Research on Building Vibration Response and Propagation Laws Under Variable-Frequency Vibration Excitations

The To elucidate the propagation laws of vibrations generated during the operation of variable-frequency equipment and the influence of such vibrations on building structures， an engineering project incorporating such equipment was investigated through field vibration measurements. Vibration response data were collected at the equipment source， along multiple propagation paths， and on different floors of the building， enabling an examination of the effects of excitation frequency， propagation distance， and spatial direction. The results indicated that the vibration propagation in soil exhibited obvious frequency-dependent characteristics， with the vertical acceleration transmissibility decreasing as the operating frequency increased. Notably， the vibration propagation showed significant directional anisotropy， with the horizontal transmissibility 30% to 50% higher than the vertical one. Vibration amplitude decayed approximately exponentially as the propagation distance increased. Based on the measured data， a quantitative relationship between vertical acceleration transmissibility and propagation distance considering excitation frequency was established. The relationship revealed that vibrations attenuated to the ambient background level at a distance of approximately 200 to 220 m from the vibration source. The vibration distribution inside the building was jointly governed by floor height and structural configuration， and distinct floor vibration response characteristics in different directions were observed due to differences in structural stiffness.