NEHRP Clearinghouse
- Title
- Seismic Behavior of Concentrically Braced Steel Frames.
- File
- PB91210898.pdf
- Author(s)
- Khatib, I. F.; Mahin, S. A.; Pister, K. S.
- Source
- National Science Foundation, Washington, DC., January 1988, 238 p.
- Identifying Number(s)
- UCB/EERC-88/01
- Abstract
- Concentrically braced steel frames designed by conventional methods may exhibit several undesirable modes of behavior. Chevron-braced frames have an inelastic cyclic behavior that is often characterized by rapid redistribution of internal forces, a deterioration of strength, a tendency of form soft stories, and fracture due to excessive deformation demand. Parameters having a significant influence on these phenomena are identified. Recommendations are offered related to preferable ranges of brace slenderness, approaches for designing beams, and a simplified capacity design approach for proportioning columns and connections. Optimization techniques are applied to the design of chevron-braced to improve their seismic responce. Further improvements related to changes in structural systems are presented. These include the use of double story X-braced framing, incorporation of a secondary moment resisting frame, and the use of braces in a V configuration. Each of these approaches has advantages in certain circumstances. Each has disadvantages which are examined using results of analytical parametric studies. The basis of a new structural system which incorporates vertical linkage elements in a conventional chevron-braced frame and appears to overcome in an economical and practical way many of the deficiencies of chevron-braced frames is examined and its effectiveness demonstrated.
- Keywords
- ; Steel construction; Framed structures; Seismic waves; Steel structures; Structural vibration; Frames; Dynamic response; Reinforcement (Structural); Earthquake engineering; Energy dissipation; Structural steels; Loads (Forces); Structural members; Structural analysis