Lifecycle cost effectiveness of translational and pendulum tuned mass dampers for the seismic mitigation of building structures

Lifecycle cost (LCC) analysis is increasingly used by researchers and designers worldwide as a comprehensive and objective tool to evaluate the performance of structural systems, and particularly of dynamic mitigation strategies. Very recently, it has been successfully adopted to assess the cost-effectiveness of linear tuned mass dampers (TMDs) on inelastic building structures under earthquake hazard. In this paper, the analysis is extended to nonlinear TMDs of the pendulum type, where modelling nonlinearities are both geometrical (large angular displacements) and mechanical (collision against the fail-safe bumper). By analysing three benchmark structural models representative of typical office buildings in the Los Angeles area, a comparison between the translational (linear) and the pendulum (nonlinear) alternatives is presented. Results show that the cost-effectiveness of the pendulum TMD is similar to that of the translational TMD in many cases, but may be significantly diminished in the case of short-period structures and small mass ratios, particularly if premature bumping is permitted.