Amirkabir University of Technology Amirkabir Journal of Civil Engineering 2588-297X 53 9 2021 11 22 Experimental and numerical investigation of scour around inclined pier group with sacrificial pile and collar Experimental and numerical investigation of scour around inclined pier group with sacrificial pile and collar 3607 3622 4048 10.22060/ceej.2020.17515.6587 FA Fatemeh Jafari Tabriz University Akram Abbaspour Tabriz University Hadi Arvanaghi Water Engineering Department, Faculty of Agriculture, University of Tabriz, Tabriz, Iran Ali Hosseinzade-Dalir Tabriz University 0000-0003-2359-3921 Journal Article 2020 02 09 The scour has been studied in hydraulic science for many years; due to its complexity, it has been the attention of hydraulic scientists. Hydraulic structures are situated as an obstacle in front of water flow that changed the flow pattern in their vicinity and causing the local scour around the structure. There are various methods to reduce local scour around the pier. In this research, sacrificial pile and collar were used to reduce the local scour around the inclined pier group. The results show that using the sacrificial pile in front of the inclined pier group, the effect of the inclined pier angle on the reduction of the scour is lower. So the difference between the percentage of scour reduction for the first and second inclined piers with the angle of 5 and 15 degrees is zero and in vertical pier is 1.4%. The use of three collars with a diameter of 4b in pier group with the distance of 4b between piers and presence of sacrificial pile in front of the first inclined pier in the distance of 3b compared to 2b show a greater scour depth reduction in front of the piers. In the numerical model, the use of an inclined pier group with the distance of 3b between piers and sacrificial pile with the distance of 2b shows lower turbulence intensity compared to distances of b and 3b. The scour has been studied in hydraulic science for many years; due to its complexity, it has been the attention of hydraulic scientists. Hydraulic structures are situated as an obstacle in front of water flow that changed the flow pattern in their vicinity and causing the local scour around the structure. There are various methods to reduce local scour around the pier. In this research, sacrificial pile and collar were used to reduce the local scour around the inclined pier group. The results show that using the sacrificial pile in front of the inclined pier group, the effect of the inclined pier angle on the reduction of the scour is lower. So the difference between the percentage of scour reduction for the first and second inclined piers with the angle of 5 and 15 degrees is zero and in vertical pier is 1.4%. The use of three collars with a diameter of 4b in pier group with the distance of 4b between piers and presence of sacrificial pile in front of the first inclined pier in the distance of 3b compared to 2b show a greater scour depth reduction in front of the piers. In the numerical model, the use of an inclined pier group with the distance of 3b between piers and sacrificial pile with the distance of 2b shows lower turbulence intensity compared to distances of b and 3b. collar Inclination angle of the pier Inclined pier group Local scour sacrificial pile https://ceej.aut.ac.ir/article_4048_5901fe6483310c89c35b54455f2a5557.pdf
Amirkabir University of Technology Amirkabir Journal of Civil Engineering 2588-297X 53 9 2021 11 22 An Analytical and Numerical Study on Effect of Thickness and Concrete Type of Panels on Behavior of Composite Steel Plate Shear Walls An Analytical and Numerical Study on Effect of Thickness and Concrete Type of Panels on Behavior of Composite Steel Plate Shear Walls 3623 3648 4202 10.22060/ceej.2020.17929.6713 FA Teymour Rahimi MSc, civil faculty, Semnan university, Semnan, iran Ali Kheyroddin Professor, Department of Civil Engineering, University of Semnan, Semnan, Iran. 0000-0001-7802-2013 Journal Article 2020 02 15 The composite steel plate shear wall (CSPSW) is an innovative lateral load-resisting system that is comprised of reinforced concrete (RC) panels attached to one or both sides of the system using shear connectors. Accordingly, in the CSPSW, the RC panels prevent buckling of the steel plate, and thus, the shear capacity of the plate improves by the shear yielding limit of the plate instead of tension in the direction of the diagonal tension field. Subsequently, this study is aimed to analytically and numerically investigate the effect of thickness and concrete type of panels on the behavior of the CSPSW. To this end, 27 numerical models of CSPSWs with varying thickness of steel plate and concrete panels as well as width-to-height (W/H) ratios of 0.75, 1 and 1.5 have been built using ABAQUS software and then, analyzed through the pushover analysis method. The results indicate that in all W/H ratios, the energy absorption of the models with a plate thickness of 6mm surpasses the others. Importantly, it was found that the response modification factor of the CSPSW is estimated to be 13.5. Lastly, a semi-empirical relationship was proposed to calculate the thickness of the RC panel based on that of the steel plate so that plate buckling could be prevented. The composite steel plate shear wall (CSPSW) is an innovative lateral load-resisting system that is comprised of reinforced concrete (RC) panels attached to one or both sides of the system using shear connectors. Accordingly, in the CSPSW, the RC panels prevent buckling of the steel plate, and thus, the shear capacity of the plate improves by the shear yielding limit of the plate instead of tension in the direction of the diagonal tension field. Subsequently, this study is aimed to analytically and numerically investigate the effect of thickness and concrete type of panels on the behavior of the CSPSW. To this end, 27 numerical models of CSPSWs with varying thickness of steel plate and concrete panels as well as width-to-height (W/H) ratios of 0.75, 1 and 1.5 have been built using ABAQUS software and then, analyzed through the pushover analysis method. The results indicate that in all W/H ratios, the energy absorption of the models with a plate thickness of 6mm surpasses the others. Importantly, it was found that the response modification factor of the CSPSW is estimated to be 13.5. Lastly, a semi-empirical relationship was proposed to calculate the thickness of the RC panel based on that of the steel plate so that plate buckling could be prevented. Composite Steel Plate Shear Wall (CSPSW) Plate Thickness Panel Thickness pushover analysis Modification Factor https://ceej.aut.ac.ir/article_4202_7d265aa7147bd3913fb84c7963a209d1.pdf
Amirkabir University of Technology Amirkabir Journal of Civil Engineering 2588-297X 53 9 2021 11 22 Travel Time Modelling of Urban Roads By Application of Coyote Optimization-based Machine Learning Method Travel Time Modelling of Urban Roads By Application of Coyote Optimization-based Machine Learning Method 3649 3664 3946 10.22060/ceej.2020.17991.6730 FA Amirhossein Fani Transportation Engineering, Department of Civil Engineering, Amirkabir University of Technology, Tehran, Iran Hamed Naseri Amir Kabir University of Technology Journal Article 2020 02 25 <span style="letter-spacing: .05pt;">Travel time prediction as an essential issue has been scrutinized in recent decades. To this end, various techniques are applied to estimate travel duration in dynamic networks and intelligent transportation systems. Accordingly, in this investigation, the prediction of travel time is considered by machine learning techniques. Initially, the experimental test is planned, and the travel time effective parameters are spotted. Subsequently, with the assistance of the floating car method, and My-tracks application, the data are collected in six elected roads. After data preparation, stop delay, grades, and the number of the lane are determined as the most effective travel time criteria. In this study, a novel machine learning technique based on the coyote optimization algorithm is introduced, and its precision is compared with five conventional regression models. Drawing on results, the accuracy of the coyote optimization algorithm-based machine learning technique is more than that of other prediction methods. The coefficient of determination of the introduced machine learning technique for training and testing data is equal to 0.746 and 0.724, respectively. Furthermore, coyote optimization algorithm-based machine learning estimates 73% of testing data with an error of fewer than 20 seconds. </span> <span style="letter-spacing: .05pt;">Travel time prediction as an essential issue has been scrutinized in recent decades. To this end, various techniques are applied to estimate travel duration in dynamic networks and intelligent transportation systems. Accordingly, in this investigation, the prediction of travel time is considered by machine learning techniques. Initially, the experimental test is planned, and the travel time effective parameters are spotted. Subsequently, with the assistance of the floating car method, and My-tracks application, the data are collected in six elected roads. After data preparation, stop delay, grades, and the number of the lane are determined as the most effective travel time criteria. In this study, a novel machine learning technique based on the coyote optimization algorithm is introduced, and its precision is compared with five conventional regression models. Drawing on results, the accuracy of the coyote optimization algorithm-based machine learning technique is more than that of other prediction methods. The coefficient of determination of the introduced machine learning technique for training and testing data is equal to 0.746 and 0.724, respectively. Furthermore, coyote optimization algorithm-based machine learning estimates 73% of testing data with an error of fewer than 20 seconds. </span> Travel time prediction Urban road Regression Machine learning Coyote optimization algorithm https://ceej.aut.ac.ir/article_3946_71a8b2ffe0b594a5c1b3c28090384fd7.pdf
Amirkabir University of Technology Amirkabir Journal of Civil Engineering 2588-297X 53 9 2021 11 22 Experimental Investigation of the Energy Dissipation and the Downstream Relative Depth of Pool in the Sloped Gabion Drop and the Sloped simple Drop Experimental Investigation of the Energy Dissipation and the Downstream Relative Depth of Pool in the Sloped Gabion Drop and the Sloped simple Drop 3665 3678 3953 10.22060/ceej.2020.18059.6751 FA Rasoul Daneshfaraz Professor, Department of Civil Engineering, Faculty of Engineering, University of Maragheh, Iran. 0000-0003-1012-8342 Mahdi Majedi Asl Assistant Professor, Department of Civil Engineering, Faculty of Engineering, University of Maragheh, Maragheh, Iran. Mohammad Bagherzadeh M.Sc. Student, Department of Civil Engineering, Faculty of Engineering, University of Maragheh, Maragheh, Iran. 0000-0002-5837-3331 Journal Article 2020 03 07 The present study investigates the behavior of hydraulic parameters of simple and sloped gabion drops experimentally. Therefore, 120 different experiments were carried out on both types of drops with three angles and two heights. The results showed that by increasing the relative critical depth in both models, the relative energy dissipation rate reduces but the relative downstream depth increase. Comparing the results for sloped gabion drops with sloped simple drops showed that the use of gabion structures with three angles and two heights increases the efficiency of average energy dissipation by 561% and the average downstream relative depth by 50.1% with regard to the simple drops. This results in a decrease in the erosion of the downstream bed of the structure and the length of the stilling basin. A comparison of the results shows that an increase in the angle decreases the efficiency of average energy dissipation and increases the average downstream relative depth. The results show that the variation in the angle of sloped gabion drops has an insignificant effect in comparison with the simple drops due to the physical properties and the complex hydraulic effects of the flow through the porous structure. Also, some equations were derived to estimate the relative energy dissipation rate and the downstream relative depth rate in the sloped gabion drops by using 80% percent of laboratory data, and the rest 20% of the data were used to test the equations with the goodness of fit criteria. The present study investigates the behavior of hydraulic parameters of simple and sloped gabion drops experimentally. Therefore, 120 different experiments were carried out on both types of drops with three angles and two heights. The results showed that by increasing the relative critical depth in both models, the relative energy dissipation rate reduces but the relative downstream depth increase. Comparing the results for sloped gabion drops with sloped simple drops showed that the use of gabion structures with three angles and two heights increases the efficiency of average energy dissipation by 561% and the average downstream relative depth by 50.1% with regard to the simple drops. This results in a decrease in the erosion of the downstream bed of the structure and the length of the stilling basin. A comparison of the results shows that an increase in the angle decreases the efficiency of average energy dissipation and increases the average downstream relative depth. The results show that the variation in the angle of sloped gabion drops has an insignificant effect in comparison with the simple drops due to the physical properties and the complex hydraulic effects of the flow through the porous structure. Also, some equations were derived to estimate the relative energy dissipation rate and the downstream relative depth rate in the sloped gabion drops by using 80% percent of laboratory data, and the rest 20% of the data were used to test the equations with the goodness of fit criteria. energy dissipation Downstream Relative Depth relative critical depth Angle of Inclined Drop Gabion https://ceej.aut.ac.ir/article_3953_b928fec5932bf2fddd2cc88c038b8ccb.pdf
Amirkabir University of Technology Amirkabir Journal of Civil Engineering 2588-297X 53 9 2021 11 22 Treatment of synthetic wastewater containing Cr(VI) using novel magnetic nanocomposite of Chitosan/EDTA/CeZnO under UV irradiation Treatment of synthetic wastewater containing Cr(VI) using novel magnetic nanocomposite of Chitosan/EDTA/CeZnO under UV irradiation 3679 3692 4114 10.22060/ceej.2020.18062.6753 FA Mohammad Delnavaz Civil engineering department, Faculty of Engineering, Civil Engineering Department, Kharazmi University 0000-0002-6843-2649 Masoumeh Sheikh Hosseini civil engineering department, Faculty of Engineering, Civil Engineering Department, Kharazmi University Alireza Shakeri Faculty of Chemistry, Tehran University Journal Article 2020 03 07 Because of the increasing use of chromium in various industries, water pollution with chromium has become a significant problem. Hexavalent chromium (Cr (VI)) is known as a toxic substance for aquatic organisms, animals and humans and as a carcinogen, so it is very important to treat this type of wastewater. In the present study, a new magnetic nanocomposite EDTA/Chitosan/CeZnO (MEC-CeZnO) was synthesized and used to remove heavy metal ions of Cr (VI) from an aqueous solution. The morphology, structure, and properties of the new MEC-CeZnO magnetic nanocomposite were identified by SEM, EDX, and XRD methods and the effect of various parameters such as initial pH, contact time and initial Cr (VI) concentration on system efficiency was investigated. The results showed that MEC-CeZnO nanoparticles with an average diameter of less than 45 nm, had the best performance of Cr (VI) regeneration at an input concentration of 10 mg/L, pH of 3 and retention time equal to 180 minutes. Also, process kinetic studies showed that the results of Cr (VI) reduction process follow the second-order kinetic model. Finally, the reusability of nanocomposites was tested in 5 cycles; the results showed high efficiency of 90% of nanocomposites in the reduction of metal ions. Because of the increasing use of chromium in various industries, water pollution with chromium has become a significant problem. Hexavalent chromium (Cr (VI)) is known as a toxic substance for aquatic organisms, animals and humans and as a carcinogen, so it is very important to treat this type of wastewater. In the present study, a new magnetic nanocomposite EDTA/Chitosan/CeZnO (MEC-CeZnO) was synthesized and used to remove heavy metal ions of Cr (VI) from an aqueous solution. The morphology, structure, and properties of the new MEC-CeZnO magnetic nanocomposite were identified by SEM, EDX, and XRD methods and the effect of various parameters such as initial pH, contact time and initial Cr (VI) concentration on system efficiency was investigated. The results showed that MEC-CeZnO nanoparticles with an average diameter of less than 45 nm, had the best performance of Cr (VI) regeneration at an input concentration of 10 mg/L, pH of 3 and retention time equal to 180 minutes. Also, process kinetic studies showed that the results of Cr (VI) reduction process follow the second-order kinetic model. Finally, the reusability of nanocomposites was tested in 5 cycles; the results showed high efficiency of 90% of nanocomposites in the reduction of metal ions. Magnetic chitosan Nanocomposite EDTA Hexavalent chromium Industrial wastewater https://ceej.aut.ac.ir/article_4114_ab24cd2b811ee48a416fc7a833d736a9.pdf
Amirkabir University of Technology Amirkabir Journal of Civil Engineering 2588-297X 53 9 2021 11 22 Durability of cementitious and geopolymer coating mortars against sulfuric acid attack. Durability of cementitious and geopolymer coating mortars against sulfuric acid attack. 3693 3708 4013 10.22060/ceej.2020.18068.6757 FA Faramarz Moodi Amirkabir University of Technology Aliakbar Ramezanianpor Amirkabir University of Technology Farhad Farhadian Amirkabir University of Technology Pouria Dashti Amirkabir University of Technology Journal Article 2020 03 07  Successive deterioration in concrete structures which is caused by the acid attack, has increased the need for substantial and costly repairs to deal with the destruction of concrete structures. Common devastation of water transfer tunnels is due to sulfuric acid attack. One of the ways of maintenance of such structures is to perform the protective coating of the cementitious and geopolymer coating mortars, in which the different features of this coating layer should be studied. In this study, the mechanical properties and durability of geopolymer and cementitious coating mortars containing granulated blast furnace slag and natural pozzolan have been compared. Five cementitious mortar mixtures were prepared with water to binder ratio of 0.32, binder content of 450 kg/m<sup>3, </sup>and replacement of Portland cement (PC) with 20 and 40% slag and natural pozzolan. 2 geopolymer mortar mixtures with KOH and NaOH as activator were designed. To evaluate their mechanical properties, Compressive strength and tensile adhesion strength were carried out. Also, in order to investigate their durability features against sulfuric acid attack, mortar specimens length Change, compressive strength loss, and weight loss were investigated. According to the results, the use of cement substitute materials (furnace slag and natural pozzolan) reduced the compressive strength by 25%, increased the adhesion strength by 50%, and reduced the length change, weight loss and compressive strength loss of the samples exposed to sulfuric acid. Also, the use of geopolymer mortars had the better performance than the control sample, so that more than 40% increase in compressive strength, about 150% increase in adhesion resistance and approximately 50% decrease in length change and weight loss and compressive strength loss compared to control sample in the sulfuric acid environment. In general, the test results show the proper performance of geopolymer repair mortars in aggressive acidic environments compared to cement-based mortars.  Successive deterioration in concrete structures which is caused by the acid attack, has increased the need for substantial and costly repairs to deal with the destruction of concrete structures. Common devastation of water transfer tunnels is due to sulfuric acid attack. One of the ways of maintenance of such structures is to perform the protective coating of the cementitious and geopolymer coating mortars, in which the different features of this coating layer should be studied. In this study, the mechanical properties and durability of geopolymer and cementitious coating mortars containing granulated blast furnace slag and natural pozzolan have been compared. Five cementitious mortar mixtures were prepared with water to binder ratio of 0.32, binder content of 450 kg/m<sup>3, </sup>and replacement of Portland cement (PC) with 20 and 40% slag and natural pozzolan. 2 geopolymer mortar mixtures with KOH and NaOH as activator were designed. To evaluate their mechanical properties, Compressive strength and tensile adhesion strength were carried out. Also, in order to investigate their durability features against sulfuric acid attack, mortar specimens length Change, compressive strength loss, and weight loss were investigated. According to the results, the use of cement substitute materials (furnace slag and natural pozzolan) reduced the compressive strength by 25%, increased the adhesion strength by 50%, and reduced the length change, weight loss and compressive strength loss of the samples exposed to sulfuric acid. Also, the use of geopolymer mortars had the better performance than the control sample, so that more than 40% increase in compressive strength, about 150% increase in adhesion resistance and approximately 50% decrease in length change and weight loss and compressive strength loss compared to control sample in the sulfuric acid environment. In general, the test results show the proper performance of geopolymer repair mortars in aggressive acidic environments compared to cement-based mortars. Durability Sulfuric Acid Attack Furnace slag Natural Pozzolan Geopolymer mortar https://ceej.aut.ac.ir/article_4013_fbfe5ba2ce3309f522c335e949435612.pdf
Amirkabir University of Technology Amirkabir Journal of Civil Engineering 2588-297X 53 9 2021 11 22 Analytical Comparison of Attitude Change to Integrated Management of Urban Water/Wastewater in the Development Plans of Iran Analytical Comparison of Attitude Change to Integrated Management of Urban Water/Wastewater in the Development Plans of Iran 3709 3730 3947 10.22060/ceej.2020.18080.6760 FA Seyed Ebrahim Nazlabadi Ph.D student of Environmental Engineering, Department of Civil and Environmental Engineering, Amirkabir University of Technology (Tehran Polytechnic), Tehran, Iran Reza Maknoon Associated professor, Department of Civil and Environmental Engineering, Amirkabir University of Technology (Tehran Polytechnic), Tehran, Iran Mohammad Reza Alavi Moghaddam Proffesor, Department of Civil and Environmental Engineering, Amirkabir University of Technology (Tehran Polytechnic), Tehran, Iran Journal Article 2020 03 10 <span style="letter-spacing: .05pt;">The main purpose of this study is an analytical comparison of attitude change to integrated management of urban water/wastewater in the development plans of Iran before and after the Islamic Revolution. The results indicate that there are four periods of changes in attitude towards this issue in Iran. The first period was initiated to launch planning thinking. In the second period, which lasted till before the Islamic Revolution, the planning system in Iran, after gaining experience, has undergone a dramatic change and some issues such as national coverage of the wastewater collection system, reliable water supply and minimum price of water, were mentioned in the development plans for the first time. In the end years of this period, planning in Iran was matured and all aspects of integrated management except water treatment had been considered. The third period came simultaneously with the revision of the constitution of Iran after the revolution. In this period, supported by macro policies after the mid-2000s, a period of excellence in the approach of integrated management of urban water and wastewater was created. Also, a macro roadmap in the planning system of Iran was developed. The fourth period of attitude changes began with the beginning of the second step of the revolution and will last until 2065. In this period, the "Islamic-Iranian Model of Progress", as an upstream framework of the macro policies and development plans, have a significant role in establishing an integrated urban water and wastewater management approach in future development plans.</span> <span style="letter-spacing: .05pt;">The main purpose of this study is an analytical comparison of attitude change to integrated management of urban water/wastewater in the development plans of Iran before and after the Islamic Revolution. The results indicate that there are four periods of changes in attitude towards this issue in Iran. The first period was initiated to launch planning thinking. In the second period, which lasted till before the Islamic Revolution, the planning system in Iran, after gaining experience, has undergone a dramatic change and some issues such as national coverage of the wastewater collection system, reliable water supply and minimum price of water, were mentioned in the development plans for the first time. In the end years of this period, planning in Iran was matured and all aspects of integrated management except water treatment had been considered. The third period came simultaneously with the revision of the constitution of Iran after the revolution. In this period, supported by macro policies after the mid-2000s, a period of excellence in the approach of integrated management of urban water and wastewater was created. Also, a macro roadmap in the planning system of Iran was developed. The fourth period of attitude changes began with the beginning of the second step of the revolution and will last until 2065. In this period, the "Islamic-Iranian Model of Progress", as an upstream framework of the macro policies and development plans, have a significant role in establishing an integrated urban water and wastewater management approach in future development plans.</span> Attitude Change Integrated Management Urban Water and Wastewater Development Plans Iran https://ceej.aut.ac.ir/article_3947_da4f21d00b1992e0b25f463b722dcc6a.pdf
Amirkabir University of Technology Amirkabir Journal of Civil Engineering 2588-297X 53 9 2021 11 22 Investigating the Effect of Active Tuned Mass Damper on the Endurance Time Diagram of Tall Buildings Investigating the Effect of Active Tuned Mass Damper on the Endurance Time Diagram of Tall Buildings 3731 3750 4041 10.22060/ceej.2020.18083.6761 FA Masoud Zabihi-Samani Iran University of Science and Technology: Tehran, Tehran 0000-0002-1330-165X Mohsen Ali Shayanfar The Centre of Excellence for Fundamental Studies in Structural Engineering, Iran University of Science and Technology, Tehran, Iran. Mohammad Reza Karbasi Civil Engineering faculty, Iran University of Science and Technology, Tehran, Iran Journal Article 2020 03 10 Nowadays, designing structures follow designs that are based on performance. Regarding the structures, designing based on performance requires dynamic, heavy and repetitive analyses. The endurance time method is a dynamic modern method based on the performance of the structure, which leads to the reduction of the number of structural analyses. In this method, the structure gets exposed to increasing acceleration functions that are getting more during time and then the structure`s seismic performance is evaluated using various demand parameters. In this article, though, using the endurance time method, the performance of a structure having an active mass damper was evaluated under endurance time acceleration functions of the ETA20e series. To this end, an 11-story structure having an active mass damper was modeled in MATLAB software using one of the fuzzy control methods. Having investigated the results of the endurance time diagram that had drawn the before and after statuses of the refinement process using active tuned mass damper, the efficiency of this system in reducing the interstory- drift and maximum final story drift was explored. Moreover, the results of endurance time under acceleration function of ETA20e series were compared with the time history analysis of 7 selected accelerograms. The results indicated that endurance time function could present an appropriate prediction in estimating the behavior of the structure under selected accelerograms. The results indicated the significant impact of adding mass dampers under increasing the endurance time of the building under investigation. Nowadays, designing structures follow designs that are based on performance. Regarding the structures, designing based on performance requires dynamic, heavy and repetitive analyses. The endurance time method is a dynamic modern method based on the performance of the structure, which leads to the reduction of the number of structural analyses. In this method, the structure gets exposed to increasing acceleration functions that are getting more during time and then the structure`s seismic performance is evaluated using various demand parameters. In this article, though, using the endurance time method, the performance of a structure having an active mass damper was evaluated under endurance time acceleration functions of the ETA20e series. To this end, an 11-story structure having an active mass damper was modeled in MATLAB software using one of the fuzzy control methods. Having investigated the results of the endurance time diagram that had drawn the before and after statuses of the refinement process using active tuned mass damper, the efficiency of this system in reducing the interstory- drift and maximum final story drift was explored. Moreover, the results of endurance time under acceleration function of ETA20e series were compared with the time history analysis of 7 selected accelerograms. The results indicated that endurance time function could present an appropriate prediction in estimating the behavior of the structure under selected accelerograms. The results indicated the significant impact of adding mass dampers under increasing the endurance time of the building under investigation. Performance Evaluation Endurance time Active Tuned Mass Damper Performance designing fuzzy control https://ceej.aut.ac.ir/article_4041_da0b566359c3862f20b5072c3d49bd0f.pdf
Amirkabir University of Technology Amirkabir Journal of Civil Engineering 2588-297X 53 9 2021 11 22 Wastewater treatment plants as a pathway for the release of microplastics into the environment: Investigation of sludge and treated effluent of Sari wastewater treatment plant Wastewater treatment plants as a pathway for the release of microplastics into the environment: Investigation of sludge and treated effluent of Sari wastewater treatment plant 3751 3762 3966 10.22060/ceej.2020.18097.6766 FA Somayye Sadat Alavian Petroody Department of Environmental Pollution, Institute of Environmental Sciences, Shahid Beheshti University, Tehran, Iran Seyed Hossein Hashemi Department of Environmental Technologies, Environmental Sciences Research Institute, Shahid Beheshti University 0000-0002-5351-3630 Journal Article 2020 03 11 Problems caused by the widespread presence of microplastics in the environment have attracted the attention of many researchers. Urban wastewater treatment plants are considered as one of the main releasing sources. In this study, Sari municipal wastewater treatment plant was investigated as one of the potential sources of contaminating aquatic ecosystems (Tajan River and the Caspian Sea) and terrestrial. The samples from effluent and sludge were taken with 3 replications, in April and June 2018. The effluent samples were passed through 500, 300 and 37 μm steel sieve. Organic materials in the sludge and effluent samples were digested using hydrogen peroxide. Then, microplastics were extracted based on the density separation technique by sodium iodide salt and analyzed using a stereomicroscope and micro-Raman. The average number of microplastics in the effluent was 423.4 per cubic meters, of which more than 77% were fiber and the dominant size of microplastics was 37-300 μm. Also, sewage sludge had an average of 128.8 microplastic per gram (dry weight), mostly in fiber form (87.5%). Examination of the microplastics structure showed that fibers were mainly polyester (effluent 40% and sludge 59%), whereas the majority of particles were polyethylene (effluent 73% and sludge 68%), which are mainly due to the wastewater of washing clothes and microbeads used in cosmetics. Therefore, considering the amount of microplastics present in the effluent and sludge, Sari wastewater treatment plant can be considered as one of the most important sources for the release of microplastics in the aquatic and terrestrial ecosystem in the north of the country. Problems caused by the widespread presence of microplastics in the environment have attracted the attention of many researchers. Urban wastewater treatment plants are considered as one of the main releasing sources. In this study, Sari municipal wastewater treatment plant was investigated as one of the potential sources of contaminating aquatic ecosystems (Tajan River and the Caspian Sea) and terrestrial. The samples from effluent and sludge were taken with 3 replications, in April and June 2018. The effluent samples were passed through 500, 300 and 37 μm steel sieve. Organic materials in the sludge and effluent samples were digested using hydrogen peroxide. Then, microplastics were extracted based on the density separation technique by sodium iodide salt and analyzed using a stereomicroscope and micro-Raman. The average number of microplastics in the effluent was 423.4 per cubic meters, of which more than 77% were fiber and the dominant size of microplastics was 37-300 μm. Also, sewage sludge had an average of 128.8 microplastic per gram (dry weight), mostly in fiber form (87.5%). Examination of the microplastics structure showed that fibers were mainly polyester (effluent 40% and sludge 59%), whereas the majority of particles were polyethylene (effluent 73% and sludge 68%), which are mainly due to the wastewater of washing clothes and microbeads used in cosmetics. Therefore, considering the amount of microplastics present in the effluent and sludge, Sari wastewater treatment plant can be considered as one of the most important sources for the release of microplastics in the aquatic and terrestrial ecosystem in the north of the country. Microplastic Effluent Sludge Wastewater treatment plant Mazandaran https://ceej.aut.ac.ir/article_3966_43d762ca733a839226415450b0dbf9d2.pdf
Amirkabir University of Technology Amirkabir Journal of Civil Engineering 2588-297X 53 9 2021 11 22 Direct displacement based design approach for steel moment frames equipped with nonlinear fluid viscous damper Direct displacement based design approach for steel moment frames equipped with nonlinear fluid viscous damper 3763 3784 4004 10.22060/ceej.2020.18103.6769 FA Mahsa Noruzvand Department of Civil Engineering, University of Mohaghegh Ardabili, Ardabil, Iran Kazem Shakeri Department of Civil Engineering, University of Mohaghegh Ardabili, Ardabil, Iran Journal Article 2020 03 13 The direct displacement-based design (DDBD) approach is one of the performance-based design methods that has been paid attention by designers and researchers because of its effective performance in the achievement of design performance level. In previous researches, the DDBD approach has been modified for the design of structures equipped with linear fluid viscous damper (FVD) by applying two different modification factors. These factors are applied because of higher mode effects and the difference between pseudo‐spectral velocity and spectral velocity. In this study, this approach is extended for nonlinear FVD and steel moment frames with different heights of 4, 8 and 12 stories are designed using this modified method to achieve life safety performance level under seismic hazard having a probability of occurrence 10% in 50 years. The design force of FVD is also considered as 30% of the design story shear at each story. To evaluate the design method performance, steel moment frames have been simulated in OpenSees and nonlinear time-history analysis has been performed under twenty earthquake records. The results show that average peak story drift becomes close to target drift with applying modification factors in the design process and the designed structures have achieved the desirable performance level. Therefore it can be concluded that the modified DDBD is an effective method for the design of steel moment frames equipped with nonlinear FVD. To evaluate the effect of FVD nonlinearity in design results, steel moment frames have also been designed using DDBD while have been controlled by linear FVD and a comparison has been conducted between design results. The results show that the design sections of structures equipped with linear and nonlinear FVDs are almost the same, whereas the nonlinear behavior of FVD has a significant effect on the design of the damping coefficient.<br />  The direct displacement-based design (DDBD) approach is one of the performance-based design methods that has been paid attention by designers and researchers because of its effective performance in the achievement of design performance level. In previous researches, the DDBD approach has been modified for the design of structures equipped with linear fluid viscous damper (FVD) by applying two different modification factors. These factors are applied because of higher mode effects and the difference between pseudo‐spectral velocity and spectral velocity. In this study, this approach is extended for nonlinear FVD and steel moment frames with different heights of 4, 8 and 12 stories are designed using this modified method to achieve life safety performance level under seismic hazard having a probability of occurrence 10% in 50 years. The design force of FVD is also considered as 30% of the design story shear at each story. To evaluate the design method performance, steel moment frames have been simulated in OpenSees and nonlinear time-history analysis has been performed under twenty earthquake records. The results show that average peak story drift becomes close to target drift with applying modification factors in the design process and the designed structures have achieved the desirable performance level. Therefore it can be concluded that the modified DDBD is an effective method for the design of steel moment frames equipped with nonlinear FVD. To evaluate the effect of FVD nonlinearity in design results, steel moment frames have also been designed using DDBD while have been controlled by linear FVD and a comparison has been conducted between design results. The results show that the design sections of structures equipped with linear and nonlinear FVDs are almost the same, whereas the nonlinear behavior of FVD has a significant effect on the design of the damping coefficient.<br />  Performance-based design direct displacement-based design Steel Moment Frame nonlinear fluid viscous damper target drift https://ceej.aut.ac.ir/article_4004_f8eb278a8bce873ef365b45e939da38a.pdf
Amirkabir University of Technology Amirkabir Journal of Civil Engineering 2588-297X 53 9 2021 11 22 Investigating the Effect of Acrylon Acrylonitrile Acrylate on the Fatigue Life of Asphalt Mixtures Investigating the Effect of Acrylon Acrylonitrile Acrylate on the Fatigue Life of Asphalt Mixtures 3785 3802 3939 10.22060/ceej.2020.18110.6770 FA Gholam Hossein Hamedi Department of Civil Engineering, Faculty of Engineering, University of Guilan 0000-0003-4421-3721 Ali Alipour Department of Civil Engineering, Islamic Azad University-Ahar Branch 0000-0002-3369-6978 Fariba Karimian Khosroshahi Islamic Azad University-Ilkhchi Branch Journal Article 2020 03 13 <span style="letter-spacing: .05pt;">Over time, with repeated loading, if the amount of strain or stress exceeds the strength of the asphalt mixtures, cracks will form on the surface and under the asphalt mixture layer. These cracks gradually develop as the number of loads increases and spreads to the asphalt body. Fatigue is one of the most important factors that reduce the life of asphalt pavements. One of the effective parameters in the occurrence of fatigue cracking is the properties of the bitumen used. According to previous studies, the use of nanomaterials and polymer additives has been considered by researchers in recent years. Due to the much higher cost of production or production of polymeric materials, the use of these materials in this research has been considered. One way to control this type of failure is to use bitumen, aggregate or asphalt mixers. Accordingly, in this study, the effect of using a polymer additive called acrylon acrylonitrile acrylate (ASA) as a bitumen modifier on the potential for fatigue cracking in asphalt mixtures has been investigated. Two types of aggregates, with different mineralogical properties, PG 64-16 as bitumen and ASA additive, in two different percentages of bitumen mass were the materials used in this study, which were tested at two temperatures and five different stress levels. To determine the percentage of optimal bitumen, the Marshall mixing design method has been used and to determine the fatigue life of asphalt mixtures, the indirect tensile fatigue test method has been used. The results of this study show that the use of polymer additives has increased the fatigue life of asphalt mixtures. The fatigue life of granite aggregate specimens was longer than that of limestone aggregates, but the increase in life resulting from the use of ASA increased the fatigue life of granite aggregate specimens. The increase in temperature and stress level, as expected, has reduced the fatigue life of asphalt mix samples, which is much lower in samples made of bitumen modified with polymeric materials than the samples. </span> <span style="letter-spacing: .05pt;">Over time, with repeated loading, if the amount of strain or stress exceeds the strength of the asphalt mixtures, cracks will form on the surface and under the asphalt mixture layer. These cracks gradually develop as the number of loads increases and spreads to the asphalt body. Fatigue is one of the most important factors that reduce the life of asphalt pavements. One of the effective parameters in the occurrence of fatigue cracking is the properties of the bitumen used. According to previous studies, the use of nanomaterials and polymer additives has been considered by researchers in recent years. Due to the much higher cost of production or production of polymeric materials, the use of these materials in this research has been considered. One way to control this type of failure is to use bitumen, aggregate or asphalt mixers. Accordingly, in this study, the effect of using a polymer additive called acrylon acrylonitrile acrylate (ASA) as a bitumen modifier on the potential for fatigue cracking in asphalt mixtures has been investigated. Two types of aggregates, with different mineralogical properties, PG 64-16 as bitumen and ASA additive, in two different percentages of bitumen mass were the materials used in this study, which were tested at two temperatures and five different stress levels. To determine the percentage of optimal bitumen, the Marshall mixing design method has been used and to determine the fatigue life of asphalt mixtures, the indirect tensile fatigue test method has been used. The results of this study show that the use of polymer additives has increased the fatigue life of asphalt mixtures. The fatigue life of granite aggregate specimens was longer than that of limestone aggregates, but the increase in life resulting from the use of ASA increased the fatigue life of granite aggregate specimens. The increase in temperature and stress level, as expected, has reduced the fatigue life of asphalt mix samples, which is much lower in samples made of bitumen modified with polymeric materials than the samples. </span> Asphalt mixtures Fatigue Cracking Bitumen modification Acrylon acrylonitrile acrylate Indirect tensile loading https://ceej.aut.ac.ir/article_3939_e5afb0f2dbc6d39b312d7406054cb4c6.pdf
Amirkabir University of Technology Amirkabir Journal of Civil Engineering 2588-297X 53 9 2021 11 22 Seismic response of the trapezoidal alluvial hill located on a circular cavity: Incident SH-wave. Seismic response of the trapezoidal alluvial hill located on a circular cavity: Incident SH-wave. 3803 3846 4775 10.22060/ceej.2020.18113.6772 FA Mehdi Panji Department of Civil Engineering, Islamic Azad University, Zanjan, Iran. 0000-0002-3240-7775 Saeed Mojtabazadeh-Hasanlouei Department of Civil Engineering, Zanjan Branch, Islamic Azad University, Zanjan, Iran. 0000-0001-8508-4837 Mohammad Habibivand Department of Civil Engineering, Zanjan Branch, Islamic Azad University, Zanjan, Iran. Journal Article 2020 03 15 A direct time-domain numerical approach named the half-plane boundary element method is proposed based on the half-space Green’s functions for seismic analysis of trapezoidal alluvial hill located on a circular cavity, subjected to propagating vertical incident SH-waves. To analyze the assumed model, a half plane time-domain Boundary Element Method (BEM) was used which can concentrate the meshes only around the boundary of desired features. First, the problem is decomposed into two parts including a pitted half-plane and a trapezoidal filled solid on the surface. Then, the influence coefficients of the matrices are obtained by applying the method to each part. By satisfying the boundary/continuity conditions on the interfaces, a coupled equation is formed to determine unknown boundary values in each time-step. After implementing the method in an advanced developed algorithm, its efficiency is investigated by solving some practical examples and compared with those of the published works. To complete the results, the sensitivity analysis was carried out to obtain the seismic response of hill by considering the key parameters including impedance and shape ratios. In the meantime, the effect of subsurface cavity on the amplification pattern of surface has been studied as well. The results showed that the impedance and shape ratios of the trapezoidal alluvial hill were very effective on the seismic response of surface. The results of the present study can be used by geotechnical engineers to completing and increasing the accuracy of existing codes around the subject of ground surface zonation in presence of different topographic features. A direct time-domain numerical approach named the half-plane boundary element method is proposed based on the half-space Green’s functions for seismic analysis of trapezoidal alluvial hill located on a circular cavity, subjected to propagating vertical incident SH-waves. To analyze the assumed model, a half plane time-domain Boundary Element Method (BEM) was used which can concentrate the meshes only around the boundary of desired features. First, the problem is decomposed into two parts including a pitted half-plane and a trapezoidal filled solid on the surface. Then, the influence coefficients of the matrices are obtained by applying the method to each part. By satisfying the boundary/continuity conditions on the interfaces, a coupled equation is formed to determine unknown boundary values in each time-step. After implementing the method in an advanced developed algorithm, its efficiency is investigated by solving some practical examples and compared with those of the published works. To complete the results, the sensitivity analysis was carried out to obtain the seismic response of hill by considering the key parameters including impedance and shape ratios. In the meantime, the effect of subsurface cavity on the amplification pattern of surface has been studied as well. The results showed that the impedance and shape ratios of the trapezoidal alluvial hill were very effective on the seismic response of surface. The results of the present study can be used by geotechnical engineers to completing and increasing the accuracy of existing codes around the subject of ground surface zonation in presence of different topographic features. Circular cavity Half-plane BEM SH-wave Trapezoidal hill Time-domain https://ceej.aut.ac.ir/article_4775_538a50fb36b97123adc3627cbdb223bf.pdf
Amirkabir University of Technology Amirkabir Journal of Civil Engineering 2588-297X 53 9 2021 11 22 A fuzzy approach for designing of subway lines, case study: development of the Tehran subway network A fuzzy approach for designing of subway lines, case study: development of the Tehran subway network 3847 3866 4256 10.22060/ceej.2021.18121.6774 FA Amir Reza Mahdavi Transportation Planning Department, Faculty of Civil and Environmental Engineering, Tarbiat Modares University, Tehran, Iran 0000-0001-7309-5002 Amirreza Mamdoohi Associate Professor, Faculty of Civil and Environmental Engineering, Tarbiat Modares University 0000-0002-5339-9807 Mahdieh Allahviranloo Groove School of Engineering, City College of New York, United States of America Journal Article 2020 03 15 Subway network design can be classified as one of the most challenging problems in transportation planning, where different deterministic or non-deterministic approaches have been utilized for optimal design. Non-deterministic methods, having fewer limitations and representing reality with its intrinsic uncertainty, have thus been the focus of less research. This paper incorporates concepts of fuzzy set theory into the optimal design of subway networks to the case of Tehran. Two binary mathematical programming models with different objective functions are developed. The first model maximizes the covered population while minimizing construction cost, whereas the second maximizes the ratio of the covered population to construction cost. These objective functions are modeled in both a fuzzy and a deterministic state. In the fuzzy model, we use a fuzzy penalty factor instead of edge length constraints and propose a Sugeno fuzzy inference system for calculating the covered population. Results indicate that the total length of designed lines with the linear and nonlinear fuzzy approach is equal to 139.3 km (477000 billion Iranian Rials) and 144.6 km (494000 billion Iranian Rials), respectively. Considering topology improvement per construction cost index, designed lines with the linear fuzzy model are better than the nonlinear fuzzy model. In comparison to the classic deterministic approach, the proposed fuzzy approach can improve topology improvement per construction cost index by 23 percent. Subway network design can be classified as one of the most challenging problems in transportation planning, where different deterministic or non-deterministic approaches have been utilized for optimal design. Non-deterministic methods, having fewer limitations and representing reality with its intrinsic uncertainty, have thus been the focus of less research. This paper incorporates concepts of fuzzy set theory into the optimal design of subway networks to the case of Tehran. Two binary mathematical programming models with different objective functions are developed. The first model maximizes the covered population while minimizing construction cost, whereas the second maximizes the ratio of the covered population to construction cost. These objective functions are modeled in both a fuzzy and a deterministic state. In the fuzzy model, we use a fuzzy penalty factor instead of edge length constraints and propose a Sugeno fuzzy inference system for calculating the covered population. Results indicate that the total length of designed lines with the linear and nonlinear fuzzy approach is equal to 139.3 km (477000 billion Iranian Rials) and 144.6 km (494000 billion Iranian Rials), respectively. Considering topology improvement per construction cost index, designed lines with the linear fuzzy model are better than the nonlinear fuzzy model. In comparison to the classic deterministic approach, the proposed fuzzy approach can improve topology improvement per construction cost index by 23 percent. Fuzzy mathematical programming Fuzzy factors Subway line design Non-deterministic approach Line locating https://ceej.aut.ac.ir/article_4256_ec99dd0bbd9458bc47d4b550b55aa1b2.pdf
Amirkabir University of Technology Amirkabir Journal of Civil Engineering 2588-297X 53 9 2021 11 22 Prediction of shear strength of deep beams of the reinforced concrete using weighted least squares support vector machine method Prediction of shear strength of deep beams of the reinforced concrete using weighted least squares support vector machine method 3867 3882 4167 10.22060/ceej.2020.18122.6775 FA Mohammad Reza Mohammadizadeh Department of Civil Engineering, Faculty of Technical and Engineering, University of Hormozgan Farnaz Esfandnia Department of Civil Engineering, Faculty of Technical and Engineering, University of Hormozgan, Bandar Abbas, Iran Journal Article 2020 03 16 The shear strength of deep reinforced concrete beams depends on the mechanical and geometrical properties of the beam. Accurate estimation of shear strength in deep reinforced concrete beams is one of the major issues in the design of engineering structures. However, some methods proposed to determine the shear strength in deep reinforced concrete beams do not have high accuracy. One method to accurately estimate shear strength is to use artificial intelligence (AI). Artificial intelligence has many different methods, one of which is the use of artificial intelligence-based on the support vector machine method. In this study, the weighted least squares support vector machine (WLS-SVM), which is a relatively new and efficient method for predicting the shear capacity of reinforced concrete beams, has been used. In this study, a database containing experimental results on deep reinforced concrete beams was first collected. Then, after determining the input and output parameters using a training process in WLS-SVM method and using a part of the collected data, a model was developed to predict the shear strength of deep reinforced concrete beams. In order to determine the accuracy of the WLS-SVM method, the results were compared with those obtained by other AI methods and different regulations. Statistical analysis showed that WLS-SVM has the best performance in terms of statistical evaluation parameters (R<sup>2</sup> = 0.9887, RMSE = 0.107, MAE = 0.478 and MAPE = 9.48%) compared to the other method. The shear strength of deep reinforced concrete beams depends on the mechanical and geometrical properties of the beam. Accurate estimation of shear strength in deep reinforced concrete beams is one of the major issues in the design of engineering structures. However, some methods proposed to determine the shear strength in deep reinforced concrete beams do not have high accuracy. One method to accurately estimate shear strength is to use artificial intelligence (AI). Artificial intelligence has many different methods, one of which is the use of artificial intelligence-based on the support vector machine method. In this study, the weighted least squares support vector machine (WLS-SVM), which is a relatively new and efficient method for predicting the shear capacity of reinforced concrete beams, has been used. In this study, a database containing experimental results on deep reinforced concrete beams was first collected. Then, after determining the input and output parameters using a training process in WLS-SVM method and using a part of the collected data, a model was developed to predict the shear strength of deep reinforced concrete beams. In order to determine the accuracy of the WLS-SVM method, the results were compared with those obtained by other AI methods and different regulations. Statistical analysis showed that WLS-SVM has the best performance in terms of statistical evaluation parameters (R<sup>2</sup> = 0.9887, RMSE = 0.107, MAE = 0.478 and MAPE = 9.48%) compared to the other method. Deep beam of reinforced concrete Shear Strength Artificial Intelligence Weighted least squares support vector machine https://ceej.aut.ac.ir/article_4167_e038453073d221a4f32d0bab94ca7cee.pdf
Amirkabir University of Technology Amirkabir Journal of Civil Engineering 2588-297X 53 9 2021 11 22 Numerical simulation of flow velocity around single and twin bridge piers with different arrangements using the Fluent model Numerical simulation of flow velocity around single and twin bridge piers with different arrangements using the Fluent model 3883 3896 4065 10.22060/ceej.2020.18136.6777 FA Zahra Behrouzi Water Engineering Department, Shiraz University Hossein Hamidifar Water Engineering Department, Shiraz University Mohammad Ali Zomorodian Shiraz University Journal Article 2020 03 18 Flow structure around the bridge pier is a very complicated phenomenon. Due to the special geometric and structural conditions in some cases, it is required that the piers be placed in pairs next to each other with special arrangements, which leads to a more complex flow structure around the piers. In this study, the variations of the flow velocity and turbulent kinetic energy around single and twin bridge piers with a circular cross-section are simulated using the Fluent model. The twin piers are placed in three configurations, including tandem, side-by-side, and at inclined with the flow direction. The three-dimensional components of flow velocity, streamlines, and velocity contours have been investigated for both single and twin piers. By comparing the longitudinal velocity between measured and simulated conditions in two selected cross-sections, the average error for the single tandem piers was 7.3% and 3.54%, respectively. Also, the longitudinal velocity in the tandem, side-by-side and inclined piers has decreased by 2.34% and 9.27% ​​and increased by 87.8%, respectively, compared to the single pier conditions. In general, due to the minimum values of turbulent velocity and kinetic energy, the side-by-side model is recommended as the most appropriate arrangement of the piers with respect to the flow direction. Flow structure around the bridge pier is a very complicated phenomenon. Due to the special geometric and structural conditions in some cases, it is required that the piers be placed in pairs next to each other with special arrangements, which leads to a more complex flow structure around the piers. In this study, the variations of the flow velocity and turbulent kinetic energy around single and twin bridge piers with a circular cross-section are simulated using the Fluent model. The twin piers are placed in three configurations, including tandem, side-by-side, and at inclined with the flow direction. The three-dimensional components of flow velocity, streamlines, and velocity contours have been investigated for both single and twin piers. By comparing the longitudinal velocity between measured and simulated conditions in two selected cross-sections, the average error for the single tandem piers was 7.3% and 3.54%, respectively. Also, the longitudinal velocity in the tandem, side-by-side and inclined piers has decreased by 2.34% and 9.27% ​​and increased by 87.8%, respectively, compared to the single pier conditions. In general, due to the minimum values of turbulent velocity and kinetic energy, the side-by-side model is recommended as the most appropriate arrangement of the piers with respect to the flow direction. Flow pattern velocity bridge pier Simulation Fluent https://ceej.aut.ac.ir/article_4065_5463b514e21fbd3fec3772fba142a46e.pdf
Amirkabir University of Technology Amirkabir Journal of Civil Engineering 2588-297X 53 9 2021 11 22 Determining the capability of artificial intelligence in estimating energy dissipation of skimming flow regime at stepped spillways Determining the capability of artificial intelligence in estimating energy dissipation of skimming flow regime at stepped spillways 3897 3912 4115 10.22060/ceej.2020.18156.6783 FA Arash Jael assistante proffessor, Agriculture Department, Payame Noor University, Iran 0000-0003-0837-2485 Mohammad Rashki Ghaleh Nou Ph.D Student- Hydraulic structures- Dep. of Civil Engineering- University of Sistan and Balouchestan- Zahedan 0000-0002-3923-0511 Masih Zolghadr Assitant Professor, Dept. Of Water Sciences Engineering, Faculty of Agriculture, Jahrom University, Fars, Iran Journal Article 2020 03 23 Energy dissipation in stepped spillways is one of the primary goals of such structures. In this study, the accuracy of the Artificial Neural Network (ANN), Adaptive Fuzzy Neural Inference System based on the trained Firefly Algorithm utilized for optimization (ANFIS-FA) and the Gene Expression Programming method (GEP), in estimating the energy loss of skimming flow regime over stepped spillways was studied. Also, by performing sensitivity analysis, the importance of input parameters in predicting energy loss for each of the three mentioned methods was investigated. For this purpose, 154 series of experimental data were considered. The input parameters for each method include hydraulic jump, Froude number, Drop number, number of steps, Pseudo bottom slope and the ratio of the critical depth to the height of each step. The results show that all three methods had a higher ability to predict energy loss compared to classical methods based on conventional regression methods. The accuracy of the ANFIS-FA method is slightly higher than the GEP method. The accuracy of the ANN is slightly lower than mentioned methods. However, the highest accuracy is related to the multilayer perceptron ANN with 3 hidden layers with 12, 8 and 7 nodes in each layer, respectively. In all three methods, the most effective parameter was found to be the drop number and the least effective parameter was the bottom slope. Energy dissipation in stepped spillways is one of the primary goals of such structures. In this study, the accuracy of the Artificial Neural Network (ANN), Adaptive Fuzzy Neural Inference System based on the trained Firefly Algorithm utilized for optimization (ANFIS-FA) and the Gene Expression Programming method (GEP), in estimating the energy loss of skimming flow regime over stepped spillways was studied. Also, by performing sensitivity analysis, the importance of input parameters in predicting energy loss for each of the three mentioned methods was investigated. For this purpose, 154 series of experimental data were considered. The input parameters for each method include hydraulic jump, Froude number, Drop number, number of steps, Pseudo bottom slope and the ratio of the critical depth to the height of each step. The results show that all three methods had a higher ability to predict energy loss compared to classical methods based on conventional regression methods. The accuracy of the ANFIS-FA method is slightly higher than the GEP method. The accuracy of the ANN is slightly lower than mentioned methods. However, the highest accuracy is related to the multilayer perceptron ANN with 3 hidden layers with 12, 8 and 7 nodes in each layer, respectively. In all three methods, the most effective parameter was found to be the drop number and the least effective parameter was the bottom slope. ANFIS-FA ANN energy dissipation GEP skimming flow stepped spillway https://ceej.aut.ac.ir/article_4115_a5ff5d4b0a0d7b3e4d64147037d8c344.pdf
Amirkabir University of Technology Amirkabir Journal of Civil Engineering 2588-297X 53 9 2021 11 22 Analysis of seepage in the conditions of increased reservoir capacity by raising the spillway level (Case study: Kamal-Saleh earth dam) Analysis of seepage in the conditions of increased reservoir capacity by raising the spillway level (Case study: Kamal-Saleh earth dam) 3913 3932 4005 10.22060/ceej.2020.18161.6786 FA Sanaz Aalimohammadi Piranshahi Arak university Nazanin Shahkarami Department of Civil, Faculty of Engineering, Arak University, Arak, Iran Hosein Asadi Deputy of Planning and Development, Regional Water Company of Markazi, Arak, Iran Journal Article 2020 03 26 Seepage is one of the main threats to the stability of the earth dam, which can weaken the dam structure and cause piping, washing the earth dam materials inside the body or foundation and eventually its failure. In this study, seepage analysis of Kamal-Saleh earth dam was performed using Seep/W software under three conditions of steady-state, rapid drawdown and end of construction for the current dam as well as for increased spillway level in stable seepage condition. The effect of increasing the height of spillway on the seepage rate inside the body and foundation of the dam, hydraulic gradient and phreatic surface was investigated. To evaluate the dam behavior in the conditions of increasing reservoir capacity, seepage analysis was performed for the current level and increased levels of spillway by one-meter intervals. According to the software results, the dam was safe against seepage in the current spillway level in every three conditions and provided the required factors of safety. In the conditions of increased spillway level, the amounts of seepage and the hydraulic gradients increased and the factors of safety against boiling decreased in a way that by increasing the dam spillway level equal to 4 meters, the seepage through the dam body and foundation increased 85% and the safety factor against boiling decreased 4.5% but in all these conditions, the dam was safe against boiling. In the current and increased levels of the spillway, there are the appropriate similarity of phreatic lines produced by the selected analytical method and Seep/W.  The most similarity is seen in the upstream shell and core and the maximum difference is seen in the phreatic line intersection with the downstream slope of the dam. Seepage is one of the main threats to the stability of the earth dam, which can weaken the dam structure and cause piping, washing the earth dam materials inside the body or foundation and eventually its failure. In this study, seepage analysis of Kamal-Saleh earth dam was performed using Seep/W software under three conditions of steady-state, rapid drawdown and end of construction for the current dam as well as for increased spillway level in stable seepage condition. The effect of increasing the height of spillway on the seepage rate inside the body and foundation of the dam, hydraulic gradient and phreatic surface was investigated. To evaluate the dam behavior in the conditions of increasing reservoir capacity, seepage analysis was performed for the current level and increased levels of spillway by one-meter intervals. According to the software results, the dam was safe against seepage in the current spillway level in every three conditions and provided the required factors of safety. In the conditions of increased spillway level, the amounts of seepage and the hydraulic gradients increased and the factors of safety against boiling decreased in a way that by increasing the dam spillway level equal to 4 meters, the seepage through the dam body and foundation increased 85% and the safety factor against boiling decreased 4.5% but in all these conditions, the dam was safe against boiling. In the current and increased levels of the spillway, there are the appropriate similarity of phreatic lines produced by the selected analytical method and Seep/W.  The most similarity is seen in the upstream shell and core and the maximum difference is seen in the phreatic line intersection with the downstream slope of the dam. Seepage analysis Kamal-Saleh earth dam phreatic surface storage capacity increase seep/w https://ceej.aut.ac.ir/article_4005_f23b3df742bb9fbf6bbf30a05150ac19.pdf
Amirkabir University of Technology Amirkabir Journal of Civil Engineering 2588-297X 53 9 2021 11 22 Presentation of a New Method in Mathematical Modeling of Pollutant Transport in Rivers with Storage Zones Presentation of a New Method in Mathematical Modeling of Pollutant Transport in Rivers with Storage Zones 3933 3946 4108 10.22060/ceej.2020.18146.6787 FA Mojtaba Faraji Msc. Graduate of Water Structures, Faculty of Agriculture, Tarbiat Modares University, Tehran, Iran, Jamal M. V. Samani Professor, Department of Water Structures, Faculty of Agriculture, Tarbiat Modares University,Tehran, Iran Journal Article 2020 03 26 Prediction of pollutants transport in water resources is of particular importance in the management and prevention of their pollution. The heterogeneity and non-uniformity in the morphology throughout rivers which is known as the storage area, will make changes in the uniform transport of pollutants to downstream. Storage areas along rivers are actually places around the river where flow velocity in these places is significantly slower than the river’s flow velocity and are also known as dead zones. The presence of these places in rivers makes it difficult to apply the classic pollutant transport equation for them. For a more accurate simulation of the pollutant transport in natural rivers containing storage zones, some improvements should be made to the classic advection-dispersion equation. In this study, a new approach is presented by considering nonlinear flux dispersion and applying storage zones. In order for verification and validation of the proposed model, two series of hypothetical and real data examples have been used. Based on the measured results, the model outputs have acceptable adaptation with observational data and show that the proposed model is an accurate and acceptable model in the simulation of dissolved pollutant transport in rivers with storage zones. According to the obtained concentration-time curves, it can be concluded that the proposed model can model any type of storage area with any amount of area. Also, this model is applicable for all rivers with and without storage area and it is more superior in comparison with other similar models in terms of the number of parameters (considering merely one parameter) and simplicity in physical interpretation; and can be an appropriate alternative instead of the classic pollutant transport model in these type of rivers. Prediction of pollutants transport in water resources is of particular importance in the management and prevention of their pollution. The heterogeneity and non-uniformity in the morphology throughout rivers which is known as the storage area, will make changes in the uniform transport of pollutants to downstream. Storage areas along rivers are actually places around the river where flow velocity in these places is significantly slower than the river’s flow velocity and are also known as dead zones. The presence of these places in rivers makes it difficult to apply the classic pollutant transport equation for them. For a more accurate simulation of the pollutant transport in natural rivers containing storage zones, some improvements should be made to the classic advection-dispersion equation. In this study, a new approach is presented by considering nonlinear flux dispersion and applying storage zones. In order for verification and validation of the proposed model, two series of hypothetical and real data examples have been used. Based on the measured results, the model outputs have acceptable adaptation with observational data and show that the proposed model is an accurate and acceptable model in the simulation of dissolved pollutant transport in rivers with storage zones. According to the obtained concentration-time curves, it can be concluded that the proposed model can model any type of storage area with any amount of area. Also, this model is applicable for all rivers with and without storage area and it is more superior in comparison with other similar models in terms of the number of parameters (considering merely one parameter) and simplicity in physical interpretation; and can be an appropriate alternative instead of the classic pollutant transport model in these type of rivers. advection-dispersion equation Storage zone Non-linear Flux Dead Zone Dispersion Flux https://ceej.aut.ac.ir/article_4108_b2b7c555125ecacf4bb7678d9dc39a21.pdf
Amirkabir University of Technology Amirkabir Journal of Civil Engineering 2588-297X 53 9 2021 11 22 Applying Genetic Algorithm to estimate the behavior factor of EBF steel frames under pulse-type near-fault earthquakes, performance level approach Applying Genetic Algorithm to estimate the behavior factor of EBF steel frames under pulse-type near-fault earthquakes, performance level approach 3947 3966 3990 10.22060/ceej.2020.18162.6788 FA Seyed Abdonnabi Razavi Department of Civil Engineering, Islamic Azad University, Ahvaz branch, Ahvaz, Iran 0000-0003-0269-1047 Navid Siahpolo Assistant professor and head of higher education office/ACECR Institute for higher education-Khuzestan branch-Ahwaz Mehdi Mahdavi Adeli Assistant Professor, Department of Civil Engineering, Islamic Azad University, Ahvaz branch, Ahvaz, Iran Journal Article 2020 03 27 The most important feature of the behavior factor is that it allows the structural designer to be able to evaluate the structural seismic demand, using an elastic analysis based on force-based principles quickly. In seismic codes such as the 2800 Standard, this coefficient is merely dependent on the type of lateral resistance system and is introduced with a fixed number. However, there is a relationship between the behavior factor, ductility (performance level), structural geometric properties, and type of earthquake (near and far). The main purpose of this paper is to establish an accurate correlation between the geometrical characteristics of the structure, performance level and the behavior factor in eccentrically steel frames under earthquakes near-fault. For this purpose, a genetic algorithm is used. Initially, a wide database consisting of 12960 data with 3-, 6-, 9-, 12-, 15- and 20- stories, 3 column stiffness types, and 3 brace slenderness types were designed and analyzed under 20 pulse-type near-fault earthquakes for 4 different performance levels. To generate the proposed relation, 7533 training data in the form of genetic optimization algorithm were used. To validate the proposed relationship, 2515 test data were used to calculate the mean squared error of the relationship in the fitness function. The results of the correlation show accuracy of the proposed coefficients. Also, the comparison of the response of maximum inelastic displacement of 5stories EBF from the proposed correlation and the mean inelastic time history analysis confirms the accuracy of the estimated relationship. The most important feature of the behavior factor is that it allows the structural designer to be able to evaluate the structural seismic demand, using an elastic analysis based on force-based principles quickly. In seismic codes such as the 2800 Standard, this coefficient is merely dependent on the type of lateral resistance system and is introduced with a fixed number. However, there is a relationship between the behavior factor, ductility (performance level), structural geometric properties, and type of earthquake (near and far). The main purpose of this paper is to establish an accurate correlation between the geometrical characteristics of the structure, performance level and the behavior factor in eccentrically steel frames under earthquakes near-fault. For this purpose, a genetic algorithm is used. Initially, a wide database consisting of 12960 data with 3-, 6-, 9-, 12-, 15- and 20- stories, 3 column stiffness types, and 3 brace slenderness types were designed and analyzed under 20 pulse-type near-fault earthquakes for 4 different performance levels. To generate the proposed relation, 7533 training data in the form of genetic optimization algorithm were used. To validate the proposed relationship, 2515 test data were used to calculate the mean squared error of the relationship in the fitness function. The results of the correlation show accuracy of the proposed coefficients. Also, the comparison of the response of maximum inelastic displacement of 5stories EBF from the proposed correlation and the mean inelastic time history analysis confirms the accuracy of the estimated relationship. genetic algorithm behavior factor Eccentric braced frame Pulse-type near-fault earthquake Performance level https://ceej.aut.ac.ir/article_3990_7612936dcc85282c6fa4dd9d4ffe57f1.pdf
Amirkabir University of Technology Amirkabir Journal of Civil Engineering 2588-297X 53 9 2021 11 22 Simulation of behavior of the Kabudval Dam during construction with 3D numerical modeling Simulation of behavior of the Kabudval Dam during construction with 3D numerical modeling 3967 3984 4049 10.22060/ceej.2020.18172.6790 FA Fazin Salmasi Department of Water Engineering, Faculty of Agriculture, University of Tabriz, Tabriz, Iran 0000-0002-1627-8598 Hosein Hakimi Khansar Department of Water Engineering, Faculty of Agriculture, University of Tabriz, Tabriz, Iran Journal Article 2020 03 28 Accurate prediction of pore water pressure, settlement, soil stress and pore water pressure coefficient (R<sub>u</sub>) in the body of earth dams during construction is one of the necessary measures in the management of earth dam stability. Because the behavior of the earth dams is nonlinear, it is necessary to use finite element methods and suitable soil behavior models. In the present study, which is a case study, a three-dimensional numerical simulation was performed using the Plaxis software for the Kabudval Dam located in Golestan province, Iran. The values obtained from the numerical simulation were compared with the corresponding measured values using the dam instruments. Calibration was carried out using the back analysis method (BAM) and some dam geotechnical parameters were corrected based on BAM. The results showed that the hardening soil (HS) model with the statistical indicators of R<sup>2</sup>, RMSE and GMER is more accurate compared with the Mohr-Coulomb (MC) model. The results of the numerical model were calibrated at the end of construction for Kabudval Dam and showed that the maximum increase in pore water pressure, stress, settlement and horizontal displacement occurs in the central part and its value in the axis and middle part of the dam is more than its sides. The middle part and close to the dam axis have similar changes with the filling process of the dam body, while with moving away from the dam axis due to the transfer of stresses to the sides, they have less impact from the dam filling process. In addition, in the central part, the effects of filter and drainage are low. Accurate prediction of pore water pressure, settlement, soil stress and pore water pressure coefficient (R<sub>u</sub>) in the body of earth dams during construction is one of the necessary measures in the management of earth dam stability. Because the behavior of the earth dams is nonlinear, it is necessary to use finite element methods and suitable soil behavior models. In the present study, which is a case study, a three-dimensional numerical simulation was performed using the Plaxis software for the Kabudval Dam located in Golestan province, Iran. The values obtained from the numerical simulation were compared with the corresponding measured values using the dam instruments. Calibration was carried out using the back analysis method (BAM) and some dam geotechnical parameters were corrected based on BAM. The results showed that the hardening soil (HS) model with the statistical indicators of R<sup>2</sup>, RMSE and GMER is more accurate compared with the Mohr-Coulomb (MC) model. The results of the numerical model were calibrated at the end of construction for Kabudval Dam and showed that the maximum increase in pore water pressure, stress, settlement and horizontal displacement occurs in the central part and its value in the axis and middle part of the dam is more than its sides. The middle part and close to the dam axis have similar changes with the filling process of the dam body, while with moving away from the dam axis due to the transfer of stresses to the sides, they have less impact from the dam filling process. In addition, in the central part, the effects of filter and drainage are low. Kabudval Dam Plaxis finite element method back analysis Hardening soil model https://ceej.aut.ac.ir/article_4049_89a4779d3836ea432f7ea074e522a17e.pdf
Amirkabir University of Technology Amirkabir Journal of Civil Engineering 2588-297X 53 9 2021 11 22 Analysis of Regression-Based Models for Prediction of Depth Temperature of Asphalt Layers – A Review Analysis of Regression-Based Models for Prediction of Depth Temperature of Asphalt Layers – A Review 3985 4006 4080 10.22060/ceej.2020.18131.6793 FA Mohammad Sedighian-Fard Department of Civil Engineering, Urmia University, Urmia, Iran 0000-0003-2668-0123 Nader Solatifar Department of Civil Engineering, Urmia University, Urmia, Iran 0000-0002-3487-8503 Journal Article 2020 03 30 Due to the viscoelastic behavior of asphalt mixtures, the depth temperature of asphalt layers is very important in the structural evaluation of flexible pavements. Depth temperature could be measured directly in the field or maybe predicted using prediction models. This paper presents a comprehensive analysis of different twelve regression-based models for the prediction of depth temperature of asphalt layers. With reference to the literature, required input parameters, sensitivity analysis, evaluation of prediction performance, as well as a comparison of the goodness of these models were discussed. Furthermore, calibrated models for different local conditions were presented. This is due to the fact that the original models were usually developed in specific geographical regions and climatic conditions. Results show that the regression-based models have a good performance and high accuracy in predicting the depth temperature of asphalt layers. Among the investigated models, according to the variety of data (or parameters) used in the model development, performance, considering the effect of various parameters, the BELLS model was introduced as one of the best regression-based models for the prediction of depth temperature of asphalt layers. The model developed by Solatifar et al. as a new version of the BELLS model showed very good accuracy for newly constructed pavements. In addition, with applying some modifications, it could be possible to use these models in different pavements and local conditions. Due to the viscoelastic behavior of asphalt mixtures, the depth temperature of asphalt layers is very important in the structural evaluation of flexible pavements. Depth temperature could be measured directly in the field or maybe predicted using prediction models. This paper presents a comprehensive analysis of different twelve regression-based models for the prediction of depth temperature of asphalt layers. With reference to the literature, required input parameters, sensitivity analysis, evaluation of prediction performance, as well as a comparison of the goodness of these models were discussed. Furthermore, calibrated models for different local conditions were presented. This is due to the fact that the original models were usually developed in specific geographical regions and climatic conditions. Results show that the regression-based models have a good performance and high accuracy in predicting the depth temperature of asphalt layers. Among the investigated models, according to the variety of data (or parameters) used in the model development, performance, considering the effect of various parameters, the BELLS model was introduced as one of the best regression-based models for the prediction of depth temperature of asphalt layers. The model developed by Solatifar et al. as a new version of the BELLS model showed very good accuracy for newly constructed pavements. In addition, with applying some modifications, it could be possible to use these models in different pavements and local conditions. Asphalt Pavement Depth Temperature of Asphalt Layers Temperature Predictive Models Regression-Based Model BELLS Model https://ceej.aut.ac.ir/article_4080_3b9be7e15b46c42911f39a4a9e861022.pdf
Amirkabir University of Technology Amirkabir Journal of Civil Engineering 2588-297X 53 9 2021 11 22 Evaluating the influence of temperature and fiber type on the mechanical properties of self-compacting lightweight concrete Evaluating the influence of temperature and fiber type on the mechanical properties of self-compacting lightweight concrete 4007 4028 4038 10.22060/ceej.2020.18185.6794 FA Moosa Mazloom Sajjad Lotfi Ahangar Kolaee M.Sc., Civil Engineering Department, Shahid Rajaee Teacher Training University, Tehran, Iran Journal Article 2020 03 30 The advantages of self-compacting lightweight concrete have led to its increasing use in the construction industry. The use of different fibers in this type of concrete causes problems such as reduced flowability and sensitivity to temperature, which challenges the type and method of using fibers. In the present study, the effects of glass and basalt fibers (GF and BF) and temperature on the properties of self-compacting lightweight concrete (SCLC) have been investigated. For this aim, the fresh and hardened properties of 12 SCLC mixes have been investigated that contained monotype and hybrid fibers. The self-compacting properties of SCLC were assessed using slump flow, T500, V-funnel, and J-ring. After 28 days of curing, the compressive, splitting tensile and flexural strengths tests were performed to characterize the mechanical properties of SCLC at room temperature of 20 °C and high temperatures of 100 and 300 °C. The test results of fresh concrete showed that all the mixes could be defined as SCLC with good flowability, viscosity, and passing ability. Hardened test results indicated that the addition of the fibers reduced the compressive strength and increased the tensile strength, flexural strength, and fracture energy. Moreover, compared to monotype fibers, the hybrid ones effectively enhanced the mechanical behaviors of SCLC. The advantages of self-compacting lightweight concrete have led to its increasing use in the construction industry. The use of different fibers in this type of concrete causes problems such as reduced flowability and sensitivity to temperature, which challenges the type and method of using fibers. In the present study, the effects of glass and basalt fibers (GF and BF) and temperature on the properties of self-compacting lightweight concrete (SCLC) have been investigated. For this aim, the fresh and hardened properties of 12 SCLC mixes have been investigated that contained monotype and hybrid fibers. The self-compacting properties of SCLC were assessed using slump flow, T500, V-funnel, and J-ring. After 28 days of curing, the compressive, splitting tensile and flexural strengths tests were performed to characterize the mechanical properties of SCLC at room temperature of 20 °C and high temperatures of 100 and 300 °C. The test results of fresh concrete showed that all the mixes could be defined as SCLC with good flowability, viscosity, and passing ability. Hardened test results indicated that the addition of the fibers reduced the compressive strength and increased the tensile strength, flexural strength, and fracture energy. Moreover, compared to monotype fibers, the hybrid ones effectively enhanced the mechanical behaviors of SCLC. self-compacting lightweight concrete Fiber-reinforced concrete glass fiber Basalt fiber high temperature https://ceej.aut.ac.ir/article_4038_56577889b3c1cd083b6d7b32d32f99d5.pdf
Amirkabir University of Technology Amirkabir Journal of Civil Engineering 2588-297X 53 9 2021 11 22 Evaluation of Compressive Bearing Capacity of Long Offshore Steel Piles Driven in the Persian Gulf Evaluation of Compressive Bearing Capacity of Long Offshore Steel Piles Driven in the Persian Gulf 4029 4060 3995 10.22060/ceej.2020.18158.6795 FA AmirHossein Shamshirgaran Faculty of Civil, Water and Environmental Engineering, Shahid Beheshti University (SBU), Tehran, Iran Babak Ebrahimian Faculty of Civil, Water and Environmental Engineering, Shahid Beheshti University (SBU), Tehran, Iran Journal Article 2020 03 31 <span style="letter-spacing: .05pt;">Long-driven steel piles are widely used in the foundation of fixed offshore oil and gas extraction platforms due to the existence of physical limitations, heavy loads and weak shallow seabed soil layers. There are different methods to determine the pile bearing capacity, including static analysis, using the results of in-situ tests, as well as static and dynamic pile loading tests. In recent years, the in-situ cone penetration test has considerably been developed in the design of offshore piles owing to its high accuracy, continuous recoding across the depth, and similarity to pile. Additionally, the application of in-situ tests for pile design is of great interest due to difficulties in obtaining undisturbed soil samples at sea. The dynamic pile load test is also considered as an alternative and economical way to the static pile load test, particularly in offshore environments. In this paper, for the first time, a comprehensive data bank, including soil engineering parameters derived from laboratory and in-situ tests as well as field measurements obtained from dynamic pile tests in short, medium, and long-term conditions, is developed for the Persian Gulf - South Pars field. Afterward, fourteen methods, including four offshore static analysis methods and ten direct methods based on cone penetration test results, are selected and applied to estimate the axial compressive bearing capacity of steel pipe piles driven in the studied area. The results obtained from different methods are compared with the results of dynamic pile tests at three mentioned times and evaluated using the statistical criteria. According to the findings of the conducted statistical analyses, the lowest precision and prediction quality are provided in the four static analysis methods compared to the CPT-based methods for the developed data bank. The values of pile total ultimate bearing capacity obtained from the static analysis methods are on average 70%, 63%, and 35% higher than the corresponding values measured by the dynamic pile tests in short, medium, and long-term conditions, respectively.</span> <span style="letter-spacing: .05pt;">Long-driven steel piles are widely used in the foundation of fixed offshore oil and gas extraction platforms due to the existence of physical limitations, heavy loads and weak shallow seabed soil layers. There are different methods to determine the pile bearing capacity, including static analysis, using the results of in-situ tests, as well as static and dynamic pile loading tests. In recent years, the in-situ cone penetration test has considerably been developed in the design of offshore piles owing to its high accuracy, continuous recoding across the depth, and similarity to pile. Additionally, the application of in-situ tests for pile design is of great interest due to difficulties in obtaining undisturbed soil samples at sea. The dynamic pile load test is also considered as an alternative and economical way to the static pile load test, particularly in offshore environments. In this paper, for the first time, a comprehensive data bank, including soil engineering parameters derived from laboratory and in-situ tests as well as field measurements obtained from dynamic pile tests in short, medium, and long-term conditions, is developed for the Persian Gulf - South Pars field. Afterward, fourteen methods, including four offshore static analysis methods and ten direct methods based on cone penetration test results, are selected and applied to estimate the axial compressive bearing capacity of steel pipe piles driven in the studied area. The results obtained from different methods are compared with the results of dynamic pile tests at three mentioned times and evaluated using the statistical criteria. According to the findings of the conducted statistical analyses, the lowest precision and prediction quality are provided in the four static analysis methods compared to the CPT-based methods for the developed data bank. The values of pile total ultimate bearing capacity obtained from the static analysis methods are on average 70%, 63%, and 35% higher than the corresponding values measured by the dynamic pile tests in short, medium, and long-term conditions, respectively.</span> Offshore pile axial compressive bearing capacity cone penetration test (CPT) dynamic pile test Persian Gulf https://ceej.aut.ac.ir/article_3995_d464b5ac99e74462f321c06ccacc4bff.pdf
Amirkabir University of Technology Amirkabir Journal of Civil Engineering 2588-297X 53 9 2021 11 22 Formulating a new efficient simple element for statics, buckling and free vibration analysis of Timoshenko’s beam Formulating a new efficient simple element for statics, buckling and free vibration analysis of Timoshenko’s beam 4061 4080 3943 10.22060/ceej.2020.18186.6796 FA Majid Yaghoobi Department of civil engineering, Faculty of engineering, University of Torbat Heydarieh, Torbat Heydarieh, Iran. Mohsen Sedaghatjo Civil Engineering Department, Engineering Faculty, University of Torbat Heydarieh, Torbat Heydarieh, Iran. Reyhaneh Alizadeh Civil Engineering Department, Engineering Faculty, University of Torbat Heydarieh, Torbat Heydarieh, Iran. Mohammad Karkon Civil Engineering Department, Larestan Branch Islamic Azad University, Larestan, Iran. Journal Article 2020 03 31 <span style="letter-spacing: .05pt;">The beams are really useful for a large number of engineering structures. In this article, a simple, robust beam element will be formulated. Other researchers utilized several theories such as Euler-Bernoulli, Timoshenko and higher-order shear for analyzing the beams. The proposed formulation will be written based on satisfying the equilibrium equation. Using the equilibrium equation reduces the number of unknowns in addition to improving the efficiency of the new element. The suggested element has only two nods and two degrees of freedom per node. The third and second-order polynomials will be used for vertical displacement and rotation fields, respectively. After calculating the matrix of shape functions, the governing equations of statics, free vibration and buckling analysis can be written. Finally, using the suggested element, static analysis, free vibration and buckling were performed on several problems. To prove the efficiency of the new element, a large number of benchmark tests will be utilized. These numerical tests have various support conditions and different aspect ratios. With the help of these tests, rapid convergence and high accuracy of the proposed element will be shown. The new element has high efficiency in all of the static, free vibration and buckling analysis for both thin and thick beams besides its simplicity. Good element answers of other researchers will be available to have a better comparison. </span> <span style="letter-spacing: .05pt;">The beams are really useful for a large number of engineering structures. In this article, a simple, robust beam element will be formulated. Other researchers utilized several theories such as Euler-Bernoulli, Timoshenko and higher-order shear for analyzing the beams. The proposed formulation will be written based on satisfying the equilibrium equation. Using the equilibrium equation reduces the number of unknowns in addition to improving the efficiency of the new element. The suggested element has only two nods and two degrees of freedom per node. The third and second-order polynomials will be used for vertical displacement and rotation fields, respectively. After calculating the matrix of shape functions, the governing equations of statics, free vibration and buckling analysis can be written. Finally, using the suggested element, static analysis, free vibration and buckling were performed on several problems. To prove the efficiency of the new element, a large number of benchmark tests will be utilized. These numerical tests have various support conditions and different aspect ratios. With the help of these tests, rapid convergence and high accuracy of the proposed element will be shown. The new element has high efficiency in all of the static, free vibration and buckling analysis for both thin and thick beams besides its simplicity. Good element answers of other researchers will be available to have a better comparison. </span> Beam element Equilibrium equation Static analysis free vibration Buckling https://ceej.aut.ac.ir/article_3943_da21bae82c02d1e2b8168d57cd3fbab7.pdf
Amirkabir University of Technology Amirkabir Journal of Civil Engineering 2588-297X 53 9 2021 11 22 Influence of ambient flow on the behavior of dense effluent discharged into the water environment Influence of ambient flow on the behavior of dense effluent discharged into the water environment 4081 4102 4224 10.22060/ceej.2020.18190.6798 FA Vahid Babaiynejad Faculty of Civil and Environmental Engineering, Amir Kabir University of Technology, Tehran, Iran. Babak Khorsandi Faculty of Civil and Environmental Engineering, Amir Kabir University of Technology, Tehran, Iran. Journal Article 2020 03 31 Due to the limitation of natural freshwater resources and population growth in recent decades, human has turned to the development of water desalination plants to fill the gap between supply and demand. The most important environmental problem of desalination plants is the production of brine (containing a high concentration of salt) that is discharged directly into the sea. Various factors affect the dilution rate of discharged effluent, one of the most important of which is the ambient flow. In this study, using CorJet integral model, the effect of ambient flow velocity on the characteristics of jets and plumes and their dilution rates are investigated. The direction and magnitude of the ambient flow affect the mixing of the discharged effluent. This effect is the greatest when the ambient flow velocity is higher than the discharged effluent velocity. In this case, the effluent is completely diverted from its original path and advected in the direction of the ambient flow. In the presence of ambient flow, the greater the discharge angle relative to the horizon, the greater the effluent trajectory length and dilution rate. Furthermore, the discharge angle of 90° results in the highest dilution rate of effluents when the ambient flow is present. When the angle between the effluent discharge and the ambient flow (0 <ϕ <180) increases, the jet trajectory length, the horizontal distance from the discharge point to where the effluent impacts the ground, and the effluent dilution rate decrease. Due to the limitation of natural freshwater resources and population growth in recent decades, human has turned to the development of water desalination plants to fill the gap between supply and demand. The most important environmental problem of desalination plants is the production of brine (containing a high concentration of salt) that is discharged directly into the sea. Various factors affect the dilution rate of discharged effluent, one of the most important of which is the ambient flow. In this study, using CorJet integral model, the effect of ambient flow velocity on the characteristics of jets and plumes and their dilution rates are investigated. The direction and magnitude of the ambient flow affect the mixing of the discharged effluent. This effect is the greatest when the ambient flow velocity is higher than the discharged effluent velocity. In this case, the effluent is completely diverted from its original path and advected in the direction of the ambient flow. In the presence of ambient flow, the greater the discharge angle relative to the horizon, the greater the effluent trajectory length and dilution rate. Furthermore, the discharge angle of 90° results in the highest dilution rate of effluents when the ambient flow is present. When the angle between the effluent discharge and the ambient flow (0 <ϕ <180) increases, the jet trajectory length, the horizontal distance from the discharge point to where the effluent impacts the ground, and the effluent dilution rate decrease. CorJet Dilution Jet plume Brine discharge https://ceej.aut.ac.ir/article_4224_690d83983a63aa1818423fd6edd3bfdb.pdf