Robustness of simplified analysis methods for rocking structures on compliant soil
Open access
Date
2020-11Type
- Journal Article
Abstract
Recognizing the beneficial effect of nonlinear soil-foundation response has led to a novel design concept, termed 'rocking isolation'. The analysis and design of such rocking structures require nonlinear dynamic time history analyses. Analyzing the entire soil-foundation-structure system is computationally demanding, impeding the application of rocking isolation in practice. Therefore, there is an urgent need to develop efficient simplified analysis methods. This paper assesses the robustness of two simplified analysis methods, using (i) a nonlinear and (ii) a bilinear rocking stiffness combined with linear viscous damping. The robustness of the simplified methods is assessed by (i) one-to-one comparison with a benchmark finite element (FE) analysis using a selection of ground motions and (ii) statistical comparison of probability distributions of response quantities, which characterize the time history response of rocking systems. A bridge pier (assumed rigid) supported on a square foundation, lying on a stiff clay stratum, is used as an illustrative example. Nonlinear dynamic FE time history analysis serves as a benchmark. Both methods yield reasonably accurate predictions of the maximum rotation theta(max). Their stochastic comparison with respect to the empirical cumulative distribution function of theta(max)reveals that the nonlinear and the bilinear methods are not biased. Thus, both can be used to estimate probabilities of exceeding a certain threshold value of theta.Developed in this paper, the bilinear method is much easier to calibrate than the nonlinear, offering similar performance. (© 2020 John Wiley & Sons). Show more
Permanent link
https://doi.org/10.3929/ethz-b-000424319Publication status
publishedExternal links
Journal / series
Earthquake Engineering & Structural DynamicsVolume
Pages / Article No.
Publisher
WileySubject
Rocking foundations; Rocking structures; Seismic isolation; Simplified analysis methodology; Soil–structure interactionOrganisational unit
02607 - Institut für Geotechnik / Institute for Geotechnical Engineering09569 - Anastasopoulos, Ioannis / Anastasopoulos, Ioannis
09663 - Vassiliou, Michalis / Vassiliou, Michalis
Funding
172512 - Overturning probability of uplifting structures under far-field earthquake excitation (SNF)
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