Amirkabir University of Technology Amirkabir Journal of Civil Engineering 2588-297X 49 1 2017 05 22 The Relative Stiffness of Steel Eccentric Braced Frame with Dual Vertical Links The Relative Stiffness of Steel Eccentric Braced Frame with Dual Vertical Links 3 12 682 10.22060/ceej.2016.682 FA S. Sabouri-Ghomi Civil Engineering Faculty, K. N. Toosi University of Technology, Tehran, Iran 0000-0002-8047-4980 B. Saadati Civil Engineering Faculty, K. N. Toosi University of Technology, Tehran, Iran Journal Article 2013 09 16 The most important characteristics of building frames can be abbreviated in stiffness, strength and ductility. Moment frames have ductile behavior and low stiffness; therefore, the main reason in using the lateral bracing systems is their considerable stiffness. Eccentric bracing systems are considered as ductile frames, while satisfying the required stiffness. The lateral stiffness of conventional eccentric configurations have been calculated previously. In this research, the lateral relative stiffness of eccentrically braced frame with dual vertical links (EBF-DVL) is calculated analytically. EBF-DVL has two parallel vertical links which are welded to the floor beam at the top and to one horizontal link at the bottom. In order to provide the required equations for obtaining the stiffness, the slope-deflection equations are used by considering the effects of shear deformations. The results show that EBF-DVL has a high relative stiffness and by adjusting the lengths of vertical and horizontal links, it is possible to achieve the stiffness even more than the stiffness of eccentric bracing with horizontal link between two diagonal braces. Although an increase in either the moment of inertia or shear area of the vertical link leads to an increase in the lateral stiffness of the system, the effective interval for increasing the moment of inertia of the vertical links is to be limited to approximately half of the column moment of inertia and the corresponding value for increasing the shear area is approximately 60% of the shear area of the column. The most important characteristics of building frames can be abbreviated in stiffness, strength and ductility. Moment frames have ductile behavior and low stiffness; therefore, the main reason in using the lateral bracing systems is their considerable stiffness. Eccentric bracing systems are considered as ductile frames, while satisfying the required stiffness. The lateral stiffness of conventional eccentric configurations have been calculated previously. In this research, the lateral relative stiffness of eccentrically braced frame with dual vertical links (EBF-DVL) is calculated analytically. EBF-DVL has two parallel vertical links which are welded to the floor beam at the top and to one horizontal link at the bottom. In order to provide the required equations for obtaining the stiffness, the slope-deflection equations are used by considering the effects of shear deformations. The results show that EBF-DVL has a high relative stiffness and by adjusting the lengths of vertical and horizontal links, it is possible to achieve the stiffness even more than the stiffness of eccentric bracing with horizontal link between two diagonal braces. Although an increase in either the moment of inertia or shear area of the vertical link leads to an increase in the lateral stiffness of the system, the effective interval for increasing the moment of inertia of the vertical links is to be limited to approximately half of the column moment of inertia and the corresponding value for increasing the shear area is approximately 60% of the shear area of the column. https://ceej.aut.ac.ir/article_682_08d98638c6fcd194a4b1e6992063e944.pdf

Amirkabir University of Technology Amirkabir Journal of Civil Engineering 2588-297X 49 1 2017 05 22 Evaluation of Ductility of Bearing Concrete Wall Systems with Regard to Their Boundary Element Evaluation of Ductility of Bearing Concrete Wall Systems with Regard to Their Boundary Element 13 22 923 10.22060/ceej.2017.10468.4896 FA A. R. Rahai Department of Civil and Environmental Engineering, Amirkabir University of Technology, Tehran, Iran 0000-0002-9101-0794 Seyed Hadi Rashedi Department of Civil and Environmental Engineering, Amirkabir University of Technology, Tehran, Iran 0009-0002-0737-2512 Journal Article 2015 04 25 Bearing reinforced concrete wall system has<br />Bearing reinforced concrete wall system has a vast usage, due to its good performance in past earthquakes. In this paper, with the aim of evaluating bearing wall performance, nonlinear static analysis based on several assumptions drawing upon experimental research is used. To ensure the accuracy of modeling by fiber section method, the analysis results have been validated by the results of an experimental model of RC bearing wall. To evaluate the reduction factor and ductility level of bearing reinforced concrete wall systems, a vast study on several models with different stories were performed. The results indicated that, the components of the boundary element have a limit effect on the models’ ductility factor. Also, calculated reduction factors for models with increasing building height up to a height of about 50 meters, show acceptable values and at more elevations, decreasing procedure of this coefficient has increased. Bearing reinforced concrete wall system has<br />Bearing reinforced concrete wall system has a vast usage, due to its good performance in past earthquakes. In this paper, with the aim of evaluating bearing wall performance, nonlinear static analysis based on several assumptions drawing upon experimental research is used. To ensure the accuracy of modeling by fiber section method, the analysis results have been validated by the results of an experimental model of RC bearing wall. To evaluate the reduction factor and ductility level of bearing reinforced concrete wall systems, a vast study on several models with different stories were performed. The results indicated that, the components of the boundary element have a limit effect on the models’ ductility factor. Also, calculated reduction factors for models with increasing building height up to a height of about 50 meters, show acceptable values and at more elevations, decreasing procedure of this coefficient has increased. https://ceej.aut.ac.ir/article_923_c4015b7f368e6b4871809f49debe0579.pdf

Amirkabir University of Technology Amirkabir Journal of Civil Engineering 2588-297X 49 1 2017 05 22 Investigation of the Effect of Alkalai- Silica Reaction on Structural Behavior of Reinforced Concrete Beams Using the Finite Element Method Investigation of the Effect of Alkalai- Silica Reaction on Structural Behavior of Reinforced Concrete Beams Using the Finite Element Method 23 34 701 10.22060/ceej.2016.701 FA S. Hajighasemali Department of Civil Engineering, Islamic Azad University (Roudehen Branch), Tehran, Iran A. A. Ramezanianpour Faculty of Civil Engineering, Amirkabir University of Technology, Tehran, Iran V. Lotfi Faculty of Civil Engineering, Amirkabir University of Technology, Tehran, Iran M. H. Kashefizadeh Department of Civil Engineering, UTM University of Malaysia, Skudai, Malaysia Journal Article 2013 11 17 Many structures, such as dams, bridges and hydraulic structures, suffer deterioration induced by the alkali-aggregate reaction (AAR), which impairs the durability and safety of installations. ASR is an internal chemical reaction between certain forms of siliceous aggregates and alkaline pore solution in concrete. The result is a more or less crystallised silico-alkaline product which can exert pressure on the surrounding matrix. ASR induces concrete expansion and generally leads to loss of strength and cracking. The structural behaviour of concrete which has been effected by the alkali-silica reaction (ASR) is difficult to model due to various random parameters that govern this chemical process. The aim of this paper is to investigate the effect of ASR on the behaviour of reinforced concrete beams using three methods: an experimental model, conventional structural analysis and the finite element method. For this purpose, 100 x 150 x 1100-mm concrete beams were built in the laboratory and reinforced with different ratios of compression and tension bars. Then ASR and creep strains were modelled by reducing the elastic modulus of the concrete and applying an equivalent tension force. For the purposes of verifying the numerical methods involved, fourteen beams were conditioned in a suitable environment using similar dimensions and loading systems. Experimental results on reactive concrete samples were simulated so as to test whether the model was capable of describing the behaviour of affected reinforced concrete beams under service loads. The comparison revealed that the finite element model had good compatibility with the acquired test results. Many structures, such as dams, bridges and hydraulic structures, suffer deterioration induced by the alkali-aggregate reaction (AAR), which impairs the durability and safety of installations. ASR is an internal chemical reaction between certain forms of siliceous aggregates and alkaline pore solution in concrete. The result is a more or less crystallised silico-alkaline product which can exert pressure on the surrounding matrix. ASR induces concrete expansion and generally leads to loss of strength and cracking. The structural behaviour of concrete which has been effected by the alkali-silica reaction (ASR) is difficult to model due to various random parameters that govern this chemical process. The aim of this paper is to investigate the effect of ASR on the behaviour of reinforced concrete beams using three methods: an experimental model, conventional structural analysis and the finite element method. For this purpose, 100 x 150 x 1100-mm concrete beams were built in the laboratory and reinforced with different ratios of compression and tension bars. Then ASR and creep strains were modelled by reducing the elastic modulus of the concrete and applying an equivalent tension force. For the purposes of verifying the numerical methods involved, fourteen beams were conditioned in a suitable environment using similar dimensions and loading systems. Experimental results on reactive concrete samples were simulated so as to test whether the model was capable of describing the behaviour of affected reinforced concrete beams under service loads. The comparison revealed that the finite element model had good compatibility with the acquired test results. https://ceej.aut.ac.ir/article_701_b4a528955b84f584974e92d025a75d1f.pdf

Amirkabir University of Technology Amirkabir Journal of Civil Engineering 2588-297X 49 1 2017 05 22 Changes in Self-Purification Capacity of the Ahvaz Karun River in 2008 and 2014 using QUAL2Kw Model Changes in Self-Purification Capacity of the Ahvaz Karun River in 2008 and 2014 using QUAL2Kw Model 35 46 691 10.22060/ceej.2016.691 FA P. Hoseini Faculty of Natural Resources and Environments, Department of Environment, Malayer University, Malayer, Iran Y. Hoseini 0000-0003-0292-172X Journal Article 2013 07 19 The Karun River receives large quantities of domestic wastewater, industrial effluents, and agricultural drainage water during its course. Since every river has a certain capacity for accepting incoming pollutants and for self-purification, knowledge of the trend of changes in self-purification capacity is of great importance. This research studied changes in the self-purification capacity of the Karun River in the 42-kilometer distance between the Zergan and Kot Amir stations in 2008-2009 and 2013-2014. Changes in the parameters of pH, EC, and BOD in these two years were first simulated for the two months of August and January using the calibrated Qual2Kw model. The observed data was then compared with the calculated data using the square of the correlation coefficient (R2) and the mean absolute error (MAE). Results showed the Karun River could not purify itself with respect to the EC parameter in 2008-2009 and with respect to the BOD parameter in 2013-2014. Moreover, the best simulation of the model was achieved for the pH parameter, and the simulations for the BOD and EC parameters were the second and third best, respectively. The Karun River receives large quantities of domestic wastewater, industrial effluents, and agricultural drainage water during its course. Since every river has a certain capacity for accepting incoming pollutants and for self-purification, knowledge of the trend of changes in self-purification capacity is of great importance. This research studied changes in the self-purification capacity of the Karun River in the 42-kilometer distance between the Zergan and Kot Amir stations in 2008-2009 and 2013-2014. Changes in the parameters of pH, EC, and BOD in these two years were first simulated for the two months of August and January using the calibrated Qual2Kw model. The observed data was then compared with the calculated data using the square of the correlation coefficient (R2) and the mean absolute error (MAE). Results showed the Karun River could not purify itself with respect to the EC parameter in 2008-2009 and with respect to the BOD parameter in 2013-2014. Moreover, the best simulation of the model was achieved for the pH parameter, and the simulations for the BOD and EC parameters were the second and third best, respectively. https://ceej.aut.ac.ir/article_691_10a5ab2db37feedfdeaab192ead4ac0e.pdf

Amirkabir University of Technology Amirkabir Journal of Civil Engineering 2588-297X 49 1 2017 05 22 Prioritization of Water Consumption Management Strategies in Water Distribution Networks Using Multiple Criteria Decision Making Method of Fuzzy Analytic Hierarchy Process (Case Study: Tehran) Prioritization of Water Consumption Management Strategies in Water Distribution Networks Using Multiple Criteria Decision Making Method of Fuzzy Analytic Hierarchy Process (Case Study: Tehran) 47 56 379 10.22060/ceej.2015.379 FA M. Tabesh School of Civil Engineering, College of Engineering, University of Tehran, Tehran, Iran 0000-0002-8982-8941 E. Ali-Bariany School of Civil Engineering, College of Engineering, University of Tehran, Tehran, Iran S. S. Motevallian School of Civil Engineering, College of Engineering, University of Tehran, Tehran, Iran A. Roozbahani College of Abourayhan, University of Tehran, Tehran, Iran S. Beygi School of Civil Engineering, College of Engineering, University of Tehran, Tehran, Iran Journal Article 2013 09 23 As the volume of renewable water resources has been significantly decreased and developing new water resources are faced with serious limitations, there has been a change of emphasis in management practices from supply-sided to demand-sided approaches in most regions of the world. Water consumption management strategies seek to reduce water consumption and establish a reasonable and sustainable balance between water supply and demand. In this paper, a multi-attribute decisionmaking method and an algorithm is developed for selecting water consumption management strategies for water distribution networks. To demonstrate the applicability of suggested method, a case study is conducted in Tehran in which different water consumption management strategies are prioritized using Fuzzy Analytic Hierarchy Process (FAHP) and based on water and wastewater experts’ judgments. Applied strategies are performing educational programs among water users, non-revenue water reduction, increasing water price and using water-saving appliances. Furthermore, decision criteria used in this study are costs, time of implementation, water user’s satisfaction, the volume of non-revenue water and water-saving efficacy. To evaluate the impact of uncertainties lied in the model on final results, a sensitivity analysis is performed in terms of changes in the weight of decision-makers’ judgments and the shape of fuzzy membership functions. Finally, the non-revenue water reduction is gained the first rank among all water consumption management strategies. The results of this study show that in case of high degree of fuzzy uncertainties and dearth of sufficient quantitative data, the presented method can be employed as a robust decision-making tool by urban water managers. As the volume of renewable water resources has been significantly decreased and developing new water resources are faced with serious limitations, there has been a change of emphasis in management practices from supply-sided to demand-sided approaches in most regions of the world. Water consumption management strategies seek to reduce water consumption and establish a reasonable and sustainable balance between water supply and demand. In this paper, a multi-attribute decisionmaking method and an algorithm is developed for selecting water consumption management strategies for water distribution networks. To demonstrate the applicability of suggested method, a case study is conducted in Tehran in which different water consumption management strategies are prioritized using Fuzzy Analytic Hierarchy Process (FAHP) and based on water and wastewater experts’ judgments. Applied strategies are performing educational programs among water users, non-revenue water reduction, increasing water price and using water-saving appliances. Furthermore, decision criteria used in this study are costs, time of implementation, water user’s satisfaction, the volume of non-revenue water and water-saving efficacy. To evaluate the impact of uncertainties lied in the model on final results, a sensitivity analysis is performed in terms of changes in the weight of decision-makers’ judgments and the shape of fuzzy membership functions. Finally, the non-revenue water reduction is gained the first rank among all water consumption management strategies. The results of this study show that in case of high degree of fuzzy uncertainties and dearth of sufficient quantitative data, the presented method can be employed as a robust decision-making tool by urban water managers. https://ceej.aut.ac.ir/article_379_a02ffd91ece5e7efeb46db8f10a74059.pdf

Amirkabir University of Technology Amirkabir Journal of Civil Engineering 2588-297X 49 1 2017 05 22 Study of permeability coefficient and inflow rate effects on hydraulic fracturing in saturated porous media Study of permeability coefficient and inflow rate effects on hydraulic fracturing in saturated porous media 57 66 572 10.22060/ceej.2016.572 FA O. R. Barani Faculty of Civil Engineering, K.N.Toosi University of Technology, Tehran, Iran F. Dastjerdy Faculty of Civil Engineering, K.N.Toosi University of Technology, Tehran, Iran F. Kalantary Faculty of Civil Engineering, K.N.Toosi University of Technology, Tehran, Iran Journal Article 2013 12 27 In this paper, a finite element model is developed for the fully hydro-mechanical analysis of hydraulic fracturing in saturated porous media. The model is derived within the framework of generalized Biot theory. The fracture propagation is governed by a cohesive fracture model. The flow within the fracture zone is modeled considering the lubrication equation. In order to describe the fracture in the saturated porous media, momentum equation and mass balance equation with Darcy law are employed. The standard Galerkin method and Newmark scheme are used for discretization in space and time, respectively. Finally, the effects of permeability and rate of injection on the hydraulic fracture propagation are studied. It is observed that an increase in permeability leads to slower crack propagation. In addition, increasing flow rate leads to a faster crack propagation. When permeability increases by 3.3 times, CMOD and crack length decreases by 43.8% and 20%, ,respectively after 1 second and decreases by 29.4% and 15.9%, respectively after 6 seconds. In addition, when flow rate increases by 2, 3, and 4 times, the crack length increases by 30.5%, 55.9%, and 76.3% after one second. In this paper, a finite element model is developed for the fully hydro-mechanical analysis of hydraulic fracturing in saturated porous media. The model is derived within the framework of generalized Biot theory. The fracture propagation is governed by a cohesive fracture model. The flow within the fracture zone is modeled considering the lubrication equation. In order to describe the fracture in the saturated porous media, momentum equation and mass balance equation with Darcy law are employed. The standard Galerkin method and Newmark scheme are used for discretization in space and time, respectively. Finally, the effects of permeability and rate of injection on the hydraulic fracture propagation are studied. It is observed that an increase in permeability leads to slower crack propagation. In addition, increasing flow rate leads to a faster crack propagation. When permeability increases by 3.3 times, CMOD and crack length decreases by 43.8% and 20%, ,respectively after 1 second and decreases by 29.4% and 15.9%, respectively after 6 seconds. In addition, when flow rate increases by 2, 3, and 4 times, the crack length increases by 30.5%, 55.9%, and 76.3% after one second. https://ceej.aut.ac.ir/article_572_e6b4b2a746ed40e1af829d1fa82daa10.pdf

Amirkabir University of Technology Amirkabir Journal of Civil Engineering 2588-297X 49 1 2017 05 22 Determination of Coefficient of Lateral Earth Pressure at Rest for Sandy Soil Using Cone Penetration Test and Artificial Neural Network Determination of Coefficient of Lateral Earth Pressure at Rest for Sandy Soil Using Cone Penetration Test and Artificial Neural Network 67 80 879 10.22060/ceej.2016.8601.4417 FA M. M. Ahmadi Department of Civil Engineering, Sharif University of Technology, Tehran, Iran N. Besharat Department of Civil Engineering, Sharif University of Technology, Tehran, Iran Journal Article 2013 08 28 The estimation of soil parameters in geotechnical practice is always an important step. Accurate prediction of sands parameters from insitu tests such as CPT is one of the most challenging problems in geotechnical engineering. In this study, using a series of reliable CPT calibration chamber test data and a system consisting of three types of neural networks, the coefficient of lateral pressure of sandy soil at rest (K0) is predicted while it has good agreement with measured data gathered in database. In this system, a series of neural networks perform some tasks and finally by strategically combining of networks, the system will be able to predict parameter (K0) with reasonable accuracy. The proposed system uses Self Organizing Map (SOM) for clustering data into training, testing and validating sets and probabilistic neural networks for classifying of sands and back propagation neural networks for conclusive function approximation. Details on the development of such a system are described in the present paper and finally results obtained by this system are compared to the available relations suggested by other researchers. The estimation of soil parameters in geotechnical practice is always an important step. Accurate prediction of sands parameters from insitu tests such as CPT is one of the most challenging problems in geotechnical engineering. In this study, using a series of reliable CPT calibration chamber test data and a system consisting of three types of neural networks, the coefficient of lateral pressure of sandy soil at rest (K0) is predicted while it has good agreement with measured data gathered in database. In this system, a series of neural networks perform some tasks and finally by strategically combining of networks, the system will be able to predict parameter (K0) with reasonable accuracy. The proposed system uses Self Organizing Map (SOM) for clustering data into training, testing and validating sets and probabilistic neural networks for classifying of sands and back propagation neural networks for conclusive function approximation. Details on the development of such a system are described in the present paper and finally results obtained by this system are compared to the available relations suggested by other researchers. https://ceej.aut.ac.ir/article_879_d516b13671a4179d9b7b458a6ebdeb92.pdf

Amirkabir University of Technology Amirkabir Journal of Civil Engineering 2588-297X 49 1 2017 05 22 Effect of slip width on the permanent displacement of earth slopes Effect of slip width on the permanent displacement of earth slopes 81 88 676 10.22060/ceej.2016.676 FA Y. Jafarian Geotechnical Engineering Research Center, International Institute of Earthquake Engineering and Seismology, Tehran, Iran A. Lashgari Department of Civil Engineering, Semnan University, Semnan, Iran Journal Article 2013 09 17 Newmark sliding block method is commonly used for estimating earthquake-induced permanent displacement of earth slopes and embankments. Since this method is a simplified dynamic analysis procedure with acceptable accuracy, it has been received considerable attention among the geotechnical practitioners. However, it has some shortcomings such as neglecting system response and sliding mass rotation. Hence, researchers have proposed modified procedure to enhance the realistic features of this method. The effect of sliding mass rotation, which sets the block in a gentler condition, was previously considered by continuous increment of yield acceleration. Since the sliding mass is three dimensional in reality, smaller permanent displacement is expected when the width of block is accounted for. In this paper, width of the rotating-sliding mass is taken into account in the coupled and decoupled solution of block sliding equations. The results show that the width of the slip zone is effective on the resulting displacements. With a constant slip length, whatever slip width is reduced, yield acceleration increases and consequently difference between the modified decoupled (or modified coupled) and decoupled (or coupled) increases. Newmark sliding block method is commonly used for estimating earthquake-induced permanent displacement of earth slopes and embankments. Since this method is a simplified dynamic analysis procedure with acceptable accuracy, it has been received considerable attention among the geotechnical practitioners. However, it has some shortcomings such as neglecting system response and sliding mass rotation. Hence, researchers have proposed modified procedure to enhance the realistic features of this method. The effect of sliding mass rotation, which sets the block in a gentler condition, was previously considered by continuous increment of yield acceleration. Since the sliding mass is three dimensional in reality, smaller permanent displacement is expected when the width of block is accounted for. In this paper, width of the rotating-sliding mass is taken into account in the coupled and decoupled solution of block sliding equations. The results show that the width of the slip zone is effective on the resulting displacements. With a constant slip length, whatever slip width is reduced, yield acceleration increases and consequently difference between the modified decoupled (or modified coupled) and decoupled (or coupled) increases. https://ceej.aut.ac.ir/article_676_dc6a70712a252123c40d2adba6a11d84.pdf

Amirkabir University of Technology Amirkabir Journal of Civil Engineering 2588-297X 49 1 2017 05 22 Comparative study of carbonate and quartz sand based on energy concepts Comparative study of carbonate and quartz sand based on energy concepts 89 100 592 10.22060/ceej.2016.592 FA M. R. Rasouli Faculty of Engineering, Imam Khomeini International University, Qazvin, Iran M. Hassanlourad Faculty of Civil Engineering, University of Tehran, Tehran, Iran Journal Article 2013 10 14 Abstract: carbonate sands have being known as problematic soils in civil engineering and their strength is different from those of quartz sands. In this paper Triaxial consolidated-drained shear strength of a carbonate sand obtained from north beach of Oman sea is compared with Firoozkooh quartz sand. Energy concept is used for the analysis. Tests were performed in the same conditions such as particle size distribution, relative density and confining pressure on sands with different particles shapes. Tests results and analysis showed considerable differences between two sands regarding the shear strength and its components, soil volume changes, particle breakage potential and its effects on the shear strength, consumed energy for the particle crushing, dilation and particle crushing portion from the total internal friction angle of soils. At the end, it was found that there is a linear relation between the consumed energy for particle crushing from total applied energy to the soil speciment and particle breakage portion from the soil total internal friction angle. In the carbonate sand with high particle breakage ability a value of %14 to %31 and in the quartz sand maximum %10 of applied energy is consumed for particle breakage. Abstract: carbonate sands have being known as problematic soils in civil engineering and their strength is different from those of quartz sands. In this paper Triaxial consolidated-drained shear strength of a carbonate sand obtained from north beach of Oman sea is compared with Firoozkooh quartz sand. Energy concept is used for the analysis. Tests were performed in the same conditions such as particle size distribution, relative density and confining pressure on sands with different particles shapes. Tests results and analysis showed considerable differences between two sands regarding the shear strength and its components, soil volume changes, particle breakage potential and its effects on the shear strength, consumed energy for the particle crushing, dilation and particle crushing portion from the total internal friction angle of soils. At the end, it was found that there is a linear relation between the consumed energy for particle crushing from total applied energy to the soil speciment and particle breakage portion from the soil total internal friction angle. In the carbonate sand with high particle breakage ability a value of %14 to %31 and in the quartz sand maximum %10 of applied energy is consumed for particle breakage. https://ceej.aut.ac.ir/article_592_dbe272bab69f8e13f14b405e038deb64.pdf

Amirkabir University of Technology Amirkabir Journal of Civil Engineering 2588-297X 49 1 2017 05 22 Study of Effects of Type and Amount of Steel Fibers and Diameter of Projectile on Behavior of UHPSFRC Study of Effects of Type and Amount of Steel Fibers and Diameter of Projectile on Behavior of UHPSFRC 101 118 865 10.22060/ceej.2016.865 FA G. Dehghani Ashkezari Passive Defense Department, Malek Ashtar University of Technology, Tehran, Iran Journal Article 2013 08 14 In this study, firstly the impact behavior of a kind of ultra-high performance steel fiber reinforced concrete (UHPSFRC) with one and two percent steel fiber by concrete volume are investigated under drop-weight test by using of constraint and simple supports condition. The results of tests show that fiber content has a significant effect on impact behavior of UHPFRCs, so that by increase of fiber content from one percent to two percent, the numbers of drops required to final failure of concrete targets are becoming nearly two times. Then, impact and penetration of high velocity projectile on UHPSFRC targets has been simulated by using of LS-DYNA software based on erosion algorithm. In this study, Elastic-Plastic Hydrodynamic material model has been used to modeling the behavior of concrete. This material model is able to consider the softening behavior of material due to post-yield damage by getting tabulated effective stress and effective plastic strain. Comparison between numerical and experimental results shows that the hydrodynamic model is able to describe the responses of UHPSFRC under impact loading. Besides, by adding of more fibers, concrete targets can obtain greater toughness due to higher residual strength and greater strains. It leads to reduce the penetration depth and the diameter of the cavity that are created in target due to impact of the projectile and spread of stress waves. In this study, firstly the impact behavior of a kind of ultra-high performance steel fiber reinforced concrete (UHPSFRC) with one and two percent steel fiber by concrete volume are investigated under drop-weight test by using of constraint and simple supports condition. The results of tests show that fiber content has a significant effect on impact behavior of UHPFRCs, so that by increase of fiber content from one percent to two percent, the numbers of drops required to final failure of concrete targets are becoming nearly two times. Then, impact and penetration of high velocity projectile on UHPSFRC targets has been simulated by using of LS-DYNA software based on erosion algorithm. In this study, Elastic-Plastic Hydrodynamic material model has been used to modeling the behavior of concrete. This material model is able to consider the softening behavior of material due to post-yield damage by getting tabulated effective stress and effective plastic strain. Comparison between numerical and experimental results shows that the hydrodynamic model is able to describe the responses of UHPSFRC under impact loading. Besides, by adding of more fibers, concrete targets can obtain greater toughness due to higher residual strength and greater strains. It leads to reduce the penetration depth and the diameter of the cavity that are created in target due to impact of the projectile and spread of stress waves. https://ceej.aut.ac.ir/article_865_3b3dbaf68507998acd6a5a5254ab2d76.pdf

Amirkabir University of Technology Amirkabir Journal of Civil Engineering 2588-297X 49 1 2017 05 22 Multi Degree of Freedom Effects on Ductility Reduction Factor for Near Fault Ground Motions Multi Degree of Freedom Effects on Ductility Reduction Factor for Near Fault Ground Motions 119 126 690 10.22060/ceej.2016.690 FA S. B. Beheshti‑Aval Faculty of Civil Engineering, KNTU University of Technology, Tehran, Iran Sh. Kabiri Faculty of Civil Engineering, KNTU University of Technology, Tehran, Iran Journal Article 2011 12 03 Study on single degree of freedom (SDOF) structures provided information on seismic demand for elastic and inelastic systems. But this information needs to be modified to become of direct use for design of real structures, which are mostly multi-degree of freedom (MDOF) systems, governed by several modes. According to the near fault ground motions have cause much damage in the vicinity of seismic sources, this paper evaluate the modification that must applied to strength reduction factors derived from simplified SDOF models in order to account for MDOF structures in near fault zones. This proposed by estimation the ratio of strength in MDOF systems that result by limiting maximum story ductility ratio to the strength corresponding to the same ground motion and same level of ductility in an equivalent SDOF system having a period equal to the fundamental period of the MDOF structures.Nonlinear dynamic time history analysis were carried out on four steel moment resisting frames with two distinct behavior of yield mechanism, undergoing five level of ductility ratio when subjected to 15 near fault ground motions with forward directivity effects. Modification factors spectra were computed as a function of period and number of stories and were compared to those of corresponding spectra for far fault ground motions. The required modification factor for inelastic MDOF systems, for near fault motions was shown to be dependent on target ductility ratio and the type of yield mechanism and to a lesser degree, period of vibration and number of stories. The result demonstrate that in the low level of ductility ratio, during the short period range, the modification factor given from near the fault ground motions is less than those from the far fault ground motions, and this is true during all period range as the level of ductility is increased. Finally, since the equivalent pulse of near fault ground motions have<br />significant effect on structural response, modification factors were proposed as a function of the ratio of structural period to equivalent pulse period and ductility ratios. Study on single degree of freedom (SDOF) structures provided information on seismic demand for elastic and inelastic systems. But this information needs to be modified to become of direct use for design of real structures, which are mostly multi-degree of freedom (MDOF) systems, governed by several modes. According to the near fault ground motions have cause much damage in the vicinity of seismic sources, this paper evaluate the modification that must applied to strength reduction factors derived from simplified SDOF models in order to account for MDOF structures in near fault zones. This proposed by estimation the ratio of strength in MDOF systems that result by limiting maximum story ductility ratio to the strength corresponding to the same ground motion and same level of ductility in an equivalent SDOF system having a period equal to the fundamental period of the MDOF structures.Nonlinear dynamic time history analysis were carried out on four steel moment resisting frames with two distinct behavior of yield mechanism, undergoing five level of ductility ratio when subjected to 15 near fault ground motions with forward directivity effects. Modification factors spectra were computed as a function of period and number of stories and were compared to those of corresponding spectra for far fault ground motions. The required modification factor for inelastic MDOF systems, for near fault motions was shown to be dependent on target ductility ratio and the type of yield mechanism and to a lesser degree, period of vibration and number of stories. The result demonstrate that in the low level of ductility ratio, during the short period range, the modification factor given from near the fault ground motions is less than those from the far fault ground motions, and this is true during all period range as the level of ductility is increased. Finally, since the equivalent pulse of near fault ground motions have<br />significant effect on structural response, modification factors were proposed as a function of the ratio of structural period to equivalent pulse period and ductility ratios. https://ceej.aut.ac.ir/article_690_c06d06da9666a219db15cf575aff2824.pdf

Amirkabir University of Technology Amirkabir Journal of Civil Engineering 2588-297X 49 1 2017 05 22 A 3-stage Method for Selection of Ground Motion for Dynamic Time History Analysis A 3-stage Method for Selection of Ground Motion for Dynamic Time History Analysis 127 138 603 10.22060/ceej.2016.603 FA F. Behnamfar Department of Civil Engineering, Isfahan University of Technology, Esfahan, Iran 0000-0002-9365-8295 M. Nooraei Senior Earthquake Engineer, Consultant Engineers, Esfahan, Iran M. Talebi Senior Structural Engineer, Consultant Engineers, Chaloos, Iran Journal Article 2013 12 14 Results of any dynamic analysis are clearly influenced by the type of the selected acceleration records as the use of inappropriate records can lead to a misunderstanding of the real behavior of structures against earthquakes. <br />For compatibility of accelerograms various criteria including similarity of focal mechanism and magnitude, the same distance from the epicenter, and finally the same soil type of recording stations has been mentioned. Even with respect to these criteria, referencing to databases of earthquakes results in finding several hundreds and sometimes several thousands of apparently suitable accelerograms. Additional measures should be considered to minimize the number of appropriate records. <br />In this paper a three-step screening process is presented during which the number of selected records is quickly reduced from a few thousands to a few number. The finally selected records are the most appropriate for the studied structure regarding the chosen requirements. <br />In the first stage, called the coarse sieve, ground motion parameters and geological parameters are used to select the records. In the second stage, known as the intermediate sieve, a suit of earthquake records that are more similar in terms of spectral parameters are extracted and in the third and last stage, known as the fine sieve, the final records are selected with studying the spectral shapes of the records. It is shown that the proposed selection method results in a much less scatter in the nonlinear structural responses among the selected earthquakes resulting in an enhanced confidence in the safety of the designed structure. Results of any dynamic analysis are clearly influenced by the type of the selected acceleration records as the use of inappropriate records can lead to a misunderstanding of the real behavior of structures against earthquakes. <br />For compatibility of accelerograms various criteria including similarity of focal mechanism and magnitude, the same distance from the epicenter, and finally the same soil type of recording stations has been mentioned. Even with respect to these criteria, referencing to databases of earthquakes results in finding several hundreds and sometimes several thousands of apparently suitable accelerograms. Additional measures should be considered to minimize the number of appropriate records. <br />In this paper a three-step screening process is presented during which the number of selected records is quickly reduced from a few thousands to a few number. The finally selected records are the most appropriate for the studied structure regarding the chosen requirements. <br />In the first stage, called the coarse sieve, ground motion parameters and geological parameters are used to select the records. In the second stage, known as the intermediate sieve, a suit of earthquake records that are more similar in terms of spectral parameters are extracted and in the third and last stage, known as the fine sieve, the final records are selected with studying the spectral shapes of the records. It is shown that the proposed selection method results in a much less scatter in the nonlinear structural responses among the selected earthquakes resulting in an enhanced confidence in the safety of the designed structure. https://ceej.aut.ac.ir/article_603_d86ea612dec96096c5e0fcc8dd42ab6d.pdf

Amirkabir University of Technology Amirkabir Journal of Civil Engineering 2588-297X 49 1 2017 05 22 Treatment of High Polluted Leachate By Subsurface Flow Constructed Wetland With Vetiver Treatment of High Polluted Leachate By Subsurface Flow Constructed Wetland With Vetiver 139 148 496 10.22060/ceej.2015.496 FA R. Bakhshoodeh 1 Department of Environmental Engineering, Faculty of Water Sciences Engineering, Shahid Chamran University of Ahvaz, Ahvaz, Iran A. Soltani-Mohammadi Irrigation and Drainage Department, Faculty of Water Sciences Engineering, Shahid Chamran University of Ahvaz, Ahvaz, Iran N. Alavi Department of Environmental Health Engineering, School of Public Health, Shahid Beheshti University of Medical Sciences, Tehran, Iran 4 H. Ghanavati Microbial Biotechnology Department, Agricultural Biotechnology Research Institute of Iran (ABRII), Karaj, Iran Journal Article 2014 01 29 Landfill leachate usually contains high concentrations of pollutions that are seriously harmful to the environment and human health. The main purpose of this study was removing organic pollution, ammonia, nitrate and total nitrogen in Isfahan composting facility leachate by horizontal constructed wetland systems. A pilot-scale study was conducted on subsurface flow constructed wetland systems operated in horizontal mode (HFCWs).Two horizontal systems with different plants were constructed, one planted with Vetiver and the other one without plant as a control. They were operated identically at a flow rate of 27 l/day with a 5 day hydraulic retention time. The average removal efficiencies for control and experiment were BOD₅, 9% and 30%; COD, 19 and 34%; TN, 37 and 50%; Ammonium, 8 and 26%; nitrate 33 and 40% respectively. Due to high concentration of pollutants (the mean leachate concentrations of COD, BOD₅, TSS, NH₄⁺-N, NO₃^- -N, TN were 104514.9, 69200.0, 8478.3, 317.5, 4633.2 and 1500 mg/L, respectively) the subsurface flow constructed wetland systems with Vetiver plant is a suitable solution for leachate treatment. Landfill leachate usually contains high concentrations of pollutions that are seriously harmful to the environment and human health. The main purpose of this study was removing organic pollution, ammonia, nitrate and total nitrogen in Isfahan composting facility leachate by horizontal constructed wetland systems. A pilot-scale study was conducted on subsurface flow constructed wetland systems operated in horizontal mode (HFCWs).Two horizontal systems with different plants were constructed, one planted with Vetiver and the other one without plant as a control. They were operated identically at a flow rate of 27 l/day with a 5 day hydraulic retention time. The average removal efficiencies for control and experiment were BOD₅, 9% and 30%; COD, 19 and 34%; TN, 37 and 50%; Ammonium, 8 and 26%; nitrate 33 and 40% respectively. Due to high concentration of pollutants (the mean leachate concentrations of COD, BOD₅, TSS, NH₄⁺-N, NO₃^- -N, TN were 104514.9, 69200.0, 8478.3, 317.5, 4633.2 and 1500 mg/L, respectively) the subsurface flow constructed wetland systems with Vetiver plant is a suitable solution for leachate treatment. https://ceej.aut.ac.ir/article_496_b534ba68236ba543ae44b22bd110a1d6.pdf

Amirkabir University of Technology Amirkabir Journal of Civil Engineering 2588-297X 49 1 2017 05 22 Seismic Analysis of Rectangular Tunnels (Cut and Cover Method), Soil- Structure Interaction Seismic Analysis of Rectangular Tunnels (Cut and Cover Method), Soil- Structure Interaction 149 164 420 10.22060/ceej.2015.420 FA A. Lakirouhani Department of Civil Engineering, Faculty of Engineering, University of Zanjan, Zanjan, Iran 0000-0001-5449-8420 Sh. Alioskooyi Department of Civil Engineering, Faculty of Engineering, University of Zanjan, Zanjan, Iran Journal Article 2014 01 28 One of tunneling methods is cut and cover method, in which the excavation start from the ground surface and deep in the ground, then a concrete box is made as a tunnel. Thus in this method, the cross section of the tunnel is not circular but rectangular. The aim of this paper is seismic analysis of rectangular tunnels. For a special accelerogram, tunnel geometry, depth of overburden and ground conditions, are the three main factors affecting the dynamic behavior of the tunnels. By numerical methods, and by assuming the plane strain condition, models of this type of tunnels were analyzed. According to the results, the maximum internal forces that are generated in the tunnel lining and the stress concentration are at the corners of the cross section of rectangular tunnel. In seismic mode, the internal forces of concrete lining are several times of static mode. In this situation, the ground surface settlement profiles are asymmetric and the settlement is greater than the static mode. In tunnels with large width, in 2D cases, if a column be placed in the middle of span, the ground settlement, bending moment and shear forces is decreased in comparison with 1 span tunnel with the same dimension One of tunneling methods is cut and cover method, in which the excavation start from the ground surface and deep in the ground, then a concrete box is made as a tunnel. Thus in this method, the cross section of the tunnel is not circular but rectangular. The aim of this paper is seismic analysis of rectangular tunnels. For a special accelerogram, tunnel geometry, depth of overburden and ground conditions, are the three main factors affecting the dynamic behavior of the tunnels. By numerical methods, and by assuming the plane strain condition, models of this type of tunnels were analyzed. According to the results, the maximum internal forces that are generated in the tunnel lining and the stress concentration are at the corners of the cross section of rectangular tunnel. In seismic mode, the internal forces of concrete lining are several times of static mode. In this situation, the ground surface settlement profiles are asymmetric and the settlement is greater than the static mode. In tunnels with large width, in 2D cases, if a column be placed in the middle of span, the ground settlement, bending moment and shear forces is decreased in comparison with 1 span tunnel with the same dimension https://ceej.aut.ac.ir/article_420_b6f0479ae87d244975439c6124592772.pdf

Amirkabir University of Technology Amirkabir Journal of Civil Engineering 2588-297X 49 1 2017 05 22 calculation of Functional Costs Reduction in Economic Evaluation of Roads Rehalibitation(Case Study: Fasa-Zahedshahr Main Road) calculation of Functional Costs Reduction in Economic Evaluation of Roads Rehalibitation(Case Study: Fasa-Zahedshahr Main Road) 165 174 573 10.22060/ceej.2016.573 FA A. Mansourkhaki Department of Road and Transportation Engineering, Iran University of Science and Technology, Tehran, Iran S. R. Moosavi Department of Road and Transportation Engineering, Iran University of Science and Technology, Tehran, Iran 0000-0002-8904-6456 A. Rezaee-Arjrodi Transportation Research Institute, Housing and Urban Way Research Center, Tehran, Iran Journal Article 2013 09 16 In this study, to prevent pavement destruction and enhance the quality level, restoration and improvement of roads are carried out. The operational costs include fuel consumption, travel time, accidents, tires’ wear and tear and so on. In the economic evaluation, reduction of such costs due to the improvement of the quality level of roads is considered as the project’s benefits. In this paper, the benefits gained through roads’ improvement (i.e. costs reduction) are compared with another one and then the priority of each one in the economic evaluation is determined using the results found from the B/C and Net Present Value (NPV) methods. For this purpose, the required model has been prepared using software written with the Visual Basic Programming Language and its output has been presented as the results of a case study carried out in Fasa-Zahedshahr main road. The evaluation of each element in the economic viability of roads’ improvement projects is one of the specific features of the model presented in this paper. In this study, to prevent pavement destruction and enhance the quality level, restoration and improvement of roads are carried out. The operational costs include fuel consumption, travel time, accidents, tires’ wear and tear and so on. In the economic evaluation, reduction of such costs due to the improvement of the quality level of roads is considered as the project’s benefits. In this paper, the benefits gained through roads’ improvement (i.e. costs reduction) are compared with another one and then the priority of each one in the economic evaluation is determined using the results found from the B/C and Net Present Value (NPV) methods. For this purpose, the required model has been prepared using software written with the Visual Basic Programming Language and its output has been presented as the results of a case study carried out in Fasa-Zahedshahr main road. The evaluation of each element in the economic viability of roads’ improvement projects is one of the specific features of the model presented in this paper. https://ceej.aut.ac.ir/article_573_e5f6ad6ce374177eef023bf5d0c018b6.pdf

Amirkabir University of Technology Amirkabir Journal of Civil Engineering 2588-297X 49 1 2017 05 22 Effects of Connector pattern on Traffic Assignment Results;Case Study: Qazvin Effects of Connector pattern on Traffic Assignment Results;Case Study: Qazvin 175 184 702 10.22060/ceej.2016.702 FA M. Bashirinia Civil and Environmental Engineering, Tarbiat Modares University, Tehran, Iran A. R. Mamdoohi Civil and Environmental Engineering, Tarbiat Modares University, Tehran, Iran 0000-0002-5339-9807 Journal Article 2014 03 03 In Transportation Literature, in order to relate supply (street network) and demand (Traffic Zone) definition of centroid and its connector(s) is essential. Centroid and its connector(s) selection, despite its importance, are usually done based on the general knowledge of researcher from network, his/her judgment and experiment. The main purpose of this paper is to investigate the effect of centroid connection pattern on static traffic assignment. Using User Equilibrium approach, different scenarios of connections from one connector to all the possible connectors got evaluated. This issue is investigated in Qazvin network which has 113 traffic zones and approximately 400 thousands inhabitants. Applying 6 different scenarios showed that amending in pattern and number of connectors would result 10 percent change in average link volumes and about 20 percent change in total vehicle-kilometer of network. As a result of connection pattern and assessor multiplicity, it is difficult to specify the optimum pattern; this difficulty indicates the effects of connector pattern on traffic assignment results. In Transportation Literature, in order to relate supply (street network) and demand (Traffic Zone) definition of centroid and its connector(s) is essential. Centroid and its connector(s) selection, despite its importance, are usually done based on the general knowledge of researcher from network, his/her judgment and experiment. The main purpose of this paper is to investigate the effect of centroid connection pattern on static traffic assignment. Using User Equilibrium approach, different scenarios of connections from one connector to all the possible connectors got evaluated. This issue is investigated in Qazvin network which has 113 traffic zones and approximately 400 thousands inhabitants. Applying 6 different scenarios showed that amending in pattern and number of connectors would result 10 percent change in average link volumes and about 20 percent change in total vehicle-kilometer of network. As a result of connection pattern and assessor multiplicity, it is difficult to specify the optimum pattern; this difficulty indicates the effects of connector pattern on traffic assignment results. https://ceej.aut.ac.ir/article_702_b1eec33c726a60554bc78518d5f9b32c.pdf

Amirkabir University of Technology Amirkabir Journal of Civil Engineering 2588-297X 49 1 2017 05 22 Developing a Model For Forecasting the Success of Construction Projects Integration Taguchi Design (DOE) And TAXONOMY Developing a Model For Forecasting the Success of Construction Projects Integration Taguchi Design (DOE) And TAXONOMY 185 196 703 10.22060/ceej.2016.703 FA S. M. Zanjirchi Economic, Accounting & Management Faculty, Yazd University, Yazd, Iran F. Aziz Management & Accounting Faculty, Allameh Tabatabaee University, Tehran, Iran M. Amani Management Faculty, Tehran University, Tehran, Iran Journal Article 2014 07 18 The construction industry is the largest industry in the world. It is more of a service than a manufacturing industry. The success of construction projects is a fundamental issue for most governments, users and communities. Multi Criteria Decision Making is an approach that can be used to deal complex problems. In this paper, to treat multi criteria decision making problems in uncertain condition a model based on grey theory-including grey relational analysis and grey numbers is proposed. The scope of research about gray theory and multiple criteria decision making is relatively new field, so in this study we used the integration of Taguchi and Taxonomy with gray theory to forecasting the success of construction projects. Using Taguchi method and gray theory, weight of each criterion was determined. Finally, using Taxonomy and gray theory the success of thirteen construction projects was forecasted. Findings of this study provide clear understanding of constuction project and could potentially enhance existing knowledge of construction project success. The construction industry is the largest industry in the world. It is more of a service than a manufacturing industry. The success of construction projects is a fundamental issue for most governments, users and communities. Multi Criteria Decision Making is an approach that can be used to deal complex problems. In this paper, to treat multi criteria decision making problems in uncertain condition a model based on grey theory-including grey relational analysis and grey numbers is proposed. The scope of research about gray theory and multiple criteria decision making is relatively new field, so in this study we used the integration of Taguchi and Taxonomy with gray theory to forecasting the success of construction projects. Using Taguchi method and gray theory, weight of each criterion was determined. Finally, using Taxonomy and gray theory the success of thirteen construction projects was forecasted. Findings of this study provide clear understanding of constuction project and could potentially enhance existing knowledge of construction project success. https://ceej.aut.ac.ir/article_703_d6c651ddcd97183b2e40bc464231c962.pdf

Amirkabir University of Technology Amirkabir Journal of Civil Engineering 2588-297X 49 1 2017 05 22 consequences of the Recently Modification of Iran Seismic Design Code (No. 2800) (Due to A*B) and Proposing Forward Directivity Effect Coefficients (Na and Nv) consequences of the Recently Modification of Iran Seismic Design Code (No. 2800) (Due to A*B) and Proposing Forward Directivity Effect Coefficients (Na and Nv) 197 208 1045 10.22060/ceej.2017.11931.5101 FA A. Nicknam Iran University of Science and Technology, Tehran, Iran Journal Article 2016 08 30 This article intends to criticize and discuss the challenging of the design spectra in Iran seismic design (No. 2800, 4th version) mainly due to its two parametric form (A×B) and highlight its weaknesses regarding the current earthquake engineering principals. Examples of the discussed points include the predefined spectral shape as a fixed envelope of spectral ordinates at the constant maximum acceleration and velocity ranges, the dependency of corner period (Ts) to those of constant spectral acceleration, meaningless of the defined parameter (S) in spectral shape formula. The design spectral acceleration in the third and fourth 2800’s code are compared and assessed. A simple methodology for assessing the existing period dependent forward directivity effects parameter, N(T) is presented. The real spectral ordinates data at 120 near source sites from the two cities in the United State on four site soil types are used to develop the presented two parameters as representatives of FD-pulse effects; Na(T1) (for the constant maximum spectral ordinate range of period) and Nv(T) (for constant maximum velocity spectral ordinate range of period). The average values of the obtained design spectra are compared with those of the 2800’s third and fourth versions and the differences are the results are assessed. The resulted considerable differences confirm the necessary modification of the currently used design response spectra in the both period ranges of; the constant maximum acceleration spectra and acceleration spectra at the constant maximum velocity. This article intends to criticize and discuss the challenging of the design spectra in Iran seismic design (No. 2800, 4th version) mainly due to its two parametric form (A×B) and highlight its weaknesses regarding the current earthquake engineering principals. Examples of the discussed points include the predefined spectral shape as a fixed envelope of spectral ordinates at the constant maximum acceleration and velocity ranges, the dependency of corner period (Ts) to those of constant spectral acceleration, meaningless of the defined parameter (S) in spectral shape formula. The design spectral acceleration in the third and fourth 2800’s code are compared and assessed. A simple methodology for assessing the existing period dependent forward directivity effects parameter, N(T) is presented. The real spectral ordinates data at 120 near source sites from the two cities in the United State on four site soil types are used to develop the presented two parameters as representatives of FD-pulse effects; Na(T1) (for the constant maximum spectral ordinate range of period) and Nv(T) (for constant maximum velocity spectral ordinate range of period). The average values of the obtained design spectra are compared with those of the 2800’s third and fourth versions and the differences are the results are assessed. The resulted considerable differences confirm the necessary modification of the currently used design response spectra in the both period ranges of; the constant maximum acceleration spectra and acceleration spectra at the constant maximum velocity. https://ceej.aut.ac.ir/article_1045_a0e2a2c563d57df27213ede1ac4ac780.pdf