Seismic Response Analysis and Optimum Design Of A Concave Ball Support İsolated System for A Three Story Concrete Structure

Kaplan, Halit
Dölen, Melik
This paper investigates the seismic response and optimum design of a base isolation system for earthquake protection of structures. The system incorporates spherical supports for the base, a specially designed spring-cam system to keep the base rigidly supported under normal conditions and to allow it to move for the duration of the earthquake under the constraint of a spring with optimized stiffness characteristics. A single degree of freedom structure was considered to investigate the feasibility of the concept. The simulation of the system response shows a 20 times reduction of the transmitted force as a result of using the proposed design in the considered case. This paper extends the previous study to the case a 3 story concrete structure subjected to the Taft as well as El Centro earthquakes. A 11.5 and 17 times reduction of the maximum transmitted force was achieved for the considered disturbances respectively without any adverse effects due to the tilting moment which is inherent in this type of base isolation. Since the system performance is highly dependent on the rapid unlocking of the cams in the event of a seismic disturbance, careful consideration should be given to the design of a reliable cam release control. This can be achieved by spring loading each cam such that it would be normally unlocked. A hydraulic actuator would be used to force it rotate to the locking position under fluid pressure which would be constantly maintained at the design level during normal conditions. The actuator would be equipped with a quick response release valve for rapidly releasing the pressure and consequently unlocking the cam as soon as an earthquake is detected.
Citation Formats
H. Kaplan and M. Dölen, “Seismic Response Analysis and Optimum Design Of A Concave Ball Support İsolated System for A Three Story Concrete Structure,” presented at the Technical Congress of Küçükçekmece and its Periphery, İstanbul, Turkey, 2003, Accessed: 00, 2021. [Online]. Available: