ABSTRACT
Tuned Mass Dampers (TMD) and semi-active devices have significant capability to add supplemental damping and reduce structural response, particularly under earthquake loading. In this study semi-active devices are used in conjunction with spring devices to isolate the upper stories of a structure, alleviating the need for a large extra mass. Combining semi-active dampers with the timed mass damper design/method to create a semi-active TMD system (SATMD) has some major advantages over pure passive TMD systems, these include; providing control over a broad range of structural natural frequencies and being easier to design. The statistical performance measures are evaluated for TMD and SATMD designs for 20 seismic records within three earthquake suites. Mean reductions up to 30% are seen in peak displacements of the main structure with reductions achieved for most of the ground motion record. The 1st standard deviation spread of results in each suite is three to four times smaller for a SATMD system than a passive TMD, indicating their ability to respond more effectively to a broad range of inputs.
