Static and dynamic characterization of a low-cost MEMS sensor for structural monitoring purposes

Italian buildings and infrastructural heritage are often ancient or characterized by a chronic lack of maintenance and, because of the seismic and hydro-geological risk levels occurring in the whole Italian territory, they are interested by high levels of vulnerability. Moreover, from the viewpoint of the life-cycle management of civil structures, the economic and social impact of maintenance is crucial. Inspections and repairs entail huge direct and social costs, due to the interruption or reduction of the structure functionality. In order to define adequate and effective maintenance programs, owners of the buildings and infrastructures need information on the actual state of the structures before damages can occur with a consequent suspension of their functionality. Such information can be collected and elaborated by means of adequate monitoring systems but their diffusion is still limited by the high cost of sensors and devices needed. In this paper a new low cost Micro Electronic Mechanical System (MEMS) accelerometer is proposed to be used for monitoring of civil structures and infrastructures. Results of laboratory static and dynamic characterization are reported in order to define the sensor sensitivity and accuracy. Since MEMS sensors measurements are affected by environmental temperature, several laboratory tests have been performed also to achieve the response of the sensor under a wide range of external operative temperatures in order to correct the acquired data. A monitoring system architecture based on MEMS sensors is also presented in detail.