Semnan University PressJournal of Modeling in Engineering2008-485461520071222Numerical Analysis of Dynamic Behavior of Mechanically Stabilized Earth Walls with GeosyntheticsAn Investigation of Seismic Base-isolators on Stories Displacements and Plastic Hinge FormationNumerical Analysis of Dynamic Behavior of Mechanically Stabilized Earth Walls with GeosyntheticsAn Investigation of Seismic Base-isolators on Stories Displacements and Plastic Hinge Formation151510.22075/jme.2017.1515FAJournal Article20170128  Abstract Earthquake bas-isolation design for structures is based on demand reduction instead of seismic capacity increasing. The effectiveness of two types of seismic base-isolator on base shear and story shear reduction were investigated in this paper. Four structures (2, 5, 8 and 12 story buildings) with different cases including fixed base, laminated rubber bearing (LRB) and frictional pendulum system (FPS) and different isolator stiffness were modeled. The nonlinear time history analysis were performed on all modeled structures subjected to Manjil, Naghan, Tabas and El centro earthquake records. The results show that the LRB increases the maximum story displacement but decreases the story drifts. However, comparison of the results for FPS and fixed base show that the maximum roof displacements for FPS do not increase. Using the seismic isolator decrease the number of displacement response cycles and hinge formation. In general, the seismic isolators are very useful for low-rise structures, specifically for Iranian  Abstract Earthquake bas-isolation design for structures is based on demand reduction instead of seismic capacity increasing. The effectiveness of two types of seismic base-isolator on base shear and story shear reduction were investigated in this paper. Four structures (2, 5, 8 and 12 story buildings) with different cases including fixed base, laminated rubber bearing (LRB) and frictional pendulum system (FPS) and different isolator stiffness were modeled. The nonlinear time history analysis were performed on all modeled structures subjected to Manjil, Naghan, Tabas and El centro earthquake records. The results show that the LRB increases the maximum story displacement but decreases the story drifts. However, comparison of the results for FPS and fixed base show that the maximum roof displacements for FPS do not increase. Using the seismic isolator decrease the number of displacement response cycles and hinge formation. In general, the seismic isolators are very useful for low-rise structures, specifically for Iranianhttps://modelling.semnan.ac.ir/article_1515_2dddfee4efaf3eb057d954e7be36cfcc.pdfSemnan University PressJournal of Modeling in Engineering2008-485461520071222An Investigation of Seismic Base-isolators on Stories Displacements and Plastic Hinge FormationNumerical Analysis of Dynamic Behavior of Mechanically Stabilized Earth Walls with GeosyntheticsAn Investigation of Seismic Base-isolators on Stories Displacements and Plastic Hinge FormationNumerical Analysis of Dynamic Behavior of Mechanically Stabilized Earth Walls with Geosynthetics151610.22075/jme.2017.1516FAJournal Article20170128 Abstract  Nowadays reinforced Mechanically Stabilized Earth Walls (MSEW) with Geosynthetics, are used extensively as retaining walls and bridge abutments in urban and mountainous regions because their advantages. The MSEW is a new branch of construction technology which consists of three elements: compacted backfill, reinforced layers and facing elements. The mechanically stabilized earth Walls have many advantages compared with conventional reinforced concrete and concrete gravity retaining walls such as more flexibility against settlement on soft soils, higher safety during earthquakes and their cost effective. Because of these technical and economical advantages, study of the MSEW behavior in various load conditions like seismic loading is very important. In this paper results from a comprehensive numerical simulation by finite difference method that carried out to investigate the behavior of dynamic response of MSEW are presented. Numerical results illustrate the MSEW dynamic response for fixed toe and sliding toe conditions. Ultimately numerical simulation results show that the stiffness of reinforcement layers are great influence on dynamic load increment in geosynthetics layers. Abstract  Nowadays reinforced Mechanically Stabilized Earth Walls (MSEW) with Geosynthetics, are used extensively as retaining walls and bridge abutments in urban and mountainous regions because their advantages. The MSEW is a new branch of construction technology which consists of three elements: compacted backfill, reinforced layers and facing elements. The mechanically stabilized earth Walls have many advantages compared with conventional reinforced concrete and concrete gravity retaining walls such as more flexibility against settlement on soft soils, higher safety during earthquakes and their cost effective. Because of these technical and economical advantages, study of the MSEW behavior in various load conditions like seismic loading is very important. In this paper results from a comprehensive numerical simulation by finite difference method that carried out to investigate the behavior of dynamic response of MSEW are presented. Numerical results illustrate the MSEW dynamic response for fixed toe and sliding toe conditions. Ultimately numerical simulation results show that the stiffness of reinforcement layers are great influence on dynamic load increment in geosynthetics layers.https://modelling.semnan.ac.ir/article_1516_72be492ba2318f1d25990c4918def37e.pdfSemnan University PressJournal of Modeling in Engineering2008-485461520071222Numerical Study of Using Diamond Metalic Damper for Seismic Retrofit of Medium-rise Steel FramesNumerical Study of Using Diamond Metalic Damper for Seismic Retrofit of Medium-rise Steel Frames151710.22075/jme.2017.1517FAJournal Article20170128 Abstract  Up to now many research projects have been conducted regarding vibration control of structures and reducing seismic demands of main structural members leading to better lateral performance. Passive metallic dampers as fuse elements has attracted many researchers according to their absorbing and damping capacity under severe cyclic loading condition. This lecture analytically investigates effect of adding rhombic metallic dampers on seismic performance of steel frames to be strengthened. Nonlinear time history analysis results of 5 story moment resisting frame showed (53% - 143%) increase in PGA amount that structure can resist and 40% reduction in roof displacement. Using dampers in bracing system in 7 story braced frame caused (54% - 175%) increase in PGA amount that structure can resist, increase in effective equivalent damping to 20% and 72% reduction in base shear. Using the damping strategy, seismic performance of both two type frames got improved from âcollapseâ level to âoperationalâ level. Abstract  Up to now many research projects have been conducted regarding vibration control of structures and reducing seismic demands of main structural members leading to better lateral performance. Passive metallic dampers as fuse elements has attracted many researchers according to their absorbing and damping capacity under severe cyclic loading condition. This lecture analytically investigates effect of adding rhombic metallic dampers on seismic performance of steel frames to be strengthened. Nonlinear time history analysis results of 5 story moment resisting frame showed (53% - 143%) increase in PGA amount that structure can resist and 40% reduction in roof displacement. Using dampers in bracing system in 7 story braced frame caused (54% - 175%) increase in PGA amount that structure can resist, increase in effective equivalent damping to 20% and 72% reduction in base shear. Using the damping strategy, seismic performance of both two type frames got improved from âcollapseâ level to âoperationalâ level.https://modelling.semnan.ac.ir/article_1517_2abb7cea258b3fb5c614de7161d6ae24.pdfSemnan University PressJournal of Modeling in Engineering2008-485461520071222Buckling optimization of multi segment column with variable section (Variable slope)Buckling optimization of multi segment column with variable section (Variable slope)151810.22075/jme.2017.1518FAJournal Article20170128   Abstract  In this study optimization problem of multi-segment column with uniform (constant) and variable section is investigated. Design variables defined to be the radius of gyration and length of each segment. The objective function is critical buckling load. The object (purpose) of optimization is maximization of the buckling load. Several problems with various boundary conditions including clampedâfree, clampedâclamped and pinnedâpinned are solved. For variable section problems, the variation of radius of gyration is a linear function of length assumed. Results for one-segment, two-segment and three-segment column with variable slope are presented. Furthermore for extending (developing) the algorithm, slop of each segment is defined as a optimization parameter and one-segment, two-segment and three-segment columns results are investigated. For a number of problems with constant radius of gyration or partly uniform segment, remaining variables except known values are optimized   Abstract  In this study optimization problem of multi-segment column with uniform (constant) and variable section is investigated. Design variables defined to be the radius of gyration and length of each segment. The objective function is critical buckling load. The object (purpose) of optimization is maximization of the buckling load. Several problems with various boundary conditions including clampedâfree, clampedâclamped and pinnedâpinned are solved. For variable section problems, the variation of radius of gyration is a linear function of length assumed. Results for one-segment, two-segment and three-segment column with variable slope are presented. Furthermore for extending (developing) the algorithm, slop of each segment is defined as a optimization parameter and one-segment, two-segment and three-segment columns results are investigated. For a number of problems with constant radius of gyration or partly uniform segment, remaining variables except known values are optimizedhttps://modelling.semnan.ac.ir/article_1518_68345be9198b661d8feab4ad0d50ab4f.pdfSemnan University PressJournal of Modeling in Engineering2008-485461520071222Failure Mode and Damage Analysis of Concrete StructuresFailure Mode and Damage Analysis of Concrete Structures151910.22075/jme.2017.1519FAJournal Article20170128  Abstract  In order to investigate the performance of the buildings during earthquake it is necessary to perform nonlinear analysis to determine maximum deformations and plastic hinges distribution. Damage analysis is an appropriate method to seismic assessment of the structure. In this paper it is discussed on the results of the nonlinear static and dynamic analysis of the structures in seismic vulnerability. IDARC is used in structural modeling and analyses purposes.  Abstract  In order to investigate the performance of the buildings during earthquake it is necessary to perform nonlinear analysis to determine maximum deformations and plastic hinges distribution. Damage analysis is an appropriate method to seismic assessment of the structure. In this paper it is discussed on the results of the nonlinear static and dynamic analysis of the structures in seismic vulnerability. IDARC is used in structural modeling and analyses purposes.https://modelling.semnan.ac.ir/article_1519_5f0935e4df2d3d6b1dc2cd845a042e19.pdfSemnan University PressJournal of Modeling in Engineering2008-485461520071222Application of Modal Testing in Model Updating of StructuresApplication of Modal Testing in Model Updating of Structures152010.22075/jme.2017.1520FAJournal Article20170128 Abstract  Apart from the analytical approach to develop a dynamic model for a mechanical structure, another approach is to establish an experimental model for the structure by performing vibration tests and subsequent analysis on the measured data. This process is known as âModal Testingâ. During the last three decades or so, modal testing has developed both in theory and in practice.  One of the most important applications of modal testing is the validation of the mathematical models of dynamic structures by comparing the experimentally driven modal parameters with those of analytical models. Once the analytical model is validated, it can be used with confidence for further analysis such as response prediction, structural coupling, stress analysis, life time prediction, etc.  In this article, the advantages and disadvantages (or limitations) of one of model updating methods are discussed. A 6 DOF lumped parameter system, is employed to investigate the effectiveness of the "Inverse Eigensensitivity Method" (IEM). Firstly the experimental data were simulated using the analytical model. Secondly error locations are found using macro elements. Finally, experimental dynamic properties obtained from the simulated experimental data are compared with the results of the finite element analysis and mass and stiffness error matrices are calculated by using Inverse Eigensensitivity Method" (IEM). Abstract  Apart from the analytical approach to develop a dynamic model for a mechanical structure, another approach is to establish an experimental model for the structure by performing vibration tests and subsequent analysis on the measured data. This process is known as âModal Testingâ. During the last three decades or so, modal testing has developed both in theory and in practice.  One of the most important applications of modal testing is the validation of the mathematical models of dynamic structures by comparing the experimentally driven modal parameters with those of analytical models. Once the analytical model is validated, it can be used with confidence for further analysis such as response prediction, structural coupling, stress analysis, life time prediction, etc.  In this article, the advantages and disadvantages (or limitations) of one of model updating methods are discussed. A 6 DOF lumped parameter system, is employed to investigate the effectiveness of the "Inverse Eigensensitivity Method" (IEM). Firstly the experimental data were simulated using the analytical model. Secondly error locations are found using macro elements. Finally, experimental dynamic properties obtained from the simulated experimental data are compared with the results of the finite element analysis and mass and stiffness error matrices are calculated by using Inverse Eigensensitivity Method" (IEM).https://modelling.semnan.ac.ir/article_1520_09b052785c129bf3c8fe56445e48e1d1.pdfSemnan University PressJournal of Modeling in Engineering2008-485461520071222Modeling and Seismic Analysis of Buildings with Water Tanks on their RoofModeling and Seismic Analysis of Buildings with Water Tanks on their Roof152110.22075/jme.2017.1521FAJournal Article20170128 Abstract  The existence of containers on buildings in large cities with high earthquake risk has caused many damaging problems during past earthquakes. In addition to financial losses, it might induce uncontrolled fire, water cut and local or global failure of the structure. In this study, the dynamic interaction of water containers built on roof of structures, is investigated by means of a nonlinear software based on Finite Element Method. The tank shell and its water have been modeled as a composite system and the interaction of container and water have been examined.  This seismic control system with its limited potential capability as a tuned liquid damper (TLD) has been employed for 5 and 15-story structures, subjected to various earthquakes. The results gained from the present study can be helpful in investigating the tankâs support conditions and its installation. Based on the numerical results obtained in this paper, frequency content and other earthquake characteristics highly affect the role of water tanks on the seismic performance of lower rise buildings. Abstract  The existence of containers on buildings in large cities with high earthquake risk has caused many damaging problems during past earthquakes. In addition to financial losses, it might induce uncontrolled fire, water cut and local or global failure of the structure. In this study, the dynamic interaction of water containers built on roof of structures, is investigated by means of a nonlinear software based on Finite Element Method. The tank shell and its water have been modeled as a composite system and the interaction of container and water have been examined.  This seismic control system with its limited potential capability as a tuned liquid damper (TLD) has been employed for 5 and 15-story structures, subjected to various earthquakes. The results gained from the present study can be helpful in investigating the tankâs support conditions and its installation. Based on the numerical results obtained in this paper, frequency content and other earthquake characteristics highly affect the role of water tanks on the seismic performance of lower rise buildings.