Stability design of columns with intermediate gravity loads
Link to publisher version (URL)
This paper describes an accurate and economical procedure for determining the flexural effective length of a column subjected to concentrated gravity loads within its unsupported length, for applications in the 2D second-order elastic analysis based design procedure. The presented buckling model has "notional" horizontal restraints where equivalent horizontal forces have been applied, and can be readily programmed into a structural analysis/design software. The performance of the procedure is compared against that using an effective length factor equal to unity and the buckling model described in the European drive-in rack design code. Twenty columns having various end restraint conditions subjected to concentrated gravity loads within their unsupported lengths are analysed to demonstrate the merits of the present procedure. It is demonstrated that, in most of the cases analysed, the present procedure leads to more liberal column capacities compared to the use of the unity effective length factor or the buckling model of the European drive-in rack design code. On average, the more liberal capacities are significantly closer to the ultimate loads determined through second-order plastic-zone analysis.