hamid kazemi; Mohammad Mahdi Rashidian; Ehsan Fereshtehpour
Abstract
Buildings can be affected by special loads such as earthquakes, storms, fires or explosions, that each one can cause the destruction of the structure. In some cases, the structures may be affected by these loads Simultaneously, but there are not also any regulations in existing codes in this regard. ...
Read More
Buildings can be affected by special loads such as earthquakes, storms, fires or explosions, that each one can cause the destruction of the structure. In some cases, the structures may be affected by these loads Simultaneously, but there are not also any regulations in existing codes in this regard. Since many buildings have suffered small or large fires in the recent years in Iran, and on the other hand, Iran is located in a high risk zone of earthquakes, it is needed to control the seismic performance of the building after the fire experience can be considered as an important issue. In this regard, the studies have conducted so far have mostly focused on moment resisting frame structures, so in this paper, using ABAQUS software, the seismic behavior of steel braced frames structural system have been investigated. The results of the pushover analysis show that the ultimate strength and ductility capacity of the steel braced frames after fire can be significantly reduced, which is aggravated by increasing the number of floors.
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, ...
Read More
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 ...
Read More
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, ...
Read More
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.
