Line Girder Analysis for Skewed Straight Steel I-Girder Bridges

The Florida Department of Transportation currently requires a refined method of analysis for skewed straight steel I-girder bridges with a skew index, I_s, greater than 0.2 and less than or equal to 0.6. Researchers are improving our understanding of how skewed straight steel I-girders with skew indices up to and slightly larger than 0.3 behave, and to determine how much line girder analysis (LGA) applies to such bridges. The research included comparative parametric 3D finite element analysis and LGA studies of 26 bridges. The results showed that routine LGA models using equal distribution of dead loads to the girders and established AASHTO live load distribution factors provide a fast and sufficient solution for skewed straight steel I-girder bridges with I_s up to 0.45 and skew angle, θ, up to 50 degrees, within certain qualifications. The speakers will present this research and also cover recommendations to improve design estimates of girder flange lateral bending stresses as well as cross-frame and diaphragm forces for designs using LGA.

This course is based on a past AISC Live Webinar.

 

Videos

Line Girder Analysis for Skewed Straight Steel I-Girder Bridges