Passive damping devices for earthquake protection of bridges and buildings

This contribution describes the practical application of tuned mass control systems (TMCS) to bridges and buildings.Besides the experimental verification of significant reduction effects, results the results of a theoretical analysis that document the achievable improvements on the seismic response even in case of large structural damping ratios, is presented.Optimization approaches for these passive control systems will be discussed as well as practical considerations regarding the resulting specification of the TMCS.For the discussion, theoretical approaches will be introduced and results of additional numerical calculations will be presented.Design considerations for the selection of the parameters of the TMCS that take into account the nonlinearities due to the possible decrease of structural stiffness and the increase of structural damping due to cracks and local damages, will be discussed as well.In the context of TMCS, two example projects will be introduced.One example explains the application of TMCS systems to a low damped elevated bridge structure and design solutions for these systems are presented as well as in-situ test methodologies to verify the increase of structural damping.The other example describes the application of TMCS systems as part of a consolidation strategy to successfully retrofit a large RC-structure / masonry wall building.Results of numerical calculations -verified by insitu ambient vibration measurements -that examine the reduction effect of the TMCS in combination with additional measures will be shown together with cost effective design solutions.