A Study of Human Reaction to Building Vibrations Due to Occupants’ Movements

Ava Mohebbi

Abstract


 

Excessive vibrations in building structures due to occupants’ movements such as walking have become prevalent. This is mainly due to the use of higher strength construction materials, long-span column-free architectural designs, and use of equipment highly sensitive to small levels of vibrations such as MRI machines and electron microscopes. Therefore, it is important that the building designers use reliable vibration limits for the level of acceptable vibrations to humans. Current standards and design guides in the U.S. limit the vibration levels based on peak or root-mean-squared (r.m.s.) of acceleration. Past research studies have shown that these parameters do not provide reliable means for the evaluation of building vibrations. A more reliable vibration evaluation criterion, called “Vibration Dose Value” or VDV, has been introduced and recommended for use by the International Standardization Organization and the British Standards. It has been shown that VDV provides consistent results in terms of the assessment of human reaction to vibrations generated by mechanical equipment. However, currently there is not any reliable VDV limits for building vibrations due to people movements. Therefore, this paper presents a research study to establish relationships between VDV and other vibration parameters to come up with limits for acceptable levels of VDV. It attempts to answer the following research questions: 1. Can VDV be related to other vibration parameters such as peak acceleration (aw,p) or the maximum one-second running root-mean-squared of acceleration (MTVV) to establish limits on acceptable building vibrations to humans?, and 2. Can such limits be reliable and verified against subjective measurements? Vibration testing and measurements on three large commercial buildings were conducted. Using the collected data, relationships between various vibration evaluation parameters (VDV, aw,p, and MTVV) have been established. Frequency-weighting functions from four different international and British standards were used. Using the relationships developed between the parameters and the documented limits for aw.p and MTVV, new limits for VDV were recommended. These limits were then compared to the typical values recommended in the literature for other applications. In addition, subjective reactions of the building occupants participated in this study have been collected. They were then compared to the suggested limits in this study. From this study it was found that consistent relationships between VDV and aw,p, and VDV and MTVV do exist. The comparison of the limits with the subjective evaluations showed that the VDV limits for acceptable vibrations suggested in this study can be used for the assessment of building vibrations due to human movements. The results presented here can be used by engineers and architects to more reliably assess building vibrations due to human movements.


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