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The contents of this report reflect the views of the authors, who are responsible for the factsand accuracy of the data presented herein. The contents do not necessarily reflect the officialpolicy of the Department of Transportation.

The metric units reported are those used in common practice by the persons interviewed.They have not been converted to pure SI units because in some cases, the level of precisionimplied would have been changed.

The United States Government does not endorse products or manufacturers. Trademarks ormanufacturers names appear herein only because they are considered essential to thedocument.

The publication of this document was sponsored by the U.S. Federal Highway Administrationunder contract number DTFH61-99-C00005. awarded to American Trade Initiatives, Inc. Anyopinions, options, findings, conclusions, or recommendations expressed herein are those ofthe authors and do not necessarily reflect those of the U.S. Government, the authors parentinstitutions, or American Trade Initiatives, Inc.

This report does not constitute a standard, specification, or regulation.


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Technical Report Documentation Page1. Report No.

FHWA-PL-01-018 2. Government Accession No. 3. Recipients Catalog No.

4. Title and Subtitle

Steel Bridge Fabrication Technologies in Europe and Japan5. Report Date

March 2001 6. Performing Organization Code

7. Author(s) Krishna Verma, Karl Frank, William Wright, Ronald Medlock,Bill McEleney, Pat Loftus, Bob Kase, Hardy Campbell, Alex Wilson, JohnFisher, Kathleen Lineham, Milo Cress, Ralph Anderson, Arun Shirole,Dennis Mertz, Jerry Uttrachi, Randy Sathre, Jim Hamilton

8. Performing Organization Report No.

9. Performing Organization Name and Address

American Trade InitiativesP.O. Box 8228Alexandria, VA 22306-8228

10. Work Unit No.(TRAIS)

11. Contract or Grant No.DTFH61-99-C-0005

12. Sponsoring Agency Name and Address

Office of International ProgramsOffice of PolicyFederal Highway Administration

U.S. Department of Transportation

13. Type of Report and Period Covered

14. Sponsoring Agency Code

15. Supplementary Notes FHWA COTR: Donald W. Symmes, Office of International Programs

16. Abstract The objective of this scanning tour was to conduct a broad overview of newly developed manufacturingtechniques that are in use abroad for steel bridge fabrication and erection. The trip focused on the role of steelproduction, design, innovation, and fabrication in modern steel fabrication facilities in Japan, Italy, Germany,and the United Kingdom. The team also shared information on U.S. practice, initiatives, and research activitiesin these areas.

As a result of the review, the team identified six high-priority areas on which the U.S. industry should focus:computer aided drawing and computer aided manufacturing; automated recording of inspection, weldingvariables, and geometric measurements for quality control and virtual assembly; high-performance steels andcoatings; cutting and joining steel components, members, and structures; certification and contracting of steelfabrication and erection; and design innovation.

Within each of these areas, the team made recommendations for further research, pilot studies, andmodifications to existing procedures that will further modernize structural steel fabrication facilities in theUnited States.

17. Key Words

Computer aided drawing, computer aidedmanufacturing, high-performance steel,numerically controlled, weathering steel, roboticwelding, computer integrated manufacturing.

18. Distribution Statement

No restrictions. This document is available to the publicfrom theOffice of International ProgramsFHWA-HPIP, Room 3325US Dept. of TransportationWashington, DC 20590

[email protected]

19. Security Classif. (of this report)

Unclassified 20. Security Classif. (of this page)

Unclassified 21. No. of Pages

64 22. Price

Free Form DOT F 1700.7 (8-72) Reproduction of completed page authorized


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St eel Br i dge Fa br i c at i onTech nol ogies in

Eur ope an d JapanPr epa r ed by t h e st u dy t ou r t ea m

a nd

Am erican Trad e Initiatives, Inc.&

Avalon Integra ted Services, Inc.

for the

Federal Highway Administrat ionU.S. Depa rtm en t of Tran spo rtation

M arch 2001

Krishna VermaFHWA

Karl FrankUniversity of Texas, Austin

William Wright

FHWA

Ronald M edlockTexas DO T

Bill M cEleneyNSBA

Pat LoftusHigh Steel Structures, Inc.

Ralph AndersonIllinois DO T

Arun ShiroleNSBA

Dennis M ertz

University of Delaware

Jerry UttrachiESAB

Randy SathrePDM Bridge

Jim HamiltonUtah Pacific Bridge

Bob KaseHigh Steel Structures, Inc.

Hardy CampbellAmerican Welding Society

Alex Wilson

Bethlehem Lukens Plate

John FisherLehigh U niversity

Kathleen LinehanFHWA

M ilo CressFHWA


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ii

FHWA INTERNATIONAL TECHNOLOGYEXCHANGE PROGRAMS

The FHWAs international programs focus on meeting the growing demands of itspart ners a t the Federal, Sta te, and local levels for a ccess to informa tion on st a te-of-the-art technology and the best practices used worldwide. While the FHWA isconsidered a world leader in highway transportation, the domestic highway

community is very interested in the advanced technologies being developed byother countr ies, as well as innovative organizational and f inancing techniques usedby the FHWAs international counterparts.

INTERNATIONAL TECHNOLOGY SCANNING PROGRAM

The Int erna tiona l Technology Sca nnin g Pr ogram a ccesses a nd evalua tes foreigntechnologies and innovations that could signif icantly benefit U.S. highwaytransportation systems. Access to foreign innovations is strengthened by U.S.participation in the technical committees of international highway organizationsand through bilateral technical exchange agreements with selected nations. The

program has undertaken cooperatives with the American Association of StateHighway Transportation Officials and its Select Committee on InternationalActivities, and the Transportation Research Boards National Highway ResearchCooperative Program (Panel 20-36), the private sector, and academia.

P riority t opic a rea s a re joint ly determined by t he FH WA a nd its pa rt ners. Team s ofspecialists in the specific areas of expertise being investigated are formed and sentto countr ies where signif icant advances and innovations have been made intechnology, management practices, organizational structure, program delivery, andfina ncing. Team s usua lly include Federa l an d St a te highw a y officials, priva te sectorand industry association representatives, as well as members of the academiccommunity.

The FHWA has organized more than 40 of these reviews and disseminated resultsna tionw ide. Topics have encompa ssed pavement s, bridge const ruct ion a ndmaintenance, contracting, intermodal transport, organizational management,winter road maintenance, safety, intelligent transportation systems, planning, andpolicy. Findings are recommended for follow-up with further research and pilot ordemonstration projects to verify adaptability to the United States. Informationabout the scan f indings and results of pilot programs are then disseminatednationally to State and local highway transportation off icials and the private sectorfor implementation.

This program has resulted in signif icant improvements and savings in roadprogram technologies and practices throughout the United States, particularly inthe areas of structures, pavements, safety, and winter road maintenance. Jointresearch and technology-sharing projects have also been launched withinternational counterparts, further conserving resources and advancing the stateof the ar t .

For a complete list of Int erna tiona l Technology S cann ing t opics, an d t o order freecopies of the reports, please see the last page of this publication.

Website : ww w.in terna t ional . fhwa .dot .govEma il : in terna t ional@fhwa .dot .gov


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FHWFHWFHWFHWFHWA INTERNAA INTERNAA INTERNAA INTERNAA I NTERNA TIONAL TECHNOLOGY EXCHANGE REPORTSTIONAL TECHNOLOGY EXCHANGE REPORTSTIONAL TECHNOLOGY EXCHANGE REPORTSTIONAL TECHNOLOGY EXCHANGE REPORTSTIONAL TECHNOLOGY EXCHANGE REPORTS

InfrastructureGeotechnical Engineer ing Pract ices in Canada and EuropeGeotechnologySoil NailingInt erna tional Contr a ct Administra tion Techniques for Quality E nha ncement-CATQEST

PavementsE uropean Aspha lt TechnologyEuropean Concrete TechnologySouth African P a vement TechnologyH ighwa y/Commercial Vehicle Int era ctionRecycled Materials in European Highway Environments

BridgesEuropean Br idge StructuresAsian Br idge StructuresBr idge Main tenance Coat ingsEuropean Practices for Bridge Scour and Stream Instability Countermeasures

Advan ced Composites in Bridges in Europe a nd J a panDurability of Segmental and Cable Stayed Bridges in Europe

Planning and EnvironmentEur opean Int ermoda l P rograms: P lann ing, Policy a nd TechnologyNational Travel SurveysRecycled Materials in European Highway Environments

SafetyPedestr ian a nd B icycle Sa fety in E ngland , Germany an d the Nether lan dsSpeed Ma na gement a nd E nforcement Technology: E urope & Aust ra liaSa fety Ma na gement P ract ices in J apa n , Austra l ia , an d New Zeala ndRoad Safety AuditsFinal ReportRoad Safety AuditsCase StudiesIn novat ive Tra ffic Control Technology & P ra ctice in E uropeCommercia l Vehicle Sa fety Techn ology & Pra ctice in E uropeMethods and Procedures to Reduce Motorist Delays in European Work Zones

OperationsAdva nced Tra nsport a t ion TechnologyEu ropea n Tra ff ic MonitoringTraffic Management and Traveler Information SystemsE uropea n Wint er Service Technology

Snowbreak Forest Book Highway Snowstorm Countermeasure Manual(Tr anslat ed fr om J apanese )

Policy & InformationEmerging Models for Delivering Transportation Programs and ServicesAcquiring Highway Transportation Information from AbroadHandbookAcquiring Highway Transportation Information from AbroadFinal ReportIn ternat ional Guide to Highway Transpor ta t ion Information

Also available on the internet

Only on the internet a t www.international.fhwa.dot.gov


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CONTENTSOVERVIEW ........................................................................................................................... vi

Purpose ................. ................ ................. ................ ................. ................ ................. ....... vii

Sponsoring Organizations ........................... ............................. ............................ ....... viii

Team Members ............... ................ ................ ................ ................. ................ .............. viii

ORGANIZATIONS AND SITE VISITS................ ............... ................ ................ ................ . 1

Japan .............. ................ ............... ............... ................ ............... ............... ................ ....... 1

Italy ................................................................................................................................... 8

Germany ................ ................ ................ ................. ................ ................. ................ ......... 9

United Kingdom ............................................................................................................ 10

SUMMARY OF SCAN FINDINGS ...................... ............................ ........................... ....... 13

High-Priority Topics ................ ................. ................ ................. ................ ................ .... 13

CAD/CAM.............................................................................................................. 13

Automated Recording ............... ................ ............... ................ ................ .............. 13

High-Performance Steel (HPS) and Coatings ..................................... .................. 13

Cutting and Joining................................................................................................. 13

Certification and Contracting................................................................................ 14

Design Innovation ................................................................................................... 14

Lower Priority Topics ......................... ........................... ........................... ..................... 14CAD/CAM .................................................................................................................... 14

Automated Recording .............. ................. ................ ................. ................ ................. .. 15

Fabricated Elements Virtual Assembly .................................................... ........... 15

Nondestructive Inspection .............. ................ ................ ................. ................ ...... 16

High-Performance Steels and Coatings .................... ..................................... ............. 17

Introduction .............. ................ ................ ................ ................ ................ ............... 17

Steel Quality and Properties ........................ .......................... .......................... ....... 17

Steel Processing................... ............... ................ ................ ................ ............... ....... 18

Weathering Steel .................... ..................... ..................... ..................... ................... 18

Coating Systems ................ ................. ................ ................. ................ ................ .... 19

Longitudinally Profiled (LP) (Tapered) Plates ...................................................... 19


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Cutting and Joining ....................................................................................................... 19

Introduction ............... ................ ................ ................ ................ ................ .............. 19

Automation .............................................................................................................. 20

Weld Processes ............... ................ ................ ................ ................ ................ .......... 21

Weld Details and Grinding ..................... ....................... ....................... .................. 24

Certification and Contracting ...................................................................................... 25

Bridge Design ................................................................................................................. 25

Introduction ............... ................ ................ ................ ................ ................ .............. 25

Japan ............... ............... ............... ................ ............... ............... ................ .............. 26

Italy ........................................................................................................................... 27

Germany ................................................................................................................... 27

United Kingdom ................ ................. ................ ................. ................ ................ .... 28

ACKNOWLEDGMENTS ................ ................ ................. ................ ................ ................. .. 29

APPENDIX A: Amplifying Questions .............................................................................. 30

APPENDIX B: Workshop Agendas .................... ....................... ...................... .................. 36

APPENDIX C: List of Documents ..................................................................................... 41

APPENDIX D: Itinerary ..................................................................................................... 45

APPENDIX E: Biographic Sketches ..................... ...................... ...................... ................. 46APPENDIX F: Technology Panel .................... ..................... .................... .................... ...... 51

APPENDIX G: NKK High Speed Rotating Arc Welding ..................... ........................ ... 53


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OVERVIEW

The focus of the trip was on the rolethat steel production, design,innovation, and fabrication have inmodern steel fabrication facilities inJapan, Italy, Germany, and the UnitedKingdom.

PURPOSE

The purpose of the scanning tour was to conduct a broad overview of newlydeveloped manufacturing techniques that are in use abroad for steel bridgefabrication and erection, as there is a need to further modernize structural steelfabrication fa cilit ies in th e Un ited St a tes. The focus of th e tr ip wa s on th e role tha tsteel production, design, innovation, and fabrication have in modern steelfabrication facilit ies in Japan, I taly, Germany, and the United Kingdom. In addition,the team shared information on U.S. practice, initiatives, and research activities topromote innovative steel bridge fabrication; erection techniques and high-performance steel production; and schemes to retrofit older steel structures.

The teams review concentrated on the following general topics:

C om pu t er a id ed dr a w in g (C AD )and computer aidedma nufa cturing (CAM).

Au t om a t ed r ecor din g of

inspection, welding variables, andgeometric measurements forquality control and vir tualassembly.

H i gh -per for m a n ce s t eels a n dcoat ings .

C ut t in g a n d join in g st eelcomponents, members, ands t ruc tu res .

Cer t if ica t ion a nd con t r ac t ing of s teel fab r ica t ion a nd e rect ion .

D esign in nova t ion .

These topics are discussed in detail in a separate section of this report.Recommendations are provided for the findings in each of these topic areas ascandidates for implementation into U.S. practice, and for further study anddevelopment .

Before the tr ip, the team developed a list of amplifying questions and submitted itto the organizations that were visited in each country. The list of questions servedto define the focus of the scanning tour, provided the basis for discussions, as wellas elicited responses from many of the organizations that were visited. The list of

questions is provided in appendix A.

In addition to the discussions held during the tour, the team participated in twow orkshops. One wa s held in Osaka a nd w a s organ ized by Prof. Chit oshi Miki, TokyoIn stit ut e of Technology, and Mr. Ka zuhiro Nishika wa , J a pa n P ublic Works ResearchInstitute, Ministry of Construction. The program for this workshop is listed inappendix B.


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A second workshop was held at The Welding Institute (TWI), in Cambridge, UK,a nd w a s orga nized by Drs. J ohn H a rrison a nd St ephen Mad dox. The progra m a lso islisted in appendix B.

Appendix C contains a list of the documents provided before or during the tourthat which were reviewed for the preparation of this report. Appendix D is theitinerary for the scanning tour.

SPONSORING ORGANIZATIONS

The scanning review was conducted under the auspices of the Federal HighwayAdministrations (FHWA) Office of International Programs. The National SteelBridge Alliance (NSBA) and the American Iron and Steel Institute provided inputduring the initial planning stages.

TEAM MEMBERS

The team members and the agencies and organizations they represented are listed

below.NAME RE P RE S E NTI NG ORG ANI ZATI ON

Krishna K . Verma (C ha ir ) F H WA FH WA, Wa shington , D CRa lph E . Anderson AAS H TO I llinois D OTH a rdy C a mpbell AWS Amer ica n Weld ing S ociet yMilo C ress F H WA FH WA, Lincoln , NEJ oh n W. F is her (R epor t er ) L eh ig h U n iv er sit y L eh ig h U n iv er sit yKar l H . F rank (Repor te r) Un iver s ity of Texas Un iver s ity of Texas , Aus t inJ a mes H a milt on NS B A U ta h P a cific B ridgeRober t K a se NS B A H igh S t eel S t ruct ures

K a t h leen Lineha n F H WA FH WA, Wa sh ingt on , D CP a t Loftus NS B A H igh S t eel S t ruct uresWillia m McE leney NS B A Na t iona l Steel B ridge Allia nce, RIRon a ld Med lock AAS H TO Texa s D OTD enn is Mer t z AIS I U n iver sit y of D ela w a reRa ndy S a t hre NS B A P D M B ridge, Wa usa u, WIArun S h irole NS B A Na t iona l Steel B ridge Allia nce, RIJ er ry U t t r a ch i AWS E S ABAlexa nder D. Wilson AI S I B et h lehem S t eel C orp.Willia m J . Wrigh t F H WA FH WA, McLea n, VA

Appendix E provides biographical information on the team members, and AppendixF lists their contact information.

Appendix G contains a diagram of high speed rotating arc welding.


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ORGANIZATIONS AND SITE VISITS

Background information on the organizations visited and a summary of theiroperations is provided below in this section. Details of the relevant informationlearned during the meetings and specif ic recommendations of the scanning teamare provided in the section on findings.

JAPAN

In J a pan, th e tea m visited four bridge fabrication shops. In th e great er Osaka a rea,the team visited Matsuo Bridge Company and the Yokogawa Bridge Corporation,met with corporate and plant personnel, and toured the fabrication facilit ies. Thetea m t hen visited the NK K B ridge Works, in Tsu, an d K aw a da Indust r ies, Inc., inMa ruga me, on t he isla nd of Shikoku.

The t eam tr a veled from Tsu t o Nag oya to visit th e second Tomei Highw a y project ofJ a pan Highw ay P ublic Corpora tion, specif ica lly, the I na be River B ridge on-sitef ield welding and nondestructive inspection.

Following the site tours, a one-day workshop was organized by Prof. Miki and Mr.Nishikaw a . The w orkshop was convened a t the U.S. Consulat e in Osaka .

Ma tsu o B ridge Compan y, Lt d., is one of J a pa ns leading fa bricat ors (in th e top 10)and erectors of steel structures for bridges and steel-framed buildings. Thecompan y w a s established in 1925 a nd ha s plant s in Sa kai (Osaka ), Chiba, a ndSha ngha i, China. The Sa kai plant wa s constr ucted in 1963 a nd occupies a land a reaof 86,000 m 2. P roduction capa city is 3000 metric tons per mont h. It s 225-m-long a nd51-m-wide wharf allows it to erect blocks up to 7000 metric tons, which can beshipped directly from the wharf. The plant is qualified to construct major bridges inJ a pan a nd is IS O 9001 certif ied. Mat suo has fa brica ted components for severalbridges for the Honshu-Shikoku Bridge Authority (HSBA), and for numerous

projects in North a nd S outh America , Asia, a nd t he Middle Ea st.

In general , the fabr icat ion pract ice a t the Sa kai p lan t wa s s imilar t o that of manylarger operations in the United States. Numerically controlled (NC) marking andcutting was carr ied out with gas and plasma arc cutting machines. Flux-core arcwelding (FCAW) is the dominant process (65 to 70 percent), followed by solid wiregas metal arc welding (GMAW) (100 percent), CO 2 (20 percent), and submerged arcwelding (SAW) (10 percent).

The following were observed during the visit:

Imp lemen ta t ion o f CAD/CAM technology.

N C pla s ma c ut t in g a n d m a r kin g ma ch in es .

F lange panel f ab r ica t ion line au tomat ic t a ck and fina l CO 2 weldingcorrecting angular distortion of ribs and flange (figure 1).

Demons t r a t ion of au tomat ic-scann ing u lt r a son ic te s t ing machine.

Demons t r a t ion o f 3-D measu r ing system for v i rtua l a s sembly.

P reassembly of s tee l p ie rs for I sh imaru B r idge, w i th th ick ben t p la tes.

Double-bevel groove welds w ith root gr ind ing ma chine (f igure 2).


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Fa b r ica t e d com pon en t s a n dpreassembled sections.

The Yokogawa Bridge Corporation is one ofJ a pans top five fa brica tors a nd erectors ofsteel structures for bridges, steel-framedbuildings, and communication towers. Thecompan y w a s esta blished in 1907 and h a splant s in Sa kai (Osaka ) a nd C hiba. TheOsaka plant was established in 1964 andoccupies a land area of 113,830 m 2.Production capacity is 5000 metric tons permonth. I t s w ha rf is 130 m long a nd 30 mwide and contained the 2000-ton, 115.1-msegment for the North Kyushu AirportConnection Bridge (figure 3).

The plant is qualified to construct major

br idges in J a pan . I t ha s the AISC Level I I Icertification for major bridges in the UnitedStates and ISO 9001 certification. The planthas fabricated components for severalbridges owned by HSBA and for bridges inNorth and Central America, Asia, and theMiddle East .

In general, the fabrication practice at theSa kai p lan t wa s s imilar t o man y largeroperations in the United States. NC

marking and cutting was with 2.5-kW and6-kW laser cutting machines, as well as gasa nd plasma a rc cutt ing. FCAW is thedominant process (74 percent), followed byS AW (11 percent ), solid w ire G MAW (10percent) , and shielded arc metal welding(SMAW) (4.6 percent).

The following were observed during thevis i t :

I m plem en t a t i on of CAD /C AM

technology. NC la ser a nd pla sm a cu tt in g a n d

marking machines.

C r a n es w it h lift in g m a gn et s t o m ovemultiple flange plates (figure 4).

Au tom a t ed fla n ge a n d w eb pa n elfabr icat ion w ith NC machines a ndrobots .

Figure 1. Flang e p an el fab rication line a t Saka i plan tof M atsuo Bridge Co., Ltd., in Japa n.

Figure 2. Doub le-bevel groove w elds w ith rootgrinding m achine at Sakai plant .

Figure 3. Yokogawa Bridge Corp.s Osaka plantwharf containing the 2000-ton, 115.1-m segment forNorth Kyushu Airport Connection Bridge in Japan.


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As sem bled com pon en t s of pl a t e a n dbox girder segments.

B o x u n it being m ea s u red for vi rt u a lerection check (figure 5).

P reassembly of 2000-ton segmen t of

North Kyushu Airport connectionbridge and f ield weld preparation(figures 3 and 6).

The NKK Corporation was founded in 1912a s J a pans f irst sea mless pipe ma nufa cturera nd is J a pans second la rgest producer ofst eel. The Tsu Works w a s foun ded in 1969as the Tsu Shipyard. In 1970, steel structureproduction w a s a dded, and in 1975 a largeoil-production platform was fabricated. Thefirst HSBA bridge order was obtained in1977, and the Tsu Laboratories wasest a blished in 1976. The t ota l Tsu Worksplan t occupies a la nd a rea of 1,820,000 m 2.The steel structures division is the mostmodern fabrication facility and is amongJ a pa ns top five fa bricat ors of steel bridges.Production capacity is 4000 metric tons permonth. Two large wharves are available forassembly and barge loading.

The pla nt , w hich is I SO 9002 cert ified, is

qualified to construct major bridges inJ a pan a nd elsewh ere in Asia, Eur ope, Northand South America, and the Middle East.

In the late 1980s and early 1990s thefacilit ies were renovated for automatedbridge production lines with laser cuttingand welding robots, using automated linesw ith CAD/CAM syst ems (see appen dix C).Three parallel buildings house theoperat ion. In the f irst , a ll pla te st ock is

cleaned and cut using gas, laser, or plasmacutting. Six-kW lasers are used for platesup t o 25 mm, a nd 3-kW las ers a re used forplates up to 14 mm. These NC-controlledunits provide precision cuts and longperiods of operation.

The plate product then moves to the twoassembly shops, which provide variousassembly lines of nine computer-integrated facilities, including 29 articulated

Figure 4. Cranes with lifting magnets move multif lang e plates at Yokoga w a p lant .

Figure 5. Box unit is measured for virtual erectioncheck at Yokogawa plant .


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welding robots equipped with the NKKhigh-speed, high-current rotating arcwelding system (see appendix G) with arcsensor seam tracking control.

The following were observed during thevis i t :

S t r uct u ra l la b or a t or y w i t h fa t i gu e t es tof welded pipe joint for bridges.

D em on st r a t ion of a u t om a t ed w a v erecord type ultrasonic inspectionsys tem.

D em on st r a t ion of su rfa ce st r es smeasurements, using a magneticanisotropy sensor.

D em on st r a t ion of a r obot w it h h ig h-speed rotating arc welding (figure 7).

S ea s id e (1 k m) ex pos ur e t es t of apartial, full-scale, seaside weatheringsteel bridge with small-scale platesamples (figure 8).

P a ra llel NC 3-kW C O 2 ga s laser cu t t inglines: one for large members (flanges,webs, tra nsverse r ibs) a nd one for sma llmembers (gusset plates, splice plates,stiffeners) (figure 9).

NC pla sm a cut t in g m a ch in e.

Tr a n s v er s e (or t h ot r op ic deck ) r ibassembly line (figure 10).

Figure 6. Preassembly of North Kyushu AirportConnection Bridge.

Figure 7. Robot demonstrating high-speed rotatingarc w elding at NKK Corp.s Tsu Wo rks plant in Japa n.

Figure 8. Seaside exposure test by Tsu Works of a partial, full-scale seaside weathering steel bridgewith small-scale plate samples.


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F u lly a u t om a t ic d rillin g lin e.

Cha mfer ing line for ho les in sp lice pla tes , gusset p la tes , and s t i ffeners .

I -sect ion g irder line (f lan ges , web, an d s t i ffeners).

B ox girder web an d f lange panel assembly line (f igure 11).

300-m 60-m 2-m exper imenta l model of the mega-f loat s t ructure .

The J a pan H ighwa y P ublic Corpora tion wa s founded in 1956 to administernationwide toll roads. The New Meishin Expressway is one of the ring-roadsaround large c it ies , such a s Na goya. J apa n H ighway P ublic Corporat ion a r rangedfor a visit to the Inabe River Bridge site, where construction of twin, box-steelcontinuous spans is under way through a joint venture of Ishikawajima-HarimaHeavy Industr ies Company (IHI) and Hitachi Zosen Corporation. Segmental boxsegments were being field welded, on site, by the joint venture. The 100-mm flangegroove welds were made by single-groove, automatic, 100-percent CO 2 G MAW. Nopreheating was used, as long as the base metal temperature exceeded 5 C. Both

Figure 9. Parallel NC 3-kW CO2 ga s laser cutting lines at Tsu Works: one for cutting larg e m em bers,for cutt ing small members.

Figu re 10. Tran sverse (ortho trop ic deck) rib asse m bly line a t Tsu Wo rks.


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manual and automatic ultrasonic testing were used to evaluate the f inishedproduct .

The following were observed during the site visit:

Demons t r a t ion of the au tomated u lt r asonic te st equ ipmen t on a ca libra tedtes t sample .

Demons t r a t ion of the au tomated equ ipment u sed to make the flange andweb groove welds.

Fabr icat ed box sect ions s tored on s i te (f igure 12).

Kawada Industr ies, Inc., was founded in 1922 as Kawada Ironworks. The Shikokuplant was established in 1973, and it occupies a land area of 264,863 m 2. Kaw ada i samong the top five fabricators of steel bridges. Production capacity is 7000 metrictons per month. Its wharf is 400 m long and is capable of supporting 3000 metrictons .

The plant is qua lified t o constr uct ma jor bridges in J a pan a nd ha s IS O 9001certification (steel bridge design, development, fabrication, and temporary

Figure 11. Box g irder w eb an d flang e p an el assem bly line a t Tsu Wo rks.

Figure 12. Fab ricated bo x sections stored on site a t Ina be River Bridg e in Japa n.


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erection). The plant has fabricated components for several bridges owned by HSBAand for bridges in Asia and the Middle East.

In general, the fabrication practice at the Shikoku plant was similar to severallarger operations in the United States. NC marking and cutting was observed withlaser, plasma, and gas computer-numerically controlled (CNC) machines. Flux-coregas shielded and metal core gas shielded welding were used in 90 percent of thework. Submerged arc welding was used for the balance of the work. Welding wascarried out with multiple-electrode welding machines for units for closed- andopen-rib orthotropic deck panels. Plate and box girder web panels had stiffenersand gusset plates welded on with CNC welding robots, which also are used in otheroperat ions .

I t was noted that about one-third of the Shikoku plant production involved bridgestructures. The other two thirds included building applications.

The following were observed during theplant visit:

I m plem en t a t i on o f C AD /C AMtechnology.

NC la ser a nd ga s cu tt in g a n dma rking ma chines .

Au t om a t ed w eb pa n el fa b rica t i onwith NC welding robots (figure 13).

20-el ect r od e G MAW w e ld in gmachine for open and closed ribwelding to orthotropic deck plates

(figure 14). N C dr illin g m a ch in es.

P r ea s sem bled un it s for fieldweld ing .

F a b ri ca t ed or t h ot r op ic d eck sect i on s(figure 15).

The scann ing review of J a pa n concludedwith a one-day workshop (see appendix B)on St eel Br idge Fa bricat ion Technologies.The J a pan ese par ticipa nt s includedrepresentatives from all of theorganizat ions tha t the team vis i ted , as wel las other attendees from universities andsteel producers. The workshop, organizedby P rof. C. Miki and Mr. K. Nishikaw a ,provided an opportunity to hear furtherresponses to ma ny of th e a mplifyingquest ions .

Figure 13. Autom ated w eb pa nel fabricat ion w ithw elding rob ots at Shikoku plant of Kaw ad aIndustries, Inc., in Japan.

Figure 14. 20-electrode GM AW w elding m achineopen and closed rib welding to orthotropic deckplates at Shikoku plant.


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ITALY

In I taly the scan team visited the fabrication facilit ies of the Cimolai companies in

the area of Pordenone. The Cimolai Group originated from the company formed byArmando Cimolai in 1947. Four factories are in the region; the one in Pordenoneoccupies a land area of 55,000 m 2. A second factory, at Polcenigo (10 km fromPordenone), occupies a land area of 130,000 m 2 . A third, at Piano (6 km fromPordenone), occupies an area of 140,000 m 2. A fourth, at San Quirino (7 km fromPordenone), occupies an area of 35,000 m 2. These pla nt s production ca pacityexceeds 3500 metric tons per month. The company is one of Italys top fabricatorsand erectors of steel structures for bridges, buildings, shelters for aircraft andmunitions, and towers for electricity and communication. The company hasfabricated and erected major highway and railway bridges in I taly, France, the UK,and the Middle East .

In general, the fabrication practice at the Cimolai plants was similar to manyoperat ions in the U nited Sta tes. Like many J a panese compan ies, Cimolai plays amore active role in field erection than do many U.S. fabricators. NC flame andplasma cutting machines were in use. Current use of FCAW and metal core GMAWwelding with tandem, twin arc, and automatic welding machines accounted forabout 30 percent of weld applications. This use was projected to increase as SMAWdecreased .

The following were observed during the plant tours:

Imp lemen ta t ion o f CAD/CAM technology.

N C g a s a n d pla s m a cu t t in g m a ch in es .

NC robot ic w eld in g.

Au tomated hand l ing and a ssembly of we lded beam members by mach inesdesigned and built by Cimolai (figure 16).

NC d rillin g m a ch in es.

Fab r ica t ed components (f igu re 17).

Figure 15. Fabricated orthotropic deck sections at Shikoku plant.


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GERMANY

In Berlin the scan team visited the FederalIns t i tu te for Mater ia ls Research andTestin g (B AM); a fa brica t ion shop, Kr uppStahlbau Berlin; two bridge sites; andPotsdam Square, the new center of Berlin.

BAM originated in 1870 when the PrussianMinistry of Commerce, Trade, and PublicWorks formed a Mechanical and TechnicalResearch Institute. In 1954, the FederalRepublic of Germany took overresponsibility from Berlin and establishedBAM to function as the national chemicaland materials technology institute. Theteam visited Department VII Safety ofStructures. Briefings were provided by

B AM, Krupp Stah lbau Ber l in , and HRA.

The team viewed the following inexperimental facilit ies:

Test s on old , r ive ted t ru ss-g irderbridge members under cyclic loading(figure 18).

H i gh -s peed t es t in g of st r uct u ra lmembers.

Weld in g of loa d ed st r u ct u r a lmembers.

Krupp Stahlbau Berlin, GmbH, is one ofGermanys medium-sized fabricators ofsteel structures for bridges and steel-framed buildings. The plant occupies anarea of 43,000 m 2 and employs 220 people.Krupp Stahlbau Berlin produces about10,000 metric tons per year, with annualrevenues of about DM90 million (US$4.5million).

The plant is qualif ied to fabricate andconstruct highway and railroad bridges inG erman y. The compan y ha s fa brica ted a nderected many bridges and buildings in theBerlin area, including the Havel RiverRailroad Bridge. NC flame and plasmacutting machines were in use. Current useof solid wire GMAW accounted for 85

Figure 16. Automa ted han dling and assem bly ofwelded beam members by machines designed anbuilt by Cimolai in Italy.

Figure 17. Fabricated components at Cimolai facto

Figure 18. Tests on old, riveted truss-girder bridgemembers under cyclic loading by BAM in Germa


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percent of the welding; the balance wasS AW.

The following were observed during theplan t tour :

I m plem en t a t i on of CAD /C AM

technology. N C ga s a n d pla s ma cu tt in g m a ch in es.

N C r ob ot i c w e ld in g (f ig ur e 19).

NC dr illin g m a ch in es.

Fa b rica t e d com pon en t s a n d a s sem blies(figure 20).

In addition, the team visited the HavelRiver Bridge, which was preassembled onsite because transport capabilit ies limited

the shipment size of components. The top flange was fabricated from three 50-mmplates in a layer, as shown in figure 21.

The team also made a site visit to the Humboldthafen Rail Bridge, which crossesthe River Spree and connects to the Lehrter Station, in Berlin. Figure 22 shows the

large-cast steel bearing connections and the tubular support structure, with caststeel nodes.

UNITED KINGDOM

In the UK, the team visited the fabrication facilit ies of Fairf ield-Mabey atCh epstow, Wa les. The compa ny da tes fr om its founding in 1849, wh en it built t heWye Railway Bridge in Chepstow. The plant occupies a land area of 170,000 m 2 a ndits production capacity is 2500 metric tons per month. Fairfield-Mabey leads the

Figure 19. NC robotic welding at Krupp StahlbauBerlin plant.

Figure 20. Fabricated components and assemblies at Krupp Stahlbau Berlin plant.


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UK, with about 80 percent of the current bridge market. The company fabricatesand erects steel structures for highway and railway bridges, offshore modules,bridge-maintenance gantr ies, and steel-framed buildings. I t has fabricated anderected ma jor h ighwa y a nd ra i lwa y br idges in E ngland , the Middle Ea st , a ndCentral and South America.

The fabrication practice at the Chepstow Plant is focused on steel plate fabricatedproducts, and steel bridges remain its core market. As was observed elsewhere onthe tour, the company plays a more active role in field erection than do many U.S.fabricators. CAD/CAM modeling a nd C NC cutt ing a nd welding ma chinery w ere inextensive use. Current use of GMAW and FCAW accounted for about 50 percent ofthe shop work, a nd S AW for t he bala nce of shop work. I t w a s noted tha t design/

Figure 21. Havel River Bridge in Germany, fabricated from three 50-mm plates in a layer, waspreassembled on si te .

Figure 22. Large-cast steel bearing connections and tubular support structure, with cast steel nthe Hum boldthafen Rail Bridg e in Germ any.


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build was growing in the UK and t hatFairfield-Mabey workers were often onmore than one team.

The following were observed during theplan t tour :

I m plem en ta t i on of C AD /C AMtechnology.

N C g a s a n d pla s ma cu t t in g m a ch in es(figure 23).

N C robot ic w eld in g.

Au t om a t ed h a n dlin g a n d a ss em bly ofwelded beam members.

N C d rillin g m a ch in es .

Fab r ica t ed components (f igu re 24).

Video of C hep stow p la n t o per a t i on s .

The Welding Institute (TWI), at Abington,was founded in 1946 and is one of theworlds largest independent research andtechnology organizations, with branchesand associates worldwide. I t is involvedwith all aspects of materials joining andrelated technologies. TWI has played amajor role in the development of design-and material-selection specif ications in theUK Bridge Rules (BS5400), for avoidingfatigue and fracture in steel bridges. A UK-U.S. Workshop on Innovation in SteelBridge Construction was organized by J.Ha rrison, M. Ogle, a nd S. Ma ddox (seeappendix B). The workshop provided anopportunity to review the amplifyingquestions from the perspectives of

designers, fabricators, and owners, as well as hear of the TWI work on laserwelding and cutting and other high-energy welding systems.

Figure 23. NC gas and plasma cutt ing machines atFairfield-Mabeys fabrication plant in Chepstow,Wales.

Figure 24. Fabricated components at Chepstowplant .


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SUMMARY OF SCAN FI NDINGS

On th e basis of the scan review of steel bridge fabrication in J a pan, I t a ly, Germa ny,and the UK, the team identif ied the following top priority implementation topics insix areas of focus.

HIGH-PRIORITY TOPICS

CAD/CAM Es ta b li sh a t a sk g roup of owner s and fab r ica t or s , poss ib ly th rough the

AASH TO/NS B A St eel Br idge Collabora tion, t o develop a document a tions t a n d a r d .

P romote developmen t o f a compute r in tegra ted manufac tu r ing (CIM)sof tware package.

Conduct a p ilot p ro ject on d ig ita l fabr icat ion shop documents in lieu of shopd r a w in g s .

Develop a s torage protocol for ach iev ing as-buil t documents .

Automated Recording

E v a lu a t e ex is t in g m ea s u r em en t t e ch n olog ies .

Exp lore f eas ib il ity of d igi ta l geomet r ic measu remen ts on f ab r ica t edcomponents for virtual assembly in lieu of preassembly.

Ca rry out a p ilot p roject , working closely with owners to ensure theirconfidence in the vir tual approach.

High-Performance Steel (HPS) and Coatings

Study a ppl icab i l ity of seas ide weat her ing s teels for U.S. mar ine

environments . P romote the use of a 50-ksi, low-carbon HP S for improved weldabi li ty and

toughness .

Cutting and Joining

Develop a workshop on gas-sh ielded welding and new methods of weld ingfor shop and f ield fabrication for fabricators and owners.

Work with FHWA and St a te depar tments of t ranspor ta t ion (DOTs), withAmerican Welding Society (AWS) Bridge Code support, to gain acceptancefor gas-shielded welding as a preapproved welding process.

Explore us ing the h igh-speed rota t ing arc technique with enhanced t rack ingfor f il let welding.

P romote the use of u l t rasonic inspect ion , with record producing capa bil ity,in lieu of radiography.

Mod i fy w eld ing-p rocedu re qua l i fica t ion r equ i r emen ts to a l low un l imi tedlife, provided an alternative, demonstrated quality program is in place.


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SUMMARY OF SCAN FINDINGS

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Certification and Contracting

Set up a t ask group , poss ib ly through AASH TO/NSBA Steel Br idgeCollaboration, to develop a Qualif ication Program for fabricators, whichallows them to be responsible for quality.

Explore incorporat ing appropr ia t e par ts o f ISO 9001 in the AISC

Cer t i f icat ion Program. Explore incent ives to ena ble a fa br icat or to accept responsibi li ty for both

fabrication and erection, to achieve optimum cost and delivery.

Design Innovation

Reexamine the des ign pract ice, FHWA direct ives , an d AASHTOspecifications related to two lines of support and fracture-critical membersin view of modern materials, joining, and quality control developments.

Suppor t na t iona l programs, such as t he AASH TO/NSBA Steel Br idgeCollaboration, to develop standard design details .

LOWER PRIORITY TOPICS

Eva lua te the Eu ropean pa in t p ract ice of applying the fina l coa t of pa in t inthe f ield after erection.

Eva luate the cos t-effect iveness of tapered p la t e for use in g irder flanges.

Conduct a p ilot p roject , working closely with owners to ensure theirconfidence in the vir tual approach.

CAD/CAM

All of the fabricators that the team visited had CAD and CAM software. These

systems also included three-dimensional (3-D) bridge modeling that can be used toverify a ssembly/field erection loca tion a nd eleva tion checks. The softw a re w a spurchased from a variety of vendors or developed in house. None of the softwarewas completely integrated, so the results of one package were manually input intothe next. In most of the shops, the data are generated by hand from designdra wings. The generat ion of a digital representa tion of the str ucture is crucial t o amodern fabrication shop. The information is used to verify the geometry input andsimultaneously produces manufacturing NC data. The CNC code can be sentdirectly to the applicable machine using a local area network. No detail drawingsare required in this modern fabrication shop. Large size drawings were rarelyma de. Sketches a re produced on a sma ll forma t, 8 .5 by 11 in, a nd a re genera llyproduced for the shop along with a cutting schedule. This is often in the form of atraveler following the work through the shop.

The U.S. practice is evolving along similar lines. Fully integrated systems areplanned, and cooperative development among fabricators was discussed.

Fairfield-Mabey uses a 3-D solid model as the source information for all CNCprograms for cutting, drill ing, and marking operations. All the data areelectronically transferred among packages. The only manual intervention is to


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apply allowances for predicted longitudinalwelding shrinkage to webs and f langes, which isdone by t he a pplica tion of a factor, rat her th a n byred ra f t ing .

As shown in figure 25, the software used by mostof the fabricators had the ability to perform avirtual assembly of pieces. This virtual assemblywas used to check for dimension errors andinterference of pieces in the assembled structure.The programs were often running on personalcomputer platforms, and modified versions ofAutoCAD were used in two shops. Procedures todocument changes that occurred during theproduction of the fabrication documents have tobe carefully considered. Tracking of thesechanges is important. In Fairfield-Mabey only one set of design drawings is allowedon the premises. All changes are documented on the drawings and placed in asingle binder with a copy to the designer or owner. Any necessary approval isrecorded in the same binder. The transfer of information from the fabricator to theowner or engineer is via fax or Internet.

Shop detail drawings are not needed in the modern automated shop. Shopdrawings no longer need to be available nor need to be reviewed by the owner. Inmany of the shops that the team visited, the submittal and approval of shopdrawings had been eliminated. This process of submittal and approval can takefrom 4 to 6 weeks up to 6 months in the United States. The elimination of shopdrawing submittal and approval by the owner speeds up the job and reduces costs.The cost to produce the drawings and review them is eliminated. Shop drawingsoffer little benefit to the shop, even though they are required by owners. In U.S.shops that have a strong record, owners may be willing to eliminate thisrequirement, if other forms of quality assurance are in place. The job must still berepresented numerically in order to program the NC equipment. Elimination of thegeneration and the approval of shop drawings could provide a signif icant savingsreduction in fabrication of the steel and also speed up the fabrication process. Thisstep requires the owner s trust and confidence in the fabricator s ability to performth e job. In J a pa n t his process ent a ils a prebid selection of qua lified shops,something that also should be undertaken on a tr ial basis in the United States.

One of the highest priority goa ls of U.S., European, a nd J a panese fabricators is

development of a CIM software package. The software would provide assemblyda ta , based on 3-D modeling a nd section dimensions, t a king into a ccount shr inkageand distortion from welding and cutting.

AUTOMATED RECORDING

Fabricated Elements Virtual Assembly

Automated recording of fabrication was employed to a limited extent by some ofthe fabricators visited. Various geometric-measurement systems were used by the

Figure 25. CAD of girder bridge and crossframes used by Fairfield-Mabey.


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Weathering steel plates are delivered inthe blasted condition with mill scaleremoved. The surface quality of all plateswas observed to be excellent. In Europe,steels are delivered without blasting.

All countries specify toughness for bridgesteels. For most service conditions, 20 ft-lb@10F to 20 ft-lb@-40F are typicalrequirements. This is similar to thetoughness requirements used in the UnitedS ta t e s .

J apa n a nd the U K a ggress ively contro lcarbon equivalent of steels to facilitate zeropreheat w elding. Whenever possible, J a panuses TMCP for this purpose. Weldingprocesses and consumables also are

selected to make this possible. The elimination of preheat is crucial if automaticand robotic welding are used.

Steel Processing

Most of the bridge steel provided in all countries is hot rolled; some is normalizedfor yield str ength betw een 35 an d 50 ksi (240 and 345 MPa ). J a pan leads t he use ofTMCP for production of 50 to 70 ksi (345 to 480 MPa) steel, when no preheatwelding is required. TMCP is also being used in some cases in Europe. The directQ/T process is somet imes u sed for t his purpose in J a pa n. The Q/T process is u sedin all countries for steels with strength greater than 70 ksi (480 MPa). The U.S.-grade HPS-70W has superior toughness properties and tighter chemistry controlstha n th e European st eels and is equivalent to the J a panese versions. In most of thecountr ies, steel is referred to by its minimum tensile strength, whereas in theUnited States, steel is identif ied by its yield strength.

Weathering Steel

All countries recognize the economic benefit of using weathering steel. Ownerspolicies vary about when and under what conditions this steel can be used. In I taly,up to 90 percent of the bridges a re wea thering st eel, and J a pan uses it for a bout 14percent of bridges. In the UK, typical usage is about 10 percent, but existingrestrictions are expected to be relaxed, which may increase proportions in the

future. Germany had a moratorium on weathering steel use that has recently beenrescinded .

J a pan is currently implement ing higher alloyed seaside wea th ering steels for usein marine environments. Three grades are in use: a 3-percent nickel version; a 1.5-percent nickel, 0.3-percent Molybdenum version; and a 1-percent copper, 1-percentnickel version. These new steels provide enhanced corrosion performance forseaside locations, and test samples are shown in figure 29. The extensive coastalregions of J a pa n provide a la rge ma rket for improved-performa nce st eels.

Figure 28. Multiple plate top flange for railroadbridge g irder in Germa ny.


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Figure 30. Mill-coated steel plate used in Japan.

J a pan also has developed w eather ing pr imersthat are applied to prevent initial stainingproblems and, possibly, enhance the formationof a s t ab le rust pa t ina . I t is unclear wha tadvantage these primers offer; they have notbeen used extensively and are under

evaluat ion. No other countr y is currently usingor evaluating similar primers.

Coating Systems

Pa inting is st il l in use in a ll count r ies, but th esystems va ry signif ica ntly. In J a pan, six-coa tsystems are used over seawater locations. InEurope, three-coat systems are more common.Most practices start with a zinc-rich primer. Inthe U K, meta llizing is used, in ma ny cases, inplace of the primer coat. Metallizing eliminates the volatile organic compound(VOC) from paints and may provide a more robust primer. Epoxy and urethanepaints are applied over the metallizedcoat ing .

In J a pan, t he pla te is received from t he millin a blasted and primed condition (seefigure 30). All other coats are applied in theshop. In Europe, the practice is to blast,prime, a nd epoxy coa t in the shop an d a pplya urethane topcoat in the field. The field-applied topcoat eliminates the need to

touch up damage that occurs duringshipping and handling.

Longitudinally Profiled (LP) (Tapered) Plates

Plates have been rolled with variablethickness along their length for use ingirder flanges. In J a pan, 16 bridges ha ve been built with ta pered f la nges in thenegative moment area over the piers (total of 2500 tons). LP plates also have beenused in limited quantities in Europe. The use of these plates is not increasingbecause of questionable economics. The economics of tapered plates is dependenton the cost of production versus the reduction in weight and the number of splicesin a girder. The variation in thickness is normally 10 to 20 percent of the thickestp a r t .

CUTTING AND JOINING

Introduction

The type of cross section of the bridge dictated the processes used in the shopsvisited. In J a pan, t he ma jority of the bridges a ppea r t o be closed steel boxes withorthotropic steel decks. Relatively thin plates, less than 15 mm thick, were used for

Figure 29. Weathering steel and primercorrosion test samples in Japan.


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most of the constr uction. Much of the plat e wa s less tha n 25 mm thick, wit hmultiple longitudinal and transverse stiffeners. Thin plate structures also wereused in G erman y a nd I ta ly. The ma ximum pla te t hickness for bridges in G erman y is40 mm .

Thick flanges were made by fillet welding together multiple thinner plates. Lasercutters were used by two of the fabricators to cut plates up to 16 mm thick. Thelaser cutters were typically used to cut detail pieces such as stiffeners. Often, themore complex cuts were made on the laser cutter with a multiple-torch machine,used to str ip out the stiffeners. Similar techniques are used in the United States,using plasma a nd oxygen-fuel cutt ing. La rge cutting t a bles, wh ich couldaccommodate a number of plates, were used. The single-head laser or conventionalcutting torch were computer controlled. Underwater plasma cutting was used inEngland to reduce distortion. Most of the plants had a marking head on the cuttingequipment, which allowed the same machine to do the marking and cutting. Theshort shipping lengths in J a pan restr icted th e shop length to 15 m or less.Consequently, many repetitive pieces and operations were required, whichbenefitted from automation.

Automation

The degree of automation varied among theshops. All shops used NC equipment andsome form of robotic welding. Automated,robotic welding was used for stiffeners inJ apa n , and a typ ical operat ion is shown infigu re 31. FC AW-G (ga s sh ieldin g) orGMAW welding were used almostexclusively to produce these automated

welds. These welding processes do notrequire separate handling of the f lux, whichreduces the complexity of the equipment,and provide a visible arc source thatenha nces t ra cking. A new, rapidly rotat ingarc was used by NKK to provide anelectrical feedback to correct the robotictracking. The robots did all the welding,including the wrapping of the weld of theend of the stiffener.

Automated straightening lines were used to straighten girder webs after weldingthe stiffeners. This straightening was done by cold bending, which is normally notused in the United States, as fabrication practice differs and automated equipmentis not often a vaila ble. Hea t str a ightening also wa s employed, but to a much lesserdegree than in the United States. A web straightening setup is shown in f igure 32.The hydraulic rams apply force to the plates through a set of heads that bear oneach side of the stiffener.

The widesprea d use of orthotr opic steel decks in J a pa n a nd, t o some extent, inEurope allowed the fabricators to develop and maintain automated (machine and

Figure 31. Robotic welding of girder web stiffener inJapan.


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robot) deck lines. The automated welding ofthe longitudinal stiffeners to the deckplate, using multi-head welders, is shown infigur e 33. The J a pa nese employedtrapezoid-shaped stiffeners, while theItalians used tr iangular stiffeners. The cold

bending of the stiffeners was performed bysubcontractors .

Weld Processes

The welding processes used in the shopswere very different from current U.S.practice. In the United States, SAW is usedexclusively by many bridge fabricators. Inmany of the shops that the team visited,SAW wa s t he lea st used pr ocess. Ta ble 1breaks down the reported use of various welding processes both in the shop andfield. Most of the automated welding was done using solid or metal cored GMAW

Figure 32. Web straightening press at NKK in Jap

L ocat io n Wel di ngProcess

Matsuo Yokogawa NKK Kawada JapanHighway

FairfieldMabey

KruppCimolai

Shop

GMAW 20% solid1.2-mm

wire

10.2% 1.2-mm solid

wire

80% all solidwire ~ 1/2-high speedrotary arc

with robots-80% Ar, 20%

CO2

50% solidcore

20% metalcored

NA 30% all 1.2-mm solid

wire

80% all solid wire, 1.2-mm,one two arc robot using up

to 385 amps on 1.2-mmwire. Semi-automaticwelders using high

deposition GMAW at 500ipm wfs with 1.2-mm wireuse both argon helium, and

CO2 shielding gas

50% solidwire, 1.2-mm

flux-cored;metal cored

on robot

FCAW 65% fluxcored, 1.5-mm wire

74.3% 1.4-mm fluxcored wire

60% flux-cored, 1.2-mm wire

30% fluxcored NA NA NA NA

SAW 10% fusedflux,

exclusively

10% SM570-fused flux,

lower-strength

bonded flux

NA NA 70% 15% 50%10.9% fusedflux,

exclusively

SMAW 5% 7% NA NA NA NA NA4.6%

Electro-slag/ gas

NA NA EGW used forweb welds,

ESW used forbuildings

NA NA NA NANA

GMAW automaticused forwebs

automaticused forflanges

automaticused forwebs



N A semi-automatic, for heavy,tubular weldments

used forwebs

Field

SAW deck platesw/ceramic

backing

deck platesw/ceramic

backing


backing


backing

NA deck plates w/ceramicbacking

deck andupper flange


backing

ESW/EGW EGW usedfor websplices

NA EGW usedfor websplices

NA NA NA NAEGW usedfor websplices

Table 1.EGW=Electrogas welding.ESW=Electroslag welding.


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or FC AW-G w elding. This t ype of w elding doesnot require separate f lux-handling equipmenta nd minimizes slag clea ning. In J a pan, 80 to 90percent of the shop welds are made usingthese processes, with similar percentages inGermany. The percentage of use in Italy and

the UK was less, but stil l in marked contrastto U.S. fabrication practice.

High deposition rates were used with 1.2- and1.4-mm wire, both flux and metal cored wires.Manua l weld ing a t fa s t w ire feeds wa s used inGermany. Most of the fillet welding observedwas single-pass welds done automatically.Butt welds were general ly made with e i thertrack welders or large welding gantr ies.

In the field, GMAW was used for verticalwelds. In Japan, fully automated GMAWvertical web splice welds, as shown infigure 34, w ere used in t he field. Inaddition, electrogas welding was also usedin the field for full-penetration vertical webwelds. Electroslag welding was not used forbridge construction.

Field welding was much more prevalenttha n in the U nited Stat es. The J apa nesewelded the complete box sections together

in the field (figure 35). This was on a bridgethat was being erected by launching, whichallows the welding to be done on landwithout the need for temporary shoring ofthe structure. Field welding also was veryprevalent in Germany. All of the floorbeams of a twin-girder railroad bridge(figure 36) were field welded to the girders.The floor beams were stubbed out from thegirders and then joined to the centersection by field welding both the web and

flanges.

Preheating of plates was not evident inmost of the fabricat ing shops. In th e UKand J apa n , the p la t es are ordered to a low carbon equivalence. Such steels, weldedwith semiautomatic or automatic processes(e.g., G MAW, SAW) elimin a t e t he n eed forpreheat. The elimination of preheat

Figure 33. Automated multiple robots at NKK inJapan.

Figure 34. Automated GMAW vert ical web weldingsetup in Jap an.

Figure 35. Welding of complete box sectionstogether in the field in Japan.


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faci l i ta ted au tomatic weld ing and decreasedfabrication costs. The U.S. Bridge Welding Code,AWS D1.5, contains an appendix that details how to determine the preheat temperature or the needto preheat that accounts for the level of hydrogenof the consumables, carbon equivalence of thesteel, the thickness of the plate, and the restraint.These provisions are seldom used in the UnitedStates. The TMCP steel plate used in Japan eliminates preheat.

Cera mic ba cking str ips w ere used both in t he f ield an d in t he shop in J a pan. The

ceramic backing strips allow the welding of one-sided butt splices. This type ofjoint eliminates the need to turn the plate and back gouge the root of weld followedby welding of the root. This is a particular advantage for field welds. All of theJ a pa nese fa bricat ors used cera mic ba cking t o field weld th e deck pla tes of boxgirders in the field. These were used withboth SMAW and GMAW welding processes.

Automat ed beam lines were used in J a pan,the UK, and I taly to fabricate beam sections.Very few, if any, rolled sections were evidentin any of the shops visited. Most of thefabrication was plate-type work, withsmaller beam sections produced by thefabricator on a beam line. An a utoma tedbeam w elder is s hown in figure 37. SMAW isused to make the web to f lange welds.Figure 38 shows a small beam section inproduction at a beam welder. These sizesections would typically be rolled shapes inthe United States .

Figure 36. Floor beam field welds in Germanrailroad bridge.

Figure 37. Autom ated b eam w elder in Italy

Figure 38. Sm all beam section produ ced in bea mline in Italy.


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Weld Details and Grinding

The scan tour encountered various means ofha ndling the intersection of welds. In J a pan,ma ny of the bridges w ere fabr ica ted wit houtcope holes. The w elds w ere a llow ed t o intersect.U se of this deta il is based on resea rch byP rofessor Miki (see a ppendix C ). The phot o infigure 39 shows a typical weld intersection on adeck section. C ope holes w ould be used in t heU nited St a tes to prevent the intersection of thewelds a nd eliminat e the lack of penetra tiontha t results from the intersection.

In some locat ions cope holes were used, a sshown in figure 40. The welds were wrappeda round the end of the stiffener w elds to sea l

th e connection, wh ich is not t he pra ctice in th eU nit ed St a tes. The U.S. pra ctice is to stop the w eldshort of the cope to prevent t he undercut of th ecope when th e weld is wr a pped.

The grinding of edges was done in all theJ a panese fabricat ion pla nts. Specializedequipment w a s used to grind the edges, a sillustrated in figures 41 and 42. In one shop,robots w ere used for g rindin g. Mr. Sh oji Ta ma i, ofYokogaw a B ridge Corp., explained tha t t hepurpose of exterior grinding is t o enha nce thecorrosion performa nce of pain ts. Ra dius edge

grinding is often requested by clients a nd, for this,specia lized equipment is used. For int eriorgrinding, Yokogawa Bridge applies a 1-mm cut,using a ma nual t ool .

Figure 39. Typical w eld intersection on deck sectionin Jap an.

Figure 40. Wrapping of welds at cope at KawadaIndustries in Japan.

Fig ure 4 1. Ed g e g rin d in g e qu ip m e nt in Ja p an . Fig u re 42 . Gro un d ed g e, a s u se d in Ja p an .


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CERTIFICATION AND CONTRACTING

All of the fabricators visited were certified in accordance with ISO 9001. Theclients accept this accreditation and do not have the expense of their owninspectors in the shops. No owners or third-party inspectors were evident in any ofthe shops. Numerous inspections were being performed, and evidence of priorinspections was noted on some pieces. A similar type of certification by U.S.fabricators could lead to an increase in quality and a reduction in cost.

In most of the countr ies, the contract with the fabricator includes both fabricationand erection of the structure. This type of contract eliminates the conflict betweenthe fabricator and erector, concerning fit-up and paint damage. This allows thefabricator to choose whether shop assembly is required and determine the mostefficient method of erection. Often, the erector is a subcontractor to the fabricator.This method of contracting should be tr ied in the United States.

Design-build-f inance-operate and transfer projects are favored in the UK. Partialpayment for material and progress typically are included in contracts for large

projects in both J a pan a nd G erman y.

BRIDGE DESIGN

Introduction

Although design was not a focal point of the scan, the trends and innovations insteel bridge design were noted and compiled. Differences between design in theUnited States and around the world exist not so much from technology orinnovation, but from differences in the local bridge-construction culture andpract ice .

Perhaps the most signif icant design-related observation of the scan team was therest of the industrialized worlds more liberal view of the importance ofredundancy. Two-girder bridges, as well as other structure types considerednonredundant and fracture critical in the United States, are not discouraged and,in fact, are used extensively as safe and cost-effective bridge designs. KawadaIndustr ies cited redundancy studies it performed to demonstrate adequateredundancy of its two-girder systems with widely spaced, mid-depth cross beams.No special design, fabrication, or inspection requirements for such bridges wereapparent. The U.S. design philosophy for nonredundant bridges should bereconsidered, based upon these observations and improvements in steel toughness.

Twin-girder railroad bridges are common in Germany. The single-cell box girder,commonly used for elevat ed roa dwa ys in urba n a reas of J a pan, w ould be classif iedas fracture critical in the United States, but has provided excellent performance.

Some other design innovations were observed. Corrugated steel webs were notedon a composite girder bridge with concrete flanges and corrugated steel web, butnot on steel bridges. Tubular steel members were seen on one monumental bridgeunder construction in Berlin, where the steel tubes formed the compressionmembers of an a rch. This bridge, at the ra ilroa d st a tion in B erlin, included uniquecast joints to enhance connection of the tubular elements (figures 23 and 43). The


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mat er ia l usa ge on th is br idge wa s in sharpcontrast to U.S. design practice. Concrete-filled steel tubes also were proposed for abullet-tr a in bridge.

The culture of steel-bridge design aroundthe world is very different from that in theUnited St at es, which resu lts in ma nydifferences in bridge design. In J a pan a ndEurope, innovation appears to be theprimary motivation, with cost-effectivenesssecondary. The absence of innovation in theUnited States should be noted andcontemplated. Foreign innovation does notnecessarily suggest that U.S. practitionersshould move in the same direction, but itdemonstrates what is possible, if cost-effectiveness can also be achieved, for the

U.S. bridge market. Consider the following design observations in the countriesvisited by the scan tour:

Japan

As discussed previously, steel bridges in Japan are substantially more costly thansteel building fa brica tion. The ra tio approa ches 3 in J a pan, w hereas t he ra tio in theUnited States is between 1.2 and 1.5, depending on the type of structure. Thus,man y pract ices in J apa n a re technical ly in teres t ing , bu t wa rran t much moreinvestigation, especially with regard to cost-effectiveness, before proposing theirimplementation in the United States. The observed design practices that differ

from U.S. practice and the cultural reasons for these practices include: Shor t f ield sect ions beca use of h ighly res tr ict ive over-the-road sh ipping

dimension restr ictions.

Cross sect ions of rela t ively th in p la t es with w elded mult ip le st i ffeners (bothtransverse and longitudinal) made possible by a high degree of automation.

U se of closed box sections alone (no tub girders), because of latera l-torsiona lbuckling experience encountered three decades ago.

Field welding for f ield splices to avoid the multiple, unsightly bolted splicesnecessitated by short f ield sections.

Use of noncomposi te concrete decks (now being rep laced in new design withcomposite decks), because of concrete durability problems in the past.

In J a pan, the team observed a n interesting design alterna tive to the intermediat ecross-frame diaphragms in wide use in U.S. girder bridges. Shallow (approximately1/4 depth), wid ely spa ced cross bea ms connected to full-depth tr a nsverseconnection plates with a moment connection perform as our cross frames, becauseof frame action, as illustrated in figure 44. Perhaps this detail could replace U.S.cross frames, which steel fabricators indicate are many times more costly.

Figure 43. Unique cast joints at a railroad station inBerlin.


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As of 1999, the J a pan ese bridgedesign specification does notinclude a fatigue limit state,although implementation offatigue specif ication provisionsis anticipated. I t is unclear how

fatigue is prevented with themultiple stiffened webs,orthotropic steel decks, andother complex welded sectionsused for bridges. Evidently, thedesign stress levels aremaintained low enough tominimize the formation offatigue cracking. Lack offatigue design provisions resultin the use of many low fatigue

res is ta n t deta i ls , whichincreases the risk of fa tigue cra cking in the future. Specia l fa tigue provisions a reused by some of the tollway authorities.

Italy

In Italy, one interesting practice that could find cost-effective application in theUnited States is a simplified approach to camber. Where possible, the camber is putinto the girder at the bolted field splices (i.e., slightly kinked field splices), withthe girder f ield sections essentially straight between the splices.

Also, in the fabrication shops of Cimolai, the team gained insight into bolted-splice

design practice. Apparently, the Europeans (the team saw bridge componentsdestined for different European countries) design for the net section alone,replacing boltholes with thicker plates. Closed web stiffeners were used on someItalian girders, as illustrated in figure 45. These closed stiffeners provide torsional,as well as displacement, restraint, therebyincreasing the buckling capacity of theplate or reducing the size of the stiffener.Corrosion may be a problem when this typeof stiffener is used on an external surfacesuch as a girder web.

GermanyThe limited time in Germany revealed oneunique design practice of using multiple,edge welded plates (up to 40 mm thick)instead of thicker plates (see figures 21 and28). This is apparently a holdover fromearlier concerns about uniform propertiesin thicker, single plates.

Figure 44. Shallow cross-beam diaphragmsobserved in Jap an.

Figure 45. Closed web stiffener used in Italy.


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The use of heavy tubular members resulted in developing large steel castings thatwere capable of connecting the multiple members that framed into the joints. Thisapplication drew upon technology being applied in large, offshore structures.

United Kingdom

The steel industry in the UK rolls relatively short plates, which results in morewelded shop splices than is typical in the United States, where longer as-rolledplates are available. This requires more butt welds and has resulted in moreautomation of the process in the UK than is in use in the United States. Steel-producer rolling practice has impacted fabrication practice in the UK.

Interestingly, elastomeric pads, which are gaining more widespread use for steelbridges in t he U nited St a tes, are not in use on steel bridges in t he U K. The U.S.experience with steel bridges that have elastomeric pads could be of interest to UKdesigners and owners, with regard to more cost-effective bearings for steel bridges.


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ACKNOWLEDGMENTS

The team wishes to thank the hosting organizations and their staffs in Japan, I taly,Germany, and the United Kingdom for their hospitality and for sharing their t imeand experience with the team members.

In J a pan , Pr ofessor C hitoshi Miki of the Tokyo Inst itut e of Technology an d Mr.Kazuhiro Nishikawa of the Public Works Research Institute provided input on thevisit, joined the team on the tour, and were responsible for organizing theworkshop in Osaka.

In addition, the scanning team acknowledges the cooperation and assistanceprovided by Mr. Tetsuzo Mohri, Mr. Isamu Miyaki, Mr. Koji Yamaguchi, Mr. RyoheiIw a ta , Mr. Shinji Ta kaba , Mr. Kazuo Oha ta , and Mr. Eric Beyer of the Ma tsuo B ridgeCompany, Ltd.; Mr. Tsunehiro Sasaki, Mr. Hiroshi Suzuki, Mr. Kousou Zenihiro, Mr.Shoji Tamai, Mr. Hirohito Kaji, Mr. Yoshihiko Mine, Mr. Suguru Kenjo, and Mr.Sh igeo Mura ta of th e Yokogaw a B ridge Corporat ion; Mr. Ta ka o Miya mur a , Mr.Shigeru Oga ya , Mr. Ta da shi Fu jioka, Dr. Osamu Ya ma moto, Mr. Masa ha ru Honda ,Mr. Toru Wa ta biki, Mr. Atsu nori Ka wa ba ta , Dr. Hisa shi I to, Mr. Na ohiro Ta ma oki,

Mr. Koji Yamada, and Mr. Kiyoharu Takahata of the NKK Corporation; Mr.Kazuyuki Mizuguchi and Mr. Makoto Nakasu of the Japan Highway PublicCorporation; Dr. Akio Kasuga of Sumitomo Construction Company, Ltd.; Mr. MinoruSa wa da of the IBI, Ea st J V; a nd Mr. Ta da ki Ka wa da , Dr. Kunikat su Nomura , Dr.Sh igeru E chigo, Mr. S. Morikaw a , Mr. Ka zum ori Ta ka da , Mr. Toshio Omura , Mr.H idenori Kondou, Mr. Shogo Ka ta oka, Mr. Sy unh ei U chida, Mr. Toshihiro Ma sui, Mr.Fumita ka Machida , Mr. Tsutomu S himura , Mr. Wa ta ru F ugimoto, Mr. Masa ha ruYoshimura , Mr. Makoto Yuda , Mr. Ta ka shi Ona a ru, Mr. Sea n J ohnstone, and Mr.Mar t in Densmore of Ka wa da Industr ies , Inc.

In I t a ly, the t eam a cknowledges Dr. Luigi Cimola i a nd t he entire Cimola i Family,Mr. Stefano Piovan, Mr. Antonio Polita, and Mr. Roberto Bassi of ConstruzioniCimolai Armando S.P.A.

In Germany, Dr. Klaus Brandes of the Federal Institute for Materials Research andTesting (BAM) a ssisted w ith th e visit to B erlin. Tha nks a re due Mr. J uergen H ertor,Ms. Rosema rie Helmerich, and Dr. Wolfga ng F loria n of B AM; P rof. Dr. J oachimLin dn er, Technica l Un iversit y, B erlin; Dr. Thoma s Kla ehn e, H RA E ngin eers; Mr.Gerd Wilhelm, DB Project, Knoten, Berlin; and Mr. Thomas Gregull and Mr. FrankMoeller, Krupp Stahlbau, Berlin.

In the UK, the team acknowledges the assistance of Dr. Peter Lloyd, Mr. GeoffreyB ooth , an d Mr. Da vid B icknell, Fair field-Ma bey Ltd.; Dr. J ohn H a rrison, Dr.

Stephen Maddox, Dr. Richard Dolby, Dr. Martin Ogle, and Dr. Owen Gorton of TheWelding In stitut e (TWI); Mr. Alan Ha ywa rd, Ca ss H ayw a rd, a nd P a rtn ers; Mr. BillRamsey, British Steel; Mr. Harold Dewsnap, Kvaerner Cleveland Bridge Ltd.; andMr. Sibdas Cha kraba rti , H ighwa ys Agency, London.


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APPENDIX A

31

(b) Are removable diaphragms used?

9. Are steel castings used for connections?

(a) What materials are used?

(b) What specifications have been developed?

II. Applications of New Materials1. How are higher-strength steels (485 MPa to 800 MPa yield strength) being

used?

(a) What are the future trends for these steels?

(b) Are a ll of the h igher-st reng th st eels produced a s TMC P or is Q/Tmater ia l a lso used?

(c) What toughness, sampling frequency, and locations are used?

2. Are tapered (thickness) plates used very often?

(a) Are there thickness-tolerance specifications?

(b) What is the availability of such plates?

(c) What is their relative cost?

3. How much weathering steel is being used versus painted steel?

(a) Are there any special fabrication requirements?

(b) Are there any improvements being made to basic weathering?

(c) What do you see as the future use of weathering steels?

(d) Are special joints and details used?

(e) Is st a ining a problem? How do you ma na ge it?

4. What is the maximum thickness of plate used in steel bridges?

(a) Are there differences for pedestrian, vehicular, and railroad bridges?

(b) Are there standard codes?

(c) Wha t is t he basis for the criter ia tha t a re used?

(d) Is toughness considered when determining thickness limits?

5. Wha t a re the a ctual levels of P a nd S used in bridges? Is calcium trea tmentused or specified on a ll bridge steels? To wha t ext ent is va cuum dega ssingused?

6. What organization(s) is responsible for writing the specifications for bridges tee l?

(a) Are steels certified to more than one specification? Is this required byth e owner? Does th is pra ctice cause fabricat ion problems?


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APPENDIX A

(b) What substitutions are allowed for steels specified in contractdocuments?

7. Who is responsible for encouraging new steel development?

8. Have advanced composite materials been used in conjunction with structuralsteel to construct bridges?

9. Is undermatched weld metal used for design and fabrication?

(a) How is it being used?

(b) What is the range of applications?

10. What use is made of stainless and clad steels in bridge structures?

11. What new steels are used for pins, bolts, and bearings?

III. Techniques for Cutting and Joining Steel Members (shop/field and field erectiontechniques)

1. What recent innovations have been developed in the areas of weldingconsumables, equipment, and processes?

(a) Are high-energy welding processes (i.e., electron beam, laser, or other) incommon use?

(b) Are high deposition rates used?

(c) Is electroslag or electrogas welding used? What are the requirements?What thicknesses?

(d) Are multiwire, sub-arc systems being used? How many wires? What typeof power?

(e) Is s olid wir e Mig/Ma g w eld permit t ed?

1. Is short circuiting welding permitted? Under what conditions?

2. Is pulsed-arc Mig welding permitted? Under what conditions?

(f) What other processes are used?

(g) Is flux-core self shielded, flux-core gas shielded, or metal core weldingused?

(h) What percentage of welds are made by these different processes?

(i) What is your planned future use?

2. What cutting systems are in common use?

(a) What is used in the field?

(b) Do you weld directly on the cut surface?

(c) Are thermal cut holes used with or without further treatment?


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3. Is automated handling of materials for assembling member elements beingused in th e shop? In th e field?

4. Are there in-process distortion controls?

(a) How does material variability influence this process?

(b) How is welding distortion predicted?

(c) What dimensional checks are used?

(d) How is drilling accounted for?

5. What cambering and heat-straightening techniques are used?

(a) Is the process automated?

(b) Where are the control points?

6. Are in-process NDT testing and monitoring techniques being used to assessweld qual i ty?

(a) How often?

(b) What statistical principles are applied?

7. What are the fit-up requirements for preassembly and construction?

(a) Are shop fit-up requirements imposed by owners?

(b) Is this a partial or full fit-up?

(c) What does the fabricator do in the shop to ensure compliance?

(d) Are computerized preassembly methods permitted?

(e) What procedures are used to ensure success?

(f) What has been your experience with this method?

(g) Are special criteria applied to horizontally curved girders?

8. Is field welding used to any extent?

(a) To what extent is the process automated?

(b) How are consumables stored on site?

(c) What processes are used?

9. How are weld procedures and personnel qualified?

(a) Are statistical methods employed?

(b) Are welders who are qualified for other applications (i.e., pressurevessels, ships) accepted for bridge work without additional qualif ication?

10. How are weld acceptance procedures applied?

(a) Are fitness for service criteria allowed?


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APPENDIX A

(b) Who is responsible for Qua lity Cont rol (QC)/Qua lity Assura nce (QA) ofthe fabrication and erection?

(c) Who develops the standard?

11. What role does automation play in the assembly and welding of orthotropicsteel decks?

12. Wha t a re th e size and length limita tions or restr ictions in fabrication? Isthis controlled by transportation or construction limitations?

13. Are structural adhesives being used to join steel components?

14. Have electrodes maintained compatibility with base metal weldability?

15. What procedures are used for plate and shape bending?

(a) What thickness and radius criteria are applied for cold bending?

(b) Do fracture toughness requirements impact these procedures?

(c) What role does the type of steel play?

16. What kind of pre- and post-welding treatments are used? What role doceramics, metal spacers, back-gouging, peening, or other improvementshave in these t reatments?

17. What percentage of field splices are bolted? What per

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