Amirkabir University of TechnologyAmirkabir Journal of Civil Engineering2588-297X42320140121The Effect of FRP Strengthening of Boundary Elements in Slender RC Shear WallThe Effect of FRP Strengthening of Boundary Elements in Slender RC Shear Wall1818910.22060/ceej.2014.189FADavodMostofinejadMaryamMohammadi AnaeiJournal Article20140316Concrete shear walls are the most common system resisting against seismic loads in the world. These elements carry the lateral loads by a combination of the axial, shear and flexural responses. Change in the seismic code requirements, subjecting intensive dynamic loads such as explosion or earthquake and other destructive effects make the shear walls weak for continuing service life. In the recent years FRP materials have attracted much interest. FRP application in retrofitting projects is appealing because of their unique properties. Nevertheless, a review on the previous studies shows that despite the squat walls, very limited analytical and/or experimental studies have been conducted on the FRP strengthening of the slender RC shear walls under monotonic loading so far. In this paper it is focused on the strengthening of boundary elements with FRP and it’s effect on the wall behavior. The finite element software is calibrated and verified using available experimental data. Nonlinear finite element analysis of reinforced concrete walls is performed using damage plasticity model and tension stiffening effects. Results of the current study show the superior effectiveness of strengthening FRP composite layers on the behavior of the concrete shear walls.Concrete shear walls are the most common system resisting against seismic loads in the world. These elements carry the lateral loads by a combination of the axial, shear and flexural responses. Change in the seismic code requirements, subjecting intensive dynamic loads such as explosion or earthquake and other destructive effects make the shear walls weak for continuing service life. In the recent years FRP materials have attracted much interest. FRP application in retrofitting projects is appealing because of their unique properties. Nevertheless, a review on the previous studies shows that despite the squat walls, very limited analytical and/or experimental studies have been conducted on the FRP strengthening of the slender RC shear walls under monotonic loading so far. In this paper it is focused on the strengthening of boundary elements with FRP and it’s effect on the wall behavior. The finite element software is calibrated and verified using available experimental data. Nonlinear finite element analysis of reinforced concrete walls is performed using damage plasticity model and tension stiffening effects. Results of the current study show the superior effectiveness of strengthening FRP composite layers on the behavior of the concrete shear walls.Amirkabir University of TechnologyAmirkabir Journal of Civil Engineering2588-297X42320140121Fluid Flow Modeling in Single Fracture Using Cellular Automata MethodFluid Flow Modeling in Single Fracture Using Cellular Automata Method91819010.22060/ceej.2014.190FAAliVaresvazirianAhmadFahimifarJournal Article20140316Fluid flow simulation through a natural fracture is one of the most important and complex problem in Geomechanics. In general, various analytical and numerical methods are used to model fluid flow in fractures. Cellular automata method has been known as a powerful tool for simulation of complex phenomena such as fluid flow, fault movement and fracture production and propagation in a media. As a result, it can have predominant role on simulation of fluid flow in rock fractures. <br />In this study, the modeling of fluid flow in ideal fracture has been carried out employing cellular automata method. For this purpose, a computer program has been developed and used in Fortran Power Station Domain. In this paper, the cellular automata method has been introduced and its application in fluid flow modeling described. The method of fluid flow simulation has also been presented and the results compared with available analytical solution. Fluid flow simulation through a natural fracture is one of the most important and complex problem in Geomechanics. In general, various analytical and numerical methods are used to model fluid flow in fractures. Cellular automata method has been known as a powerful tool for simulation of complex phenomena such as fluid flow, fault movement and fracture production and propagation in a media. As a result, it can have predominant role on simulation of fluid flow in rock fractures. <br />In this study, the modeling of fluid flow in ideal fracture has been carried out employing cellular automata method. For this purpose, a computer program has been developed and used in Fortran Power Station Domain. In this paper, the cellular automata method has been introduced and its application in fluid flow modeling described. The method of fluid flow simulation has also been presented and the results compared with available analytical solution. Amirkabir University of TechnologyAmirkabir Journal of Civil Engineering2588-297X42320140121An Investigation of Local Site Effects on Strong Ground Motions in Abbas-Abad (Tehran Mosalla) RegionAn Investigation of Local Site Effects on Strong Ground Motions in Abbas-Abad (Tehran Mosalla) Region192819110.22060/ceej.2014.191FASeyed MajddinMirhoseiniSeyyed MahdiBabaeeJournal Article20140316Local site effects play a very important role in characterizing seismic and design ground motions because they may strongly amplify (or deamplify) seismic motions before reaching the ground surface. <br />The purpose of this paper is to evaluate local ground response in ABASBAD region (around the TEHRAN MOSALLA). To perform dynamic analysis, soil layers dynamic characteristics is determined from seismic down-hole tests performed at 6 borehole stations. Bedrock Seismicity characteristics is evaluated and 15 accelerograms from various earthquakes around the world is selected. Considering the local topography and soil conditions, one dimensional equivalent linear analysis is performed and results is presented in form of microzonation maps of maximum ground acceleration and velocity, maximum amplification and site specific design spectra. The results indicate that presence of stiff shallow granular soil layers has no considerable affect on bedrock seismic motions and using Iranian earthquake code (2800) normalized design spectra for this site, is conservative at long periods.Local site effects play a very important role in characterizing seismic and design ground motions because they may strongly amplify (or deamplify) seismic motions before reaching the ground surface. <br />The purpose of this paper is to evaluate local ground response in ABASBAD region (around the TEHRAN MOSALLA). To perform dynamic analysis, soil layers dynamic characteristics is determined from seismic down-hole tests performed at 6 borehole stations. Bedrock Seismicity characteristics is evaluated and 15 accelerograms from various earthquakes around the world is selected. Considering the local topography and soil conditions, one dimensional equivalent linear analysis is performed and results is presented in form of microzonation maps of maximum ground acceleration and velocity, maximum amplification and site specific design spectra. The results indicate that presence of stiff shallow granular soil layers has no considerable affect on bedrock seismic motions and using Iranian earthquake code (2800) normalized design spectra for this site, is conservative at long periods.Amirkabir University of TechnologyAmirkabir Journal of Civil Engineering2588-297X42320140121Geo-environmental Behaviour of Nanoclays in Interaction with Heavy Metal ContaminantsGeo-environmental Behaviour of Nanoclays in Interaction with Heavy Metal Contaminants293619210.22060/ceej.2014.192FAVahid RezaOuhadiMohammadAmiri0000-0002-3751-0261Journal Article20140316In recent years, the use of nanoclays in different projects are reported. However, there has been very little attention on the application of nanoclays in geo-environmental projects. In this paper the possibility of application of nanoclays for retention of heavy metal (HM) contaminant were investigated. To achieve this objective a series of experiments were performed on bentonite, kaolinite and nanoclays samples. The buffering capacity, retention properties and XRD experiments show that among Cation Exchange Capacity (CEC), specific surface area, and carbonate, the main factor that controls the soil-HM interaction is carbonate phase. The CEC is the second important factor. Furthermore, after interaction of soil samples with HM the intensity of basal spacing of minerals in XRD decreased. In Cloisite 15A which had the minimum interaction with HM, the minimum reduction in peak intensity was observed (200 Cps). In addition, the contaminant retention of soil samples are in accordance to following order: <br /> Bentonite> Cloisite®Na<sup>+</sup> > Kaolinite> Cloisite®30B > Cloisite®20A > Cloisite®15AIn recent years, the use of nanoclays in different projects are reported. However, there has been very little attention on the application of nanoclays in geo-environmental projects. In this paper the possibility of application of nanoclays for retention of heavy metal (HM) contaminant were investigated. To achieve this objective a series of experiments were performed on bentonite, kaolinite and nanoclays samples. The buffering capacity, retention properties and XRD experiments show that among Cation Exchange Capacity (CEC), specific surface area, and carbonate, the main factor that controls the soil-HM interaction is carbonate phase. The CEC is the second important factor. Furthermore, after interaction of soil samples with HM the intensity of basal spacing of minerals in XRD decreased. In Cloisite 15A which had the minimum interaction with HM, the minimum reduction in peak intensity was observed (200 Cps). In addition, the contaminant retention of soil samples are in accordance to following order: <br /> Bentonite> Cloisite®Na<sup>+</sup> > Kaolinite> Cloisite®30B > Cloisite®20A > Cloisite®15AAmirkabir University of TechnologyAmirkabir Journal of Civil Engineering2588-297X42320140121Investigation of New Seismic Rules of Steel Structures in Performance Base DesignInvestigation of New Seismic Rules of Steel Structures in Performance Base Design374419410.22060/ceej.2014.194FAMohsenTehranizadehNasrinBakhshayeshJournal Article20140316In this paper, seismic performance of steel moment frames is investigated. Linear static and nonlinear static and dynamic of time history analysis have been performed on the usual and special steel moment resistant of 5, 10, 15 stories frames according to third addition of 2800 certification and new seismic rules and the performance of the members have bring under consideration. In the time history analysis, scaled seismographs of Northridge, Lomaprieta and Imperial valley earthquakes are used. At the end, special moment frames that were designed according to new seismic rules, have been designed on performance, has placed on limitation of certification goals.In this paper, seismic performance of steel moment frames is investigated. Linear static and nonlinear static and dynamic of time history analysis have been performed on the usual and special steel moment resistant of 5, 10, 15 stories frames according to third addition of 2800 certification and new seismic rules and the performance of the members have bring under consideration. In the time history analysis, scaled seismographs of Northridge, Lomaprieta and Imperial valley earthquakes are used. At the end, special moment frames that were designed according to new seismic rules, have been designed on performance, has placed on limitation of certification goals.Amirkabir University of TechnologyAmirkabir Journal of Civil Engineering2588-297X42320140121Natural Pozzolans Role in Permeability Reduction and Promoting the Concrete Durability Against Chloride AttackNatural Pozzolans Role in Permeability Reduction and Promoting the Concrete Durability Against Chloride Attack455319710.22060/ceej.2014.197FAAliakbarRamezanianpourMansourPeydaayeshSeyedMirvaladEhsanAramoonJournal Article20140316This paper presents the results of experimental study on the effect of natural pozzolans: Jajrood Truss, Eskandan Pumice, Abyek Tuff, and Khash Pumice, on the ordinary structural concrete durability in chloride corrosion. Concrete specimens were made of three pozzolan replacements, and Rapid Chloride Penetration test, Electrical Resistance test, Half-Cell Potential test, water permeability test, and water adsorption test were conducted in different ages. <br />Generally, the results indicate that natural pozzolans have positive effects on concrete specimen resistance to the chloride ions penetration and bars corrosion in comparison with concretes containing ordinary cement.This paper presents the results of experimental study on the effect of natural pozzolans: Jajrood Truss, Eskandan Pumice, Abyek Tuff, and Khash Pumice, on the ordinary structural concrete durability in chloride corrosion. Concrete specimens were made of three pozzolan replacements, and Rapid Chloride Penetration test, Electrical Resistance test, Half-Cell Potential test, water permeability test, and water adsorption test were conducted in different ages. <br />Generally, the results indicate that natural pozzolans have positive effects on concrete specimen resistance to the chloride ions penetration and bars corrosion in comparison with concretes containing ordinary cement.Amirkabir University of TechnologyAmirkabir Journal of Civil Engineering2588-297X42320140121Dynamic & Static Load Testing of Bridges, Case Study of Qale Morqi Bridge in TehranDynamic & Static Load Testing of Bridges, Case Study of Qale Morqi Bridge in Tehran556419810.22060/ceej.2014.198FAFerydonRezaieSeyed MasoudNasr AzadaniSiyamakRazaghiJournal Article20140316Bridge performance and health monitoring can be obtained from numerical models, site load test or combination of both. Load test approach illustrates bridge behavior with minimum inaccuracy without taking into account the assumptions and simplified approaches of structure analysis. In this research, the structure of Qale Morqi bridge was investigated in order to identify the bridge performance and defects that cause vibration to be induced into surrounding buildings. Numerical models of bridge were made and bridge model was loaded according to bridge Design codes. Bridge was instrumented with more than a hundred sensors, and then loading was implemented in static and dynamic steps. It was observed that the bridge vibrates intensively and instead of bending pattern, the first mode shape was torsional. Due to proximity of bridge first mode with peripheral building first mode, resonance is probable. In conclusion, some strategies for decreasing bridge vibration or preventing resonance in peripheral building arepresented.Bridge performance and health monitoring can be obtained from numerical models, site load test or combination of both. Load test approach illustrates bridge behavior with minimum inaccuracy without taking into account the assumptions and simplified approaches of structure analysis. In this research, the structure of Qale Morqi bridge was investigated in order to identify the bridge performance and defects that cause vibration to be induced into surrounding buildings. Numerical models of bridge were made and bridge model was loaded according to bridge Design codes. Bridge was instrumented with more than a hundred sensors, and then loading was implemented in static and dynamic steps. It was observed that the bridge vibrates intensively and instead of bending pattern, the first mode shape was torsional. Due to proximity of bridge first mode with peripheral building first mode, resonance is probable. In conclusion, some strategies for decreasing bridge vibration or preventing resonance in peripheral building arepresented.Amirkabir University of TechnologyAmirkabir Journal of Civil Engineering2588-297X42320140121Numerical Simulation Scouring in Cohesive Bed around Circular Piers using Finite Volume Solution of Horizontal Turbulent FlowNumerical Simulation Scouring in Cohesive Bed around Circular Piers using Finite Volume Solution of Horizontal Turbulent Flow657220010.22060/ceej.2014.200FASaid RezaSabbagh-YazdiRezaDehghan-NaieriSeyed SaidAshraf-VaghefiJournal Article20140316Numerical solution of depth averaged equations is one of the best ways for describing of two dimensional horizontal flow and behavior of flow around circular piers. In this paper, governing equations of turbulent shallow water flow are converted to discrete form using overlapping finite volume method on triangular unstructured mesh. The equations include to the depth average equation of continuity and motion for flow model and equation for turbulence model. For simulation of scouring in cohesive bed, the results of the flow solver model are combined with the empirical relations obtained from the E-SRICOS bed scouring method which is a laboratory base method for determining rate of flow induced scouring.Numerical solution of depth averaged equations is one of the best ways for describing of two dimensional horizontal flow and behavior of flow around circular piers. In this paper, governing equations of turbulent shallow water flow are converted to discrete form using overlapping finite volume method on triangular unstructured mesh. The equations include to the depth average equation of continuity and motion for flow model and equation for turbulence model. For simulation of scouring in cohesive bed, the results of the flow solver model are combined with the empirical relations obtained from the E-SRICOS bed scouring method which is a laboratory base method for determining rate of flow induced scouring.Amirkabir University of TechnologyAmirkabir Journal of Civil Engineering2588-297X42320140121Statistical assessment of impact resistance of Reactive Powder Concrete and Steel Fiber Reinforced Reactive Powder ConcreteStatistical assessment of impact resistance of Reactive Powder Concrete and Steel Fiber Reinforced Reactive Powder Concrete738320210.22060/ceej.2014.202FAAlirezaBagheriHamedZanganehJournal Article20140316The application of Reactive Powder Concrete for the construction of strategic structures such as shelters is under investigation by many researchers, because of their extremely high compressive strength. In this paper, the impact resistance of Reactive Powder Concrete and Steel Fiber Reinforced Reactive Powder Concrete has been studied by using the repeated drop-weight impact test, recommended by ACI Committee 544. The results have been analyzed using statistical methods. <br />Results show that despite the very high compressive strength of Reactive Powder Concrete; its impact resistance is very low. The impact resistance of Reactive Powder Concrete is substantially increased by application of steel fibers. Kolmogorov–Smirnov test indicated that despite large variability of the results, impact resistance of Reactive Powder Concrete and Steel Fiber Reinforced Reactive Powder Concrete obtained from the repeated drop weight test had the normal distribution.The application of Reactive Powder Concrete for the construction of strategic structures such as shelters is under investigation by many researchers, because of their extremely high compressive strength. In this paper, the impact resistance of Reactive Powder Concrete and Steel Fiber Reinforced Reactive Powder Concrete has been studied by using the repeated drop-weight impact test, recommended by ACI Committee 544. The results have been analyzed using statistical methods. <br />Results show that despite the very high compressive strength of Reactive Powder Concrete; its impact resistance is very low. The impact resistance of Reactive Powder Concrete is substantially increased by application of steel fibers. Kolmogorov–Smirnov test indicated that despite large variability of the results, impact resistance of Reactive Powder Concrete and Steel Fiber Reinforced Reactive Powder Concrete obtained from the repeated drop weight test had the normal distribution.