Wave Propagation in a Timoshenko Beam Building Model

This study analyzes wave propagation in a Timoshenko beam model of a high-rise building excited by base motion. This model accounts for wave dispersion caused by bending and is more realistic for analysis of wave propagation in high-rise buildings than shear beam and other discrete nondispersive models. The model transfer functions and impulse response functions are obtained from the analytical solution for a forced vibration response of the beam excited by base motion. The impulse response functions represent the model response to a virtual input pulse; a set of such functions at different levels is used to study pulse propagation in the beam. A parametric study of dispersion and its effects on the model transfer functions and impulse response functions is presented in terms of dimensionless parameters and in ranges corresponding to buildings. The model is validated for a 9-story full-scale RC building and smaller earthquake excitation. The results provide insight into dispersive wave propagation in buildings caused by bending, which is useful for the interpretation of impulse responses of buildings obtained from earthquake records and for the development and testing of wave methods for structural health monitoring. The results can also be used for testing numerical models for pulse propagation in buildings.