Reliability Analysis of a Suspension Bridge System Affected by Stress Corrosion Crack Propagation in a Main Cable: I. System Behavior

This paper deals with the Stress Corrosion Cracking (SCC) behavior of high strength cable wires of a suspension bridge, exposed to marine environments. Designed based on the allowable stress, main cable, tower, or girder has their own safety. However due to the differences of each safeties, the bridge system can be failed at least partly, much earlier than expected. The main objective is to compare the safety of a bridge system locally and globally. To evaluate the safety of a suspension bridge, an ultimate limit state for the local cracking in cable wires and a service limit state for the global responses of a bridge system are considered. Component reliabilities of girders have been evaluated using the response surfaces of the design variables at the selected critical sections based on the maximum shear and negative moment locations. Response Surface Method (RSM) is successfully applied for reliability analyses for this relatively small probability of failure of the complex structure, which is hard to be obtained by Monte-Carlo Simulations or by First Order Second Moment Method that can not easily calculate the derivative terms of implicit limit state functions. For the analysis of system reliability, parallel resistance system composed of girders is changed into parallel series connection system. The section of a cable wire will fail immediately when the ratio of SCC in a cable wire is larger than 24 percent. A main cable, composed of 7220 wires, fails when the ratio of SCC in a cable is larger than 60 percent. The differences of safety among the components of a bridge system can be controlled using the criterion of target reliability. Maintenance suggestions for the problems found are discussed.

• Corporate Authors:

  Transportation Research Board

  500 Fifth Street, NW
  Washington, DC  United States  20001
• Authors:
  • Nowak, Andrzej S
  • Han, Sung-Ho
  • Cho, Taejun
• Conference:
  • Transportation Research Board 86th Annual Meeting
  • Location: Washington DC, United States
  • Date: 2007-1-21 to 2007-1-25
• Date: 2007

Language

• English

Media Info

• Media Type: CD-ROM
• Features: Appendices; Figures; Photos; References; Tables;
• Pagination: 15p
• Monograph Title: TRB 86th Annual Meeting Compendium of Papers CD-ROM

Subject/Index Terms

• TRT Terms: Corrosion; Corrosion protection; Girder bridges; Monte Carlo method; Reliability; Strain measurement; Stress cracking; Suspension bridges; Suspension cables
• Uncontrolled Terms: Allowable stress; Crack propagation
• Subject Areas: Bridges and other structures; Design; Highways; I24: Design of Bridges and Retaining Walls;

Filing Info

• Accession Number: 01046007
• Record Type: Publication
• Report/Paper Numbers: 07-0847
• Files: TRIS, TRB
• Created Date: Apr 10 2007 9:22AM