A Simple Response Evaluation Method for Base-Isolation Building-Connection Hybrid Structural System under Long-Period and Long-Duration Ground Motion

Abstract

An innovative hybrid control building system of base-isolation and building-connection has been proposed in the previous study. This system has two advantages, (i) to resist an impulsive earthquake input through the base-isolation system and (ii) to withstand a longduration earthquake input through the building-connection system. A simple response evaluation method without the need of non-linear time-history response analysis is proposed here for this hybrid building system under a long-period and long-duration ground motion. An analytical expression is derived in the plastic deformation of an elastic-perfectly plastic single-degree-of-freedom (SDOF) model with viscous damping under the multi-impulse, which is the representative of long-period and long-duration ground motions. A transformation procedure of a base-isolation building-connection hybrid structural system into an SDOF model is proposed by introducing two steps, one is the reduction of the main base-isolated building to an SDOF system, and the other is the reduction of the connecting oil dampers supported on a free-wall to an oil damper with a newly introduced compensation factor on a rigid wall. Application of the analytical expression of the plastic deformation to the reduced SDOF model including the compensation factor on the connecting oil dampers enables the development of a simplified, but rather accurate response evaluation method. The time-history response analysis of the multi-degree-of-freedom model and the comparison with the proposed simplified formula make clear the accuracy and reliability of the proposed simplified response evaluation method.

Smart Seismic Control System for High-Rise Buildings Using Large-Stroke Viscous Dampers Through Connection to Strong-Back Core Frame

“…This correction factor is introduced to account for various factors that could cause differences in damper behavior in the MDOF and SDOF models. A similar procedure was adopted in the reference (Hayashi et al, 2018). Let C d * (= βC d ) denote the corrected damping coefficient.…”

“…The most popular includes the interstory-type (Takewaki, 2009;Lagaros et al, 2012;Domenico et al, 2019) and soft first story-type (Tani et al, 2017). However, passive structural control systems, able to respond to both near-fault ground motions and long-duration/ long-period ground motions, are very limited (Murase et al, 2013;Takewaki, 2015, 2017;Hayashi et al, 2018). Structural control via passive control devices is difficult for near-fault ground motions because the earthquake energy input is made during very short time interval.…”

Semi-actively Implemented Non-linear Damping for Building Isolation Under Seismic Loadings

“…In laboratory studies, in order to investigate the performance of a building isolation system, the building system is often simplified to a mass-stiffness-damping MDOF system and then further scaled down to a 2-DOF system as shown in Figure 1 (Wang and Dyke, 2013;Amini et al, 2015;Hayashi et al, 2018;Ho et al, 2018), where the lower and upper masses represent the floor slab above the isolation layer and the superstructure of the target building, respectively. In Figure 1, m 1 and m 2 are the masses of the 2-DOF system, k 1 and k 2 are the stiffness parameters, c 1 and c 2 are damping parameters, x 1 and x 2 are the 1st and 2nd floor displacements relative to the ground motion z, respectively.…”

“…Building isolation systems are important for protecting buildings during earthquakes (Fujita et al, 2016;Hayashi et al, 2018). Traditional building isolation systems are designed using low horizontal-stiffness bearings to achieve low resonant frequencies so as to isolate earthquake loadings over a wide range of frequencies (Naeim, 1989).…”

Hysteretic-Viscous Hybrid Damper System With Stopper Mechanism for Tall Buildings Under Earthquake Ground Motions of Extremely Large Amplitude

“…However, after the experience of catastrophic damages due to unpredictable natural hazards, the design principle was partially changed to the use of passive control devices for continuous use of buildings without disruption. The wide range of research on passive control can be found across versatile literature (for example, Aiken et al, 1993;Hanson, 1993;Nakashima et al, 1996;Soong and Dargush, 1997;Hanson and Soong, 2001;Takewaki, 2009;Lagaros et al, 2013;Fukumoto and Takewaki, 2017;Tani et al, 2017;Hayashi et al, 2018;Makita et al, 2018;Kondo and Takewaki, 2019;Kawai et al, 2020). Even in such circumstances, another kind of difficulty arose in the 2016 Kumamoto earthquake (Japan).…”