Stability of a laterally unsupported chord

Abstract

The purpose of this article is to introduce a method to determine the buckling length of a laterally unsupported chord. In the paper, a laterally unsupported chord indicates to an inner chord of a lattice column or a bottom chord of a truss. In these cases, a separated buckling restraint system is traditionally used to reduce an out-of-plane buckling length. Although the inner or bottom chord is without buckling restraint, the buckling length can significantly be decreased, even up to 0,3L...0,4L where L is the total length of the chord. This is based on the fact, that there is a lot of capacity when a truss/a lattice column is considered as an entirety, taking into account the bending and rotational stiffness of brace members and torsional stiffness of tension/stabilizing chord.