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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. Source

Buyukkamaci N.,Dokuz Eylul 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. Source

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. Source

Kasmer T.,Ministry of Environment and Urbanization | Ulusay R.,Hacettepe University | Genis M.,Bulent 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. Source

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. Source

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