FATIGUE LOAD SPECTRA FOR STEEL GIRDER BRIDGES. RESEARCH REPORT

The project objective is to develop the procedure for evaluation of live load spectra on Michigan bridges. Evaluation procedures are also provided for steel girder bridges subjected to fatigue. The study involves both analytical and experimental efforts. The live load model is developed on the basis of weigh-in-motion (WIM) measurements, truck counts, truck surveys, and statistical analysis. Fatigue analysis focuses on the prediction of live load spectra. Field testing equipment included two data acquisition systems, two portable computers, a van, a power generator, and other hardware. Most of the field equipment was specially purchased for this project. There is very little truck weight data available. Studies performed in other states did not provide reliable results, therefore in this project the major source of actual truck loads is WIM measurements. This progress report summarizes the load measurements performed on two bridges in 1992. The equipment was calibrated using trucks provided by the University of Michigan Transportation Research Institute (UMTRI). Results indicate a relatively large number of heavy trucks, in excess of 200,000 pounds gross vehicle weight. Dynamic stress/strain data have been collected at two bridges and at one of the bridges the stress spectra were collected simultaneously with the WIM data. This information will be useful in correlating the WIM information with dynamic stress/strain data for fatigue evaluation of highway girder bridges. Fatigue cracks are a common form of deterioration. Structural behavior depends on load frequency and magnitude, therefore fatigue load spectra are determined on the basis of ADTT, WIM measuremnets, and dynamic stress/strain histories.

• Corporate Authors:

  University of Michigan Transportation Research Institute

  Great Lakes Center for Truck Transportation Research, 2901 Baxter Road
  Ann Arbor, MI  United States  48109-2150
• Authors:
  • LAMAN, J A
  • Nowak, A S
• Publication Date: 1992-12

Language

• English

Media Info

• Features: Figures; References; Tables;
• Pagination: 61 p.

Subject/Index Terms

• TRT Terms: Cracking; Databases; Deformation curve; Fatigue (Mechanics); Field tests; Girder bridges; Live loads; Measurement; Steel; Steel bridges; Structural analysis; Structural mechanics; Trucks; Trucks by weight; Weigh in motion; Weight
• Uncontrolled Terms: Structural behavior
• Old TRIS Terms: Fatigue load spectra; Stress strain data
• Subject Areas: Bridges and other structures; Design; Highways; Motor Carriers; I24: Design of Bridges and Retaining Walls;

Filing Info

• Accession Number: 00628904
• Record Type: Publication
• Report/Paper Numbers: GLCTTR 12-92/2
• Files: TRIS
• Created Date: Apr 23 1993 12:00AM