Retrofitting an Existing Multi-Span Continuous Reinforced Concrete Highway Bridge by Using the Concept of Weakening and Viscous Damping

Abstract

Abstract It's crucial to keep bridges safe and operational all the time. They may require immediate seismic retrofitting before or after an earthquake. A solution could be using the concepts of weakening and damping, which have not been widely used in bridge applications. The weakening is achieved by isolating piers with Elastomer Bearings (EBs), and viscous dampers are added for the damping part. Since a proper damping coefficient distribution and velocity exponent are required for the concept, the study investigated an optimal velocity exponent and presented a novel iterative-based design approach for viscous damper distributions. The results revealed that Sys1 (EBs + nonlinear viscous damper) and Sys2 (EBs + linear viscous damper) lowered the maximum bending moment of the most affected pier between 77% and 89%, and 82% and 90.5%, respectively when compared to the “pier fixed” system (i.e., the piers are fixed to the deck). For the maximum deck shear force, Sys1 increased the forces between 70% and 155%, whereas Sys2 increased the forces between 17% and 77%. In conclusion, Sys2 outperformed Sys1 by lowering the piers' bending moment and resulting in lower deck shear forces. Deck shear forces could also be decreased to a tolerable level by selecting a bearing with different mechanical properties (such as a lead rubber bearing).