STRENGTHENING CALIFORNIA'S STEEL BRIDGES BY PRESTRESSING

The Surface Transportation assistance Act of 1982 that addresses increased truck sizes and weights has exacerbated maintenance problems of existing bridges designed to meet earlier loading criteria. In 1975 California implemented the Permit Design Live Load that allows substantial increases in live loads. Strengthening existing steel bridges on the highway system, in particular those bridges on California's State Highway Extra Legal Load network (SHELL routes), has assumed a high priority. Two steps can be involved: (a) All existing steel girder bridges are screened for potential overstress by a sophisticated computer program, CURVBRG. This program, which uses a plane grid analysis, was written at the University of California at Berkeley and adapted by the Structural Research Unit of the California Department of Transportation for use by the Office of Bridge Maintenance. For the heavier live loads, CURVBRG assesses stresses and deflections much more precisely than do usual design methods. If overstress is indicated, step (b) is implemented. (b) Longitudinal prestressing tendons are installed to enhance moment capacity in critical areas. Structural steel may be added as necessary to achieve balanced design stresses. This has been don on seven steel girder bridges to date and is planned for a dozen more. CURBBRG is described briefly, and several examples of prestressed installations are presented. Prestressing has proven to be a quick, economical, aesthetically pleasing method of strengthening steel bridges.

• Record URL:
  • http://onlinepubs.trb.org/Onlinepubs/trr/1984/950/950v1-028.pdf
• Record URL:
  • https://scholar.google.com/scholar_lookup?title=STRENGTHENING+CALIFORNIA%27S+STEEL+BRIDGES+BY+PRESTRESSING&author=G.+Mancarti&publication_year=1984
• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/isbn/3090036593
• Supplemental Notes:
  • This paper appeared in Transportation Research Record Number 950, Volume 1, Second Bridge Engineering Conference conducted by the Transportation Research Board and the Federal Highway Administration, September 24-26, 1984. Publication of this paper sponsored by Committee on Structures Maintenance. 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:
  • Mancarti, Guy D
• Conference:
  • Bridge Engineering Conference, 2nd, 1984, Washington, DC, USA
• Publication Date: 1984

Media Info

• Media Type: Print
• Features: Figures; Photos; References; Tables;
• Pagination: pp 183-187
• Monograph Title: Second bridge engineering conference. volumes 1 and 2
• Serial:
  • Transportation Research Record
  • Issue Number: 950
  • Publisher: Transportation Research Board
  • ISSN: 0361-1981

Subject/Index Terms

• TRT Terms: Aesthetics; Computer programs; Deflection; Girder bridges; Laws; Live loads; Metal bridges; Prestressing; Screenings; Size; Size and weight regulations; Steel bridges; Strength of materials; Structural strengthening; Tendons; Weight
• Geographic Terms: California
• Subject Areas: Bridges and other structures; Design; Highways; Law; I24: Design of Bridges and Retaining Walls;

Filing Info

• Accession Number: 00390865
• Record Type: Publication
• ISBN: 03090036593
• Files: TRIS, TRB
• Created Date: Dec 30 1984 12:00AM