Design decisions for highway structures can utilize probability and statistics to express uncertainties in vehicle loading, analysis, strength and construction control. Structural reliability research is described to provide design codes with consistent risk levels and optimal designs. A detailed reliability approach is presented for deriving load and performance factors for steel element fatigue design. The uncertainties in truck weight, volume, headway, strength distribution (analysis), impact and fatigue life are included. The fatigue load model is extended to strength design by considering two behavior levels. The first level utilizes a limit state format with element-oriented load and performance factors derived for components with failure criteria such as maximum moment. Ultimate strength is recognized in a second level check with system coefficients based on the ratio of the load causing significant bridge distress to the limit state load. Code oriented research is described to derive system coefficients for various types of bridge structures using nonlinear and ultimate load analysis. The goal is to utilize the load margin between an element limit state and major bridge damage to contain load uncertainties in future load growth and overweight vehicle operations. The sparce load data available has inhibited introduction of reliability oriented specifications. A project is desribed for undetected weighing of vehicles in motion using instrumented highway bridge girders. The field results show its feasibility and opportunities for filling in missing data on load history and overweight vehicles. /Author/

Media Info

  • Media Type: Print
  • Features: Figures; References; Tables;
  • Pagination: pp 198-206
  • Monograph Title: Bridge Engineering. Volume 1
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00183765
  • Record Type: Publication
  • ISBN: 0309026962
  • Files: TRIS, TRB
  • Created Date: Dec 3 1978 12:00AM