The Seismic Behavior of Wide-Flange Steel Columns:
Recent Experimental and Numerical Research Findings

NHERI Lehigh Seminar Series
November 21, 2019 | 12pm - 1pm EST

Abstract

In modern construction practice, deep and slender wide-flange column cross-sections (? W16) are commonly utilized in the seismic design of steel moment-frame buildings. While these members promote economy, potential local and global stability issues, accentuated by their geometry, raise concerns about their structural integrity (loss in strength, stiffness and plastic deformation capacity) under cyclic loading. This webinar presentation covers recent coordinated experimental and numerical research aimed at understanding and characterizing the hysteretic behavior of wide- flange steel columns.

The presentation is divided into two parts. The first one summarizes key findings from two experimental programs of wide-flange steel columns under multi-axis cyclic loading. This includes insights into the effects of member-end boundary conditions and lateral/axial loading histories on the column’s seismic performance. The experimental data are effectively used to provide potential improvements in current seismic provisions. To complement the available column test data, a series of parametric finite-element (FE) simulations were also conducted.

The second part summarizes key features of the high-fidelity FE modeling approach and its validation. The generated dataset is used to develop empirical expressions to prognosticate various column performance indicators, such as the column plastic hinge length and the expected column axial shortening. To help bridge the gap between state-of-the-art research and engineering practice, the dataset was also used to assess available nonlinear modeling guidelines in North America. New modeling criteria are developed for the first-cycle envelope and monotonic backbone curves of steel wide-flange columns in support of performance-based seismic evaluation of new and existing steel structures.

Presenter

Dr. Ahmed Elkady is a Lecturer in Structural Engineering within the National Infrastructure Laboratory at the University of Southampton, UK, since August 2019. Prior to that, he was a post-doctoral research scientist at École Polytechnique Fédérale de Lausanne, Switzerland. He holds MSc (2011) and PhD (2016) degrees from McGill University, Canada. Through integrated experimental, numerical and analytical research, Dr. Elkady’s research focuses on quantifying structural robustness metrics, such as collapse/demolition risk and direct economic losses, of steel and composite steel/concrete structures under multi-hazards. His past research has contributed to the North American seismic design provisions and the nonlinear modelling guidelines related to steel moment-resisting frame systems.

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