Assessment of soil structure earthquake interaction induced soil liquefaction triggering

Download
2009
Unutmaz, Berna
Although there exist some consensus regarding seismic soil liquefaction assessment of free field soil sites, estimating the liquefaction triggering potential beneath building foundations still stays as a controversial and difficult issue. Assessing liquefaction triggering potential under building foundations requires the estimation of cyclic and static stress state of the soil medium. For the purpose of assessing the effects of the presence of a structure three-dimensional, finite difference-based total stress analyses were performed for generic soil, structure and earthquake combinations. A simplified procedure was proposed which would produce unbiased estimates of the representative and maximum soil-structure-earthquake-induced iv cyclic stress ratio (CSRSSEI) values, eliminating the need to perform 3-D dynamic response assessment of soil and structure systems for conventional projects. Consistent with the available literature, the descriptive (input) parameters of the proposed model were selected as soil-to-structure stiffness ratio, spectral acceleration ratio (SA/PGA) and aspect ratio of the building. The model coefficients were estimated through maximum likelihood methodology which was used to produce an unbiased match with the predictions of 3-D analyses and proposed simplified procedure. Although a satisfactory fit was achieved among the CSR estimations by numerical seismic response analysis results and the proposed simplified procedure, validation of the proposed simplified procedure further with available laboratory shaking table and centrifuge tests and well-documented field case histories was preferred. The proposed simplified procedure was shown to capture almost all of the behavioral trends and most of the amplitudes. As the concluding remark, contrary to general conclusions of Rollins and Seed (1990), and partially consistent with the observations of Finn and Yodengrakumar (1987), Liu and Dobry (1997) and Mylonakis and Gazetas, (2000), it is proven that soil-structure interaction does not always beneficially affect the liquefaction triggering potential of foundation soils and the proposed simplified model conveniently captures when it is critical.

Suggestions

An integrated seismic hazard framework for liquefaction triggering assessment of earthfill dams' foundation soils
Ünsal Oral, Sevinç; Çetin, Kemal Önder; Department of Civil Engineering (2009)
Within the confines of this study, seismic soil liquefaction triggering potential of a dam foundation is assessed within an integrated probabilistic seismic hazard assessment framework. More specifically, the scheme presented hereby directly integrates effective stress-based seismic soil liquefaction triggering assessment with seismic hazard analysis framework, supported by an illustrative case. The proposed methodology successively, i) processes the discrete stages of probabilistic seismic hazard workflow ...
Assessment of seismic soil liquefaction triggering beneath building foundation systems
Çetin, Kemal Önder; Jeremic, Boris (2012-12-01)
Although there exist some consensus on seismic soil liquefaction assessment of free field level soil sites, estimating liquefaction triggering potential beneath foundations still stays as a controversial and difficult issue. Assessing liquefaction triggering potential under mat foundations requires the estimation of cyclic and static stresses and the state of the soil medium. As part of these studies, conventionally used normalized cyclic demand term, cyclic stress ratio, is to be estimated addressing the s...
Assessment of structure-induced liquefaction triggering
Unutmaz, Berna; Çetin, Kemal Önder (2008-12-01)
Although there exists some consensus regarding seismic soil liquefaction triggering assessment of free field soil sites, assessing liquefaction triggering potential beneath building foundations still stays as a controversial and a difficult issue. Liquefaction triggering potential under building foundations is affected by both the static and cyclic stress state of the soil medium. As part of these studies, conventionally used normalized cyclic demand term, cyclic stress ratio corrected for Kα and K α effect...
Stabilization of expansive soils using waste marble dust
Başer, Onur; Çokça, Erdal; Department of Civil Engineering (2009)
Expansive soils occurring in arid and semi-arid climate regions of the world cause serious problems on civil engineering structures. Such soils swell when given an access to water and shrink when they dry out. Several attempts are being made to control the swell-shrink behavior of these soils. Soil stabilization using chemical admixtures is the oldest and most widespread method of ground improvement. In this study, waste limestone dust and waste dolomitic marble dust, by-products of marble industry, were us...
Seismic vulnerability, behavior and design of tunnel form building structures
Balkaya, C; Kalkan, E (Elsevier BV, 2004-12-01)
Multi-story reinforced concrete tunnel form buildings are one of the common structural types in regions prone to high seismic risk due to the buildings inherent earthquake resistance and ease of construction. Despite their good performance during earthquakes in 1999 in Turkey, and abundance of such structures scattered worldwide, current seismic codes and design provisions provide insufficient guidelines for their seismic design. As a compensatory measure, a series of modal and nonlinear static analyses are...
Citation Formats
B. Unutmaz, “Assessment of soil structure earthquake interaction induced soil liquefaction triggering,” Ph.D. - Doctoral Program, Middle East Technical University, 2009.