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Title: AASHTO LRFD Impact Upon Bridge Stiffness and Strength
Contact: Kevin K. McGhee
Associate Director for Pavements
Project No.: 69551
Target Date: 03/09/2007
Abstract: The purpose of this research project is to evaluate the changes in bridge design that may be expected to occur with the transition to the AASHTO LRFD Specification. Specifically, the question as to whether the, now optional, deflection limits should be followed or possibly replaced with more stringent deflection limits, as well as the question as to whether the increased truck and lane loadings in the LRFD specification will lead to bridges with increased strength and stiffness will be addressed. In addition, to the extent that dynamic stresses can be measured within existing bridges chosen for redesign, it is desirable to determine whether the new LRFD specified loads and DLA values will lead to predicted vehicular load stresses consistent with the stresses measured in existing bridges The Commonwealth of Virginia is currently in the process of transitioning to the new AASHTO LRFD design specification. Several features of the new specification relevant to the proposed work include: revised vehicular load models, which will lead to larger unfactored design moments, and the reduction of the deflection limit standards to “optional” status. This study will aid in the education of bridge engineers to insure safe, cost-effective designs.

     T. T. Baber
     Jose P. Gomez

  • Pavements