SENSITIVITY OF SPECIAL STEEL MOMENT FRAMES TO THE INFLUENCE OF COLUMN-BASE HYSTERETIC BEHAVIOR INCLUDING GRAVITY FRAMING SYSTEM

2020 ◽  
Author(s):  
Pablo Torres-Rodas ◽  
Francisco Flores ◽  
Bryam Astudillo ◽  
Sebastian Pozo
Keyword(s):  
Hysteretic Behavior ◽  
Moment Frames ◽  
Steel Moment Frames ◽  
Special Steel ◽  
Column Base

Assessment of floor accelerations in special steel moment frames

2015 ◽  
Vol 106 ◽  
pp. 154-165 ◽  
Author(s):  
Francisco X. Flores ◽  
Diego Lopez-Garcia ◽  
Finley A. Charney
Keyword(s):  
Moment Frames ◽  
Steel Moment Frames ◽  
Special Steel

Influence of the gravity framing system on the collapse performance of special steel moment frames

2014 ◽  
Vol 101 ◽  
pp. 351-362 ◽  
Author(s):  
Francisco X. Flores ◽  
Finley A. Charney ◽  
Diego Lopez-Garcia
Keyword(s):  
Moment Frames ◽  
Steel Moment Frames ◽  
Special Steel

scholarly journals Seismic Demands in Column Base Connections of Steel Moment Frames

2018 ◽  
Vol 34 (3) ◽  
pp. 1383-1403 ◽  
Author(s):  
Pablo Torres-Rodas ◽  
Farzin Zareian ◽  
Amit Kanvinde
Keyword(s):  
Time History ◽  
Base Plate ◽  
Moment Frames ◽  
Steel Moment Frames ◽  
Seismic Demands ◽  
Axial Forces ◽  
Plate Connections ◽  
Nonlinear Time History ◽  
Base Connections ◽  
Column Base

Methods for the seismic design of base connections in steel moment frames are well-developed and routinely utilized by practicing engineers. However, design loads for these connections are not verified by rigorous analysis. This knowledge gap is addressed through nonlinear time history simulations using design-level seismic excitation that interrogate demands in column base connections in 2-, 4-, 8-, and 12-story steel moment frames, featuring base connections that reflect current U.S. practice. The results indicate that: (1) for exposed base plate connections, lower bound (rather than peak) estimates of axial compression are suitable for design because higher axial forces increase connection strength by delaying base plate uplift; (2) even when designed as pinned (as in low-rise frames), base connections carry significant moment, which can be estimated only through accurate representation of base flexibility; and (3) the failure of embedded base connections is controlled by moment, which may be estimated either through overstrength or capacity-based calculations.

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.

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