Master Degree / Yüksek Lisans Tezleri
Permanent URI for this collectionhttps://hdl.handle.net/11147/3008
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Master Thesis Response of Vertically Loaded Energy Piles Under Earthquake Excitation(2023) İşbuğa, Volkan; İşbuğa, Volkan; 03.03. Department of Civil Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyPile foundations are deep foundation systems that are used to transfer loads from superstructure to soil by either resisting surface friction or reaching a deeper and stiffer soil layer when geotechnical properties of the soil site are not sufficient to carry the loads transferred from superstructure. Energy piles fulfill the same function along with the ground heat exchanging via heat pump systems, thus satisfying the energy demand of a building for heating-cooling operations. This feature of energy piles draws attention as an innovative system supplying a renewable energy resource. However, heat exchanging operations of energy piles cause temperature variations on pile and the surrounding soil which may cause additional load and deformations. Moreover, temperature variations may affect the elasticity modulus of soils and shear strength of cohesive soils. In this study, earthquake response of an axially energy loaded pile was investigated considering the heating effect under 2020 Izmir earthquake motion using finite element method and compared to the those of identical regular piles. We performed analyses with different soil types, geometric properties, and temperature magnitudes under steady-state heating. Based on the analysis results, heating effect on pile head stiffness with respect to geometric properties were obtained. Two important conclusions have been made; (i) the most critical effect on heating depends on mechanical loading condition of pile and thermal expansion coefficient of soil, (ii) geometric properties may affect the temperature distribution resulting in an unforeseen change in pile head stiffness.Master Thesis Effect of Column-Beam Moment Capacity Ratios on the Frame Plastic Failure Mechanism(01. Izmir Institute of Technology, 2023) Akhtari, Rohullah; Dönmez, Cemalettin; Dönmez, Cemalettin; 03.03. Department of Civil Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyThe strong-column weak-beam design ratio plays a crucial rule to design the structures particularly for high seismic region. Interestingly, the ratio to be used is still under spotlight for research. Observations and analytical studies have demonstrated that the ratio's effectiveness varies with some parameters. One of these parameters is the number of stories in a building. The failure mechanism of the structures depends on this ratio and the design ratio efficiency seems to change as building's stories increases. This efficiency also seem to saturate at a point depending on number of stories. In this study, three case studies have been assessed and analyzed. Each case study contains three reinforced concrete frames with different strong-column weak-beam design ratios that varies from 1.2 to 3.0. For each case study, the design ratios are ranged into three parts: (i) ratios between 1.2 to 1.5; (ii) ratios between 1.5 to 2.0; (iii) ratios between 2.0 to 3.0. The Turkish Earthquake Regulation (2018) has been utilized for the design procedures. The pushover and time-history analysis of frames were performed using OpenSees software framework (McKenna et al., 2010). Columns have been modeled with fiber sections and the beams have been modeled with concentrated rotational springs at the ends. Both members are accepted to be linear in between. The plastic hinge occurrence at the end of members were monitored to observe the frames' failure mechanism.Master Thesis Nonlinear Finite Element Analysis of Reinforced Concrete Structures Subjected To Impact Loads(Izmir Institute of Technology, 2010) Cağaloğlu, Neriman Çare; Saatcı, Selçuk; Saatcı, Selçuk; 03.03. Department of Civil Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyDesign of reinforced concrete structures against extreme loads, such as impact and blast loads, is increasingly gaining importance. However, due to the problem.s complicated nature, there exists no commonly accepted methodology or a design code for the analysis and design of such structures under impact loads. Therefore, engineers and researchers commonly resort to the numerical methods, such as the finite element method, and utilize different methods and techniques for the analysis and design. Although each method has its advantages and disadvantages, usually engineers and researchers persist on their method of choice, without evaluating the performance of other methods available. In addition, there is no significant study in the literature comparing the methods available that can guide the engineers and researchers working in the area. This study compares the performance of some numerical methods for the impact analysis and design with the help from actual impact test results in the literature. Computer programs VecTor2 and VecTor3 were selected for nonlinear finite element methodology, which were based on the Modified Compression Field Theory. Impact tests conducted on reinforced concrete beams were modeled and analyzed using these programs. Moreover, same beams were modeled also using a single degree of freedom spring system method. The results obtained from both approaches were compared with each other and the test results, considering their accuracy, computation time, and ease of use.