In this study, halloysite and sepiolite nanoclays were used to reinforce SBS modified bitumens. The nanoclays used are different from the materials in the literature and have properties such as easy to find, economical and available from local sources. The mixing parameters were determined before production process. The polymer additive SBS was added into base bitumen at 3% and 5%, the nanoclay additives were added into polymer modified bitumen at 2% and 4% ratios. The morphological structures were investigated under fluorescence microscope. Physical and rheological properties of the samples were compared. The phase separation cases were investigated by storage stability test. Furthermore, rutting performance of samples was measured with zero shear viscosity (ZSV) and multi stress creep recovery (MSCR) test methods.
{"title":"Preparation and Performance Testing of SBS Modified Bitumens Reinforced with Halloysite and Sepiolite Nanoclays","authors":"Dilay Uncu, A. Topal, Özgür Seydibeyoğlu","doi":"10.18400/tekderg.683568","DOIUrl":"https://doi.org/10.18400/tekderg.683568","url":null,"abstract":"In this study, halloysite and sepiolite nanoclays were used to reinforce SBS modified bitumens. The nanoclays used are different from the materials in the literature and have properties such as easy to find, economical and available from local sources. The mixing parameters were determined before production process. The polymer additive SBS was added into base bitumen at 3% and 5%, the nanoclay additives were added into polymer modified bitumen at 2% and 4% ratios. The morphological structures were investigated under fluorescence microscope. Physical and rheological properties of the samples were compared. The phase separation cases were investigated by storage stability test. Furthermore, rutting performance of samples was measured with zero shear viscosity (ZSV) and multi stress creep recovery (MSCR) test methods.","PeriodicalId":49442,"journal":{"name":"Teknik Dergi","volume":" ","pages":""},"PeriodicalIF":1.3,"publicationDate":"2022-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44999637","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 local scour around bridge piers is one of the main causes of bridge failures. In this study, scour hole dimensions around circular bridge piers were investigated under clear water scour conditions for various steady flow rates. The experiments were performed with four different bridge pier diameters and seven different flow rates by using uniform sediment with a median diameter of 1.63 mm and geometric standard deviation of 1.3. After each experiments the bathymetry of scour hole was determined. New empirical equations to estimate scour hole length, scour hole width and scour hole volume (V) are proposed by using experimental findings and experimental data available in the literature. The experimental results were also compared with those calculated using several empirical equations given by previous studies. Since there is a lack of data about scour hole dimensions, the experimental findings presented in this study are useful for the researchers investigating the local scour process, and have contributed to the few experimental data in the literature.
{"title":"Investigation of Local Scour Hole Dimensions around Circular Bridge Piers under Steady State Conditions","authors":"Ömer Yavuz Eski, A. Aksoy","doi":"10.18400/tekderg.704352","DOIUrl":"https://doi.org/10.18400/tekderg.704352","url":null,"abstract":"The local scour around bridge piers is one of the main causes of bridge failures. In this study, scour hole dimensions around circular bridge piers were investigated under clear water scour conditions for various steady flow rates. The experiments were performed with four different bridge pier diameters and seven different flow rates by using uniform sediment with a median diameter of 1.63 mm and geometric standard deviation of 1.3. After each experiments the bathymetry of scour hole was determined. New empirical equations to estimate scour hole length, scour hole width and scour hole volume (V) are proposed by using experimental findings and experimental data available in the literature. The experimental results were also compared with those calculated using several empirical equations given by previous studies. Since there is a lack of data about scour hole dimensions, the experimental findings presented in this study are useful for the researchers investigating the local scour process, and have contributed to the few experimental data in the literature.","PeriodicalId":49442,"journal":{"name":"Teknik Dergi","volume":" ","pages":""},"PeriodicalIF":1.3,"publicationDate":"2022-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43468186","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}
{"title":"Causal Relationships of Readability Risks in Construction Contracts","authors":"K. Koc, A. Gurgun","doi":"10.18400/tekderg.962928","DOIUrl":"https://doi.org/10.18400/tekderg.962928","url":null,"abstract":"","PeriodicalId":49442,"journal":{"name":"Teknik Dergi","volume":" ","pages":""},"PeriodicalIF":1.3,"publicationDate":"2022-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45573791","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}
As occupational accidents usually occur due to unsafe human behaviors in the construction industry, safety training is inevitably necessary for site personnel. On construction sites, various training methods including traditional and innovative ones, have been adopted to prevent accidents. In recent years, virtual safety training has been more prevalent because of providing highly engaging practice in a risk-free environment. Although these training tools have innumerable advantages in providing safety knowledge and awareness, they can be further improved. This study introduces a virtual safety training tool, V-SAFE.v2, to provide a more reliable and effective safety training for high-risk construction works. V-SAFE.v2 consists of three main modules; i) Training Module, ii) Testing Module 1, and iii) Testing Module 2. These modules are generated firstly to provide safety training for scaffolding and formwork activities and then to evaluate the safety performance of the trainees. An experiment was conducted with fifteen construction workers and ten engineers to measure the effectiveness of the training tool. The findings showed that V-SAFE.v2 is a reliable safety training tool for high-risk construction tasks as it supports collaboration, provides individual feedback, and repeatable practice. Also, the participants stated that V-SAFE.v2 has a great potential to reduce the falling from height accidents in the construction workplaces.
{"title":"Developing A Virtual Safety Training Tool for Scaffolding and Formwork Activities","authors":"G. Kazar, Semra Comu","doi":"10.18400/tekderg.711091","DOIUrl":"https://doi.org/10.18400/tekderg.711091","url":null,"abstract":"As occupational accidents usually occur due to unsafe human behaviors in the construction industry, safety training is inevitably necessary for site personnel. On construction sites, various training methods including traditional and innovative ones, have been adopted to prevent accidents. In recent years, virtual safety training has been more prevalent because of providing highly engaging practice in a risk-free environment. Although these training tools have innumerable advantages in providing safety knowledge and awareness, they can be further improved. This study introduces a virtual safety training tool, V-SAFE.v2, to provide a more reliable and effective safety training for high-risk construction works. V-SAFE.v2 consists of three main modules; i) Training Module, ii) Testing Module 1, and iii) Testing Module 2. These modules are generated firstly to provide safety training for scaffolding and formwork activities and then to evaluate the safety performance of the trainees. An experiment was conducted with fifteen construction workers and ten engineers to measure the effectiveness of the training tool. The findings showed that V-SAFE.v2 is a reliable safety training tool for high-risk construction tasks as it supports collaboration, provides individual feedback, and repeatable practice. Also, the participants stated that V-SAFE.v2 has a great potential to reduce the falling from height accidents in the construction workplaces.","PeriodicalId":49442,"journal":{"name":"Teknik Dergi","volume":"33 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2022-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41597236","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}
Developing countries like Turkey are trying to implement the Mechanistic-Empirical Pavement Design Guide (MEPDG). The implementation of this method requires comprehensive local data collection, evaluation, and, if necessary, a local calibration. The objective of this study is to prepare local data such as climate, traffic, and materials for evaluation and local calibration of MEPDG for Izmir City. For this purpose, the climate and traffic data were obtained, analysed, and converted to the MEPDG format. Besides, the bound and unbound pavement material properties were determined. Since some of the obtained local data like climate, vehicle classification, traffic growth factor, and axle load distribution cannot be directly used as design inputs, they were developed and converted to a suitable format to be used in the MEPDG. The output of this study can be used as design inputs for the evaluation and local calibration the MEPDG in Izmir and serves as a guide for data preparation for other parts of the country.
{"title":"Data Collection for Implementation of the Mechanistic-Empirical Pavement Design Guide (MEPDG) in Izmir, Turkey","authors":"Mohammad Razeq Shakhan, A. Topal, Burak Şengöz","doi":"10.18400/tekderg.651399","DOIUrl":"https://doi.org/10.18400/tekderg.651399","url":null,"abstract":"Developing countries like Turkey are trying to implement the Mechanistic-Empirical Pavement Design Guide (MEPDG). The implementation of this method requires comprehensive local data collection, evaluation, and, if necessary, a local calibration. The objective of this study is to prepare local data such as climate, traffic, and materials for evaluation and local calibration of MEPDG for Izmir City. For this purpose, the climate and traffic data were obtained, analysed, and converted to the MEPDG format. Besides, the bound and unbound pavement material properties were determined. Since some of the obtained local data like climate, vehicle classification, traffic growth factor, and axle load distribution cannot be directly used as design inputs, they were developed and converted to a suitable format to be used in the MEPDG. The output of this study can be used as design inputs for the evaluation and local calibration the MEPDG in Izmir and serves as a guide for data preparation for other parts of the country.","PeriodicalId":49442,"journal":{"name":"Teknik Dergi","volume":" ","pages":""},"PeriodicalIF":1.3,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45416358","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 paper presents the results from experimental study on the actual behavior of header end-plate connections. To better understand the hysteretic behavior of these connections in terms of the stiffness and the strength, sixteen specimens were considered and subjected to cyclic loads. The effect of some parameters such as thickness of the header end-plate, depth of the connection and the number of bolt rows on the behavior of header end-plate connections has been investigated by the help of experimental tests and finite element (FE) analyses. The moment-rotation relations of the connections governed by three parameters such as, initial stiffness, moment capacity and rotation capacity were obtained. Results revealed that the moment capacity increases with the increase in end-plate thickness and depth of connection. However, for the equal connection depth, increasing the number of bolt rows has not influenced the connection behavior remarkably.
{"title":"Experimental Study on the Behavior of Header End - Plate Connections under Cyclic Loading","authors":"A. Karasu, Cüneyt Vatansever","doi":"10.18400/tekderg.674889","DOIUrl":"https://doi.org/10.18400/tekderg.674889","url":null,"abstract":"This paper presents the results from experimental study on the actual behavior of header end-plate connections. To better understand the hysteretic behavior of these connections in terms of the stiffness and the strength, sixteen specimens were considered and subjected to cyclic loads. The effect of some parameters such as thickness of the header end-plate, depth of the connection and the number of bolt rows on the behavior of header end-plate connections has been investigated by the help of experimental tests and finite element (FE) analyses. The moment-rotation relations of the connections governed by three parameters such as, initial stiffness, moment capacity and rotation capacity were obtained. Results revealed that the moment capacity increases with the increase in end-plate thickness and depth of connection. However, for the equal connection depth, increasing the number of bolt rows has not influenced the connection behavior remarkably.","PeriodicalId":49442,"journal":{"name":"Teknik Dergi","volume":" ","pages":""},"PeriodicalIF":1.3,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48849844","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 was conducted in a deep well simulator used for typical irrigation studies. In this work, the changes in the pump flow rate, drawdown, noise level, and pump pressures were analyzed for three different gravel zone thicknesses used in the well. From the study, it was found that a high gravel zone thickness increased the well’s drawdown levels during pumping. For drawdown values of 40, 45, 50 and 55 m3 h–1, an increase in the gravel thickness by 10 cm increased these values by 2.92, 2.41, 2.38 and 2.37 times, respectively. When the gravel thickness was doubled (from 5 cm to 10 cm), the hydraulic conductivity decreased by about half and head loss doubled. As a result, gravel thickness directly affected the drawdown rate of the pump. It was shown that different drawdown values resulting due to different gravel thicknesses should be taken into consideration when placing the pump in a deep well.
{"title":"Effect of the Gravel Zone Thickness Created in the Deep Well Test Simulation on the Operating Characteristics of the Pump and Head Loss","authors":"N. Orhan, O. Özbek, A. Şeflek","doi":"10.18400/tekderg.691948","DOIUrl":"https://doi.org/10.18400/tekderg.691948","url":null,"abstract":"This study was conducted in a deep well simulator used for typical irrigation studies. In this work, the changes in the pump flow rate, drawdown, noise level, and pump pressures were analyzed for three different gravel zone thicknesses used in the well. From the study, it was found that a high gravel zone thickness increased the well’s drawdown levels during pumping. For drawdown values of 40, 45, 50 and 55 m3 h–1, an increase in the gravel thickness by 10 cm increased these values by 2.92, 2.41, 2.38 and 2.37 times, respectively. When the gravel thickness was doubled (from 5 cm to 10 cm), the hydraulic conductivity decreased by about half and head loss doubled. As a result, gravel thickness directly affected the drawdown rate of the pump. It was shown that different drawdown values resulting due to different gravel thicknesses should be taken into consideration when placing the pump in a deep well.","PeriodicalId":49442,"journal":{"name":"Teknik Dergi","volume":"32 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41850525","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}
Muhammet Çelik, Mehmet Tevfik Seferoğlu, M. Akpınar, M. Nasery, Ayşegül Güneş Seferoğlu
Transverse contraction joints are by far the most common type of joint in jointed plain concrete pavements. Early loading of contraction joints can create a weakened vertical plane and later grow as a full-depth crack. In this study, load transfer efficiency (LTE) of steel mesh reinforced transverse contraction joints were studied at accelerated pavement tests (APT). 3D finite element (FE) model of jointed plain concrete pavement (JPCP) was developed to study deflections and crack propagation in just under the joint of the concrete pavement. The APT tests were focused on the LTE values before and after the crack initiation under the contraction joint region. Experiments were performed on three slabs in which two of these slabs were prepared without reinforcement and one of them was reinforced with steel mesh. Data generated by APT was used for verification of crack propagation modeling in the finite element analysis. Steel mesh reinforced slab gave the lowest vertical deflections (51μm) and highest LTE (91.56%). The LTE value in the reinforced slab after 25,000 passes was 13.63% higher than the average of unreinforced slabs. The findings suggest that the load transfer efficiency was found to be a complex parameter and should be interpreted together with average displacement values when contraction joints are evaluated at early traffic loadings.
{"title":"Evaluation of Load-Transfer Efficiency of Steel Mesh Reinforced Contraction Joints in Concrete Pavement: Accelerated Pavement Test and FE Analysis","authors":"Muhammet Çelik, Mehmet Tevfik Seferoğlu, M. Akpınar, M. Nasery, Ayşegül Güneş Seferoğlu","doi":"10.18400/tekderg.643027","DOIUrl":"https://doi.org/10.18400/tekderg.643027","url":null,"abstract":"Transverse contraction joints are by far the most common type of joint in jointed plain concrete pavements. Early loading of contraction joints can create a weakened vertical plane and later grow as a full-depth crack. In this study, load transfer efficiency (LTE) of steel mesh reinforced transverse contraction joints were studied at accelerated pavement tests (APT). 3D finite element (FE) model of jointed plain concrete pavement (JPCP) was developed to study deflections and crack propagation in just under the joint of the concrete pavement. The APT tests were focused on the LTE values before and after the crack initiation under the contraction joint region. Experiments were performed on three slabs in which two of these slabs were prepared without reinforcement and one of them was reinforced with steel mesh. Data generated by APT was used for verification of crack propagation modeling in the finite element analysis. Steel mesh reinforced slab gave the lowest vertical deflections (51μm) and highest LTE (91.56%). The LTE value in the reinforced slab after 25,000 passes was 13.63% higher than the average of unreinforced slabs. The findings suggest that the load transfer efficiency was found to be a complex parameter and should be interpreted together with average displacement values when contraction joints are evaluated at early traffic loadings.","PeriodicalId":49442,"journal":{"name":"Teknik Dergi","volume":" ","pages":""},"PeriodicalIF":1.3,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47787618","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}
Calismada akilli ulasim sistemleri icin parametrik ve parametrik olmayan tahmin yontemlerin kisa zamanli trafik tahmin performanslari incelenmis ve tahmin degerlerinin sinyalize kavsaklarin devre suresine ve performansina olan etkisi arastirilmistir. Kavsakta gozlemlenen trafik verilerine bagli olarak gecikme surelerinin iyilestirmesi ve kavsak bekleme surelerinin azaltilarak, kavsak performans iyilestirmesi amaclanmistir. Calisma bolgesi olarak Denizli ilinde yer alan Mimar Sinan kavsagi secilmistir. Kavsagin yaklasim kollarinda bulunan sensorler yardimiyla elde edilen veriler, veri setleri olarak duzenlenmistir. Oto-regresif entegre hareketli ortalama (Auto-Regressive Integrated Moving Average-ARIMA) ve yapay sinir aglari (YSA) yontemleri ile kisa zamanli trafik tahminleri yapilmistir. Tahmin sonuclari Webster yontemi kullanilarak kavsak devre suresi optimizasyonu yapilmistir. Optimum devre suresi ve yesil sureleri hesaplandiktan sonra Webster gecikme metodu ile kavsak yaklasim kollarinin ve kavsak genelinin gecikme degerleri hem ARIMA yonteminden elde edilen hem de YSA yonteminden elde edilen tahmin sonuclari karsilastirilmistir. Kisa zamanli trafik tahmininde YSA yonteminin ARIMA yontemine gore daha basarili oldugu gorulmustur.
{"title":"Kısa Zamanlı Trafik Tahmini ile Devre Süresi Optimizasyonu ve Gecikme Analizi","authors":"Ravza Nur Yiğit, Soner Haldenbilen","doi":"10.18400/TEKDERG.713080","DOIUrl":"https://doi.org/10.18400/TEKDERG.713080","url":null,"abstract":"Calismada akilli ulasim sistemleri icin parametrik ve parametrik olmayan tahmin yontemlerin kisa zamanli trafik tahmin performanslari incelenmis ve tahmin degerlerinin sinyalize kavsaklarin devre suresine ve performansina olan etkisi arastirilmistir. Kavsakta gozlemlenen trafik verilerine bagli olarak gecikme surelerinin iyilestirmesi ve kavsak bekleme surelerinin azaltilarak, kavsak performans iyilestirmesi amaclanmistir. Calisma bolgesi olarak Denizli ilinde yer alan Mimar Sinan kavsagi secilmistir. Kavsagin yaklasim kollarinda bulunan sensorler yardimiyla elde edilen veriler, veri setleri olarak duzenlenmistir. Oto-regresif entegre hareketli ortalama (Auto-Regressive Integrated Moving Average-ARIMA) ve yapay sinir aglari (YSA) yontemleri ile kisa zamanli trafik tahminleri yapilmistir. Tahmin sonuclari Webster yontemi kullanilarak kavsak devre suresi optimizasyonu yapilmistir. Optimum devre suresi ve yesil sureleri hesaplandiktan sonra Webster gecikme metodu ile kavsak yaklasim kollarinin ve kavsak genelinin gecikme degerleri hem ARIMA yonteminden elde edilen hem de YSA yonteminden elde edilen tahmin sonuclari karsilastirilmistir. Kisa zamanli trafik tahmininde YSA yonteminin ARIMA yontemine gore daha basarili oldugu gorulmustur.","PeriodicalId":49442,"journal":{"name":"Teknik Dergi","volume":" ","pages":""},"PeriodicalIF":1.3,"publicationDate":"2021-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45967803","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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