Amirkabir University of TechnologyAmirkabir Journal of Civil Engineering2588-297X52420200621Investigating Discharge Variation in Various Emitters Due to the Effect of Refined WastewaterInvestigating Discharge Variation in Various Emitters Due to the Effect of Refined Wastewater783796310110.22060/ceej.2018.14863.5764FAYahyaChoopanWater Engineering Department of Gorgan university0000-0001-6275-6717SomayehEmamiWater Engineering Department of TabrizJournal Article20180819Research indicates that the use of Emitters in more suitable for use with wastewater than other irrigation methods. In order to study the Emitter’s discharge variation by using refined wastewater in drip irrigation systems, two drip irrigation systems (a water well system as control treatment and the other with a Miandoab refinery refined wastewater as main treatment) was installed and implemented. Due to the difference and sensitivity of various emitters against physical clogs affected by water-soluble, four emitters consists of 4-liter Euro-droplet emitter with 1-meter outlet distances, two 4-liter Iran drip emitter with 1-meter outlet distances and the 16mm type tube was used at 20 to 30 cm output distances. The systems were tested in a 4-meter pressure mode and it was determined that the Euro-drip emitter has the best performance and with technical and appropriate management, the system has the ability to run with the refined wastewater. The results showed that the Euro-drip emitter indicates the lowest percentage of discharge decreases. The highest emitter absolute dispersion uniformity percentage during operation with a 4-meter pressure is related to the Euro-drip with 95.6% and the lowest value for the Iran-drip with 88.15%. Also, Iran-drip emitter the most discharge decrease by 29.4%.Research indicates that the use of Emitters in more suitable for use with wastewater than other irrigation methods. In order to study the Emitter’s discharge variation by using refined wastewater in drip irrigation systems, two drip irrigation systems (a water well system as control treatment and the other with a Miandoab refinery refined wastewater as main treatment) was installed and implemented. Due to the difference and sensitivity of various emitters against physical clogs affected by water-soluble, four emitters consists of 4-liter Euro-droplet emitter with 1-meter outlet distances, two 4-liter Iran drip emitter with 1-meter outlet distances and the 16mm type tube was used at 20 to 30 cm output distances. The systems were tested in a 4-meter pressure mode and it was determined that the Euro-drip emitter has the best performance and with technical and appropriate management, the system has the ability to run with the refined wastewater. The results showed that the Euro-drip emitter indicates the lowest percentage of discharge decreases. The highest emitter absolute dispersion uniformity percentage during operation with a 4-meter pressure is related to the Euro-drip with 95.6% and the lowest value for the Iran-drip with 88.15%. Also, Iran-drip emitter the most discharge decrease by 29.4%.Amirkabir University of TechnologyAmirkabir Journal of Civil Engineering2588-297X52420200621Comparison of the effects of micro and macro polymer fiber on the mechanical and
durability of roller-compacted concrete pavementsComparison of the effects of micro and macro polymer fiber on the mechanical and
durability of roller-compacted concrete pavements797808328010.22060/ceej.2019.14895.5774FAAliakbarRamezanianporدانشکده عمران و محیط زیست، دانشگاه صنعتی امیرکبیر، تهران، ایرانJafarSobhaniعضو هیات علمیAlirezaPourkhorshidiبخش فناوری بتن، مرکز تحقیقات راه، مسکن و شهرسازی، تهران،Mohamad MehdiLotfiAUTJournal Article20180828A laboratory study was performed to determine the benefits of micro and macro fibers in roller-compacted concrete (RCC) for pavements by measuring the RCCs mechanical and durability properties. To this aim, three RCC mixtures with use of micro and macro polyolefin-based fibers in two volumetric content (1 and 2 kg/m3) were prepared and the mechanical properties (compressive strength and flexures strengths (modulus of rupture and toughness)) and durability properties (salt scaling under freeze-thaw and water permeability) were evaluated. The results emphasized that the macro fibers could be efficiently enhanced the toughness in comparison with the microfibers. Moreover, the water permeability of fiber-concrete decreased up to 20% in comparison with the reference concrete. Furthermore, it was found that the application of microfibers in comparison with macro fibers significantly improved the salt-scaling resistance of concrete.A laboratory study was performed to determine the benefits of micro and macro fibers in roller-compacted concrete (RCC) for pavements by measuring the RCCs mechanical and durability properties. To this aim, three RCC mixtures with use of micro and macro polyolefin-based fibers in two volumetric content (1 and 2 kg/m3) were prepared and the mechanical properties (compressive strength and flexures strengths (modulus of rupture and toughness)) and durability properties (salt scaling under freeze-thaw and water permeability) were evaluated. The results emphasized that the macro fibers could be efficiently enhanced the toughness in comparison with the microfibers. Moreover, the water permeability of fiber-concrete decreased up to 20% in comparison with the reference concrete. Furthermore, it was found that the application of microfibers in comparison with macro fibers significantly improved the salt-scaling resistance of concrete.Amirkabir University of TechnologyAmirkabir Journal of Civil Engineering2588-297X52420200621Evaluation and comparison of seismic behavior of composite and steel shear-walls in
construction frames with semi-enclosed composite columnsEvaluation and comparison of seismic behavior of composite and steel shear-walls in
construction frames with semi-enclosed composite columns809826317510.22060/ceej.2018.14906.5776FASeyed FathollahSajediAssociate Professor, Department of Civil Engineering,Faculty of Engineering, Islamic Azad University of Ahvaz0000-0003-3933-2793MehdiHarizaviIAU of AbadanJournal Article20180829The research purpose is to evaluate and compare the seismic behavior of composite and steel shear-walls in construction frames with semi-enclosed composite columns. The numerical behavior of composite and steel shear-walls with semi-enclosed columns was investigated and then the parameters affecting the seismic behavior of the composite shear-walls under cyclic loading were analyzed with the Abaqus software. Software validation was performed with two laboratory samples. The results showed that the use of Semi-enclosed columns increased by 48% and 56% in the ultimate strength of the composite shear-walls with unilateral and bilateral concrete. These columns improved ductility and energy depletion. The semi-enclosed columns caused a 15% increase in the ultimate strength of the steel shear-walls and had a limited impact on energy absorption. The increase in steel plate thickness of the composite shear-walls from 2 to 4 and 4 to 6 mm, resulted in 16% and 14% improvement in the ultimate strength and energy depletion, respectively. The gap of 11.3 mm between the steel frame and the concrete wall was optimum. By reducing the diameter of the gap to 6.5, the strength decreased by 1.5% and with increasing the diameter of the gap to 9.16 mm, strength dropped by 7%. By increasing the thickness of the cross-section of the composite columns from 2 to 5 and from 5 to 8 mm, the strength increased 25.3% and 12.1%, respectively. With an increase in strength of concrete from 30 to 72.5 MPa (142% increase), the structural strength increased by only 15%.The research purpose is to evaluate and compare the seismic behavior of composite and steel shear-walls in construction frames with semi-enclosed composite columns. The numerical behavior of composite and steel shear-walls with semi-enclosed columns was investigated and then the parameters affecting the seismic behavior of the composite shear-walls under cyclic loading were analyzed with the Abaqus software. Software validation was performed with two laboratory samples. The results showed that the use of Semi-enclosed columns increased by 48% and 56% in the ultimate strength of the composite shear-walls with unilateral and bilateral concrete. These columns improved ductility and energy depletion. The semi-enclosed columns caused a 15% increase in the ultimate strength of the steel shear-walls and had a limited impact on energy absorption. The increase in steel plate thickness of the composite shear-walls from 2 to 4 and 4 to 6 mm, resulted in 16% and 14% improvement in the ultimate strength and energy depletion, respectively. The gap of 11.3 mm between the steel frame and the concrete wall was optimum. By reducing the diameter of the gap to 6.5, the strength decreased by 1.5% and with increasing the diameter of the gap to 9.16 mm, strength dropped by 7%. By increasing the thickness of the cross-section of the composite columns from 2 to 5 and from 5 to 8 mm, the strength increased 25.3% and 12.1%, respectively. With an increase in strength of concrete from 30 to 72.5 MPa (142% increase), the structural strength increased by only 15%.Amirkabir University of TechnologyAmirkabir Journal of Civil Engineering2588-297X52420200621Experimental Investigation of Downstream Erosion Control of Stepped Spillways
using Microsilica - Structured and Nano MaterialsExperimental Investigation of Downstream Erosion Control of Stepped Spillways
using Microsilica - Structured and Nano Materials827840317010.22060/ceej.2018.14919.5781FAAmirGhaderiDepartment of Civil Engneering, Faculty of Engneering, University of Zanjan, Iran0000-0002-8661-6302RasoulDaneshfarazDept. of Civil Engineering, University of Maragheh, Iran0000-0003-1012-8342RezaZaerkabehcDepartment of Civil Engneering, Faculty of Engneering, Sahand University Of Technology, IranForoughAshkanA Faculty Member, Maragheh University, Maragheh, IranJournal Article20180901Nano-structured materials are waterproof, and they can be used for the reduction of scouring in alluvial beds. In this research, the impact of clay additive and Nanomaterials and Silicafume to sedimentary bed materials of stepped spillway on controlling erosion and scouring are investigated as a Nonstructural solution. Firstly, the effect of the number of steps and flow regime on downstream scouring were studied. The results show that by increasing the number of steps on the same slop of chute and in a skimming flow regime on the steps, the depth and length of the scouring on the downstream of the stepped spillway increases. Then the impact of some injected additives to the sedimentary bed with the same number of steps and skimming flow regime was investigated. The results prove the positive effect of clay and its mixture with Nano-clay and Silicafume on the reduction of scouring length and depth reduction on the weir downstream. The best performance between three different compositions is related to the mixture of clay with Nano-clay and Silicafume in which they contributed in reduction profile of scoring by 48.74% and 46.38% respectively compared with the reference model. At the same time injection of clay to the sedimentary bed reduced the depth and length of scouring by 35.63% and 20.88% and injection of clay with Nanoclay reduced the depth and length of scouring by 41.41% and 37.75% respectively. These results can state the success of clay, Nano-clay, and Silicafume on the scouring control mechanism at downstream of hydraulic structures, especially in flood discharges.Nano-structured materials are waterproof, and they can be used for the reduction of scouring in alluvial beds. In this research, the impact of clay additive and Nanomaterials and Silicafume to sedimentary bed materials of stepped spillway on controlling erosion and scouring are investigated as a Nonstructural solution. Firstly, the effect of the number of steps and flow regime on downstream scouring were studied. The results show that by increasing the number of steps on the same slop of chute and in a skimming flow regime on the steps, the depth and length of the scouring on the downstream of the stepped spillway increases. Then the impact of some injected additives to the sedimentary bed with the same number of steps and skimming flow regime was investigated. The results prove the positive effect of clay and its mixture with Nano-clay and Silicafume on the reduction of scouring length and depth reduction on the weir downstream. The best performance between three different compositions is related to the mixture of clay with Nano-clay and Silicafume in which they contributed in reduction profile of scoring by 48.74% and 46.38% respectively compared with the reference model. At the same time injection of clay to the sedimentary bed reduced the depth and length of scouring by 35.63% and 20.88% and injection of clay with Nanoclay reduced the depth and length of scouring by 41.41% and 37.75% respectively. These results can state the success of clay, Nano-clay, and Silicafume on the scouring control mechanism at downstream of hydraulic structures, especially in flood discharges.Amirkabir University of TechnologyAmirkabir Journal of Civil Engineering2588-297X52420200621The conjunction of the feature extraction method with AI-based ensemble statistical
downscaling modelsThe conjunction of the feature extraction method with AI-based ensemble statistical
downscaling models841858317310.22060/ceej.2018.14986.5806FAZahraRazzaghzadehcivil engineer, faculty of civil engineering, Tabriz university, Tabriz, IranVahidNouraniwater resource management, factuly of civil engineering, university of Tabriz, Tabriz,IranNazaninBehfarwater resource management, faculty of civil engineering, university of Tabriz, Tabriz, Iran0000-0002-8211-4006Journal Article20180915In this study, two general circulation models (GCMs) (Can-ESM2, BNU-ESM) were used to simulate the future precipitation of Tabriz city. The weakness of GCMs is the coarse resolution of climate variables in which the different methods of downscaling is about to solve this deficiency. In this study, the Artificial Intelligence (AI) models, i.e., Artificial Neural Network (ANN) and Adaptive neuro-fuzzy inference system (ANFIS), were used to statistically downscale the climate variables of GCMs. Without any doubt, the most important step during the use of these models is selecting the dominant inputs among huge large-scale GCM data. So in this study for the selection of dominant inputs, decision tree, and mutual information (MI) feature extraction methods were used. Also, the ensemble techniques were used to evaluate the efficiency of downscaling models and to decrease the uncertainties. A comparison of the result of downscaling models indicated that the ensemble technique (i.e., hybrid of ANN and ANFIS) with dominant inputs based on decision tree feature extraction methods presents better performance. In both GCMs, the application of the downscaling ensemble couple with dominant predictors based on a decision tree model in precipitation downscaling showed 10%-38% increase in DC in versus the individual ANN and ANFIS downscaling models. The projection precipitation of Tabriz synoptic station for future (2020-2060) by proposed ensemble AI-based model indicated 30%-40% precipitation decreases under RCP4.5 and RCP8.5 scenarios.In this study, two general circulation models (GCMs) (Can-ESM2, BNU-ESM) were used to simulate the future precipitation of Tabriz city. The weakness of GCMs is the coarse resolution of climate variables in which the different methods of downscaling is about to solve this deficiency. In this study, the Artificial Intelligence (AI) models, i.e., Artificial Neural Network (ANN) and Adaptive neuro-fuzzy inference system (ANFIS), were used to statistically downscale the climate variables of GCMs. Without any doubt, the most important step during the use of these models is selecting the dominant inputs among huge large-scale GCM data. So in this study for the selection of dominant inputs, decision tree, and mutual information (MI) feature extraction methods were used. Also, the ensemble techniques were used to evaluate the efficiency of downscaling models and to decrease the uncertainties. A comparison of the result of downscaling models indicated that the ensemble technique (i.e., hybrid of ANN and ANFIS) with dominant inputs based on decision tree feature extraction methods presents better performance. In both GCMs, the application of the downscaling ensemble couple with dominant predictors based on a decision tree model in precipitation downscaling showed 10%-38% increase in DC in versus the individual ANN and ANFIS downscaling models. The projection precipitation of Tabriz synoptic station for future (2020-2060) by proposed ensemble AI-based model indicated 30%-40% precipitation decreases under RCP4.5 and RCP8.5 scenarios.Amirkabir University of TechnologyAmirkabir Journal of Civil Engineering2588-297X52420200621An Investigation into the Impact of Fire on Lateral Stability and Strength of Thin Steel
Plate Shear WallsAn Investigation into the Impact of Fire on Lateral Stability and Strength of Thin Steel
Plate Shear Walls859872317110.22060/ceej.2018.15003.5809FAGhasemPachidehPhd Candidate, civil faculty, semnan universityMajidGholhaki0000-0002-9904-8623YoonesNooriferdowsi universityJournal Article20180919The SPSWs has been enthusiastically applied in some of the tall buildings across the world as a novel lateral load-bearing system and due to their proper stiffness, strength, ductility, and energy absorption, as well as remarkable reduction in buildings’, weigh compared to the concrete cases, they are deemed as an efficient alternative for the traditional load-resisting systems. Fire-related hazards and their impacts on the structural systems have been of major concern for practitioners, which is of utmost significance for special structures and tall buildings. Accordingly, in the case of thin steel plate shear walls, fire is most likely to leave detrimental effects on the lateral stability and strength of them due to their small values of thickness. To better understand the behavior of such systems in the event of a fire, this paper aims to investigate the impact of heat caused by a fire on the stability, elastic stiffness and yield strength of a 3-storey frame equipped with SPSW system. Based on the results derived by connected stress-heat analyses, thickening the wall results in a substantial reduction in the column’s deformations. Moreover, an increase in thickness and yield strength of the steel plate plays an effective role in less reduction in yield strength and elastic stiffness of the system after fire events although, while the plate thickness is kept constant, the system’s elastic stiffness does not vary as the yield strength raises. In addition, simple relations were achieved to estimate the post-fire elastic stiffness and yield strength of the SPSW system.The SPSWs has been enthusiastically applied in some of the tall buildings across the world as a novel lateral load-bearing system and due to their proper stiffness, strength, ductility, and energy absorption, as well as remarkable reduction in buildings’, weigh compared to the concrete cases, they are deemed as an efficient alternative for the traditional load-resisting systems. Fire-related hazards and their impacts on the structural systems have been of major concern for practitioners, which is of utmost significance for special structures and tall buildings. Accordingly, in the case of thin steel plate shear walls, fire is most likely to leave detrimental effects on the lateral stability and strength of them due to their small values of thickness. To better understand the behavior of such systems in the event of a fire, this paper aims to investigate the impact of heat caused by a fire on the stability, elastic stiffness and yield strength of a 3-storey frame equipped with SPSW system. Based on the results derived by connected stress-heat analyses, thickening the wall results in a substantial reduction in the column’s deformations. Moreover, an increase in thickness and yield strength of the steel plate plays an effective role in less reduction in yield strength and elastic stiffness of the system after fire events although, while the plate thickness is kept constant, the system’s elastic stiffness does not vary as the yield strength raises. In addition, simple relations were achieved to estimate the post-fire elastic stiffness and yield strength of the SPSW system.Amirkabir University of TechnologyAmirkabir Journal of Civil Engineering2588-297X52420200621Effect of Vertical Component of Earthquake on Concrete Storage Tanks with Flexible
Walls Using Coupled Finite Element and Smoothed Particle Hydrodynamics MethodEffect of Vertical Component of Earthquake on Concrete Storage Tanks with Flexible
Walls Using Coupled Finite Element and Smoothed Particle Hydrodynamics Method873888322610.22060/ceej.2019.15153.5841FASepehrRassoulpourPhD student in Earthquake Engineering, Dept.of Civil, Water and Environmental engineering, Shahid Beheshti University, Tehran, IranMohammadSafiAssistant Professor, Dept.of civil, Water and Environmental Engineering, Shahid Beheshti University, Tehran, IranJournal Article20181021In this research, the Seismic behavior of concrete rectangular fluid tanks has been studied and the importance of the effect of the earthquake’s vertical component investigated. The structure of tank and medium of the water has been modeled using finite element and smoothed particle hydrodynamics methods respectively. The smooth particle hydrodynamics which is a meshfree method, has many advantages over other traditional grid-based methods. For verification purposes, the modeling accuracy compared with the available experimental and numerical results. The analysis ran under horizontal records with predominant periods in different ranges, once considering vertical component and another time without it. Afterward, the parameters of sloshing height base shear, force in unit width and displacement of the wall have been obtained for comparison. The results show that consideration of vertical component in analysis has a negligible effect on sloshing response but it is significant on structure’s response. Meanwhile, the maximum sloshing occurs in analysis under horizontal record with high predominant period. Tanks with different thicknesses or in other words, different flexibilities of walls, show completely different sloshing and structure response. Also considering walls that are parallel to direction of earthquake as flexible, has significant effect on response of the structure. As a result, the effect of vertical component and flexibility of walls must be considered in seismic analysis of tanks.In this research, the Seismic behavior of concrete rectangular fluid tanks has been studied and the importance of the effect of the earthquake’s vertical component investigated. The structure of tank and medium of the water has been modeled using finite element and smoothed particle hydrodynamics methods respectively. The smooth particle hydrodynamics which is a meshfree method, has many advantages over other traditional grid-based methods. For verification purposes, the modeling accuracy compared with the available experimental and numerical results. The analysis ran under horizontal records with predominant periods in different ranges, once considering vertical component and another time without it. Afterward, the parameters of sloshing height base shear, force in unit width and displacement of the wall have been obtained for comparison. The results show that consideration of vertical component in analysis has a negligible effect on sloshing response but it is significant on structure’s response. Meanwhile, the maximum sloshing occurs in analysis under horizontal record with high predominant period. Tanks with different thicknesses or in other words, different flexibilities of walls, show completely different sloshing and structure response. Also considering walls that are parallel to direction of earthquake as flexible, has significant effect on response of the structure. As a result, the effect of vertical component and flexibility of walls must be considered in seismic analysis of tanks.Amirkabir University of TechnologyAmirkabir Journal of Civil Engineering2588-297X52420200621Optimizing the Weight of 3D Steel structures by spectrum dynamic analysis and soft
computing algorithmOptimizing the Weight of 3D Steel structures by spectrum dynamic analysis and soft
computing algorithm889918327910.22060/ceej.2019.15072.5823FAHamidrezaAbbasianjahromiAssistant Prof, dept. Civil Engineering, K. N. Toosi University of Technology, Tehran, Iran0000-0003-3249-2882SaeedAsil GharebaghiAssistant Prof, dept. Civil Engineering, K. N. Toosi University of Technology, Tehran, Iran0000-0001-8966-5276Mohammad SadeghEshaghi KhanghahK. N. Toosi University of TechnologyJournal Article20181002Regarding the importance of the optimized and economical design of structures, reducing the total weight of structures has been considered. This approach leads to a decrease in the cost of building projects. In another point of view, reducing the weight of structures will be associated with decreasing the dimension of different elements so it can increase the likelihood of strength failure in the structures. This paper intends to apply the soft computing technique, firstly, to bring a new algorithm for minimizing the weight of structures with respect to satisfying different technical constraints and secondly, to improve the speed of answer. To achieve the second goal, various methods including the modified genetic algorithm, the modified ant colony, and artificial neural network, were applied and tested. Some performance indicators such as speed of answer, accuracy, etc. were selected to compare the output of those mentioned approaches with traditional calculations. The obtained results showed that the modified ant colony algorithm has better performance in terms of speed of answer and accuracy. While several previous investigations have been looked at the problem of structure weight optimization from a two-dimensional perspective, this paper developed three-dimensional modeling by applying the spectrum dynamic analysis. Four types of structures were examined to bring comprehensive results.Regarding the importance of the optimized and economical design of structures, reducing the total weight of structures has been considered. This approach leads to a decrease in the cost of building projects. In another point of view, reducing the weight of structures will be associated with decreasing the dimension of different elements so it can increase the likelihood of strength failure in the structures. This paper intends to apply the soft computing technique, firstly, to bring a new algorithm for minimizing the weight of structures with respect to satisfying different technical constraints and secondly, to improve the speed of answer. To achieve the second goal, various methods including the modified genetic algorithm, the modified ant colony, and artificial neural network, were applied and tested. Some performance indicators such as speed of answer, accuracy, etc. were selected to compare the output of those mentioned approaches with traditional calculations. The obtained results showed that the modified ant colony algorithm has better performance in terms of speed of answer and accuracy. While several previous investigations have been looked at the problem of structure weight optimization from a two-dimensional perspective, this paper developed three-dimensional modeling by applying the spectrum dynamic analysis. Four types of structures were examined to bring comprehensive results.Amirkabir University of TechnologyAmirkabir Journal of Civil Engineering2588-297X52420200621A New Failure Criteria for Hollow-bar Micropile Based on Full-Scale Static Load
TestsA New Failure Criteria for Hollow-bar Micropile Based on Full-Scale Static Load
Tests919934318010.22060/ceej.2018.15093.5827FAMohammadaliFakharniaDepartment of civil engineering, University of Qom, Qom, IranHamedBayestehDepartment of civil engineering, university of QomJournal Article20181005Recently, the use of hollow-bar micropiles has increased rapidly. These micropiles reduce the time and cost and not only were used as a reinforcement element but also used to improve the surrounding soils. Despite the increasing use, few studies have been conducted on the performance of this type of micropiles, in particular the determination of load capacity, failure criteria, and interpretation of loading tests. In this study, 22 hollow bar micropiles with simultaneous injection methods in different lengths and soils were executed and full-scale tension and compression loading tests were performed on them. Then, by using the six common failure criteria for pile foundation, the performance and ultimate load of these tests were evaluated. Using mathematical relations, assumptions about load-displacement curves and using numerical modeling of the observed load-displacement behavior, field test results have been developed to reach the geotechnical failure. The results show that since the diameter and bond strength of hollow bar micropiles is more than theoretical ones, the existing failure criteria are not suitable for interpretation of their load-deformation behavior. The existing failure criteria do not take into account the increase in the bond strength and the reduction of the elastic length. Based on the information obtained from the existing failure criteria and considering the effect of elastic shortening on the loading test results, a failure criterion has been proposed to determine the failure load of hollow bar micropile based on the Davison method.Recently, the use of hollow-bar micropiles has increased rapidly. These micropiles reduce the time and cost and not only were used as a reinforcement element but also used to improve the surrounding soils. Despite the increasing use, few studies have been conducted on the performance of this type of micropiles, in particular the determination of load capacity, failure criteria, and interpretation of loading tests. In this study, 22 hollow bar micropiles with simultaneous injection methods in different lengths and soils were executed and full-scale tension and compression loading tests were performed on them. Then, by using the six common failure criteria for pile foundation, the performance and ultimate load of these tests were evaluated. Using mathematical relations, assumptions about load-displacement curves and using numerical modeling of the observed load-displacement behavior, field test results have been developed to reach the geotechnical failure. The results show that since the diameter and bond strength of hollow bar micropiles is more than theoretical ones, the existing failure criteria are not suitable for interpretation of their load-deformation behavior. The existing failure criteria do not take into account the increase in the bond strength and the reduction of the elastic length. Based on the information obtained from the existing failure criteria and considering the effect of elastic shortening on the loading test results, a failure criterion has been proposed to determine the failure load of hollow bar micropile based on the Davison method.Amirkabir University of TechnologyAmirkabir Journal of Civil Engineering2588-297X52420200621Laboratory study on stabilization of kaolinite clay with cement and cement kiln dustLaboratory study on stabilization of kaolinite clay with cement and cement kiln dust935948318510.22060/ceej.2018.15100.5829FASadeghGhavamiPhD candidate, School of Civil Engineering, Iran University of Science and Technology, Tehran, Iran.0000-0001-5102-7658HamidJahanbakhshPhD Student, Department of Civil Engineering and Environmental, Amirkabir University of Technology, Tehran, Iran.FereydoonMoghaddasnezhad0000-0003-3830-4555Journal Article20181007Considering the geotechnical problems caused by low strength, clayey soils are important in construction projects. Chemical stabilization with additives such as cement is a common method to improve the engineering properties of clay soils. In spite of the acceptable effects of cement on the strength of soils, the cost of this additive and its destructive effects on the environment should be of concern. This has led the researchers to use by-products and waste materials. Cement Kiln Dust (CKD) is a powdery byproduct of the Portland cement manufacturing process. In this paper, the geotechnical parameters of cement and cement kiln dust stabilized kaolinite clay are compared. For this purpose, Atterberg limits, standard proctor, unconfined compressive strength, and California bearing ratio tests were conducted on specimens containing 5, 10 and 15% cement and CKD (by dry weight of the soil). The results show that the cement and cement kiln dust increase soil strength. It was seen that the unconfined compressive strength of the specimen with 15% CKD is equal to the specimen with 10% cement after 28 days of curing. It is evident from the scanning electron microscopy analysis of specimens containing cement and CKD that calcium silicate and aluminate hydration products reduce the volume of the void spaces and join the soil particles, leading the strength to increase.Considering the geotechnical problems caused by low strength, clayey soils are important in construction projects. Chemical stabilization with additives such as cement is a common method to improve the engineering properties of clay soils. In spite of the acceptable effects of cement on the strength of soils, the cost of this additive and its destructive effects on the environment should be of concern. This has led the researchers to use by-products and waste materials. Cement Kiln Dust (CKD) is a powdery byproduct of the Portland cement manufacturing process. In this paper, the geotechnical parameters of cement and cement kiln dust stabilized kaolinite clay are compared. For this purpose, Atterberg limits, standard proctor, unconfined compressive strength, and California bearing ratio tests were conducted on specimens containing 5, 10 and 15% cement and CKD (by dry weight of the soil). The results show that the cement and cement kiln dust increase soil strength. It was seen that the unconfined compressive strength of the specimen with 15% CKD is equal to the specimen with 10% cement after 28 days of curing. It is evident from the scanning electron microscopy analysis of specimens containing cement and CKD that calcium silicate and aluminate hydration products reduce the volume of the void spaces and join the soil particles, leading the strength to increase.Amirkabir University of TechnologyAmirkabir Journal of Civil Engineering2588-297X52420200621Laboratory study of shear strength of loose sand in the case of Individual stone
columns, Equivalent trench, and Equivalent area methodLaboratory study of shear strength of loose sand in the case of Individual stone
columns, Equivalent trench, and Equivalent area method949968322010.22060/ceej.2019.15104.5830FAMajidAslaniDepartment of Civil Engineering, Lenjan Branch, Islamic Azad University, Isfahan, Iran0000-0001-7339-6040JavadNazariafsharAssistant Professor, Department of Civil Engineering, Shahr-e-Qods Branch
Islamic Azad University, Tehran, Iran0000-0001-8807-1417Journal Article20181007Due to the complexity of a three-dimensional (3-D) arrangement of multiple columns, a 3-D problem has been commonly converted into a two-dimensional (2-D) model, which has equivalent properties and dimensions by the equivalent trench method and the equivalent area method. These methods are used extensively in analytical and numerical studies. However, no comparison of the results of the above methods and laboratory studies has been done. Therefore, in this research, the experiments performed on reinforced soil in a large direct shear device with dimensions of 305×305×152 mm3. Experiments performed with individual stone columns (single, square and triangular arrangement), equivalent trench and equivalent area method. The effective parameters include the area replacement ratio, 8.4,12, 16.4 and 25 percent, and vertical loads (55, 75 and 100 kPa) Has been studied. Results showed that improves the stiffness of composite soils and increase in shear strength of individual stone columns (single, square and triangular arrangement) and equivalent trench and stone column arrangement had an impact on improving the shear strength of stone columns. The most increase in shear strength and stiffness values was observed for square arrangement of stone columns and the least increase was for single stone columns. Comparing the results of individual stone columns and equivalent trench in any arrangement, showed that equivalent trench arrangement could be used in two-dimensional models instead of three-dimensional individual stone columns. In the equivalent area method, there is no increase in shear strength and shear strength parameters compared to sandy bed.Due to the complexity of a three-dimensional (3-D) arrangement of multiple columns, a 3-D problem has been commonly converted into a two-dimensional (2-D) model, which has equivalent properties and dimensions by the equivalent trench method and the equivalent area method. These methods are used extensively in analytical and numerical studies. However, no comparison of the results of the above methods and laboratory studies has been done. Therefore, in this research, the experiments performed on reinforced soil in a large direct shear device with dimensions of 305×305×152 mm3. Experiments performed with individual stone columns (single, square and triangular arrangement), equivalent trench and equivalent area method. The effective parameters include the area replacement ratio, 8.4,12, 16.4 and 25 percent, and vertical loads (55, 75 and 100 kPa) Has been studied. Results showed that improves the stiffness of composite soils and increase in shear strength of individual stone columns (single, square and triangular arrangement) and equivalent trench and stone column arrangement had an impact on improving the shear strength of stone columns. The most increase in shear strength and stiffness values was observed for square arrangement of stone columns and the least increase was for single stone columns. Comparing the results of individual stone columns and equivalent trench in any arrangement, showed that equivalent trench arrangement could be used in two-dimensional models instead of three-dimensional individual stone columns. In the equivalent area method, there is no increase in shear strength and shear strength parameters compared to sandy bed.Amirkabir University of TechnologyAmirkabir Journal of Civil Engineering2588-297X52420200621Numerical Simulation of Sub-Surface Landslide Waves Using an explicit three-step
compressible SPH algorithmNumerical Simulation of Sub-Surface Landslide Waves Using an explicit three-step
compressible SPH algorithm969988322710.22060/ceej.2019.15114.5831FASeyed ErfanHosseini MobaraWater engineering group, Water engineering college, Razi university, kermanshah,Iran0000-0002-4465-583XRasoolGhobadianWater engineering group, Water engineering college, Razi university, kermanshah,IranJournal Article20181010The coastal waves that are produced by a landslide in the lake of reservoir dams can threaten the dam safety. Therefore, the exact recognition of hydraulic flow due to coastal waves has always been of interest to researchers. So far, extensive laboratory and numerical research have been conducted. In this research, a completely lagrangian numerical method which is based on particle and non-grid called the Smoothed Particle Hydrodynamic Method (SPH) was used to simulate coastal waves due to landslide. In the present study, a new three-step SPH algorithm based on the prediction and correction method was solved by governing equations. To validate the method, the laboratory data of the dam break problem on dry bed has been used. The results of this study approximated the analytical solution well, and the current model result was close to the analytical solution for the depth of flow in the break site. Also, the correlation coefficient of 0.9998, the mean absolute error of 0.5426 and the efficiency coefficient of the Nash-Sutcliff model 0.974 for the calculated parameters indicated that the model is accurately calibrated and the model can simulate the depth and discharge of water. Also, the results showed that the ability of the present model in the numerical simulation of sub-surface landslide wave in the production region and run-up region is high, and it stimulates the propagation region very well with an accuracy of 95%. With the comparison of measured and laboratory results, the correlation coefficient and the root mean square error were 0.95 and 0.0071 respectively, which indicates the high accuracy of the model in calculating the surface water profile due to subsurface landslide.The coastal waves that are produced by a landslide in the lake of reservoir dams can threaten the dam safety. Therefore, the exact recognition of hydraulic flow due to coastal waves has always been of interest to researchers. So far, extensive laboratory and numerical research have been conducted. In this research, a completely lagrangian numerical method which is based on particle and non-grid called the Smoothed Particle Hydrodynamic Method (SPH) was used to simulate coastal waves due to landslide. In the present study, a new three-step SPH algorithm based on the prediction and correction method was solved by governing equations. To validate the method, the laboratory data of the dam break problem on dry bed has been used. The results of this study approximated the analytical solution well, and the current model result was close to the analytical solution for the depth of flow in the break site. Also, the correlation coefficient of 0.9998, the mean absolute error of 0.5426 and the efficiency coefficient of the Nash-Sutcliff model 0.974 for the calculated parameters indicated that the model is accurately calibrated and the model can simulate the depth and discharge of water. Also, the results showed that the ability of the present model in the numerical simulation of sub-surface landslide wave in the production region and run-up region is high, and it stimulates the propagation region very well with an accuracy of 95%. With the comparison of measured and laboratory results, the correlation coefficient and the root mean square error were 0.95 and 0.0071 respectively, which indicates the high accuracy of the model in calculating the surface water profile due to subsurface landslide.Amirkabir University of TechnologyAmirkabir Journal of Civil Engineering2588-297X52420200621Evaluation of the vegetable mulch produced from Eremurus spectabilis on soil erosion
controlEvaluation of the vegetable mulch produced from Eremurus spectabilis on soil erosion
control9891008320610.22060/ceej.2018.15149.5839FAAmirAmraeidepartment of water and environmental engineering, faculty of civil engineering, shahrood university of technology, shahrood, iranBehnazDahrazmadepartment of water and environmental engineering, faculty of civil engineering, shahrood university of technology, shahrood, iran0000-0002-9851-0361Journal Article20181019One of the main challenges of arid and desert regions is to control wind erosion that can cause significant economic and environmental damage. The present study aimed to stabilize erosionprone soil using a vegetable mulch prepared from Eremurus spectabilis root powder. The effects of concentration and amount of mulch spraying on the soil erosion were investigated. Also, the penetration and reduction of the thickness of the fixed layer against wind speeds of 6, 9, 12 and 15 m/s for 5 minutes were studied in the wind tunnel. Finally, EC, pH, salinity and other soil elements were tested to evaluate the environmental impact of mulching. The results showed that increasing the amount of mulch spraying results in more mulch penetration in the soil and increasing the mulch concentration, despite reducing the depth of its penetration into the soil due to increasing the amount of adhesion between the soil particles, its greater resistance to wind erosion. In addition, based on the results, mulches with concentrations of 0.2, 0.6 and 0.7% can stabilize the soil against the wind stream, up to a maximum of 9, 12 and 15 m/s, respectively. Generally, the mulch is environmentally friendly and is an appropriate option for controlling the erosion of wind erosion-prone soil.One of the main challenges of arid and desert regions is to control wind erosion that can cause significant economic and environmental damage. The present study aimed to stabilize erosionprone soil using a vegetable mulch prepared from Eremurus spectabilis root powder. The effects of concentration and amount of mulch spraying on the soil erosion were investigated. Also, the penetration and reduction of the thickness of the fixed layer against wind speeds of 6, 9, 12 and 15 m/s for 5 minutes were studied in the wind tunnel. Finally, EC, pH, salinity and other soil elements were tested to evaluate the environmental impact of mulching. The results showed that increasing the amount of mulch spraying results in more mulch penetration in the soil and increasing the mulch concentration, despite reducing the depth of its penetration into the soil due to increasing the amount of adhesion between the soil particles, its greater resistance to wind erosion. In addition, based on the results, mulches with concentrations of 0.2, 0.6 and 0.7% can stabilize the soil against the wind stream, up to a maximum of 9, 12 and 15 m/s, respectively. Generally, the mulch is environmentally friendly and is an appropriate option for controlling the erosion of wind erosion-prone soil.Amirkabir University of TechnologyAmirkabir Journal of Civil Engineering2588-297X52420200621Application of MQ-RBF method for solving seepage problems with a new algorithm
for optimization of the shape parameterApplication of MQ-RBF method for solving seepage problems with a new algorithm
for optimization of the shape parameter10091024322210.22060/ceej.2019.15155.5840FAMasoumehKoushkiUniversity of QomRezaBabaeeUniversity of QomEhsanJabbariUniversity of Qom0000-0002-6345-8567Journal Article20181019The accuracy of the meshless method, Multiquadric, depends completely on the choice of its optimal shape parameter. The purpose of this research is proposing a new algorithm for determining the optimal shape parameter. It resolves some of the previous difficulties, such as depending on the number of computational nodes or an exact solution of the problem, high cost and low accuracy of calculations, being experimental, convergence of classical optimization methods to local optimal points and so on. For this purpose, in addition to introducing a new objective function, Genetic Algorithm(GA) was used and for speeding up the process of its solution, lower bound and upper bound of the shape parameter are suggested as minimum (when the coefficient matrix is not singular) and maximum radius of computational nodes, respectively. The algorithm consists of four steps: 1) producing initial shape parameters by GA in the proposed range, 2) introducing the MQ function with a few numbers of computational points, 3) introducing the MQ function with a large number of computational points, and 4) minimizing the difference between solutions of two functions obtained from the two preceding steps. In the meta-heuristic algorithm, uniform and non-uniform regular distributions of computational nodes have been successfully applied and it was shown that with this approach, an optimal constant shape parameter independent of the number of computational points could be obtained for arbitrary geometries. For verification, examples of homogeneous, inhomogeneous and anisotropic types of the seepage phenomena were solved so that domain decomposition technique was used for inhomogeneous problems and complex geometries. A comparison of results with other exact and numerical solutions showed the high ability and accuracy of the proposed algorithm.The accuracy of the meshless method, Multiquadric, depends completely on the choice of its optimal shape parameter. The purpose of this research is proposing a new algorithm for determining the optimal shape parameter. It resolves some of the previous difficulties, such as depending on the number of computational nodes or an exact solution of the problem, high cost and low accuracy of calculations, being experimental, convergence of classical optimization methods to local optimal points and so on. For this purpose, in addition to introducing a new objective function, Genetic Algorithm(GA) was used and for speeding up the process of its solution, lower bound and upper bound of the shape parameter are suggested as minimum (when the coefficient matrix is not singular) and maximum radius of computational nodes, respectively. The algorithm consists of four steps: 1) producing initial shape parameters by GA in the proposed range, 2) introducing the MQ function with a few numbers of computational points, 3) introducing the MQ function with a large number of computational points, and 4) minimizing the difference between solutions of two functions obtained from the two preceding steps. In the meta-heuristic algorithm, uniform and non-uniform regular distributions of computational nodes have been successfully applied and it was shown that with this approach, an optimal constant shape parameter independent of the number of computational points could be obtained for arbitrary geometries. For verification, examples of homogeneous, inhomogeneous and anisotropic types of the seepage phenomena were solved so that domain decomposition technique was used for inhomogeneous problems and complex geometries. A comparison of results with other exact and numerical solutions showed the high ability and accuracy of the proposed algorithm.