Document Type : Article
Authors
1
Faculty of Engineering Hakim Sabzevari University
2
Faculty of Civil Engineering University and Research, Khorasan Razavi
3
Faculty of Engineering Alzahra University
Abstract
Formerly, because of the ease to run and more economical advantage, used widely in steel structures, despite of ambiguities in the nature of the modeling and seismic behavior of the Saddle connections. As expected semi-rigid behavior of these connections, was modeled, designed, and run in detail. In the past decade, large volumes of the construction structures have done with Saddle connections, which the majority of them need for improvement and reinforcement. The need for reinforcement of these structures, make the behavior and function cognition of this connections inevitable. However, many studies have done in this field, but there are a few researches about Saddle connections behavior under both gravity and lateral loads. Although, the gravity load may affect the seismic behavior parameters of this connection. In this paper, the contemporary effects of gravity and lateral loads are studying in various Saddle Kike connections samples. For this, analysis doing nonlinear. First, drawing the moment-rotation curve of the connection under cycle lateral and gravity loads, and for gain to the primary and the secondary hardness of the connection, drawing Push and Hysteresis curves. Also, calculating the maximum Von Mises stress $((\sigma v)max)$, max Hydrostatic stress $((\sigma n)max)$, the max Equivalent plastic strain (PEEQmax) for prop, pillar, critical weld lines, and up and down cornerstones, in connection parts. Finally, determining the Three-axial (TI) and Equivalent plastic strain (PEEQI) Indexes for connections comparison.Some results of recent study, after survey and comparison of model connections:1−Increasing the cornerstone length size ratio and so, increase of the prop section's elastic module cause to inconspicuous the gravity load effect on connection behavior characteristics (primary hardness, secondary hardness and surrenders moment).2−Survey of the TI rapture index in the studied samples cleared that upper cornerstone length increasing, however, increase connection hardness, but according to TI index, the pillar failure possibility in connection state significantly increases. Also, the increasing of the pillar high, noticeably increases this index in pillar connection.3−With a survey of the PEEQI rupture index in the studied samples cleared which has not significant value in different pillars.
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