Flexural buckling of laced column with crosswise lattice

Solving the flexural buckling problem of a laced column as a statically indeterminate system is reduced to the two-point boundary value problem for a difference equation system that comprises recurrence relations between the displacements and the force parameters of column cross-sections passing through the lattice joints. The critical force for a column with any degree of static indeterminacy is determined as the smallest eigenvalue of the fourth-order system of linear algebraic equations. The recurrence relations that have been established for the torsional buckling in a preceding study by the author are extended to the case of flexural buckling of a laced column with a crosswise lattice, owing to the static-geometric analogy between the two kinds of buckling. The obtained deflection mode shapes show that the loss of stability of the laced column occurs as a result of the local buckling of column chords and disprove a concept of the sine-shaped deflection mode shape which is basic in design manuals for steel-laced columns (Engesser's assumption). Columns with a very rigid lattice can lose stability, so that joint cross-sections are not displaced, and the chord panels are buckled as isolated simply supported bars. For columns with identical chords, the critical force is a function of the number of panels and the special lattice rigidity parameter of the column. The plots of this function for a series of columns with a varied number of panels may be validly applied in designing steel-laced columns.


  • English

Media Info

Subject/Index Terms

Filing Info

  • Accession Number: 01109610
  • Record Type: Publication
  • Source Agency: Transport Research Laboratory
  • Files: ITRD
  • Created Date: Aug 25 2008 8:48AM