Kasmer T.,Ministry of Environment and Urbanization |
Ulusay R.,Hacettepe University |
Genis M.,Bülent Ecevit University
Engineering Geology | Year: 2013
The Zelve Open-Air Museum, consisting of three valleys, is one of the oldest historical semi-underground settlements in the Cappadocia Region of Turkey which was designated as a World Heritage Site in 1985 by UNESCO. Particularly in the first valley, there are a lot of underground openings of different sizes carved in a soft tuff next to the valley cliffs used for cliff settlement in the past and several antique churches with some geo-engineering problems. In addition, steep natural slopes in this valley are prone to toe erosion resulting in stability problems. In this study, it is aimed to investigate engineering characteristics of the surrounding tuff and factors affecting them, and to assess the effect of rate of toe erosion on the stability of steep valley slopes and structural stability of some selected typical underground openings with large spans subjected to spalling. For these purposes, some observational, experimental and numerical modelling studies were conducted. Experimental results indicate that strength and deformability properties of the weak tuff surrounding the openings drastically reduce when it becomes wet or saturated. This situation suggests that possibility of occurrence of failures is expected to be higher in rainy seasons due to increase in water content of the tuff. Experimental results also suggest that spalling commonly observed in the valley is related with freezing-thawing and wetting-drying cycles in nature and that the process of freezing and thawing accelerates further the degradation of the rock. The long-term measurements at selected locations suggest that erosion in the tuff is important, which increases particularly in winter and spring seasons and results in the loss of support accelerating the occurrence of further slope failures. The 2-D numerical solutions indicate that no significant change in shear and tensile stresses in steep valley slopes prone to toe erosion would be expected after 100. years. However, the solutions obtained from the 500- and 1000-year scenarios suggest that failure zones due to the tensile stresses would develop in the form of slabs with thicknesses of 50-60. cm and 90-100. cm, respectively, which would break off from the slope and fall down. The results from 3-D numerical solutions indicate that failure (yield) zone resulting from tensile stresses around the semi-underground openings will develop parallel to the sidewalls. These results confirm the observed spalling of the tuff in the form of slabs parallel to the walls of the openings. © 2013 Elsevier B.V.
Binici B.,Middle East Technical University |
Yakut A.,Middle East Technical University |
Ozcebe G.,Ankara University |
Erenler A.,Ministry of Environment and Urbanization
Earthquake Spectra | Year: 2015
A law known as the "Urban Renewal Law" for risk mitigation was passed in Turkey in May 2012. The major focus of the law is to reduce the expected seismic risk due to the vulnerability of existing buildings. For this purpose, new provisions are set forth to investigate and to classify seismically vulnerable residential buildings as quickly as possible. Afterward, such deficient buildings are demolished, and new buildings are constructed through the financing options provided by the government. Although the strengthening of deficient buildings still remains an option, it is not encouraged, especially for older structures with critical deficiencies. In this article, the technical provisions for seismic risk assessment are presented. Special emphases are given to member ductility and deformation limits to be used in linear elastic assessment procedures. A simple procedure, given as an option, to consider the beneficial presence of infill walls at low deformations is presented. Finally, results are given for case study buildings. © 2015, Earthquake Engineering Research Institute.
Bosca A.V.,Ministry of Environment and Urbanization |
Sanin S.L.,Hacettepe University
Journal of Residuals Science and Technology | Year: 2015
Biotoxicity and low temperature are among the challenges of biodegradation as well as microbial transport in in-situ bioremediation applications. This study investigates the effect of low temperature, high and low concentrations of phenol, on biodegradability and the surface properties of Rhodotorula glutinis which may be instrumental to develop control mechanisms in engineering applications. Results showed that Rhodotorula glutinis is able to grow at low phenol (< 0.5 g/L) and glucose (1.0 g/L) concentrations. Microbial growth rates of Rhodotorula glutinis is the highest at 25°C for phenol fed reactors. Temperature and type of carbon source affected the total amount of extracellular polymeric substances (EPS) and the relative amounts of EPS constituents. Phenol fed Rhodotorula glutinis, at 4°C, were found to be hydrophobic whereas Rhodotorula glutinis showed less hydrophobic characteristics at 25°C, regardless of the carbon source. Surface hydrophobicity of Rhodotorula glutinis is related to the distribution of carbohydrate and proteins in the EPS. © 2015 DEStech Publications, Inc.
Gokmen M.,Ministry of Environment and Urbanization |
Gokmen M.,Research Association of Rural Environment and Forestry
Hydrology and Earth System Sciences | Year: 2016
We present a regional assessment of the spatiotemporal trends in several hydro-climate variables from 1979 to 2010 in Turkey, one of the countries of the eastern Mediterranean vulnerable to climate change, using the two reanalysis products of the ECMWF: ERA-Interim and ERAInterim/ Land. The trend analysis revealed that an average warming of 1.26 °C [0.8-1.8] occurred in Turkey from 1979 to 2010, with high confidence intervals (95-99 %, mostly). Geographically, the largest warming (up to 1.8 °C) occurred in the western coastal areas next to the Aegean Sea and in the southeastern regions. The air temperature trends were generally confirmed by the in situ data from about 100 weather stations around the country, though in situ data indicated slightly higher trends ranging from 1 to 2.5°. With respect to the regional trends in hydrological variables, ERA-Interim and ERA-Interim/Land revealed quite different pictures: the ERA-Interim dataset indicated that there have been significant decreasing trends of precipitation, snow water equivalent (SWE) and runoff in some parts of inner/southeastern Anatolia (a total decrease of up to 250mm in the upstream of the Euphrates, Kizilirmak and Seyhan basins), while ERAInterim/ Land showed no or minor trends in the same areas. Based on the extensive comparisons with precipitation and SWE gauge data, we can suggest that the hydrological trends shown by the ERA-Interim/Land dataset, which is said to be a model improvement, are relatively closer to the observations. From the hydrological trends revealed by the ERA-Interim/Land dataset, we can conclude that, despite the strong warming trends over Turkey from 1979 to 2010, there have been no widespread and strong hydrological trends for the same period throughout the country. In this regard, we can suggest that the impacts of global warming on the water cycle are not straightforward, especially at the regional scale, and future climate simulations indicating considerable reductions in precipitation along with the significant increases in temperatures throughout the Mediterranean and the Middle East by the end of the twenty-first century need to be dealt with cautiously. © Author(s) 2016.
Buyukkamaci N.,Dokuz Eylül University |
Alkan H.S.,Ministry of Environment and Urbanization
Resources, Conservation and Recycling | Year: 2013
The water reuse applications are becoming increasingly important in Turkey due to fresh water scarcity problems. However, the success of reuse practices depends on the public's acceptance. Therefore, this study was designed to determine the public awareness, and the potential for acceptance, of reuse applications in Turkey by way of a survey carried out for this purpose. 500 questionnaires were sent to different regions of Turkey and 375 of them were returned. The study indicated that both women and men have concerns about usage of wastewater, especially regarding the use of treated wastewater as drinking water. Results also showed that the area of greatest concern among the public is the health risks associated with recycled water. Respondents of both genders felt that treated wastewater reuse for applications not involving close personal contact was acceptable, due to reduced health risk concerns. On the other hand, the cost of reclamation is another major public concern. © 2013 Elsevier B.V. All rights reserved.
Avci-Karatas C.,Ministry of Environment and Urbanization |
Celik O.C.,Technical University of Istanbul
NCEE 2014 - 10th U.S. National Conference on Earthquake Engineering: Frontiers of Earthquake Engineering | Year: 2014
Intense research is being done in the field of Buckling-Restrained Brace (BRB) technology to seek more cost effective and reliable solutions. To investigate performance under cyclic loading, two full scale steel-core BRB specimens (labeled as TURKBRACE BRB-SCI and TURKBRACE BRB-SCII) with simple end details have been designed to AISC specification, manufactured, and cyclically tested in the Structural and Earthquake Engineering Laboratory (STEEL) of the Technical University of Istanbul. A diagonal configuration for the braces in an L-shaped testing setup was used. These specimens use single, large diameter bolted (pinned) end connections and rectangular shaped steel core plates as the core materials of S235JR and S355JR. The core is surrounded by a thin steel tube infilled with a high strength (64MPa) grout material as the buckling restraining system. A teflon based unbonded surface system was used on the core member's surface. Experimental results show that maximum drifts of 3.17% and 3.55% were obtained for BRB-SCI and BRB-SCII, respectively. Note that no fractures in the welds or any signs of local or global instability were observed during testing. Experimental hysteretic curves, behavioral values such as maximum strength in tension and compression cycles, hysteretic damping (ξ max = 40%), and cumulative hysteretic energy dissipation values are given. These observations reveal that BRB-SCI performed slightly better than BRB-SCII since this brace used a longer core length, resulting in larger dissipated energy, and better hysteretic response. A maximum displacement ductility of μ=10 was obtained for both BRBs.
Sahmaran M.,Gazi University |
Anil O.,Gazi University |
Lachemi M.,Ryerson University |
Yildirim G.,Gazi University |
And 2 more authors.
ACI Structural Journal | Year: 2015
The objective of this study was to evaluate the effect of corrosion level on shear behavior of engineered cementitious composite (ECC) beams. Reinforced normal concrete (R-NC) specimens with compressive strength equal to the ECC specimens were also used for control purposes. Ten reinforced concrete beams (five ECC and five NC) with dimensions of 150 x 220 x 1400 mm (5.91 x 8.66 x 55.12 in.) were manufactured for the study. Using accelerated corrosion through the application of a constant current of 1 ampere, four levels of corrosion were established at 5%, 10%, 15%, and 20% of mass loss of the reinforcing bars. To ensure the highest probability of shear failure mode, all beams were tested under a four-point loading system with a shear span-effective depth ratio of 2.5. General structural behavior, strength, stiffness, failure mode, and energy absorption capacities of ECC and R-NC beams subjected to different corrosion levels were evaluated and compared. Experimental results showed a high correlation between calculated mass loss and measured mass loss in reinforcing bars due to accelerated corrosion. Compared to NC, ECC beams exhibited significantly higher strength, stiffness, and energy absorption capacity, along with superior performance in terms of the restriction of damage caused due to corrosion. The increase in corrosion level negatively influenced the structural behavior of the ECC beams tested. © 2015, American Concrete.
Sezgin D.,Ministry of Environment and Urbanization |
Varol C.,Gazi University
Metu Journal of the Faculty of Architecture | Year: 2012
In Turkey, the pace of industrialization and the rapid increase of urban population cause cities and their hinterland to expand, thus some of the urban functions are located outside the urban settlement boundaries. The discontinuous and disjointed settlements lead to a new growth model in the metropolitan, namely the urban sprawl. This growth mainly affects and transforms the agricultural land around cities, which is a vital natural resource for the continuity of ecosystems, and thus, has to be used efficiently. In this study, emphasizing the nature of the agricultural land, which is non-renewable and ir-reproducible, the effects of urban sprawl induced by spatial growth are explained in the case of the Ankara Metropolitan Area. The misuse of fertile agricultural land around the city is identified by using the data of the proposed macroforms in development plans and landuse maps, wich delineate an overall picture of the spatial transformation. Results show that from the 1950s to the 2000s, the rapid spatial growth and consequent dispersion of urban functions to the periphery have degraded the fertile agricultural land, in particular on the west and on the southwest axes.
Ergene Senturk D.,Ministry of Environment and Urbanization |
Ergene Senturk D.,Middle East Technical University |
Alp E.,Middle East Technical University
Waste Management and Research | Year: 2016
Landfilling is the most preferred solid waste disposal method in Turkey owing to both economic and technical reasons. However, beside the sanitary landfills there are also hundreds of uncontrolled waste sites located throughout Turkey, which are often left either abandoned or burning. Because there is a lack of legislative guidelines governing the closure and rehabilitation of these dumpsites, the municipalities that are responsible for waste management do not initiate the proactive strategies required for the closure of these sites. In this study, a method based on a multi-criteria analysis is conducted for different dumpsites in Turkey to evaluate the level of negative impacts on the environment. This method is based on the use of environmental indices for a quantitative assessment of the landfills, such as environmental interaction between the source and the receptors, environmental values of the receptors, and operational conditions. It was possible to assess the robustness of the proposed methodology since the pre- and post-groundwater quality monitoring data was available from the study sites that were closed and rehabilitated in 2014. The results of this study show that the method based on a multi-criteria analysis is an effective tool while in the preliminary planning stages of closure and rehabilitation activities of uncontrolled waste landfills. © International Solid Waste Association.
Kasmer O.,Ministry of Environment and Urbanization |
Ulusay R.,Hacettepe University
Environmental and Engineering Geoscience | Year: 2013
The Cappadocia region, with its very distinct culture, is one of the attractive tourist sites of Turkey due to its spectacular and unique landforms and historical heritage. In this region, the structures carved into thick and soft tuffs have survived and kept their integrity for about 12-13 centuries. The Zelve Open Air Museum, consisting of three valleys, is one of the oldest antique semi-underground settlements in the region and is designated as a World Heritage Site in Turkey. Although it was closed to human habitation due to collapses, which occurred within some of the rock-hewn structures and resulted in three casualties in 1950s, it is open to tourists. Particularly in the first valley, there are a lot of rock-hewn openings of different sizes and several churches with some geo-engineering problems. This study aims to assess the geo-engineering characteristics of the soft tuffs surrounding the rock-hewn historical structures and environmental conditions in the first valley of the Zelve Open Air Museum and their possible effects on the geo-engineering problems observed in this museum. The results mainly suggest that the strength of rock is reduced drastically under saturated conditions, and the processes of freezingthawing and wetting-drying accelerate further degradation of rock under saturated conditions. Over a period of about five years, the amount of erosion, which mainly resulted from the two strong agents of rainfall and wind, ranged between 1.07 and 6.21 mm. Assuming that the erosion is homogeneous, determined annual average erosion ranges between 0.21 and 1.24 mm/yr. These observations suggest that erosion is an important phenomenon in this site and increases particularly in the winter and spring seasons. The failure modes, such as falling, sliding, bending, spalling, and slabbing, observed in the valley are considered to be mainly associated with deterioration and erosion of tuffs near vertical and laterally persistent discontinuities generally oriented perpendicular and parallel to the valley, and property changes due to cyclic freezing-thawing and wetting-drying processes. Spalling and slabbing occurring in cliffs and semi-underground openings are the indicators of yielding of rock. These phenomena result in the formation of slabs with different thicknesses, and consequently cause a change in geometry of the openings in the valley to trigger failures.