Master Degree / Yüksek Lisans Tezleri
Permanent URI for this collectionhttps://hdl.handle.net/11147/3008
Browse
2 results
Search Results
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.