Comparative response and performance of base‐isolated and fixed‐base structures

Abstract

Summary A building with a seismic isolation system, in an earthquake, is recognized as producing substantially smaller accelerations and deformations compared with a building that use other systems. This type of system is therefore expected to better protect the building's nonstructural components, equipment, and other contents that are essential for the activities conducted in the building. Unlike many available studies on building responses, only a small number of studies on a buildings' nonstructural component responses are available, and no study has directly addressed building performance with regard to nonstructural component protection. This paper therefore measures the performance of various seismically isolated buildings. Specifically, the effects of important structural parameters, namely, isolation stiffness, isolation damping ratio, and number of stories on the response of base‐isolated structures are investigated parametrically. Ground motions with 2% exceedence in 50years Maximum Considered Earthquake (MCE) are used. Performance is compared with that of fixed‐base structures in order to present data that will be useful in justifying the more costly technology. The buildings are 3, 9, and 20 stories, represented by MDOF shear‐beam models. As examples of displacement‐sensitive and acceleration‐sensitive components, partition walls and ceilings are considered, respectively. The Pacific Earthquake Engineering Research Center performance‐based earthquake engineering methodology is adopted to evaluate the failure return periods of the examples based on their available fragility curves. In addition, the curves are varied hypothetically to understand the sensitivity of the return period to the curve features. Then, the median and dispersion of fragility curves required to satisfy the components' desired failure return period are obtained. Copyright © 2015 John Wiley & Sons, Ltd.

Effects of the improper modeling of viscous damping on the first‐mode and higher‐mode dominated responses of base‐isolated buildings

“…As an illustrative example, for the studied four-story frame, k 1 = 4.06×10 5 kN/m; θ 1 = 0.46 rad; and assuming a viscous damping ratio of 5%, β k = 7.2×10 −3 s. Substituting these parameters into Equation (15), C vd 1 is equal to 3.64×10 3 kN-s/m.…”

“…The horizontal component of the VD force should simulate the KD force given by Equation (13). Therefore, the λ exponent should be equal to unity, and the damping coefficient C vd i should satisfy Equation (15).…”

“…Many research works dealing with BI buildings (eg, [8][9][10][11][12][13][14] used the RD approach in which the multipliers of mass and stiffness matrices were computed based on the BI modes. Some other works adopted variants of the KD approach (eg, see [15][16][17] ).…”

Development of a tunable friction pendulum system for semi‐active control of building structures under earthquake ground motions

“…Mitigation of the seismic response of structures subjected to large earthquake ground motion is one of the major challenges in structural engineering . Over recent decades, the base isolation system has been shown to effectively protect structures and facilities against earthquakes . The friction pendulum system (FPS) isolator is a commonly used base isolation system .…”

“…1 Over recent decades, the base isolation system has been shown to effectively protect structures and facilities against earthquakes. 2,3 The friction pendulum system (FPS) isolator is a commonly used base isolation system. [4][5][6][7] A conventional FPS isolator primarily consists of a slider and a sliding surface, which is usually concave shaped.…”