Laserfiche WebLink
• Electrodes used for welding shall meet the minimum Charpy V-notch impact requirement of 27°J at—20°C. <br /> • For welding of bars conforming to the requirements of ASTM Designation: A 615/A 615M, Grade 280 or <br /> Grade 420,the requirements of Table 5.2, "Minimum Preheat and Interpass Temperatures,"of AWS D 1.4 are superseded by <br /> the following: <br /> The minimum preheat and interpass temperatures shall be 200°C for Grade 280 bars and 300°C for Grade 420 bars. <br /> Immediately after completing the welding, at least 150 mm of the bar on each side of the splice shall be covered by an <br /> insulated wrapping to control the rate of cooling. The insulated wrapping shall remain in place until the bar has cooled <br /> below 90°C. <br /> • When welding different grades of reinforcing bars, the electrode shall conform to Grade 280 bar requirements and <br /> the preheat shall conform to the Grade 420 bar requirements. <br /> • In the event that any of the specified preheat,interpass,and post weld cooling temperatures are not met,all weld and <br /> heat affected zone metal shall be removed and the splice rewelded. <br /> • Welding shall be protected from air currents, drafts,and precipitation to prevent loss of heat or loss of arc shielding. <br /> The method of protecting the welding area from loss of heat or loss of arc shielding shall be subject to approval by the <br /> Engineer. <br /> • Reinforcing bars shall not be direct butt spliced by thermite welding. <br /> • Procedures to be used in making welded splices in reinforcing bars, and welders employed to make splices in <br /> reinforcing bars, shall be qualified by tests performed by the Contractor on sample splices of the type to be used, before <br /> making splices to be used in the work. <br /> 52-1.08B(3) Resistance Butt Welds <br /> • Shop produced resistance butt welds shall be produced by a fabricator who is approved by the Transportation <br /> Laboratory. The list of approved fabricators can be obtained from the Department's internet site or by contacting the <br /> Transportation Laboratory directly. <br /> • Before manufacturing hoops using resistance butt welding, the Contractor shall submit to the Engineer the <br /> manufacturer's Quality Control (QC)manual for the fabrication of hoops. As a minimum, the QC manual shall include the <br /> following: <br /> A. The pre-production procedures for the qualification of material and equipment. <br /> B. The methods and frequencies for performing QC procedures during production. <br /> C. The calibration procedures and calibration frequency for all equipment. <br /> D. The welding procedure specification(WPS)for resistance welding. <br /> E. The method for identifying and tracking lots. <br /> 52-1.08C Service Splice and Ultimate Butt Splice Testing Requirements <br /> • The Contractor shall designate in writing a splicing Quality Control Manager (QCM). The QCM shall be <br /> responsible directly to the Contractor for 1)the quality of all service and ultimate butt splicing including the inspection of <br /> materials and workmanship performed by the Contractor and all subcontractors; and 2)submitting, receiving, and approving <br /> all correspondence,required submittals,and reports regarding service and ultimate splicing to and from the Engineer. <br /> • The QCM shall not be employed or compensated by any subcontractor, or by other persons or entities hired by <br /> subcontractors, who will provide other services or materials for the project. The QCM may be an employee of the <br /> Contractor. <br /> • Testing on prequalification and production sample splices shall be performed at the Contractor's expense, at an <br /> independent qualified testing laboratory. The laboratory shall not be employed or compensated by any subcontractor, or by <br /> other persons or entities hired by subcontractors who will provide other services or materials for the project, and shall have <br /> the following: <br /> A. Proper facilities, including a tensile testing machine capable of breaking the largest size of reinforcing bar to be <br /> tested with minimum lengths as shown in this section. <br /> B. A device for measuring the total slip of the reinforcing bars across the splice to the nearest 25 gm,that,when placed <br /> parallel to the longitudinal axis of the bar is able to simultaneously measure movement across the splice at <br /> 2 locations 180 degrees apart. <br /> C. Operators who have received formal training for performing the testing requirements of ASTM Designation: A 370 <br /> and California Test 670. <br /> Contract No. 10-0M7104 <br /> 37 <br />