الفهرس 
ACKNOWLEDGEMENTSOnly 14 pages are availabe for public view
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Abstract
Steel beam to concrete-filled steel tube (CFST) column connection is a key to exploite the superior advantages of steel ductility and concrete stiffness in moment-resisting frames (MRFs). A lack of fabrication experience, design guidelines, and prequalification connection details in modern-applicable codes are the obstacles threatening the worldwide spread of composite-moment resisting frames (C-MRFs) with CFST columns. For these reasons, an effort has been devoted to developing successful solutions that can alter thinking about the difficulty of the CFST connections, enhancing the simple behavior of the bolted top and seat angle connection, and assessing the resilience limit of the self-centering post-tensioned (SCPT) connection in correlation to the resilience state of the energy dissipation (ED) system.
Stepwise, four main topics were taken into account to fulfill these objectives. At the first, for more understanding of the problem depth, the available welded connections that have been experimentally examined in previous literature were subjected to a performance-based evaluation together with an intensive assessment of their general behavior. In light of the study, a novel concept of the diamond-shaped concrete-filled steel tube column (DCFST) connections has been introduced. Consequently, To shed light on the capability of the DCFST connecting concept to improve the seismic response of the directly welded connections to the concrete-filled steel tube (CFST) columns, two DCFST connection typologies were suggested. Accordingly, a prepared steel beam should be attached to the corner of a square CFST column rather than the column face for directly welded DCFST connection. In contrast, prepared welded-flange-plates (WFP) can be attached to the corner of the square CFST column upper and below the steel beam flanges prior to each plate fillet welded to the adjacent flange for the WFP-DCFST connection. The third topic has been dealt with integrating the post-tensioned fiber-reinforced polymer (FRP) bars into a simple top and seat angle connection to upgrade and enhance its seismic response. A novel semi-self-centering post-tensioned connection composed of post-tensioning FRP (PT-FRP) bars as well as the top and seat angles as an energy dissipation system was sophisticated for qualifying the known simple top and seat angle connection to withstand seismic events. Into the fourth topic, the resilience-based design for the advanced self-centering post-tensioned (SCPT) connection could be realized through an intensive numerical study for the correlation between the resilience SCPT system and the resilient limit of the ED system. For this purpose, more than 103 models of an innovative bolted compact circular hollow steel tube (CHST) were established. The extensive numerical study was culminated with extracting design charts for optimal adopting the ED geometry for ensuring a certain level of resilience.