A pre-design guide for cantilever retaining walls and a detail parametric study of such walls is presented here. Mathematical models based on statistical methods were improved for calculating safety factors of sliding, overturning, and slope stability of those walls. The harmony search algorithm (HSA)-a metaheuristic method-was employed to realize reasonable results of the pre-design guide from all distinct cases. Through the design algorithm, the optimal design was determined for varied soil types differently from suggestions of design codes. Thus, an optimal pre-design guide for safe and economic wall design was realized in a shorter time compared to the conventional method.
{"title":"Metaheuristics-based Pre-Design Guide for Cantilever Retaining Walls","authors":"Esra Uray, Ö. Tan, S. Çarbaş, I. Erkan","doi":"10.18400/tekderg.561956","DOIUrl":"https://doi.org/10.18400/tekderg.561956","url":null,"abstract":"A pre-design guide for cantilever retaining walls and a detail parametric study of such walls is presented here. Mathematical models based on statistical methods were improved for calculating safety factors of sliding, overturning, and slope stability of those walls. The harmony search algorithm (HSA)-a metaheuristic method-was employed to realize reasonable results of the pre-design guide from all distinct cases. Through the design algorithm, the optimal design was determined for varied soil types differently from suggestions of design codes. Thus, an optimal pre-design guide for safe and economic wall design was realized in a shorter time compared to the conventional method.","PeriodicalId":49442,"journal":{"name":"Teknik Dergi","volume":null,"pages":null},"PeriodicalIF":1.3,"publicationDate":"2021-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49126845","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this study, the correlation between the uniaxial compressive strength and unit side resistance of Gaziantep limestone was investigated experimentally for dry and fully saturated conditions. The results were compared with the methods given in the literature which correlate these two parameters. The linear correlations significantly overestimated the measured side resistance values for all tests while the non-linear methods generally overestimated the unit side resistance under fully saturated conditions but provided a reasonable estimation for dry samples. As a result, a linear correlation and non-linear correlation ranges for estimating the unit side resistance of such limestones were also suggested.
{"title":"An Experimental Study on Unit Side Resistance of Gaziantep Limestone","authors":"V. Kalpakcı, İslam Tabur","doi":"10.18400/tekderg.608631","DOIUrl":"https://doi.org/10.18400/tekderg.608631","url":null,"abstract":"In this study, the correlation between the uniaxial compressive strength and unit side resistance of Gaziantep limestone was investigated experimentally for dry and fully saturated conditions. The results were compared with the methods given in the literature which correlate these two parameters. The linear correlations significantly overestimated the measured side resistance values for all tests while the non-linear methods generally overestimated the unit side resistance under fully saturated conditions but provided a reasonable estimation for dry samples. As a result, a linear correlation and non-linear correlation ranges for estimating the unit side resistance of such limestones were also suggested.","PeriodicalId":49442,"journal":{"name":"Teknik Dergi","volume":null,"pages":null},"PeriodicalIF":1.3,"publicationDate":"2021-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45859748","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The standardized precipitation index (SPI) has been recognized as the standard index that should be used for quantifying and reporting meteorological drought. This study presents the implementation of the two-dimensional correlation method for determining the spatial and temporal variability of drought among the SPI series. The developed method was applied on 13 stations in Central Anatolia. The results show that the presented approach is capable of quantitatively assessing the differences in drought behaviour between stations. The paper also presents heatmaps as a new way of visualizing SPI series enabling detection of dry and wet periods.
{"title":"Detecting Drought Variability by using Two-Dimensional Correlation Analysis","authors":"F. Dikbaş, Ü. G. Bacanli","doi":"10.18400/tekderg.559195","DOIUrl":"https://doi.org/10.18400/tekderg.559195","url":null,"abstract":"The standardized precipitation index (SPI) has been recognized as the standard index that should be used for quantifying and reporting meteorological drought. This study presents the implementation of the two-dimensional correlation method for determining the spatial and temporal variability of drought among the SPI series. The developed method was applied on 13 stations in Central Anatolia. The results show that the presented approach is capable of quantitatively assessing the differences in drought behaviour between stations. The paper also presents heatmaps as a new way of visualizing SPI series enabling detection of dry and wet periods.","PeriodicalId":49442,"journal":{"name":"Teknik Dergi","volume":null,"pages":null},"PeriodicalIF":1.3,"publicationDate":"2021-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46785494","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this study, the characteristics of the flow in the region of swirling vortex are examined. The potential flow model based on the summing infinite number of spherical sinks along the vortex core is introduced to predict the flow field and the flow rate along the vortex axis. The flow towards the swirling vortex core has considerable effects on the radial velocity distribution within the ambient fluid flow region near the intake. The agreement between available test data relating to the radial velocity and the method introduced in this study is found to be satisfactory.
{"title":"Flow Rate along the Length of the Swirling Vortex Axis at an Intake","authors":"K. Taştan, N. Yıldırım","doi":"10.18400/tekderg.593595","DOIUrl":"https://doi.org/10.18400/tekderg.593595","url":null,"abstract":"In this study, the characteristics of the flow in the region of swirling vortex are examined. The potential flow model based on the summing infinite number of spherical sinks along the vortex core is introduced to predict the flow field and the flow rate along the vortex axis. The flow towards the swirling vortex core has considerable effects on the radial velocity distribution within the ambient fluid flow region near the intake. The agreement between available test data relating to the radial velocity and the method introduced in this study is found to be satisfactory.","PeriodicalId":49442,"journal":{"name":"Teknik Dergi","volume":null,"pages":null},"PeriodicalIF":1.3,"publicationDate":"2021-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44603614","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this study, the effect of channel-bed slope and non-prismatic converging channel on the discharge coefficient of labyrinth weirs is numerically investigated utilizing FLOW-3D model. Numerical simulation results show that modifying the labyrinth weir channel through both methods improves the discharge coefficient. Among the selected bed slopes and converging channel wall, the slope of β=4% and angle of θ=10° yielded the highest discharge coefficient. For a ratio HT/P=0.1, (HT: flow height, P: weir height) the discharge coefficient and discharge rate for bed slope and convergence angle case were 19.22%, 23.9% and 22.28%, 25.91% higher than for a conventional labyrinth weir in prismatic channel, respectively. Simultaneous application of a bed slope and convergence angle significantly increases the discharge coefficient and discharge value case were 28.64% and 30.42% higher than compared to the conventional case. Therefore, changing the bed slope and wall angle of the weir channel increases the discharge coefficient and in this type of weir and these design alterations should be considered in weir design.
{"title":"Effect of Different Channels on Discharge Coefficient of Labyrinth Weirs","authors":"R. Daneshfaraz, A. Ghaderi, J. Abraham, M. Torabi","doi":"10.18400/tekderg.629128","DOIUrl":"https://doi.org/10.18400/tekderg.629128","url":null,"abstract":"In this study, the effect of channel-bed slope and non-prismatic converging channel on the discharge coefficient of labyrinth weirs is numerically investigated utilizing FLOW-3D model. Numerical simulation results show that modifying the labyrinth weir channel through both methods improves the discharge coefficient. Among the selected bed slopes and converging channel wall, the slope of β=4% and angle of θ=10° yielded the highest discharge coefficient. For a ratio HT/P=0.1, (HT: flow height, P: weir height) the discharge coefficient and discharge rate for bed slope and convergence angle case were 19.22%, 23.9% and 22.28%, 25.91% higher than for a conventional labyrinth weir in prismatic channel, respectively. Simultaneous application of a bed slope and convergence angle significantly increases the discharge coefficient and discharge value case were 28.64% and 30.42% higher than compared to the conventional case. Therefore, changing the bed slope and wall angle of the weir channel increases the discharge coefficient and in this type of weir and these design alterations should be considered in weir design.","PeriodicalId":49442,"journal":{"name":"Teknik Dergi","volume":null,"pages":null},"PeriodicalIF":1.3,"publicationDate":"2021-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48563412","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Climate change and global warming are among the issues that humanity is most concerned about the future. The growing drought and flood risks that increase despite the taken measures have led to the adoption of an integrated understanding on the topic of water management in recent years. To manage the increased risk of drought and to make sustainable planning, the dimensions of drought should be known first. For this purpose, many drought indices have been developed. The Normalized Difference Vegetation Index (NDVI) and Vegetation Condition Index (VCI), which determined by remote sensing, are two of these. In this study, in which the agricultural drought was analyzed with vegetation indices by taking into consideration the historical drought archive, the Asi Basin was addressed. The data of the Asi Basin, which covers an area of 7800 km 2 and was obtained from the Moderate Resolution Imaging Spectroradiometer (MODIS) and Advanced Very High-Resolution Radiometer (AVHRR) satellites, was used in this study. With the satellites benefited in remote sensing and with the Coordination of Information on the Environment (CORINE), where the layers of vegetation were determined, agricultural and forest areas were evaluated separately. The vegetation indices, which change with the increase in temperature, have revealed the necessity of a long-term drought management for the Asi Basin. Result of the work pointed that NDVI index is more appropriated to the Asi Basin than the VCI index to monitor drought.
{"title":"Evaluation of Two Vegetation Indices (NDVI and VCI) Over Asi Basin in Turkey","authors":"M. Dikici, M. Aksel","doi":"10.18400/tekderg.590356","DOIUrl":"https://doi.org/10.18400/tekderg.590356","url":null,"abstract":"Climate change and global warming are among the issues that humanity is most concerned about the future. The growing drought and flood risks that increase despite the taken measures have led to the adoption of an integrated understanding on the topic of water management in recent years. To manage the increased risk of drought and to make sustainable planning, the dimensions of drought should be known first. For this purpose, many drought indices have been developed. The Normalized Difference Vegetation Index (NDVI) and Vegetation Condition Index (VCI), which determined by remote sensing, are two of these. In this study, in which the agricultural drought was analyzed with vegetation indices by taking into consideration the historical drought archive, the Asi Basin was addressed. The data of the Asi Basin, which covers an area of 7800 km 2 and was obtained from the Moderate Resolution Imaging Spectroradiometer (MODIS) and Advanced Very High-Resolution Radiometer (AVHRR) satellites, was used in this study. With the satellites benefited in remote sensing and with the Coordination of Information on the Environment (CORINE), where the layers of vegetation were determined, agricultural and forest areas were evaluated separately. The vegetation indices, which change with the increase in temperature, have revealed the necessity of a long-term drought management for the Asi Basin. Result of the work pointed that NDVI index is more appropriated to the Asi Basin than the VCI index to monitor drought.","PeriodicalId":49442,"journal":{"name":"Teknik Dergi","volume":null,"pages":null},"PeriodicalIF":1.3,"publicationDate":"2021-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42066249","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Stress fluctuations caused by stick-slip instabilities are frequently encountered in laboratory shear testings of granular materials. It is not common to observe stick-slips in angular-shaped granular assemblies, although rounded particles are more prone to this type of behaviour. This paper specifically concerns the deviatoric stress fluctuations in the shearing of coarse angular glass granules. A systematic experimental program comprising triaxial compression tests was realized to investigate the effects of particle size, confining pressure, and strain rate on the stick-slip mechanism. Particle size effect was examined by adopting three separate size distributions. In order to understand the influences of testing conditions on the stress fluctuations, the specimens were tested under four different confining pressures and by applying two distinct strain rates. The results showed that both the particle size and confining pressure greatly affected the stress fluctuations whereas the influence of strain rate was unclear.
{"title":"Stress Fluctuations in Triaxial Testing Of Angular Grains","authors":"Aydın Özbay, A. Cabalar","doi":"10.18400/tekderg.573637","DOIUrl":"https://doi.org/10.18400/tekderg.573637","url":null,"abstract":"Stress fluctuations caused by stick-slip instabilities are frequently encountered in laboratory shear testings of granular materials. It is not common to observe stick-slips in angular-shaped granular assemblies, although rounded particles are more prone to this type of behaviour. This paper specifically concerns the deviatoric stress fluctuations in the shearing of coarse angular glass granules. A systematic experimental program comprising triaxial compression tests was realized to investigate the effects of particle size, confining pressure, and strain rate on the stick-slip mechanism. Particle size effect was examined by adopting three separate size distributions. In order to understand the influences of testing conditions on the stress fluctuations, the specimens were tested under four different confining pressures and by applying two distinct strain rates. The results showed that both the particle size and confining pressure greatly affected the stress fluctuations whereas the influence of strain rate was unclear.","PeriodicalId":49442,"journal":{"name":"Teknik Dergi","volume":null,"pages":null},"PeriodicalIF":1.3,"publicationDate":"2021-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48928086","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Using the measured data on 15 laboratory models in USA, six models and one prototype in Turkey, the discharge coefficients ( C ’s) of radial-gated ogee spillways for various gate opennings and lake water surface elevations are computed. Comparison of these C ’s for 22 spillways with the ones given by Figure 9-31 of Design of Small Dams does not show close agreements. It is determined that C depends on both the angle Ɵ and the ratio d/H 1 , rather than Ɵ only where d and H 1 are the gate opening and the upstream head, and statistically significant regression equations are computed individually for each dam.
{"title":"Discharge Coefficients for Radial-Gated Ogee Spillways by Laboratory Data and by Design of Small Dams","authors":"T. Haktanir, Mohammed A. Khalaf","doi":"10.18400/tekderg.540640","DOIUrl":"https://doi.org/10.18400/tekderg.540640","url":null,"abstract":"Using the measured data on 15 laboratory models in USA, six models and one prototype in Turkey, the discharge coefficients ( C ’s) of radial-gated ogee spillways for various gate opennings and lake water surface elevations are computed. Comparison of these C ’s for 22 spillways with the ones given by Figure 9-31 of Design of Small Dams does not show close agreements. It is determined that C depends on both the angle Ɵ and the ratio d/H 1 , rather than Ɵ only where d and H 1 are the gate opening and the upstream head, and statistically significant regression equations are computed individually for each dam.","PeriodicalId":49442,"journal":{"name":"Teknik Dergi","volume":null,"pages":null},"PeriodicalIF":1.3,"publicationDate":"2021-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46961860","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This study presents developing procedures and verification of a new hybrid model, namely wavelet packet-genetic programming (WPGP) for short-term meteorological drought forecast. To this end, the multi-temporal standardized precipitation evapotranspiration index (SPEI) has been used as the drought quantifying parameter at two meteorological stations at Ankara province, Turkey. The new WPGP model comprises two main steps. In the first step, the wavelet packet, which is a generalization of the well-known wavelet transform, is used to decompose the SPEI series into deterministic and stochastic sub-signals. Then, classic genetic programming (GP) is applied to formulate the deterministic sub-signal considering its effective lags. To characterize the stochastic component, different theoretical probability distribution functions were assessed, and the best one was selected to integrate with the GP-evolved function. The efficiency of the new model was cross-validated with the first order autoregressive (AR1), GP, and random forest (RF) models developed as the benchmarks in the present study. The results showed that the WPGP is a robust model, superior to AR1 and RF, and significantly increases the predictive accuracy of the standalone GP model.
{"title":"Wavelet Packet-Genetic Programming: A New Model for Meteorological Drought Hindcasting","authors":"A. D. Mehr, M. Safari, Vahid Nourani","doi":"10.18400/tekderg.605453","DOIUrl":"https://doi.org/10.18400/tekderg.605453","url":null,"abstract":"This study presents developing procedures and verification of a new hybrid model, namely wavelet packet-genetic programming (WPGP) for short-term meteorological drought forecast. To this end, the multi-temporal standardized precipitation evapotranspiration index (SPEI) has been used as the drought quantifying parameter at two meteorological stations at Ankara province, Turkey. The new WPGP model comprises two main steps. In the first step, the wavelet packet, which is a generalization of the well-known wavelet transform, is used to decompose the SPEI series into deterministic and stochastic sub-signals. Then, classic genetic programming (GP) is applied to formulate the deterministic sub-signal considering its effective lags. To characterize the stochastic component, different theoretical probability distribution functions were assessed, and the best one was selected to integrate with the GP-evolved function. The efficiency of the new model was cross-validated with the first order autoregressive (AR1), GP, and random forest (RF) models developed as the benchmarks in the present study. The results showed that the WPGP is a robust model, superior to AR1 and RF, and significantly increases the predictive accuracy of the standalone GP model.","PeriodicalId":49442,"journal":{"name":"Teknik Dergi","volume":null,"pages":null},"PeriodicalIF":1.3,"publicationDate":"2021-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49081407","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Bu calismanin amaci, nanokil/polimer/bitum nanokompozitlerin uretim sureclerinin asfalt karisim performansi uzerindeki etkilerini arastirmaktir. Calismada nanokil (NC) ile stiren butadiyen stiren (SBS) elastomerik polimeri ve etilen vinil asetat (EVA) plastomerik polimerleri katilma onceligi degistirilerek bitume ilave edilmistir. Polimer modifiye asfalt nanokompozitlerle uretilen asfalt karisimlar dolayli cekme mukavemeti, modifiye Lottman yontemi, tekrarli sunme deneyi ve Fransiz tekerlek izi testleri ile degerlendirilmistir. EVA/nanokil/bitum nanokompozitler icin oncelikle EVA polimerinin eklenmesi durumunda su hasari, deformasyon ve catlama direnclerinde artis gozlenmistir. SBS’li nanokompozitler kullanildiginda once nanokil ilavesi genelde daha iyi sonuclar vermistir.
{"title":"Nanokil/Polimer/Bitüm Nanokompozit Hazırlama Yönteminin Asfalt Karışım Performansı Üzerindeki Etkilerinin Araştırılması","authors":"Erol Iskender, Atakan Aksoy","doi":"10.18400/tekderg.686346","DOIUrl":"https://doi.org/10.18400/tekderg.686346","url":null,"abstract":"Bu calismanin amaci, nanokil/polimer/bitum nanokompozitlerin uretim sureclerinin asfalt karisim performansi uzerindeki etkilerini arastirmaktir. Calismada nanokil (NC) ile stiren butadiyen stiren (SBS) elastomerik polimeri ve etilen vinil asetat (EVA) plastomerik polimerleri katilma onceligi degistirilerek bitume ilave edilmistir. Polimer modifiye asfalt nanokompozitlerle uretilen asfalt karisimlar dolayli cekme mukavemeti, modifiye Lottman yontemi, tekrarli sunme deneyi ve Fransiz tekerlek izi testleri ile degerlendirilmistir. EVA/nanokil/bitum nanokompozitler icin oncelikle EVA polimerinin eklenmesi durumunda su hasari, deformasyon ve catlama direnclerinde artis gozlenmistir. SBS’li nanokompozitler kullanildiginda once nanokil ilavesi genelde daha iyi sonuclar vermistir.","PeriodicalId":49442,"journal":{"name":"Teknik Dergi","volume":null,"pages":null},"PeriodicalIF":1.3,"publicationDate":"2021-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41427439","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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