Inelastic beam buckling experiments

Abstract

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Lateral–torsional buckling assessment of steel beams through a stiffness reduction method

“…Since this study focuses on the LTB strengths of steel beams, the experiments carried out by Dux and Kitipornchai [26] to investigate out-of-plane instability effects in steel beams of different lengths and subjected to a variety of moment gradient shapes, were chosen to validate the finite element models. In the experiments, the specimens, made up of UB 254x146 universal beam sections, were subjected to point loads along the span, while torsional and lateral restraints were provided at the points of load application.…”

“…In the experiments, the specimens, made up of UB 254x146 universal beam sections, were subjected to point loads along the span, while torsional and lateral restraints were provided at the points of load application. The material properties and cross-section dimensions reported by [26] for each specimen were used within the finite element models. Moreover, the measured values of geometrical imperfections (lateral bow and initial twist) provided by [26] were incorporated into the finite element models assuming them as a half-sine wave in shape for each laterally unrestrained span.…”

Research plan for the study of seismic behavior and design of deep, slender wide flange structural steel beam-column members

“…Initial out-of-straightness is normally expressed as a fraction of the length, L, of the member (about L/l000). Dux and Kitipornchai (1981) and Essa and Kennedy (1993) demonstrated that most hot-rolled wide flange sections tend to have initial out-of-straightness close to maximum permissible tolerances. Information on welded build-up shapes can be found in Alpsten and Tall, 1970;McFalls and Tall, 1970;Alpsten, 1972;Brozzetti et al, 1970b;and Bjorhovde et al, 1972) but is not discussed here.…”

Buckling Approximations for Inelastic Beams

“…are plotted with theoretical capacities (14) and experimental results (3,6) in Figure 5. Several buckling formulae which approximate the theoretical capacity curves of Reference (14) have been proposed.…”

“…The analysis method for determinate inelastic laterally continuous beams is an extension of the elastic beam analysis previously proposed by the authors (4,6). The critical segment is assumed to hav e reduced uniform rigidities, the change being determined by a stiffness modification factor.…”