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Collaborative assessment and comprehensive list accepted deviations from AASHTO LRFD BDS


Many State Agencies have purposeful and rational deviations from AASHTO LRFD Bridge Design Specifications (BDS).


The goal of this study is to compile State Agency deviations from AASHTO in an organized manner to serve as a resource and idea sharing document from which the States can compare and contrast their own deviations. Additionally, cases where exceptions taken by multiple states may indicate the need or opportunity for changes or updates to the AASHTO LRFD BDS. A single source document would provide a mechanism to identify these opportunities.


This study has the following benefits:

  • Collaboration between States to identify helpful substitutions to AASHTO LRFD

  • Identify indicators for changes to AASHTO LRFD

  • Evaluate regional trends

  • Facilitate knowledge sharing Assist consultants, contractors, fabricators, etc. in readily identifying State Agency preferences

Related Research:

This would be a singular, unprecedented compilation of information


The scope is to elicit a university and/or consultant, which is highly experienced in serving and working with a majority of State Agencies, such that knowledge of the AASHTO LRFD deviations are familiar to the selected researcher. Since deviations are public knowledge, there should be little barrier to implementation nor barrier to distribution of the findings. Activities will include:

  • Collection and review of State Agency Guidance and Manual documents; Alternately, receive lists of exceptions/deviations from participating State Agencies

  • Review documents for deviations from/exceptions to the AASHTO LRFD BDS

  • Development of format for categorization and presentation of findings

  • Development and distribution of final report

  • Review on 6 year basis to update changes

  • Distribute electronic copies of the report to the state bridge engineer in each state

  • Targeted presentations of the findings at each AASHTO CBS subcommittee meeting (e.g., T-10 Concrete, T-14 Steel, etc.) Categorize the findings in the report and provide recommendations regarding follow up (e.g., recommendations for needed research, recommendations regarding possible clarifications/updates to the AASHTO LRFD BDS, etc.)


This is relevant to every State Agency, and the bridge industry as a whole. This research has the potential for all to learn from each other and improve AASHTO LRFD guidance.

Sponsoring Committee:AFF20, Steel Bridges
Research Period:12 - 24 months
Research Priority:High
RNS Developer:Duncan Paterson, PE PhD
Source Info:AASHTO LRFD, publicly available State Agency bridge design guidance and manuals
Date Posted:07/16/2019
Date Modified:07/26/2019
Index Terms:Bridge design, AASHTO LRFD Bridge Design Specifications, Highway bridges, Load and resistance factor design, State departments of transportation, Specifications,
Cosponsoring Committees:AFF10, General Structures; AFF30, Concrete Bridges
Bridges and other structures

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