Sharif Digital Repository

This investigation is intended to assess the behavior of SCBFs in the presence of typical brace members, which buckles in compression, and BRBs joining by yielding elements. While braces play a role in providing stiffness for structure, central yielding elements will act as energy-absorbing fuses. In this frame type, energy dissipation will mainly be undertaken by BRBs and yielding elements. The mentioned yielding elements do this by initiating plastic hinges in each corner of the central frame. As it is clear, designing a structure that includes the stated lateral-load-resisting system necessitates seismic performance parameters to be evaluated. Hence, by pursuing the FEMA P695 methodology,... 

Incremental Dynamic Analysis (IDA) is a parametric analysis method that has recently emerged in several different forms to estimate more thoroughly structural performance under seismic loads. Using IDA , the objective is to study the effect of the irregular distribution of stiffness and strength along the height of a 9 story 3D steel structure model. The reference and each modified structure are hence forced to show the complete spectrum of behavior from elasticity to final global instability, allowing the estimation of capacities for the full range of limit-states and enabling a straightforward comparison without needing to “tune” the structures to the same fundamental period and/or the... 

A new eccentrically braced system is discussed. In this system which Named “eccentrically braced frame with vertical link”, the braces is connected to vertical link, instead of floor beam. The vertical link acts as a ductile energy-dissipating element, allowing the rest of the construction such as floor beams, braces and columns remain in the elastic range. In this paper, a parametric study is performed on sample frames with push-over analysis. In these analysis, the efficacy of the variation of link length, link area and the position of the link beam, is studied. The results showed that, the most important effective parameters in improvement of inelastic behavior of frame is decreasing of... 

In steel structured buildings the connection of columns to foundations is of practical significance. This connection customarily is performed by a base plate, which is connected to the foundation with bolts. The columns and base plates are usually prepared separately, and later are welded together by contractors. Due to the errors in the process of fabrication, these plates are proposed with larger dimensions than those suggested by the designers. However, it is believed that the utilization of stiffeners, which are welded to the columns in a perpendicular state, reduces the stress field inside the base plates significantly. Therefore, by use of stiffeners the thickness of base plates can be... 

Nowadays, the knee bracing system (KBF) takes civil engineer’s attention because of its benefits and properties. This new form of framing is constructed through the knee and the diagonal brace elements. The knee part is a fuse-like component that dissipates energy by the formation of plastic flexural and/or shear hinge, when the building is subjected to severe lateral loads. In this system, the diagonal brace provides most of the lateral stiffness. Also the flexural or shear yielding of the knee element provides the ductility under a severe earthquake. In this way, the damage is concentrated in a secondary member, which can be easily repaired at minimum cost. Floor distortions are reduced... 

New CKB system is implemented into the multistory frames and investigated how its ductility and energy absorption will be changed if its bracings are able to buckle.buckling braces can improve energy absorption of lateral systems with their post-buckling characteristics through cyclic motions of frames.in proceeding,Nonlinear behavior of multi-story CKB systems within a non-dimensional desigh graphs is presented.application of multi-linear behavior of these systems are controlled by checking their ductility demands and their capacity. Nonlinear dynamic response of multi-story CKB system is analyzed through FEM softwares and presente through curves with which designers can calculate... 

All buildings should be designed to bear both gravity loads and lateral loads such as earthquake. Resisting system for earthquake can be moment resisting frame, shear wall, brace or combination of them. Normally for strengthening of reinforce concrete buildings, shear wall should be added, but in some cases after constructing RC buildings, engineers find out that building does not have enough strength against seismic loads. In this case, adding shear wall is difficult because of architectural restrictions and assembling braces on the original frame is easier.
Structural engineers always looking to find a structural element to absorb earthquake energy to prevent potential damages of other... 

Estimating the nonlinear behavior of sturctures, always have been one of the main concerns of civil engineers. One of the most recent methods for estimating behavior of structures is MIDA technique. It is a procedure that in some levels, substituted for IDA. Although this method presents the approximate results, high accuracy, fastness and inexpensive procedure made this manner to an efficient method. Indeed, this method has been presented to be exerted instead of exact IDA method which is too complicated and prolix. Up to now, no one has used this method for structures incorporating soil-structure interaction. In theMIDA manner, there is no dynamic analysis of ... 

The Steel shear wall is one of resisting lateral load system which has been used since 1970.with respect to design we can apply this system with or without stiffeners .here our investigation is about steel shear wall without stiffeners. Also this system is called SSW. Since using this system is new fashion, there is no specific code for it in Iranian 2800 code .also there is no code for using this system in reinforced concrete frames in any code which makes this investigation much harder. Need to obtain R which is one of the most important seismic parameters, encouraged us to consider R for SSW in 3 to 7 storey structures .we obtained static pushover curves with nonlinear static analysis... 

The behavior of a beam under moving mass has been always interested in the dynamic of structures. In this study, the dynamic response of beam and plate with general boundary conditions under moving mass were investigated using the Dynamic Green Function. Since the majority of previous studies did not consider the Coriolis acceleration, therefore, this acceleration was used in the present study. Boundary conditions are modeled by the rotational and translational restraint. By moving close to the spring constants of the rotational and translational restraint to extreme values (zero and/or infinity), the boundary conditions can be attained for the desired combinations of end boundary conditions... 

The widespread usage of corrugated steel plates as girders and steel shear walls necessitates the need for further investigation of theseefficient structural members. Having significant initial stiffness, high capability of energy dissipation and special geometry are the fundamental reasons for this study. The nonlinear behavior of trapezoidal corrugated steel shear walls with rectangular opening has been studied in this thesis. A series of corrugated and simple shear walls with and without opening regarding different angles of corrugation and different infill plat thicknesses have been investigated. This analytical study was conducted to compare the initial stiffness, ultimate strength,... 

This study investigates the cyclic experimental behavior of damaged exterior reinforced concrete beam–column joint specimens retrofitted with the proposed technique using steel elements called steel prop and curb. The technique is usable for local and global strengthening of reinforced concrete frames. Four half-scale RC joints were tested under the cyclic loading; two control specimens with the different beam heights were loaded up to their ultimate strength and this was followed by retrofitting of these damaged specimens as new specimens and tested again under the same loading system. This study indicate the importance of some parameters such as friction , jacket place , thickness of plate... 

This study is devoted to the analysis and design of a recently proposed steel-FRP deck system. A methodology is being proposed to analysis the elastic behavior of the proposed deck. In this method the deck is modeled as an equivalent orthotropic plate which is constrained by rotational springs along its edges. An analytical model of the proposed deck is derived by using Rayleigh-Ritz method where the primary Rayleigh-Ritz shape functions are generated from orthonormal polynomials by using Gram-Schmidt procedure. The results of the proposed methodology show good agreement with finite element analysis results. In order to test the applicability of the proposed deck as buildings flooring... 

Plan irregularities of structures due to the governing regional and environmental conditions are a pretty important issue from the architectural as well as structural design point of view. Most of the time, especially in mid-rise and/or high-rise buildings with plan irregularities, dual system of Moment Resisting Frames (MRF), accompanied with shear walls are strongly suggested. Considering the previous works and investigations of researchers, reveals not too many studies and researches in this regards; specially, when it comes into new area and application of the Steel Shear Walls (SSW). In the present work, at first it is proposed to model and analyze a MRF steel structure with plan... 

Nowadays, according to increasing development of construction industry in the world especially in the building area, the need to use technology and innovation for fabrication and maintenance of this industry has increased. And this fact becomes apparent that the use of traditional systems of construction isn’t tailored the countries’ requirements anymore. One of the construction industry’s limitations is the restrictions on architectural designs reys. The columns are among the most important components of structure and have a major role in bearing all gravity and lateral loads and transferring them to the foundation. The failure or destruction of the components in the structure under applied... 

The method of nonlinear time history analysis is well known as one of the most accurate techniques in seismic analysis of structures. However, this method needs much effort in terms of required data and computational cost. Within the time constrains of design consulting firms, more simple analysis tools are also desirable. One of the simple methods which have been gaining ground, as an alternative to time history analysis, is nonlinear static pushover analysis. In this method, the capacity curve of the structure with respect to the roof displacement is established. In nonlinear static pushover analysis, disproportionate increases in the roof displacement and even outright reversals the... 

In this article a new structural bracing system is discussed. In this framing system, a special form of diagonal braces, that connected to the knee elements instead of beam-column joints, is investigated. The diagonal elements provide lateral stiffness during moderate earthquakes. However the knee elements is designed to have one plastic joints in yielding of knee elements for dissipation of the energy caused by strong earthquake. First by elastic studying of the system and establishment of new and practical parameters, a suitable shape for brace and knee elements is proposed. Then by development of applicable and very well accuracy models in Drain-2DX , the inelastic behavior of the... 

The study of bolted moment end-plate connections, both beam to column and beam to beam connections, is quite general and standard nowadays. Buildings which utilize such connections are widely being used and the reorganization of their significant benefits is growing. The research work reported in this thesis presents the results of several parametric analyses to determine the moment–rotation curve of bolted moment end-plate connections utilizing Rectangular Hollow Sections (RHS) and two rows of bolts using Finite Element Modeling (FEM). Previous experimental studies have focused on the moment-rotation relationship under pure bending. This project particularly involves further numerical... 

Dynamic response of structures, against ground motion, is one of the most important issues in earthquake engineering. A variety of approaches and apparatus have been developed for this purpose. One of these equipments is metallic dampers. Such apparatuses provide damping, accompanied with reasonably strong lateral stiffness; hence, they are named as “Added Damping And Stiffness” (ADAS). The present study aims to evaluate the performance of a common metal damper consisted of triangular metal plates known as “Triangular Added Damping And Stiffness” (TADAS). In this investigation, the performance of TADAS, in an eight story irregular in plan steel structure, is extensively considered. A 3-D...