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Mentoring Part V: More than a Saying
Australia and New Zealand
Raymond K. RyanPhone: 61-2-4862-3839Fax: 61-2-4862-3840
Croatia
Prof. Dr. Slobodan KraljPhone: 385-1-61-68-222Fax: 385-1-61-56-940
Russia
Dr. Vladimir P. YatsenkoPhone: 077-095-737-62-83Fax: 077-093-737-62-87
INTERNATIONAL SECRETARIES
In several previous issues of WeldingInnovation, starting in 1996, a four-partseries on mentoring in the engineeringprofession was published (and is noweasily accessed on our new web site at
www.WeldingInnovation.com. ) As acontinuation on that theme, I would liketo share with you my experiences in amentoring relationship.
It has been a real privilege to have notonly one, but two excellent mentors tohelp me jump-start my professionalcareer. Both Omer Blodgett and DuaneMiller have outstanding reputations in the structuralwelding industry. What has made the greatest impres-sion on me on a daily basis are the little sayings andillustrations that they both use to explain concepts andexpress ideas. At first glance, these comments mayseem to be only catchy clichs. However, these quotesare more. They are words to live by golden nuggetsof truth to help guide us like road signs along lifes high-way. These power phrases are at the heart of ourmentoring relationship. The very word mentor means atrusted counselor or guide a coach!
One example of Duanes sayings is what are thefacts? I can deal with the facts; just give me the facts.This may seem like an obvious request from a supervi-sor, and it is. But the principle behind the statement is
much larger than the question. When faced with a newchallenge or a difficult situation, what do you do? Howshould you respond? As we learned in our first under-grad engineering class, before you can solve any prob-lem you need to clearly define it. You need the facts!Decisions are easier and situations are more manage-able when we get to the facts. I am learning that disas-ters can be handled if you understand the facts. Thisbit of wisdom has helped me to be able to focus andsolve problems more quickly.
Omer also has plenty of sage advice, and one of myfavorite examples is his philosophy of dont design with
your heart! This is another variation on the get to thefacts principle. In our design seminars, Omer tells astory of a young engineer (and no, it was not me!) who
was challenged to reduce the deflection ofan accelerating steel component on apiece of equipment. The engineer decidedto use aluminum rather than steel toreduce the weight. However, in this exam-
ple the change to aluminum did not solvethe problem because he never addressedthe real issue deflection. Yes, the densi-ty was decreased to one-third that of steel,but the modulus also changed to one-thirdthat of steel, and nothing was accom-plished to reduce deflection. Omer callsthis designing with your heart. The ideais simple yet profound: take time to ratio-
nally think through a problem and minimize your assump-tions. In other words, get to the facts and use mathemat-ics and engineering to make the decisions for you. Dontdesign with your heart!
Other examples that I have picked up are Dont solve one problem by creating another. One plus one doesnt necessarily have to equal two,
but it better be close. Under-promise and over-deliver.
These sayings are so important to me because they allcontain a lesson, a principle that can be applied in manyareas of life, both technical and non-technical.
Both of my mentors have shared with me the benefits of
sales experience to building a career. I am now about tofollow their advice and their example. After the first of theyear, I will be transferring to the Houston office of LincolnElectric and will not be directly involved with the James F.Lincoln Arc Welding Foundation or Welding Innovationforthe next couple of years.
My parting message to our readers is simple: please con-sider sharing the wealth of your experience by creatingone or more meaningful mentoring relationships. And ifyou are in a mentoring position already, whether it is for-mally defined or unspoken, I encourage you to considerteaching through your own power phrases. Believe me,
the impact can be long-lasting and dynamic!
Scott Funderburk, P.E.Assistant Editor, Welding Innovation
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1Welding Innovation Vol. XVIII, No. 3, 2001
Cover: This chemical tanker, named forthe opera composer Verdi, was one of sixbuilt by the Shipyard K. Damen of
Rotterdam, the Netherlands, featuringcargo tanks fabricated of duplex stainless
steel. See story on page 2.
The views and opinionsexpressed in WeldingInnovation do not neces-sarily represent those ofThe James F. Lincoln ArcWelding Foundation or TheLincoln Electric Company.
The serviceability of aproduct or structure utiliz-ing the type of information
presented herein is, andmust be, the sole responsi-bility of the builder/user.Many variables beyond thecontrol of The James F.Lincoln Arc WeldingFoundation or The LincolnElectric Company affect theresults obtained in applyingthis type of information.These variables include,but are not limited to, weld-ing procedure, plate chem-istry and temperature,weldment design, fabrica-tion methods, and service
requirements.
Volume XVIIINumber 3, 2001
Editor
Duane K. Miller,Sc.D., P.E.
Assistant Editor
R. Scott Funderburk, P.E.
The James F. LincolnArc WeldingFoundation
Omer W. Blodgett, Sc.D., P.E.
Design ConsultantFeatures
Departments
Visit us online at www.WeldingInnovation.com
6 Design File: Designing Welded Lap Joints
9 Opportunities: New Welding Innovation Web SiteLincoln Electric Professional Programs
2 TankersA Composition in Duplex StainlessDuplex stainless steel is increasingly used in shipbuilding,due to its high yield strength and corrosion resistance.
10 Engineering for Rehabilitation of Historic Metal Truss BridgesA structural engineer investigates the feasibility of rehabilitating century-oldmetal truss highway bridges for pedestrian service.
16 Artistic PrecisionWelders at an Ohio metalworking firm collaborate with a Kenyon College
art professor to realize his artistic vision.
THE JAMES F. LINCOLN ARC WELDING FOUNDATION
Dr. Donald N. Zwiep, ChairmanOrange City, Iowa
John Twyble, TrusteeMosman, NSW, Australia
Roy L. MorrowPresident
Duane K. Miller, Sc.D., P.E.Executive Director & Trustee
R. Scott Funderburk, P.E.Secretary
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2 Welding Innovation Vol. XVIII, No. 3, 2001
TankersA Composition in Duplex Stainless
By Fred Neessen
Piet BandsmaLincoln SmitweldEindhoven, the Netherlands
IntroductionDuplex stainless steel is finding anincreasing frequency of application inthe shipbuilding sector, mainly due toits high yield strength and corrosionresistance properties. The design andfabrication of a recent chemical tankerproject illustrates the trend.
The ship owner Gesellschaft furOltransport (GEFO) of Hamburg,Germany, contracted the Shipyard K.Damen of Rotterdam, the Netherlands,
to build six ships designed for bothinland and seagoing navigation, fea-turing cargo tanks fabricated of duplexstainless steel. The resulting double-hull tankers, designed by GEFO totransport up to 2,750 tonnes (2700tons) or 3,250 m3 (4,250 yd.3) of liquidin twelve separate tanks, are 95 m
(312 ft.) long and 6.35 m (21 ft.) highwith a 12.5 m (41 ft.) beam. The sepa-rate cargo tanks allow fully indepen-dent loading and emptying, permittingthe simultaneous transportation of dif-ferent chemicals. On an interestingnote, each ship was named for afamous musical composer: Rossini,Puccini, Verdi, Bellini, Mozart, andDonizetti.
Choice of Material
The cargo tanks were fabricated ofduplex stainless steel (WNr 1.4462),which has a higher alloy content thanthe austenitic AISI 316LN grade oftenused in the construction of similarinland navigation tankers. The higheryield strength and superior corrosion
resistance of duplex stainless gov-erned the choice of the material.These two properties increased thenumber of different chemical productsthat can be loaded and transported bythe tankers. While the ultimate tensilestrength of WNr 1.4462 is approxi-mately 20 percent higher than that of316L, its yield strength is 120 percenthigher. Since European shipbuildingcodes are based on yield strength, nottensile strength, WNr 1.4462 was par-
ticularly attractive in this application.Furthermore, the lower nickel contentof WNr 1.4462 made it a more eco-nomical choice for this application thaneither 316LN or 317LN.
Another factor taken into considerationwas the resistance of the base materi-
The higher yield strength
and superiorcorrosion resistanceof duplex stainlessgoverned the choice
of material
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Welding Innovation Vol. XVIII, No. 3, 2001 3
al to pitting corrosion, as expressed bythe Pitting Resistance Equivalent orPRE. The PRE may be expressed withor without the influence of nitrogen(N), as shown in the following formula:
PRE(N) = %Cr + 3.3 * %Mo (+16 * %N)
This formula clearly shows that molyb-
denum (Mo) makes an important contri-bution to pitting resistance. The higherthe PRE number, the higher the resis-tance to pitting and crevice corrosion.
Specific comparisons of the mechani-cal properties and chemical composi-tions of the three grades of steel areshown in Tables 1 and 2. To sum up,the duplex stainless was chosen forreasons of economy, high strength,and excellent resistance to both chlo-ride corrosion cracking and pitting cor-rosion. The materials high yield
strength translated to reduced platethickness and reduced weight, whichreally means increased cargo carryingcapacity.
Process andConsumable Selection
For both CrNi and CrNiMo stainlesssteels, any conventional weldingprocess can produce welds of opti-mum quality, provided that the correctwelding parameters are maintained,
and that the correct consumables areused. For this chemical tanker project,Shipyard K. Damen considered thetotal cost of various processes, includ-ing the costs of any necessary pre-and post-weld treatment, before decid-ing to use a combination of GMAW,FCAW and SAW. Welding positions,base material combinations, and theselection of welding processes andconsumables were all decided inaccordance with Germanischer Lloydrules. Lincoln Smitweld provided tech-
nical support and assistance withdevelopment of the welding proce-dures, process and consumablesselection, welder qualification and test-
UNS AISI Yield (MPa) Tensile (MPa) A4 (%)
S 31653 316LN 205 515 40
S 31753 317LN 240 550 40
S 31803 DSS (1.4462) 450 620 25
UNS AISI C max. Cr Ni Mo N min. max. average
S 31653 316LN 0.030 16 - 18 10 - 14 2 - 3 0.10 - 0.16 24.2 30.5 27.3
S 31753 317LN 0.030 18 - 20 11 - 15 3 - 4 0.10 - 0.22 29.5 36.7 33.1
S 31803 (1.4462) 0.030 21 - 23 4.5 - 6.5 2.5 - 3.5 0.08 - 0.20 30.5 37.8 34.2
Arosta 4462 A5.4: E 2209-16* EN 1600: E 22 9 3 N L R 3 2 0.02 0.8 1.0 22.5 9.5 3.2 0.16 3055
Arosta 4462-145 A5.4: E 2209-16* EN 1600: E 22 9 3 N L R 5 3 0.025 0.7 1.0 22.5 9.5 3.0 0.16 3055
LNM 4462 A5.9: ER 2209 EN 12072: G 22 9 3 N L 0.018 1.5 0.5 22.7 8.5 3.0 0.15
Cor-A-Rosta 4462 A5.22: E 2209T0-4 EN 12073: T 22 9 3 N L R M 3 0.03 0.9 0.6 22.9 9.3 3.4 0.14 40
Cor-A-Rosta P 4462 A5.22: E 2209T1-4 EN 12073: T 22 9 3 N L P M 2 0.03 0.7 0.6 22.9 9.2 3.4 0.14 40
LNS 4462 A5.9: ER 2209 EN 12072: S 22 9 3 N L 0.03 0.9 0.7 22 8 3.0 0.15 3050
P 2000 - EN 760: S A AF 2 6 3 DC
Cor-A-Rosta 309L A5.22: E 309LT0-1/4 EN 12073: T 23 12 L R C/M 3 0.03 1.4 0.6 24 12.6 - 15
Cor-A-Rosta P 309L A5.22: E 309LT1-1/4 EN 12073: T 23 12 L P C/M 2 0.03 1.2 0.6 23.3 12.6 - 15
Table 1. Mechanical properties of base materials according to ASTM A 240.
Table 2. Chemical composition of base materials according to ASTM A 240.
Table 3. Duplex stainless welding consumables.
Base material Chemical compositionPitting Resistance Equivalent
%Cr + 3.3 * %Mo (+ 16 * %N)
Product AWS classification EN classification C Mn Si Cr Ni Mo N FN
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4 Welding Innovation Vol. XVIII, No. 3, 2001
ing, and welder training. The weldersneeded training and qualification (t&q)on duplex stainless steel as well as onwelding of dissimilar materials joints.
Pulsed gas metal arc welding wasused to create a root run in a V-60joint in the vertical down position on aceramic backing strip. The shieldinggas employed was a three partArHeCO2 blend.
Stainless flux cored electrode account-ed for most of the welding of thetankers. The Lincoln Smitweld Cor-A-Rosta range of products was used,as follows:
Cor-A-Rosta 4462 was employed fordownhand welding of grooves andhorizontal-vertical fillets. Shieldinggas selections include 100% CO2,as well as 80% Argon + 20% CO2.
Cor-A-Rosta P 4462 was employedfor out-of-position welding. Theshielding gas is restricted to 80%Argon + 20% CO2.
The use of stainless steel flux coredelectrode offered the following advan-tages over solid electrode:
Weldable using conventionalMIG/MAG power sources
Wide current setting 30% higher deposition rate Smooth bead surface
As 5-6 and 7
Fewer undercuts and less oxidationof adjacent areas
Less spatter; less post-weld cleaning Better wetting properties Out-of-position welding capability Less expensive shielding gas
(Ar + CO2 or 100% CO2) High operator appeal
The materials high yield
strength translatedto reduced plate thickness
and reduced weight
Figure 1. Schematic cross section of a chemical tanker.
Reference No.(fig. 2)
MaterialWeldingposition
Weldingprocess
Welded joint Testing
1
2
3
4
5
6
7
8
9
10
11
12
Duplex / Duplex
Duplex / Grade A
Duplex / Duplex
FCAW(P 4462)
SAW
FCAW(P 4462)
FCAW
(P 309L)
GMAW + FCAW
Double fillet
weld throat = 4 mm
I-joint (square)
1/2 V-50 incl. fillet weld
V-60with ceramic backing
Double filletweld throat = 4 mm
V-60
Dye checkHV10 Fracture
As 5-6 and 7
Dye check HV10
X - Ray CorrosionFerrite Mechanical
Dye check HV10
Fracture
Table 4. Overview of welding methods.
PB (2F)
2PD (4F)
PA (1G)
PB (2F - 2G)
PA (1G)
PF (3G up)
PA (1G)
PB (2F) manual
PB (2F) machined
PD (4F)
PF (3F up)
PG + PF (3Gd + 3Gu)
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Welding Innovation Vol. XVIII, No. 3, 2001 5
Submerged arc welding, althoughoffering very high productivity, is usuallylimited to welding in the flat position.Because of this, its use on this projectwas limited to the butt weld joining ofsheets. Cor-A-Rosta 4462 wire and aneutral flux were selected for the SAWprocess.
Manual metal arc welding was employedin those areas of the fabrication thatcould not be welded with mechanizedprocesses. The covered electrodesselected were Arosta 4462 and Arosta4462-145 (145% efficiency). Tack weldswere made using Arosta 4462 (without
high efficiency).
For further details of welding methods,consult Table 4, with its referenceskeyed to Figure 1.
Testing
Fillet welds were given Vickers hard-ness and fracture tests as prescribedby Germanischer Lloyd (GL) rules.
Butt welds were subjected to mechani-cal tests per GL rules, as follows: Vickers hardness Ferrite content measured with
Magne Gage Reduced-section tensile test Root and face bend tests Impact test: center line weld, fusion
line and fusion line + 2 mm (0.08 in.)Charpy samples
Butt welds were also corrosion-testedin accordance with GL rules, which forchemical tankers require:
Intergranular corrosion attackaccording to DIN 50914. There wereno defects.
ASTM G48 method A during 24hours @20 22 - 23C (68 72-73F). No pitting was observed.
Figure 2. Actual view of the layout of the tanks.
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6 Welding Innovation Vol. XVIII, No. 3, 2001
Designing Welded Lap JointsPractical Ideas for the Design Professional by Duane K. Miller, Sc.D., P.E.
Design File
Welded connections involve two components that are bothunder the direct control of the designer: the joint type, andthe weld type. Failures in or near the weld may be theresult of an improperly designed joint. In this Design File,
the principles that should be applied when designing lapjoints are presented.
Superficially, a lap joint looks very simple, and it may seemodd that this plain configuration of material would need tobe carefully considered. The complication stems from thefact that loads do not instantaneously transfer from onemember to another. The three joints in Figure 1one buttjoint, and two lap jointsshow the differences in the flowof stress through the two joints. The butt joint includes agroove weld while the lap joints use fillet welds. The differ-ence is, stress flow is more associated with the joint type,as opposed to the weld type. The resultant differences in
stress distribution result in the need for rules to proportionthe lap connection components.
Forces applied to the ends of lap joints result in eccentricloads in the connection area. This can cause joint rotation,as illustrated in Figure 2. This same eccentricity can causethe root of a fillet weld to tear when only one transversefillet is applied to a lap joint that is permitted to deflectlaterally, as can be seen in Figure 3.
In summary, the simple lap joint inherently offers two broadchallenges to the designer:
1. How to deal with the non-uniform stress distribution, and2. How to deal with the eccentricity.
While many welded applications are not contractually gov-erned by AWS D1.1 Structural Welding CodeSteel, thedesigner of any product can find helpful provisions in thatcode that address these conditions.
A
B
C
Figure 1
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Welding Innovation Vol. XVIII, No. 3, 2001 7
Non-Uniform Stress DistributionD1.1 paragraph 2.14.1 requires that, when longitudinal filletwelds are used alone (such as in figure 1c), the length ofthe fillet weld shall be no less than the perpendicular dis-tance between them. This is illustrated in Figure 4. Eventhough the weld length L may be acceptable for the trans-fer of force F, the complicated stress flow pattern of Figure4b will generate unacceptable stress concentrations.
The Code goes further in paragraph 2.14.1 and requiresthat the distance between the welds (shown as D inFigure 4) be no greater than 8 in. (200 mm) if only longitu-dinal welds are used (as shown in Figure 1c). For dis-tances greater than 8 in. (200 mm), transverse welds orintermediate plug or slot welds are permitted to overcomethis restriction. While the code does not specifically identifythe option, bolts could also be used to accomplish thisfunction.
Paragraph 2.32.1 in Part C for Cyclically Loaded (i.e., sus-ceptible to fatigue failure) Connections additionally requires
that this distance not exceed 16 times the thickness of thethinner member, and gives the following reason for theneed for the intermediate plug or slot welds: to preventbuckling or separation of the parts. Such separation wouldstrain the root of the longitudinal fillet welds, and couldlead to tearing. In cyclic loading, it could lead to fatigue fail-ure, initiating from the weld root.
The role of the 16 times plate thickness would only beapplicable for material less than 1/2 in. (12.5 mm); other-wise, the 8 in. (200 mm) requirement from paragraph2.14.1 would govern.
Eccentric Loads
D1.1 requires that at least two lines of longitudinal or trans-verse welds be applied to lap joints (paragraph 2.4.8,2.4.8.1). This eliminates the concerns shown in Figure 3.There is a caveat: this requirement does not apply whenthe joint is sufficiently restrained to prevent it from openingunder load (paragraph 2.4.8.1). Whatever the externalrestraint, if rotation is prevented, the concerns of eccentric-ity are eliminated.
To prevent the condition illustrated in Figure 2, paragraph
2.4.8.2 requires a minimum overlap of five times the thick-ness of the thinner part, but not less than 1 in. (25 mm).Double fillet welds in lap joints with proper overlap is suffi-cient to prevent such rotation.
If restrained, the five times overlap provision does notapply. Any sufficient restraint is acceptable, and this isconceptually illustrated in Figure 5.
Figure 2
Before loading
After loading
Figure 3
Figure 4
Before loading
After loading
A L > D Acceptable
L < D Not acceptableB
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8 Welding Innovation Vol. XVIII, No. 3, 2001
Other IssuesThe code also provides requirements for the details of thefillet welds that are typically used in these connections. Forexample, the fillet welds are to terminate not less than thesize of the weld from the start of the extension (paragraph2.4.7.2). See Figure 6. This is primarily a workmanshipconcern. Carrying the weld out to the end of the part(where there is little material to conduct away the heat of
the weld) often leads to undercut, or melting away of theedges, creating a weak spot in the lapped attachment.
Often, the lap joint lends itself to welds being applied oneither side of the joint. Illustrated in Figure 6, the codedescribes this as welding on opposite sides of a commonplane, and in paragraph 2.4.7.5, requires that the weldsbe interrupted at the corners. Again, this is to avoid under-cut and unacceptable melting of the edges.
The provisions of paragraph 2.4.5 also apply to lap joints.This provision restricts the maximum fillet weld size to thethickness of the base metal for material less than 1/4 in.
(6 mm) thick, and for heavier material, to the thickness ofthe part less 1/16 in. (2 mm), unless the weld is designatedon the drawings to be built out to obtain full throat thick-ness. See figure 7. This is to avoid the situation where anothin weld can be generatedthat is, a weld thatappears to be full size, but in fact lacks the required weldthroat. (See Design File, Welding InnovationVol. XVI,Number 1, 1999.)
The selection criteria for longitudinal versus transverse filletwelds could consider the increased allowable strengthassociated with the transverse option, reducing therequired size (see Consider Direction of Loading WhenSizing Fillet Welds, Vol. XV, No. 2, 1998). While thisoption will result in a higher allowable strength, it comes atthe cost of reduced ductility in the weld. The ductility of theconnected material, typically the point where inelasticstrains are designed to be concentrated, would beunchanged with either weld orientation.
Conclusion
Superficially, detailing a lap joint and the corresponding weldsmay seem simple, but a variety of important details need tobe considered. The following checklist may be helpful:
Are the parts sufficiently restrained to prevent jointrotation? If not, use at least two rows of welds.
Is the overlap at least five times the thickness of thethinner part? And, is it at least 1 in. (25 mm)?
For longitudinal welds, are they at least as long as thedistance between them?
For lap joints with only longitudinal welds, is the distancebetween the welds less than 8 in. (200 mm)? For cycli-cally loaded members, is this distance also less than16 times the thinner member?
For material thicknesses of 1/4 in. (6 mm) or more, has thefillet weld leg size been reduced by 1/16 in. (2 mm)?
Have the fillet welds been detailed to terminate at leastone weld size from the end of the piece? Are they
detailed to avoid tying the welds together on oppositesides of the common plane of contact?
One final note: these provisions are intended to be appliedto lap joints designed to transfer stresses between mem-bers. For situations involving lap joints but where the jointis more associated with the assembly of a member, andnot with transfer of calculated forces, the principles pre-sented above are not necessarily applicable.
Figure 5
Figure 6
Figure 7
Weld restrained by a force, R
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Welding Innovation Vol. XVIII, No. 3, 2001 9
Blodgetts Design of Welded Structures
April 16-18, 2002
September 24-26, 2002
Blodgetts Design of Steel Structures is an intensive 3-dayprogram which addresses methods of reducing costs,improving appearance and function, and conserving materialthrough the efficient use of welded steel in a broad range ofstructural applications. Seminar leaders: Omer W. Blodgettand Duane K. Miller. 2.0 CEUs. Fee: $595.
Blodgetts Design of Weldments
June 4-6, 2002
October 29-31, 2002
Blodgetts Design of Steel Weldments is an intensive 3-dayprogram for those concerned with manufacturing machinetools, construction, transportation, material handling, andagricultural equipment, as well as manufactured metalproducts of all types. Seminar leaders: Omer W. Blodgettand Duane K. Miller. 2.0 CEUs. Fee: $595.
Fracture & Fatigue Control in Structures:Applications of Fracture Mechanics
October 15-17, 2002
Fracture mechanics has become the primary approachto analyzing and controlling brittle fractures and fatiguefailures in structures. This course will focus on engineeringapplications using actual case studies. Guest seminarleaders: Dr. John Barsom and Dr. Stan Rolfe. 2.0 CEUs.Fee: $595.
Space is limited, so register early to avoid disappointment.For full details, see
http://www.lincolnelectric.com/knowledge/training/seminars/
Or call 216/383-2240, or write to Registrar, ProfessionalPrograms, The Lincoln Electric Company, 22801 SaintClair Avenue, Cleveland, OH 44117-1199.
Now you have instant access to great design and technicalinformation about arc welding at our new James F. LincolnArc Welding Foundation web site!
As many of our readers know, Welding Innovationhasbeen available online for several years via The LincolnElectric Company web site. Now, for the first time, you willbe able to download the latest edition or view back issuesof Welding Innovationon its own site! You can also updateyour mailing address or request a free subscription by visit-ing our Subscriber Services section.
You will also have access to information about the historyof the Foundation, a huge list of technical papers, andinstructions about entering one of our Award Programcontests. Whether youre a welder, engineer or a student,theres a contest for you with cash prizes available. Thedetails are online, so what are you waiting for?
One more thing Textbooks and other publications are alsonow available for purchase on our secure Internet server.
Lincoln Electric Professional Programs
Opportunities
Announcing
www.WeldingInnovation.com
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10 Welding Innovation Vol. XVIII, No. 3, 2001
Engineering for Rehabilitation
of Historic Metal Truss Bridges
By Frank J. Hatfield, P.E.Professor Emeritus, Civil andEnvironmental Engineering
Michigan State UniversityEast Lansing, Michigan
Editors Note: An earlier version of thispaper was presented at the 7thHistoric Bridges Conference in
Cleveland, Ohio, in September 2001,and was published in the proceedings
of that conference.
Introduction
The Calhoun County Historic BridgePark southeast of Battle Creek,Michigan, displays a collection of reha-bilitated metal truss bridges for useand enjoyment by pedestrians. Fromthe perspective of a structural engi-neer, it was instructive to investigatethe general feasibility of rehabilitatingcentury-old metal truss highwaybridges for pedestrian service consis-tent with modern standards for safe-ty1,2,3 and historic integrity14.Engineering aspects of rehabilitationare discussed for bridges that are nowin the Park, specifically:
133rd Avenue bridge (Figure 1), apin-connected half-hip Pratt ponytruss spanning 64 ft. (19.5 m), erect-ed in 1897 by the Michigan BridgeCompany to cross the Rabbit Riverin Allegan County, Michigan.
Twenty Mile Road bridge (Figure 2),a 70 ft. (21 m) long riveted Pratt ponytruss that spanned the St. JosephRiver in Calhoun County. Physicalfeatures hint that this bridge wasdesigned for railway service. Thebuilder has not been identified andseveral sources date construction tothe early twentieth century.
Gale Road bridge, a pin-connectedskewed Pratt through truss built in1897 by the Lafayette BridgeCompany. Originally spanning 122ft. (37 m) over the Grand River inIngham County, Michigan, thisbridge currently is being re-erectedin the Park.
Six other bridges have been procuredand are awaiting rehabilitation beforebeing put in the Park, including thesethat also will be discussed
Tallman Road and Bauer Roadbridges, nearly identical pin-connect-ed Pratt through trusses thatspanned about 90 ft. (27 m) over theLooking Glass River in ClintonCounty. Manufactured by the PennBridge Company and erected in1880, they are two of Michigansoldest through trusses9.
Charlotte Highway bridge, manufac-tured by the Buckeye Bridge
Company and erected in 1886. Priorto its recent removal (Figure 3), itcrossed the Grand River in IoniaCounty with a span of 177 ft. (54 m)and was one of very few double-intersection Pratt truss bridgesremaining in Michigan9.
FeasibilityInvestigation of feasibility involvescomparing historic and modern specifi-cations for bridge design, particularly
those governing materials and loads.During the period when the projectbridges were built, standards werepromulgated by individual iron andsteel producers, bridge designers andmanufacturers, owners (typicallymunicipal governments) and textbookauthors. These standards were numer-ous and varied; those cited are repre-sentative rather than comprehensive.
Figure 1. The rehabilitated 133rd Avenue bridge, installed at the CalhounCounty Historic Bridge Park.
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Welding Innovation Vol. XVIII, No. 3, 2001 11
Strength of MetalsAlthough the quality of structural steelhas been perfected over the past cen-tury, the strength of low carbon steelsusually used in bridges has notchanged significantly (Table 1).However, the allowable stresses usedby bridge designers increased as con-
fidence and understanding developed.This is reflected in the trend towardlower factors of safety illustrated byTables 1 and 2. Early bridge designersused factors of safety as high as six tocompensate for lack of quantitativeinformation. Today, based on results ofa century of research and experience,factors of safety of two or less are typ-ical. Modern specifications may allowlarger stresses in the old steel andwrought iron members of a historicbridge than did its designer.
Live Load
An old highway bridge may havebecome deficient in strength due tothe increased weight of trucks. In 1916Waddell17 advocated designing ClassC bridges for a single 6 ton (53 kN)truck weight, and Class A bridges foran 18 ton (160 kN) truck, noting thatAlmost all of the old highway bridgesare incapable of carrying these newlive loads with safety. The smallest
design vehicle load currently recog-nized is a two-axle truck weighing 15tons1 (133 kN). However, historicmetal highway bridges were designed
to carry uniformly distributed loads inaddition to, or in lieu of, concentratedaxle loads to assure safety for lines ofwagons or automobiles, livestock, andcrowds of people, the latter being thelarger, or governing, distributed load.
Table 3 traces the trend and variationsin design values for distributed liveloads on highway bridges as well as
listing current design values for pedes-trian bridges2. Ranges reflect levels ofservice. This table demonstrates that,in general, the published design loadsfor old highway bridges exceed thecurrent requirement for pedestrianbridges. Bridges with long spans anddesigned for rural service may beexceptions.
Wind LoadIn contrast to distributed live loads,design wind loads have increased sig-nificantly. In 1901 Waddell advocateddesign loads of 250 and 150 lb/ft.(3.65 and 2.19 kN/m) on the loadedand unloaded chords, respectively, forclass A bridges with spans of 150 ft.(46 m) or less16, but by 1916 he had
Modern specs may allowlarger stresses in the members
of a historic bridgethan did its designer
Figure 2. The rehabilitated Twenty Mile Road bridge, shown in its new position
at the Historic Bridge Park.
Figure 3. Lifting the Charlotte Highway bridge from its original abutment. Thisend was lowered onto a barge prior to hauling the bridge across the river andup the other bank.
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12 Welding Innovation Vol. XVIII, No. 3, 2001
increased those values to 320 and180 lb/ft.17 (4.67 and 2.63 kN/m). TheIllinois Highway Department designedfor the larger of 25 lb/ft.2 (1.2 kN/m2)on the vertical projection of each trussand of the deck, or 300 and 150 lb/ft.(4.38 and 2.19 kN/m) on the loadedand unloaded chords, respectively12.Modern specifications1,2 are muchmore demanding, requiring design forwind loads of 75 lb/ft.2 (3.6 kN/m2) on
the vertical projection of each trussand of the deck, plus 300 and 150lb/ft. (4.38 and 2.19 kN/m) on theloaded and unloaded chords, respec-tively (this lineal load is not requiredfor pedestrian bridges), plus 20 lb/ft.2
(0.96 kN/m2) upward on the deck.Clearly, historic bridges are unlikely tohave been designed for the wind loadscurrently mandated.
Structural Analysis and Design
The components of each of the reha-bilitated project bridges were analyzedto estimate design stresses associatedwith internal forces caused by speci-fied combinations of loads1 and actingon the original uncorroded membercross-sections. Allowable stresseswere computed from assumed materi-al properties3 and specified factors of
Table 1. Tensile strengths of steel and factors of safety for tension fracture at net section.
Table 2. Tensile strengths of wrought iron and factors of safety for tension fracture.
Source
Pottsville Iron
& Steel Co.7
Carnegie Phipps
& Co.7
IATM10
Waddell16
Burr and Falk4
Copper12
Michigan13
Bethlehem Steel Co.7
Waddell17
Ketchum12
AASHTO3
AASHTO1
1887
1889-18931900
1901
1901
1909
1910
1907-11
1916
1920
pre 1905
1905-36
current
YearGrade of
Steel
Yield stress,minimum,
ksi(MPA)
Ultimate stress,minimum,
ksi(MPA)
Allowable stresson net section,
ksi(MPA)
Factor ofsafety forfracture
for bridgesmedium
medium
medium
medium
moving loads
medium
medium
ASTM A36
35 (241)
35 (241)
30 (207)
35 (241)
26 (179)
30 (207)
36 (248)
60 (414)
60 (414)
60 (414)
60 (414)
52 (358)
60 (414)
58 (400)
15.6 (108)
12.5 (86)
16 (110)
18 (124)
10 to 25 (69 to 720)#
15 (103)
12.5 (86)
16 (110)
16 (110)
26 (179)*
30 (207)*
29 (200)*
3.8
3.3
3.5 to 6.0@
2.4 to 6.0#
4.0
3.8
2.0*
2.0*
2.0*
* for inventory rating # depending on service class and influence area
Source
Carnegie Kloman & Co.7
Waddell15
Phoenix Iron Co.7
IATM11
Waddell16
AASHTO3
1873
1883
18851900
1901
Year Grade of Steel
Yield stress,minimum,
ksi(MPA)
Ultimate stress,minimum,
ksi(MPA)
Allowable stressksi
(MPA)
Factor ofsafety forfracture
wrought iron
iron
refined iron
test iron class A
test iron class B
stay-bolt iron
wrought iron
wrought iron
26 (179)
25 (172)
25 (172)
25 (172)
25 (172)
26 (179)
50 (345)
48 (331)
48 (331)
50 (345)
46 (317)
50 (345)
14 (97)
8 to 12.5 (55 to 86)#
12 (83)
13 (90)
14.6 (101)*
3
4.0 to 6.2#
3.8
* for inventory rating, less than 100,000 load cycles@ depending on span # depending on type of load, including impact factor
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Welding Innovation Vol. XVIII, No. 3, 2001 13
safety1. For each component and loadcombination, the allowable stress wasdivided by the design stress. A ratioless than unity indicates need for mod-ification, while a ratio greater thanunity suggests that an acceptable levelof safety may be achieved withoutcompletely restoring corroded sections(in general, significant damage wasrepaired in the interest of historicintegrity and esthetics). The threerehabilitated project bridges werefound to have adequate capacity forpedestrian loading.
Unusual Features
The structural analysis of a truss usu-ally is a routine procedure. To simplifycomputations, the structural engineerassumes that each member transmitsforce only in the direction of its longitu-dinal axis. That is, the member is not
subject to transverse force (shear) orbending. This assumed behavior isachieved if the members are straightand connected at their ends by friction-less pins, longitudinal axes of membersare concentric at connections, andloads are applied to the truss only atconnections. Real trusses conform tothis idealization only approximately butmember forces may be computed withsufficient accuracy if the designapproaches the ideal conditions.
The Tallman Road bridge displays two
peculiar details that are contrary to theideal conditions and to subsequentpractice. The most obvious is the hipjoint, which has two pins rather thanone. One pin carries the vertical eyebarand the other carries the diagonal eye-bar pair. Because the longitudinal axesof the inclined end post, top chord,vertical and diagonal members do not
meet at a common point, bending isinduced in the end post and top chord.
The second peculiarity of the TallmanRoad bridge is that each lower chordeyebar spans two deck panels andhas three eyes: one at each end andone in the middle. When gravity load
is applied to a truss, the panel pointsnear midspan typically deflect down-ward more than those near the ends.If the truss conforms to the ideal con-ditions, the members rotate but remainstraight as the panel points deflect.Obviously this behavior cannot beachieved by a three-hole eyebar.Thus, these unusual lower chord eye-bars are subject to bending as well asaxial tension.
Strength Not Predicted byConventional Truss AnalysisConventional analysis predicts that thelower chord of a single-span throughtruss is always in tension when thebridge is carrying gravity load.However, the lower chords in the endpanels of the Charlotte Highwaybridge were observed to be slack (i.e.,subjected to compression rather thantension) when the bridge was in ser-vice in its original location. Thosemembers remained slack after thevehicular railings and deck wereremoved in preparation for moving the
bridge from its masonry abutments.However, when the bridge was freed
from its inoperative expansion bear-ings, that end appeared to moveinland several inches and cracksopened where the wingwalls join theabutments. Apparently the upperchord and end posts had been func-tioning as an arch as well as restrain-ing displacement of the heavyabutments and fill.
Design wind loadshave increasedsignificantly
Table 3. Uniformly distributed design live loads for highway bridge trusses inpounds per square foot (kN/m2).
* Prescribes an impact factor, which is included in the tabulated values # For 16 foot (4.88 m) deck width
Whipple5
ASCE5
Waddell15
Waddell*16
American Bridge Co.*4
Michigan Highway Comm.13
Waddell*#17
Ketchum*12
Illinois Highway Comm.12
Wisconsin Highway Comm.12
AASHTO (pedestrian)#2
1846
1875
1883
1901
1901
1910
1916
1920
1920
1920
1997
100
(4.79)
100-70
(4.79-3.35)
100-80
(4.79-3.83)
170-113
(8.14-5.41)
125-100
(5.99-4.79)
100
(4.79)
161-107
(7.71-5.12)
151-116(7.23-5.55)
125
(5.99)
120
(5.74)
67
(3.21)
100
(4.79)
75-50
(3.59-2.39)
90-80
(4.31-3.83)
149-98
(7.13-4.69)
125-94
(5.99-4.50)
100
(4.79)
144-95
(6.89-4.55)
126-89(6.03-4.26)
100
(4.79)
93
(4.45)
65
(3.11)
100
(4.79)
60-40
(2.87-1.92)
70-60
(3.35-2.87)
120-80
(5.75-3.83)
100-69
(4.79-3.30)
100
(4.79)
119-80
(5.70-3.83)
103-60(4.93-2.87)
85
(4.07)
50
(2.39)
65
(3.11)
Source YearSpan
50 feet 100 feet 200 feet(15.2 m) (30.5 m) (61.0 m)
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14 Welding Innovation Vol. XVIII, No. 3, 2001
Prior to lifting the six-panel BauerRoad bridge from its original abut-ments, the contractor removed railings,decking and stringers. Then a liftingsling was attached to the upper lateralstruts at the third points of the span.Conventional truss analysis predictsthat the bottom chord will be com-pressed when the bridge is lifted in thismanner. Since the bottom chord con-sists of eyebars, which have negligible
resistance to compression, it seemedlikely that the trusses would collapse.The fact that the lift was accomplishedwithout damage attests that the upperchord, hip joints and end posts pos-sess significant bending strength.
Conventional truss analysis mayunderestimate the strength of a metaltruss bridge. More comprehensiveanalysis techniques coupled with
detailed modeling of connections maymake it possible to quantify additionalstrength.
Inadequate Resistanceto Wind LoadBy modern design standards, the
rehabilitated project bridges had inad-equate resistance to wind load. It wasnecessary to employ a provision1 thatpermits design wind speed to beadjusted from a nominal 100 MPH(45 m/s) to reflect favorable localconditions. The inland location of thePark and the low and sheltered sitesof the project bridges justify a designwind velocity of 70 MPH (31 m/s).Despite the resulting 50% reductionof wind force, the original anchorbolts typically were inadequate, and
each of the three bridges manifestedother deficiencies.
Analysis of the 133rd Avenue bridgepredicted that modern design windloads would cause net axial compres-sion of the windward lower chord eye-bars. Since eyebars have negligibleresistance to compression, they wouldbuckle and the truss would becomeunstable. This was corrected byinstalling an unusually heavy deck tocreate enough tension in the lowerchord to counteract the compressioninduced by wind. Alternatively, it mayhave been possible to rely on the deckor upper chord to stabilize the trussesas suggested in the preceding section.
The deck lateral ties of the TwentyMile Road bridge were evaluatedusing the assumed strength of steelproduced before 19053 and found tobe inadequate. The ties, like otherparts of this bridge (Figure 4) were too
badly corroded to be salvaged.Replacing them with new steel, in theoriginal sizes, was sufficient to providethe required wind resistance.
Structural analysis showed that theoriginal portal braces of the Gale Roadbridge were inadequate. Vertical strutshad been arc welded to the latticepanels sometime after construction,apparently to correct perceived weak-
Figure 4. Severely corroded sections of the Twenty Mile Road bridge werereplaced by welding new steel to sound original material.
Figure 5. Forge-welded loop eyebars like these are obsolete.
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Welding Innovation Vol. XVIII, No. 3, 2001 15
ness, and localized bending of hori-zontal members occurred after thesereinforcements were installed. Theoriginal portal braces will be retained
for display but not installed on therehabilitated bridge. The replacementportal braces have larger connectiongussets than the originals, and the lat-tice is steel angles of the same widthas the original flat bars. The configura-tion and overall dimensions of theoriginal portal braces are duplicated.
Features Not Covered in CurrentSpecificationsPony trusses and loop eyebars (Figure5) are obsolete, and there are no cur-rent standards to guide assessment ofthese features. Pony trusses are proneto lateral instability of the top chords.That is, the bridge tends to fold inwardunder heavy load. The two rehabilitat-ed pony trusses were checked for sta-bility by Holts method8 and both werefound to have adequate factors of
safety for pedestrian loading.
Single-load tests of seventeenwrought iron loop eyebars reported by
Ellerby et al6 demonstrated that frac-ture may occur at a forge weld ratherthan in the body of a bar, sometimesat a load significantly less than thedesign strength of the bar. As part ofthe same investigation, twenty-sixwrought iron loop eyebars wererepeatedly loaded to working stress
level. The number of load cycles tofailure suggests that the bars couldhave remained in highway service formany more decades. When fatiguefractures finally did occur, they were inthe loops (except for two bars, whichinitially had large cracks at forgewelds). The investigators speculatedthat repeated flexing of the loops wasa critical factor and noted the deleteri-ous effect of poor fit on the pin.
The usual practice for the project
bridges is to inspect eyebar eyes andforge welds visually and by ultrasonicand dye penetrant methods (Figure 6).Cracks are ground out and bars arebuilt back to original profile by arcwelding. Testing has shown that care-ful arc welding restores full strength6.
Conclusion
Selected historic metal truss bridgesthat are rehabilitated to near-originalcondition can satisfy modern safetystandards for pedestrian service. Thisis demonstrated by the bridges ondisplay in the Calhoun County HistoricBridge Park.
Acknowledgements
Dennis A. Randolph, ManagingDirector, Calhoun County RoadCommission and Board of PublicWorks, developed the concept for
the Historic Bridge Park and providesdirection and support. The projectdirector is Vern Mesler and thehistorian is Elaine Davis.
References
1. AASHTO (1996), Standard Specifications forHighway Bridges, sixteenth edition, Am.Assoc. State Highway and TransportationOfficials.
2. AASHTO (1997), Guide Specifications forDesign of Pedestrian Bridges, Am. Assoc.State Highway and Transportation Officials.
3. AASHTO (2000), Manual for ConditionEvaluation of Bridges 1994, second edition asrevised by the 1995, 1996, 1998 and 2000Interim Revisions, Am. Assoc. State Highwayand Transportation Officials.
4. Burr, C. E., and Falk, M. S. (1905), TheDesign and Construction of Metallic Bridges,John Wiley and Sons, New York.
5. Edwards, L. N. (1959), A Record of Historyand Evolution of Early American Bridges,University Press, Orono, Maine.
6. Ellerby, H. A., Sanders, W. W., Jr., Klaiber, F.W., and Reeves, M. D. (1976), Service Loadand Fatigue Tests on Truss Bridges, J.Structural Division, Am. Soc. Civil Engineers,n. ST 12, Dec., p. 2285-2300.
7. Ferris, H. W., ed. (1990), Iron and SteelBeams 1873 to 1952, tenth printing, Am. Inst.of Steel Construction.
8. Galambos, T. V., ed. (1988), Guide to StabilityDesign Criteria for Metal Structures, fourth edi-tion, John Wiley and Sons, New York.
9. Hyde, C. K. (1993), Historic Highway Bridgesof Michigan, Wayne State University Press,Detroit.
10. IATM (1900), Proposed StandardSpecifications for Structural Steel for Bridgesand Ships, Bulletin 8, May, Proceedings, v. I,Intl. Assn. for Testing Materials - Am. Section,p. 81-86.
11. IATM (1900), Proposed StandardSpecifications for Wrought Iron, Bulletin 17,May, Proceedings, v. I, Intl. Assn. for TestingMaterials - Am. Section, p. 129-134.
12. Ketchum, M. S. (1920), The Design ofHighway Bridges of Steel, Timber andConcrete, second edition rewritten, McGraw-Hill Book Co., New York.
13. Michigan, State of (1910), GeneralSpecifications for Highway Bridges, ThirdBiennial Report of the State HighwayCommission, Wynkoop Hollenbeck CrawfordCo., Lansing, Mich.
14. NPS (1992), The Secretary of the InteriorsStandards for the Treatment of HistoricProperties, U. S. Department of the Interior,National Park Service, PreservationAssistance Division, Washington.
15. Waddell, J. A. L. (1883), General Suggestions
as to the Conditions Proper to be Required inOrdinary Iron Highway Bridge Construction,Transactions, Am. Soc. Civil Engineers, v. 12,p. 459-478.
16. Waddell, J. A. L. (1901), De Pontibus: aPocket-Book for Bridge Engineers, first editionsecond thousand, John Wiley and Sons, NewYork.
17. Waddell, J. A. L. (1916), Bridge Engineering,first edition second thousand, John Wiley andSons, New York.
Conventional truss analysismay underestimate
the strength of a bridge
Figure 6. Dye penetrant inspection of
a forge weld.
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16 Welding Innovation Vol. XVIII, No. 3, 2001
Many readers of this publicationregard welding as an artfor thewelders at Mt. Vernon Machine & Tool,that is literally true. The precision met-alworking firm located in Mt. Vernon,Ohio, provides the essential weldingand cutting services needed to realizethe artistic vision of sculptor BarryGunderson, Professor of Art at KenyonCollege in Gambier, Ohio.
According to president Gail Stenger,working with Gunderson is a welcomechange of pace for his companys fivefull-time welders. We rotate the workso that all of the welders have achance to work on Barrys pieces. Hebrings a breath of fresh air into ourweld shop.
A Collaborative Effort
The relationship began a little morethan a decade ago, when Gundersonssculpture students started to frequentthe metalworking shop looking to pur-chase round bar and pieces of flatsteel for their studio projects. We real-ly got to know Barry through his stu-dents, Stenger recalls. To date, Mt.Vernon Machine & Tool has fabricatedfive of Gundersons sculptures, four inaluminum and one in stainless steel.
The collaborative effort begins after
Gunderson is notified that he is a final-ist in the competition for a commis-sion. At that point, Stenger says, hecontacts me. He brings in a smallmodel of the piece so we can discusshis ideas for it, and talk about how hewould like to see it fabricated. I do acost breakdown so he can submit abudget.
The working relationship is now sowell-established that Gunderson hashis own key to the Mt. Vernon weldshop. He sometimes spends eveningsthere, grinding or painting sections ofthe current project. As we get closerto the end of a commission, hes prettymuch here all the time, Stengernotes, grinding so he can get exactlythe texture he wants. Gunderson
also does much of the plasma cuttingwork on his sculptures.
Understorms
The first piece Stengers companywelded for Gunderson wasUnderstorms, which represented thesculptors first commission from theOhio Arts Council Percent for ArtProgram, a statewide initiative thatplaces public art in state facilities. Thiswork, like the other aluminum sculp-tures created at his shop, was weldedusing gas metal arc, spool-style, withassist guns on the welders, accordingto Stenger, who added that GTAW iscommonly used on the smaller parts.Mt. Vernon Machine & Tool installedthe sculpture, with Gundersons over-sight, at Franklin Park Conservatory inColumbus, Ohio, in 1991.
Spountain
Several years later, Gunderson was afinalist for another Ohio Percent for Artcommission. This time, he approachedStenger with a 2 ft. (0.6 m) cardboardmodel for another piece he proposedfabricating out of aluminum, this onecalled Spountain. The 30-ft. (9 m) tallsculpture would be, said Gunderson,an abstraction of water. Due to thesize of the piece and in consideration
of wind shears, Stenger advised that itbe constructed not of aluminum, but ofstainless steel. The advice duly taken,Mt. Vernon Machine & Tool proceededto fabricate the piece, using SMAW tocreate the structure, and GMAW to fin-ish the skin surface.
Spountain was too tall to fit insidethe Mt. Vernon shop, so a cement pad
was built outside to accommodate itduring fabrication. The final product,weighing almost 10,000 lbs. (4,500kg), took 15 months to create, fromconception to installation. Spountainnow resides in front of the George V.Voinovich Livestock and Trade Centeron the Ohio State Fairgrounds inColumbus.
Coventry Arch
Gundersons most recent collaborationwith Mt. Vernon Machine & Tool result-ed in a work that serves as the sym-bolic gateway to a neighborhood (seeback cover). The Coventry PEACEPublic Art Committee, a communitygroup in Cleveland Heights, Ohio,wanted to enhance a newly land-scaped park area in front of a localbranch of the Cleveland Heights-University Heights Public Library.
Ten regional artists responded to a call
for entries; of these, Gunderson wasamong the three finalists. In his propos-al, he explained: I have been fascinat-ed with the complex invention of turningindustrial materialspipes and struc-turesinto anatomical forms Myintent here is to use 12 in. (300 mm)diameter aluminum pipe rolled into a180arch to form a passage way ofgreetingtwo abstract figurative forms
Artistic PrecisionBy Carla Rautenberg
Welding InnovationContributing WriterJames F. Lincoln Arc Welding FoundationCleveland, Ohio.
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on either side four figures, two oneach side, will thus form two arches,one slightly higher than the other My hope is that this figurative clusterwill serve as a symbol of the commu-nitys interactions with each other andwith visitors
Describing the Coventry Arch, Stenger
reported, If Barry had a favorite pro-ject of the ones weve done together,that was it. He explained thatGunderson conducted art workshopswith the children attending nearbyCoventry Elementary School, and thatthe childrens involvement and interestadded an extra dimension to the pro-
ject for all concerned.
The collaboration between artist andwelding shop is one of mutual commit-ment and respect. Barry knows wellgo the extra mile to give him what heneeds. Weve cut the parts apart andrewelded them when he wanted usto, says Stenger. For his part,Gunderson states, I feel very fortu-nate to have such a special relation-ship with Gail and his workers. It trulyhelps me see my artistic visions cometo life.
Mt. Vernon Machine & Tool, in busi-ness since 1924, employs a total of
thirty people. Gail Stenger representsthe fourth generation of his family inthe business. Spountain
Understorms
L
L
L
L
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NON-PROFIT ORG.
U.S. POSTAGE
PAID
JAMES F. LINCOLN
ARC WELDING FND.
This welded aluminum arch provides a visual gateway to a neighborhood. Story on page 16.
P.O. Box 17188Cleveland, OH 44117-1199
The
James F. Lincoln
Arc Welding
Foundation
