###### Abstract  
Structural Health Monitoring (SHM) is essential to identifying problems that may cause human and material losses produced by disastrous and unexpected structural failures. The dynamic characterization of civil structures adopting SHM systems provides, at a particular moment, accurate information about the current structural response. When considering a proper SHM strategy and affordable economic investment for the maintenance required by structures, it is possible to safeguard the original structural parameters and avoid potential failures. However, traditional SHM systems are not desirable due to the large economic investments involved and demand for exhausting fieldwork. This research presents the design, implementation, and validation of a low-cost SHM system composed of a Wireless Sensor Network (WSN) and a base station in order to identify dynamic properties from the measured structural response. A set of small- and full-scale experimental tests were conducted to validate the WSN system using a wired traditional SHM system. Vibration data recorded through the low-cost SHM system were processed and compared to determine the natural frequencies, mode shapes, and damping properties of different structures by computing modal identification techniques, frequency analysis, and logarithmic decrement. The obtained dynamic characterization results from small- and full-scale experimental testing conclude that the low-cost SHM system can reliably identify the dynamic properties of the tested structures. This proposal provides an inexpensive, functional, and innovative alternative for SHM regarding traditional monitoring systems. Structural Health Monitoring (SHM); dynamic characterization; structural response; low-cost SHM system; Wireless Sensor Network (WSN) +
Footnote †: journal: Applied  
doi: 10.3390/0  
the construction process's quality and validating the computational structural designs is relevant to the initial conditions of an infrastructure project, which should then be subjected to strict procedures of inspection and SHM strategies [4]. Although non-destructive evaluation testing has been carried out on structures, a manageable and efficient evaluation approach, the deterioration of structures demands comprehensive assessments of the prevailing condition of such structures, employing effective monitoring and maintenance strategies [5]. Since the first SHM implementations in previous decades, the traditional SHM system was used and conceived principally as a base station and a sturdy wired-sensors network. In addition to the high purchase and maintenance costs, these characteristics involve particular difficulties in relocating and installing the monitoring system components [6]. As civil structures age, they progressively deteriorate and may suddenly collapse; these conditions are often assumed improperly by people in charge of the operation and maintenance of civil structures. Owners neglect to implement an adequate SHM system because the economic implications are considerably expensive and \"inconvenient\". The expensive components of wired traditional monitoring systems consist of data acquisition and transmission systems, wired devices, sensor classes, and fieldwork costs. Furthermore, the setting times of these monitoring systems can be hours or even days, depending on the structural geometry and spatial location of the SHM plan [7]. If SHM systems were to be considered for existing infrastructure and design standards of new civil structures, detecting the decaying infrastructure and regulating a formal methodology needed to identify structural damage in future scenarios would be possible [8]. The simplified installation and reduction in economic investments provided by WSN monitoring systems with innovative features have made them attractive, efficient alternative strategies for SHM.