City Research Online

Abstract

Circular reduced web section (RWS) openings provide a practical weakening strategy for retrofitting welded steel moment connections by relocating inelastic demand away from the beam-to-column interface. This paper defines a compact suite of performance metrics for cyclic assessment of fully restrained circular RWS subassemblies subjected to AISC 341 cyclic loading protocol. A validated three-dimensional finite element model is used to generate a database of 7,575 numerical specimens spanning European IPE sections, steel grades S235, S275, and S355, and span-to-depth ratios 2L/h=6 to 14. Backbone-based ordinates and hysteresis-derived measures are proposed to quantify strength retention, high-drift stability. Database-level trends show that opening geometry primarily governs post-yield behaviour, with larger web openings and close to the column face most detrimental at low span to depth ratios. In addition, robust geometry corridors meet AISC criteria for special moment frames with less than 20% strength degradation while preserving stability. Selected well-proportioned openings can match or exceed solid web stability and high drift.

Publication Type:	Article
Additional Information:	© 2026 The Author(s). ce/papers published by John Wiley & Sons Ltd. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
Publisher Keywords:	reduced web section, circular web opening, welded moment connection, cyclic loading, performance metrics, backbone curve, seismic retrofit, finite element analysis
Subjects:	T Technology > TA Engineering (General). Civil engineering (General)
Departments:	School of Science & Technology School of Science & Technology > Department of Engineering
SWORD Depositor:	Symplectic Administrator

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