NEHRP Clearinghouse

Title
Lateral Buckling of Short I-Beams Under Cyclic Loading.
File
PB90213653.pdf
Author(s)
Hjelmstad, K. D.; Lee, S.
Source
National Science Foundation, Washington, DC.; American Inst. of Steel Construction, Chicago, IL., April 1990, 154 p.
Identifying Number(s)
['STRUCTURAL RESEARCH SER-549', 'UILU-ENG-90-2001']
Abstract
The report concerns the inelastic lateral buckling and post-buckling behavior of short I-beams subjected to cyclically reversing loads. The eccentrically braced frame, used in the earthquake resistant design of building structures, provides an application in which lateral buckling of short I-beams under cyclic loading is relevant. The authors main purpose is to establish some benchmarks with which to assess the consequences of lateral buckling of active link beams in eccentrically braced frames. A geometrically nonlinear beam model, capable of analyzing lateral buckling of short I-beams under cyclic loading, is formulated in terms of stress components. The novel kinematic model includes a geometrically exact representation of the primary torsional warping as well as secondary warping due to torsion and transverse shear. A new cyclic plasticity model, incorporating many of the most compelling features of existing phenomenological models, is developed and implemented with a consistent return mapping algorithm. The new model represents cyclic metal plasticity well and is suitable for large-scale computation. The experimental research program comprised five tests of propped cantilever beams subjected to a cyclically reversing point load acting near the fixed end. The experiments include both braced and unbraced beams subjected to similar loading histories. The effects of constitutive parameters, residual stresses, load placement, geometric imperfections, flexible boundary conditions, and lateral bracing are examined.
Keywords
; Structural engineering; Beams (Supports); Deformation; Experimental data; Test facilities; Mathematical models; I beams; Stresses; Buckling; Cyclic loads; Stress cycle; Loads (Forces); Structural members; Structural analysis