Master Degree / Yüksek Lisans Tezleri

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Access type: Open accessSubject: search.filters.subject.Earthquake resistant design

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Now showing 1 - 7 of 7
  • Master Thesis
    Vulnerability assessment within the context of resilience To earthquake hazards: a case study of Bayraklı, İzmi̇r
    (01. Izmir Institute of Technology, 2024) Aydın, Helin; Kurt, Deniz Gerçek; 01. Izmir Institute of Technology
    Depremler, tüm doğal afetler arasında, Türkiye tarihinde en yıkıcı sonuçlara yol açmış olup, afet kaynaklı can kayıplarının çoğunluğu depremlerden kaynaklanmaktadır. Bayraklı, tarihi ve ekonomik öneminin yanı sıra, yüksek afet riski potansiyeline sahip ve deprem tehlikelerine karşı savunmasız yapı stokunun yoğun olduğu İzmir'in ilçelerinden biridir. Bu çalışma, ilçenin deprem tehlikelerine karşı kırılganlığı değerlendirmeyi amaçlamaktadır ve Bayraklı'nın tüm mahallelerini (24 mahalle) kapsayacak şekilde mahalle ölçeğinde uygulanmıştır. Çalışmada kırılganlık kriterlerini ölçmek ve deprem tehlikelerindeki önemlerini belirlemek için uzman görüşlerini değerlendirmek üzere Aanalitik Hiyerarşi Süreci yöntemi kullanılmıştır. Üç boyutu kapsayan kapsamlı bir kırılganlık değerlendirmesi yapılmıştır.: fiziksel kırılganlık, sosyal kırılganlık ve yapılı çevrenin kapasitesi. Uzman değerlendirmelerine dayanarak, kriterlerin deprem tehlikelerine karşı kırılganlık açısından göreceli önemi ortaya çıkarılmıştır. Kriter ağırlıklarına dayanarak, ArcGIS kullanılarak her ana boyut için kırılganlık haritaları oluşturulmuştur. Bu son aşamada sırasıyla Çay, Çiçek, Alpaslan, Tepekule Bayraklı ve Muhittin Erener, olmak üzere en kırılgan mahalleler belirlenmiştir. Bu araştırmanın bulguları, Bayraklı'nın deprem tehlikelerine karşı kırılganlığını azaltmayı amaçlayan kentsel planlama ve stratejik çabalar için değerli içgörüler sağlama potansiyeline sahiptir. Anahtar Kelimeler: Kırılganlık Değerlendirmesi, Afet Riski, Deprem Tehlikesi, Kapasite, Dayanıklılık, Analitik Hiyerarşi Süreci
  • Master Thesis
    Optimization of Isolators Between Floors of a High-Rise Building
    (01. Izmir Institute of Technology, 2024) Sönmez, Berkan; Turan, Gürsoy; Turan, Gürsoy; 03.03. Department of Civil Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
    Earthquake vibrations are natural phenomena that can cause tremors on the ground surface and lead to serious loss of life and property. Especially large-scale earthquakes have the potential to significantly damage infrastructure systems and the durability of structures. Several strategies are available to reduce these damages and increase the resistance of structures to earthquakes. One of these strategies is the implementation of seismic isolators. Seismic isolation minimizes earthquake damage to structures. The main purpose of the study is to examine the effectiveness of the seismic isolator being installed at various story levels of 3D 20-story steel building model. The building had two sets of 20 evaluation models, each with a different isolator story. The first set had identical evaluation models, except for the isolation story which is incremented in each model. The second set is similar to the first set except that the lower stories are strengthened by shear walls. The goal was to determine the best dimensions for the isolator to minimize the inter-story drift values. For this purpose, a set of 12 earthquake records are selected. These records are scaled according to the determined design spectrum. The optimization is performed for one of these earthquake records. Nonlinear dynamic analyses are carried out to evaluate the building model responses for all 12 earthquake records. Response values such as story shear forces and story drift ratios were analyzed and interpreted. This analysis will contribute to a better understanding of the impact of isolators with optimization methods on structural performance.
  • Master Thesis
    Earthquake Risk Management in Spatial Planning: the Case of Bayrakli-İzmir
    (2023) Akpınar, Figen; Akpınar, Figen; 02.03. Department of City and Regional Planning; 02. Faculty of Architecture; 01. Izmir Institute of Technology
    Turkey has a rapid urbanization and expansion, especially since 1950s. Today, 93.4 percent of the population live in urban areas (TurkSTAT 2022). This is a threat for the country because disasters that cause great damage to human life, building stock and urban infrastructure affect urban areas more negatively. Consequences of earthquake disasters have been experienced before because most of the country consists of earthquake-prone regions defined as high risk. That is why, the issue of reducing earthquake risks in spatial planning processes is of great importance for the country. Disaster mitigation strategies, policies, actions in planning decision making and implementation processes are currently crucial and cannot be postponed. 30 October 2020 earthquake caused more than 117 deaths, collapse of numerous buildings and massive damage in Bayraklı district of Izmir. The extent of the damage show that once again, the city has a high earthquake risk however it is not adequately prepared for that risk. This study aims to provide an overview of risk management in spatial planning, as well as providing guidance for future spatial planning methodologies, from the perspective of Izmir-Bayraklı's previous planning initiatives. After evaluating the earthquake risk management in spatial planning generally, the case of Bayraklı will be analysed in detail. This will include an analysis of the previous plans' risk management strategies, an explanation of why such significant destruction took place despite the existence of a nation-wide strict legal framework and planning efforts, and a recommendation for a spatial planning policy that will ensure the sound-basis risk management in planning. The case study area includes Mansuroğlu, Manavkuyu and Adalet neighbourhoods located in Bayraklı district of İzmir province.
  • Master Thesis
    Performance-Based Seismic Design of Reinforced Concrete Frame Buildings: a Direct Displacement-Based Approach
    (Izmir Institute of Technology, 2015) Karimzada, Nisar Ahmad; Aktaş, Engin; Aktaş, Engin; 03.03. Department of Civil Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
    Structures are designed using current seismic design codes which are mostly based on Force-Based Design approach. The initial aim of the current codes is the public safety. However, no clear information are provided regarding economic losses and business interruptions or downtime. Some information about damage states of structural components are provided, but very limited information is given for the damage states of non-structural members and content systems. Performance-Based Seismic Design (PBSD), which is a new concept in seismic design of structures, is a reliable approach capable of providing more detailed information on the performance levels of both structural and non-structural elements. Direct Displacement-Based Design (DDBD) approach, which is one of the available PBSD procedures, is implemented in this study. This approach has been utilized on four reinforced concrete irregular frames which are different in terms of number of stories. Story drift ratios were chosen as deformation limits to define the performance levels for specific earthquake hazard levels. DDBD approach in this study has been utilized in compliance with Turkish Seismic Design Code 2007. Furthermore, capacity design principles were adopted to make sure that plastic hinges occur in beams rather than in columns. After obtaining design internal forces (design moments, shear forces and axial forces), TS500 2003, is utilized to design members. Damage states for each member was determined, and non-linear pushover and time history analysis were carried out using SAP2000 v17.10 to check if story drift ratios meet the ones chosen. The base shear forces and the top displacements, in addition, for each frame were also checked with the ones obtained through DDBD approach.
  • Master Thesis
    Seismic Behavior of Steel I-Beams Modified by a Welded Haunch and Reinforced With Glass Fiber Reinforced Polymers
    (Izmir Institute of Technology, 2009) Özdemir, Timur; Eğilmez, Oğuz Özgür; Eğilmez, Oğuz Özgür; 03.03. Department of Civil Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
    Flange and web local buckling in beam plastic hinge regions of welded steel moment frames (SMF) can prevent beam-column connections to achieve adequate plastic rotations under earthquake-induced forces. As the use of fiber reinforced polymers (FRP) have increased in strengthening and repair of steel members in recent years, using FRPs in stabilizing local instabilities have also attracted attention. Generally, high modulus carbon FRP (CFRP) laminates, with elastic modulus similar to that of steel, are preferred in strengthening applications. On the other hand, glass FRP (GFRP) has a much smaller modulus than that of steel, typically one order of magnitude less, which limits its use in strengthening applications. However, this modulus mismatch is an asset when the primary goal is to stabilize inelastic local buckling with the least possible strength increase in the section. In a steel-GFRP hybrid system, while the low modulus of GFRP will not allow a significant strength increase in the beam, the flexural strength of GFRP can provide bracing to the underlying steel, which is flowing plastically. In this research study, the cyclic behavior of steel beams modified by a triangular haunch welded to the beam bottom flange only and reinforced with GFRP laminates at beam flanges have been investigated by finite element analysis (FEA). Cantilever I-sections with flange-web slenderness ratios higher then those stipulated in current seismic design specifications are analyzed under reversed cyclic loading. Both bare beam sections and sections reinforced with GFRP are investigated. The effects of GFRP thickness, width, and length on stabilizing local buckling are investigated. The flexural resistance of the beams at column face, interlaminar shear stresses in GFRP strips, and shear stresses at beam-GFRP binding surface are examined. The results reveal that the plastic rotation capacity of steel beams can be enhanced by the use of GFRP strips.
  • Master Thesis
    Seismic Behavior of Steel I-Beams Reinfor Ced With Glass Fiber Reinforced Polymer: an Experimental Study
    (Izmir Institute of Technology, 2010) Yormaz, Doruk; Eğilmez, Oğuz Özgür; Eğilmez, Oğuz Özgür; 03.03. Department of Civil Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
    Design guidelines, which are put into effect in the aftermath of the 1994 Northridge earthquake, require intermediate and special moment frames (IMF and SMF) be capable of maintaining 0.02 and 0.04 radians interstory drift, respectively without significant strength degradation and development of instability. However, local buckles in the plastic hinge region are major hindrances for the ductility capability and stability of the structural system. Thus, the research program aims to mitigate such inelastic instabilities by using glass fiber reinforced polymer (GFRP), which possesses elastic modulus roughly one order of magnitude less than that of steel. On the other hand, this elastic modulus discrepancy between GFRP and steel can be useful for stabilizing local buckles by means of the bracing effect of GFRP during plastic hinge formations. This thesis describes large-scale experimental study of the research program that investigates the seismic behavior of steel I-beams reinforced with GFRP. In this experimental study, four HE400AA beams with welded haunch (WH) modification and three HE500AA beams with no modification were tested under cyclic loading. The results of experimental study indicate that it does not seem possible to rely on GFRP reinforcement to increase the flexural resistance of connections at a rotation of 0.04 radians because the adhesive layer between steel and GFRP fails in rotations much lower than 0.04 radians. However, the seismic performance of the structure can be moderately improved with the bottom flange WH and GFRP reinforcement in order to maintain rotations without local buckles in accordance with the rotation demand of IMFs, which is 0.02 radians.
  • Master Thesis
    Investigation of the Benefits of Variable Orifice Dampers Used in an Earthquake Excited Three Story Structure
    (Izmir Institute of Technology, 2009) Gökdağ, Hakan; Turan, Gürsoy; Turan, Gürsoy; 03.03. Department of Civil Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
    Research in the field of control of civil engineering structures is a continuing process. The three basic approaches to structural control may be defined as follows passive control systems,active control systems and semi-active control systems. These systems have received much attention recently because they have versatility and adaptability of active control systems. Although there is a wide variety of these energy absorbing devices, but all have one thing in common . they absorb energy from the structure.Semi-active control systems possess the advantages of both active and passive control systems. Variable orifice dampers are semi-active control devices that utilize the hydraulic fluid flow to generate controllable damping forces. Depending on the state of the structure, the energy absorbing property of the variable orifice dampers is changed on the fly. In this study, the proposed semi-active control algorithm and the effect of variable orifice damper for seismic response reduction is examined. To demonstrate the efficiency of the proposed semi-active control algorithm and the usefulness of variable orifice dampers,controlled and uncontrolled behaviour of the three story model structure subjected to earthquake forces are investigated numerically. The three story model structure in Civil Engineering Laboratory in .YTE is utilized for numerical simulations. The results indicate numerically that the proposed semi-active control algorithm with a variable orifice damper can be used effectively to reduce the earthquake induced structural vibrations.