Analysis of Capacity and Ductility in Mortar-Filled Hollow Steel Frames with Variable Horizontal Bar Spacing

Abstract

The use of wood in the construction industry results in forest degradation, which can negatively impact the natural environment. To reduce the use of wood, alternative materials are needed. Steel is one such alternative due to the wide availability of steel products on the market. The purpose of this study is to determine the capacity and ductility of frames used as wall reinforcement by employing perforated steel filled with mortar. This research involves a hollow steel frame filled with mortar and reinforced with welded joints, with variations in the spacing between horizontal bars. The study was conducted using Extended Three-dimensional Analysis of Building Systems (ETABS) application modeling and experimental laboratory tests. The results of the capacity and ductility from the test data are compared with the results from ETABS application modeling, allowing for adjustments when modeling real-world conditions. The plane frame of the test object, designed according to the plan, was subjected to a monotonic load (pushover) on the left side until the planned deflection was reached. The results indicate that the maximum load capacity in laboratory testing for each specimen variation is lower than that predicted by ETABS modeling. The maximum capacities for Hollow Steel Frame (RBH) Type 1, Type 2, and Type 3 specimens are 2,895tf, 2,721tf, and 3,872tf, respectively, while for the ETABS application, they are 4.8tf, 5.6tf, and 5.8tf, respectively. Therefore, a reduction factor of 0.5 from the ETABS modeling results is needed for the use of similar construction in the future. The ductility values for RBH Type 1, Type 2, and Type 3 specimens were 4.61, 2.24, and 3.37, respectively.