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Compilation of Agency Approved Exceptions to/from AASHTO LRFD BDS

Description:

State Highway Agencies (SHA) across the country are developing exceptions to the AASHTO LRFD Bridge Design Specifications (AASHTO LRFD BDS). However, these exceptions are being developed individually by the respective SHAs. Information sharing, while facilitated by AASHTO, is not overly effective, nor thorough, and State Bridge Engineers and their staff (including consultants) often resort to a case by case analysis and evaluation of project specific exceptions to the AASHTO LRFD BDS. This individualized approach to exceptions to the AASHTO LRFD BDS can be duplicative and does not harness the collective knowledge and experience that exists across the country. As SHAs continue to be asked to “do more with less” and find unique solutions to problems, learning from others is an efficient and effective approach.

Objective:

The goal of this study is to compile SHA approved exceptions to the AASHTO LRFD BDS in an organized manner to serve as a resource and idea sharing document for SHAs to utilize when developing structural design solutions for projects. In addition, this compilation would also serve as a continuous improvement mechanism for the AASHTO Committee on Bridges and Structures as it would identify areas where improvements to the AASHTO LRFD BDS are warranted. A single source document would provide a mechanism to identify these opportunities.

Benefits:

The proposed research is urgently needed to provide SHAs the shared expertise of their cohort group of State Bridge Engineers on the rationale, logic and experience for accepting new materials, new technology and new methods of analysis and design that are either not accounted for or not allowed under the existing AASHTO LRFD BDS. Based on the rapid exchange of information, State Bridge Engineers need to be able to appropriately respond to inquiries and/or adapt their standards to allow alternative structural solutions being designed and constructed by other SHAs.

In addition, this compilation of SHA approved exceptions to the AASHTO LRFD BDS will provide the AASHTO Committee on Bridges and Structures a road map for where future research is needed to continually improve the AASHTO LRFD BDS.

The successful research will meet AASHTO Strategic Plan for Bridges and Structures in following aspects:

  • Maintain and Enhance AASHTO Specifications for Improved Structural Performance;

  • Enhance and Optimize Structural Systems;

  • Enhance National Policy;

Related Research:

There is no related research ongoing or proposed.

Tasks:
  • Review State DOT Guidance and Manual documents;
  • Develop a questionnaire to request exceptions from SHAs
  • Compile and review documents for exceptions to the AASHTO LRFD BDS
  • Identify underlying reasons and trends for exception
  • Development of a report format for categorization and presentation of findings
  • Development and distribution of final report
  • Recommend proposed methodology for tracking future approved exceptions
Implementation:

The scope is to elicit a university and/or consultant, which is highly experienced in serving and working with SHAs, such that a working knowledge of the AASHTO LRFD BDS, and State specific exceptions are familiar to the selected researcher. Since AASHTO LRFD BDS exceptions are often published in the respective SHA Bridge Design manual, they are generally public knowledge and there should be little barrier to identification nor barrier to distribution of the findings. Activities will include:

(1) Review State DOT Guidance and Manual documents;

(2) Develop a questionnaire to request exceptions from SHAs

(3) Compile and review documents for exceptions to the AASHTO LRFD BDS

(4) Identify underlying reasons and trends for exception

(5) Development of a report format for categorization and presentation of findings

(6) Development and distribution of final report

(7) Recommend proposed methodology for tracking future approved exceptions

The Implementation Plan will include but not be limited to the following:

(1) Presentation to the AASHTO Committee on Bridges and Structures;

(2) Provide a final report documenting the entire project, incorporating all other specified deliverables of the research;

(3) Deliver a webinar to inform practitioners of the compilation of exceptions to the AASHTO LRFD BDS;

(4) Presentations at TRB, International Bridge Conference, and other practitioner related meetings and conferences; and

(5) Recommendations on needs and priorities for additional research.

Relevance:

Resource and idea sharing document for State Highway Agencies to utilize when developing structural design solutions for projects. In addition, this compilation would also serve as a continuous improvement mechanism for the AASHTO Committee on Bridges and Structures as it would identify areas where improvements to the AASHTO LRFD BDS are warranted. A single source document would provide a mechanism to identify these opportunities.

Sponsoring Committee:AFF10, General Structures
Research Period:12 - 24 months
Research Priority:High
RNS Developer:Richard Dunne, PE (AFF10 Chair), Duncan Paterson, PE, HDR
Source Info:This research needs statement is submitted by the TRB General Structures Committee AFF10 in collaboration with the TRB Committee on Steel Bridges AFF20 and the TRB Committee on Concrete Bridges AFF30. AASHTO Committee on Bridges and Structures Identified as potentially interested AASHTO Committee.
Date Posted:03/29/2019
Date Modified:04/04/2019
Index Terms:Load and resistance factor design, Bridge design, State highway departments, Highway bridges,
Cosponsoring Committees: 
Subjects    
Highways
Administration and Management
Design
Bridges and other structures

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