Damage Assessment of Concrete Bridge Decks using Impact-Echo Method

Abstract

This study presents results of a nondestructive evaluation (NDE) testing program performed to assess the damage in concrete bridge decks subjected to full-scale static and dynamic loading using the impact-loading method. The bridge decks were removed from a bridge built in 1953 in South Carolina. While in service, the concrete decks were retrofitted with FRP composite materials to repair extensive damage. Two slabs were tested by NDE in the lab after removal of the reinforcement layer. Impact-echo tests (IETs) were performed concurrently with full-scale static and dynamic load tests. The first slab was statically loaded to failure, and the second was tested dynamically with cyclic loading. IETs were performed before and after the loading sequence for each slab and between each application of cyclic loading for the second slab. Results from tests on the statically loaded slab detected a significant reduction in propagation wave velocity after failure, indicating a reduction in the slab stiffness. IETs on the dynamically loaded slab quantified the degradation of the slab during dynamic testing. Significant damage was detected earlier than by visual observance and before the slab reached service failure.