Finite Element analysis of the effects of frame deformation on welded gusset plates

Author

Daniel Paul Strauss, Southern Illinois University CarbondaleFollow

Date of Award

5-1-2010

Degree Name

Master of Science

Department

Civil Engineering

First Advisor

Hsiao, J. Kent

Abstract

The traditional design method of gusset plates neglects the frame deformation's effect, which could lead to under designing the gusset plate. The traditional design method only considers the stress caused by the bracing member in tension, which creates tension and shear stresses in the gusset plate, however, the deformation of the column and beam connected to the gusset plate introduce compressive stresses, potentially increasing the stress in the gusset plate. The following factors are studied using finite element method: (a) the relative stiffness between the beam, the column and the bracing element, and (b) the configuration of the gusset plate. Two gusset plate configurations and two beam and column cross sections were used to compare the results. To determine the increase caused by the frame deformation two approaches were used; approach I ignores frame deformation while approach II takes into consideration the effects of frame deformation. This study concludes that factor b, the configuration of the gusset plate, has the greatest impact on the increase of stress at the end of the weld. Additionally, factor a, the relative stiffness between the beam to bracing element and column to bracing element, has a slightly less significant impact on the gusset plate stress than the configuration of the gusset plate. Both factors need to be studied more to determine their maximum potential increase of the stress, as well as another factor (c) the angle between the center line of the bracing element and the center line of the column, which would change the relative stiffness between the beam and column.