Effective length factors for the lateral torsional buckling of cantilever beams

Using glass as a primary load-carrying element is becoming more and more popular in architecture. Probably the most used application is the single-span girder, but another important system is the cantilever beam, which is widely used, e.g., as a canopy in front of an entrance. Research on the lateral-torsional buckling behavior of glass beams has been typically performed on single-span girders. As a consequence, the design buckling curves provided in literature are usually too conservative for the widely used case of a cantilever beam, which is also related to the loading situation. Therefore, experimental and numerical investigations have been performed for this special case. Based on the obtained results, design buckling curves have been developed and resulted in being more economical than the curves already given in the literature. Among others, information on the shape and size of the real imperfections, a testing device for cantilever beams, and experimentally and numerically obtained load-deflection curves are additional outcomes of the investigations presented here.

Download Full-text

Lateral torsional buckling of steel twin plate girder systems with torsional braces only

Canadian Journal of Civil Engineering ◽

10.1139/cjce-2015-0170 ◽

2016 ◽

Vol 43 (2) ◽

pp. 182-192 ◽

Cited By ~ 1

Author(s):

Chris Mantha ◽

Xi Chen ◽

Yi Liu

Keyword(s):

Finite Element ◽

Design Procedure ◽

Element Model ◽

Torsional Stiffness ◽

Effective Length ◽

Lateral Torsional Buckling ◽

Torsional Buckling ◽

Finite Element Study ◽

Element Study ◽

Plate Girder

This paper presents results of both an experimental and a finite element study on the lateral torsional buckling behaviour and strength of twin plate girder systems with only discrete torsional braces. Two scaled twin-beam specimens with different arrangements of lateral and torsional braces were tested and results were used to validate the finite element model. The finite element study considered the effect of individual brace member stiffness and the number of braces. Results showed that for twin plate girders braced with only torsional braces, the critical buckling moment has the most significant increase when the number of interior braces increases from two to three. For a given girder section, the increase in the critical moment capacity by increasing the cross-frame member size is minimal. The lateral torsional buckling moment equation as well as the brace force design procedure contained in the Canadian Highway Bridge Design Code were examined. A relationship between the ratio of provided-to-required torsional stiffness and the effective length factor was discussed.

Download Full-text

Effective lengths of laterally continuous, laterally unsupported steel beams

Canadian Journal of Civil Engineering ◽

10.1139/l85-068 ◽

1985 ◽

Vol 12 (3) ◽

pp. 603-616 ◽

Cited By ~ 1

Author(s):

Calvin D. Schmitke ◽

D. J. Laurie Kennedy

Keyword(s):

Bending Moment ◽

Effective Length ◽

Steel Beams ◽

Lateral Torsional Buckling ◽

Limit States ◽

Torsional Buckling ◽

Resistance Factors ◽

New Methods ◽

Fundamental Equations ◽

Effective Length Method

Laterally unsupported steel beams of sufficient length may fail by elastic or inelastic lateral–torsional buckling. The fundamental equations governing elastic lateral–torsional buckling, taking into account such parameters as the shape of the bending moment diagram, the level of application of the load, and the effect of end restraints to lateral movement and to twist, are reviewed. Provisions in the current CSA Standard CAN3-S16.1-M84 are discussed. The methods currently available for dealing with the interactive lateral–torsional buckling of laterally continuous beams are evaluated statistically. Two new methods for considering this interaction, called the iterated effective length method and the equivalent beam method, are presented. A statistical evaluation of these methods shows that they are in reasonable agreement with available test data. Resistance factors for use in limit-states design are developed for the existing methods discussed as well as for the new methods. Key words: beam, bending moment, buckling, effective lengths, elastic, inelastic, lateral–torsional buckling, laterally continuous, steel.

Download Full-text

Design Curve to Use for Lateral Torsional Buckling of Tapered Cantilever Beams

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.274-276.981 ◽

2004 ◽

Vol 274-276 ◽

pp. 981-986 ◽

Cited By ~ 1

Author(s):

Peter Buffel ◽

Guy Lagae ◽

Rudy Van Impe ◽

Wesley Vanlaere ◽

Jan Belis

Keyword(s):

Cantilever Beams ◽

Lateral Torsional Buckling ◽

Torsional Buckling ◽

Design Curve

Download Full-text

BEHAVIOUR OF PARALLEL GIRDERS STABILISED WITH U‐FRAMES

Journal of Civil Engineering and Management ◽

10.3846/jcem.2010.21 ◽

2010 ◽

Vol 16 (2) ◽

pp. 197-202 ◽

Cited By ~ 2

Author(s):

Kuldeep Virdi ◽

Walid Azzi

Keyword(s):

Finite Element Analysis ◽

Finite Element ◽

Buckling Analysis ◽

Effective Length ◽

Ultimate Capacity ◽

Lateral Torsional Buckling ◽

Torsional Buckling ◽

Element Analysis ◽

Key Factor ◽

The Stability

Lateral torsional buckling is a key factor in the design of steel girders. Stability can be enhanced by cross‐bracing, reducing the effective length and thus increasing the ultimate capacity. U‐frames are an option often used to brace the girders, when designing through type of bridges and where overhead bracing is not practical. This paper investigates the effect of the U‐frame spacing on the stability of the parallel girders. Eigenvalue buckling analysis was undertaken with four different spacings of the U‐frames. Results were extracted from finite element analysis, interpreted and conclusions drawn. Santrauka Projektuojant plienines sijas šoninis sukamasis klupumas yra svarbiausias veiksnys. Pastovumas gali būti padidintas skersiniais ryšiais, mažinančiais veikiamaji ilgi ir padidinančiais ribine galia. U‐formiai remai yra dažna priemone sijoms išramstyti, kai projektuojami tiltai, kuriu laikančiosios konstrukcijos yra virš pakloto, o viršutiniai ryšiai yra nepraktiški. Šiame straipsnyje nagrinejamas U‐formiu remu tarpatramio poveikis lygiagrečiuju siju pastovumui. Tikravertis klupumo skaičiavimas buvo atliktas esant keturiems skirtingiems U‐formiu remu tarpatramiams. Aptarti rezultatai, gauti apskaičiavus baigtinius elementus, padarytos išvados.

Download Full-text