Vertical acceleration response of structure considering the influence of floor slab

Abstract:

In addition to horizontal seismic actions, vertical ground motion also significantly affects the damage state of non-structural components such as suspended ceilings. However, there is currently insufficient research on the vertical acceleration response of structures under vertical ground motion. To address this gap, a case study is conducted using a real frame structure with different-sized floor slabs. This study performs vertical mode analysis of the structure and conducts time history analyses under four categories of seismic motions, totaling 80 records. The vertical acceleration response of the structure and its influencing factors are studied, and a standardized vertical design response spectrum for seismic analysis of non-structural components is fitted. The results show that the vertical peak floor acceleration amplification factor for the floors range from 1.21 to 8.16, which is much higher than the horizontal amplification factors specified in various national standards. The vertical acceleration response of the structure is influenced by the self-vibration frequency of slabs, the dominant frequency of vertical ground motions, the height of the floors and the position of slabs within the floors. The vertical response of the structure may be amplified significantly due to the vertical flexibility of the structure, which have obvious adverse effects on non-structural components. Additionally, a standardized design spectrum and mathematical expression for vertical acceleration of the structure are obtained, which can be better used for the seismic analysis of non-structural components.