Infrastructure–User Heterogeneous Data Interaction and Fusion of Mobile-IoT Sensing Networks in a Smart City: Application to a Footbridge

Abundant data are collected in the daily operation of infrastructures via structural health monitoring (SHM) systems. Meanwhile, user information is measured through the popularized mobile smartphones nowadays. However, these data types are insufficiently integrated or fused to extract valuable information to improve user comfort or enhance infrastructure safety. In this study, a bidirectional data interaction framework is developed to facilitate information sharing and fusion among users and the infrastructure through wired and wireless communications. The framework is applied to an overpass footbridge equipped with an SHM system. The walking patterns and dynamic information of pedestrians are extracted from the acceleration, orientation, and GPS data of smartphones. On this basis, the pedestrian load is generated and applied to the numerical model of the footbridge, and the full-field bridge responses can be calculated to realize a virtual holographic sensing. Simultaneously, the micro-environment and vibration data of the footbridge are collected from the SHM system, smartphones, and online databases. These data are formulated as the pedestrian comfort indexes, which directly determine the behavior and perception of pedestrians to their surroundings. The in-field data in a week are used to verify the applicability and performance of the developed approach. Results show that the data integration framework can improve the volume and diversity of data for infrastructures and users with satisfactory accuracy.