DAM as a primary method of structural steel design for stability

Abstract

Transitioning from a method that does not account for all types of loads, geometric imperfections, and construction flow to a reliable method; the best way is to evaluate their feasibility by design practice. This paper displays a comparative analysis of Effective Length Method (ELM) and Direct Analysis Method (DAM) as the main approaches to stability analysis and design of steel structures. Afterward, the paper detailed the DAM application with second-order analysis to account for P-Δ and P-δ effects, notional load for geometric imperfection, and flexural and axial stiffness reduction to account for inelastic effects. Verification on a 10-story building illustrated DAM to be more comfortable, faster, and ensuring that second-order effects are entirely performed. As the ELM is limited to Δ2nd order/Δ1st order < 1.5, the design analysis check results illustrate that second-order analysis in the DAM leads to a feasibility analysis of ELM.