| Skewed bridge supports for steel I-girder bridges, introduce complexities to the behavior of the girder system that can be difficult to accurately model and analyze. In addition there have been some reported shortfalls in the 2D-grid analysis method typically used by engineers to design steel girder bridges with significant skews. Some improvements have been suggested to bridge the gap in the inaccuracies of 2D-grid and 2D-frame analyses. These improvements include overwriting the girder torsional stiffness to include warping effects, overwriting the equivalent beam stiffness of cross-frames using a more accurate method of calculating the stiffness, including locked-in cross-frame forces due to dead load fit detailing, and more accurately calculating flange lateral bending stresses with staggered cross-frame layouts. This thesis examines these improvements, compares different levels of analysis, provides recommendations for these methods of analysis, and explains the behavior of the girder system during erection. |
