Recent failures of gusset plate bridge connections and the current national urgency to properly design and rate gusset truss connection points to the need for further analytical and experimental investigations to verify and/or modify existing procedures, and to provide guidance to the bridge engineers for the proper design and rating of riveted and bolted gusset-plated connections. In addition, the lack of uniformity and best practices in the design and load rating of gusset connections results in confusion, unknown safety hazards, and possibly unnecessary checks. There is a pressing urgency to develop safe guidelines and procedures to help bridge owners design and load rate steel bridge gusset connections. These guidelines must be verified to ensure that connections are not only properly designed and rated but most importantly without imposing unnecessary burdens. The new guidelines are expected to assure the safety of new and existing bridges and simplify design and rating to avoid unfavorable failure modes.
To develop guidelines, specifications, and examples for the load and resistance factor design and rating of gusset connections.
Recommendation that gusset plates be included in the load rating process and the data produced in this project provided the justification to support the resistance equations for the various failure modes. The research focused primarily on buckling and shear failure modes of gusset plates, including the effects of section loss, multilayered plates, and edge stiffening. The project also presented a comprehensive review of past literature on the strength of hot-driven rivets. Resistance equations were defined and calibrated load factors are provided for each equation according to a load and resistance factor philosophy. Two-column draft specification language was provided for ready adoption into the American Association of State Highway Transportation Officials (AASHTO) LRFD Bridge Design Specifications and the AASHTO Manual for Bridge Evaluation. [Source: FHWA, PMSS Database (2013)]