Seismic performance of CBF’s single steel angle brace under several variable amplitude loadings

Abstract Constructing seismic seismic-resistant structures is essential to be carried out in earthquake-hazard areas. A concentrically Braced Frame System (CBF) is an earthquake-resistant structure that relies on its brace to withstand seismic loading. Seismic loading is a series of loading histories composed of high (HA) and low-amplitude (LA) loading. When this loading hits the CBF system, it will perform various values of displacement. So far, many studies have been conducted to reveal seismic performance in CBF. However, studies on CBF’s response due to the variable displacement amplitude as the representation of the earthquake is still limited. This present study observed the seismic performance, i.e., strength, stiffness, and dissipated energy, of the CBF’s brace due to the variable amplitude loading. Variable amplitude loading is the loading history composed of high and low displacement amplitude levels. The brace was made of a single steel angle, L 40.40.4, and loaded with three different variable amplitude loading. Observing the dissipated energy as the main seismic performance of CBF discloses that the specimen which is loaded by the smaller number of cycles in a block amplitude reached the highest cumulative dissipated energy in the same applied displacement. This tendency is supposed to be presented since the specimen under a smaller number of loading repetitions in a block, leads to experiencing a small effect of fatigue and increases the strength in each cycle. Confirming the failure mode disclosed that all braces presented flexural and torsional buckling.