ABSTRACT

Steel sections are generally used in offshore topside, while the recent development focused on expanding the need for production, living, and storage capacity. As a result, a cluster of water mains, fire hydrants, sewage lines, power cables, and telecommunication wires, storage pipelines are found to be on the higher side. In this study, a coped beam is used on the offshore topside with functionally graded materials, and its behavior with deeper web sections is investigated. A novel FE model is proposed to assess the load-carrying capacity and failure pattern of the coped beam. results are compared with the conventional X52 steel in terms of strength and corrosion resistance. It is observed that the FGM coped beam has a higher load-carrying capacity. The cope depth and cope length have a greater influence on the buckling and load-carrying capacity of deeper web sections. A limiting criterion is arrived at to accommodate the pie stack in the coped sections of the web, creating a more clean and undisturbed workspace on the topside without compromising the strength

INTRODUCTION

Offshore topsides are generally used to build steel structures. The offshore topside structures were used for the exploration of oil and natural gas by using drilling derricks. The top side is also used for production, storage, and offloading (Chandrasekaran et al., 2019; Chandrasekaran et al., 2021). Typically, during the design and construction of steel frame structures, the steel beams are fabricated to be compatible with other steel beams. Consequently, coping or slotting is typically necessary for steel beams to fit perfectly, resulting in the term steel coped beam (Yam and Cheng., 1990; Cheng and Yura., 1986). For instance, it is frequently necessary to remove a portion of a flange or web in order to ensure that the secondary beam and main girder fit without conflict or interference. Common types of steel-coped beams include both single- and double-coped beams (Cheng., 1993). As shown in Fig.1 a single-coped beam has either the top or bottom flange coped, whereas a double-coped beam has both the top and bottom flange coped. In recent decades, the mechanical behaviours of coped steel beams, particularly their fatigue and local web buckling strength, have been intensively studied (Gupta et al., 1984; Lam et al., 2000; Cheng and Yura., 1986). In steel beams with end copes, the strength and torsional stiffness are reduced at the coped section, and a high-stress concentration is introduced at the web corner. Lateral torsional buckling, local web buckling, and fatigue cracking are the three most effective and appropriate failures Therefore, the load-carrying capacity of the coped steel beam is significantly less than that of conventional steel beams. (Maljaars et al., 2005; Fang et al., 2017). Different types of reinforcement stiffeners were designed and applied to prevent local buckling of the slender web. It was determined that the design methods for conventional steel beams also apply to coped steel beams strengthened with the appropriate reinforcement stiffeners (Yam et al., 2007). Techniques for reinforcing coped steel beams with horizontal and vertical stiffeners. It was determined that stiffeners could increase the load-carrying capacity of coped steel beams by approximately 125%, and both vertical and horizontal stiffeners were recommended for coped steel beams with greater cope depth (Ibrahim et al., 2020).

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