Sharif Digital Repository

In this thesis, the behavior of proposed moment resisting precast beam-column concrete connection under cyclic and monotonic loads is investigated. In this study, the finite element models of precast and monolithic middle and corner connections are created. The results of finite element analysis under cyclic loading is verified with existing experimental results based on failure mode, ductility, energy dissipation capacity and flexural strength. Based on the results of nonlinear finite element analysis, the analytical behavior of samples is in good agreement with experimental results and finite element analysis of proposed precast connection can be replaced with supplementary tests. Then the... 

Using mixed building system of structural steel and reinforced concrete improves the resistance of the structure in comparison with using either material alone. Coupled shear walls is one of these new systems. Coupled shear walls by definition is a series of walls coupled by beams as a central core structure with opening to accommodate doors, elevator wells, windows and corridors. Coupled shear walls can provide an efficient structural system to resist horizontal force due to axial and seismic loads. One type of coupled beams is Steel Coupling Beams (SCB) which consists of steel beams and reinforced concrete shear walls which represents a cost and time-effective type of construction. Some... 

Performance of reinforced concrete frames is highly dependent on detailing of the joint connections between its members, such as beams and columns. To have a good structural behavior, joints must show ductile behavior and designed based on the philosophy of strong column-weak beam. In the case of sever lacking ductility, strength or even rigidity of the connections, or having a weak column-strong beam, in the existing structures, there is a need for seismic upgrading of the connection. There are several ways for seismic upgrading of this type of connections.In this research, using steel plates for seismic upgrading of Concrete Beam-Column connections subjected to axial and cyclic loads has... 

Khorjini connection is a type of connection in steel frames, in which the beam remains continuous at the intersection with column. In its ordinary form, this beam is connected to the face of column section using upper and lower angles. This type of connection is frequently used in construction of steel frames in Iran due to economic advantages and ease of fabrication. However since it is rarely used in other countries, its behavior and method of design is not described in international references and standards. The failure of the connections is a dominant type of seismic fraction in a building (The main reason of structural failures in Manjil and Roudbar earthquake – 1990). Contrary to the... 

Double angle connections, which are welded to the beam web and bolted to the column flange, are usually used to make hinged or semi-hinged connections. Several models are presented in this study whose geometrical properties are different. The finite element software package is used to develop the finite element analysis of the connections. An analytical method is presented that can be used to determine the behavior and deformation for this type of connection. The correctness of Moment-rotation curves of finite element analysis for each connection has been ascertained by comparison, using analytical technique; and a very good agreement has been obtained  

Performance of reinforced concrete frames is highly dependent on detailing of the joint connections between its members, such as beams and columns. To have a good structural behavior, joints must show ductile behavior and designed based on the philosophy of strong column-weak beam. In the case of sever lacking ductility, strength or even rigidity of the connections, or having a weak column-strong beam, in the existing structures, there is a need for seismic upgrading of the connection. There are several ways for seismic upgrading of this type of connections.In the last decade Fiber Reinforced Polymer (FRP) widely has been used to strengthening the reinforced concrete (RC) members. Most of... 

Northridge earthquake in 1994 which damaged over 200 connections in moment resisting frames showed improper performance of regular connections. After this earthquake, diverse investigations have been started to clarify reasons of these failures and surveying new methods for their rehabilitation. Behavior of beam to column connections can be improved by shifting the location of inelasticity away from column’s face. Such connections can be achieved by reducing flange area of beams at a specific distance from column’s face, and they have been approved by various design codes. Another kind of these connections can be achieved by perforating beam’s web. Research on latter case shows that, if... 

This thesis presents the development of a Finite Element Model (FEM) for a new type of Beam-Column Semi-Rigid steel connection. This connection consists of a steel semi cylinder connected to a plate and inserted on the top and bottom of the beam connecting it to the column by welding. It seems that changing the geometry of the semi cylinders and their weld lengths can have a great influence on the rigidity or flexibility of the connection. Therefore, meaningful categories of the connection with different semi cylinder geometries and weld lengths have been modeled and investigated by means of a Finite Element Modeling software ABAQUS, and their moment-rotation curves were driven. Also the... 

After the 1994 Northridge earthquake when investigations show clear results for brittle failure near Beam-Column rigid Connections, research on these connections begun and various theories were suggested for better performance under cyclic loads. One of the appropriate ways is shifting yield beam location from beam-column connection to the beams only. Reducing the capacity of the beam through the beam flange or web far enough from the column, creating special ductile region in the beam. In this thesis, weakening is made by creating an elliptical opening in web beams. If the correct design criteria for this type of connection are suggested, it can satisfy the "weak beam - strong column" and... 

Fire is one of the permanent threats due to earthquakes, however in spite of the attention drawn towards design and retrofitting of structures in recent years in our country, no effective steps have been taken for examining design methods and control of the structures’ reactions in case of a fire. One of the reasons for this, is lack of observations and data and also lack of a standard for design of structures that are resistant to fire. Since the connections of beams and columns play an important role in performance of the structures, in this research the behavior of a structure having a semi-rigid connection to an end plate has been investigated by performing an experiment on a scaled... 

A significant amount of research in self-consolidating concrete technology is being placed in evaluating the suitability of the material for use in structural applications. However, research is needed to confirm the ability of self-consolidating concrete structural elements to adequately resist vertical and lateral loads. In a reinforced concrete building subjected to earthquake type loading, the beam to column connections constitute one of the critical regions and they must be designed and detailed to dissipate large amounts of energy without a significant loss of stiffness or strength. In the experimental part of this study, four full size interior beam-column subassemblages with 3.0 m... 

Regarding the numerous casualties and financial losses due to intense earthquakes, the ductility is considered of the main importance in addition to stability, stiffness, and strength criteria of the structure’s connections. In order to enhance the seismic behavior of the structures in such severe earthquakes, design codes for steel structures have suggested special types of connections. Among them, bolted end plate connection is considered a conventional type of connection used for creating ductile semi-rigid connection.In this study, in order to simulate the behavior of this joint, a 3-D finite element model is developed in Abaqus software, in which the inelastic behavior of the materials... 

Today steel tubular systems are used more than before, especially in recent years. A difficulty with this type of systems is making beam to column connections using bolts due to no access to holes of bolts from the inside of tube or hollow circular column. Reverse channel connection is devised and introduced to prevail this problem. Access to holes in this connection is from the inside of channel. In this connection, the web of the channel is connected to steel beam using bolts and the two legs of channel is welded to face of tube column.
This type of connection does include some innovations; not too many researchers work on different versions of this connection. This thesis provides an... 

This thesis presents the investigation and development of a Finite Element Model (FEM) for a new type of Beam-Column Semi-Rigid steel connection. One of the main parts of this connection is a steel T profile inserted on top of a beam connecting it to a column by bolts. It seems that changes in the geometry of the T profile and its bolt positions can have a great influence on the rigidity or flexibility of the connection. Therefore, meaningful categories of the T profile geometry with different bolt positions have been modeled and analyzed by means of a Finite Element Modeling software ABAQUS, and their moment-rotation curves were driven. Also the Initial and Nonlinear Stiffness and the... 

Reduced beam section connection was one of the connections that were introduced and prequalified by SAC project to replace pre-northridge connections. This connection reduces both flanges of the beam at appropriate distances from beam to column connection to make a fuse protecting welds from brittle fracture. The RBS is prequalified in limited span-to-depth ratio, for designing this connection for short and deep beams may effect its performance. Since these limitations are based on limited experiments, forty three numerical models were analysed to recheck them in this study. These models are verified based on two published experiments and are capable of predicting all known yield mechanisms...