Master Degree / Yüksek Lisans Tezleri
Permanent URI for this collectionhttps://hdl.handle.net/11147/3008
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Master Thesis Structural Design of Rc Structures From Sustainable Development Perspective(01. Izmir Institute of Technology, 2023) Gültepe, Ekin; Dönmez, Cemalettin; Dönmez, Cemalettin; 03.03. Department of Civil Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyThe growth of the population and changing demands have become a significant problem due to the limited resources of the earth. Climate change has increased the occurrence of natural events and probable disasters due to insufficient infrastructure. The economic, environmental, and social aspects of the problem necessitate sustainable practices. On the other hand, probable disaster dictates design decisions to keep the physical environment intact and resilient. Hence, the expectations from the construction industry are high. The industry also needs to tackle the task of lowering the existing high consumption levels of natural resources and energy. Being resilient under seismic events is paramount for the areas that have high seismicity. The general trend of using less material for sustainability purposes conflicts with the resilient seismic design decisions which typically cause an increase in the initial consumptions. The studies on resilience and sustainability hint that there might be design opportunities that serve both purposes together. In this study, such an opportunity for RC residential buildings is focused. The resilience and energy cost of a conventional moment-resisting frame and the same frame with increased robustness through the addition of shear walls are studied. It is presumed in addition to the increased robustness, the thermal impact of the additional concrete mass will create an advantage for energy consumption in the life cycle of the building. The design decision for shear walls is based on the proposal by Hassan and Sozen (1997). Nonlinear time history analysis is performed for both frames according to Turkish Earthquake Regulation. Results show that the robust frame has the needed resilience. The energy analysis shows that the frame with shear walls has significantly higher consumption initially. However, when the thermal impact of the concrete is included in the full life cycle, the energy consumption difference reduces from 18% to 4%. As a result, it could be stated that providing sufficient robustness to the structure by shear walls at targeted locations provides an opportunity to have a resilient and sustainable structure with a minor increase in total energy cost throughout the life cycle of the structure.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 Evaluation of Effective Stiffness Procedures in Seismic Design of Reinforced Concrete Frames(01. Izmir Institute of Technology, 2021) Dönmez, Cemalettin; Dönmez, Cemalettin; 03.03. Department of Civil Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyThis study investigates the success of the effective stiffness procedures defined for the design of reinforced concrete frames in seismic design regulations. The emphasis will be on the effort to model success relations. The origins of the effective stiffness approach could be identified in the effort to use the equal displacement rule for seismic design purposes. The equal displacement rules dictate that if a system's effective stiffness at the sustained drift levels could be identified, the linear and nonlinear system deflection demands are approximately equal. The nonlinear displacement response of a system could be obtained using this "estimated" stiffness value at the sustained displacement levels from the elastic analysis of the system. Hence, there is no consensus about defining the effective stiffness, and different approaches exist for its calculation. In this study, the effective stiffness approaches of the Turkish Earthquake Code (2018), Canadian Standards Association Design of Concrete Structures (CSA A.23.3-14), New Zealand Concrete Structures Standard (NZS3101-2006), Eurocode 8 (EN 1998-3), Building Code Requirement for Structural Concrete of American Concrete Institute (ACI318-19) and Sozen's Method are investigated in terms of effort in their execution to the success of the result. In order to provide a comparison in reference to measured values, the evaluation is based on the shaking table tests of a ten-story-three-bay reinforced concrete frame model. The numerical analysis is performed using the OpenSees platform. The model is formed by defining nonlinear rotational springs at the element ends. The effective stiffness definitions are performed per each regulation, and the results are compared with the test results. Also, a suite of ground motions is selected, and time history analyses are performed using each effective stiffness approach. Results are compared in terms of the maximum and envelope drift levels of the frames obtained by each approach.Master Thesis Seismic Analysis of an Ancient Lighthouse by Meso-Scale Modeling Technique(01. Izmir Institute of Technology, 2020) Gözün, Safiyullah Üveys; Dönmez, Cemalettin; Özdemir, İzzet; Özdemir, İzzet; Dönmez, Cemalettin; 03.03. Department of Civil Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyModeling masonry structures has always been a difficult subject due to the lack of information about the behavior, the heterogeneity of the masonry materials and complex geometries of masonry structures. In terms of the computational costs and complexity, several methods are proposed in the literature. In this thesis, the capabilities of the meso-scale modeling technique are investigated by means of two experiments selected from the literature and the seismic response of an ancient lighthouse. Brick and mortar type structure is idealized as expanded units surrounded by zero thickness cohesive interfaces representing the mortar behavior. This means that the failure of mortar layers is considered explicitly by means of cohesive surfaces whereas the mechanical response of expanded units is described by Drucker-Prager/Cap model. This approach is used to simulate the in-plane and the outof-plane behavior of masonry walls reported in the literature. After validating the models with the experimental results, implicit-dynamic time history analyses of an ancient lighthouse are conducted by using 2 different earthquake records. The influence of mortar properties on the energy dissipation mechanisms and collapse pattern of the structure are investigated by means of a parametric study. As an attempt to identify the critical earthquake level corresponding to the initiation of sliding within the lighthouse, a set of additional analyses are conducted with scaled earthquake records.