Civil Engineering / İnşaat Mühendisliği
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Article Citation - WoS: 61Citation - Scopus: 60Performance of Structures in İzmir After the Samos Island Earthquake(Springer, 2022) Yakut, A.; Sucuoǧlu, H.; Binici, B.; Canbay, E.; Dönmez, C.; Ilki, A.; Ay, B.Ö.The October 30, 2020 Earthquake caused unexpectedly significant damage in İzmir considering its distance to the city. This paper evaluates the recorded ground motions, summarizes the performance of structures affected from the earthquake with emphasis on the reasons of damage. A detailed damage assessment was carried out by the Earthquake Engineering Research Center of Middle East Technical University to compile data on the damage of RC and masonry buildings. It was observed that majority of the damage was concentrated in the Bayraklı district due to its peculiar soil properties where many 7–10 story mid-rise RC buildings suffered heavy damage and collapse. The level of amplified ground motions combined with deficiencies of apparently non-code compliant buildings exacerbated the damage. The main reasons of damage were mainly attributed to the presence of soft stories, lack of proper detailing, poor construction quality, presence of heavy overhangs, and hence significant lack of code-compliance in essence. The influence of infill walls on seismic performance of deficient and inadequate buildings was clearly seen in this earthquake. This paper also discusses seismic code requirements in effect and their influence on the observed building performance. The recorded ground motions were compared with the code spectra to evaluate the performance of the buildings. The code response spectra were found to be well above the recorded ground motion spectra at the sites where significant damage was observed. © 2021, The Author(s), under exclusive licence to Springer Nature B.V.Article Citation - WoS: 7Citation - Scopus: 5Meteorological Drought and Trend Effects on Transboundary River Basins in Afghanistan(Springer, 2023) Hayat, Ehsanullah; Tayfur, GökmenAfghanistan, as a landlocked country located within central and southwestern Asia, has an arid to semi-arid climate. Most of the people are involved in agricultural activities, and a major part of the country's gross domestic product depends on agriculture, but the country has the lowest water storage capacity. Consecutive periods of drought and rapid snowmelt due to climate change have made it more challenging for suitable water resource management practices. This study investigates the historical meteorological drought characteristics across the whole country by employing the Reconnaissance Drought Index for the period 1979-2019 using data from 55 meteorological stations. Trends in precipitation and temperature are also investigated using the Mann-Kendall's and the Sen's slope statistical tests. A four-decadal countrywide drought map is generated. Extreme and severe droughts were observed in 1999 and 2000 across the whole country. Moderate drought events have started to occur with a frequency of 3 to 5 years since 1999. The decadal annual rainfall values in each river basin indicate that rainfall has decreased in the last two decades with a significant decline in 1999-2008. The trends of increase in temperature and decrease in precipitation are indications of rapid climate change in the country, especially in the south, west, and southwest regions. Due to the intensity and frequency of the droughts, river flow rates have decreased; and therefore, there is a need for the upstream and downstream neighboring countries to come to terms with the phenomenon of a new normal in the hydrological cycle and accordingly revise new water sharing treaties.Correction 3D modelling of surface spreading and underground dam groundwater recharge: Egri creek subbasin, Turkey(Springer, 2023) Şahin, Yavuz; Tayfur, GökmenArticle Citation - WoS: 9Citation - Scopus: 8Effect of Drainage Conditions on Cpt Resistance of Silty Sand: Physical Model and Field Tests(Springer, 2023) Ecemis, Nurhan; Arık, Mustafa Sezer; Taneri, HazalThe influence of drainage conditions on cone penetration test (CPT) resistance and the excess pore pressure during cone penetration in sand and silty sand are examined using field and physical model tests. Drainage can generally occur in saturated clean sand and silty sand under certain conditions. This work aims to understand and explain the effect of sand and silty sand drainage conditions on CPT resistance and pore pressure through the coefficient of consolidation (c h) and penetration rate (v). The physical model test results indicate the significant effect of excess pore pressures and their dissipation rates, depending on the coefficient of consolidation (silt content) and the penetration rate on cone resistance. For the same relative density, normalized CPT resistance decreases as there is a reduction in c h (or an increase in silt content) or an increase in penetration rate. The difference in CPT resistance in silty sand is attributed to drainage conditions. Finally, the results revealed in this study and the field test data reported in the literature were combined to develop an equation for the effect of drainage conditions on excess pore water pressure and CPT resistance. © 2023, The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.Book Part Design and Construction of a Test Setup To Investigate Ground Settlement Response of Large-Scale Masonry Building Models(Springer, 2023) Liu, Yiyan; Dalgıç, Korhan Deniz; Yeşilyurt, Cennet; Gülen, Burcu; Açıkgöz, Sinan; Maraşlı, Muhammed; İlki, AlperUnderground construction activities such as tunnelling and deep excavations in urban areas may impact a significant number of surface structures and cause damage. Tunnelling-induced damage can often be repaired, but at great expense, due to significant repair costs and associated project delays. Within this context, damage caused by excavation-induced ground movements on heritage masonry buildings requires further attention, due to the cultural value and vulnerability of these assets. There is a need for experimental studies to better understand the structural response of these buildings to excavation-induced ground movements. In this study, a test setup was designed and constructed to examine the response of an experimental building model, replicating historic masonry structures, against differential settlement effects. The settlement apparatus relies on controlled jacking of large steel beams to apply differential displacements to the building. A specific tunneling scenario was considered for the design of the settlement apparatus. The constructed test setup is validated by evaluating the displacement profiles of the steel beam for different tests, with or without building. Differences between the differential settlements experienced by the steel beam and the building highlights how building weight and progressive damage may increase compliance to ground movements. © 2023, The Author(s), under exclusive license to Springer Nature Switzerland AG.Article Citation - Scopus: 1Relationship Between Abrasion, Fragmentation and Thermal Weathering Resistance of Aggregates: Regression and Artificial Neural Network Analyses(Springer, 2023) Gökalp, İslam; Kaya, Orhan; Uz, Volkan EmreFor being used in pavement construction, properties of aggregates must satisfy the minimum requirements specified by highway agencies or institutions. The properties of the aggregates are determined by many tests lasting anywhere between a couple of hours to a few weeks depending on the type of the test. If good correlations can be established between the tests taking longer time and the ones taking comparably shorter time, there might be no need to conduct these longer time-taking tests for the sake of time. The aim of this study is to investigate the relationships between abrasion, fragmentation, and thermal weathering resistances of different aggregate types. To accomplish this aim, aggregates with different origins (natural and slags) were tested and correlative analyses utilizing regression analysis and artificial neural network (ANN) models were performed to establish relationships between the results of these test methods. It was found that good correlations can be established especially with ANN models and significant amount of time and effort can be saved with these developed models. © 2023, The Author(s), under exclusive licence to Chinese Society of Pavement Engineering.Article Citation - WoS: 4Citation - Scopus: 53d Modelling of Surface Spreading and Underground Dam Groundwater Recharge: Egri Creek Subbasin, Turkey(Springer, 2023) Şahin, Yavuz; Tayfur, GökmenThis study investigated surface spreading and underground dam recharge methods to replenish groundwater in Turkey's Egri Creek Sub-basin of the Kucuk Menderes River Basin. A three-dimensional numerical model was employed for this purpose. Field and lab data are provided to the model for realistic simulations. Pumping test results were used to determine the aquifer parameters. The laboratory works involved sieve analysis, permeability tests, and porosity and water content prediction. The numerical model's boundary conditions were determined from the geological and hydrogeological characteristics of the study area. Initial conditions were expressed regarding water content and pressure head in the vadose zone. The numerical model was satisfactorily validated by simulating water levels in three different pumping wells in the study area. Seven different scenarios, each having a different pool size, were investigated for the surface spreading recharge method. The results showed that a pool size of 30 x 30 m with a 6-m depth basin was the most optimal choice, raising the groundwater level to about 29.3 m. On the other hand, it was found that an underground dam could raise the levels by an average of 9.5 m, which might not be significant to warrant the construction.Article Citation - WoS: 2Citation - Scopus: 2Assessment of Future Water Demand in a Semiarid Region of Turkey: a Case Study of Tahtali–seferihisar Basin(Springer, 2023) Karahan, S. M.; Elçi, ŞebnemWater is a vital resource for society and nature, and its scarcity has consequences in all aspects of existence. Today, issues including the inability to preserve the status of existing water resources and excessive water withdrawal are causing the amount of water to diminish day by day. Furthermore, factors such as urbanization and industrialization, population growth, water quality degradation owing to agricultural pesticides, and climate change, all have a negative impact on water supplies. A basin-based water management analysis was carried out in this study by applying the "Integrated Water Resources Management" strategy to the Tahtalı–Seferihisar sub-basin in Turkey, where water stress is expected in the future. Using the WEAP (Water Evaluation and Planning System) model, the hydrological (precipitation, flow, evaporation) data of important water resources for the basin and Izmir (Tahtalı, Seferihisar, Ürkmez, and Kavakdere Dams) were used to predict the availability of water resources in the future, and several possible scenarios for water demands/supplies were analyzed. The water budget balances projected in 2050 have been calculated by considering six different scenarios: Reference Scenario, Report Consumption Scenario, Optimistic Case Scenario, Pessimistic Case Scenario, Return Flow Scenario, and Various Forecast Scenario. The water balances that can be obtained in each scenario under various situations were computed and compared. For all considered scenarios, unmet water demand in the basin is found to be significant (157.52 hm3 in the Optimistic Case Scenario and 373.16 hm3 in the Pessimistic Case Scenario).Article Citation - WoS: 4Citation - Scopus: 4Seismic Vulnerability Assessment of an Unanchored Circular Storage Tank Against Elephant's Foot Buckling(Springer, 2022) Bektaş, Nurullah; Aktaş, EnginPurpose Seismic vulnerability assessment of liquid containing storage tanks is the most vital relevance for industrial plants and society safety to endure damage during impending earthquakes. Because such systems also play an essential role in the public lifeline and also ensure continued use in emergencies. Furthermore, considering that the material contained in individual plants could be hazardous, requisite precautions have paramount importance against undesired leakage. The high internal pressure and axial forces exerted by the liquid in the steel tanks near the tank wall bottom produce elastic-plastic buckling, also known as Elephant's Foot Buckling (EFB). As far as the authors are aware, no study has been carried out that involves a critical assessment and comparison of IDA and truncated IDA-based EFB failure criterion. This study provides insight into incremental dynamic analysis (IDA) and truncated IDA-based seismic evaluation of cylindrical unanchored steel storage tanks by employing a developed pressure-based surrogate modeling approach. For this purpose, probability-based seismic assessment of a representative sample is considered based on IDA and truncated IDA approaches to identify the potential of the EFB failure and to explore potential enhancements in the sophisticated structural analysis model to prevent the hazardous effects of impending earthquakes. Methods Due to the significance of industrial plants for public safety and benefit, the structural response evaluation methods for different types of storage tanks have been widely reported. In the literature, the most comprehensive analytical assessment methodology is the IDA approach, in which nonlinear time-history analyses are considered in the finite element analysis model to assess the structural model's seismic performance. Results To generate fragility curves, both IDA approaches are employed, taking into consideration and ignoring uncertainty of material properties. The values of the two methods-based fragility curves approach each other as the magnitude of dispersion increases. Conclusion The two fragility curves give the probability of failures close to each other as the dispersion amount increases while considering the uncertainty of the material properties. In addition, fragility curves generated based on the truncated IDA have been found to give a higher probability of failure, up to 32.5 percent. When compared to the IDA-based fragility curves, the truncated IDA-based fragility curves were found to be on the conservative side.Correction Cpt-Based Liquefaction Resistance of Clean and Silty Sands: a Drainage Conditions Based Approach Nurhan Ecemis (aug, 10.1007/S10518-022-01501-0, 2022)(Springer, 2022) Arık, Mustafa Sezer; Ecemiş, Nurhan; Monkul, Mehmet Murat; Tütüncü, Yunus Emre