Research Spotlight: DSM Design of Cold-Formed Steel Columns Failing in Distortional Modes at Elevated Temperatures

SSRC 2017 Annual Meeting Presentation

Session SS2B: Technical Presentations: Stability at Elevated Temperatures
Tuesday, March 21, 2017
3:15 p.m.

DSM Design of Cold-Formed Steel Columns Failing in Distortional Modes at Elevated Temperatures

This paper extends the scope of previous work by the authors aiming at investigating the structural behavior, strength and Direct Strength Method (DSM) design of cold-formed steel columns failing in distortional modes at elevated temperatures – the temperature-dependent steel constitutive law is based on the EC3-1.2 model. The new results concern pin-ended and fixed-ended columns displaying four cross-section shapes (lipped channels, hats, zeds and racks), with various dimensions, subjected to 7 elevated temperatures (up to 800ºC) and also ambient temperature (for comparison purposes). On the basis of the failure load data obtained in this work, it is first shown that the current DSM distortional design is unable to handle adequately distortional failures at elevated temperatures. Then, a modified DSM design approach is proposed: it consists of incorporating a temperature-dependent reduction factor ratio, based on the EC3-1.2 model, in the existing strength curve – the modified design curves are shown to provide adequate (reliable and mostly safe) failure load predictions for the set of columns under consideration.

Alexandre Landesmann and  Fernanda Cristina Moreira da Silva, Federal University of Rio de Janeiro, Brazil; Dinar Camotim, University of Lisbon, Lisbon, Portugal