Condition factor calibration for load and resistance factor rating of steel girder bridges : final report.

Details

• Creators:
  Steelman, Joshua ; Shakya, Pranav
• Corporate Creators:
  University of Nebraska--Lincoln. Dept. of Civil Engineering ; Nebraska Transportation Center
• Corporate Contributors:
  Mid America Transportation Center ; United States. Department of Transportation. University Transportation Centers (UTC) Program ; Nebraska. Dept. of Roads
• Subject/TRT Terms:
  • Ratings
  • Reliability
  • Calibration
  • Girder bridges
  • Inspection
  • Load factor
  • Uncertainty Steel girder
  • LRFR
  • condition factor
• Publication/ Report Number:
  SPR-P1 (16) M043
• Resource Type:
  Tech Report
• Geographical Coverage:
  United States
• Edition:
  Final report, July 2015-December 2016
• Corporate Publisher:
  Nebraska Transportation Center
• Abstract:
  Load and Resistance Factor Rating (LRFR) is a reliability-based rating procedure ; complementary to Load and Resistance Factor Design (LRFD). The intent of LRFR is to provide ; consistent reliability for all bridges regardless of in-situ condition. The primary difference ; between design and rating is the uncertain severity and location of deterioration, including the ; potential future loss of strength for an element already evidencing deterioration. Ostensibly, ; these uncertainties are addressed by applying an additional strength reduction factor: the ; condition factor, ϕc. Currently, condition factors are nominally correlated to the condition of the ; member, which can be Good, Fair, or Poor. However, definitions of these condition categories ; are deferred to inspection documents, which themselves lack clear, objective definitions. ; Furthermore, lack of guidance to account for the location and extent of deterioration exacerbates ; confusion in the methodology to appropriately assign condition factors. These ambiguities cause ; incoherence between inspection and rating processes by introducing additional uncertainty. The ; additional uncertainty skews load ratings, sometimes producing ratings with unintended ; conservativism, and sometimes overestimating the safe load-carrying capacity of a bridge. This ; study presents a calibration of ϕc to be used with steel girder bridges, accounting for uncertainty ; due to non-uniform deterioration throughout transverse sections, unquantified severity of section ; loss associated with condition states, lack of knowledge of the longitudinal location(s) of the ; deterioration, and the likelihood of further deterioration over the next inspection cycle for ranges ; of section loss for each condition. The proposed condition state definitions and implementation ; methodology are intended to improve uniformity in the inspection process and produce bridge ; load ratings that are more consistent with the target reliability intended by the LRFR rating ; procedure.
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• Format:
  PDF
• Download URL:
  https://rosap.ntl.bts.gov/view/dot/32678/dot_32678_DS1.pdf
• File Type:
  [PDF - 6.00 MB]
• Collection(s):
  University Transportation Centers ; US Transportation Collection
• Main Document Checksum:
  urn:sha-512:b455b92387579e19d852082625a3ead817677fbcacbf51428eba229f7c15ba8e02485d0f1c0a54c5b5baf756e729fbd599ec9c993120ce973fa846907ce88283