Abstract
Limit-state strengths of I-shaped structural steel members at elevated temperatures are analytically investigated by using detailed finite shell element models. Elastic and inelastic flexural buckling and lateral-torsional buckling are simulated for the limit-states of columns and unbraced beams, respectively. The simulations are conducted using steel design properties at elevated temperatures described in Recommendation for Fire Resistant Design of Steel Structures and Eurocode 3, which are compared with existing test data by several researchers. Pursuing realistic and practical evaluation of structural performance, equations for column and unbraced beam strengths are proposed as functions of elevated temperatures and member length. The proposed strengths agree well with the simulation data using the steel properties from Eurocode 3, which are more representative of the test data. This member-based strength evaluation is expected for use as an alternative simple design approach for future limit-state design in structural fire engineering.
