Experimental Research on the Calculating Method of Stress Concentration Factor for CFST K-Joint
Publication: Journal of Structural Engineering
Volume 149, Issue 3
Abstract
The concrete-filled steel tubular (CFST) K-joint was taken as the research object, full-scale specimen tests and finite-element (FE) analysis of seven CFST K-joints and one steel tubular (ST) K-joint were carried out. The accuracy of CFST K-joint stress concentration coefficient (SCF) calculation using the existing K-joint SCF formula was discussed. Based on the effect of core concrete on the chord deformation mechanism, the releasing coefficient of CFST K-joint SCF was proposed. According to the relationship between releasing coefficient and stripping arc length, the calculation method of releasing coefficient was established by theoretical derivation. The calculation method of CFST K-joint SCF was then established based on the releasing coefficient and ST K-joint SCF. The obtained results show that the maximum SCF of the K-joint appears in the position of the intersecting weld between tension brace and chord near the crown toe of the chord. The maximum SCFs of the CFST and ST K-joints in order are obtained as 3.98 and 6.08, which indicates that the core concrete can reduce the SCF of the CFST K-joint by about 34.5%. The existing methods for calculating the SCF of CFST and ST K-joints fail to fully consider the influence of core concrete constraints and the coupling relationship between geometric parameters; therefore, the accuracy of CFST K-joint SCF calculation using the existing K-joint SCF calculation formula is low. By employing the proposed SCF calculation method, the calculation error of the CFST K-joint SCF can be reduced from 58.0% to 19.6%.
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Data Availability Statement
All data, models, and code that support the findings of this study can be made available from the corresponding author upon reasonable request.
Acknowledgments
The authors would like to acknowledge the support from the National Key Research and Development Program of China (Grant No. 2017YFE0130300), the support from the National Natural Science Foundation of China (Grant No. 52078137), and the support from the Natural Science Foundation of Fujian Province (Grant No. 2019J06009). Any opinions, findings, and conclusions or recommendations expressed in this paper are those of the authors and do not necessarily reflect the views of the sponsors.
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Information & Authors
Information
Published In
Journal of Structural Engineering
Volume 149 • Issue 3 • March 2023
Copyright
© 2023 American Society of Civil Engineers.
History
Received: Jan 24, 2022
Accepted: Nov 3, 2022
Published online: Jan 5, 2023
Published in print: Mar 1, 2023
Discussion open until: Jun 5, 2023
ASCE Technical Topics:
- Composite materials
- Concrete
- Engineering fundamentals
- Engineering materials (by type)
- Field tests
- Finite element method
- Full-scale tests
- Joints
- Materials engineering
- Metals (material)
- Methodology (by type)
- Numerical methods
- Steel
- Stress (by type)
- Stress analysis
- Structural analysis
- Structural engineering
- Structural members
- Structural systems
- Tests (by type)
- Tubes (structure)
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