Section Capacity of Thin-Walled I-Section Beam-Columns

Abstract

This paper describes two series of tests performed on slender I-sections fabricated from high-strength steel plates by welding. Eight tests were conducted on each series. The objectives of the test program were: (1) to determine the section capacities and the shape of the interaction curves for two slender I-sections subjected to compression and major axis bending; and (2) to compare the results with design strength predictions by codes of practice. The study focused on the shape of the interaction curves and whether the curves used in the main codes of practice, which are largely based on compact or semicompact cross sections, are also applicable to slender cross sections. Generally, the design axial and bending section capacities predicted by the main codes of practice were conservative, as were the design interaction curves. The experimental interaction curves were close to linear for both test series. This is in agreement with the design interaction curves given by the Australian, British, and European specifications for steel structures. However, the use of a bilinear interaction curve, as stipulated in the American specification, was not evident in the test results.