Masoud Paknahad - Academia.edu (original) (raw)

Papers by Masoud Paknahad

Civil engineering and architecture, Dec 31, 2023

The stability of soil slopes and determination of stability safety factors have always been the s... more The stability of soil slopes and determination of stability safety factors have always been the subject of study for engineers and researchers. The factor safety of slopes can be determined by using the methods of limit equilibrium method (LEM), strength reduction method (SRM), and limit analysis. The equilibrium method determines the slope safety factor based on the equilibrium of the inter-slice force and without the analysis of tension and strain. In the strength reduction method, based on the tension-strain analysis, the strength of various points of the slope is reduced until it reaches the critical state, and by connecting all of the critical points, the critical rupture level will be obtained. Finite element software and finite difference software determine the safety factors in soil slopes by using the concepts of the strength reduction method. In this study, the safety factors of soil slopes are determined by using ABAQUS software and by using the concept of strength reduction method. Like other types of software, there is no option in ABAQUS for the determination of safety factors and it should be obtained by defining the concepts of strength reduction.

Vast researches have been performed in the eld of earth slope stability analysis including limit ... more Vast researches have been performed in the eld of earth slope stability analysis including limit equilibrium, strength reduction, and limit analysis methods. All the available methods present slope safety factors in a range with a bit of difference and con rm each other. Validation of analytical results performs with instrumentation in actual slopes existing in the eld. Also, another approach that uses for validating results is experimental modeling. The physical modeling requires manufacturing of the intended model in the laboratory concerning the reducing effect of dimensions on the other parameters. This paper investigates slope safety factors against sliding by simulating the slopes in the laboratory and with an image processing system. The test container has dimensions of 1.5×1.5×2 m. The results have illustrated the crest displacement in reinforced slope, with increasing slope angle 13 degrees, is 30 mm in the experimental test and 13 mm in numerical modeling. In the unreinforced slopes, when the slope angle increased by 8 degrees, the experiment test failed, and the factor of safety in the numerical modeling is less than one.

Iranian Journal of Science and Technology-Transactions of Civil Engineering, Jan 8, 2021

Conventional methods of seismic rehabilitation with steel bracing could not be a proper method fo... more Conventional methods of seismic rehabilitation with steel bracing could not be a proper method for upgrading of buildings with these methods due to the cost and time expenses. Therefore, an innovative passive control system called braced damper for steel frames has been introduced in this study. Thus, for investigating the behavior of this structural damper, a single-bay steel frame is formed without rotary brace damper device. Later, the frame is equipped with rotary brace damper and subjected to monotonic and cyclic loading. Few response parameters are regarded, and the performance of the rotary brace damper in reducing each response has been measured. In terms of methodology, ANFIS (Adaptive neuro-fuzzy inference system) is used in data analysis in a variable selection processing to distinguish the predominant values that influence the strength of this damper. The process is on the basis of the variable search method that has been later applied to measure how the four parameters of (1) displacement, (2) diameter (3) thickness, and (4) plate thickness influence the strength of damper. As a result, displacement is the most effectual parameter in forcing prediction and best predictor of accuracy.

IOP conference series, Nov 25, 2019

Highway bridges in seismic prone areas suffer a serious structural issue when subjected to a seve... more Highway bridges in seismic prone areas suffer a serious structural issue when subjected to a severe earthquake, which are the longitudinal hinge displacements. The hinge displacements might put the structure integrity in jeopardy when they exceed certain limits. High hinge displacements can cause fatal effects on the bridge structure including; bearing failure, unseating, and pounding of the adjacent superstructure decks. The aim of this study is to implement a numerical model which characterize the standard properties of a highway bridge and put it under a high intensity seismic excitation to examine its response. Then attempting to enhance the structure response using cable restrainers as means of displacement control. A parametric study is to be performed to investigate the effect of the restrainer material properties (Stiffness and Effective damping) on the efficiency of the cable restrainer in performing its intended purpose. The bridge was modelled and analysed using CSIBridge® finite element package. The obtained results have demonstrated a hazardous response of the bridge without the cable restrainer. However, a significant control capability was observed when applying the cable restrainer. Moreover, the parametric study has shown that, the performance of the cable restrainer is closely related to its stiffness as the stiffness value significantly contributes to displacement control and response stabilization. On the other hand, the effect of the effective damping value on the overall response was limited. Optimum cable restrainer have be chosen based on the parametric study and implemented to the model. The response was compared to the initial response without the restrainer. Eventually, the use of the cable restrainer had provided an impressive efficiency on displacement control and response stabilization.

IOP conference series, Nov 25, 2019

There are many problems in civil engineering which are involving some kind of structural element ... more There are many problems in civil engineering which are involving some kind of structural element in straight connection with the land. When there is some forces are applied to the structural element, both component (structural element and soil/ground) must deform and move in compatible manner. These types of problems are referred as Soil-Structure Interaction (SSI) problem. In this project, an analysis of a building on the slope (10˚) with 5 stories was carried out. The soil under the building are make up by 8 layers consist different type of material. The study in this project is focusing on development of finite element model in order to analysis of a framed structure foundation comprised of a pile system and soil media resting on a hilly area. A beam bending element that calculate the outcome of transverse shear deformation and the axial interaction is then formulated. Based on the interaction behavior of the superstructure foundation soil system, bending moment in the superstructure is found to increase in the external beam and decrease in the inner beams. The effect of hill slope influences the displacements, and subsequently, the forces in the superstructure. This study also compares the result from SSI program and conventional analysis to find out the weakness of the conventional analysis.

Steel and Composite Structures, 2020

Shape Memory Alloys (SMAs) are new materials used in various fields of science and engineering, o... more Shape Memory Alloys (SMAs) are new materials used in various fields of science and engineering, one of which is civil engineering. Owing to their distinguished capabilities such as super elasticity, energy dissipation, and tolerating cyclic deformations, these materials have been of interest to engineers. On the other hand, the connections of a steel structure are of paramount importance because of their vulnerabilities during an earthquake. Therefore, it is indispensable to find approaches to augment the efficiency and safety of the connection. This research investigates the behavior of steel connections with extended end plates equipped hybridly with 8 rows of high strength bolts as well as Nitinol superelastic SMA bolts. The connections are studied using component method in dual form. In this method, the components affecting the connections behavior, such as beam flange, beam web, column web, extended end plate, and bolts are considered as parallel and series springs according to the Euro-Code3. Then, the nonlinear force- displacement response of the connection is presented in the form of moment-rotation curve. The results obtained from this survey demonstrate that the connection has ductility, in addition to its high strength, due to high ductility of SMA bolts.

Archives of Civil and Mechanical Engineering, Jan 2, 2021

This is the first research on the nonlinear frequency analysis of a multi-scale hybrid nanocompos... more This is the first research on the nonlinear frequency analysis of a multi-scale hybrid nanocomposite (MHC) disk (MHCD) resting on an elastic foundation subjected to nonlinear temperature gradient and mechanical loading is investigated. The matrix material is reinforced with carbon nanotubes (CNTs) or carbon fibers (CF) at the nano-or macroscale, respectively. We present a modified Halpin-Tsai model to predict the effective properties of the MHCD. The displacement-strain of nonlinear vibration of multi-scale laminated disk via third-order shear deformation theory (TSDT) and using Von Karman nonlinear shell theory is obtained. Hamilton's principle is employed to establish the governing equations of motion, which is finally solved by generalized differential quadrature method (GDQM) and perturbation method (PM). Finally, the results show that FG patterns, different orientation angle of the fiber, the V F and W CNT parameters, axial load, nonlinear temperature gradient, and applied temperature of the top surface play an essential impact on the linear and nonlinear dynamic responses of the MHCD. The more significant outcome of this research is that the effects of the V F , W CNT , h, and b parameters on the nonlinear frequency of the MHCD can be considered at the higher value of the large deflection parameter and the effect of negative axial load on the dynamic responses of the structure is more intensive. As an applicable result show that the best functionally graded (FG) pattern for serving the highest nonlinear dynamic response of an MHC reinforced annular plate is FG-A.

Shear wall is commonly employed as a principal element to resist lateral loads due to wind or ear... more Shear wall is commonly employed as a principal element to resist lateral loads due to wind or earthquake forces. An accurate mathematical model for shear wall structure needs to consider the effect of all components in the system i.e. shear wall, foundation, and subsoil. In addition to the necessity for accurate modelling of shear wall-foundation-soil system, the model must be proficient to capture the structural response of the shear wall building-foundation-soil and it should also be computationally efficient. Furthermore, since shear wall is a key structural element which plays a major role to ensure stability of the shear building system under lateral loads, it is essential to consider the inelastic response of the shear wall buildings. With the tremendous advancement in computer technology several finite element software's are commercially available to researchers and engineers. However, this would not serve the objectives of the research investigator. In this study, new elements have been developed, modified constitutive law has been proposed, new computational algorithm has been utilised.

Iranian Journal of Science and Technology-Transactions of Civil Engineering, Feb 10, 2021

Wide researches have been performed in the field of earth slope stability analysis by the use of ... more Wide researches have been performed in the field of earth slope stability analysis by the use of limit equilibrium, strength reduction, and limit analysis methods. All the available methods present slope factor of safeties in a range with a little difference and confirm each other. It could be validated the analytical results by the help of instrumentation in actual slopes existing in the field. In addition, another approach that can be used for the validation of results is experimental modeling. In experimental simulation, it is required to manufacture the intended model in laboratory concerning the effect of reducing dimensions on the other parameters. In the present paper, it is attempted to investigate slope safety factor against sliding by simulating the slope in laboratory using of image processing system. The test container has dimensions of 1.5 × 1.5 × 2 m. The results have illustrated that when slope angle increased 13 degrees, the crest displacement in reinforced slope is 30 mm in the experimental modeling and 13 mm in numerical analysis. In the unreinforced slope, when the slope angle increased 8 degrees the slope failed and factor of safety in the numerical modeling became less than one.

Proceedings of the Tenth International Conference on Civil, Structural and Environmental Engineering Computing

IOP Conference Series: Earth and Environmental Science, 2019

There are many problems in civil engineering which are involving some kind of structural element ... more There are many problems in civil engineering which are involving some kind of structural element in straight connection with the land. When there is some forces are applied to the structural element, both component (structural element and soil/ground) must deform and move in compatible manner. These types of problems are referred as Soil-Structure Interaction (SSI) problem. In this project, an analysis of a building on the slope (10˚) with 5 stories was carried out. The soil under the building are make up by 8 layers consist different type of material. The study in this project is focusing on development of finite element model in order to analysis of a framed structure foundation comprised of a pile system and soil media resting on a hilly area. A beam bending element that calculate the outcome of transverse shear deformation and the axial interaction is then formulated. Based on the interaction behavior of the superstructure foundation soil system, bending moment in the superstruc...

IOP Conference Series: Earth and Environmental Science, 2019

A core system for buildings has been recognized as an effective tool for managing the response of... more A core system for buildings has been recognized as an effective tool for managing the response of the building when an earthquake happens by decoupling the building structure from potentially damaging earthquake-induced forces. A challenging issue in this context is the application of the configuration of the core system. A review of recent studies shows that the configuration of cores has not been substantial investigated. This study presents seismic design concepts in which different configurations of cores are applied to a building. Nine steel buildings were modeled with rectangular core, octagon core, circle core, lozenge core, cross core, multi core, irregular core 1, and irregular core 2. All structural models are subjected to components of the 1940 El Centro earthquake and are evaluated and compared with the response of a structure without core. All models were also compared with and without opening in cores. The performance of the structural models under seismic excitation w...

IOP Conference Series: Earth and Environmental Science, 2019

A core system for buildings has been recognized as an effective tool for managing the response of... more A core system for buildings has been recognized as an effective tool for managing the response of the building when an earthquake happens by decoupling the building structure from potentially damaging earthquake-induced forces. A challenging issue in this context is the application of the configuration of the core system. A review of recent studies shows that the configuration of cores has not been substantial investigated. This study presents seismic design concepts in which different configurations of cores are applied to a building. Nine steel buildings were modeled with rectangular core, octagon core, circle core, lozenge core, cross core, multi core, irregular core 1, and irregular core 2. All structural models are subjected to components of the 1940 El Centro earthquake and are evaluated and compared with the response of a structure without core. All models were also compared with and without opening in cores. The performance of the structural models under seismic excitation w...

The stability of soil slopes and the determination of safety factors have always been the subject... more The stability of soil slopes and the determination of safety factors have always been the subject of study for engineers and researchers. The safety factor of slopes can be determined by using the methods of limit equilibrium method (L.E.M.), limit analysis, and strength reduction method (S.R.M.). The equilibrium method determines the slope safety factor based on the equilibrium of the inter-slice force and without the analysis of tension and strain. In the strength reduction method, based on the tension-strain analysis, the strength of various points of the slope is reduced until it reaches the critical state, and by connecting all of the critical points, the critical rupture level will be obtained. Finite element software and finite difference software determine the safety factors in soil slopes by using the concepts of the strength reduction method. In this paper, the safety factors of soil slopes are determined by using ABAQUS software, and using the concept of strength reductio...

Iranian Journal of Science and Technology, Transactions of Civil Engineering, 2021

Conventional methods of seismic rehabilitation with steel bracing could not be a proper method fo... more Conventional methods of seismic rehabilitation with steel bracing could not be a proper method for upgrading of buildings with these methods due to the cost and time expenses. Therefore, an innovative passive control system called braced damper for steel frames has been introduced in this study. Thus, for investigating the behavior of this structural damper, a single-bay steel frame is formed without rotary brace damper device. Later, the frame is equipped with rotary brace damper and subjected to monotonic and cyclic loading. Few response parameters are regarded, and the performance of the rotary brace damper in reducing each response has been measured. In terms of methodology, ANFIS (Adaptive neuro-fuzzy inference system) is used in data analysis in a variable selection processing to distinguish the predominant values that influence the strength of this damper. The process is on the basis of the variable search method that has been later applied to measure how the four parameters of (1) displacement, (2) diameter (3) thickness, and (4) plate thickness influence the strength of damper. As a result, displacement is the most effectual parameter in forcing prediction and best predictor of accuracy.

ABSTRACT Shear wall is commonly employed as a principal element to resist lateral loads due to wi... more ABSTRACT Shear wall is commonly employed as a principal element to resist lateral loads due to wind or earthquake forces. An accurate model for shear wall system needs to consider the effect of all components for analyses i.e. shear wall, foundation and subsoil. This investigation presents modeling of shear wall structure - foundation and soil system using the super element, finite and infinite elements after considering soil nonlinearity. A finite element program has been written based on the proposed physical and material model for the analysis of the system. The applicability of the proposed idealization has been shown by analyzing a shear wall structure under static loading. In order to explore the efficiency of using super elements, an attempt has also been made to model the shear wall building using fully conventional finite element discretization. Furthermore the paper investigates the necessity of including soil structure interaction in analyzing shear wall structures. The results obtained from the analysis of shear wall model considering five different types of soil for the soil media show that the influence of soil interaction is very significant in the displacement as well as stresses induced in shear wall. Furthermore this investigation highlighted the effect of considering nonlinearity of soil in total displacement and stresses in shear wall system.

Shear wall is commonly employed as a principal element to resist lateral loads due to wind or ear... more Shear wall is commonly employed as a principal element to resist lateral loads due to wind or earthquake forces. An accurate mathematical model for shear wall structure needs to consider the effect of all components in the system i.e. shear wall, foundation, and subsoil. In addition to the necessity for accurate modelling of shear wall-foundation-soil system, the model must be proficient to capture the structural response of the shear wall building-foundation-soil and it should also be computationally efficient. Furthermore, since shear wall is a key structural element which plays a major role to ensure stability of the shear building system under lateral loads, it is essential to consider the inelastic response of the shear wall buildings. With the tremendous advancement in computer technology several finite element software's are commercially available to researchers and engineers. However, this would not serve the objectives of the research investigator. In this study, new elements have been developed, modified constitutive law has been proposed, new computational algorithm has been utilised.

Crack propagation modeling in quasi-brittle materials such as concrete is essential for improving... more Crack propagation modeling in quasi-brittle materials such as concrete is essential for improving the reliability and load-bearing capacity assessment. Crack propagation explains many failure characteristics of concrete structures using the fracture mechanics approach. This approach could better explain the softening behavior of concrete structures. A great effort has been made in developing numerical models; however, some models involve complex expressions with too many parameters, and the results are in some cases inaccurate. In this investigation, a numerical approach is developed to model the fracture process zone (FPZ). Based on the modified crack closure integral (MCCI) method, a new nonlinear spring is proposed to be placed between the interfacial node pairs to model crack propagation. A new strain energy release rates for Mode I is calculated as a function of opening in the softening part. Two benchmark beams are simulated by the ABAQUS software for the accuracy of cohesive ...

Steel and Composite Structures, 2018

In this research the effect of high strength concrete (HSC) on shear capability of the channel sh... more In this research the effect of high strength concrete (HSC) on shear capability of the channel shear connectors (CSC) in the steel concrete composite floor system was estimated experimentally and analytically. The push-out test was carried out for assessing the accurateness of the proposed model (nonlinear and finite element model) for the test specimens. A parametric analysis was conducted for predicting the shear capacity of the connectors (CSC) in the HSC. Eight push-out specimens of different sizes of channels with different high strength concrete were tested under the monotonic loading system. The aim of this study was to evaluate the efficacy of the National Building Code of Canada (NBC) of Canada for analysing the loading abilities of the CSC in the HSC. Using the experimental tests results and verifying the finite element results with them, it was then confirmed by the extended parametric studies that the Canadian Design Code was less efficient for predicting the capacity of...

Civil engineering and architecture, Dec 31, 2023

The stability of soil slopes and determination of stability safety factors have always been the s... more The stability of soil slopes and determination of stability safety factors have always been the subject of study for engineers and researchers. The factor safety of slopes can be determined by using the methods of limit equilibrium method (LEM), strength reduction method (SRM), and limit analysis. The equilibrium method determines the slope safety factor based on the equilibrium of the inter-slice force and without the analysis of tension and strain. In the strength reduction method, based on the tension-strain analysis, the strength of various points of the slope is reduced until it reaches the critical state, and by connecting all of the critical points, the critical rupture level will be obtained. Finite element software and finite difference software determine the safety factors in soil slopes by using the concepts of the strength reduction method. In this study, the safety factors of soil slopes are determined by using ABAQUS software and by using the concept of strength reduction method. Like other types of software, there is no option in ABAQUS for the determination of safety factors and it should be obtained by defining the concepts of strength reduction.

Vast researches have been performed in the eld of earth slope stability analysis including limit ... more Vast researches have been performed in the eld of earth slope stability analysis including limit equilibrium, strength reduction, and limit analysis methods. All the available methods present slope safety factors in a range with a bit of difference and con rm each other. Validation of analytical results performs with instrumentation in actual slopes existing in the eld. Also, another approach that uses for validating results is experimental modeling. The physical modeling requires manufacturing of the intended model in the laboratory concerning the reducing effect of dimensions on the other parameters. This paper investigates slope safety factors against sliding by simulating the slopes in the laboratory and with an image processing system. The test container has dimensions of 1.5×1.5×2 m. The results have illustrated the crest displacement in reinforced slope, with increasing slope angle 13 degrees, is 30 mm in the experimental test and 13 mm in numerical modeling. In the unreinforced slopes, when the slope angle increased by 8 degrees, the experiment test failed, and the factor of safety in the numerical modeling is less than one.

Iranian Journal of Science and Technology-Transactions of Civil Engineering, Jan 8, 2021

Conventional methods of seismic rehabilitation with steel bracing could not be a proper method fo... more Conventional methods of seismic rehabilitation with steel bracing could not be a proper method for upgrading of buildings with these methods due to the cost and time expenses. Therefore, an innovative passive control system called braced damper for steel frames has been introduced in this study. Thus, for investigating the behavior of this structural damper, a single-bay steel frame is formed without rotary brace damper device. Later, the frame is equipped with rotary brace damper and subjected to monotonic and cyclic loading. Few response parameters are regarded, and the performance of the rotary brace damper in reducing each response has been measured. In terms of methodology, ANFIS (Adaptive neuro-fuzzy inference system) is used in data analysis in a variable selection processing to distinguish the predominant values that influence the strength of this damper. The process is on the basis of the variable search method that has been later applied to measure how the four parameters of (1) displacement, (2) diameter (3) thickness, and (4) plate thickness influence the strength of damper. As a result, displacement is the most effectual parameter in forcing prediction and best predictor of accuracy.

IOP conference series, Nov 25, 2019

Highway bridges in seismic prone areas suffer a serious structural issue when subjected to a seve... more Highway bridges in seismic prone areas suffer a serious structural issue when subjected to a severe earthquake, which are the longitudinal hinge displacements. The hinge displacements might put the structure integrity in jeopardy when they exceed certain limits. High hinge displacements can cause fatal effects on the bridge structure including; bearing failure, unseating, and pounding of the adjacent superstructure decks. The aim of this study is to implement a numerical model which characterize the standard properties of a highway bridge and put it under a high intensity seismic excitation to examine its response. Then attempting to enhance the structure response using cable restrainers as means of displacement control. A parametric study is to be performed to investigate the effect of the restrainer material properties (Stiffness and Effective damping) on the efficiency of the cable restrainer in performing its intended purpose. The bridge was modelled and analysed using CSIBridge® finite element package. The obtained results have demonstrated a hazardous response of the bridge without the cable restrainer. However, a significant control capability was observed when applying the cable restrainer. Moreover, the parametric study has shown that, the performance of the cable restrainer is closely related to its stiffness as the stiffness value significantly contributes to displacement control and response stabilization. On the other hand, the effect of the effective damping value on the overall response was limited. Optimum cable restrainer have be chosen based on the parametric study and implemented to the model. The response was compared to the initial response without the restrainer. Eventually, the use of the cable restrainer had provided an impressive efficiency on displacement control and response stabilization.

IOP conference series, Nov 25, 2019

There are many problems in civil engineering which are involving some kind of structural element ... more There are many problems in civil engineering which are involving some kind of structural element in straight connection with the land. When there is some forces are applied to the structural element, both component (structural element and soil/ground) must deform and move in compatible manner. These types of problems are referred as Soil-Structure Interaction (SSI) problem. In this project, an analysis of a building on the slope (10˚) with 5 stories was carried out. The soil under the building are make up by 8 layers consist different type of material. The study in this project is focusing on development of finite element model in order to analysis of a framed structure foundation comprised of a pile system and soil media resting on a hilly area. A beam bending element that calculate the outcome of transverse shear deformation and the axial interaction is then formulated. Based on the interaction behavior of the superstructure foundation soil system, bending moment in the superstructure is found to increase in the external beam and decrease in the inner beams. The effect of hill slope influences the displacements, and subsequently, the forces in the superstructure. This study also compares the result from SSI program and conventional analysis to find out the weakness of the conventional analysis.

Steel and Composite Structures, 2020

Shape Memory Alloys (SMAs) are new materials used in various fields of science and engineering, o... more Shape Memory Alloys (SMAs) are new materials used in various fields of science and engineering, one of which is civil engineering. Owing to their distinguished capabilities such as super elasticity, energy dissipation, and tolerating cyclic deformations, these materials have been of interest to engineers. On the other hand, the connections of a steel structure are of paramount importance because of their vulnerabilities during an earthquake. Therefore, it is indispensable to find approaches to augment the efficiency and safety of the connection. This research investigates the behavior of steel connections with extended end plates equipped hybridly with 8 rows of high strength bolts as well as Nitinol superelastic SMA bolts. The connections are studied using component method in dual form. In this method, the components affecting the connections behavior, such as beam flange, beam web, column web, extended end plate, and bolts are considered as parallel and series springs according to the Euro-Code3. Then, the nonlinear force- displacement response of the connection is presented in the form of moment-rotation curve. The results obtained from this survey demonstrate that the connection has ductility, in addition to its high strength, due to high ductility of SMA bolts.

Archives of Civil and Mechanical Engineering, Jan 2, 2021

This is the first research on the nonlinear frequency analysis of a multi-scale hybrid nanocompos... more This is the first research on the nonlinear frequency analysis of a multi-scale hybrid nanocomposite (MHC) disk (MHCD) resting on an elastic foundation subjected to nonlinear temperature gradient and mechanical loading is investigated. The matrix material is reinforced with carbon nanotubes (CNTs) or carbon fibers (CF) at the nano-or macroscale, respectively. We present a modified Halpin-Tsai model to predict the effective properties of the MHCD. The displacement-strain of nonlinear vibration of multi-scale laminated disk via third-order shear deformation theory (TSDT) and using Von Karman nonlinear shell theory is obtained. Hamilton's principle is employed to establish the governing equations of motion, which is finally solved by generalized differential quadrature method (GDQM) and perturbation method (PM). Finally, the results show that FG patterns, different orientation angle of the fiber, the V F and W CNT parameters, axial load, nonlinear temperature gradient, and applied temperature of the top surface play an essential impact on the linear and nonlinear dynamic responses of the MHCD. The more significant outcome of this research is that the effects of the V F , W CNT , h, and b parameters on the nonlinear frequency of the MHCD can be considered at the higher value of the large deflection parameter and the effect of negative axial load on the dynamic responses of the structure is more intensive. As an applicable result show that the best functionally graded (FG) pattern for serving the highest nonlinear dynamic response of an MHC reinforced annular plate is FG-A.

Shear wall is commonly employed as a principal element to resist lateral loads due to wind or ear... more Shear wall is commonly employed as a principal element to resist lateral loads due to wind or earthquake forces. An accurate mathematical model for shear wall structure needs to consider the effect of all components in the system i.e. shear wall, foundation, and subsoil. In addition to the necessity for accurate modelling of shear wall-foundation-soil system, the model must be proficient to capture the structural response of the shear wall building-foundation-soil and it should also be computationally efficient. Furthermore, since shear wall is a key structural element which plays a major role to ensure stability of the shear building system under lateral loads, it is essential to consider the inelastic response of the shear wall buildings. With the tremendous advancement in computer technology several finite element software's are commercially available to researchers and engineers. However, this would not serve the objectives of the research investigator. In this study, new elements have been developed, modified constitutive law has been proposed, new computational algorithm has been utilised.

Iranian Journal of Science and Technology-Transactions of Civil Engineering, Feb 10, 2021

Wide researches have been performed in the field of earth slope stability analysis by the use of ... more Wide researches have been performed in the field of earth slope stability analysis by the use of limit equilibrium, strength reduction, and limit analysis methods. All the available methods present slope factor of safeties in a range with a little difference and confirm each other. It could be validated the analytical results by the help of instrumentation in actual slopes existing in the field. In addition, another approach that can be used for the validation of results is experimental modeling. In experimental simulation, it is required to manufacture the intended model in laboratory concerning the effect of reducing dimensions on the other parameters. In the present paper, it is attempted to investigate slope safety factor against sliding by simulating the slope in laboratory using of image processing system. The test container has dimensions of 1.5 × 1.5 × 2 m. The results have illustrated that when slope angle increased 13 degrees, the crest displacement in reinforced slope is 30 mm in the experimental modeling and 13 mm in numerical analysis. In the unreinforced slope, when the slope angle increased 8 degrees the slope failed and factor of safety in the numerical modeling became less than one.

Proceedings of the Tenth International Conference on Civil, Structural and Environmental Engineering Computing

IOP Conference Series: Earth and Environmental Science, 2019

There are many problems in civil engineering which are involving some kind of structural element ... more There are many problems in civil engineering which are involving some kind of structural element in straight connection with the land. When there is some forces are applied to the structural element, both component (structural element and soil/ground) must deform and move in compatible manner. These types of problems are referred as Soil-Structure Interaction (SSI) problem. In this project, an analysis of a building on the slope (10˚) with 5 stories was carried out. The soil under the building are make up by 8 layers consist different type of material. The study in this project is focusing on development of finite element model in order to analysis of a framed structure foundation comprised of a pile system and soil media resting on a hilly area. A beam bending element that calculate the outcome of transverse shear deformation and the axial interaction is then formulated. Based on the interaction behavior of the superstructure foundation soil system, bending moment in the superstruc...

IOP Conference Series: Earth and Environmental Science, 2019

A core system for buildings has been recognized as an effective tool for managing the response of... more A core system for buildings has been recognized as an effective tool for managing the response of the building when an earthquake happens by decoupling the building structure from potentially damaging earthquake-induced forces. A challenging issue in this context is the application of the configuration of the core system. A review of recent studies shows that the configuration of cores has not been substantial investigated. This study presents seismic design concepts in which different configurations of cores are applied to a building. Nine steel buildings were modeled with rectangular core, octagon core, circle core, lozenge core, cross core, multi core, irregular core 1, and irregular core 2. All structural models are subjected to components of the 1940 El Centro earthquake and are evaluated and compared with the response of a structure without core. All models were also compared with and without opening in cores. The performance of the structural models under seismic excitation w...

IOP Conference Series: Earth and Environmental Science, 2019

A core system for buildings has been recognized as an effective tool for managing the response of... more A core system for buildings has been recognized as an effective tool for managing the response of the building when an earthquake happens by decoupling the building structure from potentially damaging earthquake-induced forces. A challenging issue in this context is the application of the configuration of the core system. A review of recent studies shows that the configuration of cores has not been substantial investigated. This study presents seismic design concepts in which different configurations of cores are applied to a building. Nine steel buildings were modeled with rectangular core, octagon core, circle core, lozenge core, cross core, multi core, irregular core 1, and irregular core 2. All structural models are subjected to components of the 1940 El Centro earthquake and are evaluated and compared with the response of a structure without core. All models were also compared with and without opening in cores. The performance of the structural models under seismic excitation w...

The stability of soil slopes and the determination of safety factors have always been the subject... more The stability of soil slopes and the determination of safety factors have always been the subject of study for engineers and researchers. The safety factor of slopes can be determined by using the methods of limit equilibrium method (L.E.M.), limit analysis, and strength reduction method (S.R.M.). The equilibrium method determines the slope safety factor based on the equilibrium of the inter-slice force and without the analysis of tension and strain. In the strength reduction method, based on the tension-strain analysis, the strength of various points of the slope is reduced until it reaches the critical state, and by connecting all of the critical points, the critical rupture level will be obtained. Finite element software and finite difference software determine the safety factors in soil slopes by using the concepts of the strength reduction method. In this paper, the safety factors of soil slopes are determined by using ABAQUS software, and using the concept of strength reductio...

Iranian Journal of Science and Technology, Transactions of Civil Engineering, 2021

Conventional methods of seismic rehabilitation with steel bracing could not be a proper method fo... more Conventional methods of seismic rehabilitation with steel bracing could not be a proper method for upgrading of buildings with these methods due to the cost and time expenses. Therefore, an innovative passive control system called braced damper for steel frames has been introduced in this study. Thus, for investigating the behavior of this structural damper, a single-bay steel frame is formed without rotary brace damper device. Later, the frame is equipped with rotary brace damper and subjected to monotonic and cyclic loading. Few response parameters are regarded, and the performance of the rotary brace damper in reducing each response has been measured. In terms of methodology, ANFIS (Adaptive neuro-fuzzy inference system) is used in data analysis in a variable selection processing to distinguish the predominant values that influence the strength of this damper. The process is on the basis of the variable search method that has been later applied to measure how the four parameters of (1) displacement, (2) diameter (3) thickness, and (4) plate thickness influence the strength of damper. As a result, displacement is the most effectual parameter in forcing prediction and best predictor of accuracy.

ABSTRACT Shear wall is commonly employed as a principal element to resist lateral loads due to wi... more ABSTRACT Shear wall is commonly employed as a principal element to resist lateral loads due to wind or earthquake forces. An accurate model for shear wall system needs to consider the effect of all components for analyses i.e. shear wall, foundation and subsoil. This investigation presents modeling of shear wall structure - foundation and soil system using the super element, finite and infinite elements after considering soil nonlinearity. A finite element program has been written based on the proposed physical and material model for the analysis of the system. The applicability of the proposed idealization has been shown by analyzing a shear wall structure under static loading. In order to explore the efficiency of using super elements, an attempt has also been made to model the shear wall building using fully conventional finite element discretization. Furthermore the paper investigates the necessity of including soil structure interaction in analyzing shear wall structures. The results obtained from the analysis of shear wall model considering five different types of soil for the soil media show that the influence of soil interaction is very significant in the displacement as well as stresses induced in shear wall. Furthermore this investigation highlighted the effect of considering nonlinearity of soil in total displacement and stresses in shear wall system.

Shear wall is commonly employed as a principal element to resist lateral loads due to wind or ear... more Shear wall is commonly employed as a principal element to resist lateral loads due to wind or earthquake forces. An accurate mathematical model for shear wall structure needs to consider the effect of all components in the system i.e. shear wall, foundation, and subsoil. In addition to the necessity for accurate modelling of shear wall-foundation-soil system, the model must be proficient to capture the structural response of the shear wall building-foundation-soil and it should also be computationally efficient. Furthermore, since shear wall is a key structural element which plays a major role to ensure stability of the shear building system under lateral loads, it is essential to consider the inelastic response of the shear wall buildings. With the tremendous advancement in computer technology several finite element software's are commercially available to researchers and engineers. However, this would not serve the objectives of the research investigator. In this study, new elements have been developed, modified constitutive law has been proposed, new computational algorithm has been utilised.

Crack propagation modeling in quasi-brittle materials such as concrete is essential for improving... more Crack propagation modeling in quasi-brittle materials such as concrete is essential for improving the reliability and load-bearing capacity assessment. Crack propagation explains many failure characteristics of concrete structures using the fracture mechanics approach. This approach could better explain the softening behavior of concrete structures. A great effort has been made in developing numerical models; however, some models involve complex expressions with too many parameters, and the results are in some cases inaccurate. In this investigation, a numerical approach is developed to model the fracture process zone (FPZ). Based on the modified crack closure integral (MCCI) method, a new nonlinear spring is proposed to be placed between the interfacial node pairs to model crack propagation. A new strain energy release rates for Mode I is calculated as a function of opening in the softening part. Two benchmark beams are simulated by the ABAQUS software for the accuracy of cohesive ...

Steel and Composite Structures, 2018

In this research the effect of high strength concrete (HSC) on shear capability of the channel sh... more In this research the effect of high strength concrete (HSC) on shear capability of the channel shear connectors (CSC) in the steel concrete composite floor system was estimated experimentally and analytically. The push-out test was carried out for assessing the accurateness of the proposed model (nonlinear and finite element model) for the test specimens. A parametric analysis was conducted for predicting the shear capacity of the connectors (CSC) in the HSC. Eight push-out specimens of different sizes of channels with different high strength concrete were tested under the monotonic loading system. The aim of this study was to evaluate the efficacy of the National Building Code of Canada (NBC) of Canada for analysing the loading abilities of the CSC in the HSC. Using the experimental tests results and verifying the finite element results with them, it was then confirmed by the extended parametric studies that the Canadian Design Code was less efficient for predicting the capacity of...