Seismic Improvement of LSF Structures during Nonlinear Static and Spectral Dynamic Analyses

Light Steel Frame (LSF) structure, as a new and widely used structural system, has attracted the attention of design engineers. The LSF structure has advantages such as light weight, reduced earthquake force, and fire resistance. One of the disadvantages of the LSF is the height limitation. The use of braces can increase the height of the LSF. This study investigates the integration of steel X-braces within LSF structures to enhance their structural performance. A 2-story LSF was modelled using SAP software, and the results were compared and confirmed using literature data. Structures were evaluated during nonlinear static (3 loading patterns) and spectral dynamic analyses. Seven different engineering codes, including AASHTO2007, AS1170-2007, BOCA96, Chinese2002, EuroCode8-2004, IBC2006, Iran2800 and Italian3274, have been used in the spectrum dynamic analyses. For the seismic improvement of the LSF structure, a steel brace was used. The results showed that the steel brace caused a story displacement of 33.96% in response to three types of static nonlinear loads and a spectral dynamic load. Additionally, it led to an increase in bending moments of about 52.56% under two nonlinear static load cases, and an increase in shear forces of 59.39% under both nonlinear static and spectral dynamic load conditions.