Robust Optimal Damper Placement of Nonlinear Oil Dampers With Uncertainty Using Critical Double Impulse

Abstract

A new robust method for optimal damper placement is presented for building structures under the critical double impulse. Oil dampers are treated here as representative supplemental dampers to control the seismic response of high-rise buildings. Such oil dampers usually obey a bi-linear force-velocity relation in controlling the maximum damping force through a relief mechanism to avoid the occurrence of excessive design forces in surrounding frames. The influence of uncertainty in characteristics of those bi-linear oil dampers on building structural safety is investigated. For the efficient evaluation of dynamic performance, the resonant critical double impulse is used as the base input instead of actual earthquake ground motions. Since the critical double impulse is determined to maximize the input energy to the objective building by changing the second impulse timing, uncertainties in input ground motions can be taken into account in a robust manner. To consider these various uncertainties, the robustness function based on the Info-Gap model is used in the robust optimization to assess structural performance variations caused by various uncertainties in the structural design phase. In this paper, a new innovative objective function in the robust optimal damper placement problem is proposed to enhance the robustness of structural performance under the variation of structural parameters by comparing the robustness function of the robust design with that of an ordinary optimal damper placement without considering uncertainties. Numerical examples of the robust optimal design of linear and bi-linear oil damper placements are shown for 10-story and 20-story planar building frame models. Structural performances of the robust optimal design to the conventional design earthquake ground motions are examined to investigate the validity of using the critical double impulse in the structural design under uncertainties.

Analysis and design of non-linear seismic isolation systems for building structures—An overview

“…Kangda and Bakre (2018) studied the seismic isolation of adjacent buildings, observing that at low damping ratio, non-linear dampers perform better than linear dampers in reducing absolute accelerations. The optimal placement of non-linear dampers for building structures was investigated by Fujita et al (2014Fujita et al ( , 2021, showing that the velocity exponent α plays a key role in vibration suppression under low level seismic input. Moreover, a non-linear damper is much more effective than a linear damper under very rare earthquakes having seismic intensities larger than the design earthquakes.…”

Robust optimal damper placement based on robustness index simultaneously considering variation of elastoplastic design criteria and input level

“…It is well-known that damper characteristics such as oil dampers may differ between actual and predetermined values due to various uncertainties such as temperature dependence, aging, and manufacturing errors. Fujita and Yasuda (2016) and Fujita et al (2021) developed robust optimal damper placement problems considering variations in the damping performance of linear and nonlinear oil dampers, but they do not consider building plasticity.…”

A Simple Critical Response Evaluation Method for Base-Isolation Building-Connection Hybrid System Under Double Impulse as Representative of Near-Fault Ground Motion

“…Since intrinsically uncertain characteristics of earthquake ground motions are inevitable, the reliable prediction of forthcoming events in regards to time, space, and character is extremely difficult (Takewaki, 2013;Takewaki et al, 2012;Takewaki et al, 2013). Although newer buildings systems such as passive control systems and base-isolation systems are anticipated as effective strategies for guaranteeing the structural safety of building structures, the structural properties of constituent members and elements of such innovative systems are not certain (Ben-Haim, 2006;Fujita et al, 2021). In Japan, the consideration of the variabilities of structural properties of isolators and dampers is mandatory in the design of passively controlled buildings and base-isolated buildings because the uncertainty degree (± 20-30%) of isolators and dampers is usually larger than those of building frame members (beams and columns) (Takewaki et al, 2012;Fujita et al, 2021).…”

“…Although newer buildings systems such as passive control systems and base-isolation systems are anticipated as effective strategies for guaranteeing the structural safety of building structures, the structural properties of constituent members and elements of such innovative systems are not certain (Ben-Haim, 2006;Fujita et al, 2021). In Japan, the consideration of the variabilities of structural properties of isolators and dampers is mandatory in the design of passively controlled buildings and base-isolated buildings because the uncertainty degree (± 20-30%) of isolators and dampers is usually larger than those of building frame members (beams and columns) (Takewaki et al, 2012;Fujita et al, 2021). The concept of robustness and redundancy plays a central role in the resilient seismicresistant design of such building structures (Ben-Haim, 2006;Takewaki et al, 2012;Fujita et al, 2021).…”

“…In Japan, the consideration of the variabilities of structural properties of isolators and dampers is mandatory in the design of passively controlled buildings and base-isolated buildings because the uncertainty degree (± 20-30%) of isolators and dampers is usually larger than those of building frame members (beams and columns) (Takewaki et al, 2012;Fujita et al, 2021). The concept of robustness and redundancy plays a central role in the resilient seismicresistant design of such building structures (Ben-Haim, 2006;Takewaki et al, 2012;Fujita et al, 2021). In the field of resilience, the theme of "Community Resilience" is receiving much interest recently because of the complexity of the concept of resilience and the difficulty in its realization in a real community consisting of many built environments (Mieler et al, 2015;Masoomi and van de Lindt, 2019;You et al, 2021).…”