Browsing by Author "İlki, Alper"

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Numerical Seismic Performance Investigation of Aac Infill Walls With Flat-Truss Bed-Joint Reinforcement
(National Technical University of Athens, 2023) İlki, Alper; Halıcı, Ömer Faruk
Autoclaved Aerated Concrete (AAC) is a lightweight, energy-efficient and easy-to-transport material. As a result, AAC walls are becoming increasingly common as an infill solution in earthquake-prone areas such as Turkey, Italy, and Greece. Although infills are considered as secondary components in seismic design, they are extremely vulnerable to damage during earthquakes along both in-plane (IP) and out-of-plane (OOP) directions. Previous post-earthquake site examinations revealed that the failure of infill walls can result in serious injuries and casualties. Furthermore, huge economic losses as well as disruption in the functionality of essential buildings that are supposed to be operational after earthquakes may adversely affect the daily life in the earthquake-affected regions. One of the potential methods for increasing the seismic resilience of infill walls is use of bed-joint reinforcement between infill courses. In this paper, the general approaches in the establishment of the numerical finite element model for infill walls with and without bed-joint reinforcement are presented. The developed model was evaluated according to the previous full-scale experimental test results from strength and damage propagation point of view. The model will be used to investigate the response of infills with various bed-joint reinforcement amounts and height-to-length ratios to generalize the seismic performance improvements obtained by the use of flat-truss reinforcement both in the IP and OOP directions.
Citation - WoS: 10
Citation - Scopus: 15
Out-Of Seismic Performance of Bed-Joint Reinforced Autoclaved Aerated Concrete (aac) Infill Walls Damaged Under Cyclic In-Plane Displacement Reversals
(Elsevier Sci Ltd, 2023) İlki, Alper; Demir, Uğur; Halıcı, Ömer Faruk; Zabbar, Yassin
The infill walls made of Autoclaved Aerated Concrete (AAC), which is a lightweight, fire resistant and energy efficient material, provide effective insulation solutions for building types of structures and becoming more and more popular in earthquake prone regions. Although the number of experimental tests examining the seismic response of clay brick infills is extensive, the amount of prior research on infill walls built of AAC blocks is rather limited. Past research revealed that the use of bed-joint reinforcement is one of the promising solutions to improve the global seismic response of masonry walls by enhancing strength and displacement capacity. In this study, the out-of-plane (OOP) seismic performance of AAC infill walls with flat-truss and innovative cord-type bed-joint reinforcement is experimentally evaluated. Also, consideration is given to the prior in-plane (IP) damage, which was found to degrade the seismic performance of infills in OOP direction. For this purpose, three IP and four OOP, in total, seven experimental tests were performed on four full-scale AAC infill wall specimens. The test parameters were selected in such a way as to make it possible to parametrically compare the OOP performance of AAC infills with flat-truss and cord-type bed-joint reinforcements with unreinforced AAC infill walls, together with the effect of prior IP damage on the OOP response of unreinforced AAC infill walls. It was found that the use of innovative cord-type bed-joint reinforcement improved the OOP strength to a similar extent to what was obtained from the truss-type reinforced specimen. In terms of ultimate displacement and energy dissipation capacity enhancement, the specimen with cord-type reinforcement performed better. In addition, the damages formed due to IP cyclic displacement reversals up to 0.005 drift ratio, which is defined as the drift limit for buildings with brittle infill walls in certain design codes, resulted in a significant reduction in the OOP strength and stiffness properties of AAC infills. The theoretical OOP strength calculations were found to provide unconservative strength values for the IP-damaged specimens.
Citation - WoS: 36
Citation - Scopus: 48
Cyclic and Monotonic Compression Behavior of Cfrp-Jacketed Damaged Noncircular Concrete Prisms
(2016) İlki, Alper; Dalgıç, Korhan Deniz; İspir, Medine
This paper focuses on rehabilitation/strengthening of damaged concrete prisms through external carbon-fiber-reinforced polymer (CFRP) jacketing. In order to evaluate the efficiency of the strengthening method on the damaged concrete prisms, an experimental study including 22 concrete prisms with square and rectangular cross sections was carried out. The parameters of the experimental study are the damage levels. Furthermore, effects of loading scheme (monotonic or cyclic) and cross section type (square and rectangular) were investigated in the existence of damage. The concrete prisms were tested under compression stresses up to three specified axial deformation levels to be representative of slight, moderate, and severe compression damages before strengthening. Tests were repeated after rehabilitation/strengthening of damaged specimens with CFRP jacketing. Test results showed that CFRP rehabilitation/strengthening was effective on enhancement of strength and deformability of the damaged concrete prisms. However, the efficiency of the strengthening method in terms of compressive strength tended to reduce when the level of damage increased. Furthermore, an available model is modified to include the effects of damage level, and the modified model is shown to produce accurate results. (C) 2015 American Society of Civil Engineers.
Citation - WoS: 6
Citation - Scopus: 6
Evaluation of Diaphragm Conditions in Aac Floor Structureswith Rc Beams
(2018) İlki, Alper; Uğurlu, Koray; Demir, Cem; Comert, Mustafa; Halıcı, Ömer Faruk
Diaphragm action in floor structures is an important aspect that affects both local behaviors of individual members and consequently, the global response of a structure. The diaphragm action of a built structure, therefore needs to be compatible with the assumed diaphragm condition in the design phase to prevent unpredicted overloading of load bearing members in a seismic action. Autoclaved aerated concrete (AAC) is a cost-effective, lightweight and energy efficient material, and its usage as a construction material has rapidly increased in recent decades. However, there is a limited experience regarding the in-plane behavior of the floor structures made of AAC panels in terms of diaphragm action. In this paper, the in-plane response of AAC floors is experimentally investigated and the floor performance of a typical building is analytically investigated according to ASCE 7-16 (ASCE/SEI in Minimum design loads for buildings and other structures, The American Society of Civil Engineers, Reston, 2016). Full-scale experiments carried out through loading AAC floors in lateral directions to the panels, either parallel or perpendicular, provided important information about the damage progress and overall performance of such floors. A number of finite element modeling techniques that are generally used for modeling of AAC floors were examined and then validated through comparisons with test results. Finally, the diaphragm condition of a three-story building made of AAC walls and floor panels was assessed. The results indicated that the AAC floors in the examined building can be idealized as rigid diaphragms according to ASCE 7-16.
Structural Assessment of the 13th Century Great Mosque and Hospital of Divrigi: a World Heritage Listed Structure
(12th International Conference on Structural Analysis of Historical Constructions (SAHC 2021), 2021) İlki, Alper; Berlucchi, Nicola; Demir, Cem; Şanver, Ali Naki; Hurata, Ali; Cömert, Mustafa; Halıcı, Ömer Faruk
The Great Mosque and Hospital of Divrigi is located in the central eastern partof Turkey, in Divrigi, Sivas. The historical facility consists of a monumental mosque anda two-story hospital, which are adjacent to each other. The structure dates back to13th century Mengujekids period and has been listed by the UNESCO as a World Heritagesince 1985. Great Mosque and Hospital of Divrigi is particularly notable for its monumentalstone portals that are decorated with three-dimensional ornaments carved fromstone. The structural system of the monument consists of multi-leaf stone masonrywalls and stone piers that support the roof structure which consists of stone and brickarches and vaults. The structure is located about 90 km away from the North AnatolianFault Line, that has been causing several destructive earthquakes. Consequently, thestructure is prone to destructive seismic activities. In this study, after a briefintroduction on the structural system and current condition of the structure, thestructural performance of the Great Mosque and Hospital of Divrigi is investigatedthrough site observations and structural analyses. For this purpose, linear and nonlinear 3Dfinite element models of the structure are developed and the structure is examined under theeffects of vertical loads and seismic actions. In the light of the analyses results,recommendations for potential interventions are outlined for further preservation of thestructure.