Behavior of Built-Up Cold-Formed Steel Stub Columns Infilled with Washed Bottom Ash Concrete

The main objective of the study is to determine the behavior of built-up cold-formed steel (CFS) stub columns infilled with washed bottom ash (WBA) concrete and also their failure mode. Five proportions of WBA as sand replacement in concrete and five specimens of built-up CFS stub columns infilled with WBA are produced in this study. There are four parts of the testing conducted: material properties of CFS, material properties of WBA concrete, mechanical properties of the connection, and mechanical behavior of built-up CFS stub columns. The result shows that the specimen with 25% WBA is reported to have the highest value of compressive strength in the material properties of WBA concrete and the mechanical behavior of built-up CFS stub column. The percentage difference of the ultimate load of the built-up CFS column filled with normal concrete and filled with WBA concrete is noted to have a range of 3% to 25%.