Civil Engineering / İnşaat Mühendisliği
Permanent URI for this collectionhttps://hdl.handle.net/11147/13
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Article Citation - WoS: 1Citation - Scopus: 2Consolidation of a Bath Ruin in an Archaeological Site(Taylor and Francis Ltd., 2022) Durmuşlar, Feyza; Turan, Mine; Yücetürk, Kutay; Aktaş, EnginThe study has focused on consolidation of a historical bath ruin in an archaeological site. Cevher Pasa Bath, which is located in Tabae archaeological site in Denizli, Turkey and dated to the 15th century, presents structural problems. The aim of the study is to propose a framework for planning consolidation of the ruins of Cevher Pasa Bath so that conservation work regarding similar masonry ruins in archaeological sites can be guided. Thus, methods of architectural restoration and civil engineering are combined in an interdisciplinary scope. Provision of temporary shoring as an emergency intervention, consolidation and presentation of the ruin within the scope of an interdisciplinary restoration project, and monitoring of the asset within the frame of a monument management plan are suggested, respectively. Structural analysis considering stress and overturning moment checks are performed. Consolidation work includes only supporting of arch remains. Some walls of the ruin are weaker than other parts. These parts need further detailed analysis, and if necessary, further consolidation and strengthening are to be carried out. The monument management plan points out the necessity of collaboration of local and central administrations, and also non-governmental organisations.Conference Object Roc Curves for Evaluating Sensor Performance as Low Energy Impacts Damage a Composite Wing(DEStech Publications Inc., 2009) Aktaş, Engin; Seaver, M.Eight fiber Bragg gratings and 3 ICP accelerometers attached to the upper surface of a foam core composite wing (1320 mm X 152.4 mm X 13.4 mm) were used to record the wing's response to broad band (0 - 1500 Hz) Gaussian excitation following a series of low energy (-6.5 J) impacts to the surface of the wing. For each damage level, at least 15 measurements were made over a period of three days to enable a statistical evaluation of each sensor's performance. Damage detection relied on measuring nonlinearity in the response data using a second order correlation metric called the Bicoherence. The amplitudes of any peaks seen in the Bicoherence were compared with thresholds determined from the variance in the off diagonal terms in the Bicoherence measurement. This approach allows the evaluation of both the probability of detection (POD) and the probability of false alarms (PFA) for each measurement without the need for a healthy baseline. The results show that all eight FBGs out perform the accelerometers and that one FBG in particular is more sensitive to nonlinearity than the others. The measurement sensitivity of the Bicoherence is also compared with static tip deflection measurements.Article Citation - WoS: 39Citation - Scopus: 40Mode-I Fracture Toughness of Carbon Fiber/Epoxy Composites Interleaved by Aramid Nonwoven Veils(Techno Press, 2019) Beylergil, Bertan; Tanoğlu, Metin; Aktaş, EnginIn this study, carbon fiber/epoxy (CF/EP) composites were interleaved with aramid nonwoven veils with an areal weight density of 8.5 g/m(2) to improve their Mode-I fracture toughness. The control and aramid interleaved CF/EP composite laminates were manufactured by VARTM in a [0]4 configuration. Tensile, three-point bending, compression, interlaminar shear, Charpy impact and Mode-I (DCB) fracture toughness values were determined to evaluate the effects of aramid nonwoven fabrics on the mechanical performance of the CF/EP composites. Thermomechanical behavior of the specimens was investigated by Dynamic Mechanical Analysis (DMA). The results showed that the propagation Mode-I fracture toughness values of CF/EP composites can be significantly improved (by about 72%) using aramid nonwoven fabrics. It was found that the main extrinsic toughening mechanism is aramid microfiber bridging acting behind the crack-tip. The incorporation of these nonwovens also increased interlaminar shear and Charpy impact strength by 10 and 16.5%, respectively. Moreover, it was revealed that the damping ability of the composites increased with the incorporation of aramid nonwoven fabrics in the interlaminar region of composites. On the other hand, they caused a reduction in in-plane mechanical properties due to the reduced carbon fiber volume fraction, increased thickness and void formation in the composites.Article Construction Techniques of Hayat Houses: Two Case Studies in the Vicinity of Izmir(American Society of Civil Engineers (ASCE), 2019) Turan, Mine; Aktaş, Engin; Mamaklı, Fatma Sezgi; Kaplan, ZişanThis study aims to contribute to the analytic studies on constructional aspects of the hayat house typology with an eye on its historical evolution for conservation purposes. The method used included a review of the surviving examples of the typology in Izmir and its vicinity and the selection of two intact examples whose structural components are legible: one from the earliest period and the other from the latest period. The examples selected are Kerimaga Konagi in Birgi, odemis, Izmir and a house in Kirkagac, Soma, Manisa. The early example (probably eighteenth century, constructed over the remains of an older house) sustains the traditional box system in its wooden upper story that integrates with the roof. The provision of level differences on the upper floor, the traditional relationship of the sitting level-window design, and masonry base are its authentic features. The late example (probably early twentieth century) presents signs of modernization, such as the establishment of a systematic wooden roof and wall frames in relation to each other, lack of diagonals in the perpendicular wall frame, avoidance of projections, and relatively elongated windows placed at higher positions.Article Citation - WoS: 6Citation - Scopus: 4Conservation-Aimed Evaluation of a Historical Aqueduct in Izmir(American Society of Civil Engineers (ASCE), 2019) Mamaklı, Fatma Sezgi; Turan, Mine; Aktaş, Engin; Vardaroğlu, MustafaThe seventeenth century was the era in which Izmir became an international commercial center in the eastern Mediterranean. The vizier of the era, Koprulu Fazil Ahmet Pasa, noticed the scarcity of potable water in relation with the increasing population at the center of this harbor city and ordered the construction of an aqueduct on Melez Valley. The Veziraga Aqueduct was constructed in 1674. This article aims to identify historical, architectural, and structural characteristics of the Veziraga Aqueduct so that its heritage values and conservations problems can be understood. The geographical and historical characteristics of the Veziraga Aqueduct are described by taking the effects of site and the sociocultural situation of city into consideration. The architectural characteristics of the aqueduct are prepared by using the site survey data to reveal the current condition and find out the original state. Seismic behavior of the aqueduct is investigated by using two approaches: analytical equivalent static analysis and finite-element analysis. The historical, architectural, and structural characteristics of the Veziraga Aqueduct prove its historical, documentary, and aesthetic values.Article Citation - WoS: 23Citation - Scopus: 26Experimental and Statistical Analysis of Carbon Fiber/Epoxy Composites Interleaved With Nylon 6,6 Nonwoven Fabric Interlayers(SAGE Publications Inc., 2020) Beylergil, Bertan; Tanoğlu, Metin; Aktaş, EnginThermoplastic interleaving is a promising technique to improve delamination resistance of laminated composites. In this study, plain-weave carbon fiber/epoxy composites were interleaved with nylon 6,6 nonwoven fabrics with an areal weight density of 17 gsm. The carbon fiber/epoxy composite laminates with/without nylon 6,6 nonwoven fabric interlayers were manufactured by VARTM technique. Double cantilever beam fracture toughness tests were carried out on the prepared composite test specimens in accordance with ASTM 5528 standard. The experimental test data were statistically analyzed by two-parameter Weibull distribution. The results showed that the initiation and propagation fracture toughness Mode-I fracture toughness of carbon fiber/epoxy composites could be improved by about 34 and 156% (corresponding to a reliability level of 0.50) with the incorporation of nylon 6,6 interlayers in the interlaminar region, respectively. The results also revealed that the percent increase in the propagation fracture toughness value was 67 and 41% at reliability levels of 0.90 and 0.95, respectively.