On the amount of tuned mass to be added for the reduction of the shedding-induced response of chimneys

Tuned mass dampers are commonly used to reduce the shedding-induced response of chimneys. In this paper, criteria for the choice of the amount of tuned mass to be added are presented. Collapse, displacement and fatigue limit states are considered. As a first step, the minimum additional mass required to prevent vortex shedding lock-in is evaluated. In a second stage, the additional mass required to limit the stable motion to a prescribed RMS displacement is computed, including the effect of errors in the tuning of the device. Finally, expressions to evaluate the fatigue life of the chimney are presented. An application to a particular chimney is used to illustrate the procedures and to compare the requirements, in terms of additional mass, related to the three different limit states.