Assessing the Load-Carrying Capacity of Composite Castellated Beams by Finite Element Method

The utilization of composite castellated beams in structures is common due to the increased bending strength and stiffness of the beam. However, the presence of openings in castellated beams reduces their shear strength. The increased bending strength allows these beams to be used over longer spans; however, the reduced shear strength makes shear force effects more pronounced in such beams. In this study, a comparative analysis of the behaviors of composite beams with castellated and solid-web has been conducted using finite element method. Nine composite castellated beams and nine solid-web composite beams, both with equal heights and cross-sectional areas, were modeled based on castellated configurations. The AISC Design Guide ۳۱ (DG۳۱) provides a method for calculating the ultimate bending capacity of composite castellated beams but neglects the contribution of the upper T-shaped section of the castellated beam. In this study, the focus is on innovatively comparing the load-carrying capacity of composite castellated beams with the AISC DG۳۱ results, highlighting how finite element analysis reveals higher capacities than those predicted by DG۳۱ by ۱۷% to ۳۱% across specimens. It is observed that the load-carrying capacity of castellated specimens is ۲% to ۵% lower than that of specimens with solid-webs. This difference may increase up to ۲۲% with local failure in the web-post if the first openings of the beam are placed too close to the supports. Notably, the research demonstrates that the web openings in castellated beams have a minor effect on load-carrying capacity, suggesting that despite reduced shear strength, these openings do not significantly impact the overall capacity, particularly when placed thoughtfully in structural design.

کلیدواژه ها:

Composite castellated beam ، Finite element analysis ، Alternating plasticity ، load-carrying capacity ، vierendeel mechanism ، load-displacement diagram