Kourosh Mehdizadeh; Faezeh Eslami; Seyede Vahide Hashemi; Abbasali Sadeghi; Gholamreza Shobeyri
Volume 2, Issue 7 , October 2020, , Pages 97-117
Abstract
In recent years, the discussion of nonlinear behavior in seismic evaluation of structures has been raised. One of the best and newest methods of evaluating buildings is the use of nonlinear dynamic analysis. This type of analysis shows a comprehensive behavior of structures in the linear to nonlinear ...
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In recent years, the discussion of nonlinear behavior in seismic evaluation of structures has been raised. One of the best and newest methods of evaluating buildings is the use of nonlinear dynamic analysis. This type of analysis shows a comprehensive behavior of structures in the linear to nonlinear domain. In this study, in addition to nonlinear dynamic analysis, in order to match the reality, seismic components with different angles have been applied to the structure to show a more accurate seismic evaluation of the structure. In this research, steel buildings with intermediate moment-resisting frame was modelled in three dimensional state in SAP2000 software with 8 and 12 stories and square and rectangular planes and their seismic performances have been studied and compared according to the angle of 8 pairs of accelograms (16 accelograms) under near and far-fault earthquakes (0, 30, 60 and 90 degree) using nonlinear dynamic time history analysis. The results showed that the performance of the structures at angles of 60 and 90 degree was more critical due to the larger seismic responses. Also, in most accelograms, the height of the structure was more effective than the plan shape on seismic responses. In addition, the studied structures had more critical seismic responses due to near-fault earthquakes compared to far-fault earthquakes.
Kourosh Mehdizadeh; Seyede Vahide Hashemi; Abbasali Sadeghi; Nastran Abdollahi
Volume 2, Issue 3 , June 2020, , Pages 11-33
Abstract
Reinforcement of weak concrete structures against lateral loads is essential. Rehabilitation of existing structures is one of the important issues of the day in the construction industry in Iran and even in other countries. Due to the fact that many structures are almost impossible to use due to reasons, ...
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Reinforcement of weak concrete structures against lateral loads is essential. Rehabilitation of existing structures is one of the important issues of the day in the construction industry in Iran and even in other countries. Due to the fact that many structures are almost impossible to use due to reasons, type of use, the presence of important equipment, the importance of building and many other things, the need for retrofitting is felt more and more. Today, there are many varied methods in rehabilitating structures around the world, which is used in the field of knowledge and technology and the needs of the region. In our country, some methods are used, such as the use of concrete armored and steel armored vehicles, the use of polymer fibers, seismic separators, the addition of concrete and steel shear walls and the addition of braces and so on. Each of the above methods may be suggested for reasons such as structural weakness, time and economic efficiency, user continuity during retrofitting, maintaining architecture, and most importantly, answering technical and computational design. Each of the above methods may be suggested for reasons such as structural weakness, time and economic efficiency, user continuity during retrofitting, maintaining architecture, and most importantly, answering technical and computational design. Among the existing methods, the use of unbreakable steel bracelets is one of the main recommendations. In this study, 6 samples of braided curtain braced frame were made by a bulking resistant brace and analyzed using ABAQUS software.
Kourosh Mehdizadeh; Seyede Vahide Hashemi; Abbasali Sadeghi; Farshid Movafegh Ghadirli
Volume 2, Issue 2 , May 2020, , Pages 56-76
Abstract
Today, the use of high strength concrete in large projects around the world has become very common. It is almost impossible to build the world's largest and tallest structures without using high strength concrete technology. On the other hand, due to the wide range of concrete structures in our country, ...
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Today, the use of high strength concrete in large projects around the world has become very common. It is almost impossible to build the world's largest and tallest structures without using high strength concrete technology. On the other hand, due to the wide range of concrete structures in our country, the regulations for the design of concrete structures do not mention the effects of concrete strength on the dynamic performance of the structure; Therefore, the aim of this study is to investigate the seismic performance of concrete structure with common and high strength concrete by using nonlinear dynamic time history analysis, so that the effect of parameters such as roof displacement, base shear, and axial force of the columns is compared. Therefore, at first, 2-storey concrete moment frame structure with intermediate ductility was designed in three-dimensional mode, according to the available regulations, then the real details were modeled in ABAQUS software. In order to perform nonlinear analysis, nonlinear model is used for structural elements and seismic analysis of the system is performed using three near-fault pairs of accelograms. The results show that increasing the strength of the concrete increasing the base shear as well as the stiffness of the stories, and the axial force values of the columns is almost ineffective.
Abbasali Sadeghi; Seyede Vahide Hashemi; Kourosh Mehdizadeh
Volume 2, Issue 1 , April 2020, , Pages 41-60
Abstract
In recent years, with the advancement of technology related to structural computations and the significant increasing in knowledge and experience about the seismic behavior of structures, the study of their failure rate has become more serious, so it is necessary to define damage indices (DIs) are those ...
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In recent years, with the advancement of technology related to structural computations and the significant increasing in knowledge and experience about the seismic behavior of structures, the study of their failure rate has become more serious, so it is necessary to define damage indices (DIs) are those that express amount of failure quantitatively and qualitatively. In many cases, Damage indices are dimensionless parameters, the range of which is usually between zero for no damage state and one for the structural collapse, and the values between these two indices are shown different damage states. In this study, in order to evaluate and prioritize damage indices, four types of irregular intermediate ductility steel moment-resisting frame structure (mass irregularity) with 2, 5, 8 and 12-story were designed in Etabs software and then nonlinear dynamic time history analysis has been performed under far-fault earthquakes using SeismoStruct software so the parameters needed to obtain structural damage indices such as local indices like local indices: interstory drift, maximum roof displacement, banon failure, kinematic, banon normalized cumulative rotation, cumulative plastic rotation, ductility and park-ang and also global indices: park-ang, energy, roufaiel and meyer, papadopoulos, sozen, rosenblueth, ductility, hysteretic energy, Park-Ang and base shear, banon failure (weighted index) and interstory rotation have been derived, calculated and prioritized.
