Extending Bridge Service Life Through Field Welded Repairs and Retrofits (2016)

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44 Adapted from AWS A3.0 (AWS 2010). Arc strike—A discontinuity resulting from an arc consisting of any localized remelted metal, heat-affected metal, or change in surface profile of any metal object. Back gouging—Removal of weld metal and base metal from the weld root side of a welded joint to facilitate complete fusion and complete joint penetration upon subsequent welding from that side. Backing—A material or device placed against the back side of the joint to support and retain molten metal. A material or device placed against the back or the side of the joint adja- cent to the joint root or at both sides of a joint in electroslag and electrogas welding, to support and shield molten weld metal. Material may be partially fused or remain unfused during welding and may be either metal or nonmetal. Base material (metal)—Material to be welded. Base metal—Metal or alloy that is welded, brazed, soldered, or cut. Carbon equivalent (CE)—An empirical value in weight percent, relating the combined effects of different alloying elements used in the making of carbon steels to an equiva- lent amount of carbon. This value can be calculated using a mathematical equation. Certified Weld Inspector (CWI)—An AWS-certified weld inspector performs visual inspections on welded steel pieces to be used in the construction of bridges and other structures. They must be able to detect possible welding defects, use test and measuring instruments, and monitor any repairs to faulty welds. CJP (complete joint penetration) groove weld—A joint root condition in a groove weld in which weld metal extends through the joint thickness. A groove weld that has been made from both sides or from one side on a backing having complete penetration and fusion of weld and base metal throughout the depth of the joint. Crack—A fracture type discontinuity characterized by a sharp tip and high ratio of length and width to opening displacement. Engineer—A duly designated individual who acts for and/or in behalf of the owner on all matters within the scope of the work. Fatigue—Weakening or breakdown of a material as a result of repeated cycles of stress. Field welding—Welding that occurs outside of a fabrication shop. Welds made at a location other than the shop or the place of initial construction. Fracture critical member—Steel tension members or steel tension components of members whose failure would be expected to result in the partial or full collapse of the bridge. Heat affected zone (HAZ)—Portion of the base metal where the mechanical properties or microstructure have been altered by the heat of welding, brazing, soldering, or thermal cutting. Inspection—Examination by the Owner or the Fabricator of processes and products to verify conformance with contract requirements. Mill Test Report (MTR)—A quality assurance document used to certify a material’s chemical and physical properties and that states the material’s compliance with an international standards organization specific standard. Nondestructive examination (NDE)—The act of determin- ing the suitability of some material or component for its intended purpose using techniques that do not affect its serviceability. Nondestructive testing (NDT)—Analysis techniques used to establish the properties of a material or identify defects in a material or member without causing damage to the material or member. Partial joint penetration (PJP)—A joint root condition in a groove weld where weld metal extends partially through the joint thickness. Joint penetration that is intentionally less than complete. A portion of the joint is not fused. Porosity—Cavity-type discontinuities formed by gas entrap- ment during solidification or in a thermal spray deposit. Preheating—Application of heat to the base metal immedi- ately before welding brazing, soldering, thermal spraying, or cutting. The heat applied to the base metal or substrate to attain and maintain preheat temperature. Procedure Qualification Record (welding)—A document providing the actual welding variables used to produce an acceptable test weld and the results of tests conducted on the weld to qualify a Weld Procedure Specification. Quality assurance (QA)—Quality assurance encompasses the activities undertaken by the Owner to verify that the final product satisfies contract requirements, including verifying that quality control is performed effectively. Quality control (QC)—Activities undertaken by the Con- tractor or Fabricator to ensure a product is provided that meets contract requirements. Residual stress—Stress present in a joint member or material that is free of external forces or thermal gradients. Undercut—A groove melted into the base metal adjacent to the weld toe or weld root and left unfilled by weld metal. Weld Procedure Specification (WPS)—The demonstration that welds made by a specific procedure can meet prescribed standards. A document providing the required welding variables for a specific application to ensure repeatability by properly trained welders and welding operators. Weldability—Capacity of a material to be welded under the fabrication conditions imposed into a specific, suit- ably designed structure and to perform satisfactorily in the intended service. Welder—One who performs a manual or semiautomatic welding operation. GLOSSARY

45 Welder certification—Written certification that a welder has produced welds meeting a prescribed standard of welder performance. Welder performance qualification—The demonstration of a welder’s ability to produce welds meeting prescribed specified standards. Welding—A joining process that produces coalescence of materials by heating them to the welding temperature, with or without the application of pressure or by the appli- cation of pressure alone, and with or without the use of filler metal. Welding electrode—A component of the welding circuit through which current is conducted and that terminates at the arc, molten conductive slag, or base metal. Welding symbol—A graphical representation of the specifi- cations for producing a welded joint.