Quantitative Approach to Rapid Seismic Evaluation of Slab-on-Girder Steel Highway Bridges

Abstract

A quantitative approach follows for developing a methodology for the rapid seismic evaluation and ranking of slab-on-girder steel highway bridges. In the development of this methodology, analytical expressions are introduced to calculate the seismically induced forces and displacements in bridge components, first assuming that damage to bearings is not acceptable and then removing this constraint. In the latter case, the superstructure is assumed to become unrestrained and slide on its supports. The seismic screening of the bridges is based on the calculation of a ranking index defined as the product of an importance index and overall damage index. Unlike other existing methodologies, the overall damage index of the structure is determined considering the impact of damage to each component on the successive failure of other components and structure as a whole. A cut-off mechanism is introduced to prevent the potentially undue impact some dominating societal aspects could have on the ranking of existing bridges with otherwise excellent seismic-resistance adequacy. The proposed methodology also quantitatively addresses the risk inherent to all seismic hazard zones.