Stress-Concentration Factors in Circular Hollow Section and Square Hollow Section T-Connections: Experiments, Finite-Element Analysis, and Formulas
Publication: Journal of Structural Engineering
Volume 139, Issue 11
Abstract
Nodal T-connections made up of circular hollow section (CHS) braces and square hollow section (SHS) chords (CHS-SHS T-connections) have the advantage that they do not require complex brace end preparation when compared with CHS-CHS T-connections. The stress-concentration factors (SCFs) in CHS-SHS T-connections have also been found to be lower than those in SHS-SHS T-connections by previous researchers. At present, no parametric equations have been developed for determination of SCFs for the design of CHS-SHS T-connections. In this investigation, eight CHS-SHS T-connections with unique nondimensional parameters were strain gauged for determination of strain-concentration factors (SNCFs) and therefore SCFs. A three-dimensional finite-element model was then developed using the ANSYS software to simulate the stress distribution at the brace-chord welded interface under axial force and in-plane bending in the brace. Validation of the model was carried out by comparing the SNCFs determined from the experiment and those determined from the finite-element model. It was found that the finite-element models were able to capture both the maximum SNCF in the connection and the SNCF distribution around the brace-chord welded interface. A parametric study was carried out to determine the SCFs for numerous models with unique nondimensional parameters , , and . Using multiple regression analysis, equations have been developed for SCFs at hot spots around the CHS-SHS T-connections under the loads axial force in the brace and in-plane bending in the brace. There is good agreement between the maximum SCFs in the CHS-SHS T-connections calculated by the resulting formulas and the maximum experimental SCFs in the connections.
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Acknowledgments
The authors thank the Natural Science Foundation of China for financially supporting the research in this paper through Grant No. 50478108. This paper was written during the third author’s Guang Hua Education Foundation Fellowship at Tongji University from December 18, 2010, to March 17, 2011. The third author is grateful to Tongji University and, in particular, to his host, Professor Lewei Tong, for his kind hospitality and support during this period.
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© 2013 American Society of Civil Engineers.
History
Received: Mar 22, 2012
Accepted: Oct 16, 2012
Published online: Oct 19, 2012
Published in print: Nov 1, 2013
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