Analysis of strengthening Encased Composite Columns with Corrugated and Flat Sheets

Background: The rehabilitation of composite columns using appropriate techniques creates several challenges for design engineers. Determining the maximum load capacity of the strengthened composite column is difficult. To address this issue, the present work undertakes a parametric investigation using experimental and ABAQUS simulation software. Aim: This study aims to examine the design equation of composite columns as outlined in Eurocode 4, to revise the equation design associated with strengthened composite columns to determine their ultimate load capacity. Methods: Twenty-three models of strengthened composite columns were created, each varying in parameters based on external retrofit techniques, including corrugated steel sheets, spiral steel sheets, and flat steel sheets. Results: The results indicate that there is an agreement between the modified equations and the finite element results, with an average of 99.15%. There is also an agreement between the modified equations and the experimental results, with an average of 94.30%. Increasing the thickness of both corrugated and flat steel sheets by 0.4, 0.8, 1.2, and 1.6 mm enhances the ultimate load capacity of the C5-R/1/1 and C6-R/1 composite columns, with a percentage of 5.1%, 11.6%, and 17% for the former and 11%, 22%, and 27% for the latter.