Example: biology

Ensuring Weld Quality in Structural Applications

EnsuringWeld Qualityin StructuralApplicationsBy Duane K. Miller, , James F. Lincoln Arc Welding FoundationThe serviceability of a product or structure utilizing the type of information presentedherein is, and must be, the sole responsibility of the builder/user. Many variablesbeyond the control of The James F. Lincoln Arc Welding Foundation or The LincolnElectric Company affect the results obtained in applying this type of variables include, but are not limited to, welding procedure, plate chemistryand temperature, weldment design, fabrication methods, and service guide makes extensive reference to the AWS Structural Welding Code-Steel,but it is not intended to be a comprehensive review of all code requirements, nor is itintended to be a substitution for the code. Users of this guide are encouraged toobtain a copy of the latest edition of the code from the American Welding Society,550 LeJeune Road, Miami, Florida 33126.

Ensuring Weld Quality in Structural Applications, Part I of III By Duane K. Miller, Sc.D., P.E. Manager, Engineering Services The Lincoln Electric Company

Tags:

  Applications, Quality, Ensuring, Structural, Weld, Ensuring weld quality in structural applications

Information

Domain:

Source:

Link to this page:

Please notify us if you found a problem with this document:

Other abuse

Transcription of Ensuring Weld Quality in Structural Applications

1 EnsuringWeld Qualityin StructuralApplicationsBy Duane K. Miller, , James F. Lincoln Arc Welding FoundationThe serviceability of a product or structure utilizing the type of information presentedherein is, and must be, the sole responsibility of the builder/user. Many variablesbeyond the control of The James F. Lincoln Arc Welding Foundation or The LincolnElectric Company affect the results obtained in applying this type of variables include, but are not limited to, welding procedure, plate chemistryand temperature, weldment design, fabrication methods, and service guide makes extensive reference to the AWS Structural Welding Code-Steel,but it is not intended to be a comprehensive review of all code requirements, nor is itintended to be a substitution for the code. Users of this guide are encouraged toobtain a copy of the latest edition of the code from the American Welding Society,550 LeJeune Road, Miami, Florida 33126.

2 (800) information has been provided byThe James F. Lincoln Arc Welding Foundationto assist the general welding weld Quality in Structural Applications , Part I of IIIBy Duane K. Miller, , , Engineering ServicesThe Lincoln Electric CompanyCleveland, OhioThe Roles of Engineers, Fabricators & InspectorsIntroductionIn a mature industry such as weldedsteel construction, it is reasonable tobelieve that the role of the various indi-viduals involved with a given projectwill be well understood and welldefined. Unfortunately, experienceindicates that there is a great deal ofconfusion in this area. Perhaps this isa reflection of misperceptions aboutthe technology itself. Too many other-wise knowledgeable people still regardwelding as a black art, rather than ascience that can be understood andcontrolled. The level of understandingamong many Engineers regarding thisimportant construction process is limit-ed. Regardless of the reason,Engineers frequently do not performtheir professional responsibilities asthey relate to welding.

3 Too often, theydelegate this authority to Inspectors frequentlyoverstep their role, making judgmentcalls that should be the purview of theEngineer. Furthermore, Fabricators donot always take full advantage ofcode-provided latitude for the resolu-tion of many problems. In the end,Owners often pay too much for struc-tures that have been plagued bydelays, unnecessary repairs, andextraneous activities that add little orno value to the problems result when the properroles of the various individuals on theproject are not understood. The mostserious infractions occur when peopleaccept responsibility for areas in whichthey have no authority or qualifica-tions. This can result in disaster, butfortunately such cases are rare. Morefrequently, key individuals fail to carryout all of their appropriate responsibili-ties, causing costly the design-build approach com-monly used in Europe, communicationis enhanced because one organizationhas financial responsibility for theentire project.

4 In the , however,the common practice that separatesthe design phase from the construc-tion phase requires a clear under-standing of the responsibilities of thevarious parties. The roles are definedin codes, specifications, and contractdocuments. The AWS Welding Code - Steel,defines such roles as they relate towelded construction. In addition torestating sections of the code itself,this paper will outline a philosophy thatis conducive to increased cooperationand communication, and will foster thecreation of higher Quality productswhile minimizing fabrication three-part series on Ensuring weld Quality in Structural Applications covers the following:Part I reexamines the roles of the Engineer, the Fabricator, and theInspector, as they relate to welded construction. The proper roles aredefined, and misunderstandings corrected. First published inWelding Innovation, Vol. XIII, #2, II emphasizes the importance of effective visual inspection and itsvital role in achieving weld Quality .

5 First published in Welding Innovation,Vol. XIII, #3, III discusses alternate acceptance criteria and explains the Engineer sresponsibility for invoking such criteria. First published in WeldingInnovation, Vol. XIV, #1, the series, references have been updated to cite specific sections of the AWS Structural Welding Code - problems resultwhen the proper rolesof the various individuals on the project are not InnovationThe James F. Lincoln Arc Welding FoundationVarious Roles DefinedAt the heart of the issue is the properdefinition of the roles and the responsi-bilities of various individuals involved inwelded fabrication. The following aretaken from the AISC Code of StandardPractice and/or the AWS D1. 1-98 Structural Welding Code - Steel:Owner:The owner of the proposed structureOR that individual s designated repre-sentatives, who may be the Architect,Engineer, General Contractor, PublicAuthority, or :The Owner s designated representa-tive with the full responsibility for thedesign and integrity of the Contractor:The Owner s designated representa-tive with the full responsibility for theconstruction of the :The party responsible for furnishingfabricated Structural :The party responsible for the erectionof the Structural Inspector:The duly designated person who actsfor, and on behalf of, the Owner or theEngineer in all inspection and qualitymatters within the scope of the con-tract documents.

6 (In some codes, suchas BridgeWelding Code, this Inspector is knownas the Inspector, that is, theQuality Assurance Inspector.)Fabrication/Erection Inspector:The duly designated person who actsfor, and on behalf of, the Contractor inall inspection and Quality matters with-in the scope of the contract docu-ments. (In , this Inspector isknown as the Inspector, that is,the Quality Control Inspector.)Inspector:When the term Inspector is used with-out further qualification, it appliesequally to both the Verification andFabrication/Erection the purposes of this paper, com-ments directed toward the Fabricatorapply equally to the Erector. Sincemost or all of the welding will be per-formed by either the Fabricator orErector, the General Contractor willnot be considered in this term Engineer will be used in lieuof Engineer has the ultimate and fullresponsibility for the integrity of thestructure. It is the Engineer who mustestablish the required Quality level forall welded fabrications.

7 This may bedone by invoking a standard such asthe Code. It is imperative thatthe Engineer understand the require-ments, restrictions, and implications ofthe full code. The Engineer is respon-sible to ensure that the code provi-sions are adequate for the provisions may be requiredfor unique structures, and theserequirements must be invoked in contract documents. The Engineer isresponsible for determining and speci-fying the level of Quality required. TheEngineer is also responsible to ensurethat the specified level of Quality isdelivered by the Fabricator. TheEngineer has a professional responsi-bility to the Owner to deliver the project in a timely fashion, and at an appropriate assist in the Quality issues, theEngineer may employ the services ofa Verification Inspector. Under ,this is left up to the Engineer s discre-tion. A Verification Inspector may beengaged either to duplicate the ser-vices of the Fabrication Inspector, or to supply spot checks.

8 However, theEngineer may choose to rely solelyupon the Fabrication Inspector toensure the necessary Quality isachieved. Many factors enter into thisdecision, including: the complexity of the structure; the degree of redundancy involved;and the relative level of confidence theEngineer has in the Fabricator is responsible for deliv-ering a Quality product to the the Engineer must be responsi-ble to ensure the level of Quality isachieved, it is ultimately theFabricator s responsibility to produce aquality product. To this end, theFabricator will employ FabricationInspectors ( Inspectors) to monitorthe welding operations and inspect theEffective visual inspection requires that the Inspector be present when weldingis being InnovationThe James F. Lincoln Arc Welding Foundationfinal product. Under a shop qualifica-tion program, it is required that theinspection functions be kept organiza-tionally separate from the manufactur-ing operations, in order to give Inspectors the necessary authori-ty to carry out their is important to understand that sincethe Fabricator does all the welding,only the Fabricator can produce quali-ty welds.

9 Inspectors cannot improve the Quality of the product that hasbeen produced. The Inspector simplymeasures the level of Quality achieved,and accepts those products that arewithin are responsible to ascertainthat all fabrication and erection bywelding is performed in accordancewith the requirements of the contractdocuments. When contract docu-ments invoke certain specifications orcodes, the Inspector must ensure thatall such requirements are met. It isimportant to note that the emphasis isplaced on acceptance and compli-ance to the specification. A prevail-ing but mistaken impression ofInspectors is that their primary respon-sibility is to rejectout-of-compliancework. This is more than an issue ofsemantics. The ability to reject a par-ticular weldment is ultimately theEngineer s responsibility. TheInspector s responsibility is to acceptmaterials that are in this approach may seem new orrevolutionary to some people, theauthor believes that it is the primaryphilosophy presented in codes.

10 And,to eliminate any dispute or potentialmisrepresentation of code intentions, itis the author s opinion that this shouldbe the philosophy of the code evenwhen it is not, because it will result inoptimum value to the DueTo Choice of WordsThe belief that the primary function ofInspectors is acceptance of productsthat are within established criteria isgenerally supported by the Code,although deviation from this generalphilosophy is sometimes expressed inthe code. In the author s opinion, thisis more a reflection of poor wording onthe part of the code writers than a rep-resentation of overall philosophy. Theexamples that conflict with the generaltrend will be cited, and proposedrefinements following references with appropri-ately highlighted portions support thecontention presented above: Fabrication/erection .. inspectionand tests shall be performed .. toensure that materials and workman-ship meet the requirementsof thecontract documents ( ).


Related search queries