Parametric Analysis of the Flexural Bearing Capacity and Ductility of Hybrid Steel I-Section Beams

Considering the advantages of hybrid steel I-section beams in reducing engineering costs and fully utilizing the mechanical properties of steel, and the lack of research on their ductility, hybrid steel I-section beams were tested to analyze the effects of the plate width-thickness ratio and steel strength matching on the flexural bearing capacity and ductility. The steel strength matching of the hybrid steel I-section beam with a high steel strength utilization rate and good ductility was related closely to the section size. Additionally, a parametric analysis based on the finite- element method was performed for further study. The steel strength ratio phi of the web to the flange with the best ductility was less than 1, and phi decreased with an increase in flange steel strength. The steel strength utilization rate and ductility decreased with an increase in phi. Based on the parametric analysis results, the optimal range of phi in hybrid-steel I-section beams with flange steel strength of 460-690 MPa was 0.56-1. The plate width-thickness ratio limit of the ductile section decreased with the decrease of phi. Considering the plate interaction and steel strength matching, a sectional ductility design method is proposed that is more applicable to hybrid steel I-section beams than existing methods.