design considerations for aluminum hull structures - Ship Structure ...

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-60-SUl@!ARYAll parties contacted foresaw no insurmountable construction orfabrication problems and agreed that a satisfacto~ hull could be deliveredby implementing three basic tools:(1) Establishmentof a,ndrigid adherence toapmper welding sequence.(2) Use of good welding equipment, continuouslyma intained,(3) Use of properly trained and qualified welders with good on-linesupervision.IIE.FIRE PROTECTIONDEFINITION OF REQUIREMENTSThis phase of the stu~ evaluates the problem of providing a satisfactorylevel of fire protection for a large aluminum bulk carriers giving consideraforsteel ships, means of maintaining structuraltion to present requirementsintegri~ in the face of a fire, and methods of detecting and extinguishinga shipboard fire. References (~b) through (68),form the basis of &is stu@.Present Coast Guard Requirements - The basic document applicable to thisstudy is the U. S. Coast Guard “Rules and Regulations for Cargo and WscellaneousVesselsIJ,Subchapter 1, Part 92.07, Structural Fire Protection,excerpts of which appear in Appendix B.It must be assumed that at present, compliance with the intent of theRules is essential for certification of a U. S. Flag aluminum bulk orecarrier.The standard fire test defined in paragraph 92.07-~(a) of the Rties, isessential in the development of a fire protection system. Appendix C containsa brief history of maritime fire testing and the reasons for adoptingthe standard fire test as a means of evaluating fire resistant constructionsand materials.The hull, superstructure, structural bulkheads, decks and deckhousesare specified by the U. S. Coast Guard to be of steel construction Orjalternately, in special cases other equivalent materials. Metal equivalentto steel is defined as one which, by itself or due to insulation provided,has structural and _integri@ qualibies equivalent to steel at the end of theapplicable fire exposure. These composite structures are required to be ofllAll_oco~truction, which, when subjected to the standard fire test~ arecapable of preventing the passage of smoke and flame for one hour. Foraluminum structural equivalence to steel, it is required that the temperature oftlm aluminum shall not rise 200 degrees C abmre,ambient in the presence of ftie.In addition to the structure stated above, certain other structures arerequired to be of IIAII-OconstructiO~:(a) The bounda~ bulkheads and decks separating the accommodationsand control stations from the cargo and machinew spaceslgalleys, main pantries and storerooms> other than small servicelockers.
-61-(b)(c)Bulkheads of galleys, paint and lamp lockers and EmergencyGenerator Room.Stair towers, elevator, dumbwaiter and other trunks.In summary, it must be concluded that all aluminum structures, specifiedto be of ‘]AII-Oconstruction, must be capable of withstanding the passage ofsmoke ard flame for a period of one hour while restricting the maximumtemperahre of the aluminum to 400 degrees F.Fire Test of Aluminum Construction - An extensive test program of representativeinsulated aluminum bulkhead and deck assemblies is presently beingconducted under the auspices of the Fire Test Ad Hoc Subgroup of Task GroupHS-6-1 (Aluminum) of the Society of Naval Architects and Marine Engineers(SNAME). Reference (67) is a test report on the first bulkhead test by theNational Bureau of Standards dated June 1~, 1967. Ten additional bulkheadand ceiling configurations are now in the process of fabrication for testingduring 1970. From these tests it will be possible to establish factualcriteria for the protection of aluminum structures within the living, workingand stores spaces.In addition to the SNAME test maw smaller tests have been conductedby materials manufacturers. Unfortunately, the results of these tests areof a proprieta~ nature. However, while these smaller tests lack officialGovernment approval they do nevertheless contribute valuable informationtowar~ eventual solution of the problem of fire protective aluminumconstruction.AREAS REQUIRING PROTECTIONLiving, Working and Stores Spaces - A study has been made of the living,working and stores spaces of a steel and equivalent aluminum bulk cargo ship,similar to the MV CHALLENGER, and built in strict accordance with currentU.S. Coast Guard rules. The study included the complete after deckhousedown to and including the underside of the Upper Deck.The construction utilized to afford the required protection is basedupon tests, where available, or the construction considered most suitable atthis time, based upon past experience, pending confirmation by testmethods. In most cases, a conservative approach has been taken in order torealistically approximate the maximum additional cost and weight that mightbe required.For both steel and aluminum ships, the stateroom and living spacedivisional bulkheads and the house side lining will be identical, i.e., 7/8inch thick free standing marinite with steel “H” posts and joiner shapes withinsulation if necessary. The normal application of thermal insulation on thesurfaces of air-conditioned spaces results in an added degree of protection.ID general, the aluminum bulkheads requiring additional protection canbe grouped in the following categories:(a)(b)The exposed surfaces within stair-towers.The engine room side of the machinery casing.
Page 5:
CONTENTSI.. II.III.Iv.v.VI ●VII.I
Page 9 and 10:
LIST OF FIGURES(Cent’d)FIGURE NO.
Page 11 and 12:
I. INTRODUCTIONThis report summariz
Page 13:
art in fabricating and maintaining
Page 16 and 17:
MONTEROSSO GRANA /17VALGRANA / CARA
Page 18 and 19:
-8-Numerous references have been re
Page 20 and 21: .10.TABLE 2. Mechanical Properties
Page 22 and 23: TABLE 2 Mechanical Properties of Al
Page 24 and 25: TABLE 3 Mechanical Property Limits
Page 26 and 27: -16-l?igures5, 6, 7 ati 8 present f
Page 28 and 29: -18-ti-’”’-”-””””-L
Page 30 and 31: -20-60 .r---.— ..,.— -——,L-
Page 32 and 33: .22-each stress level, rate of load
Page 34 and 35: -24-!Z456-H321 = 0.485083-H321 = 0.
Page 36 and 37: -26-(c)Members with partial or cont
Page 38 and 39: -28-AllOyS 5083 and 54.56(~ content
Page 40 and 41: -30-The previous paragraphs have de
Page 42 and 43: -32-The problem of cargo hold abras
Page 44 and 45: -34-The question of residual stress
Page 46 and 47: .36-Each alloy was given a relative
Page 48 and 49: -38-GENERAL OBSERVATIONSFYior to a
Page 50 and 51: -40-The question of comparative imp
Page 52 and 53: -42-(d)(e)Poor quality welds due to
Page 54 and 55: -44-The ABS criteria noted above we
Page 56 and 57: -46-DNV would consider fatigue in e
Page 58 and 59: -48-is less, for the exposed side s
Page 60 and 61: Equation (2):-50-Hu1l SMa~um = Hull
Page 62 and 63: -52-Another aspect of vibrations wh
Page 64 and 65: -54-000000000Bottom Shell PlateSide
Page 66 and 67: -56-at the deck and keel. This stre
Page 68 and 69: -58-AT is the change inUT= Thermal
Page 72 and 73: -62-(c)(d)(e)(f)T~e exterior side o
Page 74 and 75: TABLE 12 Aluminum Bulk Carrier - Su
Page 76 and 77: .66-INSUT.ATION AND SHEATHINGShell8
Page 78 and 79: -68-(b)(c)(d)(e)(f)(g)(h)(i)(j)At l
Page 80 and 81: -70-IIF.INSTALLATION OF SYSTEMS AND
Page 82 and 83: Rudder Assembly -carrier should be
Page 84 and 85: -74-(b)MechanicalTensile Strength 6
Page 86 and 87: -76-(e)The steel piping must be of
Page 88 and 89: -78-Other Piping Systems and Valves
Page 90 and 91: -80-struetion for the aluminum hull
Page 92 and 93: -82-Large heavy type machine~ must
Page 94 and 95: suffers attack in an alkaline envir
Page 96 and 97: -86-REPAIRSObtaining proper repairs
Page 98 and 99: -88-The design of the midship s~cti
Page 100 and 101: -90-assuming the increase is applic
Page 102 and 103: LIGHT SHIP WEIGHT ESTIMATE-92-In or
Page 104 and 105: -94-TABLE 20 Aluminum Bulk Carrier
Page 106 and 107: TABLE 22 Trim and StabilityFull Loa
Page 108 and 109: -98-TABLE 24 Price of Steel Bulk Ca
Page 110 and 111: GaseNumber. . . -.,- .TABLE 27 Comp
Page 112 and 113: -1o2-TABLE 28CarriersComparison of
Page 114 and 115: 12 ---n..T.[T7%l,=LEGS IU ORF=ErY
Page 116 and 117: -106-such as iron ore, on two of th
Page 118 and 119: -108-7)is,zg~ gg~5e mzz~E’4E!~K2j
Page 120 and 121:
-11o-(a)(b)(c)(d)Inerting system fo
Page 122 and 123:
-112-fatigue, particularly in the p
Page 124 and 125:
-114-2k* Installation of Systems an
Page 126 and 127:
-116-LIST OF REFERENCES(7)Fatigue P
Page 128 and 129:
-11.8-LLST OF REFERENCES(Cent’d)(
Page 130 and 131:
-120-ADDITIONAL SOURCES OF INFORMAT
Page 132 and 133:
-122-redistribution of the still wa
Page 134 and 135:
-124-APPENDIX BEXCERPTS FROMRULES A
Page 136 and 137:
-126-92.07-10(d)(~) Interior stairs
Page 138 and 139:
-128-~gE1+0102030- .. ..—405060
Page 140 and 141:
ectintyclassification4KEYWORDSROLEL
Page 142:
SHIP STRUCTURE COMMITTEE PUBLICATIO
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