فهرست مطالب محسن علی شایانفر

Bridges have a special place in transportation infrastructure due to their direct connection with other places. These structures aim to carry highway traffic loads, pass any obstacle and establish effective communication between two destinations. Damages caused by earthquakes and human factors cause very serious damage to bridges, and if even the failure of a member does not cause the structure to collapse completely, the cost of retrofitting is very high. For this purpose, researchers and engineers suggested the use of structural control systems along with accurate seismic analysis to predict the behavior of the structure. The purpose of this study is to investigate the displacement in bridges using multiple tuned mass dampers in parallel and series mode. The effects of damper modeling on Meloland overpass bridge are investigated for the first time with the help of the proposed method in this article. In this research, the bridge structure presented by Vahid Shirgir et al. is used as a sample structure to investigate the issues raised with Opensees software. This bridge is designed by taking into account the regulations, gravity and dynamic loads, and its structural specifications include dimensions, type of materials used based on the article of Vahid Shirgir et al. Finally, it was found that the multiple tuned mass damper in parallel mode has a better performance in reducing the maximum displacement than other tuned mass dampers. Also, according to the results, the response of the structure equipped with multiple tuned mass dampers decreased by 21% and improved the seismic performance level of the bridge column.

Corrosion is one of the crucial damages that may occur to reinforced concrete structures. It also may affect the expected performance of the structure during the possible earthquakes. Onshore reinforced structures, bridges exposed to deicing salts in winter and also the pillars of marine structures under tidal waves, all of which are examples of corrosion damages. Corrosion mostly occurs due to two main reasons: chloride and carbonation which cause pitting corrosion and uniform corrosion, respectively. Corrosion starts with reaching of those two ions to the bar surface, passing by the physical and chemical passive covers. Corrosion also affects the mechanical properties of the steel and the concrete and reduces the seismic performance of the structure. One of the most important parameters in studying the corrosion and its effects on the seismic performance and life cycle of the structure is the corrosion initiation time. According to Fick’s law, the initiation time is a function of surface and critical chloride, chloride diffusion coefficient and concrete cover on armatures. In the present study, the chloride-based corrosion is considered. Besides, corrosion initiation time is determined by deterministic and probabilistic Monte-Carlo methods considering the uncertainties in the effective parameters. In the end, by comparing these two methods, the effect of uncertainties in the possibility of corrosion initiation time is presented. Furthermore, parameters like the distance from the sea and the water to cement ratio are discussed in a parametric study.

Today, the construction industry has a significant share of the economy and is considered as a leading and employment-generating industry. Due to various and sometimes risky activities during construction, there is a possibility of risks and personal and financial injuries, the control of which can be very effective in the success of the project. In the present study, a model for evaluating the safety risks of construction projects has been presented and new powerful tools such as fuzzy expert system improved with genetic algorithm have been used. Therefore, at first, the main factors influencing the safety of construction projects were identified by studying the literature and consulting with experts. Then, a questionnaire was provided to the experts to obtain their views and assess the severity of the risk effect and the probability of the occurrence of each risk. Then, based on the experts’ views, an expert system was obtained to assess the risks, which instead of using zero and one logic, governing expert systems, fuzzy logic was used. In the proposed model, to improve the performance of the fuzzy expert system, the genetic algorithm was employed as an optimizer. The research results indicated the optimal performance of the proposed model in assessing the safety risks of construction projects, so that the error rate of the model was acceptable. The model can also provide an effective tool for project managers in assessing and refining the safety situation in the construction site.

Corrosion of steel reinforcement in concrete structures is one of the most influencing factors in the loss of durability of reinforced concrete (RC) structures. Neglecting the effects of corrosion has unpleasant consequences and may lead to the failure of structures before their designed life time. Corrosion reduces the cross section of the steel reinforcement, changes the mechanical properties of the steel, decreases the strength of the concrete, and ultimately reduces the capacity and ductility of RC structures. In this study, the effects of corrosion on the moment-curve diagram of structural elements are studied and then compared with the approaches recommended by guidelines such as FEMA-356. To evaluate the effect of steel corrosion on the performance of structures, two RC frames (3-storey and 7-storey) are modeled and two corrosion scenarios are applied to beams and columns of the structures. Then, capacity curves of structures as well as design parameters such as ductility coefficients are obtained by nonlinear static (pushover) analysis of the structures considering the effects of corrosion on moment-curvature diagrams of structural elements. The results show that the coefficient of awareness of 0.75 according to the guidelines such as FEMA-356 can lead to overestimate the structural capacity in highly corrosive environment. It also leads to conservative and uneconomic results in a low corrosive environment. It is observed that the capacities of the 3 and 7-storey structures have been decreased between 19 to 36 percent due to corrosion. Results also show that corrosion reduces the structural capacity between 8 to 28 percent.

Nowadays, designing structures follows the designs that are based on the performance. Regarding the structures, designing based on performance requires dynamic, heavy and repetitive analyses. Endurance time method is a dynamic modern method based on the performance of the structure, which leads to the reduction of number of structural analyses. In this method, the structure gets exposed to increasing acceleration functions that is getting more during time and then the structure`s seismic performance is evaluated using various demand parameters. In this article, though, using endurance time method, the performance of a structure having active mass damper was evaluated under endurance time acceleration functions of ETA20e series. To this end, an 11 story structure having active mass damper was modeled in MATLAB software using one of the fuzzy control methods. Having investigated the results of endurance time diagram that had drew the before and after statuses of the refinement process using active mass damper, the efficiency of this system in reducing the interstory drift and maximum final story drift was explored. Moreover, the results of endurance time under acceleration function of ETA20e series were compared with the time history analysis of 7 selected accelerograms. The results indicated that endurance time function could present an appropriate prediction in estimating the behavior of the structure under selected accelerogram. The results indicated the significant impact of adding mass dampers under increasing the endurance time of the building under investigation.

Given that bent steel bending frames are one of the load-resisting systems such as earthquakes and winds, the role of bonding resistance in these frames will be crucial. The purpose of this study was to investigate the behavior of semi-conductive welded steel joints on the seismic behavior of 3D steel frames. The results of this study show that with the decrease in the number of structural classes, in this project the reduced formability of the structures decreases the IDA curves to a lower IM level, indicating that with increasing Structural plasticity can be achieved by higher computations in structures at the same earthquake level. Also, the coating curves corresponding to the structures with less ductility are at a higher level, that is, the coating curve is lower at higher level, with increasing formability in nonlinear static analysis. In other words, with increasing rigidity of the joints, the structures behave more rigidly and their bending curves are higher and the structures with higher plasticity become horizontal at lower seismic intensity levels. And the rigid structures are at a higher level, which is also reflected in the results of nonlinear static analysis, and by decreasing the rigidity of the joints, the effective alternation time of the asymmetric structure increases and the spectral acceleration decreases. Also with decreasing joint rigidity, the contribution of higher modes increased, so in semi-rigid joints the number of effective mods in the structures is higher than the rigid state. This issue can play an important role in the design of the structure. According to the findings of this study, little work can be done to investigate this method in the country, although research on the behavior of welded steel joints has so far been studied.

In structural engineering, it is vital to design structures by providing pre-defined performance objectives economically. Reliability-based design optimization (RBDO) is looking for the best balance between safety and cost, by considering uncertainties in structural parameters and loading conditions. In recent decades, several methods have been used to solve RBDO problem. However, most of these methods suffer from high computational cost of solving the problem as a big challenge.In this paper, weighted simulation method, one of the newest and most effective methods for simulation-based reliability assessment methods, has been used for reliability analysis and evaluation of probabilistic constraints. The advantages of this method are a significant reduction in the computational cost and the proper accuracy of the final results.For minimizing the objective function, which is the weight of structure in this paper, Firefly algorithm (FA) is utilized. The FA is a stochastic metaheuristic approach based on the idealized behavior of the flashing characteristics of fireflies. In FA, the flashing light can be formulated in way that it is associated with the objective function to be minimized. The numerical example results indicate that using the proposed method leads to the optimum design solutions better than other methods in the literature without violating reliability constraints.

As service years increase, the corrosion of steel rebar stands out as a major problem for existing reinforced concrete (RC) structures in corrosion-inducing environment. The mechanism of steel corrosion in concrete is an electro chemical process, which is often accelerated by the ingress of aggressive chemicals, for example chloride ion. The accumulation of corrosion products on steel rebar is able to generate circular stress which could result in cover cracking. Corrosion of steel rebar will degrade the physical appearance and reduce its original cross section. Corrosion often appears to be non-uniform and localized. Corrosion damaged RC elements displayed smaller yield strength, ductility, energy dissipation capacity, etc. Corrosion level of stirrup tends to be higher than longitudinal rebar due to smaller diameter and less cover protection. Stirrup corrosion decreased confinement behaviour on concrete, thus exacerbating the degeneration of the deformation capacity and the ductility of the RC structures. The corrosion of reinforcement steel bars (rebar) is a natural electrochemical reaction RC structures have to face with. It is exacerbated by exposure to corrosion-inducing environment factors, including de-icing salt, marine salty water, carbon dioxide, sulfur dioxide, etc. The chloride from salt (NaCl) could make hazardously chemical attack on steel bar by acting as an efficient catalyst in the corrosion process. The corrosion of steel bar in the existing reinforced concrete structure has raised great concern over its safety and seismic performance among practising engineers, researchers and residents, etc., because steel bar is the most essential element in RC. Corrosion reduces the effective cross-section area of longitudinal and transverse rebars.
Due to a small concrete cover of transverse rebars compared with longitudinal rebars, the corrosion of them becomes earlier and more severe, leading to cracks in concrete, a decrease of confinement, an intensification of reduction in deformation capacity and ductility of reinforced concrete structures. For this purpose, an experimental investigation is carried out on reinforced concrete specimens include spiral and stirrup and the variables include the corrosion percentage, rebar diameter, transverse rebar pitch, and confined core diameter. Results demonstrate that the high degree corrosion has a fewer significant effect on the reduction in confinement strength, and smaller-sized transverse reinforcements are less sensitive to corrosion.

Earthquake ground motions may vary significantly at multiple supports of long structures such as highway bridges and dams, due to the incoherence, wave-passage, and site-response effects. Therefore, it is expected that seismic behavior of this type of structures would be strongly affected by the changes caused by the motion of the earthquake along the length of the structure. To investigate the seismic vulnerability of these bridges, fragility analysis is performed using spatially variable ground motions. To achieve this aim, this study chooses a set of 70 box-girder bridges considering mechanical and geometrical uncertainties and creates a numerical model of the bridges in OpenSEES software, which can account for the inelastic response of its multiple components. These models are assessed using two scenario of applying the ground motion, uniform and multi-support excitation. The results show that the fragility of these bridges increases with decreasing deck radius by more than 50% (depending on damage level and deck radius) and also with non-flexibility considerations, component vulnerability and bridge system more than 10% is more than a uniform excitation.

One of the most concerns about design and maintenance of structures in civil engineering is the safety of structures in the events of natural disasters, including earthquakes, which requires adequate resistance and providing expected performance of structures. Different factors can have an impact on the occurrence of damage and the damage content in structures and, consequently, the loss of economic assets as well as human health and life safety during earthquakes. Normally, high alkaline property of concrete, PH about 13, forms a protective oxide layer on the reinforcement steel surface. The Carbon dioxide in the atmosphere or the chloride ion in the concrete environment especially in the coastal zone, along with the moisture and the oxygen can penetrate through the concrete pores and micro-cracks and can reach the rebar surface. Then, they cause rebar corrosion inside the concrete by destroying the protective oxide layer on the steel surface. Chloride ions reach the passive layer according to the explained pattern and they begin to react in the passive layer when the amount of chloride ions exceed the critical value and cause the perforation corrosion. Therefore, the performance of deteriorating structures can be different from the desirable performance of pristine structures. Corrosion of steel reinforcement in reinforced concrete (RC) structures is one of the main factors in increasing the vulnerability of RC structures. Due to corrosion, mechanical properties of steel involving yield and ultimate stresses, their corresponding strains, and the elasticity modulus of steel will change. Also the cross-sectional area of steel reinforcement decreases. Furthermore, after cracking, the mechanical properties of concrete will change. In this study, in order to investigate the seismic fragility and vulnerability of RC structures due to steel reinforcement corrosion, two buildings involving a 3-storey and a 7-storey RC moment frames are modeled based on the lumped plasticity model for considering nonlinearity. Two corrosion scenarios of 10 and 20 percent reduction of steel reinforcement cross section and their effects applied to the structural members of these RC frames. Then, seismic performance and the fragility of these two RC frames are investigated using nonlinear static analysis (pushover analysis) and incremental dynamic analysis. Fragility analysis results show that the probability of failure and seismic fragility of RC structures increased due to reinforcement corrosion. Therefore, fragility curves shifted to the left due to corrosion, illustrating the increase in the probability of damage at different spectral accelerations. The safety margin of the collapse of the 3 and 7-storey structures also decreased due to corrosion. For example, as a result of 20 percent corrosion scenario, safety margin of three-storey structure decreased by 16.5 percent and the safety margin of seven-story structure decreased by 28 percent. Results also illustrate that the collapse margin ratios of both structures (CMR) are reduced for 10 percent corrosion scenario. Although the probability of failure increased for 3-storey RC frame, it remains below 10 percent. However, for 7-storey RC frame, the probability of failure exceeds 10% (allowable failure probability adopted by the code) and the frame needs to be rehabilitated.

Increasing energy consumption in the world raises concerns about future energy supplies. In addition, reducing energy consumption will reduce greenhouse gas emissions, such as CO2. Given that residential buildings have a significant share in energy consumption, reducing energy consumption in these buildings through the Building Management System (BMS) and insulation of their Exterior walls can have a significant impact on reducing energy consumption.In order to evaluate the impact of these factors on reducing the energy consumption of residential buildings, using Building Information Modeling process (BIM) with the help of BIM software is the method used in the present study. Using building information modeling process, after the modeling of the desired properties, the thermal analysis of the building has been done and by changing the parameters, the effect of each one on the energy consumption is investigated.The main objectives of this research is to investigate the effect of the use of thermal insulating materials and building management system on reducing energy consumption, comparing all types of thermal insulating materials in terms of type and thickness, comparing insulation and building management systems in terms of reducing energy consumption and finding optimal energy-saving model between different building models that have different conditions. Comparison in this study has been done between different building models and the actual base model. Finally, by doing the stated studies, the model with BMS system with 34.61% reduction in energy consumption compared to the base model has the most effect on reducing energy consumption.

Carbon dioxide and carbonation in concrete structures after several years may leads to corrosion of the reinforcements, and consequently reduces the life of concrete structures. According to reports of IPCC, uncertainty to predict the weather conditions is very high. The annual growth rate of carbon dioxide concentrations from 1.4 ppm during the period of 1960 to 2005 has increased to 1.9 ppm during the period of 1995 to 2005. Two predictions of A1F1 and A1B are presented for changes in carbon dioxide concentrations. In A1F1 high economic growth, population growth will continue in the mid-21st century with high speed, and the use of fossil fuels will also continue as before. In A1B, using clean energies is common. In fact, A1F1 and A1B are respectively pessimistic and optimistic predictions for the concentration of carbon dioxide in the environment. According the analysis results base on Monte Carlo simulation, global warming and climate change lead to an increase in average temperature of Earth and atmospheric carbon dioxide concentrations, and finally, it can reduce the durability of concrete structures. Also, it was observed that ignoring changes in concentration of carbon dioxide can have a significant effect on the results obtained for carbonation depth. It was also observed that considering each of predictions for changes in carbon dioxide concentrations does not substantially influence the depth of carbonation.

In recent years, evaluation of deterioration and aging effects on seismic performance assessment of existing reinforced concrete structures has been paid much attention in earthquake and structural engineering community due to economical and safety issues. Corrosion of concrete reinforcement causes changing of nonlinear behaviour of reinforced concrete structures and ignoring these changes may lead to structural damage during the design life time of RC structures. Investigation of reinforcement corrosion effects in concrete structures on nonlinear behaviour of reinforced concrete members is the main subject of this research. In this study, the structural behaviour of the moment-curvature curve was investigated under these corrosion effects. After occurring the corrosion, cross section of the reinforcement is gradually reduced and consequently load bearing capacity of the reinforced concrete members will be reduced significantly. Accordingly, the relationship between corrosion and moment-curvature curve of structural members will be discussed. A two-dimensional frame is considered to investigate the seismic behaviour of structural frame and members, under different scenarios of corrosion in comparison with the approach proposed by Instruction for Seismic Rehabilitation of Existing Buildings (No. 360). Based on these results, to take the corrosion effects into consideration, it is recommended to use a k factor associated to ultimate sectional capacity instead of ductility limit.

Recently, decisions and debates related to it, such as the allocation of credits for planes and projects at the country level and at managerial levels, are a major issue in organizations, ministries and official institutions of the country. The proposed model for budget allocation is a tool for accelerating decision making by managers. In this research, which was conducted to prioritize development projects at Science Research and Technology ministry , in addition to the management decision making quicknessusing, it has been tried to answer the question ,which is the most appropriate choice among options available (projects) using multi-index models? This method is based on decision-making and decision-making matrix basis. To this end, in this research, a multi-index model is used to answer what factors are to be allocated This research studies how to design aeffective model for allocating credit to development of the construction projects in the Ministry of Science, Research and Technology using multi-criteria techniques. The purpose of this research is to identify and rank effective indicators on credit allocation and Their grading (importance coefficient) and choosing the optimal option and preparing a credit allocation model. After initial refinement among the indicators and criteria, using the fuzzy hierarchical process method and the fuzzy topisation method, which are the multi-Criteria decision-making methods and with the help of MATLAB software and other related software which is one of the most important tools for accelerating multi-criteria decision-making techniques, criteria and indicators are ranked and weighted.

The steel plate shear wall (SPSW) system has emerged as a promising lateral load resisting system in recent years. However, seismic code provisions for these systems are still based on elastic force- based design methodologies. Considering the ever increasing demands of efficient and reliable design procedures, a shift towards performance based plastic design (PBPD) procedure is proposed in this work. The proposed PBPD procedure for SPSW systems is based on a target inelastic drift and pre-selected yield mechanism. The proposed procedure is tested on a four-story building with rigid connections. Three different designs are considered: (1) the code design (2) the DBE design and (3) the MCE design. In addition, the displacement profiles and the selected yield mechanism are also compared at target drift.

Reinforcement inside the concrete is protected from corrosion and its damages until several years after the construction. After corrosion initiation, the Cross Section of Reinforcement begins to reduce and often load bearing of the reinforced concrete structure will be reduced significantly. Corrosion of reinforcements in concrete in polluted and contaminated areas can be occurred in two ways: Chloride and Carbonation. Chloride ion ingress is one of the major problems that affect the durability of reinforced concrete structures such as bridge decks, concrete pavements, and other structures exposed to harsh saline environments. Corrosion occurrence and development in reinforced concrete structures increase the steel volume and produce products with volume of about 2-7 times the steel initial volume. This volume increase, which is due to cracks, reduces the compressive and tensile strengths in reinforced concrete structures. Therefore, durability based design of concrete structures in marine areas has gained great significance in recent decades and various mathematical models for estimating the service life of reinforced concrete have been proposed. In spite of comprehensive researches on the corrosion of reinforced concrete, there are still various controversial concepts. Effect of environmental conditions on durability of concrete structures is one of the most important issues. Hence, regional investigations are necessary for durability-based design and evaluation of the models proposed for service-life prediction. The Persian Gulf is one of themost aggressive regions of the world because of elevated temperature and humidity as well as high content of chloride ions in seawater. Corrosion of reinforcement due to chloride ions attack causes enormous damages to structures in severe condition of marine environments. Normally, high alkaline property of concrete (PH≈13) forms a protective oxide layer on the steel surface. This is called a passive protection. The dioxide existing in the atmosphere or the chloride in the concrete environment along with the moisture and the oxygen can penetrate via the concrete pores and cracks and can reach the armature surface; then, by reducing concrete alkalinity, they cause armature corrosion inside the concrete by destroying the protective oxide layer on the steel. Chloride ions reach the passive layer according to the explained pattern and they begin to react in the passive layer when the amount of chloride ions go beyond the critical value and cause perforation corrosion. Since each influencing factor in the life time of the structure is subject to random variability and inherent uncertainties, a stochastic approach is utilized to predict the time for initiation of the corrosion. Based on Fick’s law, time for corrosion is a function of surface chloride, critical chloride, concrete cover thickness, and diffusion coefficient. The most common models service-life prediction of reinforced concrete structures under load chloride, only produce a limited definite time for the start of corrosion. In this paper monte carlo simulation use for service-life prediction of reinforced concrete structures of predict the time of corrosion initiation, and shown the influence of mean and standard deviation variations for each of the parameters that affect the occurrence of corrosion, on the time of initiation corrosion and impact of these factors on the probability initiation corrosion.

Aggressive marine environments and tidal conditions due to chloride ions attack and subsequent wetting and drying concrete, lead to excessive corrosion of reinforcing steel that creates destruction. Simulating behavior of corrosion can be effective in reducing the damage, regional investigations are necessary for durability-based design and evaluation of the models proposed for service-life prediction. In this paper Monte Carlo simulation use for service-life prediction of reinforced concrete structures in tidal zone. This study evaluates the influence of mean and standard deviation variations for each of the parameters that affect on the time of corrosion initiation. In tidal condition that studied in this paper, in the case of 10 mm convection depth with respect to non tidal zone, the service life of the structures decrease about 15 years. So it is found the effect of corrosion occurrence to standard deviation of concrete cover that must be noticed in constructions of marine structures.

Experimental and numerical study have carried out on behavior of Steel Plate Shear Wall (SPSW) and also, its good performance during past earthquakes have been testified a capable system against lateral load. The system have high ductility, stiffness and strength under seismic loading during a sever earthquake. Although, enormous studies have been performed till now, there are several unkhown problems about this system. Effect of crack on SPSW behavior is obviously one of the important between the unkhowns that have considerable effect on the behavior of SPSW. Therefore, in this study the effect of crack on SPSW is investigated. Results indicated that central crack is more critical than edge cracks. The results show that long central cracks cause the system fails in a brittle manner. In addition, a model have been proposed to obtain load-displacement curve without finite element modeling. On the proposed model the crack and its propagation is consider.

Direct analysis method is a new approach on stability design of steel structures. This method consider second order effects by applying lateral force and reducing stiffnesses, however the effective length method consider these effects by increasing column length. The direct analysis method takes the effective length factor unity for all members. Joints displacement, out of straightness and out of plumbness as initial imperfections can be modeled directly or alternatively by applying notional loads in design considerations. Inelasticity and geometric nonlinearities calculated by reducing member stiffness in design considerations. In heavy oil structures, significant gravity loads and column length lead to more second order effects in compare to typical structures. This study evaluates and compares nonlinear dynamic analysis responses of designed heavy oil structures in both direct analysis method and effective length method based on ANSI/AISC 360-10 provisions.

Having very simplicity, nonlinear static procedures (NSPs) are the most popular tools for estimation of structural capacity. These approaches construct a graphic display of the overall structural response via a pushover curve. The overall response of the system provides a direct simulation of the building as single degree of freedom (SDOF) system that simplifies the design and evaluation of the structure. In this research, the first step in any nonlinear static analysis or in other words perform a pushover analysis has been studied. Applied lateral load to the structural model not only affects the overall responses of the structure through structural capacity curve, but also directly affects the local responses of the structure. In order to evaluate these lateral loads, steel buckling restrained braced frame structures are examined by advanced modal pushovers. Next, the results of these pushover analyses will be compared with nonlinear time history analysis as the most accurate method. Finally, the most efficient method in this particular structure is introduced. The analysis conducted in these structures shows that the lateral load pattern based on story shears offers a good prediction of the maximum response of the concentrically buckling restrained braced frame buildings.

T h e p i e r s o f m a n y b r i d g e s i n o u r c o u n t r y, w h i c h w e r e c o n s t r u c t e d l o n g a g o, h a v e b e e n e x p o s e d t o c o r r o s i v e f a c t o r s t h r o u g h o u t t h e y e a r s a n d, i n m a n y c a s e s, t h e s e f a c t o r s h a v e c a u s e d d e s t r u c t i v e e f f e c t s. C r e a t i n g a n e w 3D a n a l y t i c a l m o d e l t h a t c a n c o n s i d e r t h e e f f e c t s o f t h e c o r r o s i o n o f r e i n f o r c e m e n t o n c o n c r e t e c o l u m n s a n d u s i n g t h e p r o p e r m o d e l f o r n o n l i n e a r f i n i t e e l e m e n t a n a l y s i s i s t h e m a i n o b j e c t i v e o f t h i s r e s e a r c h. A s c o r r o s i o n b a s i c a l l y c a u s e s a r e d u c t i o n i n t h e s t r e n g t h o f m a t e r i a l s a n d c o n s e q u e n t l y d e c r e a s e s t h e c a p a c i t y o f t h e b r i d g e p i e r s, c o n s i d e r a t i o n o f t h e i r r e a l b e h a v i o r i s o f g r e a t i m p o r t a n c e. T h e r e a r e a l s o s o m e o t h e r f a c t o r s w h i c h a f f e c t t h e n o n l i n e a r b e h a v i o r o f r e i n f o r c e d c o n c r e t e s t r u c t u r e s, s u c h a s t h e s t r e s s-s t r a i n r e l a t i o n o f c o n c r e t e i n c o m p r e s s i o n, c r a c k s i n c o n c r e t e, t h e c r u s h i n g o f c o n c r e t e, a g g r e g a t e i n t e r l o c k a n d d o w e l a c t i o n. I n a d d i t i o n, t h e c o r r o s i o n o f r e i n f o r c e m e n t s i s o n e o f t h e c r u c i a l c a u s e s i n a f f e c t i n g t h e n o n l i n e a r b e h a v i o r o f c o n c r e t e s t r u c t u r e s, b y w h i c h t h e l o a d i n g c a p a c i t y a n d d u c t i l i t y o f c o n c r e t e s t r u c t u r e s a r e r e d u c e d. T h e r e f o r e, t h i s f a c t o r i s a l s o c o n s i d e r e d u s i n g t w o m a i n a p p r o a c h e s, w h i c h a r e: r e d u c t i o n i n t h e a r e a o f r e i n f o r c e m e n t s a n d t h e b o n d i n g o f c o n c r e t e t o t h e r e i n f o r c e m e n t s, w h i c h a r e u t i l i z e d i n t h e t e n s i o n s t i f f e n i n g m o d e l a n d i n t h e v a r i a t i o n o f s t e e l p r o p e r t i e s. I n t h i s s t u d y, t h e a f o r e m e n t i o n e d c a u s e s a r e i n t r o d u c e d w i t h c r e d i t e d w e l l-k n o w n r e l a t i o n s a n d t h e y a r e u s e d i n t h e p r e s e n t e d m o d e l. I t i s a l s o w o r t h y t o n o t e t h a t i n t h i s s t u d y, t h r e e r e c t a n g u l a r c o l u m n s a r e m o d e l e d i n a n e w f i n i t e e l e m e n t p r o g r a m, u s i n g a n a d v a n c e d c o m p o s i t e e l e m e n t, n a m e d; t h e S o l i d S h e l l E l e m e n t, i n t w o d i f f e r e n t c a s e s. I n o n e c a s e, t h e c o r r o s i o n e f f e c t s o f r e i n f o r c e m e n t s a r e c o n s i d e r e d, w h i l e, i n t h e o t h e r c a s e, t h e c o r r o s i o n e f f e c t s a r e i g n o r e d a n d t h e a n a l y s i s r e s u l t s o f t h e t w o m o d e l s a r e c o m p a r e d t o t h o s e o f l a b o r a t o r y e x p e r i m e n t s.

Many countries have their own specific code for seismic resistant design of structures. In all these codes, it is important to know site characteristics, site seismicity, building importance, type of structural resistant system and situation of building. corresponding, coefficients in different codes are varied. Defining the base shear and its distribution at floor levels are based on elastic analysis, which cannot simulate the actual behavior of structure under severe ground motions. This is mostly contributed to the formation of plastic hinges along the height of the structure which are not accounted for in elastic analyses. Therefore, new method referred to as "performance based plastic design" (PBPD) has been used to simulate the actual behavior of structures under severe ground motions. In this paper, the seismic performance of eccentrically braced steel frames with symmetric horizontal links (H-EBF) that are designed based on Iranian 2800 standard code (3rd edition), IBC 2009 and PBPD are compared. In PPBD method, the plastic hinge, story displacement and plastic rotation of links are uniformly distributed along the height and nonlinear behavior of the structure is accounted for.