HEAVY LOADS ON PRESTRESSED GIRDERS: THE PROBABILITY OF FLEXURAL CRACKING

Bridge engineers often need to determine the maximum safe load that may be allowed to pass over a prestressed concrete bridge. Frequently the need for the load to pass is urgent, requiring a swift but accurate evaluation of safety. Many times the maximum load is governed by flexural cracking, and the bridge must be analyzed to find the cracking moment capacity of the girders. A conventional bending analysis uses deterministic strength properties even though properties such as concrete strength and prestress force are random variables. Because of this, a conventional load capacity analysis cannot reveal the probability of failure (i.e., by flexural cracking) associated with the passage of an extreme load. Therefore, bridge engineers have been forced to try to account for the probability of failure by a combination of experience and engineering judgement. This approach is sometimes disquieting for those engineers required to set load limits, issue overload permits, or approve large temporary construction loads. A computer program was written to use a very accurate analytical model and probabilistic methods to calculate a population of cracking moment capacities, rather than a single, deterministic value. Using this data and information about the extreme load moment, the engineer can calculate an associated probability of cracking failure. This result along with other information can be used to help the engineer in making a final decision about the safety of the passage of an extreme load.

• Record URL:
  http://onlinepubs.trb.org/Onlinepubs/trr/1991/1290vol1/1290-019.pdf
• Record URL:
  https://scholar.google.com/scholar_lookup?title=HEAVY+LOADS+ON+PRESTRESSED+GIRDERS%3A+THE+PROBABILITY+OF+FLEXURAL+CRACKING&author=V.+Geidl&publication_year=1991
• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/isbn/0309050677
• Supplemental Notes:
  • This paper appears in Transportation Research Record No. 1290, Third Bridge Engineering Conference, March 10-13, 1991, Denver, Colorado, Volume 1. 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:
  • Geidl, Verne A
• Conference:
  • Bridge Engineering Conference, 3rd, 1991, Denver, Colorado, USA
  • Location: Denver Colorado, United States
  • Date: 1991-93-10 to 1991-3-13
• Publication Date: 1991

Media Info

• Features: Figures; References; Tables;
• Pagination: p. 172-178
• Monograph Title: Third Bridge Engineering Conference: Papers Presented at the Third Bridge Engineering Conference, March 10-13, 1991, Denver, Colorado
• Serial:
  • Transportation Research Record
  • Issue Number: 1290
  • Publisher: Transportation Research Board
  • ISSN: 0361-1981

Subject/Index Terms

• TRT Terms: Bearing capacity; Computer programs; Concrete; Cracking; Flexural strength; Girders; Loading and unloading; Oversize loads; Permits; Prestressed concrete; Probability; Safety; Safety factors
• Uncontrolled Terms: Concrete cracking; Overloads; Probabilistic analysis
• Old TRIS Terms: Heavy load; Safe bearing capacity
• Subject Areas: Bridges and other structures; Data and Information Technology; Design; Highways; Safety and Human Factors; I24: Design of Bridges and Retaining Walls;

Filing Info

• Accession Number: 00611131
• Record Type: Publication
• ISBN: 0309050677
• Files: TRIS, TRB
• Created Date: Jul 31 1991 12:00AM