Seismic Design Forces. II: Flexible Nonstructural Components

This paper presents two simplified methods for calculating the seismic force coefficients for flexible nonstructural components in building structures. The methods utilize the dynamic characteristics, expressed in terms of the fundamental periods and damping ratios, of the component and the supporting structure to calculate the force coefficient. The cases with the building period and component period known or unknown are considered. The formulas with less information tend to provide more conservative estimates of the force to cover the worst case situations. The new formulas now include the effect of possible resonance with higher modes. The validity of the proposed formulas is verified by a comprehensive numerical study of several buildings of different fundamental periods.