Development of a Customized Wireless Sensor System for Large-Scale Spatial Structures and Its Applications in Two Cases

In this paper, a customized wireless sensor system (WSS) for structural health monitoring is developed toward large-scale spatial structures. Spatial structures are widely used in large public buildings which generally house thousands of people, therefore the safety of the buildings is a major concern for structural engineers. One of the characteristics of spatial structures is their steel construction and the material is homogeneous throughout. So the strain is commonly the most distinct parameter to indicate status of the structure. Another characteristic of spatial structures is their large-area scale, which brings problem for traditional wired monitoring systems, so an effective wireless sensor network (WSN) for structural monitoring is in urgent demand. Considering those features, the WSS development mainly focused on the sensor selection, hardware design and network customization. In this paper, a vibrating wire sensor is selected for strain measurement because of its stable, durable and anti-electromagnetic properties. For other parameters measurement, some commercial sensor products with digital signal output are adopted. Following the principle of modularization and extendibility, the hardware design is mainly based on the realization of several functional modules. All along, energy efficiency and measurement accuracy are the core design objective. The WSN is classified into four different types of topologies from basic to complex ones. They all have the common working mechanism, namely the collected data transfers via several relay from sensor nodes to sink nodes. Different types of networks are to be customized according to the configuration and scale of different structures. Finally, two typical applications are discussed in detail to verify the feasibility of the system. It can be concluded that the customized WSS is effective and durable, and well satisfies the requirement of structural status monitoring for large-scale spatial structures. Collected data have also shown that the structural stress variation is obvious under the effect of construction process and some other factors.