Vibration Control of Seismically Excited Adjacent Buildings Prone to Pounding by Use of Friction Dampers

Mitigation of pounding between closely spaced building structures, subjected to earthquake excitation, by interconnecting them by friction dampers is investigated. Considering the pounding force and damper frictional force, the non-linear equations of motion of two connected single-degree-of-freedom (SDOF) structural systems subjected to recorded earthquake base motions are formulated and solved for the stick and slip phases. The pounding and damper frictional forces are represented by the Hertzian impact model and by the Coulomb friction model, respectively. Different combinations of structural time periods are considered to examine the effect of the relative flexibility of the adjacent structures on the pounding occurrence and on the performance of the damper. Results indicate that by appropriately selecting the slip force in the friction damper, it is possible to completely mitigate pounding. However, this may entail an increased displacement of the stiffer structure over that of the uncontrolled response. It is seen that a judicious choice of the damper slip force will provide substantial pounding reduction, even in case of large earthquakes, while constraining the displacements to within the uncontrolled values.