Study on one-dimensional earthquake intensities for Kiewitt-8 single-layer reticulated domes

Selection of an appropriate ground motion intensity measure to be used in scaling or standardizing the ground motion records is of importance as it can be used to reduce the scatter of the obtained peak responses for different ground motion records. To identify such an adequate ground motion intensity measure for Kiewitt-8 single-layer reticulated domes, it was noted that the ground motion intensity measure could be grouped as absolute intensity and relative intensity, by considering whether the dynamic characteristics of structures were taken into account. Based on the statistics of peak displacements obtained from the time history analyses that were carried out for Kiewitt-8 single-layer reticulated dome under horizontal or vertical ground motion components of selected records, the correlation coefficients between the peak displacements of the structure and a group of selected ground motion intensity measures, including the spectral acceleration response at the fundamental vibration period, S_a(T₁), were evaluated. The results show that S_a(T₁) is an adequate ground motion intensity measure for the horizontal excitations for the considered dome. However, its use for vertical response is questionable as expected. Furthermore, the vibration period mode that controls the peak vertical displacements is usually unknown. A simple practical approach to remediate this drawback is suggested. It requires the use of harmonic analysis for horizontal and vertical excitations to identify the vibration periods at which the structure reaches its peak responses. The spectral acceleration values at the identified periods can then be used as ground motion intensity measure.