Project 2a: Reliability-Based Evaluation of Bridge Components for Consistent Safety Margins - UMC

The MoDOT LRFD Bridge Design Guidelines (LRFD hereafter, MoDOT, 2007) is a slightly modified version of the AASHTO LRFD Design Specifications (AASHTO, 2001) that were mandated for use in new bridge designs starting October 1, 2007. Based on structural reliability methods, the LRFD introduces a limit state design philosophy to achieve a more uniform level of safety (reliability) in new bridge design. In current practice, however, some bridge components are still designed to have different levels of safety from others due to 1) design of some bridge components are controlled by service limit state rather than strength limit state, 2) load factors for service limit state in LRFD is not well-calibrated with quantitative basis and consensus, 3) the service limit highly depends on traffic demand of a specific state. The objective of this project is to calibrate load and resistance factors in LRFD (MoDOT, 2007) to achieve a more uniform level of safety (reliability) in bridge design. The calibration of the load and resistance factors, specifically considering Missouri environment, will lead to a reduction in the up-front cost of bridges. Load factors will be calibrated to achieve two goals: 1) the bridge components should have consistent safety margin, and 2) the bridge components designed with LRFD should be compatible with components designed with LRFD which have performed well for the past years. The scope of the proposed project is: * To develop service load models and to establish service limit state criteria for Missouri condition and environment based on the past maintenance records * To calibrate the LRFD Bridge Design Guidelines (MoDOT, 2007) and to identify over-conservatively designed bridge components for overall cost reduction * To develop necessary revisions of MoDOT Standard Plans for Highway Construction for typical types of MoDOT bridges to reflect the LRFD design philosophy The outcomes of this project are a reduction in the up-front cost of bridges and a sound rationale on load factors and resistance factors for service limit state, which has been determined primarily based on engineering judgment.

• Record URL:
  http://utc.mst.edu/research/R239.html

Language

• English

Project

• Status: Completed
• Funding: $159381.00
• Contract Numbers:

  DTRT06-G-0014

  00022950

• Sponsor Organizations:

  University of Missouri, Columbia

  Agricultural Experiment Station
  Columbia, MO  United States  65201

  Missouri Department of Transportation

  1617 Missouri Boulevard
  P.O. Box 270
  Jefferson City, MO  United States  65102
• Principal Investigators:

  Orton, Sarah

• Start Date: 20080901
• Expected Completion Date: 0
• Actual Completion Date: 20100831
• Source Data: RiP Project 18901

Subject/Index Terms

• TRT Terms: Bridge design; Bridge members; Calibration; Structural analysis; Structural design
• Identifier Terms: AASHTO LRFD Bridge Design Specifications
• Uncontrolled Terms: Level of safety; Reliability-based assessment (Bridge engineering); Structural reliability
• Subject Areas: Bridges and other structures; Design; Highways;

Filing Info

• Accession Number: 01462497
• Record Type: Research project
• Source Agency: Center for Infrastructure Engineering Studies
• Contract Numbers: DTRT06-G-0014, 00022950
• Files: UTC, RIP, STATEDOT
• Created Date: Jan 3 2013 2:04PM