Amirkabir University of Technology Amirkabir Journal of Civil Engineering 2588-297X 51 5 2019 12 22 Experimental Investigation of the Effect of Collar on Local Scour around Oblong Shaped Bridge Pier Experimental Investigation of the Effect of Collar on Local Scour around Oblong Shaped Bridge Pier 833 842 2884 10.22060/ceej.2018.13888.5518 FA Zahra Taheri Department of water stractures, faculty of water science engineering,shahid chamran university, ahvaz,iran Mehdi Ghomeshi department of water structurel engineering, faculty of water scienes engineering, shahid chamran university of ahvaz, ahvaz, iran Journal Article 2018 01 12 The failure of the bridge caused by local scour, the importance and necessity of studying the prediction of scour depth and ways of reducing it. One of the important method to reduce the effects of erosion factors is to use a thin plate around the bridge pier called collar. Collar dimensions and the position have great effect on reducing local scour around bridge pier. In this research, collar with four forehead length (lca) equal to B, 2B, 4B and 9B (B is width of the pier) are examined. The collars were installed in four levels equal to: on the bed, 0.12B under the bed, 0.5B and B above the bed. The experiments have been conducted with three Froude Numbers equal to 0.13, 0.16 and 0.19 in clear water condition. The experiments have been done on a flume with the length of 6 m, width of 73 cm, and a depth of 60 cm with a slope near zero in Hydraulic Laboratory of Shahid Chamran University of Ahvaz. The results showed that increasing dimensions of collar will increase the efficiency of performance and the best dimension lca (length of oblong collar in the front of the pier) were B and 2B. The best position to install the collar were on the bed and 0.12B under the bed. In these situations the collar had 100% and 88% efficiency in respectively reducing the scour depth. The failure of the bridge caused by local scour, the importance and necessity of studying the prediction of scour depth and ways of reducing it. One of the important method to reduce the effects of erosion factors is to use a thin plate around the bridge pier called collar. Collar dimensions and the position have great effect on reducing local scour around bridge pier. In this research, collar with four forehead length (lca) equal to B, 2B, 4B and 9B (B is width of the pier) are examined. The collars were installed in four levels equal to: on the bed, 0.12B under the bed, 0.5B and B above the bed. The experiments have been conducted with three Froude Numbers equal to 0.13, 0.16 and 0.19 in clear water condition. The experiments have been done on a flume with the length of 6 m, width of 73 cm, and a depth of 60 cm with a slope near zero in Hydraulic Laboratory of Shahid Chamran University of Ahvaz. The results showed that increasing dimensions of collar will increase the efficiency of performance and the best dimension lca (length of oblong collar in the front of the pier) were B and 2B. The best position to install the collar were on the bed and 0.12B under the bed. In these situations the collar had 100% and 88% efficiency in respectively reducing the scour depth. https://ceej.aut.ac.ir/article_2884_780965ae22ea6aee11935f3fb73da841.pdf

Amirkabir University of Technology Amirkabir Journal of Civil Engineering 2588-297X 51 5 2019 12 22 Numerical Investigation of Seepage from Earth Canals and Comparison with Field Measurements Numerical Investigation of Seepage from Earth Canals and Comparison with Field Measurements 843 864 2883 10.22060/ceej.2018.14027.5538 FA Farzin Salmasi 0000-0002-1627-8598 Reza Hosseinzadehasl 1M. Sc. Student in hydraulic structures, Department of Water Engineering, Faculty of Agriculture, University of Tabriz, Tabriz-Iran 0000-0001-6692-5012 Hadi Arvanaghi Associated Professor, Department of Water Engineering, Faculty of Agriculture, University of Tabriz, Tabriz-Iran Journal Article 2018 01 30 The seepage losses from the unlined channels are a major contributor to water losses in the agricultural sector. An understanding of the nature of seepage losses can help to improved water conveyance efficiency and provides solutions for solving water scarcity problems. In this research, numerical simulation was used to study the effective factors on seepage from earth channels. To verify the available information, some of the earthen channels in Zayandehrud irrigation network were used. A number of 246 numerical models including different sections of trapezoidal, rectangular and triangular earthen channels were performed using SEEP/W software. The results showed that, for numerical simulation a width of 15 times the width of the water surface in the channel would be required for the modelling of the left and right lateral boundaries. The comparison of seepage with empirical relationships showed that the empirical relationships reveal a large error in the seepage estimation, although Moritz’s relation with the coefficient of determination 0.373 was better than the rest. Linear and nonlinear multivariate regression relationships provide a suitable match for seepage discharge estimation. Linear relationship was preferable due to small root mean square error (RMSE) and its simplicity. Wetted perimeter has been distinguished effective parameter in seepage from channel, but channel side slope had low effect on seepage. It is suggested that in future studies, the effect of groundwater depth on seepage from the channel should be considered. The seepage losses from the unlined channels are a major contributor to water losses in the agricultural sector. An understanding of the nature of seepage losses can help to improved water conveyance efficiency and provides solutions for solving water scarcity problems. In this research, numerical simulation was used to study the effective factors on seepage from earth channels. To verify the available information, some of the earthen channels in Zayandehrud irrigation network were used. A number of 246 numerical models including different sections of trapezoidal, rectangular and triangular earthen channels were performed using SEEP/W software. The results showed that, for numerical simulation a width of 15 times the width of the water surface in the channel would be required for the modelling of the left and right lateral boundaries. The comparison of seepage with empirical relationships showed that the empirical relationships reveal a large error in the seepage estimation, although Moritz’s relation with the coefficient of determination 0.373 was better than the rest. Linear and nonlinear multivariate regression relationships provide a suitable match for seepage discharge estimation. Linear relationship was preferable due to small root mean square error (RMSE) and its simplicity. Wetted perimeter has been distinguished effective parameter in seepage from channel, but channel side slope had low effect on seepage. It is suggested that in future studies, the effect of groundwater depth on seepage from the channel should be considered. https://ceej.aut.ac.ir/article_2883_c3008b2c6f5370b744850a98a95b73ad.pdf

Amirkabir University of Technology Amirkabir Journal of Civil Engineering 2588-297X 51 5 2019 12 22 Rock-lining interaction calculations for tunnels excavated in Hoek-Brown rock mass considering excavation damaged zone Rock-lining interaction calculations for tunnels excavated in Hoek-Brown rock mass considering excavation damaged zone 865 884 2943 10.22060/ceej.2018.14058.5608 FA Mohammad Reza Zareifard Department of civilengineering, Estahban higher education center Ahmad Fahimifar Department of civil and environment engineering, Amirkabir university of technology 0000-0002-9397-6269 Journal Article 2018 04 03 In this paper, the behavior of tunnels under different damage conditions is examined. In this regard, a fully analytical solution is proposed. The solution is presented for a lined tunnels excavated in elastic–brittle–plastic rock masses with Hoek–Brown failure criterion. The damaged zone is assumed to have cylindrical shape with reduced parameters. On the other hand, the lining is assumed to be homogenous, elastic and cylindrical shaped. The interaction between the lining and the rock masses is also considered. The results obtained by the proposed solution are compared with other analytical and numerical methods. The results indicated that, the effects of the alteration of rock mass properties in the damaged zone may be considerable. In this paper, the behavior of tunnels under different damage conditions is examined. In this regard, a fully analytical solution is proposed. The solution is presented for a lined tunnels excavated in elastic–brittle–plastic rock masses with Hoek–Brown failure criterion. The damaged zone is assumed to have cylindrical shape with reduced parameters. On the other hand, the lining is assumed to be homogenous, elastic and cylindrical shaped. The interaction between the lining and the rock masses is also considered. The results obtained by the proposed solution are compared with other analytical and numerical methods. The results indicated that, the effects of the alteration of rock mass properties in the damaged zone may be considerable. https://ceej.aut.ac.ir/article_2943_6e82873a32b95af115de1c414a1849cb.pdf

Amirkabir University of Technology Amirkabir Journal of Civil Engineering 2588-297X 51 5 2019 12 22 Experimental investigation on exterior RC beam-column connections subjected to cyclic loadings using Steels, Fiber Reinforced Polymers reinforced bars Experimental investigation on exterior RC beam-column connections subjected to cyclic loadings using Steels, Fiber Reinforced Polymers reinforced bars 885 906 2845 10.22060/ceej.2018.14060.5547 FA Hossein Rezaee Azariani phd student,civil engineering- ferdowsi university of mashhad Hashem Shariatmadar civil - engineering- ferdowsi university of mashhad Mohammad Reza Esfahani Ferdowsi University of Mashhad Journal Article 2018 02 07 In the present experimental research, the behavior of exterior reinforced concrete (RC) beam-column connections subjected to cyclic loading is studied using steel and Glass Fiber-Reinforced Polymer (GFRP) reinforcing bars. In this research, 8 specimens of exterior RC beam-column connections were tested in which four specimens included GFRP reinforcing bars and the remaining four specimens included steel bars. The confinement of beam longitudinal bars was different in the connections. Also, two types of concretes were used with the strengths 30 and 45 MPa, respectively. The specimens were tested under cyclic loading. The results showed that GFRP has great ability in dissipation of energy, yet the amount of the dissipated energy by GFRP is less than that of steel bars. Although the amount of energy absorbed by GFRP materials was lower than steel bars, they could be used instead of steel bars or in combination with steel bars due to the resistance to the corrosion. Load-story drift envelop for GFRP strengthened specimens with high strength concrete has the essential requirements for acting as a member of a moment frame in seismic regions, while all the specimens with steel bars have these requirements. In case of GFRP strengthened specimens with high and normal strength concrete, increasing the cyclic loading results in flexural failure of the beam in the beam-column connection region. Increasing the confinement of concrete beams leads to the reduction of crack width. Furthermore, at higher drifts, spalling was not observed in concrete surface in beam-column connection region. In the present experimental research, the behavior of exterior reinforced concrete (RC) beam-column connections subjected to cyclic loading is studied using steel and Glass Fiber-Reinforced Polymer (GFRP) reinforcing bars. In this research, 8 specimens of exterior RC beam-column connections were tested in which four specimens included GFRP reinforcing bars and the remaining four specimens included steel bars. The confinement of beam longitudinal bars was different in the connections. Also, two types of concretes were used with the strengths 30 and 45 MPa, respectively. The specimens were tested under cyclic loading. The results showed that GFRP has great ability in dissipation of energy, yet the amount of the dissipated energy by GFRP is less than that of steel bars. Although the amount of energy absorbed by GFRP materials was lower than steel bars, they could be used instead of steel bars or in combination with steel bars due to the resistance to the corrosion. Load-story drift envelop for GFRP strengthened specimens with high strength concrete has the essential requirements for acting as a member of a moment frame in seismic regions, while all the specimens with steel bars have these requirements. In case of GFRP strengthened specimens with high and normal strength concrete, increasing the cyclic loading results in flexural failure of the beam in the beam-column connection region. Increasing the confinement of concrete beams leads to the reduction of crack width. Furthermore, at higher drifts, spalling was not observed in concrete surface in beam-column connection region. https://ceej.aut.ac.ir/article_2845_4b29fa4efe4fb7bc667c7b301b74d52d.pdf

Amirkabir University of Technology Amirkabir Journal of Civil Engineering 2588-297X 51 5 2019 12 22 Sensitivity Analysis of Hydraulic Parameters on Contaminant Intrusion in Transient Conditions Sensitivity Analysis of Hydraulic Parameters on Contaminant Intrusion in Transient Conditions 907 924 2934 10.22060/ceej.2018.14230.5595 FA Milad Payesteh Msc graduated in Civil Engineering, Jundi-Shapur University of Technology, Dezful, Iran Alireza Keramat Faculty of Civil Engineering, Jondi Shapur University of Technology, Dezful, Iran 0000-0002-6280-4931 Journal Article 2018 03 18 Water quality degrades due to the complex physical, chemical and biological processes passing through the transmission lines. One of these widely attracted processes is contaminant intrusion due to a transient event. When the negative pressure wave of water hammer reaches a structural deteriorations such as a leakage, it can suddenly sucks pollution from the surrounding area of leakage to the main pipe flow which can in turn endanger public health. The purpose of this study is to determine the effect of hydraulic parameters on the duration of negative pressure and the magnitude of the negative pressure and subsequently the volume of contaminant intrusion, in the case of a simple reservoir-pipe[1]valve system with a leakage. In this study, the Eulerian approach using method of characteristics was used to model the transient flow. The total volume of contaminant parcel (VCPt) passing through the leakage to the main pipe flow is obtained from the Lagrangian solution of the advection equation. The results indicate that the volume of intrusion is dominated by the magnitude and duration of negative pressure at the leak. The intruded parcel is considered as a decisive criterion to compare various transient scenarios. Reservoir pressure head, fluid velocity inside the pipe, wave speed, pipe diameter, leak diameter and leakage location are respectively the most effective pipe and flow parameters on contaminant intrusion which their specific significance is investigated in this research. Investigation of the interaction of these factors in the volume of contaminant intrusion can be considered as a subject for future research. Water quality degrades due to the complex physical, chemical and biological processes passing through the transmission lines. One of these widely attracted processes is contaminant intrusion due to a transient event. When the negative pressure wave of water hammer reaches a structural deteriorations such as a leakage, it can suddenly sucks pollution from the surrounding area of leakage to the main pipe flow which can in turn endanger public health. The purpose of this study is to determine the effect of hydraulic parameters on the duration of negative pressure and the magnitude of the negative pressure and subsequently the volume of contaminant intrusion, in the case of a simple reservoir-pipe[1]valve system with a leakage. In this study, the Eulerian approach using method of characteristics was used to model the transient flow. The total volume of contaminant parcel (VCPt) passing through the leakage to the main pipe flow is obtained from the Lagrangian solution of the advection equation. The results indicate that the volume of intrusion is dominated by the magnitude and duration of negative pressure at the leak. The intruded parcel is considered as a decisive criterion to compare various transient scenarios. Reservoir pressure head, fluid velocity inside the pipe, wave speed, pipe diameter, leak diameter and leakage location are respectively the most effective pipe and flow parameters on contaminant intrusion which their specific significance is investigated in this research. Investigation of the interaction of these factors in the volume of contaminant intrusion can be considered as a subject for future research. https://ceej.aut.ac.ir/article_2934_5dc126b503e374b0e08231344a7f493f.pdf

Amirkabir University of Technology Amirkabir Journal of Civil Engineering 2588-297X 51 5 2019 12 22 Laboratory Investigation of the Effect of Deep Soil Mixing Method on Engineering Properties of Soft Clay Stabilized by Slag and Lime Laboratory Investigation of the Effect of Deep Soil Mixing Method on Engineering Properties of Soft Clay Stabilized by Slag and Lime 925 942 2981 10.22060/ceej.2018.14279.5609 FA Parham Rabbani Department of Civil Engineering, Islamic Azad University, ARAK Branch, ARAK, IRAN Seyed Hamid LAJEVARDI Journal Article 2018 04 04 Soft clayey soil generally has high compressibility and low strength. Presence of this soil type in the site of civil projects can always be a challenge. Soil stabilization is one of the useful ways to improve problematic soils. Cutter Soil Mixing (CSM) is almost a new method for deep stabilization. This laboratory study, investigate the effect of various depths of stabilization on the engineering properties of soft clay treated by CSM method. To prepare samples, simulate different depths and related overburden pressures new devices were designed, modified and made. Moreover, mixture of blast furnace slag and hydrated lime slurry was used in this method for the first time. Prepared samples were cured for 28, 56 days under saturated conditions, and various overburden pressures to investigate the effect of this stabilization method on physical and mechanical properties of them. The obtained results revealed that increasing the depth of stabilization decreases the moisture content of the samples, increases their saturated/dry densities and improves the strength parameters of them. Moreover, mechanical properties of the samples showed fewer changes by passing the specific depth. Soft clayey soil generally has high compressibility and low strength. Presence of this soil type in the site of civil projects can always be a challenge. Soil stabilization is one of the useful ways to improve problematic soils. Cutter Soil Mixing (CSM) is almost a new method for deep stabilization. This laboratory study, investigate the effect of various depths of stabilization on the engineering properties of soft clay treated by CSM method. To prepare samples, simulate different depths and related overburden pressures new devices were designed, modified and made. Moreover, mixture of blast furnace slag and hydrated lime slurry was used in this method for the first time. Prepared samples were cured for 28, 56 days under saturated conditions, and various overburden pressures to investigate the effect of this stabilization method on physical and mechanical properties of them. The obtained results revealed that increasing the depth of stabilization decreases the moisture content of the samples, increases their saturated/dry densities and improves the strength parameters of them. Moreover, mechanical properties of the samples showed fewer changes by passing the specific depth. https://ceej.aut.ac.ir/article_2981_9ff0525c64bf3d4c9957a1d4397f1b40.pdf

Amirkabir University of Technology Amirkabir Journal of Civil Engineering 2588-297X 51 5 2019 12 22 Parametric Study of Welded Gusset Plates Performance in Concentric Braced Steel Frames under Cyclic Loading Parametric Study of Welded Gusset Plates Performance in Concentric Braced Steel Frames under Cyclic Loading 943 962 2919 10.22060/ceej.2018.14163.5575 FA Mehrdad Hejazi University of Isfahan Shahram Salehi University of Isfahan Mohammad Reza Zare University of Isfahan Journal Article 2018 03 04 In this paper, the behavior of gusset plates in concentric braced steel frames under cyclic loading has been studied. The behavior is studied by comparing dissipated energy, plastic strains of welds between the gusset plate and beam, column and bracing, plastic strains at the midspan of the bracing, and Von Mises stresses and plastic strains of the gusset plates. Studied parameters are the thickness and shape of the gusset plate, use of linear and elliptical clearance, non-existence of clearance, edge, longitudinal and internal stiffeners, and use of a single- or double-profile bracing. Non-linear analysis has been performed by the finite element ABAQUS code. Obtained results showed that by eliminating the clearance, the plastic strains in weld between the gusset plate and bracing and plastic strains in the gusset plate are increased considerably. The maximum value of energy dissipation has belonged to edge stiffeners with an increase of 15.4% compared to the unstiffened gusset plate. In this paper, the behavior of gusset plates in concentric braced steel frames under cyclic loading has been studied. The behavior is studied by comparing dissipated energy, plastic strains of welds between the gusset plate and beam, column and bracing, plastic strains at the midspan of the bracing, and Von Mises stresses and plastic strains of the gusset plates. Studied parameters are the thickness and shape of the gusset plate, use of linear and elliptical clearance, non-existence of clearance, edge, longitudinal and internal stiffeners, and use of a single- or double-profile bracing. Non-linear analysis has been performed by the finite element ABAQUS code. Obtained results showed that by eliminating the clearance, the plastic strains in weld between the gusset plate and bracing and plastic strains in the gusset plate are increased considerably. The maximum value of energy dissipation has belonged to edge stiffeners with an increase of 15.4% compared to the unstiffened gusset plate. https://ceej.aut.ac.ir/article_2919_6271faadeedd7626d661856b7a004e27.pdf

Amirkabir University of Technology Amirkabir Journal of Civil Engineering 2588-297X 51 5 2019 12 22 Investigating the characteristics of surface oscillations of flow through obstacles using Roshko and Ursell dimensionless numbers Investigating the characteristics of surface oscillations of flow through obstacles using Roshko and Ursell dimensionless numbers 963 978 2936 10.22060/ceej.2018.14234.5598 FA Ehsan Moghaddasi Master's graduates of Civil_River Engineering, Shahid Chamran university of Ahvaz, Iran Nazanin Shahkarami Assistant Professor, Faculty of Engineering, Arak University, Arak, Iran Journal Article 2018 03 18 Vortex is shed by flow collision with obstacles in its path. If the frequency of vortex shedding equals the frequency of natural oscillations of flow, resonance will be created and transverse oscillation perpendicular to flow with greatest wave amplitude will occur. In this study, in order to investigate the characteristics of the transverse wave caused by the vortex shedding of the obstacles, 135 cylinder barriers with a diameter of 20 mm in 5 different configurations were arranged in the laboratory flume. In total, 900 tests were carried out which variables were flow discharge, average flow depth, channel slope, longitudinal and transverse distance between obstacles. In each test, after the formation of transverse oscillations, their characteristics including amplitude and frequency of wave were recorded. Then, the effective variables on transverse wave characteristics and their effects on the involved dimensionless numbers were investigated. The results indicated whatever the flow discharge is increased, the maximum wave amplitude due to resonance occurs in larger average flow depth, which has more amount. Also by changing the longitudinal distance of obstacles, Roshko’s changes relative to increasing of Ursell were ascending at the beginning and they were reversed after reaching a certain range of Ursell number; moreover, by increasing the flow discharge, the rate of Ursell changes relative to Roshko decreased. Finally, by using dimensional analysis and statistical software, the equations between Roshko with Ursell and Froude numbers were proposed for each of the modes I and II and the validation of equations were approved (R2= 0.92). Vortex is shed by flow collision with obstacles in its path. If the frequency of vortex shedding equals the frequency of natural oscillations of flow, resonance will be created and transverse oscillation perpendicular to flow with greatest wave amplitude will occur. In this study, in order to investigate the characteristics of the transverse wave caused by the vortex shedding of the obstacles, 135 cylinder barriers with a diameter of 20 mm in 5 different configurations were arranged in the laboratory flume. In total, 900 tests were carried out which variables were flow discharge, average flow depth, channel slope, longitudinal and transverse distance between obstacles. In each test, after the formation of transverse oscillations, their characteristics including amplitude and frequency of wave were recorded. Then, the effective variables on transverse wave characteristics and their effects on the involved dimensionless numbers were investigated. The results indicated whatever the flow discharge is increased, the maximum wave amplitude due to resonance occurs in larger average flow depth, which has more amount. Also by changing the longitudinal distance of obstacles, Roshko’s changes relative to increasing of Ursell were ascending at the beginning and they were reversed after reaching a certain range of Ursell number; moreover, by increasing the flow discharge, the rate of Ursell changes relative to Roshko decreased. Finally, by using dimensional analysis and statistical software, the equations between Roshko with Ursell and Froude numbers were proposed for each of the modes I and II and the validation of equations were approved (R2= 0.92). https://ceej.aut.ac.ir/article_2936_ec7f346604f518906d35ef0492709f78.pdf

Amirkabir University of Technology Amirkabir Journal of Civil Engineering 2588-297X 51 5 2019 12 22 Performance evaluation of WRF/CALMET integrated model in expanding inflow wind field to air quality models Performance evaluation of WRF/CALMET integrated model in expanding inflow wind field to air quality models 979 992 2975 10.22060/ceej.2018.14278.5610 FA Mohsen Rahimian Faculty of Water and Environment, Shahid Beheshti University, Tehran, Iran 0000-0003-2505-0226 Yousef Rashidi Department of Environmental Technologies, Environmental Sciences Research Institute, Shahid Beheshti University, Tehran, Iran 0000-0002-6404-4067 Journal Article 2018 04 05 The necessity of having comprehensive information on wind field in a particular area is important for various reasons. How air pollutants are scattered and released is one of the most important ones. In this study we explore the efficiency and usefulness of integrating WRF mesoscale numerical model with CALMET meteorological calculation model in order to generate high accurate wind field in a region centered in Tehran in a five days period from 5th to 10th July 2014. On the first stage three dimensional wind fields of the region were processed using WRF model and the result made available to CALMET model as an initial guess. On the second stage the WRF model was put aside and surface meteorological data along with the atmosphere above the Mehrabad metrological station were processed using SMERGE and READ62 model respectively; the results used directly in CALMET model. Finally, the CALMET model was implemented using the combination of WRF model data and observational data. Then the efficiency of mentioned methods was explored using statistical analysis, comparing temperature profiles, wind speed and simulated data with observational data of Imam Khomeni airport metrological station in the intended period. Results of the statistical indexes which were used in this study including index of agreement (IOA), mean bias error (MBE), root mean-square error (RMSE) and mean absolute error (MAE) indicate the high power of WRF/CALMET integrated model in simulating wind field of the region so that the value of index of agreement for wind speed in the first stage is 0.70- 0.85, in the second stage is 0.59-0.83 and in the third stage is 0.76-0.90. Generally the results of this study shows that using and combining the outputs of WRF model with observational data as input for CALMET model is an efficient way for generating accurate metrological data for studying air quality modeling specially in countries like Iran in which the upper atmosphere data is hardly measured. The necessity of having comprehensive information on wind field in a particular area is important for various reasons. How air pollutants are scattered and released is one of the most important ones. In this study we explore the efficiency and usefulness of integrating WRF mesoscale numerical model with CALMET meteorological calculation model in order to generate high accurate wind field in a region centered in Tehran in a five days period from 5th to 10th July 2014. On the first stage three dimensional wind fields of the region were processed using WRF model and the result made available to CALMET model as an initial guess. On the second stage the WRF model was put aside and surface meteorological data along with the atmosphere above the Mehrabad metrological station were processed using SMERGE and READ62 model respectively; the results used directly in CALMET model. Finally, the CALMET model was implemented using the combination of WRF model data and observational data. Then the efficiency of mentioned methods was explored using statistical analysis, comparing temperature profiles, wind speed and simulated data with observational data of Imam Khomeni airport metrological station in the intended period. Results of the statistical indexes which were used in this study including index of agreement (IOA), mean bias error (MBE), root mean-square error (RMSE) and mean absolute error (MAE) indicate the high power of WRF/CALMET integrated model in simulating wind field of the region so that the value of index of agreement for wind speed in the first stage is 0.70- 0.85, in the second stage is 0.59-0.83 and in the third stage is 0.76-0.90. Generally the results of this study shows that using and combining the outputs of WRF model with observational data as input for CALMET model is an efficient way for generating accurate metrological data for studying air quality modeling specially in countries like Iran in which the upper atmosphere data is hardly measured. https://ceej.aut.ac.ir/article_2975_2ef3e50fd7c1091dda165f25be7f64fd.pdf

Amirkabir University of Technology Amirkabir Journal of Civil Engineering 2588-297X 51 5 2019 12 22 The effect of Stiffness on Behavior of Isolated Tall Buildings The effect of Stiffness on Behavior of Isolated Tall Buildings 993 1016 2937 10.22060/ceej.2018.14184.5579 FA Hamidreza Sharifi MSc Graduated, Civil Department/Khomeinishahr barch of Azad Islamic University Sayed Behzad Talaeitabab Assistant professor, Civil Department/Khomeinishahr barch of Azad Islamic University Journal Article 2018 03 09 The basis of seismic isolation in reducing the acceleration applied to structures is based on an increase in the natural period. In high-rise structures, the natural period itself is high. In this case the flexibility of superstructure may be in conflict with its elastic behavior. In the present study, 240 structures were modeled and analyzed in the first step to the question of whether the addition or reduction of the stiffness of the substructure and superstructure (1-100 times and 0.001 to 1 times respectively) affected the floors acceleration distribution or not? The results of the analysis of structures that were of five types of plans and at elevations 10, 15, 20, 24 and 28 floors showed that adding the stiffness of the superstructure can lead to a decrease of about 30 and 55 percent of the maximum roof acceleration and average acceleration of floors respectively (relative to the isolated structure without increasing the stiffness of the superstructure); However, the use of base isolation in the structures decreased about 50% of roof acceleration. The significant decrease in roof acceleration was related to structures with a 10 times increase in the stiffness of the superstructure compared to normal structure. In the next step, with the push-over analysis of 15 structures of this set, it was determined that in all isolated structures (with varying stiffness), the superstructure will remain in elastic state. The number of plastic hinges in the elastic region (before IO performance level) increased by 50% in isolated structures compare to fixed base and none of the plastic hinges formed in the members, exceeded from IO region. The basis of seismic isolation in reducing the acceleration applied to structures is based on an increase in the natural period. In high-rise structures, the natural period itself is high. In this case the flexibility of superstructure may be in conflict with its elastic behavior. In the present study, 240 structures were modeled and analyzed in the first step to the question of whether the addition or reduction of the stiffness of the substructure and superstructure (1-100 times and 0.001 to 1 times respectively) affected the floors acceleration distribution or not? The results of the analysis of structures that were of five types of plans and at elevations 10, 15, 20, 24 and 28 floors showed that adding the stiffness of the superstructure can lead to a decrease of about 30 and 55 percent of the maximum roof acceleration and average acceleration of floors respectively (relative to the isolated structure without increasing the stiffness of the superstructure); However, the use of base isolation in the structures decreased about 50% of roof acceleration. The significant decrease in roof acceleration was related to structures with a 10 times increase in the stiffness of the superstructure compared to normal structure. In the next step, with the push-over analysis of 15 structures of this set, it was determined that in all isolated structures (with varying stiffness), the superstructure will remain in elastic state. The number of plastic hinges in the elastic region (before IO performance level) increased by 50% in isolated structures compare to fixed base and none of the plastic hinges formed in the members, exceeded from IO region. https://ceej.aut.ac.ir/article_2937_8fc687aa152e8199fe9e73304d407bca.pdf

Amirkabir University of Technology Amirkabir Journal of Civil Engineering 2588-297X 51 5 2019 12 22 Interdependence of Hydraulic Parameters in Transient Induced Contaminant Intrusion in a Pipeline Interdependence of Hydraulic Parameters in Transient Induced Contaminant Intrusion in a Pipeline 1017 1032 3036 10.22060/ceej.2018.14486.5670 FA Milad Payesteh Msc graduated in Civil Engineering, Jundi-Shapur University of Technology, Dezful, Iran Alireza Keramat Faculty of Civil Engineering, Jondi Shapur University of Technology, Dezful, Iran 0000-0002-6280-4931 Journal Article 2018 05 23 Contaminant intrusion during transients in pipelines is a remarkable mechanism which usually leads to declining the quality of the contained water. When rarefaction waves of water hammer reach a leakage, the negative pressure can suddenly suck pollution from surrounding area of leakage to the main pipe flow, thus deteriorating water quality. In this research, numerical and mathematical modeling of a reservoir-pipe-valve system with a leakage has been used to study the effect of hydraulic situations on the volume of contamination intruded into the pipeline during a waterhammer. Eulerian method of characteristics was employed to model the transient flow. The total Volume of Contaminant Parcel (VCPt) penetrating through the leakage is evaluated by Lagrangian solution of the advection equation and then it is established the criteria to compare various transient scenarios and the interconnection between key parameters. In order to elucidate this phenomenon in real pipe systems, the amount of contaminant intrusion is estimated for 72 different cases. They include two lengths of pipeline (say short and long), three different leakage locations, three different fluid velocities, two leak diameters and two pipeline materials (elastic and viscoelastic). The results indicate that the amount of intrusion in viscoelastic pipes is clearly less than that in elastic pipes especially in long pipelines: the ratio of intrusion in viscoelastic to elastic pipes on average is 0.027 and 0.496 in 2300m and 540m pipe, respectively. The critical zone of high intrusion risk is placed close to the downstream valve for small leak sizes, nevertheless, it is hard to estimate this zone in case of big leaks due to significant valve-leak-reservoir induced reflection waves. Contaminant intrusion during transients in pipelines is a remarkable mechanism which usually leads to declining the quality of the contained water. When rarefaction waves of water hammer reach a leakage, the negative pressure can suddenly suck pollution from surrounding area of leakage to the main pipe flow, thus deteriorating water quality. In this research, numerical and mathematical modeling of a reservoir-pipe-valve system with a leakage has been used to study the effect of hydraulic situations on the volume of contamination intruded into the pipeline during a waterhammer. Eulerian method of characteristics was employed to model the transient flow. The total Volume of Contaminant Parcel (VCPt) penetrating through the leakage is evaluated by Lagrangian solution of the advection equation and then it is established the criteria to compare various transient scenarios and the interconnection between key parameters. In order to elucidate this phenomenon in real pipe systems, the amount of contaminant intrusion is estimated for 72 different cases. They include two lengths of pipeline (say short and long), three different leakage locations, three different fluid velocities, two leak diameters and two pipeline materials (elastic and viscoelastic). The results indicate that the amount of intrusion in viscoelastic pipes is clearly less than that in elastic pipes especially in long pipelines: the ratio of intrusion in viscoelastic to elastic pipes on average is 0.027 and 0.496 in 2300m and 540m pipe, respectively. The critical zone of high intrusion risk is placed close to the downstream valve for small leak sizes, nevertheless, it is hard to estimate this zone in case of big leaks due to significant valve-leak-reservoir induced reflection waves. https://ceej.aut.ac.ir/article_3036_4b86ca48d90bd5f0978afa3a012503a4.pdf

Amirkabir University of Technology Amirkabir Journal of Civil Engineering 2588-297X 51 5 2019 12 22 Investigation on the Effect of Titanium Oxy di-fluoride (TiOF2) Nanoparticles on the Rutting Behavior of Asphalt Mixtures Investigation on the Effect of Titanium Oxy di-fluoride (TiOF2) Nanoparticles on the Rutting Behavior of Asphalt Mixtures 1033 1046 2959 10.22060/ceej.2018.14231.5597 FA MAHYAR Arabani faculty member 0000-0002-4802-3725 Ali Sahraei faculty of engineering, university of guilan Leila Mivehi faculty of engineering, university of guilan Journal Article 2018 03 18 Rutting is one of the main reasons for reducing the life of the asphalt pavements. Asphalt binder modification using various additives is one of the most common methods for rutting reduction and asphalt modification. Many materials such as oils, ashes, polymers, and nanomaterials are used in asphalt binder to improve asphalt mixtures. In this paper, physical and rheological properties of asphalt mixture modified by titanium oxy di-fluoride (TiOF2) nanoparticles as an additive were investigated. The degree of penetration and the softening point tests on the control and modified asphalt binder showed increasing nanoparticles amount caused an increment in the softening point and decrement the degree of penetration due to friction increasing between needles and bitumen. Rheological properties were investigated by Dynamic Shear Rheometer (DSR) test on the control, modified asphalt binders and the asphalt binders obtained from the rolling thin film oven test. Repeated Load Axial (RLA) Test were performed to study the rutting properties of asphalt mixtures. The results showed that the addition of titanium oxy di-fluoride nanoparticles (gray titanium nanoparticles) to the asphalt binder increased the resistance of shear deformation and improved the elastic behavior. Rutting is one of the main reasons for reducing the life of the asphalt pavements. Asphalt binder modification using various additives is one of the most common methods for rutting reduction and asphalt modification. Many materials such as oils, ashes, polymers, and nanomaterials are used in asphalt binder to improve asphalt mixtures. In this paper, physical and rheological properties of asphalt mixture modified by titanium oxy di-fluoride (TiOF2) nanoparticles as an additive were investigated. The degree of penetration and the softening point tests on the control and modified asphalt binder showed increasing nanoparticles amount caused an increment in the softening point and decrement the degree of penetration due to friction increasing between needles and bitumen. Rheological properties were investigated by Dynamic Shear Rheometer (DSR) test on the control, modified asphalt binders and the asphalt binders obtained from the rolling thin film oven test. Repeated Load Axial (RLA) Test were performed to study the rutting properties of asphalt mixtures. The results showed that the addition of titanium oxy di-fluoride nanoparticles (gray titanium nanoparticles) to the asphalt binder increased the resistance of shear deformation and improved the elastic behavior. https://ceej.aut.ac.ir/article_2959_779efbd24d5a7e37ce8dc93e7c04d572.pdf

Amirkabir University of Technology Amirkabir Journal of Civil Engineering 2588-297X 51 5 2019 12 22 Semi-active fuzzy control of SDOF systems under loading of rotary machines by tuned mass dampers Semi-active fuzzy control of SDOF systems under loading of rotary machines by tuned mass dampers 1047 1062 3023 10.22060/ceej.2018.14219.5590 FA Meysam Ramezani international institute of earthquake engineering and seismology Akbar Bathaei Earthquake Engineering Department, University of Tehran, Tehran, Iran S. Mehdi Zahrai School Civil Engineering, University of Tehran, Tehran, Iran 0000-0003-2759-2424 Journal Article 2018 03 16 Dynamic vibrations of mechanical equipment might undesirably affect their performance and the structures on which they are installed. The gradual increase in angular velocity of such equipment and getting close to natural frequency of the structure leads to some phenomena such as resonance, pseudo resonance, beating and pseudo beating phenomenon. Therefore, dynamic responses of these structures should be reduced. Tuned mass dampers (TMDs) as one of the most reliable and simplest instruments to achieve this goal have been attracted by experts. The inertia force makes this kind of dampers vibrate in opposite direction and cause reduction in response of structure. Within seconds, by dedicating various parameters for TMD, their great performance can be augmented. There are lots of different strategies to assign these variable parameters. In this study, semi-active control approaches have been used to decrease the response of a single degree of freedom structure subjected to the above[1]mentioned probabilistic phenomena. In addition, some existing optimum functions have been applied to determine the TMD’s frequency and damping parameters. These parameters of semi-active TMD are predicted utilizing two different strategies: the fuzzy logic system and ground-hook algorithm. The logic of making alteration to damping ratio is based on regaining the equilibrium of structure as it vibrates. Copping with different phenomena, results of this investigation indicate the advantages of using semi-active tuned mass damper to dramatically decrease the system displacement by 32 to 47 percent. Moreover, using fuzzy logic systems to set damping parameters of TMD, results in 1.5 to 6.2 percent displacement reduction in comparison with Ground-Hook algorithm. The conducted analysis for a wide range of optimal frequencies illustrate that fuzzy logic system is less sensitive to mistuning of TMD’s optimal frequency Dynamic vibrations of mechanical equipment might undesirably affect their performance and the structures on which they are installed. The gradual increase in angular velocity of such equipment and getting close to natural frequency of the structure leads to some phenomena such as resonance, pseudo resonance, beating and pseudo beating phenomenon. Therefore, dynamic responses of these structures should be reduced. Tuned mass dampers (TMDs) as one of the most reliable and simplest instruments to achieve this goal have been attracted by experts. The inertia force makes this kind of dampers vibrate in opposite direction and cause reduction in response of structure. Within seconds, by dedicating various parameters for TMD, their great performance can be augmented. There are lots of different strategies to assign these variable parameters. In this study, semi-active control approaches have been used to decrease the response of a single degree of freedom structure subjected to the above[1]mentioned probabilistic phenomena. In addition, some existing optimum functions have been applied to determine the TMD’s frequency and damping parameters. These parameters of semi-active TMD are predicted utilizing two different strategies: the fuzzy logic system and ground-hook algorithm. The logic of making alteration to damping ratio is based on regaining the equilibrium of structure as it vibrates. Copping with different phenomena, results of this investigation indicate the advantages of using semi-active tuned mass damper to dramatically decrease the system displacement by 32 to 47 percent. Moreover, using fuzzy logic systems to set damping parameters of TMD, results in 1.5 to 6.2 percent displacement reduction in comparison with Ground-Hook algorithm. The conducted analysis for a wide range of optimal frequencies illustrate that fuzzy logic system is less sensitive to mistuning of TMD’s optimal frequency https://ceej.aut.ac.ir/article_3023_09d37c08f7b129e96277388757530c72.pdf

Amirkabir University of Technology Amirkabir Journal of Civil Engineering 2588-297X 51 5 2019 12 22 Experimental Study of Hydraulic Performance of Stepped Spillway with a Curve Axis Affected by Downstream Channel Width Changes Experimental Study of Hydraulic Performance of Stepped Spillway with a Curve Axis Affected by Downstream Channel Width Changes 1063 1076 2942 10.22060/ceej.2018.14250.5602 FA Ali Forudi Khowr Department of Civil Engineering, University of Tabriz, Tabriz, Iran. Kiyoumars Roushangar Civil Engineering Department, Tabriz University, Tabriz, Iran. Mojtaba Saneie Hydraulic Structures, Soil Conservation and Watershed Management Research Institute (SCWMRI), Tehran, Iran. Journal Article 2018 03 26 Realization of the advantages of a higher degree of energy dissipation have created an increasing interest in stepped spillways. This study using a three dimensional, 1:50 scale, physical model was conducted to investigate the impact of variation downstream channel width of the converging stepped spillways with a curve axis. For this purpose, the converging stepped spillway with a curve axis was constructed and tested in four ratio of downstream channel width to spillway width ( ) ranging from 0.214 to 0.286. The results of the experiments indicated that in the converging steeped spillway by increasing total upstream head, the discharge coefficient will go up for each of the width ratio ( ) and before submergence stage for the spillway, the discharge coefficient is independent of downstream channel width variations. By contrast, when the spillway was submerged, there is a decrease in the coefficient of discharge can be caused by tailwater submergence and it causes the differences in the discharge coefficient for each of the widths ratio ( ). Also, the obtained data demonstrates that as increases, the flow depth and static pressure decreases at the bottom and the toe of the spillway model. Moreover, it was observed that as discharge increases, the energy dissipation decreases for all models, but model with higher ratio of lead to reduce more energy dissipation in higher discharge. In addition model with width ratio of due Realization of the advantages of a higher degree of energy dissipation have created an increasing interest in stepped spillways. This study using a three dimensional, 1:50 scale, physical model was conducted to investigate the impact of variation downstream channel width of the converging stepped spillways with a curve axis. For this purpose, the converging stepped spillway with a curve axis was constructed and tested in four ratio of downstream channel width to spillway width ( ) ranging from 0.214 to 0.286. The results of the experiments indicated that in the converging steeped spillway by increasing total upstream head, the discharge coefficient will go up for each of the width ratio ( ) and before submergence stage for the spillway, the discharge coefficient is independent of downstream channel width variations. By contrast, when the spillway was submerged, there is a decrease in the coefficient of discharge can be caused by tailwater submergence and it causes the differences in the discharge coefficient for each of the widths ratio ( ). Also, the obtained data demonstrates that as increases, the flow depth and static pressure decreases at the bottom and the toe of the spillway model. Moreover, it was observed that as discharge increases, the energy dissipation decreases for all models, but model with higher ratio of lead to reduce more energy dissipation in higher discharge. In addition model with width ratio of due https://ceej.aut.ac.ir/article_2942_2a0f97f81755e2878b264adf39cba68e.pdf

Amirkabir University of Technology Amirkabir Journal of Civil Engineering 2588-297X 51 5 2019 12 22 Seismic Performance of Reinforced Concrete Shear Walls with Eccentric Openings Seismic Performance of Reinforced Concrete Shear Walls with Eccentric Openings 1077 1096 2912 10.22060/ceej.2018.13994.5549 FA Ali Kheyroddin استاد دانشگاه سمنان 0000-0001-7802-2013 Seyyed Armin Hosseini Department of Civil Engineering, Semnan University Semnan, Iran Journal Article 2018 02 11 The strong earthquakes recorded worldwide have shown that the damages and the failure mechanisms of the reinforced concrete structural walls depend on a series of factors, such as the shape in plan and elevation, the dimensions of the walls and openings. During the past several decades, extensive experimental and analytical studies have been conducted on the behavior of structural walls with openings. This paper describes an analytical study carried out on of reinforced concrete walls with eccentric opening. In order to achieve this goal, variations in various parameters including changes in the aspect ratio of the openings, the stiffness of the link beam, the aspect ratio of the openings with simple connection at the both end of link beams and the aspect ratio of the walls are studied. Story drift, center of mass displacement, shear and moment in coupling beams and axial load in columns which coupled with shear wall are analyzed and compared together. The results showed that by decreasing the aspect ratio of the openings (ho/lo), the axial load in the column coupled with the wall decreases and with increasing rigidity of the link beam the shear forces in link beam increased and center of mass displacement and story drift are reduced. The strength of structural wall components becomes different in pull/push loading direction due to the eccentric opening location. Also, seven buildings have been compared, decreasing the wall aspect ratio from the axial forces in the column and shear forces in the link beam decreases. The strong earthquakes recorded worldwide have shown that the damages and the failure mechanisms of the reinforced concrete structural walls depend on a series of factors, such as the shape in plan and elevation, the dimensions of the walls and openings. During the past several decades, extensive experimental and analytical studies have been conducted on the behavior of structural walls with openings. This paper describes an analytical study carried out on of reinforced concrete walls with eccentric opening. In order to achieve this goal, variations in various parameters including changes in the aspect ratio of the openings, the stiffness of the link beam, the aspect ratio of the openings with simple connection at the both end of link beams and the aspect ratio of the walls are studied. Story drift, center of mass displacement, shear and moment in coupling beams and axial load in columns which coupled with shear wall are analyzed and compared together. The results showed that by decreasing the aspect ratio of the openings (ho/lo), the axial load in the column coupled with the wall decreases and with increasing rigidity of the link beam the shear forces in link beam increased and center of mass displacement and story drift are reduced. The strength of structural wall components becomes different in pull/push loading direction due to the eccentric opening location. Also, seven buildings have been compared, decreasing the wall aspect ratio from the axial forces in the column and shear forces in the link beam decreases. https://ceej.aut.ac.ir/article_2912_c68c9c8258ea7d85472dd6fd0015f047.pdf

Amirkabir University of Technology Amirkabir Journal of Civil Engineering 2588-297X 51 5 2019 12 22 The continuous water temperature monitoring by using Acoustic Tomography Technology The continuous water temperature monitoring by using Acoustic Tomography Technology 1097 1108 2979 10.22060/ceej.2018.14381.5639 FA Masoud Bahreinimotlagh Assistant Professor, Water Research Institute 0000-0001-9009-663X Reza Roozbahani Department of Water resources studies and research, Water Research Institute, Tehran, Iran Mohammad Javad Zareian Department of Water resources studies and research, Water Research Institute, Tehran, Iran Hamid Kardan Moghadam Department of Water resources studies and research, Water Research Institute, Tehran, Iran Kamal Mohtasham SanjAb Fannavari Khanlije Fars. Ltd. Journal Article 2018 04 29 Acoustic Tomography (AT) technology transmits reciprocal acoustic waves to measure the flow characteristics such as flow velocity, water temperature, suspended sediment concentration, salinity and the flow direction in rivers, dam storages, lakes, seas and the oceans. Although, this technique is widely applied in developed countries, it was not used in Iran yet. This research shows the first acoustic tomography experiment in Iran for measuring the flow velocity in a shallow lake located in the western of Shiraz City. Reciprocal sound transmissions were performed between the two acoustic stations located on both sides of the lake. The length of sound transmission line was 262 m and the central frequency was set to 30 kHz. The experiment period was 20 minutes and the acoustical data was collected at time intervals of 40s. The surface temperature was measured by a temperature sensor (accuracy= 0.1 oC) at four positions along the acoustical ray path. The results showed the arrival time of acoustic waves were approximately constant and it was 177 ms. Finally, the depth- and range-averaged sound speed and the water temperature along the ray path were estimated from the mean travel time. The temperature varied between 19.7 to 19.9 oC that was confirmed by temperature sensor data. The temperature resolution of AT technique was estimated around 0.04 oC that shows the more accuracy than the temperature sensor. The result of this study showed the ability of acoustic tomography technique to monitor the water temperature in natural aquatic environments. Acoustic Tomography (AT) technology transmits reciprocal acoustic waves to measure the flow characteristics such as flow velocity, water temperature, suspended sediment concentration, salinity and the flow direction in rivers, dam storages, lakes, seas and the oceans. Although, this technique is widely applied in developed countries, it was not used in Iran yet. This research shows the first acoustic tomography experiment in Iran for measuring the flow velocity in a shallow lake located in the western of Shiraz City. Reciprocal sound transmissions were performed between the two acoustic stations located on both sides of the lake. The length of sound transmission line was 262 m and the central frequency was set to 30 kHz. The experiment period was 20 minutes and the acoustical data was collected at time intervals of 40s. The surface temperature was measured by a temperature sensor (accuracy= 0.1 oC) at four positions along the acoustical ray path. The results showed the arrival time of acoustic waves were approximately constant and it was 177 ms. Finally, the depth- and range-averaged sound speed and the water temperature along the ray path were estimated from the mean travel time. The temperature varied between 19.7 to 19.9 oC that was confirmed by temperature sensor data. The temperature resolution of AT technique was estimated around 0.04 oC that shows the more accuracy than the temperature sensor. The result of this study showed the ability of acoustic tomography technique to monitor the water temperature in natural aquatic environments. https://ceej.aut.ac.ir/article_2979_2d71b2ae158c7c5912cc0bbde2bb9d95.pdf