This is the accepted version of the paper.This version of the publication may differ from the final published version. Abstract. Lateral torsional buckling is a key factor in the design of steel girders. Stability can be enhanced by crossbracing, reducing the effective length and thus increasing the ultimate capacity. U-frames are an option often used to brace the girders, when designing through type of bridges and where overhead bracing is not practical. This paper investigates the effect of the U-frame spacing on the stability of the parallel girders. Eigenvalue buckling analysis was undertaken with four different spacings of the U-frames. Results were extracted from finite element analysis, interpreted and conclusions drawn. Permanent repository link