The primary objective of this research was to develop evaluation procedures for steel bridges of different types and for prestressed concrete girder bridges based on the load and resistance factor design (LRFD) methodology. These procedures were then combined with those developed in NCHRP Project 10-15 for reinforced concrete bridges in order to create comprehensive evaluation guidelines for all typical bridge types. The guidelines were prepared in a format suitable for incorporation into the AASHTO Manual for Maintenance Inspection of Bridges.

The first phase of research (development of evaluation procedures for steel girder and prestressed girder bridges) was completed in 1987. The results from this phase of work were published as NCHRP Report 301, "Load Capacity Evaluation of Existing Bridges."

The second phase of research included the combination of the Project 10-15 and 12-28(1) guidelines, and the development of training materials and example problems demonstrating the use of the new guidelines. The combined guidelines were published in 1989 as AASHTO Guide Specification for Strength Evaluation of Existing Steel and Concrete Bridges.