These photographs show a recent ambient modal test of the seven-story building shown in Figure 1. The purpose of test was to check the feasibility of using wireless sensors to monitor lateral building vibrations. The test was carried out by the members of the Vibration Engineering Section shown in Figure 2.
Acceleration measurements were taken, using both wired and wireless accelerometers. The accelerometers used are shown in Figure 3, the wired accelerometers are connected to a cable reel as shown in Figure 3 and then the cable reel carries the signal to the data acquisition system shown in Figure 4. Figure 5 shows a 50 second portion of the signals recorded. Because the accelerometers are oriented horizontally, the signals have a mean value of zero or very close to zero. Figure 6 shows a zoomed in version of the signal between 18 and 22 seconds. Despite the signal from the wireless sensor containing slightly more noise than the wired sensor, broadly speaking there is good agreement between both sensing systems.