EBS-ConXL steel connection system: A novel approach for SMRF applications
|
Researchers |
Ali Zohdi, Mahmoud Ali, Seyed Rasoul Mirghaderi and Seyed Mehdi Zahrai |
|
Published in |
Structures, volume 86 (April 2026), article 111329, February 2026. |
|
Abstract |
Steel moment-resisting frames utilizing modular ConXL collar connections typically require reduced beam section (RBS) modifications, yet the compatibility between ConXL components and alternative hinge-relocation strategies remains unexplored. This study presents the first systematic investigation of the Enlarged Beam Section (EBS) approach integrated with ConXL, examining how EBS geometric parameters influence stress distribution in collar assemblies, column panel zones, and critical welds. A parametric finite element analysis was performed, encompassing ten configurations to systematically investigate the effects of varying enlarged beam section (EBS) dimensions, plastic hinge locations, and a range of moment capacity-to-demand ratios (????∕????). Models evaluated ConXL collar flange stresses, column panel zone behavior, and CJP weld integrity under AISC 341 cyclic loading. Results reveal that optimizing EBS geometric parameters reduces critical stress concentrations in ConXL collar flanges by 13–33%, with the largest reductions at the collar flange inner corner and CJP weld interface. Increasing ????∕???? from 1.0 to 1.2 through flange width enlargement decreased weld line stresses by 18% in short-distance configurations and 13% in long-distance configurations, while maintaining column panel zone elasticity. Critically, plastic hinge location exhibited minimal influence on ConXL component stresses, whereas enlarged flange width proved dominant in governing collar system stress distribution. All configurations met qualification requirements for Special Moment Resisting Frames (SMRFs) per AISC 341 and FEMA 350, achieving 6% drift without exceeding 20% strength degradation and extending ultimate failure to 9% drift. These findings establish design guidelines for SMRF-qualified EBS-ConXL integration, demonstrating that ????∕???? ratios of 1.1–1.2 optimize ConXL collar performance. The study provides the first quantitative evidence that EBS parameter optimization enhances ConXL component longevity while maintaining SMRF qualification criteria. Key words: Enlarged Beam Section (EBS), ConXL, SMRF, Steel connection, Energy dissipation. |
|
Link to abstract |
