Projects : Task Order 32
Seismic Behavior and Design of Deep, Slender Wide-Flange Structural Steel Beam-Column Members: Phase 2 Experimental Evaluation
SUMMARY
The primary objective of this task order is to develop and implement a testing program to study the behavior of plastic hinges in idealized deep, slender wide-flange structural steel beam-columns undergoing significant cyclic loading. As specified in the Statement of Work (SOW) that accompanied the request for proposal, testing I-2 shall be conducted on beam-column sections that are not influenced by variations in member-end boundary conditions, which are idealized as rotationally and torsionally restrained or free.
The SOW also provides the following constraints and caveats to assist in focusing the effort into the specific area of deep beam-columns:
1. Sections nominally deeper than a W16, but no deeper than a W27, with a range of flange and web slenderness ratios shall be selected to investigate the range and progression of damage states, based on the potential of local buckling versus global member failure. Sections shall be classified as Highly Ductile or Moderately Ductile in accordance with ANSI/AISC 341.
2. Members controlled by different axial or flexural limit states shall be investigated to study differences in damage progression between these limits. All members selected shall be susceptible to a lateral-torsional buckling failure mode under uniform bending per
ANSI/AISC 360.
3. Beam-columns shall be tested with idealized boundary conditions, which are rotationally and torsionally restrained or free. In all approximately 20 beam-column tests shall be conducted under this task order.
4. The loading protocols to be defined as part of this task order shall include both monotonic and cyclic loading. Sufficient axial load ratios (force / yield strength) shall be included in order to adequately capture cross-section response variations (e.g., 0.1, 0.3, 0.5, 0.75, 0.9 times the nominal axial yield strength).
5. Structural steel shall conform to A992 Grade 50 as defined by ASTM A992/A992M, Standard Specification for Structural Steel Shapes.
6. The experimental work shall be complemented with analytical studies to investigate the mechanisms identified by the tests, as well as to expand the results to a larger population of section sizes than just those tested.
Because this work is a direct result of the work to develop the NIST GCR 11-917-13 Research Plan, members of the original project team are proposed as members of the Project Technical Committee, subject to confirmation by the Joint Venture Program Committee and approval by NIST:
• James O. Malley (Project Director), Degenkolb Engineers, San Francisco, California (structural engineering practitioner licensed in the United States with extensive experience in the seismic design of structural steel buildings and model code development);
• Charles Carter, American Institute of Steel Construction, Chicago, Illinois (AISC representative);
• Jerome F. Hajjar, Northeastern University, Boston, Massachusetts (researcher with extensive experience in the testing and analysis of structural steel components)
• Dimitrios Lignos, McGill University, Montreal, Quebec, Canada (researcher with extensive experience in analytical investigations of structural steel components)
• Charles Roeder, University of Washington, Seattle, Washington (researcher with extensive experience in experimental investigations of structural steel components); and
• Mark Saunders, Rutherford & Chekene, San Francisco, California (structural engineering practitioner licensed in the United States with extensive experience in the seismic design of steel frame structures).
