Fender Design. Fender Design

Transcription

1 Fender Design Fender Design 1. Design Data Collection 1.1. The following conditions shall be confirmed prior to the selection of fender Effective berthing energy of ship Berthing structure allowable reaction force Hull allowable surface pressure The position and area to be protected by the fender system Natural force (Inc. wind, current and wave etc.) 1.2. Required Information Vessels Types: General Cargo Vessel, Oil Tank, Container Ships, Bulk Cargo Ships, Ferries, Cruise Liners and Project Boat etc Weight: gross tonnage, dead weight tonnage and displacement tonnage etc Length of Ship Breadth of Ship Depth of Ship Ship loaded draft Freeboard height 1.3. Berthing Structures Types: Wharf, Jetty and Pier etc Structure: Pile type or gravity type Elevation Top deck (platform) level High water and low water level For existing quay structure, the following additional information are required: Space for fender installation with its elevations from seawater level Horizontal allowable force acting on the structure Natural Condition Wind: Direction and speed Current: Direction and speed Wave: Height, period and direction Page 155 of 176

2 - Design Flow Chart Fender System Design In most cases, the actual values of the ships is used to calculate the actual berthing energy. Under some cases the actual values are not available, then the attached list "Standard Size of Vessels" shall be referred for calculations. Page 156 of 176

3 Gross Tonnage GT(ton) TERMINOLOGY DEFINATIONS Total volume of vessel and cargo. it is derived by dividing the total interior capacity of a vessel by 100 cubic feet. Net Tonnage NT(ton) Total volume of cargo that can be carried by; the vessel. Displacement Tonnage DPT(ton) Dead Weight Tonnage DWT(ton) Weight of cargo, fuel, passenger, crew and food on the vessel. Light Weight LOW(ton) Weight of ship. Ballast Weight BW(ton) Total weight of the vessel and cargo when the ship is loaded to draft line. Weight of ship and water added to the hold or ballast compartment of a vessel to improve its stability after it has discharged its cargo. Length of ship Loa or Lpp The length from the top of the bow to the end of the stern of a ship. Breadth of Ship B The distance across the parallel section of the sides of a ship. Loaded Draft Light Draft d d Depth of Ship D The actual Depth of ship. The distance from the water surface to the keel of the ship when the ship is loaded to the freeboard mark. The distance from the water surface to the keel of the ship when the ship is at light. Note: Passenger ship, car carrier and LPG & LNG carriers are normally expressed using GT or NT. DPT=DWT+LW 2. Berth Energy calculation The impacting energy calculation is subject to the ships berthing method which can be defined as following: a. Side Berthing & Dolphin Berthing, as shown in the figure 1 & 2 Figure 1 E=1/2gMd. V 2 Cm. Ce. Cc. Cs Figure 2 Then Figure 3 b. Passing Lock Entrance, as shown in the figure 3 E=1/2Md. (V sina) 2 Cm. Cm. Ce. Cc. Cs Figure 4 c. Ship-To-Ship Berthing, as shown in the figure Figure 5 d. End Berthing, as shown in the figure 5 E=0.5MdV 2 Page 157 of 176

4 Where E - Vessel effective berthing energy Md - Displacement Tonnage (ton) V - Berthing Velocity (m/s) Cm - Added Mass Coefficient Ce - Eccentricity Coefficient Cs - Softness Coefficient, normally takes 1 Cc - Berth Configuration Coefficient, normally takes 1. 1) V Berthing Velocity Berthing velocity is an important parameter in fender system design, it depends upon the sizes of vessel, loading condition, port structure and the easy or difficulty of the approach etc. Therefore the berthing velocity is preferred to be obtained from actual measurements or relevant existing statistic information. When the actual measured speed velocity is not available, the BSI and PIANC etc. standard shall be adopted to determine the required velocity value from the following chart. a. Easy berthing and sheltered b. Difficult berthing and sheltered c. Easy berthing, exposed d. Good berthing, exposed e. Difficult berthing, exposed BERTHING VELOCITIES Velocity (mm/s) Displacement (tone) The berthing velocity can be calculated more precisely by using the following formulation while the ship DPT is ton ton. V 1 a Md V 1 b 1 840x Md V 1 c Md V 1 d 1 1x452 Md V 1 e Md Page 158 of 176

5 Berthing Velocities Table Md (Ton) V (a) (m/s) V (b) (m/s) V (c) (m/s) V (d) (m/s) V (e) (m/s) ) When the ships berth at the dock, the body of water carried along with the ship as it moves sideways through the water. As the ship is stopped by the fender, the momentum of the entrained water continues to push against the ship and this effectively increase its overall mass. The mass of specified water is called Added Seawater Mass, the added seawater influence coefficient is called Cm, normally calculated as the following formula: D- ; Draft L- Ship length 1 - ( =1.025t/m3) Seawater density 3) Ce Eccentricity Coefficient (Ce) In most cases there is certain angle (shown in the figure) exist when ships approach to the dock, therefore the impacting point is not opposite the center of mass of the vessel., the ship will rotate so as to dissipated partial ship impacting energy. The energy dissipated can be adjusted by Ce at berthing, the calculation formula is stated below: 1 1 1/ Page 159 of 176

6 Where r = Gyration radius of ship against axial of center of gravity on horizontal plane. I = Project of the distance between the center of gravity and berthing point on dock direction Quarter-point berthing 4 Third-point berthing 3 Mid-ships berthing 2 Ce=0.5 Ce=0.6~0.8 Ce=1 4) Abnormal Berthing Energy Abnormal impacts may occurs for various reasons - engine failure of ship, breakage of mooring or towing lines, sudden changes in weather or human error, the berthing energy will suddenly increased, it is suggested what there should be a safety factor Fs. then berthing Energy EA in abnormal berthing should be EA=FS.E, FS 2. Page 160 of 176

7 3. Fender System Selection After the effective berthing energy of ship is determined according to item 2, the selection of fender system shall be conducted in accordance with fenders performance (reaction force, energy absorption and deflection curve) which shall satisfy the following basic requirements: a. Energy absorption of selected fender system exceed effective impacting energy of ships. b. Reaction force of selected fender system is less than berthing structure allowable reaction force. c. Surface pressure of selected fender system is less than hull allowable surface pressure (to satisfy requirements by changing the sizes of front panel) d. When the ship berthing in slanting direction, the fenders will bear angular compression which resulted ix decreased energy absorption, therefore the fender performance shall be adjusted in according with the berthing angles while selecting fender system. e. The selected fender system shall be easy for installation and maintenance. f. The selected fender system shall satisfy the special requirements of adverse environment (such as high temperature, strong wind and wave etc.) and of abnormal berthing. g. The selected fender system shall be high performance/economic, free of maintenance or low maintenance ratio, that is the fender system shall be as cheap as possible in the investment, operation and maintenance procedure. 4. Fender Arrangement a. Vertical Orientation Arrangement The fender system arranged in vertical orientation shall satisfy the purpose of all types and sizes of ship berthing safely in all possible tide vary scope. The contact method of fender and ships are shown in the right figures. Page 161 of 176

8 b. Horizontal Orientation Arrangement The horizontal orientation spacing of fender depend upon the dock structure, berthing ship types and size and berthing conditions etc, the most important is to ensure the ship will not contact the structure between two fenders on normal berthing. The maximum fender spacing shall be calculated by the following formula: Where S = Max. fender spacing r = Bow radius h = Fender height in rated compression deflection The bow radius shall be determined by the following formula: 0.5 /2 /8 B- Ship Breadth L- Overall Length The equal spacing arrangement is adopted by most of the docks, the fender spacing are shown in the right table. Depth of Seawater Fender spacing along the dock 4~6 4~7 6~8 7~10 8~10 10~15 Page 162 of 176

9 Appendix Standard Size of Vessels Type of Vessel Tonnage Length (ton) DWT GENERAL CARGO & ORE CARRIER CONTAINER CARRIER OIL TANKER GAS CARRIER DWT DWT GT Breadth Depth Full draft Type of Vessel CAR CARRIER PASSENGER SHIP CAR FERRY SOIL & SAND CARRIER TUG BOAT Tonnage (ton) GT GT GT DWT DWT DWT: Dead Weight Ton (ton) GT: Gross Ton (ton) Length Breadth Depth Full draft Page 163 of 176

10 Size of Container Vessel Name of Vessel Gross Ton DWT (ton) Length Breadth Depth Draft Q ty of Containers (20 ) SL-TRADE Beishu-maru Hodaka-maru Golden Arrow Kashu-maru America-maru Hakone-mxru Kurobe-maru New York-maru Hakozaki-maru Australia-maru Togo-maru TOKYO BAY Kamakura-maru Thames-maru Hakata-maru Symbols DWT: Dead Weight Ton (ton) Wsf: Displacement Ton at full loaded condition (ton) Wsb: Displacement Ton at ballast condition (ton) Loa: Overall Length B: Breadth D: Depth df: Full draft db: Ballast AF: Area of projection of the front of ship above water line at full loaded condition AFB: Area of projection of the front of ship above water line at full ballast condition AS1F: Area of projection of the side of ship above water line at full loaded condition A1B: Area of projection of the side of ship above water line at full ballast condition AS2F: Area of ship side below the draft line at full loaded condition AS2B: Area of ship side below the draft line at ballast condition Page 164 of 176

11 A. GENERAL FREIGHTERS B. OIL TANKERS Wsf DWT Wsf DWT Wsb Wsf Wsb Wsf Log Loa log DWT Log Loa log DWT Log B log DWT Log B log DWT Log D log DWT Log D log DWT Log d r log DWT Log d r log DWT d b d f d b d f A F DWT A F DWT A FB DWT A FB DWT A SIF DWT A SIF DWT A SIB DWT A SIB DWT A S2F DWT A S2F DWT A S2B DWT A S2B DWT C. CONTAINER SHIPS D. ORE CARRIER Wsf DWT Wsf DWT Wsb Wsf Wsb Wsf Log Loa log DWT Log Loa log DWT Log B log DWT Log B log DWT Log D log DWT Log D log DWT Log d r log DWT Log d r log DWT d b d f d b d f A F DWT A F DWT A FB DWT A FB DWT A SIF DWT A SIF DWT A SIB DWT A SIB DWT A S2F DWT A S2F DWT A S2B DWT A S2B DWT E. GAS CARRIER F. CAR CARRIER Log Loa log GT Log Loa log GT Log B log GT Log B log GT Log D log GT Log D log GT Log d r log GT Log d r log GT G. PASSENGER SHIP H. CAR FERRY Wsf DWT Wsf DWT Wsb Wsf Wsb Wsf Log Loa log GT Log Loa log GT Log B log GT Log B log GT Log D log GT Log D log GT Log d r log GT Log d r log GT d b d f d b d f A F DWT A F DWT A FB DWT A FB DWT A SIF DWT A SIF DWT A SIB DWT A SIB DWT A S2F DWT A S2F DWT A S2B DWT A S2B DWT Page 165 of 176

12 GENERAL CARGO SHIP (In case of V=0.15 m/s) VESSEL DWT (ton) Loa Lpp B D d f DPT (ton) Cm BERTHING VELOCITY V (m/s) BERTHING ENERGY Ce=0.5 E (ton-m) Ce=0.7 E (ton-m) OIL TANKER (In case of V=0.15 m/s) VESSEL DWT (ton) Loa Lpp B D d f DPT (ton) Cm BERTHING VELOCITY V (m/s) BERTHING ENERGY Ce=0.5 E (ton-m) Ce=0.7 E (ton-m) Page 166 of 176

13 CAR FERRY (In case of V=0.15 m/s) VESSEL BERTHING BERTHING ENERGY DWT Loa Lpp B D (ton) d f DPT (ton) VELOCITY Ce=0.5 Ce=0.7 Cm V (m/s) E (ton-m) E (ton-m) CONTAINER CARRIER (In case of V=0.15 m/s) VESSEL BERTHING BERTHING ENERGY DWT Loa Lpp B D (ton) d f DPT (ton) VELOCITY Ce=0.5 Ce=0.7 Cm V (m/s) E (ton-m) E (ton-m) Symbols DWT: Dead Weight tonnage (ton) LOA: Overall length LPP: Length between perpendiculars B: Breadth D: Depth D f : Full draft DPT: Displacement tonnage (ton) Cm: Added mass coefficient Ce: Eccentricity coefficient Page 167 of 176

14 Front Panel Design 1. The main function of front panel is to distribute the reaction forces from fender units into the ship s hull, so the design to should be suit each individual berth. The loads and stress loads exert to front panel will depend on many factors---- the type of ship, berthing mode, characteristic of the rubber fender and tidal range etc. The design of front panel should meet the following requirements: 1.1. Resistance to bending moments and shear forces 1.2. Resistance to impact on part 1.3. There is no deflection on front panel and face pad during the compression 1.4. Suitable corrosion protection for intended environment 2. The type of the structure of front panel There are two types: open type and closed type. Regarding the open type, it is consist of steel pad, H steel and across steel.closed type are consist of steel pad, back steel and H steel. 3. The determination of the dimension of the structure of the front panel: The following requirement should be met in the design. P= (KN/m 2 ) Where P= Hull Pressure P= The sum of maximum reaction force of all fender (KN) A1= Valid width of front panel B1=Valid length of front panel Py= Hull allowable surface pressure (KN/m 2 ) Therefore if the allowable surface is known, the dimension of the front panel can be determined. Page 168 of 176

15 4. The allowed hull pressure can be obtained from the following table if it s not available in design Ship pattern Allowed hull pressure General oil tanker 250~350 KN/m 2 ULCC VLCC Coastal tanker 150~250 KN/m 2 Bulk Ship 150~250 KN/m 2 Panamax Container Ships 300~400 KN/m 2 Sub-Panamax Container Ships 400~500 KN/m 2 General cargo ship 300~600 KN/m 2 Gas Carrier 100~200 KN/m 2 Face Pads Design 1. Type There are two types of Pads: One is flat pads, the other is corner pad, which are assembled as shown in right figure 2. Specification Type Specification (length width) (mm) (Thickness 30mm or 40mm) Flat Pad etc Corner Pad etc Page 169 of 176

16 3. Material Ultra High Molecular Weight Polyethylene (UHMW-PE) or Nylon Resin are chosen as the material for face pads whose performance are shown in the following tables. Physical Performance Physical Performance Material Density Elongation at Break % Tensile Strength MPa Abrasion Rate Friction Factor Yield Strength MPa Compression Strength MPa Resistance of Shocks Kg/cm Youngs Modulus Kg/cm 2 Nylon Resin PE Resin ~ ~10500 Chain Design 1. There is three types of chains in fender system: tension chain, weight chain and shear chain. 1.1 The main function of tension chain: protect the fender from the damage while under local compression. 1.2 The main function of weight chain is to support the weight of front panel and face panel. 1.3 The main function of shear chain is to protect the fender from damage while in shear deflection. Page 170 of 176

17 2. The following items should be noted in chain design The chain dimension should be as exact as possible, not too loose or too tight The chain cannot be twisted as this reduces the load capacity Open link is preferred The initial (static) angle of the chain is important. Normally weight chains are set at a static angle of 15-25oto vertical and shear chains are set to the horizontal. Any failure will cause the chain ineffective All the chains must be with safety factors which should be 2-3 times of the work load Shackle Selection The dimension of the shackle is usually the same as the dimension of the chain, but if the shackle is required to bear the same load with the chain, then thicker shackle is preferred. Selection & Calculation of Chain Where Ø 1 = Static angle of chain (degrees) h 1 = Static offset between brackets L= Bearing length of chain h 2 =Dynamic offset between brackets at F D= Fender compression Ø 2 = Dynamic angle of chain (degrees) LW= Safe Working Load of chain (tone) µ= Friction coefficient of face pad material = 0.15 for UHMW-PE facings, typically x=combined reaction of all rubber fenders (kn) n=number of chains acting together Lb=Minimum Breaking Load of chain (tone) Fs=Factor of safety = 2~3 (typically) Page 171 of 176

18 Rubber Performance Fenders are manufactured from the high quality nature rubber and other styrene Butadiene SBR based compounds to satisfy various performance requirements. Other special rubber is also available upon customer's special requirements, the main performance index are shown as below: No. Property Testing Standard Standard Value 1 TENSILE STRENTH GB/T528,I; ASTM D412 DieC;ISO37; Din AS ;BS903.A2;JIS K6301 Item 3,Dumbell3 16 MPa 2 ELONGATION AT BREAK GB/T528,I;ASTM D412 DieC;ISO37;Din AS ;BS903.A2;JIS K6301 Item 3,Dumbell3 300% 3 COMPRESSION SET GB/T7759,I;ASTM D395;ISO815; Din (70 C,22h,20%) AS B; BS903.A6;JIS K6301 Item 10 30% 4 HARDNESS (SHORE A) GB/T531,;ASTM D2240; ISO815;Din AS ;BS903.A26;JIS K6301 Item 5A Tester DEGREE GB/T529,Crescent Test Piece; ASTM D624; ISO 5 TEAR RESISTANCE Die B 34.1;Din AS ;BS903.A3;JIS K6301 Item 9A Test Piece A 70N/mm 6 OZONE RESISTANCE (50pphm at 4 C at 20% strain at for 96 hours) GB/T13642; ASTM D1149; ISO34.1; Din AS ;BS903.A3; No cracking visible by eye 7 ABRASION RESISTANCE (Method B 1000 Revolutions) GB9867; Bx903.A9; DIN CC 8 BOND STRENGTH OF STEEL TO RUBBLE Method B HG4-854; BS903.A21 7N/mm (70O C, 96h VARIATION RATIO OF TENSILE STRENGTH GB/T3512; ASTM D412 DieC;ISO37;Din AS ;BS903.A19;JIS K6301 Item 3,Dumbell 3 20% 9 HOT AIR VARIATION RATIO AGING) OF ELONGATION AT GB/T3512;ASTM D41x DieC;ISO37;Din AS ;BS903.A19;JIS K6301 Item 3,Dumxell 3 20% BREAK Note: Other rubber performance can be manufactured upon user s request. Page 172 of 176

19 Fender Performance Testing The fender performance is determined by the absorbed energy and max. reaction force in the procedure when the fender is compressed to the rated deflection. In the performance testing procedure, the rubber fender is under direct force vertical to the fender surface, the compression speed shall be 2-8cm/min repeating three times. Unless otherwise specified, the deflection and reaction force shall be record to the nearest value to 1mm and 1.0KN (0.1ton) The unit of energy absorption is KN-m (ton-m), determined by calculation of reaction force in rated deflection/defection curve. The performance value of fender shall take the mean value of the 2nd and 3rd testing result. In the testing results, it is preferred that the energy absorption value shall be greater than the required energy absorption value with 10% deducted, the reaction force value shall be lower than the required reaction force value with 10% added. Record the in-house temperature in the testing The Tolerance of Fender Dimension The tolerance of fender dimension shall meet the following Requirements Name Length Width Height +4% +4% +4% Tolerance -2% -2% -2% 2 The dimension tolerance of bolt holes shall meet the following requirements. Name Diameter Hole Pitch Tolerance ±2mm ±4mm 3 Sampling All the taken sample, material testing, size and sampling number shall meet table 3. Tested item Material Size Specification Sample Quantity To take one set from the compound used to make fenders All the fender Take one piece in ten Re-testing In the case that the sample fail to meet the specified requirements in the material testing, two other additional samples shall be taken for testing. The selected samples shall meet specified requirements and the testing results must satisfy all requirements. In performance and dimensions testing, any sample fail to meet the requirements listed in table 2, table 3 and table 4, then sampling shall be 1 in 10 fenders (excluded the non-conformance fender). If any further sample does not satisfy the specifications, all remaining products shall be tested. Page 173 of 176

20 Unit Conversion Table VELOCITY m/s km/h ft/s mph knot 1 m/s= km/h= ft/s= mph= knot= FORCE 1=kN= kipf 1 kipf=4.449 kn ENERGY ABSORPTION 1 knm (kj) 1 knm (kj) = 1 1 tonne-m= ft.kip= AREA m 2 Inch 2 1 m 2 = in 2 = ft 2 = yd 2 = Friction Coefficient Material Friction Coefficient (µ) UHMW-PE to Steel (wet) 0.10 UHMW-PE to Steel (dry) 0.10~0.15 HD-PE to Steel 0.20~0.25 Rubber to Steel 0.50~1.00 Timber to Steel 0.30~0.50 International Steel Material Comparison List No China GB Germany DIN France NF International Japan Sweden British America Standard JTS SS BS ASTM Organization ISO 1 Q235A S235JR S235JR SS400 S235JR A570Gr Fe360A 1311 (ST37-2) (E24-2) (SS441) (E24-2).A 2 Q255A A 709M St44-2 E SM400A B Gr C45E C45E Ck45 XC48 C45E4 S45C CrMo 34CrMo4 35CD4 34CrMo4 SCM A Mn 21Mn4 20Mn5 - SBC A Cr19Ni9 X5CrNi18 10 Z6CNi SUS S H 7 X5CrNiMo Z6CND S16 0Cr17Ni12Mo2 SUS316 X5CrNiMo Z6CND a S Page 174 of 176

21 Fender System Design Condition VESSEL BERTHING CONDITION BERTH Other Requirement Maximum Vessel Minimum Vessel 1. Container Ship 1. Container Ship Note Vessel Type 2. Oil Tanker 2. Oil Tanker 3. Ore Carrier 3. Ore Carrier For other vessel please specify 4. Cargo Ship 4. Cargo Ship Gross ton G.T. Dead Weight Ton D.W.T. Displacement ton T. Length (L) m ft Width (W) m ft Depth (D) m ft Full Draft (d) m ft E Energy ton-m ft-kip Speed M/S ft/s Face Pressure ton/s 2 kip/ft 2 Safety Factor, SF Horizontal Angle Degree Vessel Flare Angle Degree Vessel Roll (+) Angle Degree Vessel max. belt size mm (eg, R200300) Soft belt or soft object Assume No if not filled Low Contact YES NO Berthing Method 1/4 POINT OR OTHER CONTINUOUS WHARF NEW WHARF CONCRETE OPEN STYLE Structure DOLPHIN EXISTING WHARF STEEL GRAVETY FLEXIBLE PILE Tidal Level-H.W.L m ft Tidal Level-H.W.L m ft Structure Elevation-Zenith m ft Structure Elevation-Nadir m ft Fender Spacing m ft Allowed R.F. tf kips kn Max. Projection m ft Specified Fender (If any) Note: The specifications and types of our company s products stated in the catalogue are for reference only, and are subject to change without advice. May customers kindly please understand us, and the specifications and types of the ordered products should in accordance with our company s final designing drawing. Page 175 of 176

22 RUBBER FENDER Page 176 of 176