Dynamic Characteristics of Super High-Rise Residential Buildings in Kanto and Kansai Areas Based on Strong Motion Records during The 2011 Off The Pacific Coast of Tohoku Earthquake

Abstract

 This paper describes the dynamic response characteristics of 14 super high-rise residential buildings in the Kanto and Kansai areas on the basis of the recorded motions during the main shock of the 2011 off the Pacific coast of Tohoku Earthquake. In the Kanto area, the peak accelerations at the 1st floors or basements were around 100 cm/s². They were amplified by two to four times at the top floors. Structural responses in buildings constructed in the bayside area were greater than those in other areas because ground motions were amplified in the soil including soft surface layers. The building located in the Tokyo bayside area experienced the largest interstory drift angle of 1/170 rad. The natural frequencies gradually diminished as the structural response increased from its initial level. The natural frequency was reduced by about 20-40% by the time the relative displacement reached its peak and the reduced frequencies never recovered to their initial level. Bi-linear properties are inferred from the equivalent force-displacement relationship evaluated from the frequency ratio data.