A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering, School of Civil Engineering

Thesis (M.Eng.) - Asian Institute of Technology, 2000

Metallic dampers, when incorporated into a structure, provide one of the most effective energy dissipation mechanisms during an earthquake. A study of improvement of seismic performance of multi-story frame buildings by using metallic dampers for wide range of structural period is presented. Frame-type buildings with different number of stories are modeled as single-bay shear frame buildings. The structures are subjected to a single earthquake ground motion record and their seismic responses are determined by performing nonlinear dynamic analyses through DRAIN-2DX Program. At the beginning, the higher mode effects on seismic responses of these structures are investigated. The results confirm that the higher mode effects are significant and cause the high localization of structural damage in first few stories for long period structure. To reduce the structural damage of these structures, the metallic dampers that were designed in conventional way are selected. The results show that metallic dampers, which were designed in conventional way, cannot effectively reduce the structural damage of long period multi-story frame buildings. A more effective way to design the metallic dampers to reduce the seismic response of structures for wide range of natural period is introduced. By employing this new concept, the metallic dampers can effectively reduce the seismic response of long period structures.