Energy based seismic assessment and design

Download
2019
Alıcı, Fırat Soner
The need to improve the reliability of current earthquake resistant design procedures has promoted energy-based concepts that employ seismic input energy and energy dissipation capacity of structures as the main design tools. Energy based approaches provide effective tools at both design and assessment stages for a comprehensive interpretation of the seismic behavior of structural systems during an earthquake excitation. Energy based assessment and design procedure includes two crucial aspects. The first one is the prediction of input energy spectra, considering both the structural and ground motion related parameters. The second concern is the evaluation of the actual energy absorption and dissipation capacity of structural systems during seismic response. In this regard, the aim of this study is first to introduce a procedure for the prediction of earthquake input energy spectra considering the effects of structural properties (damping ratio ξ and lateral strength ratio Rµ) and ground motion characteristics (moment magnitude Mw, soil type S, fault type F, distance to fault R). Furthermore, the effects of inelastic behavior and near-fault ground motions on input energy are also considered, and presented in this study. Then the energy dissipation characteristics of SDOF and MDOF systems are studied, respectively. In this sense, the relation between input energy and dissipated energy is obtained, and sensitivity of energy dissipation efficiency of SDOF systems is assessed. In this scope, two different Rµ–ξ–T spectra, as an improvement to equal displacement rule, are derived for estimating the maximum displacement of inelastic SDOF systems from the maximum displacement of equivalent linear SDOF systems. In the application stage, the predicted input energy and displacement spectra are integrated to attain the energy dissipation mechanisms of MDOF systems. Accordingly, it is aimed that a sufficient number of plastic hinges required to dissipate the imparted energy are detected from response spectrum analysis, by using the modal energy formulation of MDOF systems and estimated modal inelastic displacements. Thus, it is ensured that unlike the capacity design in which all beam-column connections are designated and designed as potential plastic hinge locations, a limited number of plastic hinges at the predefined locations can dissipate the imparted energy during seismic response efficiently. Based on the obtained results in this study, the suggested method improves the capacity based seismic design procedures in improving the seismic performance of structural systems.

Suggestions

Ground motion simulations based on regional input parameters and their impact on insurance premiums: Bursa case
Ünal, Barış; Askan Gündoğan, Ayşegül; Kestel, Sevtap Ayşe; Department of Earthquake Studies (2015)
Determination of earthquake parameters are required for earthquake resistant design and retrofitting of exsisting structures. There are not many options to obtain earthquake data for regions with no or sparce earthquake recordings. Even though some methods are aplicable to these regions they generate only peak ground motion parameters. For cases that require the full ground motion simulations are necessary. Simulations can also be used for gaining knowledge about source, path and site effects. In this study...
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...
Influence of seismic source and ground motion modeling on the probabilistic seismic hazard assessment of the city of Van after the 23 october 2011 mw7.2 earthquake
Şenyurt, Mehtap; Akkar, Sinan; Yılmaz, Mustafa Tolga; Department of Civil Engineering (2013)
Reliable assessment of seismic hazard is the most important step for seismic design and performance assessment of structural systems. However, the inherent uncertainty in earthquakes as well as modeling of ground motion may affect the hazard computed for a particular region. This study investigates the influence of seismic source and ground motion modeling on probabilistic seismic hazard assessment (PSHA). The study considers the seismicity around the city of Van to achieve its objective as this city was hi...
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...
Seismic Response Analysis and Optimum Design Of A Concave Ball Support İsolated System for A Three Story Concrete Structure
Kaplan, Halit; Dölen, Melik (2003-10-10)
This paper investigates the seismic response and optimum design of a base isolation system for earthquake protection of structures. The system incorporates spherical supports for the base, a specially designed spring-cam system to keep the base rigidly supported under normal conditions and to allow it to move for the duration of the earthquake under the constraint of a spring with optimized stiffness characteristics. A single degree of freedom structure was considered to investigate the feasibility of the c...
Citation Formats
F. S. Alıcı, “Energy based seismic assessment and design,” Ph.D. - Doctoral Program, Middle East Technical University, 2019.