Top-story mass dampers for seismic control of the first triplet of vibration modes of two-way asymmetric-plan buildings

摘要

Using an inertial part of a building structure as a tuned mass damper (TMD) has been shown to have economic advantages in terms of required materials and space for installing and operating a TMD in a building. This study suggests either designing the top story of a new asymmetric-plan building or adding a purposely designed story atop an existing asymmetric-plan building as a TMD to protect the building against earthquakes. This novel TMD, called a top-story mass damper (TSMD), is formulated using the three-degree-of-freedom modal properties of the first triplet of vibration modes of the original two-way asymmetric-plan building. The so-called first triplet of vibration modes are the first dominant modes in each of the three directions, i.e., the two horizontal translations and one vertical rotation. The proposed TSMD is intended to suppress the vibrations resulting from the first triplet of vibration modes that are generally most significant in overall seismic responses. The effectiveness of the TSMD is verified by investigating the frequency response functions and seismic responses of one single-story and one 20-story two-way asymmetric-plan buildings.