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EVALUATION OF COLUMN-TREE MOMENT RESISTING CONNECTION WITH END PLATES AND HAUNCHED BEAM (RESEARCH NOTE) A. Bahaarmast and J. Razaaghi Abstract The column-tree constructional schemes allows for a reliable and convenient erection of moment resisting steel frames. Strengthening of column-tree connection with a haunch part can significantly improve seismic behavior of whole system. In the current study behavior of column-tree connections with haunched beams and end plate splices have been investigated. Special attention was paid for evaluation of the effect of haunch section length and presence of the beams bottom flange. Nonlinear finite element analysis has been used for numerical analyses. The results indicate an improvement of the load bearing capacity of specimens when a longer haunch was used and also when beam bottom flange existed in the haunch part. A direct relation between haunch length and the amount of stress in splice plates was also observed. However all connections showed ductile behavior during cyclic analysis, specimens with longer haunch revealed more desirable behavior. It was concluded that despite some deficiencies observed during the numerical tests, in presence of a longer haunch and also the beam\'s bottom flange, a noticeable improvement of the general behavior of connection can be achieved. Keywords Column-Tree Connection, Haunch, Splice Plate, Finite Element Analysis, Ductile Behavior چکیده مطالعه ی حاضر رفتار اتصال ستون- درختی تقویت شده با ما هیچه را تحقیق می کند. هدف اصلی مطالعه دریافت میزان تأثیر طول ماهیچه و نیز وجود یا عدم وجود بال پایین تیر در رفتار اتصال می باشد. اتصال ستون- درختی یکی از طرح های اجرایی سازه ای است که به دلیل محاسنش اخیراً بیشتر مورد استفاده قرار می گیرد. تقویت اتصال ستون- درختی با ماهیچه سبب بهبود رفتار اتصال شده و احتمال رفتار شکل پذیر مورد نظر را در آن افزایش می دهد. در این تحقیق جهت دست یابی به نتایج از تحلیل اجزای محدود غیر خطی استفاده شده است. نتایج تحقیق نشان می دهد که در صورت استفاده از ماهیچه های بلندتر و حضور بال پایین تیر ظرفیت باربری نمونه ها بهبود می یابد. رابطه ی مستقیم بین طول ماهیچه و میزان تنش های ورق های اتصال نشان داده شد. اگرچه توانایی رفتار شکل پذیر تمامی نمونه ها با ارزیابی رفتار چرخه ای آن ها مشاهده شد، نمونه های دارای ماهیچه ی بلندتر رفتلر بهبودیافته تری از خود نشان دادند. با وجود برخی نتایج نا مناسب، این نتیجه گرفته شد که استفاده از ماهیچه های بلند تر و وجود بال پایین تیر درحالت کلی باعث بهبود رفتار نمونه می گردند. منبع دانلود 28-12-2.pdf

Mechanical properties of Semi-Rigid Steel Frame- Braced Steel Plate Shear Wall Due to mechanical performances of brace and steel plate, mechanical properties of semi-rigid joints and its construction and installation, semi-rigid steel frame-braced steel plate shear wall system is proposed. Nonlinear static analysis with parameters (thickness of plate, type of brace, size of brace and the ratio of span to height) changed of a single-span and single-floor semi-rigid steel frame-braced steel plate shear wall system illustrates that braced steel plate shear walls contributes obviously to bearing capacity and lateral rigidity of semi-rigid steel frame. Also, the finite element analysis (by ANSYS) show that semi-rigid steel frame-braced steel plate shear wall system has excellent ductility. AMR.1120-1121.1516.pdf

Pillow-Shape Base Isolation System and Its Seismic Behavior Ali Tayaran; Mahmood Hosseini In this paper a new isolating system is introduced for short to mid-rise buildings. In comparison to conventional systems such as LRB and HRB, the proposed system has the advantage of no need to cutting edge technology and has low manufacturing cost. This system is made up of two orthogonal pairs of pillow-shaped rollers that are located between flat bed and plates. By using this system in two perpendicular directions, building can move in all horizontal directions with respect to its foundation. Due to the pillow shape of the roller, this system has self-centering capability which causes it to return to its original position after the earthquake. The rolling friction force between pillows and their bed creates some damping in the system which prevents it from further oscillation after earthquake excitations diminish. The purpose of this study is to evaluate the proposed isolation system’s performance under different earthquake excitations. First of all general features of the proposed isolators have been introduced followed by the analytical equations of the system. Vertical bearing capacity and the effects of the thickness of pillows has been investigated using ABAQUS software. It has been shown that for a pair of pillows of 58 cm width, 45 cm height and 100 cm length the vertical load bearing capacity of the system is more than 300 tons. The period of system with respect to the height and radius of curvature of the rollers, and seismic response of a building, assumed as a rigid body resting on isolators, has been studied subjected to simultaneous effects of horizontal and vertical excitations. It has been shown that the proposed system can reduce the absolute acceleration in the building around 78% in average, while the building’s maximum displacement is around 1.77 times of the ground in average. منبع دانلود JSEG401435606200.pdf

Behavior of Unstiffened Steel Plate Shear Wall with Simple Beam-to-column Connections and Flexible Boundary Elements Dipti Ranjan Sahoo*, Balsher Singh Sidhu, and Arunesh Kumar Department of Civil Engineering, Indian Institute of Technology Delhi, New Delhi-110016, India Abastract This study investigates the effect of type of beam-to-column connections on the overall performance of steel plate shear wall (SPSW) systems under lateral loading condition. An analytical study using finite-element analysis has been conducted on a twostory SPSW system with rigid and pinned beam-to-column connections having constant panel aspect ratio and plate slenderness ratio. All boundary elements are designed as per the current code provisions. The influence of the type of connections between the web plates and the boundary elements on the overall performance of SPSW systems is also studied. In addition, the behavior of SPSW system with flexible boundary members along with pinned beam-to-column connections is also investigated under lateral loading condition. An experimental study has been carried out on a two-story SPSW specimen with flexible boundary elements to investigate its overall performance under the slow-cyclic loading. Based on the analytical and experimental results, various design issues of SPSW systems are discussed. Keywords: boundary elements, cyclic loading, experimentation, finite element analysis, steel plate shear wall 10.1007_S13296-015-3005-5-Behavior-of-unstiffened-steel-plate-shear-wall-with-simple-beam-to-column-connections-and-flexible-boundary-elements.pdf