Effect of gravity framing on the overstrength and collapse capacity of steel frame buildings with perimeter special moment frames
Effect of gravity framing on the overstrength and collapse capacity of steel frame buildings with perimeter special moment frames
This paper investigates the effect of the gravity framing system on the overstrength and collapse risk of steel frame buildings with perimeter special moment frames (SMFs) designed in North America. A nonlinear analytical model that simulates the pinched hysteretic response of typical shear tab connections is calibrated with past experimental data. The proposed modeling approach is implemented into nonlinear analytical models of archetype steel buildings with different heights. It is found that when the gravity framing is considered as part of the analytical model, the overall base shear strength of steel frame buildings with perimeter SMFs could be 50% larger than that of the bare SMFs. This is attributed to the gravity framing as well as the composite action provided by the concrete slab. The same analytical models (i) achieve a static overstrength factor, Ωs larger than 3.0 and (ii) pass the collapse risk evaluation criteria by FEMA P695 regardless of the assigned total system uncertainty. However, when more precise collapse metrics are considered for collapse risk assessment of steel frame buildings with perimeter SMFs, a tolerable probability of collapse is only achieved in a return period of 50 years when the perimeter SMFs of mid-rise steel buildings are designed with a strong-column/weak-beam ratio larger than 1.5. The concept of the dynamic overstrength, Ωd is introduced that captures the inelastic force redistribution due to dynamic loading. Steel frame buildings with perimeter SMFs achieve a Ωd>3 regardless if the gravity framing is considered as part of the nonlinear analytical model representation.
Collapse capacity, Dynamic overstrength, Gravity framing, Mean annual frequency of collapse, Shear tab connections, Steel SMF
1289-1307
Elkady, Ahmed
8e55de89-dff4-4f84-90ed-6af476e328a8
Lignos, Dimitrios G.
9f55ad65-7b12-4ad6-972c-5a967ec0497b
19 May 2015
Elkady, Ahmed
8e55de89-dff4-4f84-90ed-6af476e328a8
Lignos, Dimitrios G.
9f55ad65-7b12-4ad6-972c-5a967ec0497b
Elkady, Ahmed and Lignos, Dimitrios G.
(2015)
Effect of gravity framing on the overstrength and collapse capacity of steel frame buildings with perimeter special moment frames.
Earthquake Engineering & Structural Dynamics, 44 (8), .
(doi:10.1002/eqe.2519).
Abstract
This paper investigates the effect of the gravity framing system on the overstrength and collapse risk of steel frame buildings with perimeter special moment frames (SMFs) designed in North America. A nonlinear analytical model that simulates the pinched hysteretic response of typical shear tab connections is calibrated with past experimental data. The proposed modeling approach is implemented into nonlinear analytical models of archetype steel buildings with different heights. It is found that when the gravity framing is considered as part of the analytical model, the overall base shear strength of steel frame buildings with perimeter SMFs could be 50% larger than that of the bare SMFs. This is attributed to the gravity framing as well as the composite action provided by the concrete slab. The same analytical models (i) achieve a static overstrength factor, Ωs larger than 3.0 and (ii) pass the collapse risk evaluation criteria by FEMA P695 regardless of the assigned total system uncertainty. However, when more precise collapse metrics are considered for collapse risk assessment of steel frame buildings with perimeter SMFs, a tolerable probability of collapse is only achieved in a return period of 50 years when the perimeter SMFs of mid-rise steel buildings are designed with a strong-column/weak-beam ratio larger than 1.5. The concept of the dynamic overstrength, Ωd is introduced that captures the inelastic force redistribution due to dynamic loading. Steel frame buildings with perimeter SMFs achieve a Ωd>3 regardless if the gravity framing is considered as part of the nonlinear analytical model representation.
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e-pub ahead of print date: 14 November 2014
Published date: 19 May 2015
Keywords:
Collapse capacity, Dynamic overstrength, Gravity framing, Mean annual frequency of collapse, Shear tab connections, Steel SMF
Identifiers
Local EPrints ID: 433845
URI: http://eprints.soton.ac.uk/id/eprint/433845
ISSN: 0098-8847
PURE UUID: 99cdca7b-020b-4c4d-8330-17142ce45399
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Date deposited: 04 Sep 2019 16:30
Last modified: 16 Mar 2024 04:41
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Author:
Dimitrios G. Lignos
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