Future Hot-Rolled Asymmetric Steel I-Beams

Abstract

The purpose of the presented research is to evaluate the potential future manufacturing of hot-rolled asymmetric I-beams (AIBs) for construction in building floor systems. This technical note presents some of the primary manufacturing and structural challenges. A feasibility study is conducted to numerically evaluate the potential impact of AIBs. The first part of the study investigates composite behavior of AIBs in the final constructed state. As expected, an increase in flexural strength was observed, along with a decrease in deflections. Both are clear advantages of AIBs. The second portion of the feasibility study focuses on the noncomposite section behavior during construction. Stability concerns are present for unbraced lengths typically seen during construction. The primary finding was the benefit of reducing the thickness versus reducing the width of the top flange. Future AIB dimensions should consider thin top flanges with sufficient width to maintain adequate lateral-torsional buckling and local buckling strength. The latter portion of this technical note presents future direction of the research to comprehensively understand the behavior of hot-rolled AIBs. The focus is on extensive numerical simulation studies validated through full-scale laboratory experiments. The experiments are to be conducted on proof-of-concept AIBs produced by Nucor steel. The validated numerical modeling approaches will then be utilized for larger parametric studies to develop cross-section proportional limits (e.g., width-to-thickness ratios). These limits will be used to establish specific AIB cross-section dimensions.