1st Croatian Conference on Earthquake Engineering 1CroCEE 2021

The latest middle and high intensity seismic events have demonstrated that the potential seismic risk of nonstructural elements compromises a building's overall seismic performance, affecting especially the building operability. Additionally, nonstructural elements account for a considerably large fraction of the total earthquake economic losses and total building costs. Several international building codes provide methods to approximate the seismic acceleration demand on nonstructural elements; however, the provided guidelines may not accurately estimate the actual seismic demand leading to unconservative designs of acceleration-sensitive nonstructural elements. This study compares the acceleration demand on nonstructural elements calculated by using international building codes and state-of-the-art estimation methodologies with actual floor acceleration response spectra from nonlinear time history analysis. Two moment-resisting steel frames of three and nine stories were selected as case-study buildings. The FEMA P-695 far-field ground motion set was scaled to an equivalent design intensity and it was used as the input seismic load. The floor absolute accelerations were recorded on the first and last stories of both buildings and the median floor absolute acceleration response spectra were calculated. The spectral floor accelerations were determined considering a wide range of nonstructural periods and the results were compared with the estimated floor spectral acceleration obtained from the building code provisions and the novel methodologies. The results point out that current building codes tend to mislead the design of nonstructural elements by underestimating the actual acceleration demand on these components. On the other hand, the state-of-the-art methodologies provide a better estimation of the acceleration demand on nonstructural elements without the need for conducting nonlinear time history analyses.