Sharif Digital Repository

As you know, the behavior factor is one of the important parameters and values for calculating earthquake force and base cutting in the building. In this research, the effect of coefficient of behavior (R) on metal structures has been investigated. For this purpose, we selected a metal structure with an average bending frame and dual system with shear wall and examined it. To determining the effect of this coefficient on different structures, we modeled the structures with regular and irregular plans. Considering the structure height effect and also the type of soil on the site of the proposed structure to the factor and refractive coefficient (B) and its direct impact on the magnitude of... 

Assessment of the probability of collapse or exceeding other limit states is one of the major goals of Performance-Based Earthquake Engineering. Moreover, other beneficial materials such as estimation of loss of money and downtime, which make it convenient for decision makers to judge the condition of a structure and take wise steps about it, can be drawn from the results of such an assessment.Current work investigates the probability of collapse and also immediate occupancy limit states at three discrete hazard levels of 50%, 10% and 2% in 50 years and also by utilizing mean annual frequency approach for three archetypes of steel special moment-resisting frames of 4, 8 and 12 stories.Ten... 

Composite Reinforced Concrete-Steel (RCS) frames which have reinforced concrete columns and steel beams attracted a lot of attention in recent years. They take advantage from the benefits of both reinforced concrete and steel frames thorough using the optimum combination of concrete and steel structural elements. In this research six structures including three 3-story, and three 6-story buildings are designed in a region with very high seismicity risk. These structures include composite RCS moment frames, special steel moment frames, and reinforced concrete special moment frames. RCS moment frames which are designed they not only have reinforced concrete columns similar to reinforced... 

Assessing the seismic loss incurred by structures post-earthquake, or to evaluate structural performance vis-à-vis potential seismic events, constitutes an imperative and pivotal measure for informed decision-making geared towards enhancing community resilience. However, large-scale assessments targeting risk analysis at citywide levels necessitate significant temporal and computational resources. To expedite this process and mitigate associated costs, this study introduces a machine learning-based methodology for estimating seismic loss and repair time of special steel moment-resisting frames. Six distinct machine learning models were trained based on results derived from nonlinear time... 

The purpose of this study is to investigate the effect of consecutive earthquakes by considering different levels of structural damage intensity index. The cumulative damage of structures caused by the sequence of main earthquake and aftershock is a combination of the initial damage caused by the main earthquake and the increased damage caused by the aftershock. The evaluation process of the main earthquake and aftershock is divided into two parts: evaluation of the fragility of the main earthquake and evaluation of the fragility due to the aftershock. This investigation was carried out using a 4-story steel building with special moment resisting frame. The results for the case of only the... 

The sustainability of urban infrastructure is assessed in three integral economic, social, and environmental dimensions. This study focuses on advancing a design approach based on value through the optimization of the life-cycle cost of steel moment frames, considering sustainability indicators by utilizing endurance time method analysis.In this path, the dimensional specifications of steel frame sections are selected optimally using an automated process with the objective of minimizing the cost of the structure's life cycle as the objective function and code specifications as optimization constraints. The cost of the life cycle, includes material extraction and production, transportation,... 

Seismic base isolation is the most effective method of protecting and strengthening structures against seismic damage caused by large to small earthquakes and aftershocks. Providing damping and energy absorption of the seismic isolation at the structure's base level can significantly reduce the cost of repairing and strengthening the structure in addition to reducing seismic damage. However, besides these advantages, due to their high cost, seismic isolations in major infrastructure projects, hospitals, and crisis management centers should have economic and social justification. In this regard, a value-based seismic design approach can justify this important issue. In recent years of... 

Vertical addition of existing buildings provides more living space without the need for more land use. Also adding a story on an existing building is one of the common needs in metropolitans. However, the structure may bear high risk due to vertical addition. This study aims to model conventional concrete structures built in Tehran and then assess and compare the seismic performance of base structure and extended structure. Seismic performance of a system is defined as their efficiency in providing enough safety and reducing the Life-Cycle Cost. For this purpose, seven archetypes as base structures and eight extended structures corresponding to base structures, that had residential... 

Nowadays, using perimeter steel moment frames in combination with interior gravity frames have become common practice in structural building design. One of the key benefits of this system is the open space that it provides for the architects. In active seismic regions, special details are required in the design of the seismic force resisting systems to make these frames ductile. However, these details cause excessive displacement for the gravity force resisting system. Although the gravity frames are not designed to endure seismic forces, they collaborate in the system’s response as they are connected to the same floor diaphragm and withstand lateral displacements. Therefore, these systems... 

Most of the seismic regulations in the Iranian design codes are adopted from the U.S. codes, while the severe earthquake rates with regards to the gross area and total population of Iran is 8.4 and 5.5 times the rates for U.S. respectively. In fact, Iranian rates are between the ones for U.S. and Japan which have up to 200% difference in prescribed strength level in their seismic codes. Poor construction quality regarding defected control in Iran adds to the problem. Therefore, the prescribed strength level of U.S. building codes and thus their target reliability index seems insufficient for use in Iran. Also, previous research has shown that the load and resistance factors in Iranian... 

This paper proposes a novel probabilistic approach to account for soil-structure interaction (SSI) in the seismic design of building structures. In this approach, an SSI response modification factor, RSSI, is introduced to capture SSI effects on the seismic performance of structures. The proposed procedure quantifies RSSI such that the probability distribution of the collapse capacity of the structure designed to account for SSI concurs with that of the structure designed using the default fixed-base provisions. The proposed approach is employed for special steel moment frame buildings with surface foundation. A surrogate single degree of freedom (SDOF) system is developed in this study and... 

Modified Fish-Bone (MFB) Model and Consistent Generic (CG) Model are simplified Multi-Degrees-of-Freedom (MDOF) models, proven to be valuable tools in estimating seismic demands of moment-resisting frames, aimed to reduce the computational costs by decreasing the number of degrees of freedom. The preliminary expansion of these simplified models for steel moment resisting frames (SMRFs) were proposed by considering elastoplastic behavior and is not able to take into account stiffness and strength deteriorations in nonlinear dynamic behavior of structures. However, behavior deterioration affects seismic demands of SMRFs under intense earthquakes. For this reason, the present study is done to... 

Regarding available structural codes, for designing of buildings with dual lateral force resisting system which includes special moment frames and ordinary concentrically braced frames, we need to determine seismic performance factors. Seismic performance factors embraces of response modification (R), over strength (Ω0) and displacement amplification (Cd) factors. The goal of this research is to evaluate aforementioned factors using the method presented with FEMA P-695. This method represents a reliable framework to assess the seismic performance factors of various kinds of lateral force resisting systems. In this approach, first, archetypes are designed with assuming certain values for... 

The purpose of this research is to investigate the seismic behavior of plane moment resisting frame consisting of steel-concrete columns and steel I beams utilizing fragility curves. Due to the great influence of the column type in seismic performance of structure. To reach an optimal system, different types of steel-concrete composite columns has been used in the models and the fragility curve of each one is compared. Steel-Concrete composite columns can be divided into three types: (1) concrete filled steel tube (CFT), (2) steel reinforced concrete (SRC) and (3) new combinations of (1) and (2). Due to the abundance of the use of concrete filled steel tube (CFT) and steel reinforced... 

In many structures, using long span girders due to architectural reasons is evitable. Studies show that in this situations, using plate girders is not only a non-economical choice, but also it reduces the structure performance, because of plastic hinges which would be formed in columns instead of beams, due to higher stiffness of girders. To overcome this difficulties, Truss girders or open-web ones are good choices for substitution. Recently, a novel lateral loading system named “truss bending moment system” equipped with buckling restrained braces (BRB) is also proposed. In this research, some structures with usual configurations are designed with both mentioned systems. In each case,... 

In this thesis behavior of intermediate steel moment frames and intermediate steel moment frames equipped with knee element are investigated. The knee element attaches to the beam element by inverted-V type concentric braces. The knee element acts as a fuse to dissipate input energy during an earthquake by the formation of plastic hinges. On the other hand, brace elements remain in the elastic range without buckling and provide suitable lateral stiffness. Main object of this investigation is reducing deteriorations in the main frame in intermediate and sever earthquake by concentrating deteriorations in knee element. Whereas knee element is not a main element of the frame, retrofitting of the... 

In past few decades researchers and engineers have researched extensively on the effects of masonry infill walls in structural frames and the effects of masonry infill walls on the structural response was a concern for them. Since used materials and therefore the strength and stiffness of these walls are extremely depends on construction site and available mate-rials, according to geographical conditions most of countries inserted their own rules for considering effects of masonry infill walls in their codes and standards. Our country, Iran was not excepted from this regularity and in past few years the effect of existence of ma-sonry infill walls in structural response has been considered...