DEFORMATION LIMITS AND ROTATIONAL CAPACITIES FOR CONNECTIONS UNDER COLUMN LOSS

Published

October 12, 2016

Author(s)

Jonathan Weigand, Joseph Main

Abstract

For structural steel framing systems subjected to column loss, the ultimate gravity load carrying capacity of the system is often controlled by the rotation and deformation capacities of the connections within the affected bays. Within current design specifications, the potential for disproportionate collapse in structural design is evaluated by notionally removing critical load supporting elements from the structure, and designing the structure to sustain the applicable gravity loads without collapse via the alternative load path analysis method. Steel gravity framing systems subjected to column loss undergo large vertical deflections under gravity loads that induce large rotation and axial deformation demands on the connections. However, the acceptance criteria currently used to evaluate connection failure in alternative load path analysis are based on results from seismic testing that do not reflect the large axial demands imposed on the connections. Recent experimental data has shown that application of these rotation limits to column loss scenarios in steel gravity framing systems can be non-conservative. In this paper, experimental data from steel single-plate shear connections tested under column loss are compared to the rotation limits provided in ASCE/SEI 41 13 and UFC 4 023 03, and the factors influencing the widely varying levels of conservativism for different connection geometries are explained. A new approach for calculating acceptance criteria for steel gravity connections under column loss is also introduced. The new approach provides more risk consistency and accounts for the important influence of axial deformation demands on the connections.

Proceedings Title

Proceedings of the Eighth International Workshop on Connection in Steel Structures (Connections VIII)

Conference Dates

May 24-26, 2016

Conference Location

Boston, MA, US

Conference Title

Eighth International Workshop on Connection in Steel Structures (Connections VIII)

Pub Type

Conferences

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Citation

Weigand, J. and Main, J. (2016), DEFORMATION LIMITS AND ROTATIONAL CAPACITIES FOR CONNECTIONS UNDER COLUMN LOSS, Proceedings of the Eighth International Workshop on Connection in Steel Structures (Connections VIII), Boston, MA, US, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=921443 (Accessed December 30, 2024)