فریبرز ناطقی الهی
پژوهشگاه بین‌المللی زلزله‌شناسی و مهندسی زلزله
[ 1 ] - رفتار گسیختگی و برآورد ظرفیت برشی شاه‌تیرهای مرکب بتنی-فولادی با سخت‌کننده قطری
در این مطالعه، یک روش تحلیلی جدید برای تخمین ظرفیت برشی در شاه‌تیرهای مرکب بتنیٓـ فولادی که سخت‌کننده‌ی قطری دارند، ارائه شده است. این روش بر مبنای عملکرد میدان کششی در جان شاه‌تیر فولادی و سازوکار خرابی تاوه‌ی بتنی رابطه‌سازی شده است. دقت روش پیشنهادی با استفاده از تحلیل‌های اجزاء محدود شاه‌تیرهای مرکب، که چیدمان‌های مختلفی از سخت‌کننده‌های قطری دارند، سنجیده شده است. در الگوسازی‌های اجزاء محدو...
[ 2 ] - رفتار بهبود یافته آزمایشگاهی و تحلیلی میراگر فلزی آکاردئونی تحت تأثیر افزایش لایه‌ها
در این مطالعه با هدف بهبود رفتار میراگر فلزی آکاردئونی به‌عنوان یکی از بارزترین میراگرهای فلزی جاری‌شونده در داخل کشور، تأثیرافزایش تعداد لایه‌های جداره‌ی این میراگر مورد مطالعه‌ی تحلیلی، آزمایشگاهی و پارامتریک قرار گرفته است. مطالعات آزمایشگاهی بر روی نمونه‌های تک لایه و دو لایه انجام شده و مدل‌های تحلیلی تک لایه، دو لایه و سه لایه‌ی میراگر توسعه یافته و با استفاده از نتایج مطالعات آزمایشگاهی ...
[ 3 ] - معرفی اتصال خمشی تیر به ستون قوطی فولادی بااستفاده از صفحات کناری
استفاده از تیرهای I شکل و ستون‌های قوطی در سازه‌های فولادی ایران در ساختمان‌های بلند بسیار متداول است. نقطه ضعف اساسی این سازه‌ها اتصالات آنهاست. برای اصلاح این اتصالات استفاده از اتصال با صفحه‌ی کناری توصیه می‌شود. برای دسترسی به رفتار این نوع اتصال از تحلیل استاتیکی غیرخطی و با استفاده از برنامه‌ی ANSYS رفتار هیسترزیس این اتصال با توجه به تغییر ابعاد تیر و ستون و تغییر ضخامت ورق کناری تحل...
[ 4 ] - مدل سازی و بررسی رفتار قابهای بتنی میان پر تقویت شده با کامپوزیت های پلیمری مسلح الیافی (FRP)
در ایران قاب های بتنی میان پر وجود دارد که نیاز به مقاوم سازی دارند. یکی از روش های موثر برای مقاوم سازی اینگونه ساختمان ها که در سال های اخیر مطالعات فراوانی در مورد آن انجام شده است، استفاده از کامپوزیت های مسلح فیبری (FRP) می باشد. در این تحقیق یک روش ساده به منظور تخمین سختی و ظرفیت بار نهایی قاب بتنی میان‌پر ارائه شده است. مصالح میانقاب به وسیله دو روش یک دستک و سه دستک، مدل سازی شده و با ...
[ 5 ] - Seismic Retrofitting RC Structures with Precast Prestressed Concrete Braces- ABAQUS FEA Modeling
Precast prestreesed concrete braces are a new method for seismic strength of Concrete Structures which has the following benefits: a) no wet concrete work in construction site b) No bolt or anchorage to the existing frame c) easy to apply d) short construction period e) low construction cost, to evaluate seismic performance of strengthened structure a model consist of existing frame and concret...
[ 6 ] - Seismic Evaluation and Retrofit of Gas Stations: Case Study
Iran is a country with high seismicity while Tehran, the capital city is home to more than 10 million people which are located on the highest seismic zone of the country. There exist 153 gas stations throughout the metropolitan which are constructed to old building codes with little or no attention to the seismic considerations. In this study which was supported by the National Oil Company, fir...
[ 7 ] - Earthquake Evaluation of the Non Structural Elements in a Thermal Power Plant
Non Structural elements such as mechanical, electrical and architectural elements always posses serious damage potentials during earthquakes. Degree of damage imposed by the non structural elements is not usually measured by the physical damages caused, but more so by the amount of the economical and functional disruptions created in a built environment. This phenomenon is enhanced where the fu...
[ 8 ] - Improved Behaviour of Accordion Metallic Dampers Affected by the Increasing Number of Layers
In recent years, thin-walled accordion tubes under axial cyclic loading due to their appropriate energy absorption mechanism and behavioral characteristics were suggested as hysteretic metallic dampers. The effectiveness of accordion metallic damper (AMD) to protect and mitigate the response of structures under seismic loading is well established both experimentally and analytically. In this pa...
[ 9 ] - The Effect of Tuned Mass Damper on Seismic Response of Building Frames with Uncertain Structural Characteristics
Tuned mass dampers (TMDs) could be used to absorb the input energy of the applied load, and reduce the response of the building frames. However, the effectiveness of TMD in reducing the response of the building frames could be affected by inherited uncertainties in the structural characteristics of the frames. In this study, in order to investigate the probabilistic response of steel moment-res...
[ 10 ] - The Effects of Internal and External Stiffeners on Hysteretic Behavior of Steel Beam to CFT Column Connections
This study focuses on performance of H-shaped steel beams to CFT column rigid connections. To this end, the effects of internal and external stiffeners on hysteretic behavior of connections were studied. Comparative numerical analyses carried out on eight different connections. To this end finite element models were prepared using ANSYS and nonlinear cyclic analyses carried out. Results of this...
[ 11 ] - Comparison of using Different Modeling Techniques on the Prediction of the Nonlinear Behavior of R/C Shear Walls
Abstract: Reinforced concrete shear walls have been used throughout the world as known resisting elements for the lateral wind and earthquake loads. They are mostly designed and constructed based on elastic calculations and therefore resulting in un-economical sections. In order to overcome this weakness, scientists have proposed different methodologies to account for the non linear behavior of...
[ 12 ] - Non-Linear Behavior of New (FSFN) Moment Resisting Connections in Comparison to the Existing KBB Connections in Steel Frames
After Northridge (1994) and Kobe (1995) earthquakes, several studies have been conducted to improve the seismic performance of steel structures. In this investigation, new steel moment-resisting connections (FSFN) developed by the authors, were studied by the non-linear numerical analysis. These connections were single-sided beam-to-column assemblies that are representative of exterior beam-to-...
[ 13 ] - The Effect of Local Damage on Energy Absorption of Steel Frame Buildings During Earthquake
Progressive collapse is a kind of failure in which whole or large part of a structure collapse when a local damage occurs and distributes to other parts. Many researchers focus on the column removal analysis and study of the structure behavior under effect of gravity loads, so these investigations are mostly carried out on the tall building. Earthquake inspections indicate structural element ca...
[ 14 ] - THEORETICAL AND NUMERICAL STUDY ON THE STRENGTHENED STEEL PLATE SHEAR WALLS BY FRP LAMINATES
In this paper, nonlinear behavior of strengthened steel plate shear walls (SPSWs) by FRP laminates theoretically and numerically has been investigated. In the first part, a new method, “the composite-plate frame Interaction (C-PFI) method”, has been introduced to predict the shear behavior of the composite steel plate shear wall systems (CSPSWs). In the second part, several models of one-story ...
[ 15 ] - SEISMIC BEHAVIOR OF SILOS WITH DIFFERENT HEIGHT TO DIAMETER RATIOS CONSIDERING GRANULAR MATERIAL-STRUCTURE INTERACTION
Silos are structures that are used for storing different types of granular material. Dynamic behavior of silos under seismic loads is very complex. In this paper seismic behavior of steel silos with different height to diameter ratios is investigated by considering granular material-structure interaction using ABAQUS finite element package. Silo wall is modeled by shell elements and its behavio...
[ 16 ] - Non-Linear Behavior and Shear Strength of Diagonally Stiffened Steel Plate Shear Walls
In this study, non-linear behavior of diagonally stiffened steel plate shear walls as a seismic resisting system has been investigated, and theoretical formulas for estimating shear strength capacity of the system have been proposed. Several validated analytical finite element models of steel shear walls with various stiffener dimensions are generated to verify and compare the analytical and th...
[ 17 ] - Seismic Damage and Disaster Management Maps (A Case Study)
There are many cities in developing countries that are built with minimal seismic considerations. Also, due to the expenses involved regarding detailed and analytical identification of such vulnerable buildings and structures in these cities, is very difficult and also time consuming. It is necessary and much needed to have a quick and inexpensive solution for such assessment in cities with the...
[ 18 ] - Effect of Link Slab on Seismic Response of Two Span Straight and Skew Bridges
Highway bridges are frequently constructed as simple span structures with steel or concrete girders and a cast-in-place concrete deck, spanning from one pier to another. At each end of the simple span deck, a joint is provided for deck movement due to temperature, shrinkage, and creep. Bridge deck joints are expensive and pose many problems with regard to bridge maintenance. Elimination of deck...
[ 19 ] - Tests to Determine the Joint Stiffness and Resisting Moment Capacity of Joints in Timber-Framed Houses
Wind and earthquake disasters in the world often cause billions of dollars of damage to buildings, most of which is to non-engineered buildings-especially homes. Wood-frame homes use connectors which exhibit partial rotational rigidity at the member ends, making analytical solutions difficult. This is due to the lack of information about the complex behavior of the connections used in this type...
[ 20 ] - Prediction of Engineered Cementitious Composite Material Properties Using Artificial Neural Network
Cement-based composite materials like Engineered Cementitious Composites (ECCs) are applicable in the strengthening of structures because of the high tensile strength and strain. Proper mix proportion, which has the best mechanical properties, is so essential in ECC design material to use in structural components. In this paper, after finding the best mix proportion based on uniaxial tensile st...
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