedfromtheberthingenergyofships.Theberthingenergyofashipcanbecalculatedfromthefollowingequationbyusingthemassoftheship,theberthingvelocityof theship, theeccentricity factor, thevirtualmass factor, theflexibilityfactor,and theberthconfigurationfactor.Thesubscriptk intheequationreferstothecharacteristicsvalue.
(2.2.1)
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TECHNICAL STANDARDS AND COMMENTARIES FOR PORT AND HARBOUR FACILITIES IN JAPAN
where Ef :berthingenergyofship(kNm) Ms :massofship(t) Vb :berthingvelocityofship(m/s) Cm :virtualmassfactor Ce :eccentricityfactor Cs :flexibilityfactor Cc :berthconfigurationfactor
② There are methods of estimating the berthing energy of ships such as statistical methods, methods usinghydraulicmodel tests,andmethodsusingfluiddynamicsmodels inaddition tokineticenergyofmethod.1)However, regarding these alternativemethods, thedatanecessary fordesignare insufficient and thevaluesofthevariousfactorsusedinthecalculationsmaynotappropriatelyproperlygiven.Thus,thekineticenergymethodisgenerallyused.
③ If it is assumed that a berthing shipmoves only in the abeamdirection, then the kinetic energyEs (kNm)becomesequalto 2 2s bM V . However,whenashipisberthingatadolphin,aquaywalloraberthingbeamequippedwithfendersystems,theenergyabsorbedbythefendersystems,i.e.,theberthingenergyEf oftheship,willbecomeEsfconsideringthevariousrelevantfactors,wheref= Cm Ce Cs Cc
(2)MassofShipThemassofshipinthecalculationequationoftheberthingenergyofshipsmeansthefullloaddisplacementoftheship.Equation (2.2.2)mayalsobeusedtoshowtherelationsbetweenthecharacteristicvaluesofthefullloaddisplacements(DT)anddeadweighttonnages(DWT)orgrosstonnages(GT)ofships.Theywerecalculatedastheregressionequationscovering75%ofthetotalstatisticaldataoffullloaddisplacements(DT)withrespecttodeadweighttonnages(DWT)orgrosstonnages(GT),usingtheregressionequationsandstandarddeviationsshowninTable 1.4 Regression Equations for Dead Weight Tonnages (DWT) or Gross Tonnages (GT) and Displacement Tonnages (DSP) in 1. Principal Dimensions of Design Ships. These relationsareapplicablewithintherangeoftonnageshowninTable 1.1.Thesubscriptkintheequationsreferstothecharacteristicvalues.
① It is preferable to determine the characteristic values of the berthing velocities of ships based on actualmeasurementsorreferencesonthepreviousmeasurementsofberthingvelocities,takingaccountofthetypesofdesignships,loadedconditions,thelocationsandstructuresofmooringfacilities,meteorologicalphenomenaandoceanographicphenomena,theusageoftugboatassistanceandtheirsizesetc.
③ Specialshipssuchasferriesandroll-onroll-offshipsandsmallcargoshipsoftenuseberthingmethodsdifferentfromlargeships,assuchthattheyberthbythemselveswithoutusingtugboatsortheyshiftparalleltothefacelinesofquaywallsiftheyareequippedwithboworsternlamps.Theberthingvelocitieshenceshallbecarefullydeterminedbasedonactualmeasurementstakingaccountoftheirberthingmethods.
PART II ACTIONS AND MATERIAL STRENGTH REQUIREMENTS, CHAPTER 8 SHIPS
Fig. 2.2.1 Relationship between Ship Maneuvering Conditions and Berthing Velocity by Ship Size 2)
⑤ According to the study reports 3), 4) onberthingvelocity, theberthingvelocity is usually less than10 cm/sforgeneralcargoships,butonlyinafewcasesareover10cm/s(seeFig. 2.2.2).Theberthingvelocityonlyoccasionallyexceeds10cm/sfor largeoil tankersthatuseoffshoreberths(seeFig. 2.2.3). Evenforferrieswhichberthundertheirownpower,theberthingvelocityinmanycasesislessthan10cm/s.Nevertheless,sincethereareafewcasesinwhichtheberthingvelocityisover15cm/s,duecaremustbetakenwhenverifyingtheperformanceofferryquays(seeFig. 2.2.4).Basedontheabove-mentionedstudyreports,thecargoloadingconditionhasaconsiderableinfluenceontheberthingvelocity.Inotherwords,whenashipisfullyloaded,whichresultsinsmallunder-keelclearance,theberthingvelocitytendstobelower,whereaswhenitislightlyloaded,whichresultsinalargeunder-keelclearance,theberthingvelocitytendstobehigher.
PART II ACTIONS AND MATERIAL STRENGTH REQUIREMENTS, CHAPTER 8 SHIPS
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15
20
10
5
00 10,000 20,000 30,000 40,000 50,000
General cargo shipsContainer shipsPure car carriers
V (c
m/s
)
Dead Weight Tonnage (DWT )
R=-0.38A=-0.0009B= 66.1Y=AX+B
Fig. 2.2.5 Relationship between Dead Weight Tonnage and Berthing Velocity 5)
⑥ Fig. 2.2.6 shows a berthing velocity frequency distribution obtained from actual measurement records ofberthingvelocitiesatoffshoreberthsusedbylargeoiltankersofaround200,000DWT.Itshowsthatthehighestmeasuredberthingvelocitywas13cm/s. If thedataareassumedtofollowaWeibulldistribution, then thenon-exceedenceprobabilityoftheberthingvelocitybelowthevalueof13cm/swouldbe99.6%.Themeanμ is4.4cm/sandthestandarddeviationσis2.08cm/s.ApplicationoftheWeibulldistributionyieldstheprobabilitydensityfunctionf(Vb)asexpressedinequation (2.2.3):
Poisson distribution m = 3Poisson distribution m = 4Weibull distributionNormal distribution
μ=4.41σ=2.08
N=738
V (cm/s)
Fig. 2.2.6 Frequency Distribution of Berthing Velocity 6)
⑦ Small general cargo ships approach to berths by controlling their positions under their ownpowerwithoutassistanceoftugboats.Consequently,theberthingvelocityisgenerallyhigherthanthatoflargerships,andinsomecasesitmayevenexceed30cm/s.Hence,itisnecessarytopayattentiontothis.Forsmallshipsinparticular,itisnecessarytocarefullydeterminetheberthingvelocitybasedonactuallymeasureddata.
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TECHNICAL STANDARDS AND COMMENTARIES FOR PORT AND HARBOUR FACILITIES IN JAPAN
① Virtualmassfactorscanbecalculatedfromthefollowingequations:
(2.2.4)
(2.2.5)
where Cb :blockcoefficient :displacementvolumeofship(m3) Lpp :lengthbetweenperpendiculars(m) B :moldedbreadth(m) d :fullloaddraft(m)
ThecalculationrequirestheuseofthelengthsbetweenperpendicularsLpp,moldedbreadthsB,andfullloaddraftsdofdesignships.ThecaseswheredesignshipsareofastandardshiptypemayusethevaluesshowninTable 1.1 Standard Values of the Principal Dimensions of Design ShipsincludedinCommentary.
① Eccentricityfactorscanbecalculatedfromthefollowingequation:
(2.2.7)
where l :distancefromtheship’scontactpointtothecenterofgravityoftheshipmeasuredparallelto
thefacelineofthemooringfacility(m) r :radiusofrotationaroundtheverticalaxispassingthroughthecenterofgravityoftheship(m)
② Duringtheberthingprocess,ashipisnotalignedperfectlyalongthefacelineoftheberth.Thismeansthatwhentheshipcomesintocontactwiththefendersystems,itstartsyawingandrolling.Thisresultsinthelossofapartoftheship’skineticenergy.Theamountofenergylossbyrollingisnegligiblysmallcomparedwiththatbyyawing.Equation (2.2.7)thusonlyconsiderstheamountofenergylossbyyawing.
③ r/Lpp isafunctionoftheblockcoefficientCb oftheshipandcanbeobtainedfromFig. 2.2.7.10)Alternatively,onemayusethelinearapproximationshowninequation(2.2.8).
(2.2.8)
PART II ACTIONS AND MATERIAL STRENGTH REQUIREMENTS, CHAPTER 8 SHIPS
–303–
where r :radiusof rotation (radiusofgyration); this is related to themomentof inertia Iz around the
ThecalculationrequirestheuseofthelengthsbetweenperpendicularsLppofdesignships.Thecaseswheredesign ships areof a standard ship typemayuse thevalues shown inTable 1.1 Standard Values of the Principal Dimensions of Design ShipsincludedinCommentary.
0.30
0.28
0.26
0.24
0.22
0.200.5 0.6 0.7 0.8 0.9 1.0R
adiu
s of g
yrat
ion
in th
e lo
ngitu
dina
l dire
ctio
n ( r
)
Leng
th b
etw
een
perp
endi
cula
rs (L
pp)
Block coefficient Cb
Fig. 2.2.7 Relationship between the Radius of Gyration around the Vertical Axis and the Block Coefficient 9)
(7)BerthConfigurationFactorThewatermass compressed between berthing ship andmooring facility behave like a cushion and decreasetheenergytobeabsorbedbyfendersystems.TheberthconfigurationfactorCcneedstobedeterminedtakingaccountofthiseffect.Thisphenomenonisconsideredtorelatetoberthingangles,theshapesofshiphull,under-keelclearances,andberthingvelocities,butonlylimitedquantitativestudiesonthephenomenonhavebeenmade. ThecharacteristicvalueofberthconfigurationfactorCckmaynormallybesetasCck=1.0.
2.3 Actions Caused by Ship Motions
(1)MotionsofMooredShips
① Actionscausedbythemotionsofmooredshipsaregenerallycalculatedbymotioncalculation,byappropriatelysettingwaveforces,windpressureforces,andwatercurrentpressureforces.
② Theshipsmooredtothemooringfacilitiesconstructedintheopenseaorclosetoportentrancesorinportswherelongperiodwavesinvadeandthosemooredinroughweatherarepossibletomovebytheactionsofwaves,winds,andwatercurrents.Thekineticenergygeneratedbythemotionsofmooredshipssometimesexceedstheberthingenergy.Insuchcases,itispreferablefortheperformanceverificationofmooringpostsandfendersystemstotakeaccountofthetractiveforcesandimpactforcesgeneratedbythemotionsofmooredships.12)Intheportsfacingtheopenseainparticular,ithasbeenfrequentlyreportedthatthelongperiodoscillationsofmooredshipscausedbythelongperiodwavesresultedinadifficultywithsmoothcargohandling.13),14)Careshouldbetakeninsuchports.
③ As a general rule, the oscillations of a moored ship should be analyzed through numerical simulation inconsiderationoftherandomvariationsoftheactionsandthenonlinearityofthedisplacement-restoringforcecharacteristics of themooring system. However,when such a numerical simulation of shipmotions is notpossible,orwhentheshipismooredatasystemthatisconsideredtobemore-or-lesssymmetrical,onemayobtainthedisplacementofandloadsonthemooringsystemeitherbyusingfrequencyresponseanalysisforregularwavesorbyreferringtotheresultsofmotioncalculationonafloatingbodymooredatasystemthathasdisplacement-restoringforcecharacteristicsofbilinearnature.15)
④ Thewaveforceactingonashipconsistsofthewave-excitingforceduetoincidentwavesandthewave-makingresistanceforceaccompaniedbythemotionsoftheship.16)Thewave-excitingforceduetoincidentwavesisthewaveforcecalculatedforthecasethatthemotionsoftheshiparerestrained.Thewave-makingresistanceforceisthewaveforceexertedontheshipwhentheshipundergoesamotionofunitamplitudeforeachmodeofmotions.Thewave-makingresistanceforcecanbeexpressedasthesummationoftwofactors,oneisproportionaltotheaccelerationoftheshipandtheotherisproportionaltothevelocity.Theformercanbeexpressedasanaddedmasswhenitisdividedbytheacceleration,whilethelattercanbeexpressedasadampingcoefficientwhenitisdividedbythevelocity.17)Inaddition,thenonlinearfluiddynamicforcethatisproportionaltothesquareofthewaveheightactsontheship,see4.9 Actions on Floating Body and its Motions in Chapter 2.
① Thewaveforceactingonamooredshipshallbecalculatedusinganappropriatemethod,consideringthetypeofshipandthewaveparameters.
PART II ACTIONS AND MATERIAL STRENGTH REQUIREMENTS, CHAPTER 8 SHIPS
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② Thewave force actingon amoored ship is calculatedusing appropriate analysismethods such as the stripmethod,thesourcedistributionmethod,theboundaryelementmethod,orthefiniteelementmethod;themostcommonmethodusedforshipsisthestripmethod.
① Thewindloadactingonamooredshipshallbedeterminedusinganappropriatecalculationformula.
② Itispreferabletodeterminethewindloadactingonamooredshipinconsiderationofthetimefluctuationofthewindvelocityandthecharacteristicsofthewinddragcoefficientsinrespectofthecross-sectionalshapeoftheship.
③ Thewindloadsactingonashiparecalculatedfromequations(2.3.1)to(2.3.3)usingwinddragcoefficientsCXandCYintheXandYdirections,respectively,andwindpressuremomentcoefficientCMaroundthemidship.Thesubscriptkintheequationsreferstothecharacteristicvalues.
(2.3.1)
(2.3.2)
(2.3.3)
where CX :winddragcoefficientintheXdirection(bowdirection) CY :winddragcoefficientintheYdirection(sidedirection) CM :windpressuremomentcoefficientaroundmidship RX :X-directioncomponentofwindloadresultantforce(kN) RY :Y-directioncomponentofwindloadresultantforce(kN) RM :momentofwindloadresultantforcearoundmidship(kNm) ρa :airdensity,whichmaybesetasρa=1.23x10-3(t/m3) U :windvelocity(m/s) AT :above-waterbowprojectedarea(m2) AL :above-watersideprojectedarea(m2) Lpp :lengthbetweenperpendiculars(m)
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TECHNICAL STANDARDS AND COMMENTARIES FOR PORT AND HARBOUR FACILITIES IN JAPAN
⑥ Sincethewindvelocityvariesbothintimeandspace,itshouldbetreatedasfluctuatingwindinthemotioncalculationofamooredship. Davenport 23) andHino 24)haveproposed the frequencyspectra for the timefluctuationsofthewindvelocity.ThefrequencyspectraproposedbyDavenportandHinoaregivenbyequations (2.3.4)and(2.3.5),respectively.
(2.3.4)
(2.3.5)
where Su( f ):frequencyspectrumofwindvelocity(m2/s) U10:averagewindvelocityatthestandardheightof10m(m/s) Kr:frictioncoefficientforthesurfacedefinedwiththewindvelocityatthestandardheight;on thesea,itisconsideredthatKr=0.003isappropriate. α:powerexponentwhentheverticaldistributionofthewindvelocityisexpressedbyapower law[U∝(Z/10)α]] z:heightabovethesurfaceofthegroundorthewater(m) m:correctionfactorrelatingtothestabilityoftheatmosphere;m istakentobe2incaseofa storm.
(4)WaterCurrentPressureForcesActingonShip
① Thecurrentpressure forcedue towatercurrentsactingona ship shallbedeterminedusinganappropriatecalculationformula.
② CurrentpressureforcecausedbycurrentsfromthebowThecurrentpressureforcedevelopedbetweenashipandcurrentsfromthebowcanbecalculatedfromequation(2.3.6).Thesubscriptkintheequationreferstothecharacteristicvalue.
(2.3.6)
where Rf :currentpressureforce(kN) S :submergedsurfacearea(m2) V :currentvelocity(m/s)
③ CurrentpressureforcecausedbycurrentsfromthesideThecurrentpressureforcecausedbycurrentsfromthesidecanbecalculatedfromequation (2.3.7).Thesubscriptkintheequationreferstothecharacteristicvalue.
(2.3.7)
PART II ACTIONS AND MATERIAL STRENGTH REQUIREMENTS, CHAPTER 8 SHIPS
–307–
where R :currentpressureforce(kN) ρo :densityofseawater(t/m3) C :currentpressurecoefficient V :currentvelocity(m/s) B :under-watersideprojectedareaofship(m2)
where Rf :currentpressureforce(kN)ρ0g :unitweightofseawater(kN/m3) t :temperature(°C) S :submergedsurfacearea(m2) V :currentvelocity(m/s) λ :coefficient,whichcanbesetasλ=0.14741foralengthoverallof30mandλ=0.13783fora
① For themotioncalculationofamooredship, thedisplacement-restoringforcecharacteristicsof themooringsystemsuchasmooringropesandfendersshallbemodeledappropriately.
② Thedisplacement-restoringforcecharacteristicsofthemooringsystemsuchasmooringropesandfendersisgenerallynonlinear.Moreover,thedisplacement-restoringforcecharacteristicsoffendersmaypossesshysterisisnature.Inthatcase,itispreferabletomodelthesecharacteristicsappropriatelyforthemotioncalculationofamooredship.25)
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TECHNICAL STANDARDS AND COMMENTARIES FOR PORT AND HARBOUR FACILITIES IN JAPAN
PART II ACTIONS AND MATERIAL STRENGTH REQUIREMENTS, CHAPTER 8 SHIPS
–309–
ashipinsuchawaythatalightlyloadedshipshouldbeabletobemooredsafelyevenwhenthewindvelocityis25to30m/s,withtheassumptionthatthemooringpostsareinstalledattheplaceawayfromthefacelineofthequaywallbyaship’swidthandthatthebreastlinesarestretchedinadirectionof45ºtotheship’slongitudinalaxis.26),27)Thetractiveforcesoobtainedcorrespondstothebreakingstrengthofonetotwomooringropes,wherethebreakingstrengthofamooringropeisevaluatedaccordingtothe Steel Ship Regulations by the Nippon Kaiji Kyokai.Forasmallshipofgrosstonnageupto1,000tons,themooringpostscanwithstandthetractiveforceunderthewindvelocityofupto35m/s. Thetractiveforceactingonabollardhasbeendeterminedbasedonthewindpressureforceactingonashipinsuchawaythatevenalightlyloadedshipshouldbeabletobemooredusingonlybollardsunderthewindvelocityofupto15m/s,withtheassumptionthattheropesatthebowandsternarestretchedinadirectionatleast25ºtotheship’saxis.Thetractiveforcesoobtainedcorrespondstothebreakingstrengthsofonemooringropeforashipofgrosstonnageupto5,000tonsandtwomooringropesforashipofgrosstonnageover5,000tons,wherethebreakingstrengthofamooringropeisevaluatedaccordingtothe Steel Ship Regulations by the Nippon Kaiji Kyokai. Thetractiveforceforabollardthatisusedforspringlinesandisinstalledatthemiddleofaberth,forwhichtheberthingshipsaredesignated,correspondstothebreakingstrengthofonemooringrope,wherethebreakingstrengthofamooringropeisevaluatedaccordingtothe Steel Ship Regulations by the Nippon Kaiji Kyokai. Intheabove-mentionedtractiveforcecalculations,inadditiontothewindpressureforce,ithasbeenassumedthattherearewatercurrentsof2ktinthelongitudinaldirectionand0.6ktinthetransversedirection.
ThatlnhibitSuchMotions,ReportofPortandHarbourResearchInstitute,Vol.37No.4,pp.37-78,199814) CoastalDevelopment InstituteofTechnology:Manual for ImpactAssessmentofLongPeriodWaves inaPort,2004 (in
Japanese)15) Ueda, S.:AnalyticalMethod of ShipMotionsMoored toQuayWalls and theApplications,TechnicalNote of Port and
TECHNICAL STANDARDS AND COMMENTARIES FOR PORT AND HARBOUR FACILITIES IN JAPAN
ResearchInstitute,Vol.22No.4,pp.181-218,1983(inJapanese)18) Goda,Y., Takayama, T. and Sasada, T.: Theoretical and Experimental Investigation ofWave Forces on a FixedVessel
PART II ACTIONS AND MATERIAL STRENGTH REQUIREMENTS, CHAPTER 9 ENVIRONMENTAL ACTIONS
–311–
Chapter 9 Environmental Actions
Public NoticeEnvironmental Influences
Article 19Environmental influences shall be assessed with appropriate methods by taking account of the designworkinglifeofthefacilities,materialcharacteristics,environmentalconditions,maintenancemethods,andtheconditionstowhichthefacilitiesconcernedaresubjected.
[Technical Note]
TheevaluationoftheeffectsofenvironmentalactionsmayrefertoPart I, Chapter 2, 3 Maintenance of Facilities Subject to the Technical StandardsandChapter 11, 2.3 Corrosion Protection forsteelandPart III, Chapter 2, 1.1 Generalforconcrete.