448Structural Field Welding

4.1 Procedure Qualification . Use the proper classification and size of electrode, arc length, voltage, and

amperage for the thickness of the material, type of groove, welding positions, and other circumstances of the work. Submit WPSs for FCAW, qualified in accordance with AASHTO/AWS D1.5 for approval before any field welding on a project.

4.2 Welder Qualification . Provide Department certification papers for each welder and for each welding process

to be used before welding, except for miscellaneous welds described in Section 448.4.2.1.1., “Miscellaneous Welding Applications.” The Department issues certification as described in Section 448.4.2.2., “Certified Steel Structures Welder.”

4.2.1 Miscellaneous Welding . A qualified welder is an experienced welder who is capable of making welds of

sound quality but does not have Department certification papers. The Engineer will check the welder’s ability by conducting a jobsite test in accordance with Section 448.4.2.1.2., “Miscellaneous Weld Qualification Test,” before welding begins. Furnish all materials and equipment necessary for this test. 4.2.1.1. Miscellaneous Welding Applications . A welder certified for structural or reinforcing steel or a qualified welder may make miscellaneous welds of the following types:  splicing reinforcing steel to extend bars in the bottom of a drilled shaft;  attaching chairs to the reinforcing steel cage of a drilled shaft;  armor joints and their supports;  screed rail and form hanger supports where permitted on steel units;  reinforcing steel to R -bars for lateral stability between prestressed beams, spirals, or bands to reinforcing bars in drilled shaft cages;  permanent metal deck forms;  additional steel added in railing when slip-form construction is used; and  other similar miscellaneous members that have no load-ca rrying capacity in the completed structure. 4.2.1.2. Miscellaneous Weld Qualification Test. A qualified welder must pass a jobsite Miscellaneous Weld Qualification Test before welding.  Make a single- pass fillet weld of 1/4- in. maximum size in the vertical position approximately 2 in. long on 1/2-in. plate in the location shown in Figure 1. Use the same electrode proposed for the work.  The Engineer will visually inspect the fillet weld for a reasonably uniform appearance and then rupture the weld as shown in Figure 2 using force or by striking it with a hammer.  The fractured surface of the weld will be inspected to ensure complete penetration into the root of the joint, complete fusion to the base metal, and no inclusion or porosity larger than 3/32 in. in its greates t dimension. Figure 1 Miscellaneous Qualification —Fillet Weld Break Specimen Figure 2 Miscellaneous Qualification —Method of R upturing Specimen A welder who fails the Miscellaneous Weld Qualification Test may retest under the following conditions .  The retest occurs immediately and consists of two test welds as described above, with both test specimens meeting all the requirements.  The retest occurs after 30 days if the welder provides evidence of further training or practice. In this case , the test consists of a single test weld. Qualification by the Miscellaneous Weld Qualification Test is effective immediately upon satisfactory completion of the test and remains in effect for the duration of a project.

4.2.2 Certified Steel Structures Welder . Before making non- miscellaneous welds on structural steel, a welder

must pass the AASHTO/AWS D1.5 qualification test for groove welds for plates of unlimited thickness in the vertical (3G) and overhead (4G) positions with the following additional requirements . 682  Use metal for test plates that meets Item 442, “Metal for Structures,” with a minimum yield point of 36 ksi. The minimum width of test plate must be sufficient to accommodate the radiograph inspection of 5-1/4 continuous inches of the weld, not counting the ends of the weld.  Use approved electrodes meeting the required class in accordance with Table 1 and, in the case of FCAW, in conformance with the approved WPS.  Have a radiographic inspection performed on the weld on each test plate. Any porosi ty or fusion- type discontinuity with greatest dimension larger than 1/16 in. found in the weld will result in failure of the test. Discontinuities with greatest dimension less than 1/16 in. are acceptable provided the sum of their greatest dimensions does not exceed 3/8 in. in any inch of weld.  Have two side-bend specimens prepared, tested, and inspected for each test plate. The test must be administered by an approved laboratory and welding observed by laboratory personnel. Submit two copies of the certifi cation issued by the laboratory, all accompanying test papers, and the radiographic films to the Bridge Division for review. The Bridge Division issues Department certification papers if the laboratory’s certification is approved. A welder must also demons trate to the Engineer a thorough knowledge of the required welding procedures together with the ability and desire to follow them and make welds of sound quality and good appearance. The certification issued by an approved laboratory is accepted for 1 mo. from the time of certification, during which time the welder may work on Department projects if the work is satisfactory. Certification papers issued by the Department remain in effect as long as the welder performs acceptable work as determined by the Bri dge Division. The certification may be cancelled at any time if the welder’s work is not acceptable. For SMAW, a welder certified using EXX18 electrodes is qualified to weld with all approved SMAW electrodes up to E90XX to join metals with a maximum specif ied yield strength of 65 ksi.

4.3 Welding Steel Structures.

4.3.1 Electrode Condition.

4.3.1.1. SMAW . For electrodes with low -hydrogen coverings in conformance with AWS A5.1, dry to the manufacturer’s written drying instructions or dry for at least 2 hr. between 450°F and 500°F. For electrodes with low -hydrogen coverings conforming to AWS A5.5, dry for at least 1 hr. between 700°F and 800°F or as specified by the electrode manufacturer. If using electrodes from a newly opened, undamaged, hermetically sealed container, drying is not required. Store electrodes in ovens held at a temperature of at least 250°F immediately after drying or removal from hermetically sealed container. Elapsed time permitted between removal of an electrode from the storage oven or hermetically sealed c ontainer and use of the electrode is shown in Table 2. If the electrodes have the moisture resistance designator “R” and are being used on steel with minimum specified yield strength of 50 ksi or less, exposure time may be increased up to 9 hr. Table 2 SMAW Electrode Exposure Limits Electrode Type Exposure Time (hr.) E70 4 E80 2 E90 1 Leave electrodes in the holding oven for at least 4 hr. at 250°F before reusing if they are placed back in it before the times shown in Table 2 have lapsed. The Engineer may reduce times allowed for use without re- drying in humid atmospheres. Do not redry electrodes more than once. Do not use electrodes with f lux that has been wet, cracked, or otherwise damaged. 4.3.1.2. FCAW . Protect or store welding wire coils removed from the original package to keep their characteristics or welding properties intact. Do not use coils or portions of coils that are rusty. 683 4.3.1.3. Special Appl ications . Dry electrodes for fracture- critical applications or when welding steel not shown in Table 1 in conformance with the manufacturer’s specifications and in accordance with AASHTO/AWS D1.5.

4.3.2 Environmental Conditions . Do not weld when the air temperat ure is lower than 20°F; when surfaces are

wet or exposed to rain, snow, or wind; or when operators are exposed to inclement conditions. Provide wind breaks to protect welding operations from winds greater than 5 mph.

4.3.3 Assembly and Fitup . Verify that ends of members to be welded are prepared in conformance with the

welded joint detail specified. Refer to Figures 3, 4, and 5 for proper end preparation and weld details of girder splices. Bring the parts to be joined by fillet welds into as close contact as poss ible, not separated more than 3/16 in. Increase the leg of the fillet weld by the amount of the separation if the separation is 1/16 in. or more. Keep the separation between faying surfaces of lap joints and of butt joints landing on backing strips to no m ore than 1/16 in. Make suitable allowance for shrinkage, and never restrain the joint on both sides in any welding process. Use the following fitup procedure for groove welds for butt joints .  Align splices of beams and girders joined by groove welds with t he center of gravity of both cross- sections coinciding or each flange vertically offset equally. Fit beams and girders with offset webs with the webs aligned and the flanges offset laterally. Make the joint with a smooth transition between offset surfaces and with a slope of no more than 1:4 when flanges are offset or abutting parts differ in thickness or width by more than 1/8 in.  Space members to provide a 3/16- in. root opening at the nearest point. At other points of the joint when the spacing provides up to a 7/16 -in. opening, correction may be made by buildup up to 1/8 in. on each bevel nose. Rebevel openings exceeding 7/16 in. and move the parts to be joined closer together to bring the joint within the maximum buildup limits. Allow buildups to cool to the maximum preheat and interpass temperatures before welding the joint.  Bring all members into correct alignment and hold them in position using acceptable clamps while welding. Complete all butt splices before welding diaphragms or sway bracing in a particular section of a unit. Diaphragms and sway bracing may be welded in a unit behind the splice welding to provide stability , except where such welding interferes with butt splice adjustments, such as at a drop- in segment of a continuous unit. Complete all splices before welding beams or girders to shoes. Figure 3 Girder Splice Details Figure 4 Girder S plice Details ( Flange) Figure 5 Girder Splice Details (Web) 685 4.3.4. Preheat . Preheat ahead of welding both groove and fillet welds (including tack welding) to the temperatures shown in Table 3. Keep preheat and interpass temperatures high enough to prevent cracks. The preheat temperatures shown in Table 3 are minimums, and higher preheats may be necessary in highly restrained welds. Preheat the base metal when it is below the required temperature so that parts being welded are not cooler than the specified temperature within 3 in. of the point of welding. Measure preheat temperature on the side opposite to which the heat is applied at points approximately 3 in. away from the joint. Completely weld a joint before allowing it to cool below the specified temperature. Always deposit enough weld to prevent cracking before allowing a joi nt to cool. Do not allow preheat and interpass temperatures to exceed 400°F for thickness up to 1- 1/2 in. and 450°F for greater thicknesses. Table 3 Minimum Preheat and Interpass Temperature for Welding with Low -Hydrogen Electrodes Thickest Part at Point of Welding Temperature Up to 3/4 in., inclusive 50°F More than 3/4 in. up to 1 -1/2 in., inclusive 70°F More than 1 -1/2 in. up to 2 -1/2 in., inclusive 150°F More than 2 -1/2 in. 225°F Preheat the material in accordance with Table 4 when E7010 or E8010 electrodes are used for tacking or temporary root pass. Table 4 Minimum Preheat Temperature for Welding with E7010 or E8010 Electrodes Thickest Part at Point of Welding Temperature 1/2 in. and less 150°F 9/16 in. through 3/4 in. 200°F 13/16 in. through 1 -1/2 in. 300°F More than 1 -1/2 in. 400°F Use preheat and interpass temperatures for the thicker plate thickness when joining steels of different thickness. Preheat base metal to at least 70°F when the base metal temperature is below 32°F and maintain this minimum temperature during welding. Preheat base metal to 200°F before starting to weld if it is moist. Preheat fracture- critical applications in accordance with AASHTO/AWS D1.5.

4.3.5 Welding Practice. Use an approved procedure to control shrinkage and distortion. Weld FCAW in

conformance with an approved WPS. Weld as required by the Contract or erection drawings. Do not change the location or size of welds without approval. Do not make temporary welds for transportation, erection, or other purposes on main members , except as shown on the plans or approved. Use a crayon, paint , or other approved method to mark each groove weld to identify the welder who performed the work. Use the stringer -bead technique where possible for groove welds. Progress upward in vertical welding passes using a back -step sequence, keeping the end of the low -hydrogen electrode contained within the molten metal and shield of flux unless the electrode manufacturer’s specifications indicate otherwise. Begin and terminate groove welds at the ends of a joint on extension bars. Make edge preparation and thickn ess of extension bars the same as that of the member being welded but extending at least 2 in. beyond the joint. Remove extension bars using a cutting torch or arc -air gouging and grind the flange edges smooth after the weld is completed and cooled. Clean any defects exposed by the grinding, fill them with weld metal, and regrind them to a uniform finish. Grind so that grind marks are parallel to the flange and avoid excess grinding of the parent metal. Clean and fuse tack welds thoroughly with the final weld. Remove defective, cracked, or broken tack welds. 686 Gouge, chip, or otherwise remove the root of the initial weld to sound metal for all groove welds, except those produced with the aid of backing or those on steel piling or armor joints, before welding is started on the second side. Clean the back side thoroughly before placing the backup pass. Fuse the weld metal thoroughly with the backing, and use backing that is continuous for the full length of the weld. Make a continuous length of backing by welding shorter sections together only under the following conditions .  All splices in the backing are complete joint penetration (CJP) groove welds made with the same controls as similar CJP groove welds in the structure.  The welds are radiographed and examined as described in Section 448.4.3.7., “Radiographic Inspection,” to ensure weld soundness.  All welding and testing of the backing are complete before the backing is used to make the structural weld. 4.3.5.1. High -Cellulose Electrodes for Root Passes. E7010 and E8010 electrodes may be used when welding the root passes of beam and girder splices if the work is preheated in accordance with Table 4. Remove the E7010 or E8010 electrode pass completely by arc -air gouging and replace it using a low -hydrogen electrode after the root passes are backed up. 4.3.5.2. Welding Sequence . Make beam and girder splices using the sequences shown in Figure 6. (Some members will require fewer or more passes than Figure 6 shows.) Alternate welds from flat to overhead to prevent heat buildup along bevel edge. Arrange the passes between the top and bottom flange to maintain balance and symmetry . Place passes 1, 2, and 3 in the top flange, followed by passes 4, 5, and 6 in the bottom flange (Figure 6) for rolled I -beams and built -up girders. Gouge out and replace passes 1 and 4, which always are placed in the overhead position. Next, place passes 7, 8, and 9 in the top flange, followed by passes 10, 11, and 12 in the bottom flange. Continue with placing passes 13–17 in the top flange, followed by passes 18–22 in the bottom flange. Continue to alternate welding between top and bottom flange with at most five passes per flange until the flange splices are complete. Tack weld web after aligning girder webs with short tacks as required to obtain proper alignment. Place pass 23 and pass 24 on the web. Gouge out and replace pass 23. Finish web splice with pass 25. Remove all slag for each lay er, bead, and the crater area, and clean the weld and adjacent base metal before welding over previously deposited metal. Avoid arc strikes, and if they occur, grind resulting cracks and blemishes out to a smooth contour, checking them visually to ensure soundness . Figure 6 Welding Sequence f or Splices f or Material up to 50,000- psi Yield Strength 687 Deviation from the above sequence of weld passes requires approval. Obtain approval from the Bridge Division for welding procedures and sequences for special connections. 4.3.5.3. Electrode Size and Weld Layer Thickness. 4.3.5.3.1. SMAW . 4.3.5.3.1.1. Electrode Size. Use electrodes with the following maximum size:  1/4 in. for all welds made in the flat position except root passes,  1/4 in. for horizontal fillet welds,  1/4 in. for root passes of f illet welds made in the flat position and of groove welds made in the flat position with backing and with a root opening of 1/4 in. or more,  5/32 in. for welds made with low -hydrogen electrodes in the vertical and overhead positions, and  3/16 in. for all other welds. 4.3.5.3.1.2. Weld Size and Layer Thickness . Make the root pass large enough to prevent cracking. Make layers subsequent to the root pass in fillet welds and all layers in groove welds of the following maximum thickness:  1/4 in. for root passes of groove wel ds,  1/8 in. for subsequent layers of welds made in the flat position, and  3/16 in. for subsequent layers of welds made in the vertical, overhead, and horizontal positions. Make fillet weld passes using no larger than:  3/8 in. in the flat position,  5/16 in. in the horizontal or overhead positions, and  1/2 in. in the vertical position. 4.3.5.3.2. FCAW . 4.3.5.3.2.1. Electrode Size. Use electrodes with the following maximum size:  5/32 in. for the flat and horizontal positions,  3/32 in. for the vertical position, and  5/64 in. for the overhead position. 4.3.5.3.2.2. Weld Size and Layer Thickness . Make weld layers, except root and surface layers, no thicker than 1/4 in. Use a multiple -pass split -layer technique when the root opening of a groove weld is 1/2 in. or wider. Use the split-layer techni que to make all multiple- pass welds when the width of the layer exceeds 5/8 in. Ensure each pass has complete fusion with adjacent base metal and weld metal and that there is no overlap, excessive porosity, or undercutting. Do not use FCAW with external gas shielding in a draft or wind. Furnish an approved shelter of material and shape to reduce wind velocity near the welding to a maximum of 5 mph. Make fillet weld passes using no larger than:  1/2 in. in the flat position,  3/8 in. in the horizontal or overhead positions, and  5/16 in. in the vertical position.

4.3.6 Weld Quality . Provide welds that are sound throughout , with no cracks in the weld metal or weld pass.

Completely fuse the weld metal and the base metal and each subsequent pass. Keep welds free of overlap and keep the base metal free of undercut more than 1/100 in. deep when the direction of undercut is trans verse to the primary stress in the part that is undercut. Fill all craters to the full cross -section of the welds. 688 4.3.7. Radiographic Inspection. Conduct radiographic testing (RT) as required in the field, at the expense of the Contractor , by an agency or indivi dual registered and licensed to perform industrial radiography. Follow all applicable rules and regulations for radiographic operations. Testing includes furnishing all materials, equipment, tools, labor, and incidentals necessary to perform the required t esting. The Department may require further tests in accordance with Article 5.10., “Inspection, ” and may perform additional testing, including other methods of inspection. Perform RT in accordance with AASHTO/AWS D1.5. The Engineer will examine and interpr et the resulting radiographs in accordance with AASHTO/AWS D1.5. All radiographs become the property of the Department and remain with the Engineer. Radiographically inspect the full flange width of all flange splices and the top and bottom 1/6 of the web at each splice for field welds of splices in beams or girders. Radiographically retest repaired welds. Make necessary repairs before any further work is done. Additional RT required because of unacceptable welding or poor radiograph quality is at the Contr actor’s expense. RT of particular welds shown on the plans is in addition to the RT required by this Item. Meet the requirements specified in Section 441.3.2.5.1., “Radiographic Testing (RT),” for radiograph film quality.

4.3.8 Corrections. When welding is unsat isfactory or indicates inferior workmanship, the Engineer will require

corrective measures and approve the subsequent corrections. Use oxygen gouging or arc -air gouging when required to remove part of the weld or base metal. Back -gouge splices in beams and girders or cut out defective welds using arc -air gouging by a welder qualified to make beam and girder splices. Slope the sides of the area to be welded enough to permit depositing new metal w here corrections require depositing additional weld metal. Use a smaller electrode than that used for the original weld where corrections require depositing additional weld metal. Clean surfaces thoroughly before re- welding. Remove cracked welds completely and repair. Remove the weld metal for the length of the crack if crack length is less than half the length of the weld plus 2 in. beyond each end of the crack, and repair. Restore the original conditions where work performed after making a deficient weld has made the weld inaccessible or has caused new conditions mak ing the correction of the deficiency dangerous or ineffectual by removing welds, members, or both before making the necessary corrections; otherwise, compensate for the deficiency by performing additional work in conformance with a revised and approved des ign. Cut apart and re- weld improperly fitted or misaligned parts. Straighten members distorted by the heat of welding using mechanical means or the carefully supervised application of a limited amount of localized heat. Do not let heated areas exceed 1,200°F as measured by temperature- indicating crayons or other approved methods for steel up to 65,000- psi yield strength. Do not let heated areas exceed 1,100°F for higher -strength steels. Keep parts to be heat -straightened substantially free of stress from ex ternal forces except when mechanical means are used with the application of heat. Before straightening, submit a straightening procedure to the Engineer for approval. Correct defective or unsound welds either by removing and replacing the entire weld or as follows . 4.3.8.1. Excessive Convexity. Reduce to size by grinding off the excess weld metal, leaving a smooth profile. 4.3.8.2. Shrinkage Cracks, Cracks in Base Metal, Craters, and Excessive Porosity. Remove defective portions of base and weld metal down to sound metal, and replace with additional sound weld metal. 689 4.3.8.3. Undercut, Undersize, and Excessive Concavity. Clean and deposit additional weld metal. 4.3.8.4. Overlap and Incomplete Fusion . Remove and replace t he defective portion of weld. 4.3.8.5. Slag Inclusions . Remove the parts of the weld containing slag, and replace them with sound weld metal. 4.3.8.6. Removal of Base Metal D uring Welding. Clean and form full size by depositing additional weld metal using stringer beads.

4.4 Shear Stud Welding. Weld shear studs to steel surfaces and perform preproduction and production tests as

required in AASHTO/AWS D1.5.

4.5 Welding Reinforcing Steel . Splice reinforcing steel by welding only at locations shown on the plans. Before

welding galvaniz ed rebar , remove the zinc coating at least 1 in. from either side of the intended weld zone by grinding or equivalent means. After welding, repair the galvanized zinc coating damage in the welded area in accordance with Item 445, “Galvanizing.”

4.5.1 Base Metal . Provide weldable reinforcing steel in accordance with Item 440, “Reinforcement for Concrete.”

4.5.2 Preheat and Interpass Temperature. Minimum preheat and interpass temperatures are shown in Table 5.

Preheat reinforcing steel when it is below the listed temperature for the size and carbon equivalency range of the bar being welded so that the cross -section of the bar is above the minimum temperature for at least 6 in. on each side of the joint. Allow bars to cool naturally to ambient temperature after welding is complete. Do not accelerate cooling. Table 5 Minimum Preheat and Interpass Temperature for Reinforcing Steel Carbon Equivalent Range (%) Size of Reinforcing Bar ( No.) Temperature (°F) Up to and including 0.40 Up to 11 inclusive None 14 and 18 50

0.41 through 0.45 inclusive Up to 11 inclusive None

14 and 18 100

0.46 through 0.55 inclusive Up to 6 inclusive None

7 to 11 inclusive 50 14 and 18 200 Unknown Up to 18 inclusive 500 Base the preheat and interpass temperatures for widening projects on the existing reinforcing steel and the requirements shown in Table 5.

4.5.3 Joint Types . Use butt splices for all No. 7 and larger bars. Use lap splices for No. 6 and smaller bars.

Make groove welds in lap splices at least 4 in. long and weld them on each side of the lap joint as shown in Figure 7. For No. 5 and smaller bars, weld from one side of the lap when it is impractical to weld from both sides of the joint if approved, but in this case make the weld at least 6 in. long. Make all butt splices in the flat position. Make all welds for butt splices, except horizontal welds on vertical bars, as shown in Figures 8 and 9. The backup strip is required when access to the splice is from the top only. When bars can be rotated or access to the splice is available from two sides, the double V -groove splice may be used, and this type of weld requires gouging out the root pass similar to a flange splice on structural steel. The root pass may be made using E7010 or E8010 electrodes for all double V -groove splices. Preheat the steel to 400°F, if using E7010 or E8010 electrodes, and then completely remove the root pass before welding the opposite side. Make horizontal splices on vertical bars as shown in Figure 10. Provide alignment strips as shown in Figures 9 and 10 to hold bars during welding operation. Trim alignment strips after welding is complete. Figure 7 Direct Lap Joint with B ars in C ontact Figure 8 Single V -Groove Weld in H orizontal Position Figure 9 Double V -Groov e Weld in H orizontal Position Figure 10 Double Bevel and Double V-Groove Weld s in Vertical Position

4.5.4 Radiographic Inspection. Radiograph welded butt splices at the expense of the Contractor when

designated on the plans. Follow all applicable rules and regulations for radiographic operations. Ensure welds have no cracks and that the sum of the greatest dimensions of porosity and fusion- type defects do not exceed 1/10 of the nominal bar diameter. The Engineer will examine and interpret the resulting radiographs, which become the property of the Department and remain with the Engineer.