THE DESIGN AND WELDING OF A RIGID FRAME BENT OF ASTM A 514 STEELS FOR A RAILROAD OVERPASS

BEAUMONT, TEXAS, HAS LONG BEEN CONFRONTED WITH A CRITICAL PROBLEM OF TRAFFIC CONGESTION IN THE DOWNTOWN BUSINESS DISTRICT. FOUR MAJOR RAILROADS SERVE THE CITY AND ITS LARGE MARITIME PORT AND REFINERIES. A NETWORK OF MAIN LINES AND SPUR TRACKS IS CONCENTRATED WITHIN A TWO SQUARE MILE AREA OF THE DOWNTOWN AREA. A COMMERCIAL FIRM WAS GIVEN THE DESIGN PROBLEM OF RELOCATING RAILROAD TRACKS AND INSTALLING GRADE SEPARATIONS TO ALLEVIATE THE PROBLEM. ONE GRADE SEPARATION WAS A HEAVILY TRAVELED INTERSECTION WHERE THREE RAILROAD TRACKS CROSSED THE INTERSECTION AT A DIAGONAL. BECAUSE OF THE CITY'S LOW ELEVATION ABOVE SEA LEVEL, DEPTH OF DEPRESSED ROADWAYS MUST BE KEPT TO A MINIMUM. THE APPROACH GRADES OF THE RAILROAD TRACKS COULD NOT BE RAISED BEYOND ABOUT TWO FEET DUE TO AMOUNT OF RIGHT-OF-WAY REQUIRED. THE DESIGN ENGINEERS SOLVED THE PROBLEM OF INSTALLING A GRADE SEPARATION PROVIDING SUFFICIENT CLEARANCE WITH THE USE OF A RIGID FRAME BENT MADE OF A 514 STEELS. THE PAPER DISCUSSED THE ALTERNATES CONSIDERED FOR THE OVERPASS-UNDERPASS STRUCTURES AND THE ADVANTAGES GAINED IN USING THE RIGID FRAME BENT MADE OF A 514 STEELS. THE CHEMISTRY AND PHYSICAL PROPERTIES OF THE A 514 STEELS USED (ARMCO STEEL SSS 100 AND SSS 100A) ARE PRESENTED, ALONG WITH DATA ON FATIGUE STRENGTHS AND REPORTS OF WELDABILITY STUDIES. THE DETAILS OF WELD PROCEDURE QUALIFICATION CARRIED OUT BY THE FABRICATOR AND TEST RESULTS OBTAINED ON THE PLATES TO A MAXIMUM OF 3 1/2-IN. THICKNESS ARE REPORTED. PREHEAT CONSIDERATIONS ARE DISCUSSED. PROBLEMS CAUSED BY THE PRESENCE OF HYDROGEN ARE REVEALED WHEN INSUFFICIENT PREHEAT IS USED. THE SUCCESSFUL WELDING WHEN PROPER PROCEDURES ARE FOLLOWED OF THE SSS 100 AND SSS 100A STEELS IS SHOWN. ALL SHOP FABRICATION WAS FOLLOWED BY POST-WELD HEAT TREATMENT. THE HIGHLY RESTRAINED JOINTS AT THE KNEE OF THE RIGID FRAME BENT WERE WELDED WITH THREE WELDERS SIMULTANEOUSLY IN ORDER TO PREVENT RESTRAIN PROBLEMS. THE ERECTION OF THE RIGID FRAME BENT AND THE TWO CONTINUOUS SPANS SUPPORTED BY IT IS DESCRIBED. WELDING OPERATIONS WERE SUCCESSFUL DESPITE UNUSUALLY HEAVY RAINFALL IN THE WINTER. /AUTHOR/

• Record URL:
  http://onlinepubs.trb.org/Onlinepubs/hrr/1968/242/242-006.pdf
• Supplemental Notes:
  • Paper sponsored by Committee on Metals in Highway Structures and presented at the 47th Annual Meeting. Distribution, posting, or copying of this PDF is strictly prohibited without written permission of the Transportation Research Board of the National Academy of Sciences. Unless otherwise indicated, all materials in this PDF are copyrighted by the National Academy of Sciences. Copyright © National Academy of Sciences. All rights reserved.
• Authors:
  • Bridgefarmer, J E
  • Crick, H F
  • Hartzell, R L
• Publication Date: 1968

Media Info

• Media Type: Digital/other
• Features: Figures; References; Tables;
• Pagination: pp 67-83
• Monograph Title: Paints, metals, joints and polyester overlays
• Serial:
  • Highway Research Record
  • Issue Number: 242
  • Publisher: Highway Research Board

Subject/Index Terms

• TRT Terms: Bents; Chemical properties; Continuous girder bridges; Depressed highways; Frames; Grade separations; High strength steel; Metal heating; Overpasses; Physical properties; Railroad tracks; Relocation (Facilities); Stiffness; Traffic congestion; Welding
• Uncontrolled Terms: Heat treatment; Relocation; Weldability
• Old TRIS Terms: Rigid frames
• Subject Areas: Bridges and other structures; Highways; Railroads;

Filing Info

• Accession Number: 00208872
• Record Type: Publication
• Files: TRIS, TRB
• Created Date: Dec 16 1994 12:00AM