Steel Coped Beam with Functionally Graded Material for Offshore Topside: Numerical Investigations

Abstract

The use of rolled steel sections is typical in offshore topside, while recent developments are focused on coped sections to accommodate service lines and fire hydrants. Coped beams are better alternatives without compromising the load-bearing capacity and shear strength. On the topside, the use of coped beams is helpful in creating a more orderly, safe, and undisturbed workspace for laying service mains and fire hydrants; otherwise, they pose a general threat to the topside functional safety. Coped beam replaces the stack of service mains without compromising on the strength requirements of the web. Enhanced safety and improved aesthetics of the topside design are additional advantages. The present study investigates a coped beam with functionally graded material (FGM) to accommodate the services mains in a safer mode without losing its strength; corrosion resistance is also investigated as an additional requirement for any leak occurring from the mains. A coped beam of FGM and X52 steel is investigated under conventional loads and compared for their strength and serviceability requirements. Parameters such as cope length and depth are varied as per the design requirements. FGM coped beams showed higher load-carrying capacity even under the larger coped sections. Under deeper web sections, the cope depth and length have a significant impact on the buckling and load-carrying capacity. For all the chosen coped sections, FGM beams registered a significant reduction in buckling stress compared to X52 steel beams in the coped region, indicating the former is a better candidate for such applications.