Prediction of remaining life of RCC sewer manhole using smart material-based EMI technique for sustainable environment.

Manholes are vital component of the sewerage system; they are often damaged due to concrete corrosion, hydrogen sulphide (H2S) gas released by sewage effluent and vehicular loading. Due to large number of accidents occurred on the road, there is need for supervision of manholes so that it can be replaced when it is about to damage. In this paper, three different manholes were tested according to Indian standard code IS 12592 (2002). At the same time, using electro mechanical impedance (EMI) technique, the damage quantification was done using root mean square deviation (RMSD) for the obtained signature of the manholes with different damage stages. Three PZT sensors were bonded using epoxy, one each on top and bottom of manhole cover and third at the frame of the manhole. It was found that the PZT bonded at bottom captures the damages well than the PZT bonded on the top of cover, but it shows large variation when the crack line passes through the PZT bonded place, the PZT bonded on the frame shows abrupt variations with the damage. Hence, PZT sensor pasted on top of manhole cover was found to be well correlated to the damage stages. The effective structural parameters were extracted using PZT sensor; moreover, for all the three manhole structures, the structural damping was identified for different damage states. A model was developed including all three manholes with more than 95% confidence level for estimating the remaining life of manhole.