Numerical Study for Strengthening Hexagonal Castellated Steel Beams Using Hexagonal Ring Stiffeners

This paper investigates numerically how the castellated steel beams are affected by the addition of hexagonal stiffeners around hexagonal web openings. Increasing the CSBs' load-bearing capacity and improving their overall structural behavior are the main objectives of this strengthening technique. Although there are different failure modes as a result of castellation, the main emphasis of this study is web post-buckling. Using ABAQUS software, a 3D finite element model is created to analyze the beam's behavior. The model's accuracy was validated by comparing its results with those from previous experimental studies. Failure loads, failure modes, and load-deflection curves of CSBs are investigated in this study. An extensive parametric study is conducted on simply supported castellated steel beams subjected to a concentrated load in mid-span. The study investigates the effects of hexagonal stiffener properties, such as stiffener thickness (ts) and stiffener width (bs), on the load capacity and failure modes. According to the parametric analysis, adding hexagonal stiffeners to CSBs from both sides strengthens them and improves their load-bearing capacity while also reducing web post-buckling. The ultimate load increases as the stiffener thickness (ts) is increased from 4 mm to 10 mm. In contrast, increasing the stiffener width (bs) from 20 mm to 40 mm enhances the ultimate load, but to a lesser extent.