to study and make recommendations concerning the utilization of high-strength steel reinforcing bars in concrete structures subjected to earthquake ground motion. This work grew out of the ATC-57 report, The Missing Piece: Improving Seismic Design and Construction Practices (ATC, 2003), which defines a roadmap for the NIST problem-focused research and development program in earthquake engineering. The ATC-57 report recommended that NIST examine new technologies that can improve construction productivity, such as high-strength reinforcement. The NEHRP Consultants Joint Venture is indebted to the leadership of Dominic J.

The objective of this task was to develop a comprehensive long-range plan to research the seismic behavior of deep, slender wide flange structural steel beamcolumns in steel frames. Development of the plan included the investigation of available information on beam-column member and connection behavior in the literature, and considered the differences and interrelationships between member, subassemblage, and system performance. The resulting plan includes a summary of tasks for conducting both experimental and analytical research, and is intended to be the first step in the development of national consensus guidelines for designing and assessing the seismic performance of deep, slender wide-flange beam-columns in steel frame systems.The NEHRP Consultants Joint Venture is indebted to the leadership of Jim Malley, Project Director, and to the members of the Project Technical Committee, consisting of Charlie Carter, Jerry Hajjar, Dimitrios Lignos, Charles Roeder, and Mark Saunders for their contributions in developing this report and the resulting recommendations. The NEHRP Consultants Joint Venture also gratefully acknowledges Jack Hayes (NEHRP Director), Steve McCabe (NEHRP Deputy Director), Jay Harris (NIST Project Manager), Mike Mahoney (FEMA), and Helmut Krawinkler (FEMA Technical Monitor) for their input and guidance in the preparation of this report, Ayse Hortacsu for ATC project management, and Peter N. Mork for ATC report production services. Jon A. Heintz Program ManagerGCR 11-917-13 List of Tables Executive SummaryCurrent practice in modern steel frame design frequently concentrates seismic resistance into a few frames or a few bays within planar frames. In moment resisting frames, this practice results in column designs that are dominated by a combination of axial force and bending due to lateral deformation, rather than just axial force alone. Due to their increased in-plane flexural stiffness, deeper column sections are generally selected to satisfy drift criteria and to balance relative stiffness with deep beam sections. Columns that are generally stocky, in terms of both member stability and cross-sectional compactness requirements, are expected to perform well under seismic loading. Deeper, more slender columns, however, are more vulnerable to weak-axis and local buckling failure modes, and these sections must be checked against the potential for in-plane and out-of-plane instability under combined axial load and bending moment.The term deep refers to member depths that are nominally greater than 16 inches (i.e., W16 sections and larger). The term slender refers to members that are sensitive to instability or have cross-sectional elements with width-to-thickness ratios approaching the seismic compactness limits for highly ductile members. An area of critical need identified by the American Institute of Steel Construction (AISC) is the seismic performance of deep, slender, wide flange structural steel beam-column members when subjected to a range of axial loads. Research on the stability of th...