ResearchArticle FiniteElement-BasedPerformanceAnalysisofEncasedComposite Columns under Monotonic Axial Compression Load Kefiyalew Zerfu 1 and Regasa Yadeta 2 1 Department of Civil Engineering, Jimma Institute of Technology, Jimma University, Ethiopia 2 Department of Civil Engineering, College of Engineering and Technology, Mettu University, Ethiopia Correspondence should be addressed to Kefyalew Zerfu; kefyalewz@gmail.com Received 13 September 2022; Revised 27 December 2022; Accepted 20 January 2023; Published 27 January 2023 Academic Editor: Ying Qin Copyright © 2023 Kefyalew Zerfu and Regasa Yadeta. Tis is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Tis paper presents the results of an investigation into the performance of fully encased composite columns under monotonic axial load using fnite element simulation. Te damage characteristics and the performance investigation of the specimen were mainly focused on the infuence of the compressive strength of concrete and the size of reinforcement. Te concrete material was modeled using concrete damage plasticity (CDP), which incorporates the hardening and softening behaviors, and the steel was modeled using metal plasticity. Te results obtained from the current study were validated by using previously conducted experimental work and manual calculation based on Eurocode 4. According to the FEA result, damage to the concrete matrix was signifcantly minimized with the increase in the strength of the concrete. By keeping other parameters constant, an increase in longitudinal reinforcement diameter minimizes the equivalent plastic strain both in structural steel and reinforcement bars. Furthermore, the results showed that the numerical simulation fairly validated the analytical solution. 1.Introduction Due to its structural performance, especially in high•rise buildings and seismic•prone areas, composite construction is getting attention globally. Better functional and perfor• mance requirement of structural system is achieved by the utilization of steel•concrete structure. Due to their superior structural performance compared with conventional rein• forced concrete (RC) columns, concrete•encased steel (CES) composite columns are gaining popularity in top•down or basement construction [1–3]. An advantage of composite structure construction is that the structure acquires its strength from the combined resistance of concrete and steel. Steel structures usually have improved ductility, high strength•to•weight, and stifness•to•weight ratios [4–7]. Proper use of composite construction results in reductions in initial and life•cycle costs [8, 9]. High costs in the con• struction industry mainly occur due to labor costs and on• site temporary works. In the case of a high•rise building and bridge construction, the construction cost and time of temporary works signifcantly afect the efectiveness of conventional reinforced concrete construction. Te con• struction process of reinforced concrete columns passes one of the critical paths. Tus, there is a need to reduce the cost and time of the on•site temporary works in the construction industry during the construction period [10, 11]. Composite construction, such as encased composite columns, is the most widely used type of composite construction. A fully encased composite column (FEC) provides improved strength, stability, stifness, freproofng, and corrosion protection [12–15]. Basically, a steel•concrete composite column com• prises either a concrete•encased steel section or a con• crete•flled tubular steel section. Steel•concrete composites are generally used as load•bearing members in a composite•framed structure. Te combined resistance to external loading in a composite column is enhanced by providing supplementary reinforcement. Tis prevents excessive spalling of the concrete under external load and fre conditions [16, 17]. So far, many studies have been Hindawi Advances in Civil Engineering Volume 2023, Article ID 5974705, 12 pages https://doi.org/10.1155/2023/5974705