Probabilistic methods for estimating the seismic deformations of underground structures

Download
index.pdf
2018
Soyman, Kadir Buğra
Show full item record
228
views
86
downloads
In seismic design of underground structures, simplified semi-deterministic methods based on the stiffness of the soil and the underground structure are used to estimate the seismic deformations. Generally, peak ground acceleration (PGA) value for different hazard levels are provided by the probabilistic seismic hazard assessment (PSHA) analysis, but a single (and deterministic) PGA value is employed in deformation calculations. The objective of this study is to propose a fully probabilistic framework for estimating the free field deformations (dff) of underground infrastructure, especially the metro stations. For this purpose, stations of two metro lines planned to be constructed in Istanbul are used as case studies. A new seismic source characterization model (SSC) is developed for the segments of North Anatolian Fault Zone that are close to metro stations. This SSC model is combined with current global and regionalized ground motion prediction models in PSHA framework to estimate the design ground motions. Simplified soil profiles of metro stations are developed and incorporated into 1-D equivalent linear (EQL) analysis. Using analysis results, two prediction models are developed for estimation of dff. According to performance-based earthquake engineering framework (PBEE), these models are incorporated into the hazard integral to provide annual rate of exceedance for specified dff levels and 475-year return period dff values are estimated for each station. Analysis results show that the 475-year return period dff values are significantly different than the dff values calculated by current semi-deterministic methods, indicating that fully probabilistic approach should be utilized in seismic design of underground structures.
Underground construction, Earthquake engineerin, Earthquake hazard analysis.
http://etd.lib.metu.edu.tr/upload/12622227/index.pdf
https://hdl.handle.net/11511/27426
Graduate School of Natural and Applied Sciences, Thesis

Suggestions

Probabilistic seismic hazard assessment for east anatolian fault zone using planar source models
Menekşe, Akın; Gülerce, Zeynep; Department of Civil Engineering (2015)
The objective of this study is to perform probabilistic seismic hazard assessment (PSHA) using planar seismic source characterization models for East Anatolian Fault Zone (EAFZ) and to update the design ground motions to be used in the region. Development of planar seismic source models requires the definition of source geometry in terms of fault length, fault width, fault plane angles and segmentation points for each segment and associating the observed seismicity with defined fault systems. This complicat...
A Semi-empirical method for estimation of maximum seismic shear strain in imperforated ground excited by vertically propagating shear waves
Dehghanian, Kaveh; Yılmaz, Mustafa Tolga; Department of Engineering Sciences (2016)
Seismic design of underground structures requires calculation of the deformation in surrounding geological formations. The seismic hazard on a site is usually expressed as a function of amplitude parameters of free-field motion. Therefore, simplified relations between depth and parameters of ground motion are necessary for preliminary designs. The objective of this study is to employ random vibration theory to develop a simple relationship between maximum shear strain (γmax), depth, and ground-motion intens...
Investigation of seismic isolation efficiency for building structures
Özdemir, Seda; Yakut, Ahmet; Ay, Bekir Özer; Department of Earthquake Studies (2016)
The main goal of this study is to assess the efficacy of seismic isolation for building type of structures with different structural systems, namely, dual systems and moment frame systems having also different number of floors. Specific to this study, the main parameters employed for efficacy assessment will be the interstorey drift ratio and floor acceleration since both structural and non-structural damage to be occured in a system are directly related to these two parameters. To assess the variations in inter...
Derivation of site-specific UHS based on simulated ground motions and its parametric effects on building fragility
Azari Sisi, Aida; Askan Gündoğan, Ayşegül; Department of Civil Engineering (2016)
Estimation of seismic demands is essential for the purpose of structural seismic design and analyses. It is significant to obtain reliable ground motion amplitudes to estimate seismic damage on structures in a realistic manner. The ground motion simulation methodologies provide a physical approach to estimate seismic demands in the regions with sparse recording data and scarce networks. This dissertation consists of two main parts: In the first part, site-specific uniform hazard spectrum (UHS) of Erzincan r...
Ground motion prediction equations based on simulated ground motions
Gür, Kader; Askan Gündoğan, Ayşegül; Kale, Özkan; Department of Earthquake Studies (2018)
Ground Motion Prediction Equations (GMPEs) are one of the key elements in seismic hazard assessment to estimate ground motion intensity measures by basically taking into account source, path and site effects. Most of the existing predictive models are derived from databases compiled from real (or observed) ground motion data. However, in data-poor regions, a novel practice to develop new GMPEs is to use simulated or hybrid ground motion datasets for performing reliable seismic hazard analysis. Simulations o...
Citation Formats
K. B. Soyman, “Probabilistic methods for estimating the seismic deformations of underground structures,” M.S. - Master of Science, Middle East Technical University, 2018.
METU IIS - Integrated Information Service open@metu.edu.tr