Proposed Modifications to AASHTO Culvert Load Rating Specifications

Over the past decade, significant state and federal resources have been expended to develop a state‐of-the-art set of reliability‐based bridge design and load rating specifications, including Load and Resistance Factor Design (LRFD) and Load and Resistance Factor Rating (LRFR). However, these design and rating methods were developed for larger bridge structures, and may result in overly conservative ratings when applied to buried culverts. Of the more than 600,000 records in the National Bridge Inventory, over 130,000 represent culverts, thus constituting a significant proportion of the nation’s bridge infrastructure.

The TRB National Cooperative Highway Research Program's Web-Only Document 268: Proposed Modifications to AASHTO Culvert Load Rating Specifications proposes modifications to the culvert load rating specifications in the Manual for Bridge Evaluation and revises the AASHTO LRFD Bridge Design Specifications accordingly.