HSS Research
The Steel Tube Institute sponsors the engineering research projects summarized below. These projects aim to advance HSS design and fabrication, with each project serving to inform and strengthen code equations and design approaches.
Cold-Formed Steel Framed Shear Walls Using HSS End
This research, co-sponsored by the Steel Tube Institute and the Steel Framing Industry Association (SFIA), will utilize full-scale shear wall tests performed by Dr. Cheng Yu of the University of North Texas. Cold-formed shear walls using hollow structural section (HSS) end posts will be investigated under both monotonic and cyclic tests to determine the structural performance and determine the shear capacity of the shear wall system.
Rectangular HSS Bolted End-Plate Connections Under Bending Moment
Guidance to design rectangular HSS end-plate splice connections historically focused on the axial tension load case, with design models for both two- and four-sided rectangular HSS bolted end-plate connections. Prior to this research, current standards did not offer guidance for the design of these connections under bending. With support from the Steel Tube Institute, Dr. Jeffrey Packer from the University of Toronto reviewed past experimental results and conducted yield-line analyses and finite element numerical studies to determine design methods for square and rectangular HSS end-plate connections under both bending and combined tension and bending, utilizing both two-sided and four-sided connection configurations.
Laser Cut Technology
This research project led by Dr. Alper Kanyilmaz, Associate Professor at Politecnico di Milano, with a consortium of partners including the Steel Tube Institute, aims to bring Laser-Cutting Technology (LCT) research into practice through international codification efforts and the development of practical design and detailing tools. LCT has the potential to reduce HSS fabrication and welding time through automation.
Tube in Tube Buckling Controlled Brace Research
This ongoing research, sponsored by the Steel Tube Institute (STI) and AISC, investigates the effectiveness of encasing an HSS brace in another HSS to form a tube-in-tube buckling-controlled brace (TnT BCB). The encasing outer HSS is responsible for providing continuous lateral support and expected to prevent global buckling while delaying local buckling, without contributing to the load-carrying capacity of the inner HSS brace. The physical testing and finite-element analyses are performed by principal investigators, Professor Jay Shen, Associate Professor, Iowa State University and Professor Onur Seker, Associate Professor, Gebze Technical University.
Investigation of Local Slenderness Limits for Hollow and Concrete-Filled HSS Members used as Braces – Phase 1
Dr. Dawn Lehman at the University of Washington, in collaboration with the Steel Tube Institute and American Institute of Steel Construction (AISC), and supported by Steel Tube Institute member producers, has completed vital research to investigate how local slenderness limits influence the design and behavior of braces made from Hollow Structural Section (HSS) in construction. This initiative, building on prior University of Washington research, seeks to provide insights crucial for an AISC Ad Hoc Task Group working on slenderness limits and modifications to the AISC 341-22 Specification. By conducting comprehensive physical tests on various HSS brace sizes and shapes, the study aims to establish appropriate seismic design width-thickness slenderness limits for highly and moderately ductile HSS braces. Physical testing, computational parametric studies, and full-system analysis for Phase 1 were completed in 2024, and a report published in the AISC Engineering Journal. The full-system braced frame analysis was conducted with a joint research program led by Andrew Sen, Marquette University. The findings from these projects were the basis for width-thickness limits proposed for the 2027 Seismic Specification (AISC 341) Table D1.1, broadening the range of HSS braces permitted for use in seismic applications. The generous contribution of HSS for testing by Steel Tube Institute member producers plays a significant role in facilitating this investigation.
Lehman, D., Khaldestad, J., Bergendahl, W., Sen, A., Berman, J., Roeder, C. 2024. “Inelastic Deformation and Local Slenderness Requirements for Rectangular HSS Braces”, Engineering Journal, AISC, Vol. 61 No. 1, 025-046
Rational Seismic Compactness Limits for HSS Members in Seismic Moment and Braced Frames – Phase 1
At the University of California – San Diego, supported by the Steel Tube Institute and American Institute of Steel Construction, Principal Investigator Dr. Chia-Ming Uang with Dr. Jason McCormick investigated how local slenderness limits impact Hollow Structural Section (HSS) columns and beams in seismic moment and braced frames. Physical testing and computational parametric studies for Phase 1 were completed in 2024, and a report published in the AISC Engineering Journal. The findings from this project were the basis for highly and moderately ductile width-thickness limits proposed for the 2027 Seismic Specification (AISC 341) Table D1.1, broadening the range of HSS columns and beams permitted for use in seismic braced frames and moment frames. The generous donation of HSS materials from the Steel Tube Institute members were vital to the completion of this important research. The outcomes are expected to refine industry standards and influenced changes to the AISC Specifications to pave the way for advancement of HSS in seismic construction.
Liu, J., C. 2024. “Seismic Local Buckling Limits for Hollow Structural Section and Built-Up Box Columns”, Engineering Journal, AISC, Vol. 61 No. 4, 217-228
Hidden Toe Welds in RHS-to-RHS Overlapped K-Connections
Dr. Jeffrey Packer, the Bahen/Tanenbaum Professor of Civil Engineering at the University of Toronto, has accomplished groundbreaking research on welded trusses, supported by the Steel Tube Institute. Focusing on the impact of welding or not welding the hidden toe of the overlapped branch in overlapping HSS K-Connections, this study is detailed in the article “Overlapped HSS K-Connections: To Weld or Not Weld the Hidden Toe?” Alongside this publication, formal research reports are referenced in the ‘Reference’ section of the STI article, providing an in-depth understanding of this critical investigation into welded trusses.
RHS-to-RHS Zero-Gap K-Connections
Dr. Jeffrey Packer, the Bahen/Tanenbaum Professor of Civil Engineering at the University of Toronto, led groundbreaking research on welded trusses, made possible through sponsorship from the Steel Tube Institute. One of the primary investigations in this research centered on evaluating the impact of providing zero gap between two branches of an HSS K-Connection. This essential study is encapsulated in the article “Rectangular HSS K-Connections with Zero Gap,” with comprehensive research reports noted in the ‘Reference’ section of the corresponding STI article.