Shear Strength Estimation of Nonseismically Designed Exterior Beam–Column Joints Strengthened with Unsymmetrical Chamfers
Publication: Journal of Structural Engineering
Volume 150, Issue 11
Abstract
A practical strengthening strategy for nonseismically designed exterior beam–column joints (BCJs) has been proposed by installing an unsymmetrical chamfer on the soffit of the beam. Its feasibility and effectiveness have been validated by extensive experimental studies. In this study, the load transfer mechanism of an exterior BCJ with chamfer is further analyzed to establish an analytical model for joint shear strength. An additional strut is identified in the chamfer based on finite element analysis results, which serves as the secondary load transfer path in addition to the diagonal strut within the joint area. Furthermore, a parametric study was performed to correlate chamfer size with joint shear strength of a strengthened joint. Width of the diagonal strut is enlarged with increasing chamfer size, whereas the effective width of compression zone in the chamfer is limited. With identified load path of BCJ with chamfer, an analytical model is established based on softened strut-and-tie model (STM) which provides clear load transfer mechanism for rational conception design and reasonable join shear estimation, especially for unreinforced BCJs. Width of the diagonal strut, which is the main parameter in a STM, is redefined accounting for contribution of chamfer. Finally, design procedures and recommendations are provided for application of the strengthening strategy in practice.
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Data Availability Statement
Some or all data, models, or code that support the findings of this study are available from the corresponding author upon reasonable request.
Acknowledgments
The authors are grateful to the financial support from General Research Fund of the Hong Kong Special Administrative Region Government HKSARG (GRF No. 15210219), and technical support from Structural Engineering Research Laboratory, Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University.
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Published In
Journal of Structural Engineering
Volume 150 • Issue 11 • November 2024
Copyright
© 2024 American Society of Civil Engineers.
History
Received: Jul 19, 2023
Accepted: May 30, 2024
Published online: Aug 21, 2024
Published in print: Nov 1, 2024
Discussion open until: Jan 21, 2025
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