Resonance measurement and vibration reduction analysis of an office building induced by nearby crane workshop vibration

Abstract

Tests were conducted on a 6-storey office building and factory building near where abnormal horizontal vibrations often occurred. The floor acceleration responses of the building were measured under the condition of crane operation, which was believed to be one of the sources of the vibration. A one-third octave spectrum and weighted acceleration levels were calculated from the measured floor acceleration time histories to assess human comfort levels. The modal parameters of the building were identified using the frequency domain decomposition method. The field test results indicated that the small crane's excitation frequency during the start and stop operations in the nearby factory was 3.6 Hz, which was the same as the fundamental natural frequency of the building. The resonance phenomenon between the building structure and the crane excitation caused the abnormal horizontal vibration. Finally, the influence of adjusting the excitation frequency, the excitation intensity, and the connection form of the foundation slab on the vibration responses was analyzed. Results showed that when the excitation frequency was adjusted to stagger the natural frequency of the structure by 20%, the acceleration level resulting from the same excitation could be reduced by half. The excitation intensity, the difference between the frequencies of excitation and structure was found to be the key factor influencing the structural resonance response.