Robustness Evaluation of Base-Isolation Building-Connection Hybrid Controlled Building Structures Considering Uncertainties in Deep Ground

Abstract

An evaluation method of robustness of base-isolation building-connection hybrid controlled building structures is developed by introducing a measure for robustness (robustness function) and considering shallow and deep ground uncertainties. The earthquake ground-motion amplitude at the earthquake bedrock is evaluated by the Boore's stochastic method including the fault rupture and the wave propagation into the earthquake bedrock. Then, the phase angle property at the earthquake bedrock is investigated by introducing the concept of phase difference, which is defined for each earthquake type. The ground-motion amplification in the shallow and deep ground is expressed by the one-dimensional wave propagation theory. The robustness of base-isolation buildingconnection hybrid controlled building structures is measured by use of the robustness function due to Ben-Haim (2006) and is evaluated by taking full advantage of the updatedreference-point method. It is shown that, as the total quantity of damping coefficients of connection dampers increases, the robustness for the deformation of the baseisolation story becomes larger without the drastic reduction of the robustness for the top acceleration.

Critical Ground Motion for Resilient Building Design Considering Uncertainty of Fault Rupture Slip

“…The lower one in Figure 4 illustrates the pseudo velocity response spectrum. The numbers 1, 2, 3 in figure legend indicate the difference of uniform random numbers for phase angles in Hisada (Kato et al, 2011) and the difference of Gaussian random numbers for phase difference (Equation 15) in Makita et al (2018). It can be observed from these figures that, while the acceleration time histories exhibit somewhat different properties, especially in its envelope, the pseudo velocity response spectra of both approaches correspond fairly well.…”

“…In a previous research by the authors (Makita et al, 2018), a point-source model of the fault rupture was assumed and the fault rupture process could not be taken into account. In this paper, the stochastic Green's function method based on a planesource model of the fault rupture is introduced.…”

“…FIGURE 1 | Slip function D(t) and slip correction function f(t), (A) Conventional ones, (B) Revised ones by Irikura (1986). This relation refers to inland earthquakes (Makita et al, 2018). In this paper, the near-fault ground motion is assumed in which the effect of the rupture directivity is small.…”

“…Okada et al (2016) proposed a new interval analysis technique for a soil-pile-structure interaction model by taking into account the uncertainty in soil properties. Makita et al (2018) considered a base-isolation, building-connection hybrid structural system (Murase et al, 2013(Murase et al, , 2014Kasagi et al, 2016;Fukumoto and Takewaki, 2017) and took into account the uncertainty in the site amplification. They treated the fault as a point source.…”

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The process of theoretical ground motion generation consists of (i) the fault rupture process, (ii) the wave propagation from the fault to the earthquake bedrock, (iii) the site amplification. The uncertainty in the site amplification was taken into account in the previous research (Makita et al, 2018). On the other hand, the uncertainty in the fault rupture slip (slip distribution and rupture front) is dealt with in the present paper.

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