ANALYTICAL MODEL FOR THE EVALUATION OF TORSIONAL CONNECTION RESTRAINTS OF STEEL BEAMS IN BENDING

Salah, Amara; Ali, Zaidi; Mohamed, Lamara; Jean Pierre, Jaspart

Revue des sciences et sciences de l’ingénieur
Volume 2, Numéro 1, Pages 27-35
2012-12-01

Analytical Model For The Evaluation Of Torsional Connection Restraints Of Steel Beams In Bending

Authors : Salah Amara . Ali Zaidi . Mohamed Lamara . Jean Pierre Jaspart .

Abstract

One of the most commonly employed general formulae to estimate the elastic critical moment Mcr is the so-called 3-factor formula. This formula is applicable only for extreme end support conditions such as fixed or pinned supports. However, some particular cases met in practice are currently not covered, most notably the case of beams with partial end restraints against minor bending axis, and partial end restraints against twisting and fin-plate connections are a good example. The scope of the present work is to attempt to fill in one of the insufficiencies identified in the so-called 3-factor formula used by the Eurocode 3, by proposing a mathematical model for computing the value of the connection torsional restraint coefficient. In order to take into account the real restraint conditions of the supports, the proposed coefficient will be introduced in the formulae of the elastic critical moment Mcr given in the Eurocode 3. A comparison between the elastic critical moments for various beam cross-sections, lengths, loading conditions and various end restraints, obtained from the finite elements software LTBeam, and those derived from EC3 ENV formulae, in which the proposed coefficient is introduced, confirms the reliability of this coefficient that models satisfactorily the end support conditions.