1998 detalles estructurales

7/27/2019 1998 DETALLES ESTRUCTURALES

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GUIDE FOR:

SHIPBUILDING AND REPAIR QUALITY STANDARD FOR HULL STRUCTURES DURING CONSTRUCTION

July 199 8

ABSIncorporated by Act of Legislature of the State of New York 1862

Copyright 1998ABS

American Bureau of ShippingTwo World Trade Center, 106 th FloorNew York, NY 10048 U.S.A


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Foreword

This guide contains information obtained from IACS Recommendation No. 47 ."Shipbuilding and Repair Quality Standards". In order to be consistent with ABSrequirements, some specific standards have been modified from the original. Themodified standards are indicated in the "Remarks" column of the tables, along with therule reference.


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ABS Guide For Shipbuilding And Repair Quality Standard For Hull Structures During Construction 1

1.0 Applicability

This guide provides guidance on shipbuilding quality standards for the hull structure duringconstruction.

Whereas the standard generally applies to: conventional ship types hull structures constructed from normal and higher strength hull structural steel, the

applicability of the standard is in each case to be agreed upon by the Bureau

The standard generally does not apply to the new construction of special types of ships as e.g. gas tankers structures fabricated from stainless steel or other, special types or grades of steel

Details relevant to structures or fabrication procedures not covered by this standard are to be

approved on a case by case basis of procedure qualifications and/or recognized nationalstandards.

2.0 Scope

The standard covers typical construction methods and gives guidance on quality standards for the most important aspects of such construction. Unless explicitly stated elsewhere in thestandard, the level of workmanship reflected herein will in principle be acceptable for primaryand secondary structure of conventional designs. A more stringent standard may however berequired for critical and highly stressed areas of the hull, and this is to be agreed with theBureau in each case.

It is intended that these standards provide guidance where established shipbuilding or nationalstandards accepted by the Bureau do not exist.

For use of this standard, fabrication fit-ups, deflections and similar quality attributes areintended to be uniformly distributed about the nominal values. The shipyard is to takecorrective action to improve work processes that produce measurements where a skeweddistribution is evident. Relying upon remedial steps that truncate a skewed distribution of thequality attribute is unacceptable.

3.0 General Requirements

In general, the work is to be carried out in accordance with the Rules and under the survey of the classification representative.

Provisions are to be made for proper accessibility, staging, lighting, and ventilation. Weldingoperations are to be carried out under shelter from rain, snow, and wind.

Welding of hull structures is to be carried out by qualified welders, according to approved andqualified welding procedures and with welding consumables approved by the Bureau.Welding operations are to be carried out under proper supervision by the shipbuilder.


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American Bureau of Shipping


4.0 Qualification of Personnel and Procedures

4.1 Qualification of WeldersWelders are to be qualified in accordance with 2/3 C .11of the ABS Rule Requirements for Materials and Welding. Subcontractors are to keep records of welders qualification and, whenrequired, furnish valid approval test certificates.

Welding operators using fully mechanized or fully automatic processes generally need not pass approval testing provided that the production welds made by the operators are of therequired quality. However, operators are to receive adequate training in setting or

programming and operating the equipment. Records of training and production test resultsshall be maintained on individual operators files and records, and be made available to theBureau for inspection when requested.

4.2 Qualification of Welding Procedures

Welding procedures are to be qualified in accordance with 2/3A.1.4 of the ABS RuleRequirements for Materials and Welding. The welding procedure should be supported by awelding procedure qualification record. The specification is to include the welding process,types of electrodes, weld shape, edge preparation, welding techniques and positions.

4.3 Qualifications of NDE OperatorsPersonnel performing non-destructive examination for the purpose of assessing quality of welds in connection with new construction covered by this guide are to be qualified inaccordance with the applicable Bureaus requirements or to a recognized national or international qualification scheme. Records of operators and their current certificates are to bekept and made available to the Surveyor for inspection.

5.0 Materials

5.1 Materials for Structural MembersAll Materials, including weld consumables, to be used for the structural members are to be inaccordance with Bureau approved construction plans and with the ABS Rule Requirement for Materials and Welding.

5.2 Details, Standards and Tolerance LimitsDetails, standards and tolerance limits may be found in the following Tables

Detail Table #

Fabrication And Fairness Flanged Longitudinals And Flanged Brackets Built-Up Sections Corrugated Bulkheads Pillars, Brackets And Stiffeners Maximum Heating Temperature On Surface

For Line Heating

Block Assembly

5.1 5.2 5.3 5.4 5.5

5.6


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Detail (Contd) Table # (contd) Special Sub-Assembly Shape Fairness Of Plating Between Frames Fairness Of Plating With Frames

5.7 5.8 & 5.9 5.10 5.11

Alignment Quality Standards Of Hull Structural

Components During New Construction

5.12, 5.13 and 5.14

TheBureau may require acloser construction tolerancein areas requiring specialattention, as follows:

-Regions exposed to highstress concentrations -fatigue prone area -detail design block erection joints -higher tensile steel regions

Welding Details Typical Butt Plate Edge Preparation (Manual

Welding) Typical Fillet Weld Plate Edge Preparation

(Manual Welding)

Typical Butt And Fillet Weld Profile (ManualWelding) Lap, Plug And Slot Welding Distance Between Welds Automatic Welding

5.15 and 5.16

5.17 and 5.18

5.19 5.20 5.21 5.22

Repair Typical Misalignment Repair Typical Butt Weld Plate Edge Preparation

Repair (Manual Welding) Typical Fillet Weld Edge Preparation Repair

(Manual Welding) Typical Fillet And Butt Weld Profile Repair

(Manual Welding) Distance Between Welds Repair Erroneous Hole Repair Repair By Insert Plate Weld Surface Repair

5.23 to 5.25 5.26 and 5.27 5.28 to 5.30 5.31

5.32 5.33 5.34 5.35


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Table 5.1

Flanged Longitudinals And Flanged Brackets

Detail Standard Limit Remarks

Breadth Of Flange

Compared To Correct Size

3 mm 5 mm

Angle between flange and Web

compared to template

3 mm 5 mm per 100 mm of a

Straightness in plane of flange andweb

10 mm 25 mm per 10 m


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Table 5.2

Built-Up Sections


Frames and longitudinal 1.5 mm 3 mm per 100 mm of a

Distortion of face plate d 3 + a/100 mm d 5 + a/100 mm

Distortion of girder and transverseat upper edge and flange

5 mm 8 mm per span between primary members


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Table 5.3

Corrugated Bulkheads


Mechanical bendingR 3t mm Material to be suitable

for cold flanging(forming) and weldingin way of radius

Depth of corrugation 3 mm 6 mm

Breadth of corrugation web 3 mm 6 mm

Breadth of corrugation 3 mm 6 mm

Pitch and depth of swedgedcorrugated bulkhead comparedwith correct value

h: 2.5 mm

Where it is not alignedwith other bulkheads

P: 6 mm

Where it is aligned

with other bulkheads

P: 2 mm

h: 5 mm

Where it is not alignedwith other bulkheads

P: 9 mm

Where it is aligned

with other bulkheads

P: 3 mm


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Table 5.4

Pillars, Brackets And Stiffeners


Pillar (between decks)4 mm 6 mm

Cylindrical structure diameter (pillars, masts, posts, etc.) D/200 mm

max. + 5 mm

D/150 mm

max. 7.5 mm

Tripping bracket and small

stiffener, distortion at the part of free edge

a t/2 mm max. 8 mm

Snipe end of secondary face platesand stiffeners

= 30

H =15 mm

D = 25 mm

F = 15 mm

5 mm

0 mm- 5 mm

5 mm

See Rules3/2.11.2


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Table 5.5

Maximum Heating Temperature On Surface For Line Heating

Item Standard Limit Remarks

ConventionalProcessAH32-EH32 &AH36-EH36

Water cooling justafter heating under 650 C

TCMP typeAH32-EH32 &AH36-EH36(Ceq. >0.38%)

Air cooling after heating under 900 C

Air cooling andsubsequent water cooling after heating

under 900 C (startingtemperature of water cooling to be under 500 C)

TMCP typeAH32-DH32 &AH36-DH36(Ceq. 0.38%)

TMCP typeEH32 & EH36(Ceq. 0.38%)

Water cooling justafter heating or air cooling

Water cooling justafter heating or air cooling

under 1000 C

under 900 C

NOTE:

( )Ceq CMn

6

Cr Mo V

5

Ni Cu

15%= + +

+ ++

+


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Table 5.6

Block Assembly


Flat Plate AssemblyLength and Breadth

Distortion

Squareness

Deviation of interior membersfrom plate

2.5 mm

10 mm

5 mm

5 mm

5 mm

20 mm

10 mm

10 mm

Curved Plate Assembly

Length and Breadth

Distortion

Squareness


2.5 mm

10 mm

10 mm

5 mm

5 mm

20 mm

15 mm

10 mm

Measured along thegirth

Flat Cubic AssemblyLength and Breadth

Distortion

Squareness


Twist

Deviation between upper andlower plate

2.5 mm

10 mm

10 mm

5 mm

10 mm

5 mm

5 mm

20 mm

10 mm

10 mm

20 mm

10 mm

Curved cubic assembly

Length and Breadth

Distortion

Squareness


Twist

Deviation between upper andlower plate

2.5 mm

10 mm

10 mm

5 mm

15 mm

7 mm

5 mm

20 mm

15 mm

10 mm

25 mm

15 mm

measured along withgirth


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Table 5.7

Special Sub-Assembly


Distance between upper and lower gudgeon

5 mm 10 mm

Distance between aft edge of bossand aft peak bulkhead

5 mm 10 mm

Twist of sub -assembly of sternframe 5 mm 10 mm

Deviation of rudder from shaftcenter line

4 mm 8 mm

Twist of rudder plate 6 mm 10 mm

Flatness of top plate of mainengine bed

5 mm 10 mm

Breadth and length of top plate of main engine bed

4 mm 6 mm


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Table 5.8

Shape


Deformation for the whole length 50 mm per 100 m against the

line of keel sighting

Deformation for the distance between two adjacent bulkheads

15 mm

Cocking -up of fore body 30 mm

Cocking-up of aft-body 20 mm

Rise of floor amidships

15 mm


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Table 5.9

Shape


Length between perpendiculars 50 per 100 m Applied to ships of 100m length andabove. For theconvenience of themeasurement the pointwhere the keel isconnected to the curveof the stern may besubstituted for the fore

perpendicular in themeasurement of the

length.

Length between aft edge of bossand main engine 25 mm

Molded breadth at midship 15 mmApplied to ships of 15m breadth andabove. Measured onthe upper deck

Molded depth at midship 10 mm Applied to ships of 10meter depth and above


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Table 5.10

Fairness of Plating Between Frames


Shell plate Parallel part(side & bottom shell)

4mm

Fore and aft part 5mm

Tank Top plate 4mm

BulkheadLongitudinal bulkhead

Transverse bulkhead

Swash bulkhead

6mm

6mm

6mm

8mm

300


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Table 5.11

Fairness Of Plating With Frames


Shell Plate Parallel part 2 /1000mm 3 /1000mm

Fore and aft part

3 /1000mm 4 /1000mm

Strength deck (excludingcross deck) andtop plate of double bottom

3 /1000mm 4 /1000mmTo be measured

between on trans.space (min. l = 3m)

Bulkhead 4 /1000mm 5 /1000mm

Others 5 /1000mm 6 /1000mm

l = span of frame (minimum l =3m)


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Table 5.12

Alignment


Alignment of butt weldsa 0.15t strength

a 0.2t other a 3.0 mm

Alignment of fillet welds Strength and higher tensile:

a t1/3 measuredon the median

a (5t 1- 3t 2)/6measured on theheel line

Other:a t1/2 measuredon the median

a (2t 1- t2)/2measured on theheel line

Where t 3 is less than t 1then t 3 should besubstituted for t 1 in thestandard

Alignment of fillet welds Strength and higher

tensile:a t1/3 measuredon the median

Other:a t1/2 measuredon the median


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Table 5.13

Alignment


Alignment of flange of T -longitudinal

a 0.04b strength a = 8.0 mm

Alignment of height of T-bar, L-angle bar or bulb

Primary membersa 0.15t

Secondary membersa 0.20t

3.0 mm

Alignment of panel stiffener d L/50

Gap between bracket/intercostaland stiffener

a 2.0 mm 3 mm

Alignment of lap weldsa 2.0 mm


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Table 5.14

Alignment


Gap between beam and framea 2.0 mm

Position of scallop d 75 mm

Gap around stiffener cut-out s 2.0 mm


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Table 5.15

Typical Butt Plate Edge Preparation (Manual Welding)


Square buttt 5 mmG = 3 mm

see Note 1

Single level butt t > 5 mmG 3 mmR 3 mm

= 50 - 70

see Note 1

Double bevel butt t > 19 mmG 3 mmR 3 mm

= 50 - 70

see Note 1

Double vee butt uniform bevelsG 3 mmR 3 mm

= 50 - 70

see Note 1

Double vee butt, non-uniform bevel

G 3 mmR 3 mm

6 h t/3 mm = 50 = 90

see Note 1

NOTE 1Different plate edge preparation may be accepted or approved by the Bureau on the basis of an appropriatewelding procedure specification.For welding procedures other than manual welding, see paragraph 4.2 Qualification of weld procedures


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Table 5.16

Typical Butt Plate Edge Preparation (Manual Welding)


Single vee butt, one side weldingwith backing strip (temporary or

permanent)

G = 3 - 9 mm = 30 -45

see Note 1

Single vee butt G 3 mm = 30 - 70

R 3 mm

see Note 1



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Table 5.17

Typical Fillet Weld Plate Edge Preparation (Manual Welding)


Tee FilletG 2 mm

see Note 1

Small angle fillet = 50 -70 = 70 - 90

G 2 mm

see Note 1

Single bevel tee with permanent backing G 4 - 6 mm = 30 - 45 Not normally for strength members

also see Note 1

Single bevel teeG 3 mmR 3 mm = 50

see Note 1



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Table 5.18

Typical Fillet Weld Plate Edge Preparation (Manual Welding)


Single J tee G =2.5- 4 mmr = 12 -15 mm

R = 3 mm 35

see Note 1

Double bevel tee symetrical

t > 19 mmG 3 mmR 3 mm

= 50

see Note 1

Double bevel tee assymetrical t > 19 mmG 3 mmR 3 mm

see Note 1

Double J bevel symmetrical G =2.5- 4 mmr = 12 -15 mm

R 3 mm 35

see Note 1

NOTE 1

Different plate edge preparation may be accepted or approved by the Bureau on the basis of an appropriatewelding procedure specification.For welding procedures other than manual welding, see paragraph 4.2 Qualification of weld procedures


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Table 5.19

Typical Butt And Fillet Weld Profile (Manual Welding)


Butt weld toe angle 60h 0.2R maximum h = 6 mm

Butt weld undercut D = 0 mm 0.5 mm

Fillet weld leg length s = leg lengtha = throat depth

s 0.9s da 0.9a d

over short weld lengths

sd= design sad= design a

Fillet weld toe angle 90 In areas of stress

concentration andfatigue, the Bureaumay require a lesser angle

Fillet weld undercut D = 0 mm 0.5 mm


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Table 5.20

Lap, Plug And Slot Welding


Fillet weld in lap joint b = 2t 2 + 25 location of lap joint to be approved by theBureau

Fillet weld in joggled lap joint b 2t2 + 25

Plug welding when t 12 mml = 60 mmR = 6 mm, 40 -50 G = 12 mmL > 2l

when 12 >> 12 mml = 100 mmG = 2tL = 2 l- 3l max. 250 mm


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Table 5.21

Distance Between Welds


Scallops over weld seams

d

for r 30 mmd 5 mm

Distance between two butt welds d 0 mm

Distance between butt weld andfillet weld

d 10 mm

Distance between butt welds for cut-outsd 30 mm

for margin platesd 300 mm

150 mm


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Table 5.22

Automatic Welding


Submerged Arc Welding (SAW)0 G 0.8 mm G 5 mm edge preparation as per

Table 5.15 and 5.16

SAW may follow WPSapproved by theBureau

See Note 1



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Table 5.23

Typical Misalignment Repair

Detail Repair Standard Remarks

Alignment of butt jointsStrength membersa > 0.15t 1 or a > 3 mm release and adjust

Othersa > 0.2t 1 or a > 3 mmrelease and adjust

Alignment of fillet weldsStrength and Higher tensile steelt1/3 < a t1/2 generally increase weldthroat by 10%

a > t1/2-release and adjust over a minimumof 50a

Othera > t1/2 release and adjust over a minimumof 30a

Where t 3 is less than t1 then t 3should be substituted for t 1 instandard

Alignment of flange of T-longitudinal

When 0.04b > 0.08b or 8 mmgrind corners to smooth taper over aminimum distance L=50a

Alignment of height of T-bar, L-angle bar or bulb

When 3 mm > 6 mmrelease and adjust over minimum L = 50afor primary structure and L = 30aelsewhere

Alignment of lap welds 2 mm > 5 mmmembers to be re-aligned


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Table 5.24



Gap between bracket/intercostaland stiffener

When 2mm < a 5mm weld leg length to be increased by increase in gap

When 5mm < a 10mm chamfer 30 - 40 and build up with welding

When a > 10mm increase gap to 50mm andfit collar plate

b= (2t + 25)mm, min. 50mm

Gap between beam and frame

a > 2 mm release and adjust


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Table 5.25


Detail Repair standard Remarks

Position of scallopWhen d < 75 mm, web plate to be cut

between scallop and slot, and collar plate to be fitted

OR fit small collar over scallop

OR fit collar plate over scallop

Gap around stiffener cut-out When 2mm < s 5mm weld leg length to beincreased as much as increase in gapopening over 2mm

When 5 mm < s 10 mm nib to bechamfered and built up by welding

When s > 10 mm cut off nib and fit collar plate with same height as nib

20 mm b 50mm


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Table 5.26

Typical Butt Weld Plate Edge Preparation Repair (Manual Welding)


Square butt When G 10 mm chamfer to 45 and buildup by welding

When G > 10 mm build up with backingstrip; remove, back gouge and seal weld; or,insert plate, min. width 300mm

Single bevel butt

Double bevel buttWhen 3mm < G 3t/2 mm (maximum25mm)

build up gap with welding on one or bothsides of preparation, with possible use of

backing strip as necessary, to maximum t/2.

Where a backing strip is used, the backingstrip is to be removed, the weld back gouged, and a sealing weld made

Double vee butt, uniform bevels

When G > 25 mm or 3t/2 an insert plate, of minimum width 300mm, to be welded in

place

Double vee butt, non-uniform bevel


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Table 5.27

Typical Butt Weld Plate Edge Preparation Repair (Manual Welding)

Detail Repair Standard RemarksSingle vee butt, one side weldingwith backing strip When G 25mm or G t/2 build up edge preparation

on one or both sides, grind edge preparation, weldwith backing strip, remove backing strip, back gouge,and back weld

When G > 25mminsert plate, min. width 300 mm

Single vee butt, one side welding

When 3 mm < G 3t/2 mm (maximum 25 mm) buildup gap with welding on one or both sides of

preparation, with possible use of backing strip asnecessary, to maximum t/2.

Where a backing strip is used, the backing strip is to be removed, the weld back gouged, and a sealingweld made

Single vee butt When G > 25 mm or t/2 an insert plate, of minimumwidth 300 mm, to be welded in place


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Table 5.28

Typical Fillet Weld Plate Edge Preparation Repair (Manual Welding)


Tee Fillet 2 mm < G 5mm leg length increased toRule leg + (G-2)

5 mm < G 16 mm Chamfer to 30 to 45 , build up with welding, on one side, with or without backing strip, grind and weld

G > 16 mm or G > 1.5t - new plate to beinserted (min. 300mm)

Liner treatmentt2 t t1G 2mma = 5 mm + fillet leg length

Not to be used in cargo area or areas of tensile stress

perpendicular to liner


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Table 5.29



Single bevel tee 3 mm < G 5mm build up weld

5 mm < G 16 mm - build up with welding, with or without backing strip, remove backing strip if used,

back gouge and back weld

G > 16mm new plate to be inserted of minimumwidth 300mm


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Table 5.30



Single J tee as single bevel tee

Double bevel tee symmetricalWhen 3 mm < G 16 mm build upwith welding using ceramic or other approved backing bar, remove, back gouge and back weld

Double bevel tee assymmetrical

When G > 16 mm-insert plate of minimum height 300 mm to be fitted

Double J bevel symmetrical


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Table 5.31

Typical Fillet And Butt Weld Plate Edge Preparation Repair (Manual Welding)

Detail Standard Remarks

Fillet weld leg lengthIncrease leg or throat by welding over

Fillet weld toe angle

> 90 grinding, and welding, wherenecessary, to make < 90

Short beads, less than

50mm

Microgrooves of groundedge to be parallel to mainstress direction

Butt weld toe angle

> 90 grinding, and welding, wherenecessary, to make < 90

Butt weld undercut

Where 0.5 < D 1 mm undercut to be

ground smooth (localized only)

Fillet weld undercut Where D > 1 mm undercut to be filled bywelding


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Table 5.32

Distance Between Welds Repair


Scallops over weld seams Hole to be cut and ground smooth toobtain distance


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Table 5.33

Erroneous hole repair


Holes made erroneously D < 200 mm Strength membersopen hole to minimum 75 mm dia. fitand weld spigot piece

OR open hole to over 300 mm and fitinsert plate

Fillet weld to be madeafter butt weld

The fitting of spigot

pieces in areas of highstress concentration or fatigue is to be approved

by the BureauOther membersopen hole to over 300 mm and fitinsert plate

OR fit lap plate

t1 = t2 L = 50 mm, min

Holes made erroneously D > 200 mmStrength membersopen hole to over 300 mm and fitinsert plate

Other membersopen hole to over 300 mm and fitinsertt plateOR fit lap plate

t1 = t 2 L = 50 mm, min


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Table 5.34

Repair by insert plate

Detail Repair standard RemarksRepair by insert plate

L = 300 mm minimum

B = 300 mm minimum

R = 5t mm100mm minimum

(1) seam with insert piece is to bewelded first

(2) original seam is to be released andwelded over for a minimum of 100mm

Repair of built section by insert plate

L min 300 mm

Welding sequence(1) (2) (3) (4)

Web butt weld scallop to be filledduring final pass (4)


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Table 5.35

Weld surface repair


Weld spatter 1. Remove spatter observed before blasting with scraper or chipping hammer etc.

2. For spatter observed after

blasting:a) Remove with a chipping

hammer, scraper, etc. b) For spatter not easily

removed with a chippinghammer, scraper, etc.,

grind the sharp angle of spatter to make it obtuse

In principal, no grinding isapplied to weld surface

Irregularity of manual weldWhen the surface irregularityexceeds 3mm, apply grinding untilthe irregularity becomes less than3mm

Arc StrikeRemoved the hardened zone bygrinding

1998 detalles estructurales

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