Structural Modeling and Dynamic Analysis of a Nuclear Reactor Building

Increasing energy demand urge the developing countries to consider different types of energy sources. Owing the fact that the energy production capacity of renewable energy sources is lower than a nuclear power plant, developed countries like US, France, Japan, Russia and China lead to construct nuclear power plants. These countries compensate 80% of their energy need from nuclear power plants. Further, they periodically conduct tests in order to assess the safety of the existing nuclear power plants by applying impact type loads to the structures. In this study, a sample third-generation nuclear reactor building has been selected to assess its seismic behavior and to observe the crack propagations of the prestressed outer containment. First, a 3D model has been set up using ABAQUS finite element program. Afterwards, modal analysis is conducted to determine the mode shapes. Nonlinear dynamic time history analyses are then followed using an artificial strong ground motion which is compatible with the mean design spectrum of the previously selected ground motions that are scaled to Eurocode 8 Soil type B design spectrum. Results of the conducted nonlinear dynamic analyses are considered in terms of stress distributions and crack propagations

Case study on seismic behavior of aseismically designed reinforced concrete frame structures

Gökçe Tönük (MEF Author)In this study, the seismic performances of two aseismically designed plan-irregular reinforced concrete frame (RCF) households damaged during the October 23, 2011 Van earthquake are assessed. Since no strong ground motion recordings from the main shock were available, first, strong ground motion parameters of the event are evaluated and then compatible with these parameters suits of real records are selected and scaled to match with the event's simulated acceleration spectrum to be used in the analytical investigations. The results of previous reconnaissance studies, in which one of the present authors was involved, are then discussed. Capacities of the considered RCF's are determined applying a 3D single-run adaptive pushover procedure that is capable of considering the effect of plan irregularities. The performance assessment procedure based on the current 2007 Turkish Earthquake Code is then applied to these investigated buildings. Additionally, nonlinear dynamic time history analyses are carried out using the previously selected time histories. The hysteretic behavior of the considered buildings is examined as the consequence of the conducted analyses and considering the different suits of selected ground motions, the seismic response of the buildings is evaluated in terms of interstorey drifts. None of the buildings are found to satisfy the expected performance level. Moreover, the numerical results are found to have good correlation with the field observation results.WOS:000434706200020Scopus - Affiliation ID: 60105072Science Citation Index ExpandedQ2ArticleUluslararası işbirliği ile yapılmayan - HAYIRTemmuz2018YÖK - 2017-1

Seismic behavior of irregular reinforced-concrete structures under multiple earthquake excitations

Reconnaissance studies on the recent Tohoku earthquake have reported collapse of structures due to multiple earthquake excitations in the earthquake-affected region. Strength and stiffness degradation is shown to be the primary reason for the observed damage. The present study aims to investigate the degrading behavior of irregularly built reinforced concrete structures subjected to the Tohoku ground motion sequences. Three-dimensional numerical models of three irregular reinforced concrete structures are developed. The structural characteristics of these buildings are then altered to achieve a regular case. The models contain appropriate damage features that can capture both the irregularity and material deterioration effects. The capacities of both cases are evaluated using the N2 and extended N2 procedures. The degrading models are then used for ground motion sequences measured at 23 selected stations. The results indicate that multiple earthquake effects are significant, and irregularity effects increase the dispersed damage under these excitation sequences