Development of Surface-Mounted Smart Piezoelectric Modules for Condition Assessment of Bridges

In-situ, real-time structural health monitoring (SHM) of civil infrastructure via piezoelectric materials (PZT) is an emerging, sustainable method to ensure structural safety and integrity. In this study, a smart surface-mounted PZT patch system and an embedded PZT cement module system were developed to determine the wave modulus of elasticity (WMoE) of concrete through a combined experimental and numerical investigation. Concrete beams and a concrete panel were evaluated to identify the feasibility of utilizing the two smart PZT systems to determine the WMoE at different ages. The key parameter of the study was to determine the time of flight (ToF) of the first Rayleigh wave (R-wave) package from the surface-mounted PZT patch system or the first shear wave (S-wave) package from the embedded PZT cement module system of propagating waves. The experimentally measured WMoE from the two smart PZT systems were about 11 percent (maximum) higher than the SMoE of the concrete obtained from the compression test. The experimental results also indicated that the surface-mounted PZT patch system produced higher WMoE values than the embedded PZT cement module system, but within a range of 4 percent. The orientation of the embedded PZT cement modules affected the clarity and magnitude of the propagating wave. The established FE model for beams validated the results of the experimental evaluation. The measured WMoE also varied with the dimensions of the structures, and the WMoE values measured from a narrower, deeper structure were smaller than the ones from a wider, shallower structure. Overall, the surface-mounted PZT system proved to be as effective as or even better than the embedded PZT cement module system in determining the of WMoE concrete with a certain degree of confidence and in assessing concrete properties.Pacific Northwest Transportation Consortiu