AASHTO LRFDSEIS-3

The scope of the AASHTO Guide Specifications for LRFD Seismic Bridge Design covers the design and construction of new conventional bridges to resist the effects of earthquake motions, and applies to bridges not classified as Critical or Recovery. The title of the document reflects the fact that these Guide Specifications are approved as an alternate to the seismic provisions in the AASHTO LRFD Bridge Design Specifications. These Guide Specifications differ from the procedures in the AASHTO LRFD Bridge Design Specifications in the use of displacement-based design procedures, instead of the traditional, force-based design method. Also included are detailed guidance and commentary on earthquake-resisting elements and systems, global design strategies, demand modeling, capacity calculation, liquefaction effects, and risk-targeted ground motions. Similar to the LRFD force-based design method, capacity design procedures underpin the Guide Specifications’ methodology, and these procedures include prescriptive detailing for plastic hinging regions and design requirements for capacity protection of those elements that should not experience damage.