Applications of acoustic emission evaluation for civil infrastructure

Due to the state of aging civil infrastructure systems structural health monitoring and nondestructive evaluation have received increased attention recently. Events related to bridge collapses in Pennsylvania (partial) and Minnesota (catastrophic) combined with the levee failures in Louisiana have justifiably drawn the attention of the policy makers and the public at large. Therefore it appears likely that both monitoring efforts of existing systems and the development of more resilient systems will be increased. In the case of civil structures (bridges, dams, levees, and buildings) the most common type of sensors used are strain gages and accelerometers. While these sensors can be useful if used correctly they are limited in the types of data that can be gathered and are not well-suited for many applications. In contrast acoustic emission sensors are very rarely used for civil applications but can in fact provide useful information either as a stand-alone data type or to supplement the data gathered from other sensors. This paper describes several case studies where acoustic emission has been successfully used in civil infrastructure applications and summarizes both the advantages and challenges that are inherent in the method for such applications.