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RESEARCH Selected Research Projects
NSF CAREER Award "CAREER: Comprehensive Research on Cold-Formed Steel Sheathed Shear Walls: Special Detailing, Design, and Innovation" PI: Dr. Cheng Yu Sponsor: National Science Foundation. NSF Program: CMMI - HAZARD MIT & STRUCTURAL ENG Period: September 2010 - August 2015 Award Number: 0955189 Abstract:
The research
objective of this Faculty Early Career Development (CAREER) project is to
close the knowledge gaps about the behavior of cold-formed steel lateral
force resisting systems that use shear walls sheathed with steel or wood
panels. The study includes three major tasks: 1) Configuring a unique
testing method designed to investigate the performance of cold-formed steel
shear walls under realistic loading conditions to provide reliable
experimental data to evaluate the current code prescribed shear wall
strengths. 2) Based on the experimental data, establish accurate analytical
models to predict the shear strength of cold-formed steel shear walls made
with different sheathing materials and to provide design equations based on
the principles of mechanics and mathematical models. 3) Develop advanced
designs of high-performance shear wall systems with enhanced ductility and
strength for low cost building constructions in seismic and strong wind
zones.
Research details and progress reports are provided in the NSF-CAREER site. Link to the NSF-CAREER project website.
Performance and Detailing of Cold-Formed Steel Framed Shear Walls using Corrugated Steel Sheathing PI: Dr. Cheng Yu Sponsor: American Iron and Steel Institute, National Science Foundation (through CAREER award) Period: 2008 - Present Abstract: This is an ongoing project aimed at investigating the appropriate framing and sheathing details for cold-formed steel framed shear wall using corrugated steel sheathing. Initial study shows that the corrugated steel sheathing offers significantly improved stiffness and strength compared to flat sheet steel sheathing. The research continues to focus on ductility issues and seismic performance of those unconventional cold-formed steel shear walls.
Comparison of Cold-Formed Steel Framed Shear Wall using Different Sheathing
Steel Sheet Sheathing Options for Cold-formed Steel Framed Shear Walls Assemblies Providing Shear Resistance - Phase I and II PI: Dr. Cheng Yu Sponsor: American Iron and Steel Institute, Steel Stud Manufacturers Association Period: 2007 - 2009 Abstract: Phase I - In cold-formed steel construction, stud walls covered with steel sheet sheathing is an available option to resist lateral loads such as those caused by wind and earthquakes. The current American Iron and Steel Institute (AISI) Standard for Cold-Formed Steel Framing - Lateral Design 2004 Edition provides nominal shear strength for a limited range of steel sheet sheathed shear wall configurations. This research project was developed to add values for 0.030-in. and 0.033-in. steel sheet sheathed shear walls with 2:1 and 4:1 aspect ratios and 0.027-in. sheet steel shear walls with 2:1 aspect ratio and 6-in., 4-in., 3-in., and 2-in. fastener spacing at panel edges. For all specimen configurations, the steel sheet sheathing was installed on one face of the wall. The test program consisted of two series of shear wall tests. The first series focused on determining the nominal shear strength for wind loads for which monotonic tests in accordance with ASTM E564 standard were performed. The second series of tests addressed the nominal shear strength for seismic loads for which the reversed cyclic tests using CUREE protocol were conducted. The research was sponsored by AISI and SSMA, and was performed at University of North Texas.
Phase II - Monotonic and cyclic tests on cold-formed steel shear walls sheathed with steel sheets on one side were conducted to (1) verify the published nominal shear strength for 18-mil and 27-mil steel sheets; and (2) investigate the behavior of 6-ft. wide shear walls with multiple steel sheets. This project is the continuation of a completed project titled Steel Sheet Sheathing Options for Cold-Formed Steel Framed Shear Wall Assemblies Providing Shear Resistance by Yu (2007). This Phase 2 project confirms the discrepancy in the published nominal strength of 27-mil sheets discovered by the Phase 1 project, and proposes new values. The project also finds disagreement on the nominal strength of 18-mil sheets for seismic design, which requires further research. For the 6-ft. wide shear walls, this project indentifies special seismic detailing to prevent potential damage on studs while improving the strength and ductility of the shear walls. This report provides detailed information on the test setup, test results, and analyses.
Phase 1 report available on AISI website. link to phase 1 report. Phase 2 report available on AISI website. link to phase 2 report.
Cold-formed Steel Bolted Connections using Oversized Holes without Washers - Phases I and II PI: Dr. Cheng Yu Sponsor: American Iron and Steel Institute, Metal Building Manufacturers Association Period: 2007 - 2009 Abstract: In cold-formed steel (CFS) construction, bolted connections without washers for either oversized or slotted holes may significantly expedite the installation process and lower the cost. The North American Specification for the Design of Cold-Formed Steel Structural Members requires washers to be installed in bolted connections with oversized or slotted holes. A two phase research project sponsored by American Iron and Steel Institute was recently completed at the University of North Texas (UNT) that investigated the performance and strength of bolted CFS connections with oversized and slotted holes without using washers. The bolted CFS connections were studied in a broader respect in terms of the failure mechanism, the material thickness, and the hole configurations. Combined with Phase 1 results, the Phase 2 report gives a comprehensive evaluation of the behavior and strength of bolted CFS connections with oversized and slotted holes without using washers. Revisions to the existing AISI North American Specification requirements for bolted connections are proposed to account for the reduction in the connection strength caused by the oversized and slotted hole configurations without washers.
Phase 1 report available on AISI website. link to Phase 1 report. Phase 2 report available on AISI website. link to Phase 2 report.
Evaluation of Stiffback System for Monolithic Placement of Ecospan Joist on Insulated Concrete Form (ICF) Walls PI: Dr. Cheng Yu Sponsor: Nucor R & D Period: 2008 - 2009 Abstract: The objective of this project is to experimentally investigate the axial load bearing capacity and deflection of the cold-formed stiffback under a dead load on scaffold, a wind load, and a combination of two loads. Two stiffback thicknesses were investigated: 16 gauge and 14 gauge. The test program was focused on the stiffback with full height. However smaller height of stiffbck was also studied in this test program.
Behavior and Performance of Steel Moment Frame under Cyclic Loading PI: Dr. Cheng Yu Sponsor: BORM Associates. Period: 2007 - 2008 Abstract:
The research objective of this
project is to investigate the structural performance of BORM standard moment
frame under cyclic loadings (CUREE loading protocol) by the finite element
method. The research results support the development of a full scale cyclic
test program on those specially designed steel moment frame.
Complete List of Funded Research Projects External 20. Principal Investigator, Strength of Stud-to-Track Connections, Nuconsteel Corp., June 2010 - July 2010. 19. Principal Investigator, CAREER: Comprehensive Research on Cold-Formed Steel Sheathed Shear Walls: Special Detailing, Design, and Innovation, National Science Foundation, 2010 - 2015, $433,610. ($400,010 NSF, $33,600 UNT). 18. Principal Investigator, Compression Strength of Truss Chord Members, Nuconsteel Corp., April 2010 - June 2010. 17. Principal Investigator, Testing and Analysis of Cold-Formed Steel Structures, Nuconsteel Corp., June 2009 - August 2009. 16. Principal Investigator, Eccentrically Loaded Cold-Formed Steel Wall Stud Walls, Nucor Corporation, August 2008 - August 2009. 15. Principal Investigator, Evaluation of Stiffback for Monolithic Placement of Monolithic Placement of Ecospan Joist on ICF, Nucor Corporation, August 2008 - August 2009. 14. Principal Investigator, Shear Resistance of Cold-Formed Steel Stud Walls with Wider Range of Options in Steel Sheathing - Phase Two, American Iron and Steel Institute, August 2008 - December 2008. 13. Principal Investigator, Testing and Analysis of Cold-Formed Steel Connections with Bolts in Oversize Holes or Short Slots without Washers - Phase 2, American Iron and Steel Institute, October 2008 - September 2009. 12. Principal Investigator, Testing and Analysis of Cold-Formed Steel Structures, Nuconsteel Corp., June 2008 - May 2009. 11. Principal Investigator, Shear Resistance of Cold-formed Steel Framed Shear Wall Assemblies for Mid-rise Construction, Worthington Industries, February 2008 - July 2008. 10. Principal Investigator, Finite Element Analysis on Special Braced Frame, BORM Associates, Inc, June 2007 - December 2007. 9. Principal Investigator, Testing and Analysis of Cold-Formed Steel Structures, Nuconsteel Corp., June 2007 - May 2008. 8. Principal Investigator, Finite Element Analysis on BORM Moment Frame, BORM Associates, Inc, April 2007 - May 2007. 7. Principal Investigator, Testing and Analysis of Cold-Formed Steel Connections with Bolts in Oversize Holes or Short Slots without Washers, American Iron and Steel Institute, April 2007 - August 2008. 6. Principal Investigator, Shear Resistance of Cold-Formed Steel Stud Walls with Wider Range of Options in Steel Sheathing, American Iron and Steel Institute, January 2007 - April 2007. 5. Principal Investigator, Testing and Analysis of Cold-Formed Steel Structures, Nuconsteel Corp., June 2006 - May 2007. 4. Co-Principal Investigator, Cold-Formed Steel Structures Analysis, Nuconsteel Corp., June 2005 - May 2006 (PI: Dr. Bill Grubbs).
Internal 3. Principal Investigator, Probabilistic Structural Safety Assessment of Bolted Connections for Building Exposed to Seismic and Wind Hazards, UAEM-UNT Research Seed Funding Program, University of North Texas, January 2010 - December 2010. 2. Principal Investigator, Towards Design Provisions for Cold-Formed Steel Beams with Edge Stiffened Perforations. Faculty Research Grant, University of North Texas, September 2006 - August 2007. 1. Principal Investigator, Effective Width Method Based Cold-Formed Steel Design for Distortional Buckling, Faculty Research Grant, University of North Texas, September 2005 - May 2006.
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Last updated 11/26/10