Amirkabir University of TechnologyAmirkabir Journal of Civil Engineering2588-297X521020201221A relationship to estimate the optimal drilling mud pressure in oil wells in carbonate formations of southern Iran oil fieldsA relationship to estimate the optimal drilling mud pressure in oil wells in carbonate formations of southern Iran oil fields24012414349810.22060/ceej.2019.16129.6135FANaserBehnamImam Khomeini international universityMehdiHosseiniImam Khomeini international universitySinaShahbaziImam Khomeini international universityJournal Article20190414The analysis and prediction of well wall stability is considered as one of the most important and critical points in drilling operations. The instability of the well wall is one of the most serious problems in the oil and gas well drilling industry because it can lead to loss of part of the well or its entirety, which ultimately results in delays in operations, increased costs Drilling and delay will occur at the time of operation. One of the most important ways to cope with this problem is to determine the optimal drilling mud pressure. The pressure of the mud should be so high that it is in proportion to the amount of tension in the pores and pockets, and to the extent that the well after the large tensile fractures caused by the high pressure of the mud, as well as the shear fractures due to low pressure It will be safe. The aim of this study was to obtain a relationship to estimate the optimal drilling mud pressure in wells in the oil-rich regions of southern Iran. To achieve this goal, information of a number of oil wells was collected in the oil fields of southern Iran and then, using FLAC2D software, a limited-scale numerical program limited to oil wells, oil wells were analyzed in two Equilibriums and equilibriums modes have been investigated. Ultimately, for determination of the stability of the optimum drilling mud in the elastoplastic method, the method of determining the normalized level of NYZA has been used. In each step, optimal drilling mud pressure is calculated and finally, a correlation is presented using SPSS software through multivariate linear regression. This relationship is a linear relationship in which the optimal drilling mud pressure is estimated by parameters of minimum and maximum horizontal tensions, pore pressure, internal friction angle and cohesion.The analysis and prediction of well wall stability is considered as one of the most important and critical points in drilling operations. The instability of the well wall is one of the most serious problems in the oil and gas well drilling industry because it can lead to loss of part of the well or its entirety, which ultimately results in delays in operations, increased costs Drilling and delay will occur at the time of operation. One of the most important ways to cope with this problem is to determine the optimal drilling mud pressure. The pressure of the mud should be so high that it is in proportion to the amount of tension in the pores and pockets, and to the extent that the well after the large tensile fractures caused by the high pressure of the mud, as well as the shear fractures due to low pressure It will be safe. The aim of this study was to obtain a relationship to estimate the optimal drilling mud pressure in wells in the oil-rich regions of southern Iran. To achieve this goal, information of a number of oil wells was collected in the oil fields of southern Iran and then, using FLAC2D software, a limited-scale numerical program limited to oil wells, oil wells were analyzed in two Equilibriums and equilibriums modes have been investigated. Ultimately, for determination of the stability of the optimum drilling mud in the elastoplastic method, the method of determining the normalized level of NYZA has been used. In each step, optimal drilling mud pressure is calculated and finally, a correlation is presented using SPSS software through multivariate linear regression. This relationship is a linear relationship in which the optimal drilling mud pressure is estimated by parameters of minimum and maximum horizontal tensions, pore pressure, internal friction angle and cohesion.Amirkabir University of TechnologyAmirkabir Journal of Civil Engineering2588-297X521020201221Energy Balance on Steel Structure with Pall Damper under Blast LoadingEnergy Balance on Steel Structure with Pall Damper under Blast Loading24152434351510.22060/ceej.2019.16340.6192FAMajidMoradiBabol Noshirvani University of TechnologyHamidrezaTavakoliBabol Noshirvani University of Technology0000-0001-5298-6199Journal Article20190514Plenty of factors produce the input energy to a structure. Earthquakes and Blats each one induces an energy to the structure and it must balance between input energy and the cumulative internal energies; otherwise, damage will happen in the structure. Blast is one of the rare occurrences that can happen in the life time of a building. The number of explosive attacks on civilian structures has recently increased. Energy absorbers have being paid attention in order to control the vibrations. One of these energy absorbers is Pall damper. Considering the essence of Blast, which is the result of releasing energy, and the basis of energy absorbers which plays the role of getting the input energy of the structure, investigating the energy balance in structures having energy absorbers can help us understand the behavior of structures under Blast loads truly. Thus, in this study, it is tried to focus on the behavior of steel structures having Pall friction damper under various Blast loading, by use of energy balance concepts.Plenty of factors produce the input energy to a structure. Earthquakes and Blats each one induces an energy to the structure and it must balance between input energy and the cumulative internal energies; otherwise, damage will happen in the structure. Blast is one of the rare occurrences that can happen in the life time of a building. The number of explosive attacks on civilian structures has recently increased. Energy absorbers have being paid attention in order to control the vibrations. One of these energy absorbers is Pall damper. Considering the essence of Blast, which is the result of releasing energy, and the basis of energy absorbers which plays the role of getting the input energy of the structure, investigating the energy balance in structures having energy absorbers can help us understand the behavior of structures under Blast loads truly. Thus, in this study, it is tried to focus on the behavior of steel structures having Pall friction damper under various Blast loading, by use of energy balance concepts.Amirkabir University of TechnologyAmirkabir Journal of Civil Engineering2588-297X521020201221Behavior Study of the Gypsiferous Sand Soil of AlNajaf City with Presence of Matric Suction Using Unsaturated Triaxial DeviceBehavior Study of the Gypsiferous Sand Soil of AlNajaf City with Presence of Matric Suction Using Unsaturated Triaxial Device24352450351910.22060/ceej.2019.16339.6194FAMustafaAbdalhuseinCivil Engineering Department, Engineering Faculty, Ferdowsi University of Mashhad, IranAliAkhtarpourCivil Engineering Department, Engineering Faculty, Ferdowsi University of mashhad,Mashhad,IranMohammedMahmoodCivil Engineering Department, Engineering Faculty, Kufa University, IraqJournal Article20190515Al-Najaf city is considered one of the gypsiferous rich soils cities in Iraq. When a building is constructed on a gypsiferous soil in the unsaturated state, no effective settlement will be distinguished. When a gradual saturation has occurred, the soil gives a clear deformation and may be collapsed. This paper presents how the degree of saturation can affect on the deformation of a gypsum sand soil. A triaxial test device has been modified to have the ability for unsaturated tests. The soil samples were taken from Al-Najaf city in Iraq. Disturbed samples with two different gypsum contents; 14% and 29%, are tested with the presence of different matric suctions, initial matric suction, 60% initial matric suction, 30% initial matric suction and zero matric suction. A loading-path was adopted to symbolize when construction is built on a gypsiferous sand soil in a specific matric suction (specific degree of saturation). In addition to the previous tests, two conventional saturated tests (CD) were added under the above mentioned of confining stresses. The results were when increasing matric suction, the stiffness and shear strength are reduced and the volumetric strains increase significantly. The percentage increases are 60% and 50% under confining pressure of 100 kPa and 200 kPa, respectively for the two selected gypsum contents. The results of this study can be used to estimate the settlement that results from decreasing matric suction due to water table rise or other phenomena.Al-Najaf city is considered one of the gypsiferous rich soils cities in Iraq. When a building is constructed on a gypsiferous soil in the unsaturated state, no effective settlement will be distinguished. When a gradual saturation has occurred, the soil gives a clear deformation and may be collapsed. This paper presents how the degree of saturation can affect on the deformation of a gypsum sand soil. A triaxial test device has been modified to have the ability for unsaturated tests. The soil samples were taken from Al-Najaf city in Iraq. Disturbed samples with two different gypsum contents; 14% and 29%, are tested with the presence of different matric suctions, initial matric suction, 60% initial matric suction, 30% initial matric suction and zero matric suction. A loading-path was adopted to symbolize when construction is built on a gypsiferous sand soil in a specific matric suction (specific degree of saturation). In addition to the previous tests, two conventional saturated tests (CD) were added under the above mentioned of confining stresses. The results were when increasing matric suction, the stiffness and shear strength are reduced and the volumetric strains increase significantly. The percentage increases are 60% and 50% under confining pressure of 100 kPa and 200 kPa, respectively for the two selected gypsum contents. The results of this study can be used to estimate the settlement that results from decreasing matric suction due to water table rise or other phenomena.Amirkabir University of TechnologyAmirkabir Journal of Civil Engineering2588-297X521020201221Reliability analysis for static stability of reinforced soilReliability analysis for static stability of reinforced soil24512470351710.22060/ceej.2019.16349.6197FANaserShabakhtyIran University of Science & TechnologySaeedGhaffarpour JahromiShahid Rajaee Teacher Training University0000-0002-3033-7195RebinAhmadiShahid Rajaee Teacher Training UniversityJournal Article20190517 In this study the stability of the flexible walls and the type of reinforced soil walls are evaluated to examine the stability and design the retaining walls with reliability method which gives more realistic results than other design methods. In this paper, using related softwares the effect of various parameters such as internal friction angle, soil specific gravity, reinforcement resistance, friction angle between the soil and the retaining wall, load, assuming uncertainty in the parameters and also the investigation the correlation of parameters will be investigated on the stability of reinforces soil walls after analyzing and determining the effective parameters among these parameters, we will analysis the sensitivity of these parameters to see which of these parameters has more influence on the stability of reinforces soil walls. Two types of stability are considered in reinforces soil walls which include external stability and internal stability. In this study the stability of the flexible walls and the type of reinforced soil walls are evaluated to examine the stability and design the retaining walls with reliability method which gives more realistic results than other design methods. In this paper, using related softwares the effect of various parameters such as internal friction angle, soil specific gravity, reinforcement resistance, friction angle between the soil and the retaining wall, load, assuming uncertainty in the parameters and also the investigation the correlation of parameters will be investigated on the stability of reinforces soil walls after analyzing and determining the effective parameters among these parameters, we will analysis the sensitivity of these parameters to see which of these parameters has more influence on the stability of reinforces soil walls. Two types of stability are considered in reinforces soil walls which include external stability and internal stability.Amirkabir University of TechnologyAmirkabir Journal of Civil Engineering2588-297X521020201221Effect of natural Basalt fibers on mechanical properties of clay Rey townEffect of natural Basalt fibers on mechanical properties of clay Rey town24712486351410.22060/ceej.2019.16360.6199FANastaranKhorramMsc Student, Geotechnic Engineer, University of QomAli M.RajabiFaculty member, Engineering Geology, Tehran UniversityJournal Article20190518A mechanical method for soil stabilization is the use of reinforcing elements such as geotextiles, geogrids and natural or artificial fibers. A new type of fiber that has a natural origin and its production and application has the least environmental impact is basalt fiber. In this study, in addition to index tests, a series of experiments including modified Proctor compaction test, uniaxial compressive strength test and indirect tensile strength test and SEM electron microscopy on stabilized clay with Basalt fibers with random distribution were carried out. The focus of this research was mainly on the effect of fibers length and weight percentage on soil resistance parameters. For this purpose, basalt fibers were mixed with soil in weight percentages of 0.25, 0.5, 0.75, 1, 1.5, 2 and with three different lengths of 6, 12, 25 mm, then compressed with optimum moisture content.A mechanical method for soil stabilization is the use of reinforcing elements such as geotextiles, geogrids and natural or artificial fibers. A new type of fiber that has a natural origin and its production and application has the least environmental impact is basalt fiber. In this study, in addition to index tests, a series of experiments including modified Proctor compaction test, uniaxial compressive strength test and indirect tensile strength test and SEM electron microscopy on stabilized clay with Basalt fibers with random distribution were carried out. The focus of this research was mainly on the effect of fibers length and weight percentage on soil resistance parameters. For this purpose, basalt fibers were mixed with soil in weight percentages of 0.25, 0.5, 0.75, 1, 1.5, 2 and with three different lengths of 6, 12, 25 mm, then compressed with optimum moisture content.Amirkabir University of TechnologyAmirkabir Journal of Civil Engineering2588-297X521020201221Experimental investigating on hydraulic parameters of vertical drop equipped with combined screensExperimental investigating on hydraulic parameters of vertical drop equipped with combined screens24872500350510.22060/ceej.2019.16431.6223FAVadoudHasanniaM.Sc. in Civil Engineering-Hydraulic Structures, Department of Civil Engineering, Faculty of Engineering, University of Maragheh, Maragheh, Iran.RasoulDaneshfarazAssociate Professor, Department of Civil Engineering, Faculty of Engineering, University of Maragheh, Maragheh, Iran.0000-0003-1012-8342SinaSadeghfamAssistant Professor, Department of Civil Engineering, Faculty of Engineering, University of Maragheh, Maragheh, Iran.0000-0002-9018-547XJournal Article20190527In many overflow structures such as vertical drops, using the flow energy dissipator and investigating the subsequent effect on the hydraulic parameters are the most important issues in hydraulics. This study experimentally investigates the behavior of hydraulic parameters through the utilization of combined screens (horizontal-vertical) in vertical drops. The results revealed that the utilization of the screens combined with vertical drops reduces the relative mixing length and increases the relative pool depth and relative energy loss with respect to a plain vertical drop. It was also observed that the increase in the relative critical depth result in the increase in the relative wetted length of the vertical screens, the relative mixing length and the relative pool depth, and decrease in the relative energy loss. Evaluating the total energy dissipation of system by the effective components of energy dissipation exhibited that, by increasing relative critical depth, the performance of vertical drop equipped with horizontal screen decreases and the performance of vertical screen increases. However, the contribution of vertical drop equipped with a horizontal screen is more than 82% of the total energy loss of the system. Also, increasing the porosity of screen reduces the relative wetted length of horizontal and vertical screens, the relative mixing length and relative pool depth, and increase the relative energy loss.In many overflow structures such as vertical drops, using the flow energy dissipator and investigating the subsequent effect on the hydraulic parameters are the most important issues in hydraulics. This study experimentally investigates the behavior of hydraulic parameters through the utilization of combined screens (horizontal-vertical) in vertical drops. The results revealed that the utilization of the screens combined with vertical drops reduces the relative mixing length and increases the relative pool depth and relative energy loss with respect to a plain vertical drop. It was also observed that the increase in the relative critical depth result in the increase in the relative wetted length of the vertical screens, the relative mixing length and the relative pool depth, and decrease in the relative energy loss. Evaluating the total energy dissipation of system by the effective components of energy dissipation exhibited that, by increasing relative critical depth, the performance of vertical drop equipped with horizontal screen decreases and the performance of vertical screen increases. However, the contribution of vertical drop equipped with a horizontal screen is more than 82% of the total energy loss of the system. Also, increasing the porosity of screen reduces the relative wetted length of horizontal and vertical screens, the relative mixing length and relative pool depth, and increase the relative energy loss.Amirkabir University of TechnologyAmirkabir Journal of Civil Engineering2588-297X521020201221Height effect on shear strength of deep beams without Shear Reinforcement with normal and lightweight concreteHeight effect on shear strength of deep beams without Shear Reinforcement with normal and lightweight concrete25012514327810.22060/ceej.2019.8777.4779FAAbolfazlArabzadeAminNooriJournal Article20140909Failure in reinforced concrete deep beams is mainly in shear and in a brittle and sudden form, which this behavior can lead to destructive consequences. So determining shear capacity of these beams is an important issue. One of major parameters in determining shear capacity of beams is the height of beam. Researches show that with increase in beam’s height, normalized shear strength decreases which this phenomena is called size effect. In recent years due to advances in construction methods, the idea of using lightweight concrete deep beams has been proposed, this should be done with a full understanding of the behavior of lightweight concrete. Moreover, truss models are recently used for analysis and design of deep beams in codes which their validity for lightweight concrete should be investigated. In this research to investigating size effect in lightweight concrete deep beams and comparison with normal concrete, two series of beams including 8 deep beam with shear span to height ratio of 0.5 were built in lab. First series included 4 beams with height of 30, 45, 60 and 90 cm using lightweight concrete in their construction, specimens of second series were similar to first but normal concrete was used in there construction. Results show that failure mode is independent of height and concrete type. The pattern of crack propagation is more affected by height and almost independent of concrete type. Normalized shear strength in both groups of beams decreases with increase in height but the intensity of this decrease in lightweight concrete deep beams is more than normal concrete which shows that size effect in lightweight concrete is more than normal concrete. Results of Experiment were compared to truss methods in codes and some of proposed models in codes. Results indicate that all methods are conservative in low height beams and with increase in height, safety margin decreases. Results of CSA code is non-conservative for beams with 90 cm height which needs more study.Failure in reinforced concrete deep beams is mainly in shear and in a brittle and sudden form, which this behavior can lead to destructive consequences. So determining shear capacity of these beams is an important issue. One of major parameters in determining shear capacity of beams is the height of beam. Researches show that with increase in beam’s height, normalized shear strength decreases which this phenomena is called size effect. In recent years due to advances in construction methods, the idea of using lightweight concrete deep beams has been proposed, this should be done with a full understanding of the behavior of lightweight concrete. Moreover, truss models are recently used for analysis and design of deep beams in codes which their validity for lightweight concrete should be investigated. In this research to investigating size effect in lightweight concrete deep beams and comparison with normal concrete, two series of beams including 8 deep beam with shear span to height ratio of 0.5 were built in lab. First series included 4 beams with height of 30, 45, 60 and 90 cm using lightweight concrete in their construction, specimens of second series were similar to first but normal concrete was used in there construction. Results show that failure mode is independent of height and concrete type. The pattern of crack propagation is more affected by height and almost independent of concrete type. Normalized shear strength in both groups of beams decreases with increase in height but the intensity of this decrease in lightweight concrete deep beams is more than normal concrete which shows that size effect in lightweight concrete is more than normal concrete. Results of Experiment were compared to truss methods in codes and some of proposed models in codes. Results indicate that all methods are conservative in low height beams and with increase in height, safety margin decreases. Results of CSA code is non-conservative for beams with 90 cm height which needs more study.Amirkabir University of TechnologyAmirkabir Journal of Civil Engineering2588-297X521020201221Evaluation of Reduction Factor for concrete coatings of underground structures under blast loadingEvaluation of Reduction Factor for concrete coatings of underground structures under blast loading25152528362510.22060/ceej.2019.14735.5733FASafaPeymanSchool of Civil Engineering, Imam Hossein University, Tehran, IranMohammad HosseinTaghavi ParsaIHU,QOM ac0000-0002-2968-7294AminBabaieدانشگاه امام حسین علیه السلامAhmadAkbarisahel ConsultingJournal Article20180725The reduction factor (R) is one of the most important parameter of loading, analyzing and designing structures subjected to dynamic loading such as earthquake and explosion. This coefficient considers the nonlinear behavior of the structure in linear analysis. Investigations show that the acceptable range for reduction factor of concrete coating of underground structures applied to explosive loading is not determined completely. To find out this factor, the tunnel structure must first be modeled numerically. The interaction between the structure and the soil and their mechanical properties should be modeled so Winkler spring was proposed. In this research, plastic hinges were introduced in the SAP2000 software, and a pushover analysis was carried out. Outputs of this analysis result in the vertical force-displacement diagrams and their behaviors were plotted for each tunnel performance levels. The Reduction Factor is obtained for a special pattern loading of explosive charge by using the relationships which is developed in this research. It can be noted that the reduction factor for such structures depends on two parameters including ductility and strength factorThe reduction factor (R) is one of the most important parameter of loading, analyzing and designing structures subjected to dynamic loading such as earthquake and explosion. This coefficient considers the nonlinear behavior of the structure in linear analysis. Investigations show that the acceptable range for reduction factor of concrete coating of underground structures applied to explosive loading is not determined completely. To find out this factor, the tunnel structure must first be modeled numerically. The interaction between the structure and the soil and their mechanical properties should be modeled so Winkler spring was proposed. In this research, plastic hinges were introduced in the SAP2000 software, and a pushover analysis was carried out. Outputs of this analysis result in the vertical force-displacement diagrams and their behaviors were plotted for each tunnel performance levels. The Reduction Factor is obtained for a special pattern loading of explosive charge by using the relationships which is developed in this research. It can be noted that the reduction factor for such structures depends on two parameters including ductility and strength factorAmirkabir University of TechnologyAmirkabir Journal of Civil Engineering2588-297X521020201221Physical modeling for evaluating the effect of helical anchor configuration and surcharge on wall displacementPhysical modeling for evaluating the effect of helical anchor configuration and surcharge on wall displacement25292548353010.22060/ceej.2019.15447.5922FAJavadNazariafsharAssistant Professor, Department of Civil Engineering, Shahr-e-Qods Branch
Islamic Azad University, Tehran, Iran0000-0001-8807-1417Mohammad EmadMahmoudi MehriziCampus international of Kharazmi University, Tehran, IranYounosDaghighAssisstant professor in department of Civil Engineeering, Islamic Azad University- Karaj, IranJournal Article20181215 Helical anchors with unique characteristics have several applications in constructing and reforming the foundations, as well as soil improvement. However, a limited number of study has been done on the use of helical anchors in walls and slopes stability. In the performed studies, the behavior of the helical anchor’s wall was investigated. For this purpose, a laboratory study was designed to evaluate the wall stability with three types of helical anchors and two types of back-slopes in sandy soil. The aim of the study was to investigate the effect of anchor’s shape and the back slope above the wall on the wall crest displacement. To increase the accuracy of measurements and determine the shear strains, photogrammetry and particle image velocimetry (PIV) methods were employed. Finally, to evaluate its implementation potential, the results were compared with those of the nailing method. The results of modeling revealed that an increase in diameter and the number of the helices led to decreasing in wall crest displacement. The reduction percentages were 30% and 60% respectively for increased diameter and increased number of helices and diameter. If the significant reduction in displacement is required, it is suggested to increase the number of helices without any changes in their diameter. Besides, anchors need a small amount of displacement to be activated and this issue cannot be solved by changing the type of helical anchor. Finally, the results indicated that the slip surface created on the wall of helical anchor using light surcharge is parabolic in shape. Helical anchors with unique characteristics have several applications in constructing and reforming the foundations, as well as soil improvement. However, a limited number of study has been done on the use of helical anchors in walls and slopes stability. In the performed studies, the behavior of the helical anchor’s wall was investigated. For this purpose, a laboratory study was designed to evaluate the wall stability with three types of helical anchors and two types of back-slopes in sandy soil. The aim of the study was to investigate the effect of anchor’s shape and the back slope above the wall on the wall crest displacement. To increase the accuracy of measurements and determine the shear strains, photogrammetry and particle image velocimetry (PIV) methods were employed. Finally, to evaluate its implementation potential, the results were compared with those of the nailing method. The results of modeling revealed that an increase in diameter and the number of the helices led to decreasing in wall crest displacement. The reduction percentages were 30% and 60% respectively for increased diameter and increased number of helices and diameter. If the significant reduction in displacement is required, it is suggested to increase the number of helices without any changes in their diameter. Besides, anchors need a small amount of displacement to be activated and this issue cannot be solved by changing the type of helical anchor. Finally, the results indicated that the slip surface created on the wall of helical anchor using light surcharge is parabolic in shape.Amirkabir University of TechnologyAmirkabir Journal of Civil Engineering2588-297X521020201221Study On Compressive Strength Of Micro-jet Grouting Columns By Physical ModelingStudy On Compressive Strength Of Micro-jet Grouting Columns By Physical Modeling25492562359710.22060/ceej.2019.15491.5932FASoheilSharifiDepartment of Civil Engineer, Science and Technology UniversityMohsenSabermahaniSchool of Civil Eng.; Iran University of Science and Technology; Tehran; Iran0000-0003-0430-6755Sayed RasoolSooraniDepartment of Civil Engineer, Science and Technology UniversityJournal Article20181223Jet grouting method is considered as one of the most widely used improvement methods among the others and is applicable in most geotechnical problems such as increasing bearing capacity, reducing settlement, creating seals, stabilizing slopes, etc. One of the challenges faced by designers is finding the strength and geometry of the elements made using this method. The most effective components in the resistance of jet grouting columns are the type and parameters of injection, soil characteristics (such as aggregation), the amount of cement inside the sample, water to cement ratio of slurry, the type of cement and the method of sampling (coring or wet sampling). In this paper, after the construction of small scale jet grouting columns (micro jet grouting volumns) in the laboratory and taking core of them, the impact of various factors such as the effect of construction speed, the position and direction of coring, as well as the effect of coring operation on unconfined compressive strength is studied. Also, the point load test was used to study more about the strength parameters of the microjet grouting columns. Based on the results, the compressive strength of microjet grouting columns is high (approximately up to 59 MPa), and these values are confirmed by the point load test. It was also observed that with increasing speed of soil-cement columns construction, compressive strength decreases. Based on the compressive strength results, it is found that coring operation reduces resistance by 60%. Also, the cores taken in the horizontal direction showed about 33% less uniaxial compressive strength than the vertical cores and cores taken from the upper parts of the columns have more compressive strength.Jet grouting method is considered as one of the most widely used improvement methods among the others and is applicable in most geotechnical problems such as increasing bearing capacity, reducing settlement, creating seals, stabilizing slopes, etc. One of the challenges faced by designers is finding the strength and geometry of the elements made using this method. The most effective components in the resistance of jet grouting columns are the type and parameters of injection, soil characteristics (such as aggregation), the amount of cement inside the sample, water to cement ratio of slurry, the type of cement and the method of sampling (coring or wet sampling). In this paper, after the construction of small scale jet grouting columns (micro jet grouting volumns) in the laboratory and taking core of them, the impact of various factors such as the effect of construction speed, the position and direction of coring, as well as the effect of coring operation on unconfined compressive strength is studied. Also, the point load test was used to study more about the strength parameters of the microjet grouting columns. Based on the results, the compressive strength of microjet grouting columns is high (approximately up to 59 MPa), and these values are confirmed by the point load test. It was also observed that with increasing speed of soil-cement columns construction, compressive strength decreases. Based on the compressive strength results, it is found that coring operation reduces resistance by 60%. Also, the cores taken in the horizontal direction showed about 33% less uniaxial compressive strength than the vertical cores and cores taken from the upper parts of the columns have more compressive strength.Amirkabir University of TechnologyAmirkabir Journal of Civil Engineering2588-297X521020201221Comparing performance of TMD and MTMD vertically distributed in height for multi-modal seismic control of tall buildingsComparing performance of TMD and MTMD vertically distributed in height for multi-modal seismic control of tall buildings25632582354010.22060/ceej.2019.15584.5959FAAliAkhlagh Pasandcivil engineering, school of civil engineering, university of Tehran, Tehran, Iran0000-0002-1067-4581AmirhoseinFatollah Pourcivil engineering, faculty of civil engineering, university of Zanjan, Zanjan, Iran0000-0002-2697-2065S. MehdiZahraicivil Engineering, school of civil engineering, university of Tehran, Tehran, Iran0000-0003-2759-2424Journal Article20190106Nowadays, vibration control in civil engineering is commonly used. Tuned mass damper (TMD) is one of the simplest and most reliable control instruments, which consists of a mass, spring, and damper. TMDs are usually set to the frequency of the first mode of the structure. The sensitivity of the TMD to the changes of structure’s frequency is considered as the weaknesses of this controlling system, and the lack of adjustment of the damper’s parameters to its optimum state or the changes in the structure’s frequency leads to the inefficiency of the system. The non-linear behavior of the structure is an example of changing the natural frequency of the structure during vibration. In this study, to investigate and compare the performance of the single mass damper in the maximum modal displacement (roof) and multiple mass dampers vertically distributed in the height of the structure, based on the modal analysis, two linear and nonlinear models of a 40-story structure were selected. The structure has been modeled in OpenSees software using seven earthquake records. The analysis results for applied earthquakes under the maximum acceleration of 1.0g show that the control of the linear structure by multiple tuned mass dampers (MTMDs) tuned to the first and second modes have more appropriate behavior than others, and the average reduction of the maximum displacement of the roof applying this type of dampers is 14.5%, which is about 2 times more than reduction of the STMD tuned to the first mode and the MTMDs tuned to the first or second modes, systems. However, due to the assumption of tuning the design parameters of the dampers corresponding to their elastic behavior, the performance of single and multiple mass dampers slightly decreases in a nonlinear model of the structure while structural responses are still controlled. Also, for the 10% error caused by misadjusting of the dampers, the behavior of MTMDs is more appropriate.Nowadays, vibration control in civil engineering is commonly used. Tuned mass damper (TMD) is one of the simplest and most reliable control instruments, which consists of a mass, spring, and damper. TMDs are usually set to the frequency of the first mode of the structure. The sensitivity of the TMD to the changes of structure’s frequency is considered as the weaknesses of this controlling system, and the lack of adjustment of the damper’s parameters to its optimum state or the changes in the structure’s frequency leads to the inefficiency of the system. The non-linear behavior of the structure is an example of changing the natural frequency of the structure during vibration. In this study, to investigate and compare the performance of the single mass damper in the maximum modal displacement (roof) and multiple mass dampers vertically distributed in the height of the structure, based on the modal analysis, two linear and nonlinear models of a 40-story structure were selected. The structure has been modeled in OpenSees software using seven earthquake records. The analysis results for applied earthquakes under the maximum acceleration of 1.0g show that the control of the linear structure by multiple tuned mass dampers (MTMDs) tuned to the first and second modes have more appropriate behavior than others, and the average reduction of the maximum displacement of the roof applying this type of dampers is 14.5%, which is about 2 times more than reduction of the STMD tuned to the first mode and the MTMDs tuned to the first or second modes, systems. However, due to the assumption of tuning the design parameters of the dampers corresponding to their elastic behavior, the performance of single and multiple mass dampers slightly decreases in a nonlinear model of the structure while structural responses are still controlled. Also, for the 10% error caused by misadjusting of the dampers, the behavior of MTMDs is more appropriate.Amirkabir University of TechnologyAmirkabir Journal of Civil Engineering2588-297X521020201221Comparison of normal and modified UASB reactors for dairy wastewater treatmentComparison of normal and modified UASB reactors for dairy wastewater treatment25832592354910.22060/ceej.2019.15695.6004FASomayehRahmaniMaster of science student-university of birjandMortezaYeganeh Mirza Aliloouniversity of birjandMohammad RezaDoostiAssociate Professor, Faculty of Engineering, Civil-Environmental Department of university of birjandMohammad JavadZoqicivil environment department of university of birjandJournal Article20190125The present study was conducted to compare the efficiency of normal and modified UASB reactor for the treatment of dairy wastewater. To conduct research, two reactor units with a height of 120 cm and a volume of 48 liters have been used on a laboratory scale and a tank septic tank and an additional sludge blanket have been used to optimize the UASB reactor. Initial inoculation of the reactor was carried out using sewage treatment sludge (active sludge method) slaughterhouse, along with fresh cow discharges and feeding using dry milk. The research lasted for fourteen periods for 154 days, the first period for 30 days including the design and construction of the reactor, the second period for 40 days including starting, forming granules and measuring PH, the third period for 40 days including the continuation of the process The formation of granules and sludge blankets, pH measurements, and preliminary analysis of the removal efficiency of COD and the fourth period for 44 days include the continuation of granulation sludge measurement, PH and the evaluation of COD removal efficiency. The organic loading during four periods was 5.2-11.4 kgCOD/m3.day, and the reactor temperature was in the second to third period in the mesophilic temperature range and during the fourth period at the mesophilic and psychrophilic temperature range. The retention time in the studied period is 24 hours. The output COD yields four to for normal reactor 75-60% and a modified reactor of 94-60%. Optimization of the UASB reactor increases the efficiency by a factor of 22-18% compared to the normal one.The present study was conducted to compare the efficiency of normal and modified UASB reactor for the treatment of dairy wastewater. To conduct research, two reactor units with a height of 120 cm and a volume of 48 liters have been used on a laboratory scale and a tank septic tank and an additional sludge blanket have been used to optimize the UASB reactor. Initial inoculation of the reactor was carried out using sewage treatment sludge (active sludge method) slaughterhouse, along with fresh cow discharges and feeding using dry milk. The research lasted for fourteen periods for 154 days, the first period for 30 days including the design and construction of the reactor, the second period for 40 days including starting, forming granules and measuring PH, the third period for 40 days including the continuation of the process The formation of granules and sludge blankets, pH measurements, and preliminary analysis of the removal efficiency of COD and the fourth period for 44 days include the continuation of granulation sludge measurement, PH and the evaluation of COD removal efficiency. The organic loading during four periods was 5.2-11.4 kgCOD/m3.day, and the reactor temperature was in the second to third period in the mesophilic temperature range and during the fourth period at the mesophilic and psychrophilic temperature range. The retention time in the studied period is 24 hours. The output COD yields four to for normal reactor 75-60% and a modified reactor of 94-60%. Optimization of the UASB reactor increases the efficiency by a factor of 22-18% compared to the normal one.Amirkabir University of TechnologyAmirkabir Journal of Civil Engineering2588-297X521020201221Effects of Dimensions and Amount of Polymer Fibers on the Strength and Durability of Roller-Compacted Concrete under Freeze-Thaw cyclingEffects of Dimensions and Amount of Polymer Fibers on the Strength and Durability of Roller-Compacted Concrete under Freeze-Thaw cycling25932606355910.22060/ceej.2019.15840.6052FAAbouzarShafiepourDepartment of Civil Engineering, Payame Noor University, Tehran, IranShahinShabaniDepartment of Civil Engineering, Payame Noor University, Tehran, IranSeyed FarzinFaeziDepartment of Civil Engineering, Payame Noor University, Tehran, Iran0000-0002-3912-4364Journal Article20190217In recent years, the use of Roller–Compacted Concrete Pavement (RCCP) has developed in road pavement due to its great advantages. Adding fibers to RCC can improve some properties of the concrete, including flexural strength, fatigue resistance, crack growth rate, and shear transfer along cracks and joints. Many experiments have shown the advantages of using fiber-reinforced concrete in RCC, but more information is needed about their behavior in cold regions, and especially the exposure to Freeze-Thaw cycling. Investigation and comparing the effect of polymer fibers on the strength and durability of Roller-Compacted Concrete under Freeze-Thaw cycling are the main goal of the present article. Therefore, specimens with weight percentage of fiber equal to 1, 2.5, and 4% (by weight of cement) and fibers of to 5, 20 and 40 mm lengths are made. Durability test against a Freeze-Thaw cycling and compressive strength are measured on samples after 7, 28 and 90 days. Analysis of the results shows that the additive fiber increases the compressive strength of the RCC, but decreases its durability against the melting and freezing cycles. Therefore, the use of fibers on RCC in cold regions should be done due accuracy and attention.In recent years, the use of Roller–Compacted Concrete Pavement (RCCP) has developed in road pavement due to its great advantages. Adding fibers to RCC can improve some properties of the concrete, including flexural strength, fatigue resistance, crack growth rate, and shear transfer along cracks and joints. Many experiments have shown the advantages of using fiber-reinforced concrete in RCC, but more information is needed about their behavior in cold regions, and especially the exposure to Freeze-Thaw cycling. Investigation and comparing the effect of polymer fibers on the strength and durability of Roller-Compacted Concrete under Freeze-Thaw cycling are the main goal of the present article. Therefore, specimens with weight percentage of fiber equal to 1, 2.5, and 4% (by weight of cement) and fibers of to 5, 20 and 40 mm lengths are made. Durability test against a Freeze-Thaw cycling and compressive strength are measured on samples after 7, 28 and 90 days. Analysis of the results shows that the additive fiber increases the compressive strength of the RCC, but decreases its durability against the melting and freezing cycles. Therefore, the use of fibers on RCC in cold regions should be done due accuracy and attention.Amirkabir University of TechnologyAmirkabir Journal of Civil Engineering2588-297X521020201221Velocity structure in interflow density currentsVelocity structure in interflow density currents26072620357710.22060/ceej.2019.15923.6084FAMohadesehSadeghi AskariDepartment of Hydraulic structures, Shahid Chamran University,MehdiGhomeshidepartment of water structurel engineering, faculty of water scienes engineering, shahid chamran university of ahvaz, ahvaz, iranJournal Article20190309Gravity currents, also known as density currents, or turbidity currents, are happened by the density difference between the flow and its ambient fluid. The density difference can be due to suspended particles, chemicals, soluble materials, and temperature differences. In dams reservoir ambient fluid, usually has a vertical stratification. When the gravity current arrived to ambient fluid, in the position that density of both gravity current and ambient fluid is equal the gravity current abandon the bed and flows in ambient fluid horizontally. Therefore the density current into this reservoir maybe intrude such as interflow density current. This study investigates the inter flow density current in a stratification ambient. For achieve to the objectives of this study, experiments were carried out at a flumes with 9 meters long by 4 discharge 1, 1.5, 2 and 2.5 l/s, and 4 concentration 5, 10, 15 and 20 mg/l, that created density 1003.2, 1006.3, 1009.4 and 1012.5 respectively. Stratification was made by mixture water and salt with vertical gradient. The investigation of velocity profiles showed that the flow is self-similar and velocity fluctuations Continues maximum up to 2.5 times greater than current thickness in the lower layer. The front velocity of currents in stratified environments increases at first then sizeable decreases. It shows that stratified can limited the flow movement. In each three slope, increasing of discharge and concentration increase velocity head of density current in stratified environment. As the slope increases, the current velocity increases at the underflow stage, and in the interflow stage, the slope does not have much effect on the current velocity. Interflow Travel Time decrease in increasing of discharge and concentration. Density current in weaker stratified can travel more distance in the slope and separate latter from the bed.Gravity currents, also known as density currents, or turbidity currents, are happened by the density difference between the flow and its ambient fluid. The density difference can be due to suspended particles, chemicals, soluble materials, and temperature differences. In dams reservoir ambient fluid, usually has a vertical stratification. When the gravity current arrived to ambient fluid, in the position that density of both gravity current and ambient fluid is equal the gravity current abandon the bed and flows in ambient fluid horizontally. Therefore the density current into this reservoir maybe intrude such as interflow density current. This study investigates the inter flow density current in a stratification ambient. For achieve to the objectives of this study, experiments were carried out at a flumes with 9 meters long by 4 discharge 1, 1.5, 2 and 2.5 l/s, and 4 concentration 5, 10, 15 and 20 mg/l, that created density 1003.2, 1006.3, 1009.4 and 1012.5 respectively. Stratification was made by mixture water and salt with vertical gradient. The investigation of velocity profiles showed that the flow is self-similar and velocity fluctuations Continues maximum up to 2.5 times greater than current thickness in the lower layer. The front velocity of currents in stratified environments increases at first then sizeable decreases. It shows that stratified can limited the flow movement. In each three slope, increasing of discharge and concentration increase velocity head of density current in stratified environment. As the slope increases, the current velocity increases at the underflow stage, and in the interflow stage, the slope does not have much effect on the current velocity. Interflow Travel Time decrease in increasing of discharge and concentration. Density current in weaker stratified can travel more distance in the slope and separate latter from the bed.Amirkabir University of TechnologyAmirkabir Journal of Civil Engineering2588-297X521020201221A Traffic Optimization Model Considering Air Pollution Reduction (Case Study: Sadr Overpass)A Traffic Optimization Model Considering Air Pollution Reduction (Case Study: Sadr Overpass)26212634355810.22060/ceej.2019.15958.6094FATorkanAlisoltaniGraduate Student, School of Environment, College of Engineering, University of Tehran, Tehran, IranMajidShafeepour MotlaqAssistant professor, School of Environment, College of Engineering, University of Tehran, Tehran, IranKHosroAshrafiAssociate professor, School of Environment, College of Engineering, University of Tehran, Tehran, IranMeeghatHabibianAssistant Professor, Department of Civil and Environmental Engineering, Amirkabir University of TechnologyJournal Article20190311Achieving the lowest emission rate of urban air pollutants, requires an effective management of mobile air polluting sources. To address this type of management, not only high quality vehicles should be recruited but also the quality of transportation such as amount, slope, and traffic patterns (i.e., steady vs. interrupted flow) should be considered. Therefore, a number of methods are emerged to control the steadiness of traffic flow through traffic network instruments such as traffic lights or ramp metering schemes. In this study, attempts have been made to model a steady traffic flow on the Sadr Overpass to mitigate the least air pollutants production Modeling the optimized traffic volume entering and leaving the ramps whilst maintaining an acceptable service level using a mathematical linear programming technique is presented. Furthermore, a simulation has been conducted using an IVE model to estimate the amount of emissions. The results indicate that temporary closure of ramps in the east-west direction could lead to a steady flowrate on the overpass which decreases the amount of CO and NOx by %54 and %25, respectively. Similarly, in the West-East direction, deploying a cyclic monitoring of traffic flow in the ramp discharging into Modarres Expressway, results in reduction of CO and NOX by %42 and %41, respectively.Achieving the lowest emission rate of urban air pollutants, requires an effective management of mobile air polluting sources. To address this type of management, not only high quality vehicles should be recruited but also the quality of transportation such as amount, slope, and traffic patterns (i.e., steady vs. interrupted flow) should be considered. Therefore, a number of methods are emerged to control the steadiness of traffic flow through traffic network instruments such as traffic lights or ramp metering schemes. In this study, attempts have been made to model a steady traffic flow on the Sadr Overpass to mitigate the least air pollutants production Modeling the optimized traffic volume entering and leaving the ramps whilst maintaining an acceptable service level using a mathematical linear programming technique is presented. Furthermore, a simulation has been conducted using an IVE model to estimate the amount of emissions. The results indicate that temporary closure of ramps in the east-west direction could lead to a steady flowrate on the overpass which decreases the amount of CO and NOx by %54 and %25, respectively. Similarly, in the West-East direction, deploying a cyclic monitoring of traffic flow in the ramp discharging into Modarres Expressway, results in reduction of CO and NOX by %42 and %41, respectively.Amirkabir University of TechnologyAmirkabir Journal of Civil Engineering2588-297X521020201221Using Artificial Neural Network surrogate model to reduce the calculations of leak detection in water distribution networksUsing Artificial Neural Network surrogate model to reduce the calculations of leak detection in water distribution networks26352648371910.22060/ceej.2019.15980.6096FASaeedSarkamaryanDepartment of Civil Engineering, Faculty of Engineering, Shahid Chamran University of Ahvaz, Ahvaz, Iran.Seyed MohammadAshrafiDepartment of Civil Engineering, Faculty of Engineering, Shahid Chamran University of Ahvaz, Ahvaz, Iran.0000-0001-7884-9029AliHaghighiDepartment of Civil Engineering, Faculty of Engineering, Shahid Chamran University of Ahvaz, Ahvaz, Iran.HosseinM.V. SamaniDepartment of Civil Engineering, Faculty of Engineering, Shahid Chamran University of Ahvaz, Ahvaz, Iran.Journal Article20190312The leak detection parameters in the inverse transient analysis (ITA) are obtained in an inverse approach by solving a nonlinear programming problem using metaheuristic algorithms such as genetic algorithms (GA). Beside its high capability in deriving the leak detection parameters, the ITA method is computationally complex and costly. Applying optimization techniques like GA can reduce the complexcity of the ITA method. This study aims to increase the computational efficiency by employing surrogate models in the optimization process of the ITA method. The surrogate model is in fact a simulated sample of the main model capable of approximately calculating the objective function in a fraction of a second. The way these models are integrated into the optimization model highly affects their success or failure. To this end, two algorithms incorporating population-based surrogate models, namely (Pre-selection Strategy) PS and (Best Strategy) BS, were presented. To evaluate and compare the results, a distribution network was used to identify the leak detection parameters. The results indicated an increase in the computational efficiency compared to the ITA method integrated with the GA. The PS algorithm demonstrated the highest performance by reducing the objective function and time complexity by 58% and 78%, respectively.The leak detection parameters in the inverse transient analysis (ITA) are obtained in an inverse approach by solving a nonlinear programming problem using metaheuristic algorithms such as genetic algorithms (GA). Beside its high capability in deriving the leak detection parameters, the ITA method is computationally complex and costly. Applying optimization techniques like GA can reduce the complexcity of the ITA method. This study aims to increase the computational efficiency by employing surrogate models in the optimization process of the ITA method. The surrogate model is in fact a simulated sample of the main model capable of approximately calculating the objective function in a fraction of a second. The way these models are integrated into the optimization model highly affects their success or failure. To this end, two algorithms incorporating population-based surrogate models, namely (Pre-selection Strategy) PS and (Best Strategy) BS, were presented. To evaluate and compare the results, a distribution network was used to identify the leak detection parameters. The results indicated an increase in the computational efficiency compared to the ITA method integrated with the GA. The PS algorithm demonstrated the highest performance by reducing the objective function and time complexity by 58% and 78%, respectively.Amirkabir University of TechnologyAmirkabir Journal of Civil Engineering2588-297X521020201221Monthly precipitation prediction improving using the integrated model based on kernel-wavelet and complementary ensemble empirical mode decompositionMonthly precipitation prediction improving using the integrated model based on kernel-wavelet and complementary ensemble empirical mode decomposition26492660360310.22060/ceej.2019.16043.6109FAKiyoumarsRoushangarCivil Engineering Department, Tabriz University, Tabriz, Iran.RoghayehGhasempourWater resource engineering and management, Faculty of Civil Engineering, University of Tabriz, Tabriz, IranJournal Article20190323Estimates of monthly rainfall are important for various purposes such as flood estimation, drought, irrigation planning, and river basin management. In the present study, the monthly rainfall of Tabriz station was investigated using the intelligent Gaussian Process Regression (GPR) method based on Complementary Ensemble Empirical Mode Decomposition (CEEMD) and Wavelet Transform (WT). Different models were defined based on teleconnection patterns and climatic elements, and the impact of different input parameters was assessed. The obtained results proved high capability and efficiency of the applied method in predicting the monthly precipitation. The results showed that time series decomposition based on wavelet transformation led to more accurate outcomes compared to the complementary ensemble empirical mode decomposition. The best evaluation of test series using wavelet transform decomposition was obtained for the state of modeling based on teleconnection patterns and climatic elements with the values of DC=0.889, R=0.961 and RMSE=0.036. Also, based on the sensitivity analysis, Pt-3 was found to be the most effective parameter in modeling.Estimates of monthly rainfall are important for various purposes such as flood estimation, drought, irrigation planning, and river basin management. In the present study, the monthly rainfall of Tabriz station was investigated using the intelligent Gaussian Process Regression (GPR) method based on Complementary Ensemble Empirical Mode Decomposition (CEEMD) and Wavelet Transform (WT). Different models were defined based on teleconnection patterns and climatic elements, and the impact of different input parameters was assessed. The obtained results proved high capability and efficiency of the applied method in predicting the monthly precipitation. The results showed that time series decomposition based on wavelet transformation led to more accurate outcomes compared to the complementary ensemble empirical mode decomposition. The best evaluation of test series using wavelet transform decomposition was obtained for the state of modeling based on teleconnection patterns and climatic elements with the values of DC=0.889, R=0.961 and RMSE=0.036. Also, based on the sensitivity analysis, Pt-3 was found to be the most effective parameter in modeling.