Elastic buckling and ultimate load of portal frames

Abstract EN

Existing portal frames were often built for industry using an extensive amount of material.

The buckling and the ultimate loads are thus crucial values often determined assuming concentrated loads on top of the columns.

Usually, the frames carry distributed loads that always create primary moments, in addition to compressive forces transferred from the supports to the beams, which may reduce the buckling load.

This paper investigates the accurate buckling and the ultimate load behavior of portal frames.

The analysis uses different loading patterns in addition to different methods of analysis, and also takes into consideration big deformations.

The investigations use both analytical, 2-D and a 3-D Finite Element Analysis (FEA) to ensure the validity and accuracy of the results.

An approximate method in addition to the accurate numerical method is given.

The limitations, accuracy, and validity of the proposed method are found, and design precautions and recommendations are also given.