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:
  Calibration Condition Factor Girder Bridges Inspection Load Factor LRFR Ratings Reliability Uncertainty Steel Girder
• 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.
  
  
• Format:
  PDF
• Collection(s):
  University Transportation Centers US Transportation Collection
• Main Document Checksum:
  urn:sha-512:b455b92387579e19d852082625a3ead817677fbcacbf51428eba229f7c15ba8e02485d0f1c0a54c5b5baf756e729fbd599ec9c993120ce973fa846907ce88283
• Download URL:
  https://rosap.ntl.bts.gov/view/dot/32678/dot_32678_DS1.pdf
• File Type:
  [PDF - 6.00 MB ]