Sharif Digital Repository

Seismic design codes reduce loads by using response modification factor. Because of the reserved strength in structural elements and capacity of structure to dissipate energy, structures can be designed for lower seismic loads. This factor has modified over time. In this thesis, the effect of the reduction in behavior factor on the response of two kinds of reinforced concrete systems were evaluated. Moment resisting frames and dual systems with different heights and regularity in plan, heve been design according to the behavior factor which is recommended in the 3rd edition of the Iranian codes of practice for seismic resistance design of buildings (Standard No. 2800). Drift and... 

Because of absence of adequate studies, design of deep beams with web openings has not yet been covered by most codes of practice. The most studies have been on simply supported deep beams with web openings and have been set up experimentally. There are very few tests of continuous deep beams available in the literature. So it was decided in this thesis the behaviour of concrete continuous deep beams with web openings using finite element software ANSYS to be investigated. Primary purpose of this thesis has been evaluating the use of finite element analysis method for analysis of concrete continuous deep beams with web openings. The next target of this thesis has been assessment of... 

Post-tensioning is the most versatile form of prestressing, a technique which enables engineers to make the most effective use of the material properties of concrete, and so to design structural elements which are strong, slender, and efficient. Design of post-tensioned concrete structures is not difficult and, if done properly can contribute significantly to the economy and the aesthetic qualities of a structure. Post-tensioned building floors and bridge girders have found widespread use in office buildings, parking structures and bridges. They are also frequently employed in warehouses and public buildings. Now a days bridges and other type of structures, in many countries are designed... 

Wall-Frame interaction under lateral load has been considered in studies, and it is concluded that interaction lateral forces of rigid frame and shear wall varies at different stories. This is resulted from of different mode shape of rigid frame and shear wall under lateral loads which are shear and bending mode, respectively. However most codes recommend a minimum strength for frame, equal to 25% of total lateral force, as an acceptance criterion of shear wall-frame dual action; otherwise this minimum strength does not fully comply with horizontal distribution of lateral load according to relative stiffness of components.The purpose of this article is to study nonlinear seismic response of... 

Due to the growth of population and the increasing number of auto-manufacturing plants in the world, governments have to find ways to decrease traffic, environmental pollution, etc. Providing parking lots is another problem with which we have to deal. It seems that designing and building multi-storey reinforced concrete parking structures is one of the ways to resolve this problem. According to complex behavior of concrete in compression and tension, it was so important to use an appropriate behavior model. In this research damage concept is used instead of crack concept which could models concrete behavior appropriately which causes acceptable results. According to uni-axial, bi-axial and... 

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... 

In tall buildings, seismic behavior depends on structural elements and their configuration. The usefulness of shear walls in the structural planning of multistory buildings has long been recognized. When walls are situated in advantageous positions in a building, they can be very efficient in resisting lateral loads originating from wind or earthquakes. Restriction in surrounding effects and the architectural design may contribute to have asymmetry in plan. In a number of papers, published mainly in the last decade, the analysis and design of shear walls has been studied. But just a few of them considered arrangement of shear walls to find the optimum layout. In the present study, analysis... 

In recent years, the use of fiber reinforced polymer (FRP) jackets, as an external lateral confinement has found considerable attention in retrofitting and strengthening existing reinforced concrete (RC) columns in earthquake prone areas. The FRP composites have numerous advantages such as ease in application, high strength and stiffness-weight ratio, no corrosion and negligible changes in the member dimension. Most of previous studies have concentrated on evaluation of the effect of confinement with spiral bars or FRP composites, separately. However, in practice both types of confinements exist in strengthening RC columns.
This paper presents the results of a computational modeling to... 

According to key importance of bridges in transportation system vital routes, a need to study and survey of bridges against destructive factors exist. Among these, bridges with concrete deck are widely used. One of the most important factors in destruction of these bridges is steel reinforcements corrosion and destruction of bridge deck. So in order to reduce the aggregation of reinforcements in critical sections and performance improvement of deck beams, a reinforcing substance which is not only resistant against corrosion but benefits from high resistance and stiffness is implemented.In this research the case studied bridge is simulated by finite elements software in two cases; reinforced... 

The experience from the performance of buildings during past earthquakes has shown that asymmetric buildings often sustain more extensive damages as compared to the symmetric buildings. The rules of seismic design codes about these buildings are based on investigation of single story buildings in the elastic range and they use rigidity eccentricity as main irregularity criterion. Inasmuch as during damaging earthquakes some lateral force resisting elements will not remain elastic and they reach yield, rigidity eccentricity will no longer be an appropriate parameter to represent the asymmetry of structure; thereby, in these building all centers of mass, rigidity, and strength should be paid... 

Tunnel form structures have been proposed in building industry during 40 years for financial saving, suitable structural performance and seismic behavior, and the possibility of performance in an industrial form; and they have also been brought up as one of the innovative technologies of construction in Iran for a couple of years. So far, these structures have been subject to study by the researchers less than frame structures. In comparison to the common structures, evaluating the behavior of these structures is analyzable as two or three-dimensional elements. In this research, the nonlinear behavior of these structures has been simulated and evaluated by using three-dimensional elements;... 

In recent years, more attention has been paid to the development of lightweight concrete (LWC). Study of such this material had been marked due to more importance of use of it.It is now well known that in order to model cracks the finite element model is more suitable.The fracture of quasi-brittle material such as concreteincludesthe fracture process zone (FPZ).Cohesive zone model is considered the most common model used for FPZ modeling.Therefore, in this article the propagation of cohesive cracks inLWC is modeled using the extended finite element method (XFEM). In this study, modeling showed fastgrowth and propagation of cracks inLWC. Due to its cavities and pores, LWC shows to be more... 

concrete-filled steel tube offers many practical advantagescompared withconventional structural systems. The concrete infill provides stiffness and strength in compression and restrains local and global buckling. The inelastic deformation capacity of the CFT system is increased by the confinement of the concrete fill by the thin, ductile steel tube, and this significantly contributes to the seismic performance.
In this research, Formation and development of plastic hinges in CFST frames using pushover analysis was investigated. Different frames with rectangular and circular column and I beam weredesigned and Using nonlinear finite element analysis, interaction between steel and concrete... 

Reinforced concrete (RC) column in building often needs strengthening either due to defects in the column themselves, having to support higher loads than those foreseen in the initial design of the structure or as the result of ageing or accidental damage such as earthquake force. The use of FRP wrapping, steel caging or reinforce concrete jacketing for this purpose is now a common practice in many countries throughout the world. Even though a considerable number of researches have been conducted on retrofitting methods during past years, but very limited researches have been done to compare these methods. This research has investigated the effect of jacketing from different views. The... 

Modeling is one of the most important steps in analysis and design of structures. Most of the time behavior of floor diaphragms is assumed completely rigid in their plane in order to simplicity in practical design. Although this assumption leads to acceptable results in analysis and design of conventional buildings, erroneous results may assess in some particular buildings—for instance narrow buildings with stiff end walls. Accordingly, behavior of these buildings in future earthquakes opposes those were predicted in design phase, and they are so vulnerable since in-plane deflection of floor diaphragms are striking which cannot be ignored. This thesis investigates the significance of... 

In recent years, in order to investigate the structural performance in seismic zones, concrete column reinforcement and observing their behavior under cyclic loading have attracted considerable attentions. The ductility and energy absorption capability of structure play an important role in structural performance against earthquake and consequently its failure patterns. A new chapter of these investigations has begun by the reinforcement of the concrete members, a major part of which is concerned with the confinement of concrete members in order to increase their ductility and energy absorption against the forces induced by earthquake. In this study, three prominent methods of concrete... 

The main problem of steel-reinforced concrete structures is corrosion of steel reinforcements which leads to premature failure of the concrete structures. This problem costs a lot annually to rehabilitate and repair these structures. In order to improve the longterm performance of reinforced concrete structures and for preventing this corrosion problem, Fiber Reinforced Polymer (FRP) bars can be substituted of conventional steel bars for reinforcing concrete structures. This study is a numerical study to evaluate structural behavior of the simply supported concrete beams reinforced with FRP bars in comparison with steel-reinforced concrete beams. The commercial Finite Element Modeling... 

Concrete filled double-steel-plate (CFDSP) composite wall is a new lateral resisting system that recently used in design and strengthening of high-rise buildings. This CFDSP composite wall is composed of concrete filled steel tubular columns at the two boundaries and concrete filled double-steel-plate wall body. The main advantage of this system is the interaction between steel and concrete which delays local buckling of steel plates. Also, steel jacket increases the strength of concrete in result of confinement effects. Furthermore, these systems have lower thickness compared to ordinary concrete shear walls. Hence, they have less structural weight which reduces the earthquake force.... 

There is a requirement for strengthening of steel structures due to undesirable design, wrong implementation, bad maintenance and changes in design codes. Many studies have been done on strengthening of concrete specimens but there is a need for reinforcement of steel specimens yet. In the present paper, results of an experimental study on strengthening and reinforcing of steel beams under mechanical loads have been presented. Totally, Sixteen steel specimens with span’s lengths of 0.2, 0.5 and 1 meter were reinforced by carbon laminates and subjected to -point bending load. Three failure modes of shear yielding, flexural yielding and lateral_torsional buckling in the beams were examined.... 

Increasing the population of cities has led to the more construction of high-rise buildings. In design of high-rise buildings, stability of structure plays a significant role in its final design.According to the fourth edition of 2800 standard (The Iranian code of practice for seismic resistant design of buildings), for buildings with height of more than 50 meters, only using dual system and special moment resisting frame system is allowed, whose stability condition will increase the final cost of the structure. Systems such as outrigger system have been created to overcome this weakness. Outrigger is a rigid, horizontal system that is perpendicular to the shear core and connects the shear...