Hamid Toopchi-Nezhad

     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

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.   

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:

The dynamic characteristics of structures depend on many of its details and the properties of materials. It is not possible to consider all conditions for computational models, and mostly software and design code,s use simplifying assumptions that may make the results far from reality. One of the structures used throughout the country is corrugated masonry structures, which unfortunately design regulations such as the 2800 standard did not pay much attention to these structures and only provided calculations with prescriptive methods. One of the things that plays a key and primary role in the design and calculations of the structure is the determination of the periodicity of the structure, which in the existing regulations and standards of the country is only in code 376, which is dedicated to the seismic retrofit of these structures. That this equation is significantly different from the results obtained from this research regarding the periodicity of the studied structure.    In the current research, which is dedicated to the construction of a forced vibration device and conducting physical tests on a part of Razi University Faculty of Engineering, we have determined the time of the main periodicities of the structure in the north-south and east-west direction, we have also used Ambient vibration testing. For this purpose, we first made a small sample of the vibration device based on the initial assumptions, and after observing the performance of the device, we proceeded to make the main sample of the device. The results show that the results of these two tests are in good agreement with each other The main device made includes a three-phase electric motor with a power of 1.5 horsepower, which is capable of controlling the speed of the device by a single-phase to three-phase converter connected to it. We used grade 8 roll bolts to install the device on the ground, and we used epoxy resin for proper connection and adhesion of the device to the ground through the bolts. We have compared the obtained results with the relations of the    regulations, and a significant difference has been observed. The accelerometers used are MEMS accelerometer and PDER data logger.   

   Investigating the seismic behavior of frames braced with CFT columns

  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.

  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 prevalence of frequent earthquakes throughout the world and the extensive human and financial damage caused by this phenomenon have prompted many researchers to explore ways to reduce this damage. Numerous systems have been employed to mitigate the aforementioned damage, among which seismic isolators can be considered one of the most important. Fiber-reinforced circular isolators represent a novel type of seismic isolator composed of alternating layers of elastomers and fiber fabrics. Utilized in an unbonded (non-connected) application, these isolators were placed above the foundation and below the superstructure, successfully isolating the superstructure from ground motions during an earthquake event. In an unbonded application, shear forces are transferred to the isolator through friction between the isolator’s contact surfaces and its contact supports. When the isolator is subjected to a lateral force, it undergoes a pseudo-rolling deformation, resulting in a nonlinear force-displacement curve. Consequently, the existing analytical relationships for traditional elastomeric isolators cannot be generalized to this type of isolator. In the isolator design process, determining the lateral stiffness under the influence of lateral forces is of particular importance. In the literature, only one analytical relationship has been proposed for this type of isolator, which, according to the investigations conducted in this thesis, does not provide a suitable approximation of the lateral stiffness in many cases. In this dissertation, not only has the existing relationship been modified, but also novel analytical correlations, which have been calibrated utilizing the outcomes of finite element simulations of fiber-reinforced circular isolators for the purpose of generating their lateral force-displacement diagrams. To verify the accuracy of the suggested associations, the force-displacement curves were assessed by comparing them with the hysteresis loops obtained from four experimental laboratory specimens. The equations introduced in this study can effectively approximate the lateral stiffness derived from laboratory experiments on isolators, exhibiting an average accuracy of 20% for shear strains of up to 0.5, and improving to an average accuracy of less than 10% for greater strains. Consequently, these correlations have sufficient precision for utilization in the initial design stages of unconnected fiber-reinforced circular isolators.

   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,

Cracking in concrete is alimiting factor for the inelastic performance of the structure, so byconfinement the concrete, its strength can be increased. Due to the highcompressive strength of high performance concretes, it is one of the well-knownmethods in increasing the strength of structures that has always beenconsidered by researchers and designers. Due to the need to respond to somedesign issues and the lack of uniform design criteria in the regulations, inthis research, an attempt has been made to test high performance concrete(UHPC) and by incorporating confinement conditions, compressive strength andstress diagrams. The aim of this thesiswas to experimental investigation the compressive behavior of ultra-highperformance concrete confined with FRP. For this purpose in this research, atfirst, reliable sources and new articles have been studied and reviewed. In thenext step, based on reliable sources, the mixing plan for normal concrete andhigh performance concrete (UHPC) is prepared. In the final step, 20 cylindricalsamples with different confinement conditions were subjected to compressiveloading and their stress-strain diagrams were evaluated.The results of thisthesis shown that, the ultimate strength of the third pattern was higher in thesample with NC concrete. Therefore, that in samples N25L1P3 and N50L1P3,respectively, the ultimate strength was 14% and 59% higher than the referencesample (N). While the second pattern has the lowest ultimate strength.5- The ultimate strengthof the third pattern was higher in the sample with UHPC concrete. So that inU25L1P3 and U50L1P3 samples, the ultimate strength was 394% and 433% higher thanthe reference sample (N).Also, increasing thepercentage of confinement in samples has increased the dissipated energy. Thelowest dissipated energy is related to the reference sample (N) and is equal to3.77 Kn.m, and the highest dissipated energy is related to the N100L1 sampleand is equal to 24.88 Kn.M. In addition, among the samples with UHPC concrete,the lowest dissipated energy corresponds to sample U and is equal to 10.28Kn.m, and the highest amount of dissipated energy is related to sample U100L1and is equal to 44.42 Kn.m.  

One of the types of steelshear wall is the composite shear wall, which consists of a steel sheet and a layerof reinforced concrete. This type of shear wall is used in high and mediumheight steel structures to improve the performance of the structure and controlvibrations during earthquakes. On the other hand, one of the serious threats insteel pasture structures is fire. Therefore, the necessity of investigating thebehavior after fire in steel structures with shear walls is felt more thanever.After studying theprevious researches, the scientific gaps and scientific challenges wereidentified and based on that, the purpose of the research was determined. Themain goal of this research is to investigate the seismic behavior of thecomposite shear wall with reinforced concrete cover at different temperaturesin the first step and to compare its behavior with the shear wall withoutreinforced concrete cover in the second step. For this purpose, three types ofsteel frame, including steel frame without shear wall (reference specimen),frame with steel shear wall without reinforced concrete cover and frame withsteel shear wall covered with reinforced concrete were studied in the conditionsbefore and after the fire.   Thetemperatures selected in this research are 25, 350, and 700 degrees Celsius,and the numerical models are subjected to cyclic loading, and the seismicbehavior, including the ultimate strength, energy dissipated, is compared andinvestigated. Also, the thermal stress caused by the fire is also evaluated.The results of thisresearch show that at all temperatures, the composite steel shear wall hasbetter seismic behavior than the steel shear wall, so that at 25 degreesCelsius, the ultimate strength of the frame with steel shear wall and the framewith composite shear wall It is 12.8 and 24.6 times of the reference sample(steel frame without steel shear wall), respectively. As a result oftemperature increase from 25 to 700 degrees Celsius, in the frame with steelshear wall, the ultimate strength has decreased from 483 to 11 tons, while inthe frame with composite shear wall it has decreased from 925 to 124 tons.Also, the presence of reinforced concrete cover on the steel sheet at alltemperatures has increased the cumulative dissipated energy. In other words,the presence of reinforced concrete coating on the steel sheet has protectedthe frame with shear wall against fire.  

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.

  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

   با وجود ظهور تكنولوژي هاي نوين ساختماني، نوع و تركيب ديوار همواره محل بحث مشاوران و فعالان صنعت ساختمان مي باشد. مؤلفه هايي مانند مقاومت در برابر فشار باد، تاثير وزن ديوار بر اسكلت و رفتار آن در زمان وقوع زلزله و به تبع آن كاهش تلفات انساني، مقاومت در برابر حريق، ميزان جذب صوت، ميزان عايق حرارتي، سرعت اجرا و... همواره از چالش هاي ساختمان سازي بوده است. در اين تحقيق(آزمايش) هدف اين بود با توليد فايبر سمنت برد به روش پرسي ضمن كوتاه كردن خط توليد و همچنين آسان كردن روش توليد، هزينه توليد را با حفظ مشخصات نسبت به روش   هات چك   به ميزان قابل توجهي كاهش داد همچنين در اين   پژوهش صحت سنجي استفاده از شيشه   و مو به عنوان الياف و جك هاي 30 و 10 تني جهت پرس كردن در توليد صفحات سيماني مورد بررسي قرار گرفت. جهت ساخت نمونه هاي مختلف   فايبرسمنت برد، از سه مصالح ماسه، پودر سنگ و پوكه معدني بصورت جدا همراه با سيمان، آب ، الياف مو و شيشه استفاده شد كه نتيجه كلي بدين صورت بود كه استفاده از مو به عنوان الياف باعث كاهش مقاومت خمشي صفحات سيماني مي شود و الياف شيشه مقاومت خمشي صفحات   سيماني   را افزايش مي دهد. نتايج آزمون   تعيين مقاومت خمشي بر روي آزمونه ها، نشان مي دهد كه صفحات ساخته شده با تركيب سيمان، پوكه معدني رد شده از الك 14 والياف شيشه   ساخته شده با دستگاه پرس 30 تني الزامات استاندارد   EN 12467   را در رده مقاومتي 2 (مقاومت خمشي 8.26 مگا پاسكال در شرايط خشك) و صفحات ساخته شده با سيمان، پودر سنگ رد شده از الك 30 و الياف شيشه ساخته شده با دستگاه پرس 30 تني الزامات استاندارد EN 12467   را در رده مقاومتي 3( مقاومت خمشي 10.3 مگاپاسكال در شرايط خشك ) برآورده مي كنند.               

    Preparation of nanocompositemembranescontaining zinc oxidenanoparticle modified with herbal oils for application in membrane distillation

استفاده از دانه هاي لاستيك توليد شده از تايرهاي ضايعاتي و نيز پودر شيشه حاصل از بازيافت شيشه ضايعاتي به عنوان جايگزين بخشي از مصالح (سنگدانه يا سيمان) در توليد بتن يك راه پايدار براي كاهش آلودگي محيط زيست همچنين كاهش مصرف منابع طبيعي و آلودگي هاي ناشي از توليد آن مي باشد. همچنين با توجه به افزايش توليد لاستيك   وشيشه به علت افزايش تقاضا و مشكلات عديده در راه بازيافت اين مواد، توجه به اين امر لازم و ضروري مي باشد. در اين تحقيق سعي مي شود از خرده لاستيك دانه بندي شده به عنوان بخشي از سنگدانه ريز، جايگزين شده و ميزان بهينه اين مصالح در بتن به جاي جمع آوري و يا سوزاندن آنها، تعيين شود. همچنين تاثير استفاده از پودر شيشه نيز به عنوان يكي ديگر از مواد بازيافتي در بتن مورد بررسي قرار گرفت . بعلاوه، تلاش شد كه با بهره گيري از ماده شبه سيماني متاكائولين، ميزان كارايي آن ارزيابي شده و همچنين مصرف سيمان كاهش يابد. هدف اصلي تحقيق ساخت بتني مناسب از نظر زيست محيطي و همچنين تامين­كننده الزامات آئين نامه­اي بود. براي اين منظور پارامترهاي مربوط به خصوصيات مكانيكي ازقبيل مقاومت فشاري، كششي، خمشي، تعيين منحني هاي تنش – كرنش و جذب آب در بازه زماني نيم، يك و 24 ساعته ارزيابي شد. كاهش در وزن، مقاومت فشاري 7 و 28 روزه نمونه هاي حاوي خرده لاستيك مشاهده شد. كاهش وزن در نمونه هاي 7 و 28 روزه به ترتيب به طور ميانگين 16/2 و 02/6 درصد مي باشد. با اين حال ميزان افزايش مقاومت فشاري 28 روزه نسبت به 7 روزه در نمونه هاي حاوي متاكائولين نمود بيشتري داشت. خرده لاستيك موجب كاهش مقاومت كششي و خمشي نمونه ها نيز شد. تاثير متاكائولين به تنهايي در بهبود خصوصيات مكانيكي بتن حاوي خرده لاستيك، بيشتر از پودر شيشه بود و مي توان انتظار داشت تاثير مثبت متاكائولين در سنين بالاتر در افزايش مقاومت فشاري چشمگير باشد.   

 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%

   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.

  The presence of Iran on the Alpide earthquake belt highlights the need for a study on the behavior of structures and their robust design. Therefore, researchers are seeking to improve seismic behavior of buildings using different methods. One of these methods is the use of composite concrete columns (CFT). In this research, the aim is studying the effect of these kind of columns on the seismic behavior of steel structures. The results of this research can show the effectiveness of this system.In this research, lateral displacement diagrams of the structure in relation to time in seven earthquakes and with different systems of lateral load resisting, including moment resistance frame, x bracing and steel plate shear wall are presented. In addition, lateral displacement diagrams of the structure are presented in relation to the time of a type of lateral lateral load resisting system in different earthquakes.In this study, the seismic behavior of a steel structure with a lateral load resisting system of steel plate shear wall and concrete composite columns and compared to steel structures with bracing systems and bending frame with ordinary columns will be considered. For this purpose, three structures of 10-story steel structures with a steel slab loading system, a 10-story steel building with a bracing system and conventional columns, and a 10-story steel building with a moment resistance frame and conventional columns will be analyzed.

  كف هاي طاق ضربي متشكل از طاق هاي قوسي شكل بنايي با دهانه حدود يك متر هستند كه بارهاي ثقلي را به تكيه گاه هاي خود (تيرچه هاي فولادي) منتقل مي نمايند. تعداد قابل توجهي از كف هاي طاق ضربي در ساختمان هاي موجود   بدليل ناكافي بودن ممان اينرسي تيرچه هاي خود تحت بارهاي   پياده روي داراي مشكل ارتعاشات قائم بيش از حد هستند. با اين حال، مشكل ارتعاش تنها محدود به اين نوع كف نبوده و در ساختمان هاي جديد نيز   كه تمايل به استفاده از دهانه هاي بزرگ تر، كاهش پارتيشن ها و تيغه ها در ساختمان، و كاربرد مصالح سبك رايج است، كم و بيش مشكل ارتعاشات آزار دهنده كف هاي سازه اي مطرح مي باشد. در ساختمان هاي اداري جديد با توجه به   پيشرفت فناوري،   بسياري از كمدهاي مدارك و قفسه هاي بايگاني با كامپيوتري روميزي جايگزين شده اند. بنابراين، علاوه بر بارهاي مرده كف (بدليل سبك سازي)، بارهاي بهره برداري نيز نسبت به گذشته كاهش قابل توجهي يافته اند و   ميرايي موثر كف كاهش يافته است. اين عوامل سبب ايجاد ارتعاشات سازه اي بيش از حد در كف هاي مذكور شده است كه در درجه اول موجب سلب آسايش ساكنين شده و در بعضي موارد سبب اختلال در عملكرد تجهيزات حساس نصب شده در سازه مي گردد. يكي از راه حل هاي موجود جهت كاهش   ارتعاشات   افزايش سختي و فركانس سازه كف   با افزايش تعداد ستون ها و يا تغيير مقاطع تيرها و . . مي باشدكه اين امر نيازمند صرف زمان و هزينه زيادي است. به علاوه در اغلب موارد محدوديت هاي   معماري عمدتا مانع اين راهكار ميشوند. راه حل ديگر در كاهش ارتعاشات افزايش ميرايي موثر كف با استفاده از انواع ميراگرهاي   الحاقي مي باشد. در اين پايان نامه براي كاهش ارتعاشات   دو كف سازه اي مختلف (الف: طاق ضربي و ب: عرشه فولادي با ورق هاي موج دار) تحت بارگذاري هاي مختلف پياده روي   از ميراگرهاي جرمي تنظيم شونده ويسكوالاستيك استفاده بعمل آمده است. مدل سازي ها با استفاده از نرم افزار آباكوس انجام شده است.   مدل اجزا محدود ميراگرهاي مورد نظر براساس نتايج آزمايشگاهي ارتعاش آزاد پيشين كاليبره شده است. سپس، جانمايي مناسب ميراگر، با هدف دستيابي به بيش ترين كاهش در ارتعاشات تير، با مدلسازي ارتعاشات تيري با فركانس طبيعي 52/4 هرتز و كاربرد ميراگر   در 8 حالت مختلف مورد بررسي قرار گرفت. در ادامه با مدلسازي يك كف طاق ضربي و نيز يك كف عرشه فولادي داراي ارتعاشات بيش از حد مجاز، تاثير   ميراگرهاي با نسبت جرمي 1% ، 2%،   و 3% در كاهش ارتعاشات مورد بررسي قرار گرفت.   ارتعاشات كف هاي مذكورتحت اثر 6 بارگذاري پياده روي و 3 بارگذاري دويدن با فركانس هاي تحريك 5/1،   2، و 3 هرتز   بررسي شده است. نتايج اين تحقيق نشان مي دهد در حالتي كه ميراگر در وسط دهانه و موازي با تير قرار مي گيرد بيش ترين كاهش در شتاب حداكثر ايجاد شده در كف به دست مي آيد. چنانچه به هر دليل   امكان نصب پايه ميرا گر ها در وسط دهانه تيرچه كف ميسر نباشد، ميراگرها را بايد در طرفين مركز تيرچه بگونه اي نصب كرد كه جرم انتهايي آنها متمايل بسمت داخل دهانه تيرچه قرار گيرد تا كاهش حداكثري ايجاد شود. بر اساس مطالعات اين پايان نامه   ميراگرهاي جرمي تنظيم شونده مورد بررسي   قادر به كاهش ارتعاشات هر دو كف سازه اي تا   حد مجاز تحت اثر   بار هاي پياده روي   بوده و براي بارگذاري ناشي از دويدن تا 80% ارتعاشات را كاهش   مي دهند.  

  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

بررسي تاثير ويژگي هاي تسهيلات خياباني بر شاخص هاي ايمني در مناطق شهري ، مطالعه موردي : ايلام

  Determination of residual stresses and distortion infriction stir welded 2024 Aluminum alloy by ALEnumerical simulation

هستند.  

Performance evaluation of unbounded fiber-reinforced elastomeric isolators against wind

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

بررسي عملكرد ميراگرهاي جرمي تنظيم شونده ويسكوالاستيك 

مقاوم سازي قاب بتني خمشي با استفاده از ميراگر اصطكاكي

بررسي تجربي آزمايشگاهي مقاوم سازي دال هاي تخت بتن مسلح در برابر برش پانچ

بررسي آزمايشگاهي بتن ساخته شده از مصالح بازيافتي پلي اتيلن سنگين به عنوان سنگدانه

  AbstractBitumen and asphalt self-healing is present as an intrinsic property in bitumen and asphalt, and asphalt and bituminous asphalt researchers seek to recognize, expand, and ultimately make practical use of this feature. Self-resiliency is different from thixotropy, and unlike thixotropy, it is related to the repair of crack cracks caused by the loading and it can be considered as a reversible fatigue phenomenon. Self-resurfacing depends on factors such as temperature, rest time, crack width and features of bitumen and asphalt, and is activated by temperature rises, so scientists are looking for the best and most economical way to create heat in asphalt, from The suggestion of these innovative methods can be found in the method of heating through electromagnetic waves and the heating method through microwave waves. Researchers have used various methods to assess the quality and quantity of self-defense, most notably fatigue-based tests, rupture tests, and non-destructive tests.In this dissertation, the ability to repair three types of modified asphalt with additives with a non-additive asphalt type (for comparison) was investigated through rupture-based experiments (three-point bending test), for which the semi-cylindrical samples The Marshall was repaired by a three-point bending device and then warmed up by microwave irradiation and after a 24-hour period. After repair, the samples were restored by three-point bending test to determine the degree of repair. On the other hand, the temperature created on the surface and in the asphalt samples was investigated and according to the results of the experiments, the asphalt made with two The additive of nanosecotherm and Fortah fibers has the highest initial resistance and secondary resistance to the other three types of asphalt, and the uniformity of temperature in this type of asphalt was more evident than other asphalt.

  Today, despite significant advances in construction, many of the existing structures against earthquakes do not function properly. The inappropriate seismic behavior of these structures can lead to many fatal and financial damages. In order to prevent such damages, an appropriate and economical solution is to retrofit existing buildings.Considering the damage caused by earthquake in prone to earthquake, it has been observed that joints are one of the most important and vulnerable areas in concrete structures. Therefore, due to the importance of joints in the proper seismic performance of the structure, the behavior of concrete joints and their retrofitting methods against earthquakes has been investigated.In this study, the reinforcement of the external connections of the beam to the reinforced concrete column was investigated using FRP sheets and steel jacket. In this regard, for different makeup of FRP and steel jackets and for three concrete grades 25, 30, 35 Mpa, various parameters such as strength, hardness, energy absorption and ductility were calculated and evaluated.

  The lightweight steel frame (LSF) structure, is a building system used primarily for short-term and intermediate-level buildings. Due to its plenty of advantages compared to other existing systems in construction, the use of this system is increasing. In this structure, cold formed steel sheets (CFS) are used to make thin-walled steel sections. These sections are galvanized steel sheets, which are formed using cold forming. In this system, CFS beams and columns are used as barrier members. The beams used in this system are often made up of 0.5 to 3 mm, which, Because of their low thickness, they are prone to buckling. This geometric feature affects their load-bearing capacity and makes it impossible to can not to use the load bearing capacity of the sections well. Therefore, using the method that increases the resistance buckling of beam, it can be used the load-bearing capacity more efficiently.An ideal method for achieving this goal is to create a bracing for the CFS beams by casting concrete around the web. the concrete can provide bracing for beam and improve the buckling resistanae of it. For this purpose, the ultra-lightweight-concrete encased cold-formed steel beams have been investigated. This concrete has a slight compressive strength and is often used as an insulating or filler material, but it has now been found to be structural performance.In this study, using finite element analysis, polystyrene aggregate concrete (PAC) encased CFS beams under four-point bending loading have been investigated. For this purpose, 2C and 2U cross-section beams with different geometric dimensions were modeled and investigated. The results showed that, using of PAC can provide full bracing for the steel beams and increase their ultimate strength capacity level by 43%. In addition, due to the lightness of this concrete, A slight load is added to the weight of the structure and the advantage of the lightness of the LSF structures is maintained.

Abstract Building frames are usually filled in the periphery and middle of the building with masonry walls as internal or external walls, which makes the difference between such frames with empty frames. These type of walls are said to be infill panel and to the interaction of the frame and the infill panel said to be composite frame or filled frame. In the steel frames with saddle connection, as in the other types of building frames, there are infill panels that are usually made of masonry materials and their effect on structural analysis is ignored. However, in the event of intense and moderate earthquakes, the creation of interaction forces between the environmental frame and infill panel increases the bearing capacity of the structure. This interaction can be beneficial or harmful for the structure.   In many studies, researchers have compared the behavior of the composite frame with empty frame, which in part of   this thesis this topic has been reviewed, and few have exploring the comparison of the composite frame behavior to the infill panel. Therefore, an attempt has been made to examine this topic in another part of the thesis. Fore numerical modeling, the ANSYS software has been used. The masonry wall is modeled in macro approach with using laboratory test results. In the macro modeling that was used in this study, the masonry wall is assumed to be homogeneous and with equivalent mechanical properties. Modeling in this way is simple and the calculations is also very less than micro modeling.In fact, the stress-strain curve of the masonry wall and a conventional properties such as elasticity modulus and Poissons ratio of the masonry and etc will be able to model the nonlinear behavior of the masonry wall. The nonlinear static analysis is used for analysis of masonry wall. First, by comparing the result of numerical modeling with the experimental results, the correctness of the selected method for controlling the masonry infill is controlled and then the steel frames of a one story-one bay and two story-two bay with rigid saddle connection are modeled in the software. The interaction between the steel frame and masonry infill is modeled using contact elements with Mohr-coulomb behavior. Comparing the results of numerical simulations with experimental results, it shows that numerical model in three-dimensional simulation behavior of unreinforced masonry wall and rigid saddle connection has a good ability. In this thesis, In addition to modeling, increase percent of stiffness, increase percent of ultimate strength and the ductility changes of the composite frames relative to the empty frame with different yielding stresses and single masonry infills with different compressive strengths, the intensity stress distribution, the intensity elastic strain distribution composite frames and empty frame and the cracking pattern of masonry infill in the composite frames are also considered. Finally the results, is an increase in the stiffness and final strength and the ductility changes of the composite frames in comparison to the empty frame and single infill panel and the negative effects of the infill panel on the members of the perimeter frame caused by the interaction of the frames and infill panel.  

  In this study, frames with concrete-filled steel tubular (CFST)   columns with sandwich panels were used. The CFST columns, due to the many benefits that it has, are propagation every year. The advantages of steel and concrete are well-known, concrete with good compressive strength, reasonable price for other materials and considerable resistance to fire burning, and steel is a material with high ductility and high strength. The combination of these two materials is a composite material with good properties. In CFST columns, the existence of a steel tube makes it more confinement to the concrete inside it, as well as the existence of concrete inside the steel, preventing the local buckling of the steel and thus increasing the load capacity of the column. Sandwich panel as an effective member is widely used in industrial buildings and structures. The sandwich panel has a good flexible and relatively low weight, with a central core and outer layers attached to the sides of the core. In this study, numerical models have been used to investigate the effect of different parameters on stiffe   , ultimate strength and energy dissipation of the CFST frame with the sandwich panels intermediate. In order to verify the numerical modeling, several experimental tests Wang-2017 (reference 3) were modeled using ABAQUS fainant element   software and the acceptable acceptance of the results of the analyzes confirmed the validity of the modeling. . The results showed that the use of the sandwich panel intermediate reinforced the ultimate strength, structural stiffness and energy dissipation considerably

  Unbonded fibre-reinforced elastomeric isolator (U-FREI) is a relatively new seismic base isolator in which fiber layers are used as reinforcement to replace steel shims as are normally used in conventional isolators. Further, the top and bottom end steel connector plates of conventional isolators are also removed. In general, the horizontal response of U-FREI is nonlinear because of reduction in contact area due to rollover deformation and reduction in shear modulus of isolator under large deformation. Thus, evaluation of horizontal stiffness of U-FREI is a challenging problem. The unbonded application leads to rollover deformation that results in advantages such as decreasing the demand tension stress between internal layers and increasing efficiency of the bearing as a seismic isolator. Most of the previous finite element analysis studies on FREIs only have addressed the simulation of the monotonic behavior of this type of isolators. In this thesis, the main objective is to simulate the laterl load-displacement hysteresis loops of U-FREIs. The combination of an effective hyperelastic behavioral model in large deformations with viscoelastic behavior, the hyper-viscoelastic model will be produced that has the ability to consider the time dependency in the finite element analysis of isolator. The hyperelastic parameters are evaluated by curve fitting of theoretical curve to three uniaxial tension test of elastomer dumble-shaped specimens. The viscoelastic behavior is simulated using the Prony Series, and its parameters are determined by using the Nelder-Mead simplex method optimization algorithm, and the cyclic experimental results. The results show that the use of viscoelastic material model in conjunction to hyper-elastic material model leads to the effective simulation of horizontal stiffness and hysteresis load-displacement loops of FREIs. As another component of this thesis, The lateral response of isolator under various vertical compression stresses is studied using the finite element model that is developed in this study. Results show that both the effective horizontal stiffness, and equivalent viscous damping are increased by increasing vertical compression stress.

Many systems have been used for this purpose including seismic base-isolators which are among the most important ones. In this method, structures move isolated from the ground by placing a flexible lateral structure between the structure and the foundation. Isolators have several types, the most common of which are Steel Reinforced Elastomeric Bearings (SREBs). These isolators are made of intermittent and bonded  elastomer layers and reinforced steel plates. Such isolators currently lack required economic justification for many conventional structures due to high expenses. In the last fifteen years, new elastomeric isolators have been developed called Fiber Reinforced Elastomeric Bearing (FREBs). In these isolators fiber reinforced layers are used, instead of heavy metal plates, to control the lateral strains of the elastomeric layers and to provide the necessary hardness along the vertical axis. In terms of bonding to the bearing, the isolators are categorized into three groups of "bonded", "partially bonded" and "unbonded". In unbonded mode, isolators lack the upper and lower steel plates, which reduce the expense and weights of isolators. In unbonded mode, no mechanical connection is made between bearing surfaces. In this situation, shear force is transmitted through friction at contact surface of the isolator with the bearing. These detachers undergo a unique deformation under rollover lateral displacement, which leads to the contact of the initial vertical surface of isolator with the upper and lower bearing of the isolator.   Following a rollover deformation, the effective lateral hardness of the isolator has been reduced further, which means increasing the vibration isolation period and, in fact, increasing the seismic isolation efficiency. In this research, the finite element analysis has been used to model the behavior of force- one-way lateral deformation of Fiber Reinforced Elastomeric Bearing (FREBs) isolators. The modeling of these isolators is conducted in 3D format using MCS MARC finite element software. Providing a 3D model of Fiber Reinforced Elastomeric Bearing isolator with material specifications and geometric dimensional scaled with real dimensions in finite element analysis allows us to avoid some costly and time-consuming laboratory studies. The focus of this thesis is on the modeling of three-dimensional finite elemental behavior of the Fiber Reinforced Elastomeric Bearing circular isolators. Research literature in this area has nothing to say. In the analysis, the effect of the geometry of the rubber layers on horizontal and vertical responses of elastomeric isolators was studied. The effect of thickness is investigated by (

بررسي منحني ظرفيت سازه هاي داراي ستون بتن پر(CFD)

    تحليل رفتار مكانيكي ميكرو- سازه‌ها به‌‌عنوان يكي از اجزاي اساسي سيستم‌هاي نانو-ميكرو الكترومكانيك از اهميت خاصي در بين محققين رشته مهندسي مكانيك برخوردار مي‌باشد. در اين راستا، ميكرو‌-تيرها در سيستم‌هاي ميكرو-نانو مانند: ميكرو‌پمپ‌ها، ميكرو‌آينه‌ها و ميكرو‌سنسور‌ها نقش مهمي را ايفا مي‌نمايند. با توجه به مطالب ذكر شده تحليل رفتار ميكرو سازه‌هاي ساخته شده از مواد تابعي براي طراحي دقيق و مناسب از اهميت فوق العاده‌اي برخوردار مي‌باشد. از مهمترين پارامترهاي طراحي داده‌هاي مربوط به آناليز ارتعاشات آزاد و اجباري سازه هاي مي‌باشد. همچنين براي انجام تحليل مناسب و حاصل شدن نتايج دقيق‌تر بايد همزمان از يكي از   تئوري‌هاي محيط پيوسته غيركلاسيك و مدل تغيير شكل برشي استفاده نمود. هدف اصلي پايان نامه تحليل و بررسي تاثير گراديان حرارت بر روي تير كامپوزيتي تقويت شده با نانو لوله هاي نيتريد بور مي­باشد.كه تير موردنظر بر اساس تير تيمو شنكو مدل سازي شده وقوانين حاكم بر اين تير براي حل اين مساله كمك گرفته شده است.در اين پايان نامه مقدار خيز وتنش و كرنش   محوري و برشي بررسي شده است وبا افزيش درصدجرمي نانولوله هاي نيتريد بور مقدار خيز تير كاهش يافت همچنين تاثير پارامترهاي همچون، نحوه‌ي توزيع نانولوله در راستاي ضخامت تير، شرايط مرزي مختلف ونسبت لاغري تير بر روي جابه‌جايي و تنش بررسي شده است و نتايج بدست آمده نشان مي‌دهد كه تغيير هر كدام از اين پارامترها تاثير بسزايي بر روي جابه‌جايي و تنش دارد.                 واژگان كليدي: مكانيك محيط پيوسته غير‌كلاسيك، تير، تئوري تنش برشي ،گراديان حرارتي.

در اين پايان نامه به كمك رزوناتورهايTشكل ونيمدايره اي يك فيلتر پايين گذر طراحي، شبيه سازي و ساخته شده است. اين فيلتر داراي فركانس قطع GHz34/1است و همچنين تيزي آن از سطح dB3 تا dB40 برابر GHz41/0 است. همچنين باند قطع اين ساختار از فركانس GHz68/1 تا GHz20 مي­باشد كه نشان مي­دهد فيلتري با پهناي باند قطع عريض طراحي شده است و سطح حذف هارمونيك در باند قطع اين فيلتر برابر dB20 است. اندازه اين فيلتر برابر 9mm2/15 ×3/9مي­باشد كه با اين خصوصيات، اين فيلتر از ضريب شايستگي67954 بهره مي­برد. لازم به ذكر مي باشد كه در اين پايان نامه، فيلتر پايين گذر طراحي شده به چند رزوناتور   تقسيم شده و اين فيلتر ساخته شده است كه مشاهده مي شود پاسخ ساخت و شبيه سازي تطبيق خيلي مناسبي مي­باشند.  كلمات كليدي:رزوناتور،­فيلتر پايين گذر، اندازه كوچك، فركانس قطع.

Self-repairing is among the principal foundations of biological neural networks, upon which, adjacent synapses undertake functions of defected synapses to avoid disturbances in the network function, ending up compensating the incurred error. In the present research, a self-repairing analogue circuit is designed using an astrocyte-neuron relationship. The designed circuit is based on a software model of an astrocyte-neuron network with proven ability to detect errors and undertake self-repairing. The results obtained of the proposed circuit show that, when an error occurs in the synapses associated with a neuron, the currents of healthy synapses of the same neuron increases. This increase is made by receiving a feedback from adjacent astrocytes. This process maintains the network function and compensating the incurred error in the network. To the best of our knowledge, this is the first report to present a neural network-based analogue circuit with self-repairing capability considering the effect of astrocytes. In this research, the proposed circuit was designed and simulated in HSPICE software using standard 0.35 ?m CMOS technology.

راه‌ها به منظور دسترسي يا حمل ونقل احداث مي‌گردند. نظر به اين كه شرايط محيطي همچون كوه، تپه، دره، تقاطع، تغيير مسير به نقاط موردنظر و ... در راه اعمال مي‌شود، بنابراين راه ديگر نمي‌تواند فقط يك مسير مستقيم باشد، بلكه به شكل‌هاي هندسي متفاوتي درمي‌آيد. به همين دليل است كه نياز به يك طرح هندسي مطلوب احساس مي‌شود. امروزه افزايش ايمني راه ها به يكي از معضلات مهم كشورهاي در حال توسعه در بخش حمل و نقل و اقتصاد تبديل شده است و از اين رو در سال هاي اخير تحقيقات قابل توجهي در سراسر دنيا براي درك ارتباط بين تعداد تصادفات، حجم ترافيك عبوري، مشخصات هندسي مسير و عوامل محيطي در قالب مدل هاي پيش بيني تعداد تصادفات انجام پذيرفته است. اين مدل ها ابزاري قوي در تحليل تصادفات محسوب مي‌گردند كه در شناسايي و تحليل نقاط حادثه خيز در جاده هاي برون شهري به كار گرفته مي شوند. استفاده از مدل هاي پيش بيني كه بر اساس روش هاي دقيق آماري و اطلاعات راه ها و تصادفات بدست مي‌آيند، نه تنها در ارزيابي اصلاحات هندسي و مديريتي راه موثر واقع مي شوند بلكه شناسايي نقاط حادثه خيز را آسان و قابل بررسي مي نمايد. كمربندي شهرستان ايلام همه ساله مسيري اصلي براي تردد زائران حسيني به سمت مرز مهران واقع شده كه بر اهميت مطالعات بر روي مسير كمربندي شرقي مي افزايد. در اين تحقيق تلاش شده است با استفاده از بانك اطلاعاتي شهرستان ايلام، داده‌ها جمع آوري و مدلي ارائه شود، تا ميزان تاثير پارامتر هاي موثر طرح هندسي و همچنين كاربري هاي اطراف مسير بر ايمني جاده هاي برون شهري بررسي شود. در كنار جاده ها زمين‌هايي كه وجود دارند با كاربري‌هاي متفاوت مي‌باشند كه تأثير آن بر ايمني بررسي خواهد شد. در اطراف جاده ها مي‌تواند مكان هاي متفاوت با كاربري‌هاي مختلف وجود داشته باشد كه باعث تعامل و رفت و آمد مراجعان مي شود. اين رفت و آمد مراجعين سبب بروز عواملي چون ترافيك شده كه با توجه به راه طراحي شده و ويژگي هاي طرح هندسي راه مي‌تواند سبب ايمن بودن طرح يا بروز تصادفات رانندگي شود كه بايد براي مسيرهاي خطرناك يا پرتردد تعابير مهندسي لازم را در نظر داشت. بدين منظور متغيرهاي تاثير گذار و وابسته كه ايمني جاده مي باشد جهت پردازش آناليزهاي لازم انتخاب خواهد شد و بررسي هاي لازم و شرح ارتباط ميان ايمني جاده يا متغير وابست? تحقيق حاضر با ويژگي هاي طرح هندسي راه و كاربري هاي زمين هاي اطراف جاده صورت مي‌پذيرد سپس در ادام? بررسي حاضر به ارائه مدلي با بسط موارد ايمني راه، كاربري اطراف جاده و طرح هندسي پرداخته خواهد شد بطوريكه بصورت موازن? سه پارامتر را دربرگيرد. سپس بر اساس آمارگيري و برداشت‌هاي ميداني در محورهاي كمربندي شرقي ايلام و تكميل اطلاعات لازم، مدل كاليبره و ارائه خواهد شد.  

تحليل تكيه گاه بتن آرمه اي ميراگرهاي ويسكوالاستيك متصل به ديافراگم طبقات

  The destructive effect of confined water on the blast response of RC slabs

  Progressive collapse is the event that if occurred may be caused to irreparable disaster. Nowadays, different methods are suggested to resistance against progressive collapse that these methods are divided into the direct and indirect method. In indirect method due to approximation in the calculation, isn’t properly for this study. In direct methods, alternate path method is the excellent and complete method to evaluation the structure against progressive collapse. In alternate path method, a column is removed suddenly from the structure. By this method, standards are carried out independent of extreme loads like blast, earthquake, fire and construction or design error. In this study, to the evaluation of reinforced concrete structures against progressive collapse, alternate path method is used. In this research, a six-story reinforced concrete building with intermediate moment frame in both directions is considered. The dimensions of beam and columns and the number of bars are determined by ETABS2000. In this building, one-way joist running is used to floor systems. After building design, two external frames of the building is modeled in open system program OpenSees. Frames modeled in three manners. In a first manner, frame modeled without infill wall, then in a second manner, frame with infill wall without opening and finally in a third manner, with infill wall by considering 30% opening. In this thesis, six scenarios are considered for each frame that with considering of two frames and three manners of infill wall, 36 scenarios are performed. In this thesis, the nonlinear dynamic analysis is used to capture the real behavior of frames after sudden column removal. Push down analysis is performed for evaluation of the capacity of the frames after column removal. In push down analysis, the gravity loads are applied increasingly to frame until the frame is collapsed. In this study, it is obvious that in a higher level of frames, the potential of damage is increased. Using of one way joist running is concluded to increase potential collapse in bays that loads of floor system is carried to them. In addition to above mentioned, it can be said that infill walls can more considerable role in stiffness and resistant of frames. This effect is more be seen when the length of bays is increased or the infill wall hasn’t opened. Opening in infill wall can reduce considerable of frame strength; this reduction of strength can be limited to equal or less than of frame without infill wall.

  AbstractSoil-structure interaction effects of soil under the foundation of flexibility, relative vibrations between the foundation and the free surface arises. The inclusion of this effect and inertial forces can be a real shift system -Py-soil structures under seismic movements set free surface.Over the past three decades extensive research to characterize the soil-structure interaction effects engineering have been conducted. The results of this research in many earthquake regulations such as NEHRP, UBC, ATC,… come.Many construction requires the deep and wide excavation that the construction and operation may take several years. deep and wide excavation in an urban environment where the drilling location is surrounded by many building, it is important that the impact on the environment the vital challenge is investigation interaction between excavation and building during earthquake.Earthquake regulations have not studied this work. The aim of this thesis is investigation effect of adjust deep excavation on structural performance during earthquakeThe result for study Kermanshah hamyari building that adjust urban train excavation shown Increasing amounts of displacement, Increasing the period of the structure, Reducing the base shear.As a result excavation investigates adjacent structures is very necessary in the analysis.Key words: soil-structure interaction, deep excavation, base shear, period of first mode  

  Investigation that how Earthquakes Can effect on our structures made by human is very important for economical and safe design of the structures. By the previous research on the behavior of the structures it is obvious that a shear force acts at the base of structures during earthquake. Estimating a Reliable valu for base shear are very important to reduce structural damages caused be wind or earthquake. For the first time after the 1908 italy Earthquake engineers set it as 10% 0f structural weight. They changed it to 12.5% of structural weight in form of base shear.  By considering this provision structural performance was improved in later hazards and make structures after during.But structures show different behaviours against same earthquake.  Today millions of people live in structures made by Reinforced Concrete Coupled Shear Wall Systems. And some of most important structure like nuclear power plan, high rise tower and etc, are made in this way too. A coupled shear wall is a structural system made from to combined RC shear wall connecting by a beam named as coupling beam.  In this system thickness of concrete slab and shear wall are equal usually, for more rapid construction.  In many design Code such as the code and ASCE200 and UBC 1997 and regulation in turkey effect of earthquake force reduction factor in considered using ioss of the strength and ductility.  However, in none of the regulation , there is no way for calculating the behavior coefficient for those building that don’t have coloumn or girder and consisting ceiling and slab( tunnel form structure).vertical and lateral loads in tunnel form system are to lerated by the system.  In most cases, to access , and architectural elements or through ducts in the walls of the facility is a porter opening occurred in the structures of these systems proved to scientist.  The behaviour of such systems is entirely dependent on the geometry of the structure and behaviour of structures with different opening.  First a brief description on construction methods of this system was performed. Then some non-linear dynamic analysis on some models were performed by ABAQUS ver 6.14.3.  After that some smaller models made of walls and slabs modeled here in ABAQUS. For the sensitivity case study of the opening ratio on the behaviour of them were constand and only the opening ratio of the plan were different.  At final, after doing analyses curves were presented for the realative change of the behaviour.

  AbstractDue to the significant load carrying capacity of masonry wall, they were comprised the main construction materials in the past year. First, this materials were obtained by the hardening of mud on side of the grill and cooking ovens. Todays bricks were built based on this issue. At that time, it was used only because of its strength and availability, but with the passage of time and observing the behavior and performance of these materials in earthquakes and wind, the need to understand the exact behavior of these materials were felt more than ever.,Wood has been used since the beginning of history and due to its good tensile strength and economical and easy process there in its manufacturing and also help to protect the environment because of carbon dioxide that its stored in, is taken into consideration. Another advantage of wood are cheap cost and availability in the Cities and villages are underdeveloped.Masonry structure with timber framed is a structural system with high diversity and complexity. Limited analytical and experimental research has been done to detect seismic response on this structure. From the Bronze Age, this system was common in seismic areas. According to the behavior of masonry structures, the fundamental weakness of them against the earthquake, not lack of strength, But it is the lack of stiffness or plasticity. This weakness can be alleviated by reinforcement. Despite of the high shear strength of masonry structures, due to brittle behavior of materials, the improvement of performance of these structures for increasing in capacity and ductility is very important and the use of reinforcement elements such a member in order to eliminate disadvantages of these structures had historically been considered.

  Due to the development of appropriate methods for seismic retrofit and rehabilitation of buildings against seismic loads due to the vulnerability of masonry buildings that include a large number of buildings in the country is an important. One of the methods of retrofit and rehabilitation for unreinforced wall is use of steel bars with concrete coverage in one or both sides of wall. This steel gride is connected to the wall with steel nails. Implementing of such method increases the lateral loading capacity of wall, but also caused more cohesion of wall in integrity manner. In recent years, engineers implemented this method as an efficient and economical way for the most rehabilitation plans of the countries present masonry buildings. But since the lack of experimental information over these walls seismic performance and actions, which their designing generally based on the standards of concrete instructions or engineering judgment. According to the studies that have not been performed about the effect of steel nails in the reinforced wall. In this thsis first a pull-out test was carried out to place the steel rebar embedded in brick-mortar sample under tensile load. As the result of this test, bond strength, maximum tolerable tensile and displacement corresponding to the tensile load and load-displacement curve are obtained. Then, the experimental model was numerically simulated to obtain sliding, displacement, plastic strain, and the stress of the steel rebar and the brick-mortar sample. Second by using ANSYS17 software is investigated the effect arrengement of this steel nail on seismic performance of masonry walls with 10cm, 20cm, 30cm thickness in full-scale and small scale. The load – displacement diagram to one side wall on both sides of reinforced concrete with an experimental model has compared then the load – displacement diagram, displacement contour, and plastic strain for two side and one side reinforced wall in two forms with steel nails and without steel nails has compared. Finally, the steel nails force diagram is shown.

  A comparative study on horizontal stiffness solutions for unbonded – FREIs

  umerical Study Of the Effect of Local Change of Channel Width On Flow Pattern In Open-Channel Junction