@article{ author = {Attarzadeh, A. and Zarrati, A.R. and Shanehsazzadeh, A.}, title = {Flow Condition at Sudden Slope Change of Chutes}, abstract ={One of the important parts of many large dams is flood release chute spillway. Aerators are installed on chute spillways to prevent cavitation phenomenon under very high speed water flow. An aerator consists of a ramp providing a sudden slope change that separates water from the bed and permits air to mix with water. For the study of flow condition in aeration zone and for having an insight knowledge about the aeration, the study of flow condition on the ramp is a prerequisite. The change in the slope of the bed is common in spillways due to the change in the topographical slope and at the connection of the spillway and the stilling basin. In the present study, the flow condition at the place of sudden slope change was numerically simulated by FLUENT software. FLUENT is powerful software in simulation of water flow, in which the effects of turbulent are well considered. In this software, the Navier-Stokes equations are numerically solved. Volume of fluid method is applied to simulate the free surface water accurately. The results of the model in terms of pressure distribution at bed, pressure distribution in depth, velocity profile and water surface profile were compared with the results of an analytical model of streamline method as well as with the available experimental data. The analytical model is a streamline method based on conformal mapping with the basic assumption of ideal flow. The results of the model were compared in various slopes and water velocities. The study showed that numerical model can predict water surface profile and dynamic pressure properly and the results of numerical model are more accurate as compared to analytical model for the two important parameters of pressure distribution at the bed and the velocity profile. The pressure distribution was reasonably predicted by the numerical model at the bed of channel before the ramp for all the studied degrees and at the bed on the ramp for smaller degrees. The maximum error was nearly 5-10 percent. The velocity profile calculated by the numerical model was very close to the experimental data and the maximum error was nearly 5 percent. The analytical method was found quite capable in prediction of dynamic pressure and water surface profile, and less accurate in predicting the velocity profile. The study also showed that before and after the slope change, the influence length, where the dynamic pressures are significant, is dependent on the degree of sudden slope change and also on the amount of normal depth. Furthermore, the water surface profiles calculated by the numerical model and the analytical model were quite coincident, showing that the effects of gravity, viscosity and turbulence parameters on the water surface profile are insignificant.}, Keywords = {hydrodynamic pressure,Fluent,Fluent,Aeration ramp,chute,Sudden slope change,Numerical solution,Streamline method,Aerator}, volume = {12}, Number = {1}, pages = {0-0}, publisher = {Tarbiat Modares University}, title_fa = {وضعیت جریان در محل تغییر شیب ناگهانی سرریزها}, abstract_fa ={سرریزهای ریزش آزاد (شوت)، یکی از سازه‌های مهم بسیاری از سدها است. در سرریز سدهای بلند، بیشتر مواقع برای جلوگیری از پدیده کاویتاسیون با ایجاد یک رمپ و پله روی سرریز، هوادهی به جریان انجام می‌شود. ایجاد رمپ روی سرریز سبب فاصله افتادن بین جت آب و بستر شده و باعث وارد شدن هوا به جریان می‌شود. برای بررسی هوادهی، بررسی وضعیت جریان روی رمپ و به عبارتی محل تغییر ناگهانی شیب، حائز اهمیت است. در این پژوهش با استفاده از مدل عددی FLUENT، مشخصه‌های جریان در محل تغییر شیب ناگهانی سرریز، بررسی شده است. نتایج مدل عددی، مانند فشار در بستر، فشار در عمق، پروفیل سرعت و پروفیل سطح آب با نتایج حل تحلیلی جریان ایده‌ال و همچنین داده‌های آزمایشگاهی مقایسه و تجزیه و تحلیل شده است. نتایج نشان می‌دهد که مدل عددی می‌تواند به خوبی سطح آب و فشارهای دینامیکی را محاسبه کند. در مورد دو پارامتر مهم پروفیل سرعت و توزیع فشار در بستر، نتایج حل عددی نسبت به حل تحلیلی تطابق بیشتری با نتایج آزمایشگاهی دارد. با توجه به مقایسه‌های انجام‌شده می‌توان نتیجه گرفت که در تمام زوایای تغییر شیب، در قسمت کانال سرریز و نیز محل تغییر شیب، نتایج فشار در بستر در مدل عددی نسبت به نتایج تحلیلی تطابق بیشتری با نتایج آزمایشگاهی دارد. همچنین این قاعده روی رمپ سرریز به‌ویژه در زوایای کم، درست است. بیشینه‌ی خطای نتایج فشار در بستر در مدل عددی 5 تا 10 درصد است. حل عددی، پروفیل سرعت را به درستی با خطای حدود 5 درصد ارائه می‌دهد. روی کانال و رمپ به ترتیب قبل و بعد از تغییر ناگهانی، طول تأثیر شیب بر فشار بستر به زاویه تغییر شیب و عمق نرمال بالادست وابسته است. سرانجام، نتایج پروفیل سطح آب حاصل از حل عددی و تحلیلی تقریباً بر هم منطبق است که این انطباق به معنی تأثیر بسیار کم لزجت، گرانش و عامل آشفتگی بر پروفیل سطح آب است}, keywords_fa = {هواده سرریز,تغییر شیب ناگهانی,فشار دینامیکی,حل عددی,پروفیل سرعت,پروفیل سطح آب}, url = {http://mcej.modares.ac.ir/article-16-930-en.html}, eprint = {http://mcej.modares.ac.ir/article-16-930-en.pdf}, journal = {Modares Civil Engineering journal}, issn = {}, eissn = {2476-6763}, year = {2012} } @article{ author = {Omidbeigi, M. A. and Ayyoubzadeh, S. A. and SafarzadehGendeshmin, A.}, title = {Experimental and Numerical Study of Three Dimensional Flow Structure at Lateral Intake}, abstract ={The flow at a channel bifurcation is turbulent, highly three-dimensional (3D) and has many complex features. There is transverse motion accompanying the main flow and an extensive separation zone that develops in the branch channel. There are two complex flow regions along the intake channel: one is the separation zone and the other is the region in which helical motion of water particles forms. This separation occurs because the flow entering the branch channel has considerable momentum in the direction of the main channel flow. This zone causes hydraulic and sedimentation problems that must be known before designing the system. This necessitates a deeper insight into the flow patterns and shear stress distributions near the solid boundaries. In this research, 3D flow patterns at lateral diversion were investigated experimentally and numerically. The experimental investigation was carried out at a T-junction, formed by two channels with rectangular cross-sections. The width of lateral intake to the main channel was 0.4. 3D velocity measurements were obtained using Acoustic Doppler Velocimeter at junction region for 11%, 16% and 21% discharge ratios. Fluent mathematical model was then used to investigate the dividing open-channel flow characteristics. Turbulence was modeled by Two Equation (k-ε, k-ω) and Reynolds Stress (RSM) turbulence models. The predicted flow characteristics were validated using experimental data and the proper model was selected for hydrodynamic and parametric studies. Within the main channel, good agreement was obtained between all models prediction and the experimental measurements, but within the lateral channel, the RSM predictions were in better agreement with the measured data, and k-ω predictions was better than those of k-ε. The comparison of experimental and numerical streamlines at different elevations showed that the selected model is capable to simulate the most important features of flow at diversions. The study of the velocity contours at different elevations showed that the velocity magnitude decreases at main channel, just downstream corner of lateral intake at the near bed levels and this causes the sedimentation in movable beds. The results showed that the width of separation zone at lateral intake will decrease and the distance of dividing stream surface from left bank of the main channel will increase by increasing of the discharge ratio. Investigation of the flow pattern at the entrance of the lateral intake showed that the secondary flow will form at this section. The dimension of the secondary flow at near bed elevation will increase by increasing of the discharge ratio and this causes entering of more bed load into the lateral channel.}, Keywords = {secondary flow,Lateral intake,Experimental investigation,Fluent CFD model,Turbulence model}, volume = {12}, Number = {1}, pages = {0-0}, publisher = {Tarbiat Modares University}, title_fa = {مطالعه آزمایشگاهی و عددی ساختار سه بعدی جریان در آبگیری جانبی از رودخانه}, abstract_fa ={در این پژوهش، الگوی سهبعدی جریان در آبگیری جانبی از مسیر مستقیم، هم زمان به صورت آزمایشگاهی و عددی شکل، حاصل از برخورد دو کانال مستطیلی با بستر صلب و نسبت عرض کانال آبگیر به T بررسی شد. آزمایشها در یک تقاطع 16 ، برای سه نسبت دبی آبگیری 11 ADV کانال اصلی 40 درصد انجام شد. سرعتهای سه بعدی جریان در محدوده آبگیر با دستگاه و 21 درصد برداشت شد. مطالعه عددی الگوی جریان با استفاده از مدل سه بعدی فلوئنت انجام شد . برای مدل سازی آشفتگی از استفاده شد. با مقایسه نتایج به دست آمده از شبیه سازی (RSM) و همچنین مدل تنش رینولدز (k-ω و k-ε) مدلهای دو معادلهای عددی و نتایج آزمایشگاهی، مدل مناسب برای مطالعات هیدرودینامیک و پارامتریک انتخاب شد . مقایسه نتایج به دست آمده از مدلهای آشفتگی با نتایج آزمایشگاهی نشان داد که الگوی جریان داخل کانال اصلی به وسیله ی هر سه مدل به خوبی پیشبینی شده بوده است. مقایسه خطوط k-ε بیشتر از مدل k-ω نسبت به دو مدل دیگر بهتر عمل کرده و قابلیت مدل RSM اما در کانال آبگیر، مدل جریان به دست آمده از نتایج آزمایشگاهی و عددی در ترازهای مختلف نشان دهنده قابلیت مدل استفاده شده در شبیهسازی ویژگی - های جریان در آبگیرها است. مقایسه منحنیهای هم سرعت در ترازهای مختلف نشاندهنده کاهش چشم گیر سرعت جریان در لبه پایین دست دهانه آبگیر در ترازهای پایینی بوده که در بسترهای متحرک ناحیه، محتمل رسوب گذاری خواهد بود. نتایج نشان میدهد که با افزایش نسبت دبی انحرافی، عرض ناحیه جدایی جریان داخل آبگیر کاهش یافته و فاصله خط تقسیم جریان از دیواره داخلی کانال اصلی افزایش مییابد. با مقایسه جریانهای ثانویه دهانه آبگیر در نسبتهای مختلف دبی ، مشاهده شد که با افزایش نسبت دبی انحرافی، گستردگی جریانهای ثانویه در ترازهای پایینی، بیشتر شده که این امر سبب جاروب رسوبات بیشتری از مقابل دهانه آبگیر و انتقال آنها به کانال آبگیر خواهد شد.}, keywords_fa = {جریان ثانویه,آبگیری جانبی,بررسی آزمایشگاهی,مدل ریاضی فلوئنت,مدلهای آشفتگی}, url = {http://mcej.modares.ac.ir/article-16-9907-en.html}, eprint = {http://mcej.modares.ac.ir/article-16-9907-en.pdf}, journal = {Modares Civil Engineering journal}, issn = {}, eissn = {2476-6763}, year = {2012} } @article{ author = {Mohebbi, M. and Shakeri, K. and Majzoub, H.}, title = {Genetic Algorithm Based Approach for Optimal Design of Multiple Tuned Mass Dampers (MTMDs) under Earthquake Excitation}, abstract ={To improve the behavior of building structures subjected to lateral loads, such as wind and earthquake excitations, tuned mass damper (TMD) has been used extensively theoretically and experimentally in previous researches. To increase the effectiveness of TMD mechanism, different methods have been proposed to determine the optimal values of TMD parameters including its mass, stiffness and damping. In using single TMD on the structures subjected to external vibrations, the mistuning of TMD, variation of TMD damping and changes in structural dynamic characteristics cause significant reduction in the effectiveness of TMD. Multiple tuned mass dampers (MTMDs) have been proposed to overcome the shortcomings of single TMD where each TMD has different dynamic characteristics. Based on the results of different researches, it has been concluded that the performance of MTMDs is less sensitive to uncertainty of structural dynamic parameters than that of a single TMD. In the previous researches, for designing MTMDs on the linear structures subjected to various external excitations, several methods have been proposed based on different kinds of design criteria. In most of the proposed methods, to simplify the design procedure of MTMDs, some limitations such as identical masses and damping ratios for TMDs or uniform distribution for the frequency or damping of TMDs have been considered. Also these methods require extensive numerical analysis. To generalize the design problem of MTMDs, in this paper, an effective method has been proposed for optimal design of MTMDs on the multi-degree-offreedom linear structures subjected to any desired excitation. In this method, an optimization problem is defined for designing the optimal MTMDs. The minimization of the maximum displacement of structure is considered as objective function and the parameters of TMDs are considered as variables. Since the design problem includes a large number of variables, hence, in this paper, it has been decided to use Genetic Algorithm (GA) for solving the optimization problem. To illustrate the procedure of the proposed method and also to assess the effectiveness of MTMDs in improving the seismic behavior of structures, a ten–storey linear shear building frame was subjected to white noise excitation and for different values of TMDs mass ratio and TMDs number, optimal MTMDs were designed for minimizing the maximum displacement of structure. To focus on the main objective of this paper and avoid the complexity of the problem, TMDs were located on the top floor in parallel configuration. The results of numerical simulations showed the capability of GA in solving complex MTMDsdesign problem with a large number of variables as well as the simplicity of the method under any desired external excitation. Also it was concluded that increasing of the mass ratio of TMDs could improve the effectiveness of MTMDs. To assess the performance of optimal MTMDs under other earthquakes, which are different in characteristics with design record, optimal structure-MTMDs was tested under near-fault and far-fault earthquakes and the results have been reported.}, Keywords = {optimization,passive control,Tuned Mass Damper (TMD),Multiple Tuned Mass Damper (MTMD)}, volume = {12}, Number = {1}, pages = {0-0}, publisher = {Tarbiat Modares University}, title_fa = {روشی بر پایه استفاده از الگوریتم ژنتیک برای طراحی بهینه‌ی میراگر جرمی تنظیم‌شده‌ی چندگانه تحت ارتعاش زلزله}, abstract_fa ={برای بهبود کارایی و توانایی میراگر جرمی تنظیم‌شده (TMD) در سازه های خطی و غیرخطی، استفاده از میراگر جرمی چندگانه (MTMD) با مشخصات دینامیکی متفاوت برای میراگرهای جرمی، پیشنهاد شده است. در این پژوهش یک روش مؤثر برای تعیین پارامترهای بهینه‌ی MTMD در سازه های چند درجه‌آزادی خطی پیشنهاد شده که بر پایه‌ی تعریف یک مسئله بهینه‌سازی است که در آن کمینه کردن بیشینه پاسخ سازه به‌عنوان تابع هدف و پارامترهای TMD به‌عنوان متغیرهای مسئله در نظر گرفته شده است. برای حل مسئله بهینه‌سازی از الگوریتم ژنتیک (GA) استفاده شده است. برای بررسی کارایی روش پیشنهادی، یک قاب برشی 10طبقه تحت ارتعاش اغتشاش سفید قرار گرفته و برای مقادیر مختلف درصد جرمی و تعداد مختلفTMD ، سامانه میراگر جرمی چندگانه‌ی بهینه طراحی و کارکرد آن در مقابل تحریک‌های لرزه ای دورگسل و نزدیک گسل آزموده شده است. نتایج به‌دست آمده ساده و مؤثر بودن روش پیشنهاد شده را در طراحی بهینه MTMD، تحت هر ارتعاش خارجی نشان می دهد. همچنین بهبود کارایی ساز و کار MTMD با افزایش درصد جرمی آشکار است.}, keywords_fa = {کنترل غیرفعال,میراگر جرمی تنظیم‌شده,میراگر جرمی تنظیم‌شده‌ی چندگانه,بهینه‌سازی}, url = {http://mcej.modares.ac.ir/article-16-1633-en.html}, eprint = {http://mcej.modares.ac.ir/article-16-1633-en.pdf}, journal = {Modares Civil Engineering journal}, issn = {}, eissn = {2476-6763}, year = {2012} } @article{ author = {Ghasemzadeh, H and AkbariJalalabad, E.}, title = {Computing the Compressive Strength of Cement Composite Reinforced with Carbon Nanotube Assuming Isotropic Behavior for CNT}, abstract ={For extraordinary properties of carbon nanotube (CNT), a lot of research has been done about its application to reinforce different materials such as electronic and building materials, and good effects of CNT have been observed. Experimental approach for determining the properties of composites containing fibers, especially carbon nanotubes, needs using of complex experimental methods and expensive laboratorial equipments. Theoretical approach can lower the cost of predicting properties of these composites. So, in this paper, an analytical relation is presented by continuum mechanics method to predict the compressive strength of cement composite reinforced with carbon nanotube. For simplicity of computations, carbon nanotubes were assumed to be isotropicand firstly oriented unidirectionally and uniformly in the cement composite. Representative Elementary Volume(REV), as anindicatorelement of this nanocompositeis, was chosen and analyzed by continuum mechanics method. A fiber embedded in a cylinder of cement with certain radius is named REV. The strains under loads were calculated and the stresses were obtained by Hook’s law. Then, for prediction failure of composite, von Mises’ yield criterion was applied and by that, the compressive strength of cement composite reinforced with unidirectionally oriented carbon nanotubes was obtained. For real cases, the results of this analysis should be generalized to cement composites reinforced with random orientation of nanotubes, since there is no control on the distribution of fibers in the laboratory and they are oriented randomly in composites, although researchers are studying on production of CNT/cement composites with arbitrary orientation of fibers.To apply the random orientation effect, Cox’s method was used. For this purpose, the fibers' distribution function f ( ) was assumed and it was observed that the random orientation of fibers reduces the effect of fiber reinforcing with respect to unidirectional orientation. Therefore, an orientation factor  1 was used considering random orientation in comparison with unidirectional orientation. As a suggestion, this factor can be experimentally obtained too. Experimental method was used to determine the orientation factor of fibers incomposites and good results were obtained. Then the presented analytical relationship was compared with experimental data. Matches and differences between the analytical method and the experimental data were studied and the suggestions were presented to lower the differences between the analytical and experimental methods. The effect of some parameters such as compressive strength of cement and the amount of carbon nanotubes added on the compressive strength of CNT/cement composite were obtained too. Accordingly that an ideal nanocomposite with regard to economical considerations can be obtained.}, Keywords = {Cement nanocomposite,Carbon nanotube (CNT),compressive strength,Representative Elementary Volume (REV),Isotropic behavior}, volume = {12}, Number = {1}, pages = {0-0}, publisher = {Tarbiat Modares University}, title_fa = {تعیین مقاومت فشاری کامپوزیت سیمان تقویت‌شده با نانوتیوب کربن با فرض همسانگردی نانوتیوب‌ها}, abstract_fa ={نانو تیوب کربن خواص چشم‌گیری دارد و تحقیقات زیادی در مورد کاربرد آن در تقویت مواد مختلف از جمله مواد ساختمانی انجام شده و اثر مثبت نانوتیوب‏ها مشاهده شده است. استفاده از روش‏های تجربی برای تعیین خواص کامپوزیت‏های تقویت‌شده با نانوتیوب‏ کربن، نیازمند تجهیزات آزمایشگاهی گران و روش‏های پیچیده است؛ بنابراین در این پژوهش با استفاده از روش‏های تحلیلی، رابطه‏ای برای تعیین مقاومت فشاری کامپوزیت سیمان تقویت‌شده با نانوتیوب کربن به‌دست می‏آید. برای سادگی محاسبات، فرض شده ‏است که نانوتیوب‏ها ایزوتروپ بوده و در ابتدا داخل کامپوزیت ‏به صورت تک‌جهته و همگن چیده شده است. حجم پایه معرف به عنوان المان نماینده از این نانوکامپوزیت انتخاب شده و به روش مکانیک محیط پیوسته، تحلیل می‌شود. با این تحلیل، مقاومت فشاری کامپوزیت سیمان تقویت‌شده با چیدمان منظم الیاف محاسبه می‏شود. در موارد عملی، نتایج این تحلیل برای یک کامپوزیت سیمانی دارای چیدمان تصادفی نانوتیوب کربن تعمیم داده شده و رابطه تحلیلی به‌دست‌آمده با نتایج آزمایشگاهی مقایسه شده است.}, keywords_fa = {مقاومت فشاری,نانوکامپوزیت سیمان,نانوتیوب کربن,حجم پایه معرف,توزیع تصادفی الیاف}, url = {http://mcej.modares.ac.ir/article-16-11008-en.html}, eprint = {http://mcej.modares.ac.ir/article-16-11008-en.pdf}, journal = {Modares Civil Engineering journal}, issn = {}, eissn = {2476-6763}, year = {2012} } @article{ author = {Azarhoosh, Z. and GhodratiAmiri, G. R. and Razeghi, H.R.}, title = {Response of Soil-Structure Systems Subjected to Forward Rupture Directivity Pulses}, abstract ={The combined effects of two major contributing factors, i.e. inertial soil-structure interaction (SSI) and near-fault ground motions, on structural responses were studied. Considering nearfault characteristics, soil-structure systems are subjected to both actual near-fault ground motion records and their dominant kinematic characteristics, i.e. forward rupture-directivity pulses, coherently travelling waves seen as a large amplitude and short duration pulse-type motion at the beginning of each fault-normal component of the record. As a result of the suitability of forward rupture-directivity pulses for quantifying the salient response features of structures, a mathematical model, proposed by Makris, was used to represent the forward rupture-directivity pulse-type motions. Using a comprehensive parametric study, the structure, a bilinear single degree of freedom (SDOF) system, the soil beneath the structure and a homogeneous elastic half-space were combined based on a discrete model to constitute the overall soil-structure model. The results have been presented in the form of elastic strength demand graphs for a wide range of non-dimensional key parameters, which describe the SSI effects. Both the soil-structure systems and the corresponding fixed-base structures were considered and compared. Using numerical time-stepping analyses, it was found that the response of soil-structure systems subjected to actual near-fault records is similar to those subjected to forward rupture-directivity pulses. Consequently, the forward rupture-directivity pulses can be used to predict the salient response features of soil-structure systems in seismically active regions. They can also be a realistic representation of near-fault ground motions for predicting the response of long-period structures. It was further observed that quite interestingly, the response of soil-structure systems subjected to actual near-fault records, has two maximum regions. However, it was recognized that further study would be required to clarify these regions. The results also indicated that considering SSI is critical for a variety of structures. Accordingly, underestimated near-fault responses could be obtained when the SSI effects are ignored.}, Keywords = {Soil-Structure Interaction,Near-Fault ground motions,Forward rupturedirectivity pulses,Elastic Response of Structures}, volume = {12}, Number = {1}, pages = {0-0}, publisher = {Tarbiat Modares University}, title_fa = {پاسخ سیستم‌های خاک- سازه به پالس‌های ناشی از جهت‌گیری پیشرونده‌ی انتشار شکست در نواحی نزدیک گسل}, abstract_fa ={در این مطالعه آثار ترکیبی اندرکنش خاک-سازه و زلزله‌های نزدیک گسل بر پاسخ ارتجاعی سازه‌های یک درجه‌آزادی سیستم خاک-سازه تحت اثر پالس‌های ناشی از جهت‌گیری پیش‌رونده انتشار شکست به عنوان نماینده‌ی خصوصیات سینماتیکی زلزله‌های حوزه‌ی نزدیک گسل، بررسی شده است. نحوه‌ی تغییرات مقاومت تقاضای ارتجاعی سازه بر حسب محدوده‌ی وسیعی از پارامترهای بی‌بعد که معرف آثار اندرکنش خاک- سازه و نزدیک گسل است، ارائه می‌شود. برای ارزیابی آثار خاک بر پاسخ ارتجاعی سازه‌ها در اثر زلزله‌های نزدیک گسل، پاسخ سازه‌ی مستقر بر بستر صلب نیز براورد شده و با نتایج سازه‌ی مستقر بر بستر خاک مقایسه می‌شود.}, keywords_fa = {اندرکنش خاک-سازه,زلزله‌های نزدیک گسل,پالس‌های جهت‌گیری پیش‌رونده انتشار شکست,پاسخ ارتجاعی سازه‌ها}, url = {http://mcej.modares.ac.ir/article-16-8964-en.html}, eprint = {http://mcej.modares.ac.ir/article-16-8964-en.pdf}, journal = {Modares Civil Engineering journal}, issn = {}, eissn = {2476-6763}, year = {2012} } @article{ author = {Khatami, S.M. and Kheyroddin, A.}, title = {Investigation of Element Size Effect on the Nonlinear Behavior of Flanged Shear Walls}, abstract ={Completion and development of reliable analytical models using finite element method could help investigation and prediction of the actual structure response results. Analysis of each model in finite element software needs meshing, in which computer results are dependent specifically to geometry and dimensions of the elements, called "mesh dependence". Finding a strategy for independency of the results to meshing is tangible. For the mentioned purpose and also to investigate the role of finite elements meshing in flanged shear walls, finite element software was used. Different meshings of shear walls (tested by Vecchio and Palermo) were analyzed and studied. The results of analyses with different meshs showed different ultimate strengthes and lateral displacementes. Different shapes of mesh create various results, which are indicated in the finite element model. By increasing of the size of mesh, the final force was increased and the lateral displacement was decreased, which presents a rigid model. On the other hand, by decreasing of the dimension of mesh, a stiff model was seen. So, it is a need to create well proses to analyze and evaluate the flanged section of shear walls with finite element model. Getting suitable accuracy of finite element model, the mentioned concrete shear wall (vecchio and Palermo) was modeled by ANSYS. 3D SOLID65 element was employed for modeling of shear wall structures. This element is capable of cracking in tension and crushing in compression. In concrete applications, for instance, the solid capability of the element may be used to model the concrete while the rebar capability is available for modeling of reinforcement behavior. After calibration, optimum forms and dimensions are recommended. As an illustration, an idea was presented, by which flanged shear wall could be analyzed more carefully in ultimate strength and ductility. This analysis showed that the results of squared mesh are closer to the fact. For example, this type of meshing 6% error in ultimate strength and ductility in accordance to lab Specimen, presented the closer responses. Furthermore, investigation on the optimum size of the mesh showed that if the mesh has the same size of the thickness of the connecting element (Shear Wall Web), the results will have very high accuracy. For instance, squared meshes with same dimension of meshes equal to web thickness, rather than those with half dimension of that led to 1% of lateral resistance, which is closer to experimental test. It is possible that web thickness is 150 mm, thereby, we can use mesh sizes of 150mm, 75mm or 50mm. However, in order to obtain ultimate loads accurately, the mesh size of 150mm seems reasonable. Square meshes have four degrees of freedom. If the size of square is chosen to be the same as the web thickness, nodal forces induced in the web would be proportionate. For thischallenge, a flanged section reinforced concrete shear wall tested was selected to confirm the web thickness square theory. This shear wall was modeled by finite element program. The results of analysis showed accuracy in the investigated theory. In this study, the web thikness square theory has indicated 8% error in ultimate strength.}, Keywords = {Finite Element,Flanged shear wall,Element Size,Web Thickness Square,Mesh dependency}, volume = {12}, Number = {1}, pages = {0-0}, publisher = {Tarbiat Modares University}, title_fa = {تأثیر اندازه المان بر رفتار غیرخطی دیوارهای برشی بالدار}, abstract_fa ={تکمیل و توسعه مدل‌های تحلیلی قابل اطمینان با روش المان محدود می‌تواند کمک بسیار زیادی به بررسی و پیش‌بینی نتایج سازه‌ها کند. تحلیل هر مدل در نرم‌افزار المان محدود، نیاز به المان‌بندی دارد که نتایج کامپیوتری به‌صورت مشخص به هندسه و ابعاد آن المان وابسته است. که این پدیده را وابستگی مش می‌گویند. نیاز به یافتن روشی بدون وابستگی نتایج به المان‌بندی محسوس است؛ بنابر این و برای بررسی نقش‌مش بندی المان‌های محدود در دیوارهای برشی بالدار با استفاده از یک نرم‌افزار المان محدود، شبکه‌بندی‌های مختلف یک دیوار برشی بالدار آزمایش‌شده، تحلیل و بررسی شده و پس از کالیبره کردن مدل، شکل‌ها و ابعاد بهینه آن پیشنهاد می‌شود. برای المان‌بندی‌ها، ایده جدیدی ارائه شده که با استفاده از آن می‌توان تحلیل دیوارهای برشی بالدار را با دقت بیشتری برای تطبیق مقاومت نهایی و شکل‌پذیری انجام داد.}, keywords_fa = {المان محدود,دیواربرشی بالدار,اندازه المان,مربع ضخامت جان,وابستگی مش}, url = {http://mcej.modares.ac.ir/article-16-2676-en.html}, eprint = {http://mcej.modares.ac.ir/article-16-2676-en.pdf}, journal = {Modares Civil Engineering journal}, issn = {}, eissn = {2476-6763}, year = {2012} } @article{ author = {Nasiri, A. and Mokhtarani, N. and Ganjidoust, H.}, title = {Post Treatment of Composting Leachate by Means of Ozonation and Granular Activated Carbon (GAC) Adsorption}, abstract ={There are different methods for treatment of composting leachate. Parameters dictating which method to be chosen include quantity and quality of the leachate, required amount of treatment and economical issues. Integration of ozonation and GAC adsorption into a single process is one of the attractive methods for post treatment of wastewater. Therefore, post treatment of composting leachate by means of ozonation and granular activated carbon (GAC) adsorption was considered as the main objective of this study. This study was conducted in laboratory scale and in batch mode. The set-up of batch system consisted of a Plexiglas column with 20 mm inner diameter and 800 mm height. The tall height of the column provides the required contact time between ozone and pollutants. Ozone was supplied to the column through a diffuser sited at its bottom. The outlet gas of the reactor may contain some residual ozone and can cause air pollution. Therefore, it is dangerous for the people working nearby the reactor. Thus, the ozone in the gas phase leaving the column was removed by KI solution. All experiments were conducted at room temperature (24 ±2°C). The leachate used in this study was obtained from the effluent of the Leachate Treatment Plant of Rasht Composting Facility (Guilan, Iran). All the chemicals employed for analysis were analytical grade and obtained from the reliable companies. In order to conduct the experiments, after complete determination of the specifications of GAC as an adsorbent, different dosages of GAC were added to 800 mL of leachate with the given initial concentration and pH in the column. The pH value of the solution was adjusted by Sulfuric Acid or Sodium Hydroxide as needed. Then the ozone gas was introduced into the column and the samples were taken in different intervals of time. After that required parameters of the samples were measured. Ozone generator (ARDA-COG 5S) with 5 gr/hr nominal capacity was used to produce ozone gas from pure and dry oxygen. Before starting each step of the experiment, the ozone generator was calibrated for ozone concentration. Pressure and flow rate of ozone gas produced was equal to 2 bara and 1 liter per minute, respectively. The results showed that integrated treatment of the leachate with ozonation and activated carbon adsorption, namely catalytic ozonation, was more effective than each process solely. In this study, COD removal rate of 44% in adsorption process, 57% in ozonation process and 80% in integrated process was achieved after 60 minutes. According to the results, in the integrated process, addition of the adsorbent (as long as it floats in the leachate) has positiveeffect on the removal of organic load. The pH value is another important parameter that affects the removal rate in the integrated process. It was found that removal of organic load is more evident at basic condition than at acidic condition. In this study, the maximum COD removal was achieved in the pH values between 8 and 9. Furthermore, in this process, ozonation along with adsorption process resulted in reactivation of activated carbon and avoided frequent GAC regeneration. After 5 times of the reuse of virgin GAC through a consecutive experiment, only 7% loss in COD removal was observed in the integrated process, while it reached to 95% for single adsorption process at the same condition. This can be explained either by the predominance of catalytic reactions rather than adsorptionoxidation reaction in the process or to the in situ regeneration of GAC.}, Keywords = {leachate,Ozonation,Granular activated carbon,Adsorption,compost}, volume = {12}, Number = {1}, pages = {0-0}, publisher = {Tarbiat Modares University}, title_fa = {تصفیه تکمیلی شیرابه به‌وسیله‌ی ترکیب ازن‌زنی و جذب سطحی}, abstract_fa ={در این پژوهش، تصفیه تکمیلی شیرابه به دست آمده از فرایند کمپوست زباله شهری از طریق فرایند ترکیبی جذب و ازن‌زنی بررسی شد. بر اساس نتایج به دست آمده، فرایند ترکیبی در مقایسه با فرایند جذب و ازن‌زنی، توانایی بیشتری برای حذف آلاینده دارد؛ به‌گونه‌ای که پس از 60 دقیقه، نرخ حذف COD از 44 درصد در فرایند جذب و 57 درصد در فرایند ازن‌زنی به بیش از 80 درصد در فرایند ترکیبی رسید. بر اساس آزمایش‌های انجام‌شده در فرایند ترکیبی افزودن کربن فعال تا هنگامی که در سیال به صورت شناور باقی بماند؛ بر حذف بار آلی از شیرابه تأثیر مثبت خواهد داشت. pH نیز یکی دیگر از پارامترهای مؤثر بر نرخ حذف، در فرایند ترکیبی است. بر اساس نتایج به دست‌آمده، در شرایط انجام این پژوهش، بیشینه‌ی حذف بار آلی در pH 8 تا 9 به دست آمد. در این فرایند، ازن‌زنی به صورت هم‌زمان باعث احیاء کربن فعال درداخل رآکتور نیز شده، که افزایش زمان اشباع بستر کربنی و کاهش هزینه‌های احیاء آن خارج از رآکتور را منجر خواهد شد. در این پژوهش پس از 5 مرحله استفاده پی‌ در پی از بستر کربنی، نرخ حذف بار آلی در فرایند ترکیبی تنها حدود 7 درصد و در فرایند جذب به خاطر اشباع شدن جاذب، بیش از 95 درصد کاهش یافت. این موضوع بیانگر احیاء هم‌زمان کربن فعال در رآکتور و یا غالب بودن ساز و کار اکسیداسیون کاتالیستی بر ساز و کار جذب- اکسیداسیون است.}, keywords_fa = {شیرابه,ازن‌زنی,کربن فعال دانه‌ای,جذب,کمپوست}, url = {http://mcej.modares.ac.ir/article-16-2317-en.html}, eprint = {http://mcej.modares.ac.ir/article-16-2317-en.pdf}, journal = {Modares Civil Engineering journal}, issn = {}, eissn = {2476-6763}, year = {2012} } @article{ author = {Jalali, A.R. and Yasrebinia, Y.}, title = {Investigation of Steel Welded Moment Connections Performance under Column Collapse}, abstract ={Progressive collapse of buildings has raised questions on adequacy of the existing regulations to prevent local and, in turn, global collapses. The present study mostly focuses on the performance of welded moment connections against progressive collapse. The performance of moment connections suggested in the FEMA 350, which are proper for seismic forces, Welded Flange Plate (WFP), Reduced Beam Seaction (RBS), Welded Unreinforced Flange- Welded Web (WUF-W) and Free Flange (FF), has been studied. The models used include non-linear behavior of materials and geometrical nonlinear behavior. The behavior of steel materials used in the structure is the true behavior of steel was stress-strain, which has been considered in the model completely. The nonlinear stress-strain behavior of steel selected for modeling the real behavior of beam and column members in the structure. The material properties of all steel components were modeled using elastic-plastic material model from ABAQUS. For connection region porous material plasticity was used. The diagram of vertical force against vertical displacement for each connection was drawn, and the state of each connection failure was investigated. Making the large scale experimental models to study the progressive collapse of structures seems too difficult. Using finite element models to study the behavior of structures are relatively appropriate option with regard to time and cost. In all of the numerical models, shell (S4) element has been used to simulate the beams, columns and connections. This is a four-node element, which contains four integration points on the element. During the calculations, full integration method with more precision was used. For analysis of the models, dynamic explicit method was used. This method is suitable to analyze the models with more members having nonlinear characteristics of materials and large deformations. In this method, the central difference integrating is used to solve the dynamic equations. In every time step, this method performs simpler than other methods in solving dynamic equations since there is no need to inverse stiffness matrix in any time stage. The used numerical method has compared using the laboratorial results, which have tested in 2010 by NIST. The analytical results showed a good agreement with laboratory models. The results of numerical analyses illustrated that RBS connection has less strength in comparison with other connections and this connection reaches maximum vertical displacement with less force. Performance of FF and WUF-W connections is similar to each other. These connections more resistant in comparison with RBS. WFP connection is more resistant as compared with the WUF-W, FF and RBS connections against the failure of the column. Failure load in WFPconnection is twice of other connection, and according to the analytical results, this connection is suitable for HLOP structures. In all connections, rotation capacity corresponding to collapse prevention against column removal scenario is about twice of the accepted criteria that FEMA 350 has suggested for seismic loads.}, Keywords = {Moment frame,Explicit Dynamic Analysis,Ductile fracture,large deformation,Material Nonlinearity}, volume = {12}, Number = {1}, pages = {0-0}, publisher = {Tarbiat Modares University}, title_fa = {بررسی تغییر کارکرد اتصالات جوشی خمشی فولادی در اثرخرابی ستون}, abstract_fa ={این پژوهش به‌طور عمده بر روی کارکرد اتصالات جوشی خمشی در سازه‌های فولادی در برابر خرابی ستون می‌پردازد. کارکرد چهار اتصال خمشی پیشنهادشده در آیین‌نامهFEMA 350 که برای نیروهای لرزه‌ای مناسب است WFP و RBS و WUF-W و FF در برابر خرابی ستون بررسی شده است. دیاگرام نیرو تغییر مکان برای هر اتصال رسم شده و حالت‌های خرابی هر اتصال نشان داده شده است. تحلیل عددی استفاده شده، ابتدا با نتایج آزمایشگاهی که در سال 2010 به‌وسیله‌ی موسسه NIST انجام شده مقایسه شده است. نتایج نشان می‌دهد که فرضیات استفاده‌شده در مدل عددی، مطابقت خوبی با مدل آزمایشگاهی دارد. نتایج به‌دست‌آمده از تحلیل عددی نشان داد که اتصال RBS مقاومت کمتری نسبت به سایر اتصالات دارد و با نیروی کمتری به تغییر مکان بیشینه می‌رسد. اتصال FF و اتصال WUF-W از نظر کارکرد شبیه هم بوده و مقاومت بیشتری نسبت به اتصال RBS دارند. اتصال WFP نسبت به اتصالات FF, WUF-W و RBS در برابر خرابی ستون مقاومت بیشتری دارد؛ به‌گونه‌ای‌که ظرفیت باربری این اتصال در اثر خرابی ستون، دو برابر سایر اتصالات بوده و بر اساس نتایج به‌دست‌آمده، این اتصال قابل استفاده در سازه‌های با سطح محافظت بالا در برابر خرابی پیش‌رونده است. در همه‌ی اتصالات بررسی شده، مقدار چرخش بیشتر مانند خرابی دو برابر مقداری بود که آیین‌نامه FEMA 350 به عنوان بیشینه ظرفیت چرخشی برای اتصالات بیان کرده است.}, keywords_fa = {قاب خمشی,روش تحلیل دینامیکی صریح,رفتار شکست نرم,تغییر شکل های بزرگ,غیرخطی مصالح}, url = {http://mcej.modares.ac.ir/article-16-1961-en.html}, eprint = {http://mcej.modares.ac.ir/article-16-1961-en.pdf}, journal = {Modares Civil Engineering journal}, issn = {}, eissn = {2476-6763}, year = {2012} } @article{ author = {Garivani, S. and Aghakouchek, A. A. and SoltaniMohammadi, M.}, title = {Effects of Masonry Infills on Seismic Behavior of Steel Frames with Khoreeni Connections and Their Elements}, abstract ={Steel frames with Khorjeeni connections have been widely used in the traditional construction of buildings in Iran during the past decades. In the traditional form of Khorjeeni connections, double section beams are not cut at the intersection with columns, rather they are connected to the column by means of two angles places over the top and bottom of the beam flanges. This type of connection offers advantages for frames, wich carry gravity loads, but it has deficiencies when the frames are subjected to lateral loads. Like other structural frames, there are masonry infills in many frames with Khorjeeni connections. The behavior of composite frames subject to lateral loads differs from that of bare steel frames. In this paper, positive and negative effects of masonry infills were studied on the behavior of steel frames with Khorjeeni connections. Finite element method was used to carry out nonlinear static analysis of subassemblages of this type of frames. Initially, the results of some experiments were utilized to verify the details of the model. Then numerical models of toe span or four span frames with different configuration of bracings and masonry infills were studied. The results showed that infill frames increase the stiffness and strength of frames in the absence of bracing considerably. Even when bracings are present, the increase in stiffness and strength is significant. Simplified compressive strut models proposed in recent guidelines for seismic rehabilitation of existing buildings are also utilized to analyze the models. The results show agreement with the results of more sophisticated FE models. The masonry infills, however, have some negative effects on the behavior of Khorjeeni frames. Parts of the column in the vicinity of connections are prone to plastic damage, particularly when the infills are relatively strong. The Khorjeeni connections are subjected to vertical forces and tortional moments. Due to limited vertical strength of these connections, top stories of this type of frames may suffer when compressive action of strut is mobilized for other bays. This action introduces additional moments, which may damage the connections. Therefore, considering of these negative effects of infills is very important when seismic behavior of the existing frames is assessed, because these effects limit the interstorey drift ratios.}, Keywords = {Masonry infill,Khourjeeni connection,Stiffness and ultimate strength of composite frames}, volume = {12}, Number = {1}, pages = {0-0}, publisher = {Tarbiat Modares University}, title_fa = {اثر میانقاب‌های مصالح بنایی بر رفتار لرزه‌ای قاب‌های فولادی دارای اتصالات خورجینی و اجزای آن}, abstract_fa ={در این مقاله آثارمثبت و منفی میانقاب های مصالح بنایی بر رفتار لرزه ای قاب های فولادی دارای اتصالات خورجینی بررسی شده و نتایج به‌ دست‌آمده از مدل‌سازی ها، با نتایج به دست‌امده از روش ارائه‌شده در آیین نامه بهسازی ایران در مورد میانقاب ها مقایسه شده است. مدل‌سازی های عددی در این پژوهش با نرم‌افزار اجزاء محدود ABAQUS انجام شده است. ابتدا با مقایسه نتایج مدل‌سازی عددی با نتایج آزمایشگاهی، درستی روش انتخاب‌شده برای مدل‌سازی میانقاب مصالح بنایی کنترل شده و سپس قاب های دو‌دهانه و چهاردهانه فولادی دارای اتصالات خورجینی، مهاربند ضربدری و میانقاب مصالح بنایی در نرم‌افزار، مدل شده و تأثیر میانقاب بر سختی و مقاومت نهایی قاب بررسی شده است. آثار منفی میانقاب بر اعضای کنار آن (تیر، ستون و اتصال) نیز بررسی شده است. نتایج به‌ دست‌آمده گویای آثار مثبت میانقاب ها بر سختی و مقاومت نهایی قاب مرکب و آثار منفی این اعضا بر اعضای کنار خود (تیر، ستون و به‌ویژه اتصال خورجینی) است که لزوم در نظر گرفتن این آثار منفی و تقویت اعضای کناری را قبل از در نظر گرفتن آثار مثبت میانقاب ها گوشزد می‌کند}, keywords_fa = {میانقاب مصالح بنایی,اتصال خورجینی,سختی و مقاومت نهایی قاب مرکب}, url = {http://mcej.modares.ac.ir/article-16-1632-en.html}, eprint = {http://mcej.modares.ac.ir/article-16-1632-en.pdf}, journal = {Modares Civil Engineering journal}, issn = {}, eissn = {2476-6763}, year = {2012} } @article{ author = {Sabbagh-Yazdi, S.R. and Rezaei-Manizani, H.}, title = {Using Depth Average Flow Solver of NASIR Finite Volume Software for Modeling Air Entrainment from Water Surface in Chute Flow}, abstract ={In this paper, the results of water flow modeling and computation of air distribution in chute spillways are described. The depth average flow solver of NASIR finite volume software was utilized for modeling of water flow in chute spillways. In this module, the shallow water equations modified for steep slopes are solved using cell-centre and cell-vertex schemes of finite volume method that suits unstructured triangular meshes. Using the computed velocity components and flow depth at each nodal point, the air entertainment parameters (air inception point, mean air concentration and vertical distribution of air concentration) are calculated by utilizing some empirical relations. The empirical relations for the air concentration were adopted by the pervious researchers using the measurements on large scale flow in chute spillways. In the present work, three modeling strategies were performed: 1) Solution of flow field and then calculation of air concentration parameter (as a post-processing operation after convergence of the water flow solution), 2) Coupled solution of the flow equations and air concentration relations considering the flow bulking and reduction of global friction parameters due to air entrainment and 3) Adding the air entrainment on density variation effects to the coupled solution of the flow equations and air concentration relations considering the flow bulking and reduction of global friction parameters due to air entrainment. In order to assess the quality of the results of the three modeling strategies, the readily available flow velocity and air concentration measurements on AVIMORE chute spillway were used for comparison considering the best experimental relations for simulating the entrainment of air into the flow on chute spillways. In order to provide better understanding of the velocity and air concentration, the vertical distribution profiles of these parameters were plotted from the multi-layer treatments of depth averaged computed results. Comparison of the computed velocity fields and air concentrations with the reported field measurements at the stations 503 and 505 of AVIEMORE chute spillway presents promising agreements. However, the accuracy of the 2nd and 3rd modeling strategies (in which the coupled solutions of water flow equations and air concentration relations are considered and the effect of air content on the reduction of global friction of the water flow is taken into consideration) was much better than that of the 1st modeling strategy (in which the air concentration relations are considered as post processing on water flow equation solution for depth and velocity fields). Furthermore, no significant differences were observed between the results of the 2nd and 3rd modeling strategies. Hence, it can be concluded that the effect of air concentration on density variation of the supercritical water flow does not play an important role on the results of the coupled solutions of water flow equations and air concentration relations.}, Keywords = {Modeling chute spillway flow,Vertical distribution of air entrainment from water surface,SWE for steep slope}, volume = {12}, Number = {1}, pages = {0-0}, publisher = {Tarbiat Modares University}, title_fa = {مدل‌سازی توزیع هوای واردشده از سطح جریان در تنداب با استفاده از تحلیلگر میانگین عمقی نرم‌افزار حجم محدود NASIR1}, abstract_fa ={- در این مقاله، نتایج مدل‌سازی جریان و توزیع غلظت هوای وارد‌شده از سطح جریان در تنداب سرریز، تشریح شده است. در تحلیلگر میانگین عمقی نرم‌افزار NASIR که از آن استفاده شده است، معادلات آب‌های کم‌عمق اصلاح‌شده برای شیب تند با روش حجم محدود (رئوس سلول هم‌پوشان و مرکزیت سلول) روی شبکه مثلثی بی‌ساختار حل می‌شوند. با به‌کارگیری پارامترهای عمق و سرعت میانگین عمقی جریان تحلیل‌شده به وسیله‌ی نرم‌افزار، پارامترهای هواگیری از سطح (مانند تعیین موقعیت نقطه شروع هواگیری، محاسبه غلظت میانگین هوا و توزیع عمقی آن) از روابط تجربی ارائه‌شده به وسیله‌ی محققین قبلی، گرفته شده است. در این پژوهش برای بررسی عددی پدیده هواگیری از سطح جریان در تنداب از سه شیوه استفاده شده است: 1) بدون در نظر گرفتن تأثیر ورود هوا، پارامترهای جریان، تحلیل عددی شده، سپس با استفاده از نتایج تحلیل و یک پس پردازنده، توزیع هوای وارد‌شده از سطح محاسبه می‌شود؛ 2) حل همگام جریان آب و توزیع هوا بدون اعمال تأثیر چگالی مخلوط آب و هوا در مقدار حرکت جریان با در نظر گرفتن تأثیر ورود هوا بر کاهش تنش‌های استهلاکی و تورم عمق جریان، در هر گام محاسباتی، انجام می‌شود، 3) حل هم‌زمان غلظت هوا و جریان آب با اعمال چگالی مخلوط آب و هوا در مقدار حرکت جریان انجام می‌شود و علاوه بر تأثیر ورود هوا بر کاهش تنش‌های استهلاکی و تورم عمق جریان در هر گام محاسباتی، تأثیر تغییر چگالی مخلوط آب و هوا بر تغییرات استهلاک مقدار حرکت نیز در نظر گرفته می شود. برای ارزیابی کیفیت نتایج به دست‌آمده از سه شیوه مدل‌سازی، نتایج محاسباتی جریان و غلظت هوا در تنداب سرریز سد آویمور با اندازه‌گیری‌های میدانی گزارش‌شده در مراجع، مقایسه شده است.}, keywords_fa = {مدل سازی عددی جریان در تنداب ها,توزیع عمقی ورود هوا از سطح آب,معادلات آب های کم عمق در شیب تند}, url = {http://mcej.modares.ac.ir/article-16-163-en.html}, eprint = {http://mcej.modares.ac.ir/article-16-163-en.pdf}, journal = {Modares Civil Engineering journal}, issn = {}, eissn = {2476-6763}, year = {2012} } @article{ author = {Garivani, Sadegh and Aghakouchek, Ali and SoltaniMohammadi, Masou}, title = {Effects of strengthening the masonry infills by reinforced shotcrete on seismic behavior of steel frames with Khoureeni connections and their elements}, abstract ={A large number of buildings in Iran are constructed with masonry infills for functional and architectural reasons. Often, engineers do not consider masonry infill walls in the design process because the final distribution of these elements may be unknown to them, or because masonry walls are regarded as non-structural elements. However, infill walls tend to interact with the frame when the structure is subjected to lateral loads. Masonry infills contribute to the stiffness of the infilled frame under the action of lateral load. This leads to structural response deviating from what is expected in the design. The effects of the infills on the seismic behavior of buildings may be positive or negative, depending on a large number of parameters. Steel frames with Khorjeeni connections have been widely used in the traditional construction of buildings in Iran during the past decades. In the traditional form of Khorjeeni connections, double section beams are not cut at the intersection with columns, rather they are connected to the column by means of two angles places over the top and bottom of the beam flanges. This type of connection offers advantages for frames, wich carry gravity loads, but it has deficiencies when the frames are subjected to lateral loads. Like other structural frames, there are masonry infills in many frames with Khorjeeni connections. The behavior of composite frames subject to lateral loads differs from that of bare steel frames. In this paper, positive and negative effects of masonry infills were studied on the behavior of steel frames with Khorjeeni connections. Finite element method was used to carry out nonlinear static analysis of subassemblages of this type of frames. Initially, the results of some experiments were utilized to verify the details of the model. Then numerical models of toe span or four span frames with different configuration of bracings and masonry infills were studied. The results showed that infill frames increase the stiffness and strength of frames in the absence of bracing considerably. Even when bracings are present, the increase in stiffness and strength is significant. Simplified compressive strut models proposed in recent guidelines for seismic rehabilitation of existing buildings are also utilized to analyze the models. The results show agreement with the results of more sophisticated FE models. The masonry infills, however, have some negative effects on the behavior of Khorjeeni frames. Parts of the column in the vicinity of connections are prone to plastic damage, particularly when the infills are relatively strong. The Khorjeeni connections are subjected to vertical forces and tortional moments. Due to limited vertical strength of these connections, top stories of this type of frames may suffer when compressive action of strut is mobilized for other bays. This action introduces additional moments, which may damage the connections. Therefore, considering of these negative effects of infills is very important when seismic behavior of the existing frames is assessed, because these effects limit the interstorey drift ratios.}, Keywords = {Khourjini connection,Masonary infill,Reinforced shotcrete,Stiffness and ultimate strength of infilled frame}, volume = {12}, Number = {1}, pages = {1-10}, publisher = {Tarbiat Modares University}, title_fa = {اثرات تقویت میانقاب های مصالح بنایی با استفاده از لایه شاتکریت و شبکه فولادی بر رفتار لرزه ای قاب های فولادی دارای اتصالات خورجینی و اجزای آن- دوره 12 شماره 1}, abstract_fa ={این مقاله به بررسی اثرات تقویت میانقاب¬های مصالح بنایی با استفاده از لایه شاتکریت و شبکه فولادی بر رفتار لرزه¬ای قاب¬های مرکب فولادی دارای اتصالات خورجینی می¬پردازد. برای این منظور مدل¬سازی¬های عددی در نرم افزار اجزاء محدود ABAQUS صورت پذیرفته است. ابتدا با مقایسه نتایج حاصل از مدل¬ عددی با نتایج آزمایشگاهی، درستی روش¬های انتخاب شده برای مدل-سازی میانقاب مصالح بنایی و لایه شاتکریت و شبکه فولادی کنترل گردیده و سپس قاب¬های دو دهانه و چهار دهانه فولادی دارای اتصالات خورجینی، مهاربند ضربدری و میانقاب مصالح بنایی در نرم افزار مدل شده و تأثیر تقویت میانقاب بر سختی و مقاومت نهایی قاب، مورد بررسی قرار گرفته است. همچنین اثرات منفی این تقویت¬ها بر روی اعضای مجاور آن (تیر، ستون و اتصال) نیز مشخص شده است. نتایج کلی بدست آمده، حاکی از اثرات مثبت میانقاب¬های تقویت شده بر روی سختی و مقاومت نهایی قاب مرکب و اثرات منفی این اعضاء بر روی اعضای مجاور خود (تیر، ستون و به ویژه اتصال خورجینی) می¬باشد که لزوم در نظر گرفتن این اثرات منفی و تقویت اعضای مجاور را قبل از در نظر گرفتن اثرات مثبت میانقاب¬ها گوشزد می¬نماید.}, keywords_fa = {اتصال خورجینی,میانقاب مصالح بنایی,لایه شاتکریت و شبکه فولادی,سختی و مقاومت نهایی قاب مرکب}, url = {http://mcej.modares.ac.ir/article-16-10517-en.html}, eprint = {}, journal = {Modares Civil Engineering journal}, issn = {}, eissn = {2476-6763}, year = {2012} }