Following the October 17, 1989 Loma Prieta Earthquake, a large number of damaged and undamaged structural concrete bridge structures had to be assessed and evaluated for seismic repair and retrofit. The lack of consistent assessment and evaluation models prompted the formulation of the outlined procedures in a first attempt to develop a comprehensive basis for the seismic assessment and retrofit of existing bridge structures. The presented principles are currently being developed at UCSD into consistent assessment design models in cooperation with the California Department of Transportation.