Theoretical prediction of buckling deflection for I-shaped steel beams reinforced with bamboo scrimber stiffeners (BSSs)

In response to the buckling instability problem of I-shaped steel beams, a new method of using bamboo scrimber stiffeners (BSSs) to constrain the lateral-torsional buckling (LTB) of the steel beam is proposed. This method uses epoxy adhesive to combine BSSs and pure I-shaped steel beam (PIS) together to work synergistically. 12 full-scale beam specimens were tested and a series of refined finite element models (FEMs) corresponding to PIS and I-shaped steel beams reinforced with BSSs was established to investigate the Mises stress distribution in unstable regions that are difficult to obtain in experiments, which will contribute to buckling analysis. It was found that as the spacing between BSSs decreased, the moment enhancement in the critical buckling point was relatively small, ranging from 5.84 % to 11.94 %, as compared to PIS. However, the critical buckling deflection was significantly improved, with up to 167.40 % increase compared to PIS. Numerical and experimental results both show that BSSs alter the instability behavior of I-shaped steel beams, shifting rapid LTB failure to a slower lateral torsion of the web plate and localized buckling of compressed flanges between BSSs. To further expand the application scenarios, 17 additional simulation specimens were established to study the reinforcement effect of BSSs with varying lengths and quantities on beams with different clear spans. According to the experimental and numerical results, a critical buckling deflection prediction formula for I-shaped steel beam reinforced with BSSs was derived, which achieved good results and provided theoretical basis for practical engineering applications.