Hysteresis Behavior of Square Tube Columns to H-Beam Connections with Vertical Stiffeners

2005 ◽  
Vol 8 (6) ◽  
pp. 561-572 ◽  
Author(s):  
Jinan Chung ◽  
Seongyon Seo ◽  
Chiaki Matsui ◽  
Sungmo Choi
Keyword(s):  
Test Methods ◽  
Test Results ◽  
Moment Frames ◽  
Steel Moment Frames ◽  
Steel Moment Resisting Frames ◽  
Simply Supported ◽  
Moment Resisting Frames ◽  
Connection Method ◽  
Moment Resisting ◽  
H Beam

This paper deals with confirming the usability of a new connection method for steel moment-resisting frames. The connections are strengthened with vertical stiffeners to connect square tube columns and H-shaped beams. Two test methods were selected with experimental parameters given as details. The first test is performed under symmetrical loading. Beams are simply supported on both ends and test load is applied to the top of the column. The second test is performed under anti-symmetric loading. The shape of test specimens is cruciform, with a beam and a column. The top end and base of the column are simply supported, and load is applied to both ends of the beam. Test results are summarized to investigate structural performances of the connection. Nonlinear FE analysis using ANSYS for moment-resisting frames was performed to confirm the test results. It was found that all specimens had sufficient capacities exceeding the full plastic strength of beam. Therefore, the connections strengthened with vertical stiffeners were successfully verified to have possibility as a new connection method for steel moment-frames.

Amplified Seismic Loads in Steel Moment Frames

2016 ◽  
Vol 847 ◽  
pp. 222-232
Author(s):  
Bora Aksar ◽  
Selcuk Dogru ◽  
Bulent Akbas ◽  
Jay Shen ◽  
Onur Seker ◽  
...  
Keyword(s):  
Lateral Displacement ◽  
Ground Motions ◽  
Time History ◽  
Load Level ◽  
Steel Buildings ◽  
Moment Frames ◽  
Axial Loads ◽  
Steel Moment Resisting Frames ◽  
Moment Resisting Frames ◽  
Moment Resisting

This study focuses on exploring the seismic axial loads for columns in steel moment resisting frames (SMRFs) under strong ground motions. For this purpose, the increases in axial loads are investigated at the maximum lateral load level and the corresponding lateral displacement. The results are presented in terms of maximum amplification factors (Ω0) of all frame columns under the selected ground motions and axial load-moment levels in columns. four typical steel moment resisting frames representing typical low, medium and high rise steel buildings are designed based on the seismic design requirement in ASCE 7-10 and AISC 341-10 . An ensemble of ground motions range from moderate to severe are selected to identify the seismic response of each frames. Two sets of ground motions corresponding to 10% and 2% probability of exceedance are used in nonlinear dynamic time history analyses.

Effect of Column-Base Flexibility on the Seismic Response and Safety of Steel Moment-Resisting Frames

2013 ◽  
Vol 29 (4) ◽  
pp. 1537-1559 ◽  
Author(s):  
Farzin Zareian ◽  
Amit Kanvinde
Keyword(s):  
Nonlinear Response ◽  
Moment Frames ◽  
Steel Moment Frames ◽  
Steel Moment Resisting Frames ◽  
Four Frames ◽  
Plastic Mechanism ◽  
Fixed Base ◽  
Moment Resisting ◽  
Ductility Capacity ◽  
Column Base

The effect of column-base flexibility on the response of steel moment frames is assessed through parametric simulation. The response of four frames (2-, 4-, 8-, and 12-story), designed as per current codes, is investigated through static push-over simulations and sophisticated nonlinear response-history simulations, including collapse simulation. For each frame, a range of base fixities is interrogated, including realistic values that are calculated from the designed connections. The results indicate that a reduction in base fixity alters the force distribution and the plastic mechanism, significantly reducing ductility capacity and strength, as well as collapse resilience, while increasing member forces. For the 4-, 8-, and 12-story frames, this trend suggests that the expected response of such frames is worse than is implied by simulations and design approaches that assume a fixed-base condition. However, the trend is beneficial for the 2-story frame, which is analyzed and designed assuming a pinned base.

Performance-based assessment of seismic-resilient steel moment resisting frames equipped with innovative column base connections

Structures ◽  
2021 ◽  
Vol 32 ◽  
pp. 1646-1664
Author(s):  
Elena Elettore ◽  
Annarosa Lettieri ◽  
Fabio Freddi ◽  
Massimo Latour ◽  
Gianvittorio Rizzano
Keyword(s):  
Steel Moment Resisting Frames ◽  
Moment Resisting Frames ◽  
Performance Based Assessment ◽  
Moment Resisting ◽  
Base Connections ◽  
Column Base

Collapse risk of pre-Northridge tall steel moment-resisting frames in the Seattle basin during large-magnitude subduction earthquakes

2021 ◽  
Vol 244 ◽  
pp. 112751
Author(s):  
Carlos Molina Hutt ◽  
Shervin Zahedimazandarani ◽  
Nasser A. Marafi ◽  
Jeffrey W. Berman ◽  
Marc O. Eberhard
Keyword(s):  
Large Magnitude ◽  
Steel Moment Resisting Frames ◽  
Moment Resisting Frames ◽  
Subduction Earthquakes ◽  
Moment Resisting

Column Moment Demands from Orthogonal Beam Twisting

2018 ◽  
Vol 763 ◽  
pp. 259-269
Author(s):  
George Webb ◽  
Kanyakon Kosinanonth ◽  
Tushar Chaudhari ◽  
Saeid Alizadeh ◽  
Gregory A. MacRae
Keyword(s):  
Lateral Displacement ◽  
Frame Structure ◽  
Moment Frames ◽  
Steel Moment Frames ◽  
Element Analysis ◽  
Soft Storey ◽  
Simply Supported ◽  
Composite Frame ◽  
Explicit Consideration ◽  
Column Joint

Beam column joint subassemblies in steel moment frames often have simply-supported gravity beams framing into the joint in the perpendicular direction. When these subassemblies undergo lateral displacement, moments enter the column from the beams. Some of these moments are directly applied from the in-plane beam and slab stresses as they contact the column, and additional moments occur as the slab causes the perpendicular simply supported beams to twist. In most design codes around the world, no explicit consideration of these moments is performed even though they may increase the likelihood of column yielding and a soft-storey mechanism. This paper quantifies the magnitude of these perpendicular beam twisting moments in typical subassemblies using inelastic finite element analysis. It is shown that for beam-column-joint-slab subassemblies where the primary and secondary beams are fully welded to the column, the addition of slab effects significantly increases the total stiffness and strength of the composite frame structure. In addition to this, it is also shown the twisting moment demand of the secondary beams increased the frames strength by approximately 2% for an imposed drift of 5% for the subassembly investigated when no gap was provided between slab and the column. It was also shown the twisting moment demand of the secondary beams increased the frames strength by approximately 10% for a maximum imposed drift of 5% for the subassembly investigated when a gap was provided between the slab and the column.

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