University of Tabriz Journal of Civil and Environmental Engineering 2008-7918 45 81 2016 02 20 Studying the Effect of Size and Moisture of Particles and Mulch Polyacrylic Acid on the Amount of Wind Erosion Studying the Effect of Size and Moisture of Particles and Mulch Polyacrylic Acid on the Amount of Wind Erosion 1 6 4567 FA Nahideh Eshaghi Sardroud Faculty of Civil Engineering, University of Tabriz Hooshang Katebi Faculty of Civil Engineering, University of Tabriz Abdolreza Mirmohseni bFaculty of chemistry, University of Tabriz Journal Article 2016 03 08 Wind erosion is a major environmental problem in anywhere the soil is loose, dry, and finely granulated. That is because winds can easily lift and move sands and soil particles. Wind erosion occurs when the force of wind exceeds the threshold level of soil, because the force of wind is stronger than the gravitational force holding the soil down. Wind erosion is the result of complex interactions among windvelocity, precipitation, surface roughness, soil texture. Definitely, rate of wind erosion is related to the threshold wind velocity. Threshold wind velocity is the velocity which cause the initiate move of soil particle. It depends on soil particles size, moisture, soil features. In terms of soil surface, Blanco and Lal (2008), Chepil and Milne (1941) found that soil particle size has a negative relationship on wind erosion [1, 2]. Fine and loose particles are entrained more easily than coarse particles under the same wind velocity and it is because of weight of particles. On the other hand, soil moisture is also an important factor influencing the erosion rate. There are variety ways to control wind erosion. Recently, chemical and polymeric stabilizers be used for reducing wind erosion. Various researchers got to control wind erosion by using polymers such as: Poly Vinyl Acetate (PVIN), Poly Acryl Amide (PAM) as a stabilizer in laboratory scale with wind tunnel [3]. Wind erosion is a major environmental problem in anywhere the soil is loose, dry, and finely granulated. That is because winds can easily lift and move sands and soil particles. Wind erosion occurs when the force of wind exceeds the threshold level of soil, because the force of wind is stronger than the gravitational force holding the soil down. Wind erosion is the result of complex interactions among windvelocity, precipitation, surface roughness, soil texture. Definitely, rate of wind erosion is related to the threshold wind velocity. Threshold wind velocity is the velocity which cause the initiate move of soil particle. It depends on soil particles size, moisture, soil features. In terms of soil surface, Blanco and Lal (2008), Chepil and Milne (1941) found that soil particle size has a negative relationship on wind erosion [1, 2]. Fine and loose particles are entrained more easily than coarse particles under the same wind velocity and it is because of weight of particles. On the other hand, soil moisture is also an important factor influencing the erosion rate. There are variety ways to control wind erosion. Recently, chemical and polymeric stabilizers be used for reducing wind erosion. Various researchers got to control wind erosion by using polymers such as: Poly Vinyl Acetate (PVIN), Poly Acryl Amide (PAM) as a stabilizer in laboratory scale with wind tunnel [3].

https://ceej.tabrizu.ac.ir/article_4567_c1797e8179ce9fb29a8cfab96ce1389d.pdf

University of Tabriz Journal of Civil and Environmental Engineering 2008-7918 45 81 2016 02 20 Impact of Heavy Metal Contaminants on Coefficient of Variations of Compression Index, Expansion Index and Permeability Coefficient of Bentonite from Micro-Structural Point of View Impact of Heavy Metal Contaminants on Coefficient of Variations of Compression Index, Expansion Index and Permeability Coefficient of Bentonite from Micro-Structural Point of View 7 17 4677 FA Vahid Reza Ouhadi Faculty of Civil Engineering, Bu-Ali Sina University Salaheddin Hamidi Faculty of Civil Engineering, Bu-Ali Sina University Mohammad Amiri Faculty of Engineering, Hormozgan University Journal Article 2016 04 11

https://ceej.tabrizu.ac.ir/article_4677_0bc9caa86ff2bb9c54f6e093a4b18cbb.pdf

University of Tabriz Journal of Civil and Environmental Engineering 2008-7918 45 81 2016 02 20 Experimental Study of the Effect of Roughness on the Velocity and Concentration Profiles of Sedimentary Density Current Body Experimental Study of the Effect of Roughness on the Velocity and Concentration Profiles of Sedimentary Density Current Body 19 28 4675 FA Mehdi Daryaee Faculty of Water Sciences and Engineering, University of Shahid Chamran Seyed Mahmoud Kashefipour Faculty of Water Sciences and Engineering, University of Shahid Chamran Mehdi Ghomshi Faculty of Water Sciences and Engineering, University of Shahid Chamran Journal Article 2016 04 11 One of the most important phenomena in the nature with many undesirable effects for the environment is density current. Density or gravity current is a flow with a density of , which is higher than the ambient fluid with density of . This density difference causes a reduction in gravity g in the form of ). A schematic figure of a density current is shown in Fig. 1. One of the most important phenomena in the nature with many undesirable effects for the environment is density current. Density or gravity current is a flow with a density of , which is higher than the ambient fluid with density of . This density difference causes a reduction in gravity g in the form of ). A schematic figure of a density current is shown in Fig. 1.

https://ceej.tabrizu.ac.ir/article_4675_4669b12ce5ff131385c961ce8feb8233.pdf

University of Tabriz Journal of Civil and Environmental Engineering 2008-7918 45 81 2016 02 20 Application of a New Cylindrical Slit Damper for Mitigation of Structural Vibrations Application of a New Cylindrical Slit Damper for Mitigation of Structural Vibrations 29 43 4678 FA Habib Saeed Monir Faculty of Civil Engineering, University of Urmia Neda Fazalipoor Faculty of Civil Engineering, University of Urmia Journal Article 2016 04 11 This study introduces a new kind of steel slit damper which can be installed diagonally in steel frames as a brace-type vibration damper. This new damper consists of three standard cylindrical tubes which have been placed inside of each other. On the middle tube wall, several long slotted holes are created in a manner that under seismic excitation, axial forces are created in the braces and then by its transmission to the tubes, narrow strips between these long slotted holes are yielded and therefore energy is dissipated through shear/flexural yielding. The inner and the external tubes will prevent the out of plane deformation of the middle tube. For fixing these tubes to each other and limiting the forward and backward movement of the middle tube, two long slotted holes have been created on the tubes walls. In comparison to the other available brace-type dampers, such as buckling restrained brace, this damper is simpler and costs less. The yielding part of this modified damper can be easily inspected after an earthquake. This damper was analyzed in ABAQUS and its hysteresis curve and the effects of its mechanical characteristics such as strip length, strip depth, strip thickness were obtained. For checking the effectiveness of device in mitigation of structural responses, the model of a 5-story frame, which was already designed under Iranian 2800 seismic code, was created in SAP2000. Then this structure, with and without damper was analyzed under different ground motions such as Tabas, Kobe and Elcentro. The results were indicating that the lateral displacements and the base shears of the multi-story building have been significantly reduced This study introduces a new kind of steel slit damper which can be installed diagonally in steel frames as a brace-type vibration damper. This new damper consists of three standard cylindrical tubes which have been placed inside of each other. On the middle tube wall, several long slotted holes are created in a manner that under seismic excitation, axial forces are created in the braces and then by its transmission to the tubes, narrow strips between these long slotted holes are yielded and therefore energy is dissipated through shear/flexural yielding. The inner and the external tubes will prevent the out of plane deformation of the middle tube. For fixing these tubes to each other and limiting the forward and backward movement of the middle tube, two long slotted holes have been created on the tubes walls. In comparison to the other available brace-type dampers, such as buckling restrained brace, this damper is simpler and costs less. The yielding part of this modified damper can be easily inspected after an earthquake. This damper was analyzed in ABAQUS and its hysteresis curve and the effects of its mechanical characteristics such as strip length, strip depth, strip thickness were obtained. For checking the effectiveness of device in mitigation of structural responses, the model of a 5-story frame, which was already designed under Iranian 2800 seismic code, was created in SAP2000. Then this structure, with and without damper was analyzed under different ground motions such as Tabas, Kobe and Elcentro. The results were indicating that the lateral displacements and the base shears of the multi-story building have been significantly reduced

https://ceej.tabrizu.ac.ir/article_4678_6af93e0c6f072d94ea2e087af8a2fb3d.pdf

University of Tabriz Journal of Civil and Environmental Engineering 2008-7918 45 81 2016 02 20 The Effect of Aggregate Gradation on Performance of Asphalt Mixture The Effect of Aggregate Gradation on Performance of Asphalt Mixture 45 57 4564 FA Ebrahim Sangsefidi Faculty of Civil Engineering, Iran University of Science and Technology Maryam Sangsefidi School of Engineering, Ferdowsi University of Mashhad Hasan Ziari of Civil Engineering, Iran University of Science and Technology Journal Article 2016 03 08 An adequate and economical design for a pavement structure is just as important as a design for any other engineering structure [1]. It is possible to improve the characteristics of the asphalt mixture, using its components, aggregates and bitumen. Aggregates make up high proportion of volume and mass of asphalt mix; hence, it is predicted to have an enormous impact on the mixture properties. Major characteristics of aggregate are stiffness, shape, texture and gradation, that only gradation can be changed for a special mine. Aggregate gradation is the distribution of particle sizes expressed as a percentage of the total weight [2] and considered as the centerpiece property of aggregate which needs a careful consideration due to its effect on mix properties and performance of HMA mixtures, including air void, stability, stiffness, durability, permeability, workability, fatigue resistance, frictional resistance, resistance to moisture damage [1, 2] and also rutting resistance of asphalt concrete under traffic and environmental loads. So this parameter is considered as a very important parameter in the process of mixture design. An adequate and economical design for a pavement structure is just as important as a design for any other engineering structure [1]. It is possible to improve the characteristics of the asphalt mixture, using its components, aggregates and bitumen. Aggregates make up high proportion of volume and mass of asphalt mix; hence, it is predicted to have an enormous impact on the mixture properties. Major characteristics of aggregate are stiffness, shape, texture and gradation, that only gradation can be changed for a special mine. Aggregate gradation is the distribution of particle sizes expressed as a percentage of the total weight [2] and considered as the centerpiece property of aggregate which needs a careful consideration due to its effect on mix properties and performance of HMA mixtures, including air void, stability, stiffness, durability, permeability, workability, fatigue resistance, frictional resistance, resistance to moisture damage [1, 2] and also rutting resistance of asphalt concrete under traffic and environmental loads. So this parameter is considered as a very important parameter in the process of mixture design.

https://ceej.tabrizu.ac.ir/article_4564_16a8133e61c772136caf07d2757e6420.pdf

University of Tabriz Journal of Civil and Environmental Engineering 2008-7918 45 81 2016 02 20 Seismic Behavior of Tensegrity Barrel Vaults Seismic Behavior of Tensegrity Barrel Vaults 59 68 4565 FA Farid Seifollahi Civil Engineering Department Faculty of Engineering, Azarbaijan Shahid Madani University Arjang Sadeghi Civil Engineering Department Faculty of Engineering, Azarbaijan Shahid Madani University Journal Article 2016 03 08 Space structures are mostly interested for their lightness. One of the recent branches of space structures are called tensegrity structures. These structures are composed of compression bars and prestressed cables. There are not sufficient works about dynamic characteristics and behavior of these structures. Sultan et al carried out some research on nonlinear dynamic behavior of these structures [1]. Ben Kahla and Moussa studied the dynamic effects of rupture of a cable in an expanded tetrahedron [2]. Ben Kahla also has carried out a numerical analysis study of seismic behavior of a tensegrity frame[3]. Following these studies, in this research a set of tensegrity barrel vaults are considered and their seismic behavior is studied. Space structures are mostly interested for their lightness. One of the recent branches of space structures are called tensegrity structures. These structures are composed of compression bars and prestressed cables. There are not sufficient works about dynamic characteristics and behavior of these structures. Sultan et al carried out some research on nonlinear dynamic behavior of these structures [1]. Ben Kahla and Moussa studied the dynamic effects of rupture of a cable in an expanded tetrahedron [2]. Ben Kahla also has carried out a numerical analysis study of seismic behavior of a tensegrity frame[3]. Following these studies, in this research a set of tensegrity barrel vaults are considered and their seismic behavior is studied.

https://ceej.tabrizu.ac.ir/article_4565_1c2c945c21259aeb320529b4ecd06cc2.pdf

University of Tabriz Journal of Civil and Environmental Engineering 2008-7918 45 81 2016 02 20 Fire Following Earthquake Hazard Analysis of Gas Pipeline Using Monte Carlo Simulation (Case Study: District No. 20 of Tehran Metropolitan) Fire Following Earthquake Hazard Analysis of Gas Pipeline Using Monte Carlo Simulation (Case Study: District No. 20 of Tehran Metropolitan) 69 80 4566 FA Alireza Sadeghian Faculty of Environment, University of Tehran Babak Omidvar Faculty of Environment, University of Tehran Esmail Salehi Faculty of Environment, University of Tehran Journal Article 2016 03 08 The experiences of past earthquakes show that if a gas system is affected by severe and sudden damages of earthquake, gas leakage may cause extensive fire, massive explosions and consequently significant human fatalities and casualties. The importance of this issue is so that Byerly has indicated that fires following major earthquakes are so common that it should be considered as the complementary part of earthquake [1]. Due to the long lifetime of gas pipelines in district No. 20 of Tehran, and, in some cases, the passing of gas pipes across the existing faults or in close proximity, this municipal district has a high damage potential in times of probable disasters, such as earthquakes and subsequent fires. Therefore, in this research a numerical analysis method for the estimation of ignition probability of gas pipelines following an earthquake in district No. 20 of Tehran is presented. The experiences of past earthquakes show that if a gas system is affected by severe and sudden damages of earthquake, gas leakage may cause extensive fire, massive explosions and consequently significant human fatalities and casualties. The importance of this issue is so that Byerly has indicated that fires following major earthquakes are so common that it should be considered as the complementary part of earthquake [1]. Due to the long lifetime of gas pipelines in district No. 20 of Tehran, and, in some cases, the passing of gas pipes across the existing faults or in close proximity, this municipal district has a high damage potential in times of probable disasters, such as earthquakes and subsequent fires. Therefore, in this research a numerical analysis method for the estimation of ignition probability of gas pipelines following an earthquake in district No. 20 of Tehran is presented.

https://ceej.tabrizu.ac.ir/article_4566_e8ff367147ab96b7782f842e850ab225.pdf

University of Tabriz Journal of Civil and Environmental Engineering 2008-7918 45 81 2016 02 20 Double Domes Free Form Space Structures: Stability Behavior and Imperfection Sensitivity Analysis Double Domes Free Form Space Structures: Stability Behavior and Imperfection Sensitivity Analysis 81 95 4679 FA Seyed Mehdi Abbasi Mousavi Faculty of Civil Engineering, Sahand University of Technology Karim Abedi Faculty of Civil Engineering, Sahand University of Technology Mohamad-Reza Chenaghlou Faculty of Civil Engineering, Sahand University of Technology Journal Article 2016 04 11 Free forms are usually used to refer double curve surfaces which are independent from groups of geometrically or mechanically constrained forms. Geometrically constrained forms are only conditioned by a geometrical definition, like it could be done on basis of simple surfaces. When there is a close relationship between forms and forces, the forms are mechanically constrained [1]. In the present study, behavior of double domes free form single layer space structures as a group of free form structures are investigated. Gaussian curvature of double domes can be positive and negative, unlike regular domes. In single layer reticulated space structures, local instability with nodal snap-through phenomenon could result in propagation in whole structure [2], so stability behavior of double domes free form single layer space structures should be investigated. The parametric study is performed in order to evaluate the effects of different variables on the stability behavior of double domes free form space structures. Free forms are usually used to refer double curve surfaces which are independent from groups of geometrically or mechanically constrained forms. Geometrically constrained forms are only conditioned by a geometrical definition, like it could be done on basis of simple surfaces. When there is a close relationship between forms and forces, the forms are mechanically constrained [1]. In the present study, behavior of double domes free form single layer space structures as a group of free form structures are investigated. Gaussian curvature of double domes can be positive and negative, unlike regular domes. In single layer reticulated space structures, local instability with nodal snap-through phenomenon could result in propagation in whole structure [2], so stability behavior of double domes free form single layer space structures should be investigated. The parametric study is performed in order to evaluate the effects of different variables on the stability behavior of double domes free form space structures.

https://ceej.tabrizu.ac.ir/article_4679_92177d1357e4aa80bb98680312d3a61c.pdf

University of Tabriz Journal of Civil and Environmental Engineering 2008-7918 45 81 2016 02 20 Field Study of the Effect of Grout Pressure on Tensile Strength and Creep Behavior of Grout Nails in Green Marl Field Study of the Effect of Grout Pressure on Tensile Strength and Creep Behavior of Grout Nails in Green Marl 97 106 4680 FA Gholam Moradi Faculty of Civil Engineering, University of Tabriz Siamak Zadkarim Faculty of Civil Engineering, University of Tabriz Journal Article 2016 04 11 One of the most important problems and challenges in civil engineering is constructing structures, protecting excavation and the building in their surrounding and stabilizing embankments. Non-observing proper methods for protecting deeps and also constructing slopes will lead to irreparable damage and the risks resulted from probable subsidence and reducing the bearing capacity and lateral displacements will cause cracks in neighbouring structures of deep has been Described by FHWA (1998). Studying the nails behavior in marl and clay soils which are considered as fine-grained soils with different properties compared to grained soils are the subjects which has been considered less. High plastic properties, semi-saturation state, changing its behavior in long-term, very low grouting and other similar cases are among the problems which necessitates studying the nail function in these types of soils. One of the most important problems and challenges in civil engineering is constructing structures, protecting excavation and the building in their surrounding and stabilizing embankments. Non-observing proper methods for protecting deeps and also constructing slopes will lead to irreparable damage and the risks resulted from probable subsidence and reducing the bearing capacity and lateral displacements will cause cracks in neighbouring structures of deep has been Described by FHWA (1998). Studying the nails behavior in marl and clay soils which are considered as fine-grained soils with different properties compared to grained soils are the subjects which has been considered less. High plastic properties, semi-saturation state, changing its behavior in long-term, very low grouting and other similar cases are among the problems which necessitates studying the nail function in these types of soils. https://ceej.tabrizu.ac.ir/article_4680_12a877c8cd3cb8eba44dca0f51e5ae20.pdf

University of Tabriz Journal of Civil and Environmental Engineering 2008-7918 45 81 2016 02 20 Elephant Foot Buckling and Retrofitting of Steel Thin Walled Cylindrical Shells Using FRP Composite Materials Elephant Foot Buckling and Retrofitting of Steel Thin Walled Cylindrical Shells Using FRP Composite Materials 107 117 4676 FA Morteza Vakili Department of Civil Engineering, Urmia University Hossein Showkati Department of Civil Engineering, Urmia University Journal Article 2016 04 11 Steel tanks designed in cylindrical forms are one of the shell structures which are widely used in industrial facilities. In geometric terms, these tanks have a very small thickness compared to the other dimensions and thus are categorized as thin walled structures which should consider the buckling failures. The buckling failure of tanks containing liquids is possible in various modes. In this paper instability of cylindrical shell wall which occurs under simultaneous loading of axial compression and high internal pressure, is considered. This instability generally occurs near the base. The present study demonstrates that increasing the internal pressure and the yielding of the wall near the base, decreases flexural stiffness and increases the local displacement of the cylindrical shells. In other words, the resultant circumferential membrane stress increases and inelastic buckling occurs. This instability near the base is known as “Elephant Foot Buckling”. This paper provides a proposal for strengthening cylindrical shells against elephant foot buckling using FRP. Some efforts have been done on this subject [1-3]. The aim of this paper is to investigate the strengthening of thin metallic cylindrical shells by local application of FRP to increase the elephant’s foot buckling strength. Finite element analysis of shells has been used in the present paper in order to obtain the effect of strengthening tanks using FRP on the increase of elephant foot buckling resistance. In order to achieve the behavior of cylindrical shell when being strengthened by FRP, accurate modeling of composite fibers and adhesive has been applied, and its appropriate dimensions and locations are presented. Steel tanks designed in cylindrical forms are one of the shell structures which are widely used in industrial facilities. In geometric terms, these tanks have a very small thickness compared to the other dimensions and thus are categorized as thin walled structures which should consider the buckling failures. The buckling failure of tanks containing liquids is possible in various modes. In this paper instability of cylindrical shell wall which occurs under simultaneous loading of axial compression and high internal pressure, is considered. This instability generally occurs near the base. The present study demonstrates that increasing the internal pressure and the yielding of the wall near the base, decreases flexural stiffness and increases the local displacement of the cylindrical shells. In other words, the resultant circumferential membrane stress increases and inelastic buckling occurs. This instability near the base is known as “Elephant Foot Buckling”. This paper provides a proposal for strengthening cylindrical shells against elephant foot buckling using FRP. Some efforts have been done on this subject [1-3]. The aim of this paper is to investigate the strengthening of thin metallic cylindrical shells by local application of FRP to increase the elephant’s foot buckling strength. Finite element analysis of shells has been used in the present paper in order to obtain the effect of strengthening tanks using FRP on the increase of elephant foot buckling resistance. In order to achieve the behavior of cylindrical shell when being strengthened by FRP, accurate modeling of composite fibers and adhesive has been applied, and its appropriate dimensions and locations are presented.

https://ceej.tabrizu.ac.ir/article_4676_116a70fdc5ed5775b9f3e405634fdcce.pdf