Designing water dampers for suppressing along-wind and cross-wind building vibration

The purpose of this paper is to establish some simple and useful water damper design formulas for wind-Induced vibration control of tall buildings. A total of four different types of water dampers (CTLD, RTLD, TLCD and LCVA) are considered in this study. These four types of water dampers represent a stream of reliable and effective passive control devices which are well studied and ready to be used on flexible buildings and structures. A set of unified equations of motion for the building-damper system under wind-Induced excitation are presented. First the along-wind and the cross-wind responses for a tall building are revisited and derived. The effect of water dampers on the suppression of building response is then demonstrated through establishing an equivalent damping ratio for the water dampers. It is seen that the addition of water dampers would increase the damping ratio of the building and thus reduce its wind-induced vibration. A set of formulas for the optimal properties and the optimal equivalent damping ratio of the water dampers are derived in simple forms. These simple formulas can be used easily by the structural engineers to evaluate the effect and to practically design water Dampers for their buildings.