The forces imposed by pedestrians on structures are an important topic for civil engineering, and are an active area of research for VES. With the help of some undergraduate students, VES carried out some walking tests on a 110 metre long, single-tower cable-stayed footbridge (see Figure 1) to study the synchronisation among walking pedestrians on the bridge. Six volunteers (shown in Figure 2) were instrumented with wireless accelerometers, and each pedestrian had one accelerometer placed on their lower back and one accelerometer on their right foot.
The data from these sensors were used to estimate the forces exerted by the volunteers on the bridge which could then be used to simulate the response of the footbridge. To measure the bridge response, a set of 17 wired accelerometers was arranged along the deck; Figure 3 shows the data acquisition system for the wired sensors. Twenty walking tests were conducted, with different walking speeds or spatial arrangements. During some tests, a metronome was used to control one volunteer’s speed, while other tests involved unprompted walking. Figure 4 shows a 10-scecond time history of vertical acceleration in the bridge deck by wired sensor, and also the accelerations of one pedestrian during walking.