2017 Annual Stability Conference Preview

Session S2 – Seismic Stability of Members and Systems
Wednesday, March 22, 2017
9:45 am

Using Longitudinal Stiffeners to Mitigate Buckling of Noncompact and Slender Beam Webs in Ductile Moment Frame Connections

Typical beam sections used in metal buildings have noncompact or slender webs.  It is often difficult, therefore, for these economically designed deep built-up members to meet highly ductile or moderately ductile web slenderness (h/tw) requirements in the AISC Seismic Provisions for use in special or intermediate moment resisting frame connections.  A combined experimental and computational research program has been conducted to investigate a design strategy whereby longitudinal web stiffeners are used to break the web into panels which individually satisfy ductile slenderness requirements.  Full-scale cyclic tests on three 1219 mm (48 in.) deep end plate moment connection subassemblage specimens demonstrate the effectiveness of this design strategy.  A computational study using finite element models validated against the full-scale experiments is used to extend the applicability of the results.  It is shown that moment connections with longitudinal stiffeners can develop substantial ductility and satisfy qualification requirements for special moment resisting frame connections even if the beam web outside the connection region is noncompact or slender.

Matthew R. Eatherton, Yujia Chen and Thomas M. Murray, Virginia Polytechnic Institute and State University, Blacksburg, VA; Karim Laknejadi, Iran University of Science and Technology, Tehran, Iran

2017 Annual Stability Conference Preview:

Session S2 – Seismic Stability of Members and Systems
Wednesday, March 22, 2017
9:45 am

Stability Requirements of Deep Steel Wide-Flange Columns under Cyclic Loading

This research investigates the hysteretic behavior of deep wide-flange steel columns that are typically used in steel moment-resisting frames (MRFs) in North America. This is achieved through an extensive parametric study using a validated continuum finite element (FE) modeling approach. Based on the FE results, the cyclic deterioration in the column flexural strength and stiffness is evaluated. Accordingly, design recommendations are developed related to the seismic compactness criteria for highly ductile members such that column axial shortening can be reduced under design basis and low-probability of occurrence earthquakes. Furthermore, empirical equations are developed for predicting the out-of-plane force demands and the plastic hinge length in steel wide flange columns.

Ahmed Elkady and Dimitrios G. Lignos, Swiss Federal Institute of Technology, Lausanne (EPFL), Switzerland

 

Join us at the world’s only annual conference focused exclusively on the important role of structural stability in structural engineering. The SSRC Annual Stability Conference (ASC) is held every year as an exclusive track within AISC’s NASCC: The Steel Conference. This conference brings together researchers from around the world to report and discuss the latest research in structural stability. The 3.5 day conference begins on Tuesday afternoon, a day before the formal start of the NASCC, with sessions consisting of research presentations as well as meetings of the SSRC Task Groups. Register now.