Master Degree / Yüksek Lisans Tezleri

Permanent URI for this collectionhttps://hdl.handle.net/11147/3008

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Subject: search.filters.subject.Reinforced concrete

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Now showing 1 - 5 of 5
  • 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 Technology
    This 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
    Punching Behavior of Hybrid Fiber Reinforced Concrete Panels
    (01. Izmir Institute of Technology, 2020) Naseri, Jamalullah; Saatcı, Selçuk; Saatçi, Selçuk; 03.03. Department of Civil Engineering; 01. Izmir Institute of Technology; 03. Faculty of Engineering
    Hybrid fiber reinforced concrete (HyFRC) is a more recent type of fiber reinforced concrete (FRC), which includes two or more different fibers types. HyFRC may result in a multifunctional material due to synergetic effects of the various type of fibers added in the mixture. In this study, punching behavior of HyFRC thin panels using three different types of steel fibers and polyvinyl alcohol (PVA) fibers were experimentally investigated. In total 13 panel specimens were cast with dimensions of 1700 x 1700 mm2 and thickness of 50 mm. The specimens were simply supported along the edges and loaded through a 150 mm circular steel plate at the center by a displacement-controlled hydraulic actuator. A load cell and fifteen displacement transducers were used to measure the applied load and vertical deflection of the specimens, respectively. All specimens that contained only steel fibers failed under punching. In hybrid fiber reinforced specimens with steel and PVA fibers, either a flexural failure or a punching failure followed by significant flexural deformations were observed. Test results confirm that fiber reinforced concrete has a very significant effect on thin panel's punching strength and displacement capacity. It was seen that hybridization of two different types of fiber, steel and PVA fibers, brings advantages in terms of punching load capacity, deformation characteristics and failure mode.
  • Master Thesis
    Mechanical Behavior of Hybrid Fiber Reinforces Concrete Under Direct Tension
    (Izmir Institute of Technology, 2020) Çetin, Fatma Şirin; Saatcı, Selçuk; Erdem, Tahir Kemal; Saatçi, Selçuk; Erdem, Tahir Kemal; 03.03. Department of Civil Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
    Using different fiber types together, called hybrid fiber reinforced concrete, may cause a mutual synergic response between fiber matrixes. Due to these synergic effects of different fiber combinations, the mechanical behavior of concrete may perform differently than single fiber reinforced concrete. In this study, the effects of fiber hybridization in the direct tension behavior of concrete mixtures obtained by using three different types of steel fiber and polyvinyl alcohol (PVA) fiber were investigated. In this scope, total of 50 dog bone shaped, notched specimens were cast for 10 different mixtures and tested under direct tension. Average tensile stress-crack width responses of concrete specimens were investigated. It was found that the addition of PVA fiber to 35 mm long single hook end and 60 mm long double hook end steel fiber mixtures with a volume ratio of 0.75% did not considerably change the tensile behavior post cracking. As a result of adding PVA fibers to 60 mm single hook steel fiber mixtures with a volume ratio of 1.25%, cracking stresses were decreased and post cracking behavior was adversely affected. Addition of PVA fibers to 60 mm single hook steel fiber mixture with 0.75% volumetric ratio was found to increase post cracking stress levels.
  • Master Thesis
    Effects of Shear Reinforcement on the Impact Behavior of Reinforced Concrete Slabs
    (Izmir Institute of Technology, 2014) Arsan, Yonca; Saatci, Selçuk; 01. Izmir Institute of Technology
    Design of reinforced concrete (RC) members against impact loads is required for many structures such as industrial facilities, military protective structures, and infrastructures. This study presents experimental investigation for strengthening RC slabs under impact loads using shear reinforcement. Slabs were strengthened against punching shear with two methods: using shear studs as shear reinforcement and using steel fiber reinforced concrete (SFRC) instead of plain concrete. Eight RC slabs with dimensions of 2150x2150x150 mm were tested. Four of the specimens, two identical pairs, were cast with shear studs around the point of impact. Remaining four specimens, again two identical pairs, were cast with 1% steel fibers. Pairs in each group contained two different levels of longitudinal reinforcement. For each pair, one specimen was tested under static loading, whereas its identical twin was tested under impact loads. Specimens were tested with a test setup that provides simply supported conditions. Support loads, displacements, accelerations, and strains on bars were measured during the tests. The study revealed that using shear studs and SFRC prevents brittle punching shear failure for both static and impact loading. Specimens with steel fibers reached the highest load carrying capacity for static test while specimens with shear reinforcement carried a smaller load for large deformations. Specimens with SFRC displayed a close to static behavior under impact loading, influenced only slightly by inertial forces due to impact. Specimens with shear studs were largely influenced by inertial forces and scabbing occurred at some areas. Specimens with steel fibers endured more impacts compared to control specimens and specimens with shear studs due to their higher energy dissipating capabilities.
  • Master Thesis
    Dynamic Behavior of Reinfor Ced Concrete Frames With Infill Walls
    (Izmir Institute of Technology, 2011) Çankaya, Mehmet Alper; Dönmez, Cemalettin; Dönmez, Cemalettin; 03.03. Department of Civil Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
    Current practices utilize infill walls as insulation or partition material but not as a structural material. The main reason for this choice is the complexity of the partition wall-frame interaction behavior. Therefore infill walls typically ignored in the structural designs. However, existence of partition walls heavily effect stiffness, strength and behavior of structures. The main purpose of the presented study is the investigation of the dynamic parameters of reinforced concrete frames with and without infill walls. Moreover, lateral strength, stiffness and energy dissipation properties of the frames are also studied. In order to achieve the purpose four planar, one-bay, four story RC frames with 1/5 scale are designed, constructed and tested. In the frames main parameters are selected as presence of partition walls and ductile/non-ductile reinforcement detailing. Experiments are consisted of static and dynamic tests. In static tests each frame subjected to lateral loads that were applied at the each story level to provide a lateral loading increasing with height. Lateral load levels were controlled by the drift levels in the first story. Dynamic tests were performed at the end of each deformation level and modal analysis methods are utilized. Analyses have shown that existence of partition walls in the frame increased the natural frequencies of the frames. However, reinforcement detailing did not have a significant effect on natural frequencies. It is also observed that the natural frequencies of the frames decreased with increasing damage level. On the other hand, presence of partition walls effected the damaged behavior of the frames and drift is observed to concentrate to the first story with the increasing level of damage. And finally stiffness, strength and energy dissipation properties of frames with partition walls are observed to be dramatically higher than the frames without partition walls.