Pouya Akbari; Vahid Saberi; Hamid Saberi; Faezeh Eslami; Abbasali Sadeghi
Volume 2, Issue 9 , December 2021, , Pages 11-21
Abstract
One of the most important and fundamental issues that civil engineers always deal with today due to its importance is the study of the performance and behavior of structures under different conditions. In addition, in many cases, buildings are analyzed and designed separately and without considering ...
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One of the most important and fundamental issues that civil engineers always deal with today due to its importance is the study of the performance and behavior of structures under different conditions. In addition, in many cases, buildings are analyzed and designed separately and without considering the effect of other elements, including the foundation and soil of the infrastructure, which in many cases creates irreparable risks; Therefore, it is necessary to study and evaluate the effect of soil-structure interaction on the performance and design of buildings in order to manage the cost and time of construction projects. In this study, the performance of steel structures with concentric brace of 5, 10 and 15 floors by considering the interaction of soil structure in three different soil modes using nonlinear dynamic analysis of time history under 3 near-fault earthquakes has been done. The results show that considering the interaction of soil and structure increases the accuracy of structural responses.
Vahid Saberi; Hamid Saberi; Faezeh Eslami; Abbasali Sadeghi
Volume 2, Issue 8 , November 2020, , Pages 38-54
Abstract
In this study, the effect of steel damper with vertical slits on chevron braced frames with the number of different stories is investigated and pushover and cyclic analyses are performed . To evaluate and compare the results, a parametric study is carried out on a steel damper with and without slit. ...
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In this study, the effect of steel damper with vertical slits on chevron braced frames with the number of different stories is investigated and pushover and cyclic analyses are performed . To evaluate and compare the results, a parametric study is carried out on a steel damper with and without slit. Eight model frames such as a single-story in ordinary moment frame, braced frame, chevron braced frame with gusset plate, chevron braced frame equipped by a damper with vertical slits, chevron braced frame with silt damper and three-story chevron braced frame equipped by a damper with vertical slits, five-story chevron braced frame equipped by a damper with vertical slits, eight-story chevron braced frame equipped by damper with vertical slits are modeled and analyzed by finite element method in Abaqus software. The results showed that the braced frame equipped by a damper with vertical slits by its ductile behavior, dissipated a large amount of earthquake input energy and reduced the base shear. The hysteresis curves were stable and without any loss, indicating high energy absorption by chevron braced frame equipped by a damper with vertical slits. In all the chevron braced frame equipped by a damper with vertical slits, the plastic hinges are not formed in the members of structures, and the failure mechanism is concentrated in the damper. The damper with vertical slits reduced the elastic stiffness, secondary stiffness and carrying capacity, which in addition to controlling the drift of the structure, increased the energy absorption capability. The chevron braced frame equipped by a damper with vertical slits had more ductility than other specimens, and according to the results, damper with vertical slits had good seismic performance.
Vahid Saberi; Hamid Saberi; Pouya Akbari; Faezeh Eslami; Abbasali Sadeghi
Volume 2, Issue 8 , November 2020, , Pages 55-71
Abstract
In construction of high-rise buildings, one of the major and effective factors is the final cost of structure. Due to high volume of materials in such sort of projects, the smallest changes in the type and method of joining between the different structural components of these systems may have substantial ...
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In construction of high-rise buildings, one of the major and effective factors is the final cost of structure. Due to high volume of materials in such sort of projects, the smallest changes in the type and method of joining between the different structural components of these systems may have substantial impact on the amount of consumed materials and hence the final cost of the project. Structural systems applied in construction of high-rise buildings must be able to transfer the lateral wind force into the earth. One the systems used in construction of high buildings is outrigger system and truss belt. Optimized location of truss belt and shape of architectural plan have crucial effect on structural performance of the system. The aim of this study is to find the appropriate shape for building plan. In this regard, rectangular shaped plans with different width-to-length ratios, similar areas and different number of caps along the height of the building were constructed. After modeling and sample analysis, different parameters such as shear moment, lateral displacement, base shear, relative lateral displacement and …, were compared. Comparison of curves and analysis of obtained results showed that application of rectangular plan with width-to-length ration of 0.64 has better structural performance efficiency. Also, when lateral wind force is applied, application of truss belt resulted in creation of an inflection point in axial force curve of the columns surrounding the central core in the interval between two belts.
Faezeh Eslami; Abbasali Sadeghi
Volume 2, Issue 7 , October 2020, , Pages 82-96
Abstract
Every topic of architectural criticism is a branch of theoretical issues of architecture that is as a behavior and not just judgment and is an important part of the theoretical foundations of architecture, so that any change in various fields of design, based on architectural criticism. It is dependent ...
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Every topic of architectural criticism is a branch of theoretical issues of architecture that is as a behavior and not just judgment and is an important part of the theoretical foundations of architecture, so that any change in various fields of design, based on architectural criticism. It is dependent and criticism has a serious and undeniable presence in our architectural life. Architectural competitions are one of the emerging points of design criticism. These competitions often lead to detailed and heated debates about how to judge and referee works, which indicates the serious presence of criticism. The results and judging of these architectural competitions will orient the society. In this study, the effect of architectural competitions on the culture and formation of architecture in the country has been studied. In this paper, the content analysis method is used. The data are taken from articles published in specialized journals and these works are considered as informed. It is recommended to modify the flow of design competitions, modify the structure at different levels, and determine the accuracy of the objectives of the regulations and their exact implementation.
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.
Vahid Saberi; Hamid Saberi; Erfan Alipour; Abbasali Sadeghi
Volume 2, Issue 3 , June 2020, , Pages 39-50
Abstract
Due to the seismic dangers in the buildings, it is necessary that engineers consider newer and more suitable ways to resist against the seismic forces regularly. The Buckling Restrained Brace (BRB) are almost the new systems against the seismic forces that generally have more ductility in comparison ...
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Due to the seismic dangers in the buildings, it is necessary that engineers consider newer and more suitable ways to resist against the seismic forces regularly. The Buckling Restrained Brace (BRB) are almost the new systems against the seismic forces that generally have more ductility in comparison with other lateral loading systems. In this study, the building 5 story with eccentric buckling restrained braces are designed by ETABS software and then two dimensional side frame is modelled by ABAQUS software in order to investigate the effect of material and specifications of link beam variations on the cyclic performance of eccentric buckling restrained brace. Therefore, first its link beam was modeled with soft steel ST37, then with high strength steel ST52 and finally with hardening bond and reduced surface area by 20%, 40% and 60% (6 models totally). The results show that the highest resistance is related to the sample whose link beam is with the stiffener. Also, the highest plasticity belongs to the model whose link beam is modeled with ST52.
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.
