Characterization of Six-Degree-of-Freedom Sensors for Building Health Monitoring

Six-degree-of-freedom (6DoF) sensors measure translation along three axes and rotation around three axes. These collocated measurements make it possible to fully describe building motion without the need for an external reference point. This is an advantage for building health monitoring, which uses interstory drift and building eigenfrequencies to monitor stability. In this paper, IMU50 6DoF sensors are characterized to determine their suitability for building health monitoring. The sensors are calibrated using step table methods and by comparison with earth’s rotation and gravity. These methods are found to be comparable. The sensor’s self-noise is examined through the power spectral density and the Allan deviation of data recorded in a quiet environment. The effect of temperature variation is tested between 14 and 50 °C. It appears that the self-noise of the rotation components increases while the self-noise of the acceleration components decreases with temperature. The comparison of the sensor self-noise with ambient building signal and higher amplitude shaking shows that these sensors are in general not sensitive enough for ambient signal building health monitoring in the frequency domain, but could be useful for monitoring interstory drift and building motion during, for example, strong earthquake shaking in buildings similar to those examined here.

DETRIMENTAL EFFECTS OF WIND-INDUCED BUILDING MOTION ON OCCUPANT WORK AND TASK PERFORMANCE

We present recent multidisciplinary research conducted by psychologists, engineers and physiologists investigating the effects of wind-induced building motion on wellbeing, manual task performance and cognitive performance. In a sample of actual office workers, we show that sopite syndrome is the main consequence of exposure to wind-induced building motion. Sopite syndrome, a form of mild motion sickness characterized by drowsiness and low motivation, is the main cause of reductions in work performance. Experimental research shows that biomechanical properties of the human body are influenced by the frequency of motion, which amplifies body sway and interferes with task performance at 0.5 Hz, and to a greater extent with increases in acceleration. Exposure to motion induced sopite syndrome in some participants, who performed significantly worse than unaffected individuals. A new generation of serviceability criteria should aim to minimize sopite syndrome, motion sickness, motion induced body sway, and other psychological and physiological factors, rather than only address perception thresholds, which will likely allow engineers and designers to create a new generation of buildings that will ensure an improved level of comfort and performance for building occupants.