Characteristics of the first-mode vertical vibration of buildings based on earthquake observation records

Abstract

This study focuses on the first-modal natural periods and damping ratios of buildings in the vertical direction. An auto regression and exogenous (ARX) model is used to identify each vertical natural period and damping ratio. The targets comprise over 3,000 earthquake observation records for 18 buildings comprising reinforced concrete, steel and reinforced concrete, and steel structures. The identified values are summarized for each structural type, and their characteristics are discussed in view of the input amplitude and height of the buildings, compared to the natural period and damping ratio in the horizontal direction. Based on the results, a simple estimation equation is provided for the first-mode vertical natural period.