Energy harvesting from vertical pedestrian-induced vibrations of footbridges

The use of advanced sensing systems can facilitate the remote health and serviceability survey of existing infrastructures. In particular, the large number of footbridges built in many countries can greatly benefit from the implementation of smart technological solutions for data transmission and power management. Within this framework, the present paper is con-cerned with the possibility of using piezoelectric energy harvesters as electrical power source for wireless sensor nodes installed on footbridges. An efficient probabilistic computational framework has been implemented in order to provide preliminary useful results in this regard. Specifically, the vertical dynamic response of a single-span footbridge under multiple walkers is simulated by considering its first mode of vibration only, and the pedestrian load is mod-elled as a moving sinusoidal force. The scavenging device is a cantilever bimorph with piezo-electric layers made of electrospun PVDF nanofibers. It is assumed that the uncertainties are mainly related to the pedestrians’ dynamics. Therefore, the randomness of the walkers’ char-acteristics is taken into account by means of existing probability distributions whereas the arrival time is modelled through the Poisson distribution. Monte Carlo simulations have been finally performed for a particular case-study in order to estimate the electrical energy generat-ed by the device.