Nowadays nonlinear analysis methods are employed for the seismic evaluation and strengthening of various structural systems. Detailed investigation of the actual performance of buildings during earthquakes and the development of economically optimized designs clearly demonstrate the necessity of performing nonlinear analyses. In performance-based seismic design, structures are designed to achieve different expected performance levels corresponding to different seismic hazard levels. One of the most important steps in performance-based seismic design is the determination and calculation of the performance point. To evaluate the structural performance, nonlinear analyses can be utilized, which are generally >Accordingly, various approximate methods for determining the structural performance have been proposed in seismic codes and guidelines. Among these methods are the Displacement Coefficient Method, the Capacity Spectrum Method, and the Improved Capacity Spectrum Method (N2 method). The objective of this study is to evaluate the accuracy of these methods in estimating the performance point. For this purpose, several reinforced concrete building frames are modeled, and their performance points are calculated using the aforementioned methods. To assess the accuracy of the results obtained from these methods, nonlinear time history analyses are performed on the same frames. The results of the nonlinear time history analyses are considered as reference (exact) results and are used as a basis for evaluating the level of approximation and accuracy of the Displacement Coefficient Method, the Capacity Spectrum Method, and the Improved Capacity Spectrum (N2) Method.          Keywords: Performance Point, Nonlinear Static Analysis, Capacity Spectrum, N2 Method

     ميراگرهاي تسليمي U-شكل   به دليل قابليت بالاي اتلاف انرژي، نقش كليدي در بهبود عملكرد لرزه‌اي سازه‌ها ايفا مي‌كنند. در اين پژوهش، رفتار چرخه‌اي اين ميراگرها با استفاده از روش اجزاي محدود در نرم‌افزار آباكوس مورد مطالعه قرار گرفت. در گام نخست، مدل عددي با استفاده از المان‌هاي حجمي هشت‌گرهي   و با در نظر گرفتن پيش‌تنيدگي پيچ‌ها ، بر اساس نتايج آزمايشگاهي معتبر صحت‌سنجي شد. براي كاهش تمركز تنش، يك هندسه پخ‌دار   پيشنهاد گرديد و سپس ?? مدل پارامتريك با متغيرهاي ضخامت، عرض، ارتفاع ، شعاع انحنا و زاويه بارگذاري تحت تحليل‌هاي استاتيكي غيرخطي قرار گرفتند. نتايج نشان داد كه افزايش ضخامت و عرض و همچنين كاهش شعاع انحنا، منجر به بهبود چشمگير سختي الاستيك، مقاومت نهايي و ظرفيت جذب انرژي مي‌گردد. در نهايت، يك رابطه تحليلي جديد براي پيش‌بيني سختي الاستيك ارائه شد كه نتايج آن با داده‌هاي عددي مطابقت مناسبي دارد. كلمات كليدي : ميراگر تسليمي U-شكل، روش اجزاي محدود، جذب انرژي، تحليل پارامتريك، سختي الاستيك

   This research is conducted in two main stages. First, the behavior of a prismatic fuse-type damper is investigated and analyzed, and then its effect on the seismic performance of reinforced concrete structural frames under cyclic loading is evaluated. In many structures, especially in regions with high seismic hazard, controlling seismic response through energy dissipation systems such as dampers plays a crucial role. Prismatic fuse-type dampers, due to their high energy dissipation capacity and adequate deformability, are considered an effective solution for reducing the seismic vulnerability of structures. In this study, which is based on the use of two numerical analysis software packages, the damper is first modeled independently in Abaqus, and its load–displacement relationship is obtained. Subsequently, structural frames are modeled in SAP2000, and the damper behavior is introduced into the frame models in the form of a link element. The research methodology includes nonlinear numerical analysis of both the damper and the structural frames, which are performed separately using the aforementioned software. Finally, the performance of the frames equipped with dampers is investigated under cyclic loading to evaluate the effect of the damper on structural displacements and stiffness. The results of this study are expected to contribute to the improvement of design approaches for structures equipped with fuse-type dampers and to assist in selecting optimal materials for structural frames.

   Beams made of steel and concrete are called composite beams. steel beams have advantages and limitations. Some limitations of iron can be overcome with concrete, And such a thing has been done in the composite beam. The composite beam uses concrete to provide strength, proper mass, corrosion, and fire resistance and uses steel to provide ductility and tensile strength. Therefore, the importance of this research is to know more about the effective parameters in the bending behavior of prefabricated composite beams. On the other hand, considering that, for economic and technical reasons, the use of composite elements such as composite beams in prefabricated structures is expanding day by day, the need to know the bending behavior of prefabricated concrete-steel composite beams is felt more and more. Therefore, the main goal of this research is to numerically investigate the bending behavior of prefabricated concrete-steel composite beams. For this purpose, after validating the numerical modeling, the effect of various parameters on the bending behavior of prefabricated concrete-steel composite beams has been investigated.

  Humans use lateral bracing systems in structures to deal with the lateral force that is applied to structures through earthquakes. In metal structures, braces are used to deal with this force, which behave in tension and compression. Brace systems are classified into different types, such as divergent and convergent brace frames and knee element braces. Convergent brace systems are more rigid than reduced section frames and bending frames, but less ductile. In order to increase the ductility of frames, the divergent brace system was invented by Mr. Popov in 1987. In this system, a member that was located as a connecting beam along the main beam element of the frame was responsible for energy dissipation. After the earthquake, if the beam element was continuous, the entire element would have to be replaced. However, if the connecting beam was guided and flanged to the main beam, it would be repairable and replaceable. In this case, the roof of the floor would have to be destroyed. After this, researchers searched for a system through research and laboratory studies. In 1986, a system called the Knee Brace Frame (KBF) was developed by Mr. Ochoa, which eliminated the shortcomings of previous systems. This system has reduced the cross-section and the bending frame has more stiffness and energy dissipation compared to divergent systems. In this study, the hysteresis curve of the knee brace frame (KBF) was first extracted through finite element software (ABACUS) and compared with the experimental model for verification. Then, by doubling the column length and considering it for the beam length, this rectangular sample was examined and analyzed in three models in ABACUS. In the KBF1 model, the beam length is 5.6 meters and the column height is 2.8 meters. The knee brace length is 0.55 meters. The diagonal brace X is passed through the beam and column X at the connection node, and the diagonal brace is perpendicular to the knee brace, but the knee brace length is not divided into two equal parts. In the KBF model, the beam length 5.6 meters and the column height is 2.85 meters, the length of the knee brace is 0.55 meters. And the diagonal brace is again perpendicular to the knee brace, but the X of the brace does not pass through the X of the beam and column at the connection node and divides the knee brace into two equal parts. Continuing in the KBF3 model, where the beam length is 5.6 meters and the column height is 2.85 meters, the length of the knee brace is 0.55 meters, the X of the diagonal brace passes through the X of the beam and column at the connection node and the diagonal brace is not perpendicular to the knee element, but the length of the knee brace is divided into two equal parts. Continuing in the form of a square model, which considers the height of the beam and column as 2.8 meters and the length of the knee brace as 0.22 meters, and the X of the diagonal brace passes through the X of the beam and column connection node and the diagonal brace is perpendicular to the knee element and divides the length of the knee element into two equal parts, but makes the length of the knee element much shorter, as much as twice the length. The knee element length in KBF1 mode is considered to be 22 cm, which means that the square model shows better stiffness, energy dissipation, and lateral load-bearing capacity than the other models. In this study, the behavior of steel materials and welds is controlled by failure criteria in different parts of the connection and the failure mechanism.

In the seismic design of steel structures, the use of efficient lateral load-bearing systems capable of dissipating energy and controlling displacements is of great importance. Steel shear walls are widely used, but the main challenge with thin plates is the phenomenon of out-of-plane buckling, which can occur before full yielding and reduce the system's load-bearing capacity. This research aims to evaluate the potential of using aluminum shear walls as a ductile alternative by numerically and parametrically investigating the seismic performance of steel frames strengthened with this system. The present study was conducted using the Finite Element Method in ABAQUS software. To ensure the accuracy of the modeling, a numerical model was first developed and validated against the results of a reputable experimental study on a steel shear wall, achieving a suitable agreement between the force-displacement curves. In the main phase of the research, a comprehensive parametric study was performed on a single-story, single-bay steel frame strengthened with an aluminum shear wall. The primary variables included the aluminum panel thickness (at three levels: 1, 2, and 3 mm) and the ratio of the wall width to the bay span (at ten levels from 0.1 to 1.0), forming a total of 30 models. All models were analyzed under quasi-static cyclic loading, and indicators such as strength, stiffness, and energy absorption were extracted. Finally, the effect of adding a cross-shaped stiffener to one of the models was also evaluated. The results showed that adding an aluminum shear wall significantly improves the seismic performance of the frame. In the optimal case (F-1-3), the ultimate strength increased by 2.41 times, the initial stiffness by 12.42 times, and the energy absorption capacity by 5.81 times compared to the bare frame. It was found that increasing both the thickness and width of the wall directly leads to the enhancement of all performance indicators and, by controlling buckling, shifts the structural behavior towards the formation of a uniform and stable diagonal tension field. Furthermore, the addition of a stiffener, with a 42% increase in ultimate strength, proved its effectiveness as a viable strategy for optimization and further increasing the system's load-bearing capacity.   

Seismic isolation is one of the most effective technologies available in reducing the seismic response of many structures. Elastomeric isolators reinforced with steel plates are considered one of the conventional types of seismic isolators that have good isolation performance in large and heavy structures. The use of these isolators in lightweight structures lacks technical justification due to the inability to achieve appropriate isolation periods. The aim of the present study is to investigate the behavior of a new type of elastomeric isolators with effective application in lightweight structures. The isolators under study are fiber-reinforced elastomeric isolators with a circular cross-section with holes that are used as supports. Due to the elimination of the end steel plates and the smaller volume of materials used in the construction of the isolator, the total cost is reduced. The presence of a central hole in the isolator leads to a decrease in the effective horizontal stiffness of the isolator and, as a result, an increase in its seismic isolation efficiency. So that these isolators, which have both high technical potential and low economic cost, can be used to isolate light structures and heavy industrial equipment. In this study, using the finite element software Abaqus, these types of isolators have been designed and analyzed with the aim of isolating light structures for effective vertical forces of 150, 250 and 350 kN. Under each of the mentioned vertical loads, three different types of isolators with the same external diameters and different internal diameters have been designed. The internal diameter (hollow diameter) is considered as a variable and the force-displacement curves of the isolators in the vertical and lateral directions have been determined by finite element analysis and the reduction in their vertical and horizontal stiffnesses compared to the corresponding solid circular isolator has been obtained. In the following, two analytical equations for calculating the vertical and horizontal stiffnesses of circular isolators with holes, considering their supporting boundary conditions, have been obtained through regression with an error of less than 10%. These relationships can be used for the initial design of supported circular hollow fiber reinforced elastomeric isolators.   

   Abstract The use of supplemental dampers is considered one of the innovative methods for seismic retrofitting of structures. Among the various types of dampers, buckling-restrained braces (BRBs) are more commonly utilized across the country. This study investigates the impact of BRBs installed on scissor-like bases on the structural performance of a three-story frame. The primary objective is to evaluate the influence of design parameters such as the length and installation angle of the BRBs on controlling structural vibrations. The studied frame, used in the SAC project and well-documented in the literature, serves as the basis for this research. Nonlinear time history analyses are employed to assess the seismic behavior of the structure, including base shear, column moments, maximum roof displacements, and energy curves, both with and without BRBs. The study aims to evaluate the effectiveness of different BRB configurations in reducing seismic responses. The structural modeling and BRB integration were conducted using the SAP2000 software. Force-displacement hysteresis curves of the BRBs were also extracted and analyzed to identify the optimal length and installation angle. The BRBs used in this research, referred to as Chevron Base BRB 3, feature two dampers installed on scissor-like bases resembling a figure-eight configuration. The optimal installation angle for Chevron-based BRBs was found to be 45 degrees, while the ideal BRB length was determined to be 2.5 meters. The findings of this study are specific to the analyzed frame and may not necessarily be generalized to other frames or structural systems. Keywords:

Earthquakes are one of the damaging factors that threaten the stability of technical buildings and vital arteries in many parts of the country. Therefore, seismic improvement of structures and technical equipment in vital arteries is necessary for the sustainable development of the country. Ground-mounted power transformers located in power distribution substations in urban areas are an example of technical equipment vulnerable to earthquakes. Due to the significant mass of these equipment, a significant inertial force is exerted on them during an earthquake, which can cause the equipment to slip or overturn and disrupt its performance by causing damage. One of these effective methods of seismic improvement of the described equipment is to reduce the accelerations affecting them during an earthquake using seismic isolation technology. The purpose of the present study is to study the feasibility of isolating heavy technical equipment with limited dimensions using only one elastomeric isolator reinforced with supporting ring fibers. To achieve the research objectives, ring isolators with different dimensions were designed for a selected transformer weighing 5000kg using the finite element software Abaqus. The outer and inner diameters of the isolator were changed as design variable parameters to study their effect on the lateral behavior of the isolators. In the present study, the range of changes in the outer diameter was from 1000mm to 2000mm and the range of the ratio of the inner diameter to the outer diameter in the studied isolators was 0.7 and 0.9. The results of numerical analyses show that with increasing the inner diameter of the isolator, the effective lateral stiffness and its lateral displacement capacity decrease. The achievable separation period in the isolated transformer can be increased by 1.5s and the maximum ground acceleration effective on the equipment can be reduced by 45%. Another part of this research is to develop analytical relations to estimate the vertical and lateral stiffnesses of ring isolators. The analytical relations presented in this study can be used in the initial design of the isolators. The results of this feasibility study show that fiber-reinforced elastomeric ring isolators have good potential for application in seismic isolation of technical equipment. However, for the practical application of these isolators in technical equipment, it is necessary to conduct laboratory studies and investigate the effect of various parameters on their behavior.   

  Humans use lateral restraint systems in structures to deal with the lateral force that enters the structures through earthquakes, and braces are used in metal structures to deal with this force, which behave in a tensile and compressive manner. Braces are classified in different types, such as divergent and convergent bracing frames and knee element bracing systems. Convergent bracing systems have a reduced cross-section compared to frames and the bending frame is more rigid but less malleable, in order to increase malleability. Frames In 1987, the diverging brace system was invented by Mr. Popov. In this system, the member that was located as a connecting beam along the length of the main beam element of the frame was responsible for energy consumption. After the earthquake, if the beam element was continuous, the entire element should be replaced and replaced. If the connecting beam was guided and installed in the main beam with a flange connection, it could be repaired and replaced, otherwise the roof of the floor would have to be destroyed. In 1986, a system by Mr. Ochoa called the knee brace frame(KBF)which fixed the shortcomings of the previous systems. Compared to the divergent and segmental systems, this system has reduced stiffness and more energy consumption of the bending frame. In this study, first, through the finite element software (Abaqus), the hysteresis curve of the bending frame was calculated. With the knee brace, we extracted and compared it with a laboratory model for validation. In the following, we checked the same bending frame by removing the knee element, and then by increasing the length of the knee element and changing the knee connection from bending to joint, which in the first case, considering The bending frame means the connection of the beam to the welded support column and the support bracket (welded) and the increase in the length of the knee element, the stiffness and the energy consumption and the lateral load are increased. In the following, all these models are changed from the connection of the beam to the support column in the previous state to a joint (welded joint). We have changed and considered the bracing to be of the welded type, which reduces the hardness, energy consumption, and side load a little, which in the following is in a similar model, such as the verification sample of the connection of the beam to the hinged column (welded) and considering the brace to be of the hinged type (pin) Considering that the hardness and energy consumption have decreased, but the resistance limit has slightly decreased with s Shear and bending mode in the link beam is dealt with in EBF frames, and if there is an architectural need and creating an opening in the frames, KBMF frame can be used with the failure of the link beam shear mode because it has Translated from Persian to English - www.onlinedoctranslator.com better stiffness and energy consumption. In this study, the behavior of steel and welding materials has been controlled by failure criteria in different parts of the connection and rupture mechanism

  يكي از سيستم هاي

  سيستم مهاربندي كمانش تاب با استفاده قابليت استهلاك

connections experienced brittle failure. Therefore, in order to prevent the brittlefailure of connections and to protect the main structural members from damagedue to seismic forces, slotted steel dampers were used at the beam-to-columnjunction. The analyzes carried out in the finite element software showed that in thecase of using slotted dampers with a conventional slot shape, the stressconcentration is only created at the end points of the strips and the middle parts donot play a role in energy consumption. In order to solve this problem, in this study,semi-elliptical gaps were used in the slotted damper. Then, the influence of thewidth of the damper strips on the seismic performance of beam-to-columnconnections was investigated. The results of the analysis showed that the use ofthe proposed slotted damper improves the seismic performance of the connection.Also, by reducing the distance between the slits, the participation rate of the middleparts of the slitted damper strips in energy absorption increases. In the next step,the effect of the distribution of the height of the slits on the behavior of the slotteddamper in beam-to-column connections was investigated. The results ofexamination of the samples in the finite element software showed that thedistribution of the height of the slits in the slotted damper with the shape of a halfelliptical slit with a slope of 2 degrees in such a way that the lowest slit height isin the corner and the highest slit height is in the middle, has the highest energyabsorption and ultimate resistance.Key words: earthquake, slit damper, semi-elliptical slot, strip width, slit heightdistribution   

The bending frame is one of the favorite lateral load systems of structural designers due to high redundancy. This type of lateral bearing system shows good ductility and energy dissipation. In recent years, progressive damage in various structures has caused irreparable financial and human losses, and the increase in such damage in the structure has led structural engineers to know and deal with such damage. after the 1994 Northridge and 1995 Kobe earthquakes, several studies were conducted on the seismic performance of beam-to-column connections and two general approaches to improve the seismic performance of connections emerged. Strengthening the connection of the beam to the column and weakening the cross section of the beam. By weakening the cross section of the beam, a part of the cross section of the beam near the connection to the column is reduced, and the potential for the formation of a plastic hinge is placed in that place. Weakening the beam cross-section is more economical than strengthening the connection and prevents failures such as weld failure at the beam-to-column connection, which was seen abundantly in the Northridge earthquake. this study ; for improve the performance of steel bending frames with RBS connections after the sudden removal of the column in During progressive failure, A new model has been presented by using a curved steel piece under the title of quarter-circle element. Validation of the laboratory sample has been done in Abaqus 2022 software, and in order to see the effectiveness of the proposed model, we will do parametric studies on the influence of the outer radius, thickness and width of the quarter-circle element. The results of the studies indicate that the proposed model has a positive effect on the strength and ductility of the connection and does not prevent the formation of a plastic hinge in the place of the reduced section of the beam.   

   Investigating the seismic behavior of frames braced with CFT columns

  Abstract:In general, additional dampers or energy absorbers are usedto reduce the dynamic response of the structure against earthquake load andwind load. The structure of these devices is such that by applying special andspecific deformations and special mechanical actions, they first absorb andthen deplete a huge part of the energy input to the structure due to impact anddynamic loading. The functional behavior of these devices is the reason thatthe energy received by other members from structures should be reduced and weshould not witness many changes in their shape after the earthquake. Ingeneral, the mechanism and performance and energy absorption structures ofthese dampers include 3 general methods of friction and visco-elastic behaviorand the use of the flow properties of stable metals.. Amongthe advantages of these devices, we can point out their use in the improvementand retrofitting of existing structures with a new method. The reason for thisissue is the special shape of these devices as well as their location, whichare generally placed in wind braces. These devices can be easily placed in theexisting structures and may even be replaced if necessary after the loadingtime (earthquake event). Due to the large number of non-resistant and safe structuresagainst earthquakes in our country, Iran, and the need to use new methods inthe design of non-resistant and safe structures due to earthquake loads, whichreduce the dynamic response of structures in a suitable way. Inthis upcoming research, we are looking to find the numerical placement ofrotational friction damper in reinforced concrete frame. For this purpose, twofinal strength parameters and the hysteresis diagram of concrete frame withrotational friction damper were checked after verification under barcyclic ineleven proposed models. and found the optimal numerical model frame accordingto these two parameters, and for this purpose, the dimensions of the frame of aone-storied opening with a length of 5.0 meters and a height of 3.2 meters fromthe middle opening of the seven-story concrete frame and the first floor andthe lowest floor with a dead load of 500 kg/m and live load of 250 kg/m wasselected. After calculating the sliding load of 80,000 kilonewtons forthe frame with a diagonal brace, eleven proposed models were made using theFiliatrat and Cheri method, and at the beginning of the validation work, theframe and damper were each done individually. The support was the onlyrotational friction damper on the column along with the Chevron brace modelwhich had two dampers, the support of the dampers was on the beam, as well asthe single damper cubic panel model, which was supported on the beam, with95,000 Nm of energy, they had the highest energy consumption of the frame. Theultimate strength of the diagonal brace frame has the highest ultimate strengthwith 600,000 newtons of resistance.

  The use ofdampers in the connection of steel beams to precast concrete columns has provento be effective in improving the performance of various types of connections.Dampers increase energy dissipation capacity and limit structural damage undersevere seismic loads. The main objective of this research is to employscientific and professional methods based on documented and useful data toaccurately analyze the performance of various dampers in the connection ofsteel beams to precast concrete columns. Comparative analysis of thisconnection with changes in damper parameters and components will be carried outusing numerical methods in finite element software such as Abaqus and itscounterparts. According to the research findings, the ratio of the total energyof the friction damper to the reference model is equal to 1473, for the metaldamper it is equal to 52 and for the combined damper it is equal to 10.Therefore, it is logical to use friction damper in areas with high earthquakeintensity. The final resistance ratio of the friction damper model to thereference model is equal to 7.5, for the model equipped with a metal damper itis equal to 26 and for the combined model it is equal to 60. This means thatcompared to the rest of the models, the hybrid damper will yield later andrequires more force to yield, and it will perform well in areas with strongwinds and to face moderate earthquakes. It will work well.

   استفاده از مقاطع توخالي در اعضاي باربر سازه، مزيت كاهش وزن مخصوص را دارند؛ كه به سبب وزن كمتر، عملكرد بهتري را در مقابله با زلزله از خود نشان مي­دهند. الياف موادي ايده­آل براي استفاده در بتن و ملات­ها مي­باشند و استفاده از الياف در بتن سبب افزايش مقاومت در برابر آتش، سختي، افزايش مقاومت فشاري، خمشي و كششي و دوام مي­شود.پوشش­هاي FRP سبب افزايش ظرفيت باربري ستونها مي­شوند؛ و در سازه­هاي فرسوده واقع در مناطق لرزه­اي، به منظور بهبود شكل­پذيري و به تعويق انداختن شكست ناگهاني، كاربرد دارند. در اين پايان­نامه به بررسي و مقايسه مقاومت شعاعي و مقاومت در برابر حرارت بالا نمونه­هاي استوانه­اي توخالي بتني پرداخته مي­شود؛ بدين صورت كه نمونه هاي بتني، بتن اليافي و بتن با پوشش FRP به صورت استوانه­اي توخالي جدار نازك ساخته خواهد شد و سپس مقاومت شعاعي و مقاومت در برابر حرارت بالا نمونه ها اندازه­گيري و با يكديگر مقايسه مي­شوند.

AbstractSteel shear walls are considered as one of the lateral force-resisting systems in build-ings. Sometimes, openings are created inside these walls due to architectural needs and the passage of facilities, which causes the interruption of the power flow inside these walls, and has a negative effect on the structural behavior of these walls. There-fore, this study was carried out aimed to improve the behavior of these types of walls by using elements that will remain in the elastic range and bring their behavior closer to the behavior of the wall without opening. In this study, a laboratory sample of these walls, which has been done before, is first modeled using Abaqus FEA (formerly ABAQUS), and will be subjected to the same laboratory loading and with an increase in the elastic part. The elastic part of the wall's performance will be checked in differ-ent situations after ensuring the correctness of the modeling according to the corre-spondence between the software answer and the laboratory work by changing the ge-ometrical characteristics, and the best reinforcing technique will be selected from among the reviewed cases.Keywords: Steel wall with opening, Cyclic loading, Reinforcement  

   Owing to the vital role of electrical energy in the daily lives of people, the stability of distribution networks after natural crises such as earthquakes is of particular importance. Aerial substations are among the most important equipment in distribution networks, and their proper seismic performance plays a significant role in the continuity of electricity flow during an earthquake. A review of the damage caused to the distribution networks by past earthquakes shows that the mentioned substations sometimes lack good seismic performance owing to design and construction weaknesses. In this thesis, the performance of distribution network aerial posts in previous earthquakes and existing standards in this field were reviewed and assessed. The objective of this thesis is to evaluate the seismic behavior of one of the aerial substations of the Kermanshah Province Electricity Distribution Company using finite element analysis. For this purpose, a 12 m long reinforced concrete pole with a nominal strength of 400 kgf was modeled using the finite element method in the Abaqus software. In the finite element model, the nonlinear stress–strain behavior of concrete is defined with the possibility of determining its damage index, and the stress-strain behavior of steel is introduced into the software with a bilinear curve. The finite element model was validated using the results of the static loading test of a 12 m long pole (available in the literature). Next, an aerial substation, a 315 kVA transformer (with a total weight of 1210 kgf) that was installed at a level of approximately 5 m from the ground level on a metal platform connected to two 9 m and 12 m long reinforced concrete poles, was introduced and modeled using Abaqus software. The transformer platform was connected to the 12-meter concrete pole of the post through two short C-sections that transferred the weight of the transformer to the pole by relying on the frictional resistance. Therefore, the contact surfaces between the concrete pole and the C-sections (as the support of the platform beam), which are prone to relative slip during earthquakes, were modeled in the finite element analysis. Considering that the studied aerial substation is located at the end of the line, the tensile force of the conductor wires connected to the concrete pole is applied as a static force in the finite element model on the 12 m pole of the substation. Finite element analysis includes a nonlinear time history dynamic analysis under the effect of the scaled accelerometer of the 2017 Sarpol Zahab earthquake, Iran, to document the weak point of the friction support of the transformer platform in transmitting seismic loads to its 12-meter base. The results of the analysis show that as a result of the relative slip at the contact surfaces of the C-sections and the 12 m long concrete pole, the transformer experiences significant rocking motions that could cause the risk of breaking the bushings and power outages during an earthquake. By examining the concrete poles of the post, it was observed that cracks and minor concrete crushing failures occurred at the base of the pole. Despite the damage to the concrete in this area, the pole maintained its stability and did not fail.

  Given the high seismicity of many regions in Iran,

  In the real world, shocksfrom low heights to bridges to heavy shocks on protective structures such astrenches , and even the protective structure of nuclear power plants have beenthe focus of many researchers. The impulse loads discussed in the present studyare an important >One of the basicchallenges for structural engineers is the effect of impact load on structuralelements. For this purpose, processing researches were conducted on reinforcedconcrete beams under the effect of impact, but none of them investigated theeffect of various factors such as the type of ECC concrete and the CFRP coatingthat was used for shear strengthening, bending strengthening and shear-bendingstrengthening had not been studied. Therefore, in this research, the main goalof the numerical evaluation of the factors affecting the dynamic performance ofreinforced concrete beams under the effect of impact load has been selected. Toachieve this goal, in the first step, verification has been done, and in thesecond step, the details of the reinforced concrete beam have been determinedbased on valid international regulations. In the third step, 12 numericalmodels are analyzed and then the maximum displacement of the middle of thebeam, permanent deformation, reaction force and their stress distribution arediscussed and investigated.The results of thisresearch show the positive effect of ECC concrete on the behavior of reinforcedconcrete beams. Also, in samples without CFRP coating, comparing the samplewith 100% ECC concrete (Sample E) with the sample with 50% ECC concrete in thetensile part (Sample NE), it can be concluded that the NE sample behavedbetter. Because their maximum displacement was not much different, but sample Eshowed more support reaction force and also permanent shape change and morestress was observed in it.In samples with 50% ECCconcrete, the use of CFRP coating has reduced the permanent displacements ofthe reinforced concrete beam. Also, simultaneous bending and shearstrengthening has had a greater effect in reducing permanent displacements ofnumerical samples.

Connections in precaststructures are of great importance and their design requires great precision totransfer lateral loads such as earthquakes and wind. On the other hand, everyyear, a large number of buildings catch fire and cause a lot of financial andhuman losses. In other words, fire in buildings is one of the serious threatsto the life and financial security of society. Therefore, the necessity ofresearch related to connections in precast structures and the importance ofstudying their behavior after fire is felt more than ever.The resistance ofstructural members against fire is one of the important parameters for having asafe building. Buildings of medium importance and high importance should bestable for at least 90 minutes in fire. Based on this, many researchers havestudied the behavior of beam-to-column connections after fire, but none of themhave investigated the behavior of precast concrete beam-to-column connectionswith metal-yielding dampers under the effect of fire with different diversions.Have not given so, this research is an attempt to fill this scientific gap,that if we have a metal-yielding damper in the connection of the prefabricatedbeam to the column, what is the effect of fire duration on its post-firebehavior?Therefore, in thisresearch, the first goal is to propose a new beam-to-column connection with ametal-yield damper in precast structures, and the second goal is to provide amethod to protect it against fire. The third goal, which is the main goal ofthis research, is to investigate the effect of duration of exposure to fire onits behavior.For this purpose, firstthe new articles were studied and then validation was done in ABAQUS software,and in the next step, several precast beam-to-column connections withmetal-yield dampers were analyzed, and one of them, which had better hysteresisbehavior, was selected to continue this research. In the next step, accordingto past studies, the use of concrete cover was used to protect the connectionin fire conditions. In the next step, after performing the heat transferanalysis, the mechanical analysis was performed. Finally, resistance afterfire, stiffness after fire, heat distribution were discussed in numericalmodels.The results of hysteresisanalysis of beam-to-column connection in pre-fire conditions show that theproposed beam-to-column connection has good seismic behavior. Also, afterthermal analysis and based on TEMP contour, in numerical models with 10 cmthick concrete cover, increasing the duration of the fire from 60 to 120minutes has caused more fire heat to reach the beam-to-column connection, asthe temperature of the coldest connection point of the beam to the column is about237 degrees Celsius in the 60 minute diversion, and in the 120 minutediversion, the temperature of the coldest connection point of the beam to thecolumn is about 394 degrees Celsius.Also, this research showsthat placing the beam-to-column connection exposed to fire with deflection of60, 90, and 120 minutes, on average, reduces the bending moment by 40, 50, and60 percent, respectively, and reduces the bending stiffness, respectively, byThe value is 39, 47 and 65 percent.  

براي بسياري از كارخانه­ هاي بتن آماده، كارخانه­ هاي ساخت قطعات بتني، پيمانكاران بزرگ و يا كلينيك­ هاي فروش روان­ كننده بتن كه روان­ كننده­ هاي بتن را خودشان تأمين مي­ كنند؛ بررسي اين موضوع كه كداميك از روان­ كننده­ هاي موجود در بازار مي ­تواند منجر به توليد بتني با مقاومت بالاتر و كيفيت و دوام بهتري شود حائز اهميت است كه موضوع اصلي پايان­ نامه مي ­باشد. براي اين منظور نمونه­ هاي بتن پرمقاومت با فوق روان ­كننده هاي 5112 IR شركت سيكا پارسيان، VERTEX-F2 شركت دماوند سفيد، SRJ 572 شركت البرز شيمي آسيا، RM شركت آبادگران و RB-ESP 360s شركت رزين بتن برتر ساخته شد و مطالعات آزمايشگاهي براي مقايسه پارامترهاي اسلامپ، چگالي بتن تازه، مقاومت­ فشاري، مقاومت­ كششي، جذب آب (دوام) و SEM انجام گرفت. نتايج حاكي از آن بود كه نمونه­ هاي بتن ساخته شده با فوق روان­ كننده­ هاي RM شركت آبادگران و RB-ESP 360s شركت رزين بتن برتر به ترتيب مقاومت فشاري و كششي بيشتري نسبت به ساير نمونه ­ها كسب كردند و در آناليز SEM نيز ضخامت ناحيه انتقال كمتر و چسبندگي مناسب بين سيمان و سنگدانه در اين دو نمونه مشاهده شد؛ و سپس نمونه هاي بتن ساخته شده با فوق روان ­كننده­ هاي   RJ 572 شركت البرز شيمي آسيا، 5112 IR شركت سيكا پارسيان و VERTEX-F2 شركت دماوند سفيد به ترتيب با اختلاف كمي مقاومت فشاري و كششي بيشتر و ضخامت ناحيه انتقال كمتر را داشتند. همچنين نمونه­ هاي بتن ساخته شده با فوق روان­ كننده­ هاي   RB-ESP 360s شركت رزين بتن برتر و RM شركت آبادگران به ترتيب اسلامپ بيشتر و جذب آب كمتري داشتند كه در نتيجه دوام بهتري نيز خواهند داشت.

Abstract Due to the progress of science and technology in various cultural, social and economic fields, the need to receive data from various databases based on extracting information patterns to achieve life-giving research results is increasing day by day. On the other hand, maintaining the security of private data of individuals and organizations is a key issue in this field, ignoring it will lead to incorrect information and customer dissatisfaction, and will ultimately lead to incorrect research results. One of the most important information data in this regard is medical data, which even according to medical regulations, respecting people's privacy and keeping information confidential is essential. With the world entering the channel of the global epidemic of the corona virus, controlling the epidemic in the first place and finding its cure in the second place has become the challenge of the scientists and doctors of the world. In this regard, the computer science community has offered its role to control the corona virus epidemic to the world. Using deep learning to detect covid-19 from X-ray images becomes a fast method to diagnose patients and manage care services for patients. To achieve better results, we need a lot of data from different information sources, and data privacy as a barrier in this way will prevent engineers from achieving this important goal. Therefore, by introducing federated learning, which is a nascent leap towards creativity and better results, we will introduce its advantages and challenges and simulate it in the diagnosis of Covid-19 and try to take a small step to achieve more accurate results with more data. And of course, more organized to train neural network models, in the meantime, by presenting a strong aggregate approach, we were able to surpass our competitors with an accuracy of 97.04.      Keywords: Federated learning, covid19, x-ray, deep learning

  ABSTRACTOne of the most importantreasons for the destruction of structures under seismic loading is the ruptureof the beam-to-column connection area. Due to the fact that the details ofconnections have a significant effect on the behavior of the connection and theamount of displacements and reactions created in the structure, with thecorrect and optimal design of the connections, a significant change can be madein the behavior of the connection and the performance of moment frames. Beamconnections with a reduced cross-section are widely used in structures due totheir good ductility and strength. This type of connection is a common methodto prevent the formation of plastic hinge in the column. In these connections,by weakening a part of the beam section, the plastic hinge moves away from thecolumn face. In other words, in this type of connections, the reduced part ofthe beam acts like a fuse and is damaged earlier than the rest of the structure.Reducing the cross-section of the beam is done by reducing the flange of thebeam or reducing the web of the beam. Since the flanges are the main beamcomponents that resist the bending moments, some researchers have suggested theweb reduction strategy in lieu of the flanges reduction. The reduction in theweb of the beam increases the damping of the system, and as a result, theenergy consumption capacity of the system also increases, as a result of whichthe drift and acceleration of the floors decrease. Therefore, the aim of thisresearch is to numerically investigate the Reduced Beam Section connectionunder cyclic loading to improve the behavior of the connection using Abaqusfinite element software, during which the samples are reduced by creating holesand slits in the web of the beam and have been studied in terms of dimension andlocation of the reduced area. After the analysis of the samples, things such ashystersis curve, ductility, stiffness, distribution of mises stresses andequivalent plastic strain have been investigated for each sample. The resultsof the analyzes indicate the appropriate behavior of reduced connections whichare reduced by creating slits in the web of the beam in removing the stressesfrom the column face and also improving the ductility of the reducedconnections compared to the non-reduced connection. Also, the mentioned connectionshave been successful in removing the plastic hinge from the beam-to-columnconnection area. It should be noted that with the increase in the area of the reduced sectionin the web of the beam, the ductility increases and the distribution of misesstresses shows a better behavior.Keywords: Reduced web section, Steelmoment frame, Cycling loading, Hystersis curve, Finite element method

  Usually, most of the destructive earthquakes that occurred in Iran and left many casualties and damage were near earthquakes. Earthquakes such as Manjil 1369, Bam 1382 and Sarpol-e Zahab 1396 are examples of these near-field earthquakes that occurred in Iran. Determining the performance and evaluating the structure and its components is important to determine the seismic capacity and requirements. Due to the fact that most instruments enter the nonlinear area during moderate and severe earthquakes, so estimating the exact capacity of the structure requires the use of more efficient methods in the science of structural analysis. In the analysis and design of structures according to the type and manner of application of loads on the structure and the philosophy of seismic design and the occurrence of nonlinear behavior under the forces on the structure due to earthquakes, in order to determine the exact behavior of the structure is necessary. Different nonlinear dynamic analyzes are used. Dampers are considered as the best method to control and improve the behavior of structures as well as to improve the performance of structures. The main purpose of the thesis is to investigate the seismic performance of flexural frames of reinforced concrete equipped with rotary friction dampers. The results showed that the coefficient of increasing resistance for medium flexural frames equipped with dampers was obtained according to the overlay analysis of 2.63 and based on nonlinear dynamic analysis of 2.90. The obtained ductility coefficient for flexural frames with medium ductility equipped with dampers according to the cover analysis is 2.52 and based on nonlinear dynamic analysis is 3.15. The behavior coefficient for medium bending frames equipped with dampers was 6.56 according to the cover analysis and 8.83 according to the nonlinear dynamic analysis. The coefficient of increasing resistance decreases with increasing number of classes, while the coefficient of behavioral ductility has the opposite. The damper improves the three factors of increasing strength, ductility and modifying the response (coefficient of behavior) according to nonlinear dynamic analysis, while the other analysis of the ductility factor for short structures shows the opposite.

  self-healing is related to the repair of cracks due to loading and it can be considered as a reversible fatigue phenomenon. Asphalt mix is ??a self-healing material and has the ability to automatically repair damage when exposed to rest periods. This phenomenon depends on various factors such as temperature, rest time, crack width and bitumen and asphalt properties. The rate of repair at ambient temperature, especially at low temperatures, is slow and the flow of traffic on the road can not be blocked to achieve sufficient repair. On the other hand, self-healing of asphalt concrete is significantly dependent on temperature and when the pavement is exposed to higher temperatures, the amount of repair also increases. Self-healing has been studied in two areas of rejuvenation and rapid heating Is. To investigate the effects of temperature on self-healing, we are looking for the best and most economical means and method for generating heat in the asphalt mixture. Among the heating methods, we can mention heating by electromagnetic waves and microwave. Microwaves raise the internal temperature of the asphalt in a short time, which helps in self-healing. There are several methods for evaluating the quality and quantity of self-healing, such as fatigue-based tests, rupture-based tests, and non-destructive tests. In this study, the behavior of graphite nitride carbon additives and polyaniline nanofibers on nanosilica-modified hot asphalt self-healing was investigated by three-point bending test. First, the flexural strength of the samples was obtained by a three-point bending device, then the samples were repaired by heating by a microwave device for 24 hours, then the degree of improvement was determined. In evaluating the self-healing process in the hot asphalt mixture modified with nanosilica, the analysis of the results showed that by adding nanosilica, the negative effect of zeolite on the self-healing asphalt used to produce hot asphalt is compensated and the self-healing rate of asphalt increases. On the other hand, two additives of graphite nitride carbon and polyanylene nanofibers have a positive effect on self-healing and even improve the self-healing of asphalt mixture up to 80%.

   Abstract Like other steel systems, steel moment frame system is used for various reasons such as high manufacturing speed, high strength, ductility, etc. The significant advantage of this system is the architectural considerations that make it possible to open the openings. This system analysis and design process assumes that the connections have a complete rigid behavior, while this assumption may not be accurate, and the connections’ rigid behavior assumption will cause errors in the analysis and design results.    This paper examines the effect of semi-rigid connections on the behavior of steel moment frames to determine the structure behavior factor. Hence, we analyzed and designed rigid steel moment frames, with different openings and floors, following 2800 regulations and topic 10 of the National Building Regulations. Then, we conducted pushover analysis on the frames and plotted the capacity curve of the frames, once assuming the rigid connection and then considering the nonlinear behavior of the connection. We used two springs with zero length at the end of the beams with the anchor-connection curve to model the connection behavior. The results show that for frames, assuming a rigid connection, the calculated behavior factor is close to 5, which is the recommended value for this structural system in Regulation 2800. In semi-rigid structures, the values ??of the behavior factor are in the range of the behavior factor of the rigid structure.    Keywords: Rigid Connections, Semi-Rigid Connections, Steel Moment Frames, Nonlinear Static Analysis, Extensive and Concentrated plasticity

  Abstract Getting the body by robot fingers despite the constraints of the topics studied by many researchers. In studies conducted so far, investigations of disturbance with the aim of bringing the body to a new stable condition have been considered. In this research, we study the garsping model in three dimensional space, as well as the related topics, first, the kinematic and dynamic modeling of the fingers and the object and the integration of these equations using the adaptive control method. In addition to the usual kinematic and dynamical studies, this paper examines the speed and position of the robot's motion in order to maintain the desired position of the arms and body under its control. The simulation results by MATLAB software have shown that the model reference adaptive control method with disturbance is capable of creating stability for the speed and displacement of the robot arm fingers

  One of the methods for stabilizing earth slopes or excavated ditches is soil nailing, which has been used around the world for about fourteen decades, and many advances have been made in the use of this method. Has been. However, the use of this method in cold regions is more limited than other places with normal temperature conditions due to lack of sufficient studies and lack of necessary information about the response of the nailed earthen wall due to the experience of freezing and thawing cycles. Therefore, in the present study, in order toachieve a comprehensive plan for the proper design of nailed earthen walls in cold regions, using ABAQUS finite element software, numerical modeling of a nailed earthen wall in Brunswick, Maine The United States has made this region one of the coldest regions. The purpose of this study was to numerically investigate the effect of freezing phenomenon on the behavior of nailed earthen wall, to investigate the stresses caused by freezing activity in the nails that strengthen the earthen body, the amount of pressure on the top wall and the amount of body displacement. Soil is the result of experiencing the freezing process. The results obtained in this study are validated based on the results of field operations performed in Brunswick (Duchesne 2003). Finally, in orderto achieve more comprehensive results, the effect of different nailing conditions inside the soil body under the .mentioned conditions has been investigated

در اين پايان نامه به بررسي خواص مكانيكي نانو كامپوزيت تابعي اپوكسي تقويت شده با نانو ذرات سيليس پرداخته شده است. در بسياري از كاربرد هاي مهندسي مواد مركب به دليل مزايايي چون استحكام وسختي به وزن زياد، مقاومت خستگي، مقاومت خوردگي و به ويژه خواص ضربه اي مناسب به طور گسترده مورد استفاده قرار مي گيرند. در سال هاي اخير استفاده از نانو مواد بهمنظور افزايش خواص مكانيكي مورد توجه قرار گرفته است . نانو ذرات سيليس به عنوان پر كننده پوششي براي تهيه تقويت كننده هاي نانو كامپوزيتي پايه اپوكسي استفاده مي شود. جهت بررسي عملكرد تاثير ميزان نانو ذرات سيليس نمونه هايي با درصد هاي وزني مختلف با توزيع يكنواخت و همچنين نمونه با توزيع تابعي ساخته شده است . در ادامه نمونه ها تحت آزمايش تست كشش قرار گرفته و نتايج حاصل از آن جهت بررسي خواص مكانيكي از جمله مدول يانگ ، چقرمگي و... مورد تحليل   قرار گرفته است. همچنين با تهيه عكس هاي SEM كيفت ساخت ونحوه توزيع مناسب نانو ذرات سيليس مورد بررسي قرار گرفته است. با توجه به بررسي عكس ها، آگلومره شدن يا كلوخه شدن ذرات در نمونه هاي با توزيع يكنواخت مشخص شده ودر نمونه تابعي نيز ميزان پيوستگي مرزلايه ها مشخص گرديده است. همچنين در بررسي تحليلي اين تحقيق از نرم افزار آباكوس استفاده شده است . در اين نرم افزار پس ازتعريف خصوصيات نانو كامپوزيت تقويت شده با نانو ذرات سيليس و مش بندي لازم به تجزيه و تحليل نتايج آزمايش تست كشش پرداخته شده است. در پايان، نتايج بدست آمده از مدلسازي با نرم افزار آباكوس با نتايج تجربي مقايسه گرديده و دقت آن مورد بررسي قرار گرفته است. در بررسي نتايج بهبود خواص مكانيكي مشاهده مي شود، با افزايش درصد وزني نانو ذرات سيليس ميزان مدول يانگ افزايش مي يابد.مقدار مدول يانگ نمونه تابعيكه خود تركيبي از نمونه هاي با درصد هاي وزني يكنواخت مي باشد، نسبت به نمونه هاي با توزيع يكنواخت بيشتر است. در بررسي مقدارچقرگي، نمونه تابعي مقداري بيش از هريكاز نمونه هاي با توزيع يكنواخت دارد و نتايج حاصل از چقرمگي در هر دو حالت تجربي ومدلسازي اختلاف جزيي دارند.   

 in,this study, 37 samples were examined, which varies as follows;the amount of rubber pieces as 10 and 20% of the volume of sand, the amount of recycled steel fibers as 0.5% of the total volume of concrete, the amount of microsilica, also, 5% and 10% were substituted for cement, 5 and 10% of methaqualone were substituted for cement and limestone powder was substituted for 10% of cement. compressive strength, tensile strength, flexural strength and water absorption tests were performed.the results show that the addition of steel fibers to the sample with 20% waste rubber and 10% microsilica increases the tensile and flexural strength by 9.9 and 39%, respectively, compared to the reference sample. in addition, adding limestone powder by 10% to the reference sample will reduce the compressive strength by 24%

In today's world, developments are happening very fast and civil engineering plays an important role in providing the basis for the current developments in the world. Concrete and concrete technology have also undergone significant improvements in line with these changes. Reactive Powder Concrete (RPC) is a new type of high-strength concrete (UHPC) and a cement-based material developed through microstructural engineering. This type of concrete was first introduced in France in the 90's by Richard P, Cheyrezy M and has been able to eliminate many of the weaknesses of conventional high strength concretes and much research has been done on this subject in the world of science and and It is also being done. During our research and studies, new angles of this type of concrete attracted our attention and we decided that part of our future research on improving the mechanical properties and improving the quality of reactive powdered concrete and the other part, trying to Addressing weaknesses and shortcomings that have not been addressed to date. We intend to replace the additives with suitable and economical properties and available in the country as an alternative to cement and green reactive powder concrete with a new mechanism and concretes with excellent properties and higher environmental compatibility to produced. In order to increase the final quality of the produced reactive powdered concrete, additional tests were performed to identify the properties of aggregates, modify the granulation of materials and also to perform super-lubricants tests in order to identify materials and materials to control their properties. In this research, two types of heat treatment and standard, as well as in two projects, the effect of internal processing and also the effect of using burnt oil and comparison with standard mold oil with fresh and hardened concrete tests have been done. By using the optimal percentage of microsilica, metakaolin and natural zeolite pozzolans and steel and polypropylene fibers, along with the use of sand and quartz powder as a substitute for part of the sand, we were able to reduce cement consumption by up to 25% and also the percentage of microsilica use. In order to make the design economical, it has been minimized and at the same time produced concrete with very suitable properties and with increasing resistance compared to the control sample, with a compressive strength of up to 173.2 MPa, a tensile strength of 13.1 MPa with a water absorption of 0.9% produced.   

   One of the most important issues in the field of earthquake engineering is finding ways to reduce the seismic force on the members of the building structures. With the advancement of research in this field, control systems were introduced as one of the effective ways to reduce vibrations and protect structural members against earthquakes. Passive control systems do not require an external energy source for their operation and the control force is generated by the movement of the structure. For this reason, they are mostly used. The most important feature in this type of dampers to control the seismic force is the slip load of the damper. Finding an optimal value for this load greatly improves the results of the structural response. Various methods have been proposed by previous researchers to obtain the optimal slip force of friction dampers at the height of the structure. The main purpose of this study is to investigate the methods of sliding load distribution in building floors with friction dampers. For this purpose, 3 reinforced concrete structures with the same specifications and friction dampers are designed and the slip load in their floor dampers is distributed in four common ways and with appropriate accuracy. The studies show that the optimal slip load is achieved when the displacement, acceleration and base shear responses of the structure are in the desired state. It was also found that among the existing methods, nonlinear time history analysis method is the most appropriate method to determine the optimal slip load of dampers in most structures with different heights.

ABSTRACT Today, several factors including increasing bitumen prices, traffic congestion, climate change and premature failure have made asphalt modification inevitable. Weakness in the bitumen structure can cause damage such as rutting in the passage of the wheels, cracking and asphalt bleeding. These failures not only reduce the useful life of the pavement but also the safety of the road users. In cold regions, thermal cracks are common and various reasons have played a role in the formation and growth of these cracks, which bitumen can be considered the most important factor. In this study, in order to improve the properties of bitumen and strengthen it against cracking use GO by 0.05, 0.1, 0.15, 0.2% and LDPE by 1, 3, 5, 7%. The general purpose of this study is to investigation the fracture toughness of HMA modified by GO and LDPE. In order to conduct this research, three-point bending test was performed by SCB sample at two temperatures of 0 and -10 ? with mentioned percentages of additives and control sample. Then marshall test and resilience module were performed for the optimal percentage of additives according to the results of SCB test and control sample. According to the results of Marshall stability test and resilience modulus, the amount of thickness changes of modified mixtures with each additive was calculated and economic analysis was performed by difference between the price of bitumen and additives used. Environmental analysis of pollutants released in asphalt production, damage to crude oil resources and pollutants that endanger human health, was calculated according to the amount of materials saved.   

   One of the most common types of seismic isolators is steel reinforced elastomeric isolators (SREIs) which consist of alternating layers of elastomer and steel reinforcing plates. Unbonded fiber-reinforced elastomeric isolators (UFREI) are a relatively new type of elastomeric isolators. In this type of isolator to control lateral strain and provide vertical stiffness, FRP layers are used instead of steel plates. Additionally, to reduce the cost of isolators, the idea of removing the top and bottom connection plates and the unbonded use of isolators has been considered. In UFREIs, due to the rollover deformation and the reduction of the isolator horizontal stiffness, it is expected that the seismic isolation efficiency is increased as compared to the bonded isolators. In this research, the performance of UFREIs and conventional SREIs in improving the seismic behavior of liquid storage tanks were evaluated and compared. The isolated water tank was modeled using a mass and spring model of three degrees of freedom with convective mass, impulsive mass, and rigid mass. Time history analyses were performed on the fixed-base storage tank, as the benchmark structure, and the two base-isolated tanks with steel-reinforced and unbonded fiber-reinforced isolators. The results show that both types of isolators are effective in significantly decreasing the demand base shear in the tanks. However, seismic isolation increases the displacement demand in the convective mass. Regarding the comparison of the two types of isolators, it was observed that on average, UFREIs in slender and broad tanks are respectively 33.5% and 23.9% more efficient than the SREIs in reducing the maximum base shear forces. Also, there is no significant difference in the maximum displacement of the convective mass in the two isolation systems. The displacement and shear forces developed in the unbonded isolators were found to be less sensitive to the variations of the peak ground acceleration (PGA) as compared with the conventional bonded isolators.

Today, concrete and cement mortars are one of the most widely used building materials. On the other hand, the weaknesses of concrete and failures in projects for various reasons, improving the properties and eliminating the weaknesses of concrete have been considered by researchers. Due to the advancement of technology and materials science, he tried to improve these high-consumption materials by adding new materials and recognizing it. Although adding these materials improves some properties, on the other hand, it weakens others. Civil engineers must use and update their knowledge, according to the place and the need for the best and most optimal form of materials and materials. Polymers and biopolymers are one of the materials used today to improve the properties of concrete. In this study, we investigated the effect of three different types of cellulose and one type of vinyl acetate-ethylene on the properties of concrete. Cellulose Ether is a derivative of cellulose, the most abundant organic molecule on Earth that can be used to improve some properties of concrete and mortar. Cellulose ethers are used in many polymer-modified mortars such as cement coatings, building mortars, tile adhesives, surface coatings and self-compacting concrete. The use of cellulose ethers in cement mortars began in 1960 and to date, several studies have been conducted on the effect of these materials in cement mortars and concrete. Another material used in this study is vinyl acetate, which causes the loss of water in the concrete, which helps the concrete to work. In addition to examining these two substances separately, the combination of these two substances was also examined. According to the performed experiments including slump, air percentage, compressive strength, tensile strength and water absorption, the design of different mixtures of mechanical properties and durability of concrete was investigated. In all samples, for better comparison, the ratio of water to cement is considered constant. The results of increasing energy absorption and decreasing water absorption and decreasing modulus of elasticity were observed in most of the mixing designs. Regarding compressive and tensile strength, materials with different percentages had different effects on these properties of concrete.

  Concrete is one of the most widely used and widely used building materials, which has been especially welcomed in the construction industry due to its easy access and low cost components. One of the most important parts of concrete construction and operation is its processing part, which is necessary to achieve the desired strength, and especially in our country, little attention is paid to it. Lack of proper processing can reduce the mechanical and durability properties of concrete and cause damage to the concrete structure. On the other hand, concrete can be exposed to damage for various reasons, sometimes we need to repair these defects, which can be much more difficult to process the repaired parts, in the presence of materials in Inside the concrete that performs this action, the concrete can achieve the required strength without external processing. Polymeric superabsorbents are a group of materials that can absorb several times their own weight of water and over time this water is removed from their structure, so their type of performance affects the structure of concrete. Concrete samples constitute the statistical population of the research and their construction is in accordance with the standards of Concrete Laboratory (ASTM). In this study, concrete was evaluated by adding two types of polymer superabsorbents in the amounts of 0.6,0.3 and 0.9 and one type of powder polymer in the amounts of 1 and 2 wt% of cement in the ratio of water to fixed cement 0.38. Our evaluation tools in this research are concrete laboratory devices such as concrete compressive strength measuring device, concrete slump cone, etc. We found that the polymer superabsorbents used in this study reduce the flow of concrete. Permeability of concrete is one of the parameters for evaluating its durability, which is reduced by adding polymer superabsorbents, which increases its durability. Polymeric superabsorbents reduce the compressive strength of concrete, which is partially compensated by the addition of ethylene vinyl acetate. At 0.3% by weight of cement, they increase the compressive strength compared to the control sample without processing. They increased the energy absorption compared to the control sample without processing. At 0.6% and 0.9% by weight of cement, the modulus of elasticity decreased. Were observed in concrete, and the addition of ethylene vinyl acetate exacerbates this reduction.

  Concrete is the most widely used material in the world after water. Today, concrete is used much more in structures and construction projects than in the past, so that billions of tons of concrete are used annually in the construction of structures. Due to the rapid advancement of technology in order to save energy, the time and cost of construction projects, new methods and materials have replaced the old methods and materials. One of the newest and most unique concrete products is the concrete canvas, first proposed in 2005 by Berwin and Crawford. Concrete canvas is a composite with cement properties, which can be used in less than 24 hours to achieve a desirable concrete surface with low thickness, waterproof, fire resistant, etc. . In this study, in order to introduce this product, an attempt has been made to investigate the tensile behavior of concrete canvas according to different geometric patterns of 3D fabric, so that to increase the tensile strength in the warp and weft of concrete blanket fabrics. The results obtained were that the larger the number of layers, the smaller the diameter of the hole in the top layer of the fabric and the higher the density of the spacer yarns, the tensile strength of the concrete canvas. It is higher and also the rate of increase of resistance in the direction of weaving is more than the direction of the warp.

  In this paper, the vulnerability of air distribution transformers has been studied qualitatively and quantitatively (analytically). In the qualitative evaluation, according to the trajectories observed in previous earthquakes, the modes of failure of the transformer and their probable cause have been studied according to the evil of their executive environment in the country. Quantitative evaluation with dynamic analysis of a post sample The air has been affected by the acceleration of various earthquakes and the study of internal forces created in critical components. Based on qualitative studies, it was found that the most important weakness in air transformers is the lack of poor resistance of the lille, the lack of lateral restraint at the connection of the platform holding them to the base. These can cause trans (or overturning) of the transformer during an earthquake. The quantitative assessment also shows the vulnerability of the transformer if the retaining platform is not restrained to the base posts. Finally, solutions and suggestions for improving existing posts are provided. Keywords: Transformer bases, interactions of connected bases, seismic improvement, seismic resilience, seismic performance, earthquake damage

  رفتار ديناميكى قابهاى پيش ساخته بتن مسلح همراه با ديوارهاى برشى داراى ميراگرهاى فولادى جذب انرژي

  In the polymer modified concrete, polymer is added to the concrete as the main component to enhance adhesion, ductility and durability. The joint performance of 3D polymer film in conjunction with the materials produced by cement hydration, improves some concrete properties. In this research, experimental studies to investigate the effect of three polymer of methyl methacrylate (MMA), pure acrylic (PA) and styrene butadiene rubber (SBR) with 3, 5, 8 and 10 percent cement replacement on polymer modified concrete containing 5% micro silica was made. The reduction of compressive and tensile strength causes the use of micro silica. To investigate the physical and mechanical properties of concrete, the specimens were tested to slump tests, air ratio of fresh concrete, compressive strength, tensile strength and water absorption.   Also, by drawing stress-strain diagram of all specimens, energy absorption capacity, modulus of elasticity, strain and ductility coefficient were also investigated. The results showed that by adding these three polymer to the concrete, in all specimens, reduced the compressive strength, tensile strength, water absorption, elasticity modulus. The air ratio, the ratio of tensile strength to compressive, energy absorption capacity, strain and ductility coefficient increased. The slump values also increased with the addition of styrene butadiene rubber (SBR) and decreased with the addition of methyl methacrylate (MMA) and pure acrylic (PA).

Performance evaluation of unbounded fiber-reinforced elastomeric isolators against wind

Thermal   vibrations of composite beams reinforced by Boron Nitride nonotubes

دو عامل اصلي در صدمه ديدن سازه ها و محتويات آن ها در حين زلزله، تغييرمكان هاي نسبي و شتاب هاي ايجاد شده در سازه هستند. طرح هاي لرزه اي همواره به دنبال كاهش اين دو عامل و درنتيجه كاستن خسارات وارده مي باشند. جداسازي پايه در سازه ها به طور همزمان موجب كاهش قابل توجهي در مقادير تغييرمكان هاي نسبي و شتاب هاي ايجاد شده در سازه مي شود و لذا با كاربرد سيستم جداسازي لرزه اي علاوه بر امكان طراحي يك سازه مطمئن مي توان به عملكرد اجزاي غيرسازه اي و محتويات سازه نيز در موقع زلزله مطمئن بود. تحقيقات نشان داده اند كه استفاده از ميراگرهاي ويسكوز مي تواند نقش موثري در كنترل پاسخ سازه ها در برابر باد، انفجار و زلزله داشته باشد] 2و1 [. اكثر سازه ها هنگام زلزله هاي شديد با كمك شكل پذيري اعضا با آن مقابله مي نمايند كه سبب آسيب هاي اساسي و بعضا غيرقابل جبراني به اعضاي سازه اي و غيرسازه اي مي گردد. استفاده از ميراگرها مي تواند تغييرمكان ها و شتاب هاي زياد سازه و به تبع آن نياز به شكل پذيري را كاهش دهد. در حال حاضر كشورهاي پيشرفته با مناطق زلزله خيز مانند ايالات متحده، ژاپن و نيوزيلند پيشگامان استفاده از جداسازي لرزه اي در جهان هستند و جداسازي پايه در سازه ها به عنوان رويكرد جديد مقاوم سازي لرزه اي مطرح شده و جنبه عملي به خود گرفته است. در كنار اين رويكرد بسترهاي تحقيقاتي فراواني به وجود آمده است كه تمام مراحل توليد تا اجراي سيستم هاي جداساز را شامل مي شود و تحليل ديناميكي سازه هاي جداسازي شده يكي از مهم ترين اين بسسترها است.مي دانيم كه پيچش اثر معكوس بر پاسخ سازه هاي مرسوم همچنين سازه هاي جداسازي شده مي گذارد. به دليل آنكه 42% تخريب ها در طول زلزله 1985 در شهر مكزيك بخاطر پاسخ پيچشي ساختمان هاي نامتقارن بود، آيين نامه فدرال مكزيك(2و1) اين فلسفه طراحي را   براي سازه هاي مرسوم، از سال 1987 معرفي كرده اند و ديگر آيين نامه هاي مكزيكي مثل منيول سازه هاي مهندسي در اين فلسفه سهيم اند. طبق اين فلسفه اگر خروج ازمركزيت هاي پلان محاسبه شده براي هر طبقه   از 10% بعد پلان در جهت داده شده بيشتر باشد به عنوان سازه هاي نامتقارن طراحي شود و اگر خروج ازمركزيت از 20% بيشتر شود آن ها بايد به عنوان سازه هاي شديدا نامتقارن طراحي شود.هدف اين پايان نامه بررسي اثر جداسازي پايه بر سازه هاي نامتقارن جرمي است. به اين منظور سه مقدار خروج از مركزيت جرمي 10% ، 20% و 30% در سازه با پاي ثابت و سازه جداسازي شده در نظر گرفته شد و پاسخ تغييرمكان هايشان با هم مقايسه شد. جداسازي اثر پيچش را در سازه به ميزان قابل توجهي كاهش مي دهد. جانمايي جداساز و ميراگرها به گونه اي تنظيم شد تا در هر خروج از مركزيت جرمي، مركز سختي و ميرايي سيستم جداسازي در گام هاي 5% درصدي روي محوري كه از مراكز جرم مي گذرد تغيير كند. سپس پاسخ تغييرمكان روسازه و زير سازه در تمام اين حالت ها تحت 7 شتاب نگاشت منتخب مطالعه و با هم مقايسه شدند. در واقع هدف از مطالعه جانمايي جداسازها و ميراگرها، بهينه كردن تغييرمكان هاي روسازه و زيرسازه به صورت همزمان است، به گونه اي كه جداسازي به بهترين نحو پاسخ هاي سازه نامتقارن جرمي را به سازه متقارن نزديك كند.واژه هاي كليدي: سازه هاي نامتقارن جرمي، جداساز لاستيكي با هسته سربي، ميراگر ويسكوز غيرخطي، تحليل ديناميكي غيرخطي، سازه جداسازي شده

Study of the behavior of steel structures with basic seismic isolator and damper under asymmetric effect of Mass

  Historic bridge bridges are of great artistic value for humanity, and their historical architecture reflects the cultural identity of peoples of that time. Over the centuries, these structures are still stable and serviceable at risk for natural hazards such as earthquakes, floods, fires, wars and the growing population of the world. The bridge studied in this study is the old bridge. This bridge is one of the national Iranian and archeological works of Kermanshah Province which is located on the eastern border of Kermanshah, located on the Gharasso River, as a way of communicating the villages of Faramans Drood in entering Kermanshah. The bridge was constructed in the Sassanid period and was rebuilt in the current Safavid period, with six spans, about 188 meters in length, 9 meters in height, and 8.6 meters in height, including the crown of the bridge. The foundations of this bridge are hexagonal, the inner part of which is made up of lime sandstone and lime sandstone, and is surrounded by rectangular cubic stone blocks. At the front of the stands, opposite to the flow of the droplets of the triangle is a shape.

<  gt;ارزيابي تاثير مقاوم سازي اتصالات تير -ستون با ورق FRP در پارامترهاي رفتار ديناميكي قابهاي بتن مسلح</P>