Effect of web stiffeners on the lateral distortional buckling of channel section with hollow flanges

Abstract

Hollow Flange Channels (HFC) have been known for their higher capacity when compared to open flange C-sections. On the other hand, the small stiffness of HFC slender web compared to their flanges limits the bending capacity to the lateral distortional buckling (LDB) strength. Welding web stiffeners can limit the web distortion and enhance the bending capacity. This paper investigates how to alleviate LDB capacity of HFCs using transverse web stiffeners. Stiffener’s spacing, depth and thickness are the parameters, modeled with different beam lengths. It is found that using the right spacing and depth of stiffeners can greatly increase the HFC capacity. Adding full depth stiffener to 4000 mm span increases the capacity by 32%. However, this percentage decreases for longer spans with partial depth stiffeners. Increasing the stiffener thickness have been found insignificant in enhancing the performance. A new formula is proposed to predict the bending capacity of stiffened HFC.