OPTIMUM DESIGN OF LATTICE PORTAL FRAMES

Abstract

Lattice portal frame structures fabricated using hot rolled angle sections for corner leg members laced together are often very economical systems for industrial structures. There is considerable flexibility in the design of such structures in terms of the spacings between and the unsupported lengths of corner leg members, besides the areas of the different elements of the frame. The minimum weight design of these frames is a nonlinear optimization problem which has been solved by using Rosen's gradient projection method. A computer program OPTFRAM, developed for the minimum weight design of lattice portal frames used in industrial structures, is described. This paper also presents the results of a parametric study carried out using the (OPTFRAM) computer program. Regression equations obtained from this study arc presented for use in day to day design.

KEYWORDS:

• structural design
• lattices
• portal frames
• optimization
• industrial structures