Seismic Vulnerability of the Highway System

Task F3-3: Support for Guide Specification Trial Design Program 

Subject Area: Special Studies - NCHRP Project 12-49 Support 
Research Year 2

Principal Investigator(s) and Institution(s)

Ian M. Friedland, Applied Technology Council


The objective of this task is to provide technical and administrative support to the AASHTO Highway Subcommittee on Bridges and Structures (AASHTO Bridge Committee), during it's review and consideration for adoption of the specifications resulting from NCHRP Project 12-49. Task activities will include support for a trial design process to be conducted by States affiliated with the AASHTO Bridge Committee, and the identification of editorial and technical changes that will be required in the recommended specification provisions prior to adoption by AASHTO.


With funding from the MCEER Highway Project via Task F3-2, a set of Recommended LRFD Guidelines for the Seismic Design of Highway Bridges was produced by the Applied Technology Council (ATC), based on the results of the ATC/MCEER Joint Venture project which was conducted for the AASHTO-sponsored NCHRP Project 12-49. The Recommended Guidelines were presented to the AASHTO Bridge Committee during it's 2001 annual meetings; however, it was determined that the State members of the Bridge Committee had not had sufficient time to familiarize themselves with the provisions prior to the meeting. Concerns were also raised regarding the potential impact of the provisions contained in the Recommended Guidelines, since only a limited number of design calculations had been done using the new provisions.

It was therefore suggested that the AASHTO Bridge Committee initiate a program of Trial Designs by, as a minimum, members of the Committee's T-3 (Seismic Design) Technical Committee. However, there is no funding available within the AASHTO system to support this process over the next year, leading up to the 2002 meetings of the Bridge Committee. This task will therefore provide both administrative and technical support for the State members of the Bridge Committee to conduct trial designs using the Recommended Guidelines, with the hope that the trial design process will demonstrate that the provisions are ready for adoption by AASHTO in 2002.

Specifically, this task will:

  • Provide travel support for up to two meetings of all members of the Bridge Committee's T-3 Technical Committee - the first meeting will result in an agreement on the plans and procedures under which the trial design process will be conducted, and the second meeting will review the results of the program;

  • Provide technical support to the States involved in the trial design process by ensuring that questions and problems identified during the preparation of trial designs can be answered and resolved by members of the project team who developed the guidelines; and

  • Provide a mechanism for identifying specific editorial and technical problems with the Recommended Guidelines so that they can be addressed and rectified in time for the Bridge Committee to review and adopt the final set of provisions in May 2002.


  • A number of fully-documented trial designs that could be used in the preparation of a training course related to the use of the new specification provisions by MCEER or others in the near future;
  • A summary report documenting the impact of the new provisions on the bridge design process and result

Technical Challenges

The most critical technical challenge will be to ensure that a sufficient number of States agree to participate in the trial design process, so that there is a sufficient body of information available to ensure that the provisions are complete and are ready for adoption by AASHTO.


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