In curved I-girder systems, stability is mainly provided by interconnecting cross-frames or diaphragms. These members act as primary load carrying component thus proper design and analysis must be made. This study proposes improvement on the existing cross-frame spacing limit for horizontally curved girder systems utilizing buckling capacities. Eigenvalue analysis was conducted using the finite element program, ABAQUS. Maximum cross-frames spacing (Smax) was computed with varying degree of curvature, flange width-to-depth ratio ( ) and span length-to-depth ratio (L/d). Models were then generated and their buckling modes and critical buckling capacity ratios were obtained. Lastly, a suggestion was developed based on the results of the finite element analysis to provide a better guide on the design of cross-frame spacing limit. The suggested limit was then compared to the existing cross-frame limit to verify the improvement on the cross-frame spacing.

This parametric study investigates the effect of significant parameters on the elastic global lateral torsional buckling capacity of horizontally curved twin I-girder systems. Included are the effect of curvature and the effect of girder spacing. Twin I-girder systems analyzed in this study are those which are interconnected by intermediate cross frames and are subjected to uniform moment. The finite element analysis software, ABAQUS, is used to model the horizontally curved twin I-girder system and conduct the buckling analysis. To see the significant effect of curvature and girder spacing, the results from the finite element analysis of horizontally curved twin I-girder systems are compared to the results of a closed form solution for straight twin I-girder systems. The findings of this parametric study will be shown using illustrative figures and tabulated data and conclusions are made.