Ultimate Load Capacity of Washed Bottom Ash Concrete Filled in Perforated Built-up Cold-formed Steel Column

Perforated cold-formed steel (CFS) is established in the steel sheets by using a roller, presser, and bender, and formed holes on the steel surface by using a driller at a normal temperature that is typically used in construction. Perforated CFS supports green engineering by reducing material use, enabling recycling, and improving energy efficiency. Perforated CFS offers a lot of advantages and is suitable to utilise as a structural and non-structural component but they are also easily exposed to structural integrity issues for instance buckling, web crippling, and torsion. With the intention to minimise the issue, perforated CFS is proposed to be modified to become a perforated built-up CFS (PBCFS) section and filled with special concrete. The special concrete with lightweight condition, which uses waste material as a replacement for traditional material to solve environmental issues such as air pollution, soil pollution, and groundwater pollution is introduced. The high usage of traditional materials such as cement, sand, and gravel affects environmental issues such as high carbon emissions, depletion of natural resources, water pollution, and toxicity. Consequently, the main objective of the study is to determine the ultimate load of washed bottom ash (WBA) concrete filled in perforated back-to-back built-up CFS and examine the failure mode of the column. WBA is categorised as a waste product that is collected from the washing process and used as sand replacement in full percentage in concrete. The column of WBA concrete filled in PBCFS is tested through an axial compression load. From the result and discussion, the ultimate load of the PBCFS column with WBA is reported to increase by 5.70% and 12.38% when compared with PBCFS without WBA concrete for web holes, and web and flange holes, respectively.