Seismic Behaviors of a Structure Isolated with Spherical Sliding Isolators

• Main Authors: Shi Hon Shi, 許宏旭
• Other Authors: Shuenn-Yih Chang
• Format: Others
• Language: zh-TW
• Published: 2003
• Online Access: http://ndltd.ncl.edu.tw/handle/90877060901937634088

碩士 === 國立臺北科技大學 === 土木與防災技術研究所 === 91 === In order to confirm the feasibility of seismic isolation of spherical sliding isolators (SSI), a 3-story steel frame with and without SSI connections was tested on the shaking table under moderate earthquake ground excitations. Whereas, for severe earthquake ground motions, only the steel frame with SSI connections was tested on the shaking table, while seismic responses for that without SSI connections were obtained from computer simulations by using SAP2000. This is intended to protect the steel frame from any damage since it will be tested into inelastic range under severe earthquake ground motions if there are no SSI connections to isolate the earthquake force. Eight ground acceleration records, which possess different frequency content, were selected as input data for the shaking table tests. This is proposed to thoroughly confirm that the seismic responses of the structures isolated with SSI connections are frequency independent. Furthermore, comparisons of the responses for the steel frame with and without SSI connections confirm the feasibility of SSI connections to effectively isolate the earthquake force. In fact, only a small part of earthquake force was transferred to upper part of the structure, which is above the SSI connections. Thus, the story drift is significantly reduced when compared to the original frame, which involves no SSI connections. On the other hand, it is also experimentally verified that the structure with SSI connections can automatically eliminate the adverse torsion effect. This is because that the restoring force of the SSI connection is directly proportional to the supported weight and it is indicated that the center of geometry of the activated SSI connections always coincides with the center of mass of the structure, and thus the torsion motion can be diminished.