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91.
This study is aimed at comparing the seismic performance of steel chevron braced frames (CBFs) with and without fluid viscous dampers (FVDs) as a function of the characteristics of the near‐fault (NF) ground motion and FVD parameters. For this purpose, comparative nonlinear time history (NLTH) analyses of single and multiple storey CBFs with and without FVDs are conducted using NF ground motions with various velocity pulse periods scaled to have small, moderate and large intensities. Additionally, NLTH analyses of single‐ and four‐storey CBFs with FVDs are conducted to study the effect of the damping ratio and velocity exponent of the FVD on the seismic performance of the frames. The analyses results revealed that the seismic performance of the CBFs without FVDs is very poor and sensitive to the velocity pulse period and the intensity of the NF ground motion due to brace‐buckling effects. Installing FVDs into the CBFs significantly improved their seismic performance by maintaining their elastic behaviour. Furthermore, FVDs with smaller velocity exponents and larger damping ratio are observed to be more effective in improving the seismic performance of the CBFs subjected to NF earthquakes. However, FVDs with damping ratios larger than 50% do not produce significant additional improvement in the seismic performance of the CBFs. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
92.
Murat Ayaz Erkutay Tasdemirci Huseyin Yuksel Volkan Aygul 《Arabian Journal of Geosciences》2018,11(22):725
The condition of the ambient air must be continuously checked to detect hazardous gas leakage and ensure the safety of employees in hazardous gas production and storage areas. Detection and elimination of hazardous gas leaks can be done with various complex measurement, safety, and disposal systems. These measurement systems consist of different types of sensor and require control and monitoring system. This leads to high investment and operating costs. In this study, semi-continuous measurement system automation with a single set of sensors working by taking air samples from different points over specific periods has been designed to reduce investment, operation, and maintenance repair costs. In the design, the measurement points are divided into zones and codes in the automation system. Thus, it is aimed to keep a constant record of what the air sample is coming from and what its content is. As a result, it has been determined that it is possible to establish a measurement and automation system similar to existing hazardous gas measurement systems with less investment and operating costs. The proposed automation system has been applied in the industrial storage area. In addition, a cost analysis has been performed and compared with conventional systems. 相似文献
93.
94.
Possible long-term seismic behaviour of the Northern strand of the North Anatolian Fault Zone, between western extreme of
the 1999 İzmit rupture and the Aegean Sea, after 400 AD is studied by examining the historical seismicity, the submarine fault
mapping and the paleoseismological studies of the recent scientific efforts. The long-term seismic behaviour is discussed
through two possible seismicity models devised from M
S ≥ 7.0 historical earthquakes. The estimated return period of years of the fault segments for M1 and M2 seismic models along
with their standard deviations are as follows: F4 segment 255 ± 60 and 258 ± 12; F5 segment 258 ± 60 and 258 ± 53; F6 segment
258 ± 60 and 258 ± 53; F7 segment 286 ± 103 and 286 ± 90; F8 segment 286 ± 90 and 286 ± 36. As the latest ruptures on the
submarine segments have been reported to be during the 1754–1766 earthquake sequence, and the 1912 mainshock rupture has been
evidenced to extend almost all over the western part of the Sea of Marmara, our results imply imminent seismic hazard and,
considering the mean recurrence time, a large earthquake to strike the eastern part of the Sea of Marmara in the next two
decades. 相似文献
95.
A Simplified Failure Criterion for Intact Rocks Based on Rock Type and Uniaxial Compressive Strength 总被引:1,自引:1,他引:1
Jiayi Shen Rafael Jimenez Murat Karakus Chaoshui Xu 《Rock Mechanics and Rock Engineering》2014,47(2):357-369
The uniaxial compressive strength (UCS) of intact rock, which can be estimated using relatively straightforward and cost-effective techniques, is one of the most practical rock properties used in rock engineering. Thus, constitutive laws to represent the strength and behavior of (intact) rock frequently use it, along with additional intrinsic rock properties. Although triaxial tests can be employed to obtain best-fit failure criterion parameters that provide best strength predictions, they are more expensive and require time-consuming procedures; as a consequence, they are often not readily available at early stages of a project. Based on the analysis of an extensive triaxial test database for intact rocks, we propose a simplified empirical failure criterion in which rock strength at failure is expressed in terms of confining stress and UCS, with a new parameter which can be directly estimated from the UCS for a specified rock type in the absence of triaxial test data. Performance of the proposed failure criterion is then tested for validation against experimental data for eight rock types. The results show that strengths of intact rock estimated by the proposed failure criterion are in good agreement with experimental test data, with small discrepancies between estimated and measurements strengths. Therefore, the proposed criterion can be useful for preliminary (triaxial) strength estimation of intact rocks when triaxial tests data are not available. 相似文献
96.
Choosing a municipal landfill site by analytic network process 总被引:2,自引:1,他引:2
Mufide Banar Barbaros Murat Kose Aysun Ozkan Ilgin Poyraz Acar 《Environmental Geology》2007,52(4):747-751
In this study, analytic network process (ANP), one of the multi-criteria decision making (MCDM) tools has been used to choose
one of the four alternative landfill sites for the city of Eskisehir, Turkey. For this purpose, Super Decision Software has
been used and benefit opportunity cost and risk (BOCR) analysis has been done to apply ANP. In BOCR analysis, each alternative
site has been evaluated in terms of its benefits, costs and risks; the opportunity cluster has been examined under the benefit
cluster. In this context, technical, economical and social assessments have been done for the site selection of sanitary landfill.
Also, results have been compared with analytic hierarchy process (AHP) which is another MCDM technique used in the study conducted
before. Finally, the current site has been determined as the most appropriate site in both methods. These methods have not
been commonly used in the discipline of environmental engineering but it is believed to be an important contribution for decision
makers. 相似文献
97.
98.
99.
Gürcan Büyüksalih Güven Koçak Hüseyin Topan Murat Oruç Aycan Marangoz 《The Photogrammetric Record》2005,20(110):130-146
SPOT 5 HRG Level 1A and 1B stereo scenes covering Zonguldak testfield in north-west Turkey have been analysed. They comprise the left and right image components with base to height ratio of 0·54. The pixel size on the ground is 5 m. The bundle orientation was executed by the PCI Geomatica V9.1.4 software package and resulted in 3D geopositioning to sub-pixel accuracies in each axis provided that at least six control points were used in the computation. Root mean square error (rmse) values and vectors of residual errors for Levels 1A and 1B are similar, even for different control and check point configurations. Based on the scene orientation, Level 1A and 1B digital elevation models (DEMs) of the testfield have been determined by automatic matching and validated by the reference DEM digitised from the 1:25 000 scale topographic maps, interferometric DEMs from Shuttle Radar Topography Mission (SRTM) X- and C-band SAR data and the GPS profiles measured along the main roads in the testfield. Although the accuracies of reference data-sets are too similar to the generated SPOT DEMs, these are the only high quality reference materials available in this area. Sub-pixel height accuracy was indicated by the comparison with profile points. However, they are in favourable locations where matching is always successful, so such a result may give a biased measure of the accuracy of the corresponding DEMs. 相似文献
100.
Murat Hatipoğlu Necdet Türk Steven C. Chamberlain A. Murat Akgün 《Mineralium Deposita》2010,45(2):201-205
Several m-thick, karst-unconformity-type metabauxite horizons in the İlbir Mountains of SW Turkey host open-space mineralization
of gem-quality diaspore (trademarked as zultanite), associated with muscovite, hematite, ilmenite, chloritoid, and younger
calcite. The hydrothermal-metamorphogenic mineralization occurs in fracture zones (veins and open structures) that crosscut
the metabauxite horizons, but does not extend into the marble host rocks. The white to dark gray marble sequence (over 2,000 m
in thickness) is of Cretaceous depositional age and was affected by Alpine (Paleogene) tectonometamorphism which caused the
hydrothermal remobilization of primary bauxite components into crosscutting structures. 相似文献