ASDIP Steel – Steel Column Design

About ASDIP Steel:Overview | Benefits | Features | DocumentationModules:Steel Base Plate Design | Steel Column Design | Steel & Composite Beam Design

Columns are structural members that mostly work in compression and bending, and only very short columns can be axially loaded to their yield stress. Often buckling, or sudden bending as a result of instability, occurs prior to developing the full material strength.

This module performs the design of a steel column subjected to axial load and bending moments about its two principal axes. The program is based on the AISC ASD/LRFD methodology and checks the axial, bending, and combined stresses according to the AISC 360-10 Specifications (14th Ed. Manual). Either service or factored loads may be specified.

Two types of procedures may be followed in order to calculate the required strength and the design requirements, depending on the source of the loads entered as input data:
a) Second-Order Analysis, which considers the P-Delta and P-delta effects. No further load magnification is required.
b) Amplified First-Order Analysis. In this case the program will calculate the amplified moments based on the information provided, to account for the slenderness effects.

Input Data

The input data required by the program includes the material properties and member geometry, as well as applied loads. In addition, the effective length K-factors in both X and Y directions are required. Use the buit-in properties database if necessary.

Example

As an example, consider a 30′-0″ W10x54 steel column subjected to a factored axial compression of 100 k and bending moments of 60 and 20 k-ft around the strong and weak axis respectively. Effective length factors are Kx = 1.0 and Ky = 0.7. Loads are the result of a second-order analysis.

Output

The design process is simple with ASDIP Steel. First, enter your input data using the rich set of controls. Then use the Design Manager to find all the steel sections that meet the design criteria. Sort the table if you wish, either by weight or by design ratio. Finally, when you select one of these winner sections, the corresponding properties are transferred automatically to your calculations.

In this example, the proposed column size is adequate since the design ratios for compression, flexure and combined forces are 0.29, 0.29 and 0.69 respectively. Further optimization is possible since the controlling ratio is 0.69 and there is room to select a lighter section.