scholarly journals FUNDAMENTAL STUDY FOR DEVELOPMENT OF TUBULAR DAMPERS FOR USE IN EXPOSED-TYPE COLUMN BASE OF STEEL MOMENT FRAMES

2012 ◽  
Vol 77 (678) ◽  
pp. 1329-1338
Author(s):  
Seiji MUKAIDE ◽  
Daiki IMOTO ◽  
Nobuhiro NAGAYAMA
Keyword(s):  
Moment Frames ◽  
Steel Moment Frames ◽  
Fundamental Study ◽  
Column Base

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.

scholarly journals DUCTILITY AND SHEAR RESISTING MECHANISM OF EXPOSED-TYPE COLUMN BASE WITH TUBULAR DAMPERS IN STEEL MOMENT FRAMES

2017 ◽  
Vol 82 (736) ◽  
pp. 897-907
Author(s):  
Seiji MUKAIDE ◽  
Yukitaka HAMADA ◽  
Keita UEMATSU ◽  
Ryousuke MURAOKA ◽  
Tsuyoshi HAGINO ◽  
...  
Keyword(s):  
Moment Frames ◽  
Steel Moment Frames ◽  
Column Base

Effects of Fling Step and Forward Directivity on Seismic Response of Buildings

2006 ◽  
Vol 22 (2) ◽  
pp. 367-390 ◽  
Author(s):  
Erol Kalkan ◽  
Sashi K. Kunnath
Keyword(s):  
Seismic Response ◽  
Ground Motions ◽  
High Amplitude ◽  
Moment Frames ◽  
Steel Moment Frames ◽  
Damage Potential ◽  
Near Fault ◽  
Forward Directivity ◽  
Fling Step ◽  
Far Fault

This paper investigates the consequences of well-known characteristics of near-fault ground motions on the seismic response of steel moment frames. Additionally, idealized pulses are utilized in a separate study to gain further insight into the effects of high-amplitude pulses on structural demands. Simple input pulses were also synthesized to simulate artificial fling-step effects in ground motions originally having forward directivity. Findings from the study reveal that median maximum demands and the dispersion in the peak values were higher for near-fault records than far-fault motions. The arrival of the velocity pulse in a near-fault record causes the structure to dissipate considerable input energy in relatively few plastic cycles, whereas cumulative effects from increased cyclic demands are more pronounced in far-fault records. For pulse-type input, the maximum demand is a function of the ratio of the pulse period to the fundamental period of the structure. Records with fling effects were found to excite systems primarily in their fundamental mode while waveforms with forward directivity in the absence of fling caused higher modes to be activated. It is concluded that the acceleration and velocity spectra, when examined collectively, can be utilized to reasonably assess the damage potential of near-fault records.

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