Delamination Detection and Location in Concrete Deck by Modal Identification

Abstract

This paper addresses delamination detection and location in reinforced concrete decks from dynamic characteristics. To investigate the effects of delamination on the modal parameters, the appropriate finite-element models are established for concrete decks. The delaminations with different sizes and locations are introduced into several models as damage scenario. The modal analyses demonstrate that the delaminated models' natural frequencies are reduced and mode shapes are irregular compared to those of non-delaminated decks. The changes in modal properties depend on the delamination sizes, locations and mode orders, consequently they can indicate the degree of damage and location. The transient analyses are carried out and three distinct excitations are applied. The modal frequencies extracted from the responses are capable of showing the delamination occurrence. The method followed in this research provides a feasible way for delamination detection in bridge decks using vibration data. This is cost-effective and real time contrasted to conventional techniques which require field tests and bridge closure.