Details:

• Creators:
  Kwon, Oh-Sung ; Orton, Sarah ; Salim, Hani ; Kim, Eungsoo ; Hazlett, Tim

  Kwon, Oh-Sung ; Orton, Sarah ; Salim, Hani ; Kim, Eungsoo ; Hazlett, Tim Less -
• Corporate Creators:
  Missouri University of Science and Technology ; University of Missouri--Columbia

  Missouri University of Science and Technology ; University of Missouri--Columbia Less -
• Subject/TRT Terms:
  [+]

  Bridges Bridges--Live Loads Bridges--Missouri Calibration Design Load Live Loads Load Factor Load Factor Design Traffic Flow Traffic Volume Trucks--Weight Vehicle Weight Weigh-in-motion Systems Weigh In Motion
• Publication/ Report Number:
  OR 11 - 003
• Resource Type:
  Tech Report
• Geographical Coverage:
  Missouri
• Edition:
  Final report.
• Corporate Publisher:
  Missouri. Dept. of Transportation. Organizational Results
• Abstract:
  The Load and Resistant Factor Design (LRFD) approach is based on the concept of structural reliability. The approach is
  
  more rational than the former design approaches such as Load Factor Design or Allowable Stress Design. The LRFD
  
  Specification for Bridge Design has been developed through 1990s and 2000s. In the development process, many factors were
  
  carefully calibrated such that a structure designed with LRFD can achieve a reliability index of 3.5 for a single bridge girder
  
  (probability of failure of about 2 in 10,000). As the initial development of the factors in the LRFD Specification was intended to
  
  be applied to the entire nation, state-specific traffic conditions or bridge configuration were not considered in the development
  
  process. In addition, due to lack of reliable truck weigh data in the early 1990s in the U.S., the truck weights from Ontario,
  
  Canada measured in the 1970s were used for the calibration. Hence, the reliability of bridges designed with the current LRFD
  
  specification needs to be evaluated based on the Missouri-specific data and the load factor needs to be re-calibrated for optimal
  
  design of bridges.
  
  The objective of the study presented in this report is to calibrate the live load factor in the Strength I Limit State in the
  
  AASHTO LRFD Bridge Design Specification. The calibration is based on the Missouri-specific data such as typical bridge
  
  configurations, traffic volume, and truck weights. The typical bridge configurations and the average daily truck traffic of the
  
  bridges in Missouri are identified from statistical analyses of 2007 National Bridge Inventory. The Weigh-In-Motion (WIM) data
  
  from 24 WIM stations in Missouri are used to simulate realistic truck loads. Updated material and geometric parameters are also
  
  used to update the resistance distributions.
  
  From this study, it was found that most representative bridges in Missouri have reliability indices slightly lower than 3.5
  
  mainly due to the adopted projection method to predict 75 year load. For many bridges in rural areas with Average Daily Truck
  
  Traffic (ADTT) of 1,000 or less, the average reliability indices are higher than the average reliability index of bridges with ADTT
  
  of 5,000. This study proposes a table of calibration factors which can be applied to the current live load factor of 1.75. The
  
  calibration factor is developed as a function of ADTT such that bridge design practitioners can select a calibration factor
  
  considering the expected ADTTs of a bridge throughout its life span. Impact of the calibration factor on the up-front bridge
  
  construction cost is also presented.
  
  
• Format:
  PDF
• Funding:
  TRyy0913
• Collection(s):
  US Transportation Collection
• Main Document Checksum:
  [+]

  urn:sha256:66d09cba8f7a088d0936d1cc8686e04e646573b15d419d9331449f3e9231efda
• Download URL:
  https://rosap.ntl.bts.gov/view/dot/25620/dot_25620_DS1.pdf
• File Type:
  [PDF-2.04 MB]