Environmental vibration impact on humans in buildings is caused by ground-borne vibration due to rail transit systems, road traffic, construction sites, and industrial plants. To estimate the effect of vibration on humans, it is necessary to measure the tri-axial vibrations in the vertical and horizontal directions in buildings specified in the standards regulated by ISO2631-2:2003. Vibrations in two-and threestory detached houses of wooden or steel construction were measured. The vibration amplifications caused by building structural resonance were evaluated as ratios and level differences in 1/3 octave band vibration accelerations measured at ground near substructure and floors in the 120 houses vibration measurements.

In Japan, there are many houses built in limited space as well as in close proximity to causeways and railroads, due mainly to concentration of population in the cities in recent years. Slender structures and especially 3-story houses are susceptible to vibration induced by external forces such as traffic. This effect often creates an uncomfortable environment for habitation. Because houses often have a complex geometry, it is difficult to establish the vibration characteristics of a structure. Furthermore, the response characteristics of a house will change with environmental conditions. A prototype Active Mass Damper (AMD) has been developed to address some of these issues. This has been tested in an exhibition house in Tokyo. It uses two AMD’s of 1,725N mass each for both X-axis and Y-axis. Both AMD’s are applied in X and Y directions and are installed at RooF level, they are controlled by Direct Displacement Feedback (DDFB). The test showed that the AMD could dramatically reduce vibration. Of particular note was reduction about 6dB to 8dB (L10) in the first mode of vibration even though the house mass is double the prototype target weight. Also, vibration was dramatically decreased by the AMD on 3rd floor of the house. Vibration level and comfort are important criteria for this kind of system.

A laboratory experiment was conducted to investigate the evaluation method of building habitability based on subjective responses to vibration caused by external sources. Twenty-five people participated in the experiment with 76 input stimulus conditions consisting of vibrations based on field records and sinusoidal vibrations in the horizontal direction. The subjective responses were measured in terms of "Magnitude", "Concern", and "Discomfort". The relationships between several domestic and international evaluation methods of environmental vibration and subjective responses showed that the Vibration Dose Value in which the effect of vibration duration was considered by the fourth power was the most reasonable method.

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