Stability of Trusses: Direct Analysis Method Compared to Experimental Results

The direct analysis method is applicable to all types of framed structures, and therefore has an advantage over other, more limited, stability analysis methods. Research studying stability of full scale trusses subjected to multiple bracing scenarios and loadings has been conducted at the University of Colorado Denver. The first part of the research was developing a 3D structural analysis model using a second order direct analysis to predict a critical buckling load, compared to results of stability experiments of full scale bar joists. The comparisons were used to validate the direct analysis method applied to the models. The bar joists used in the stability experiments inherently have imperfections, while notional loads were used in the computer modeling to represent geometric imperfections. Results from the full scale bar joists tests were shown to validate computer modeling direct analysis results when appropriate initial conditions were applied.