Damage detection

Engineers at MIT have developed a new technique for detecting damage in concrete bridges and piers that could increase the safety of ageing infrastructure by allowing easier, more frequent, onsite inspections that don't interfere with traffic or service.

The technique involves use of a hand-held radar device that can "see" through the fibreglass-polymer wrapping often used to strengthen aging concrete columns to detect damage behind the wrapping not visible to the naked eye. Such damage can occur on the concrete itself, or to areas where layers of the wrapping have come loose from one another or even debonded from the concrete.

The new noninvasive technique can be used onsite from a distance of more than 10 metres (30 feet) and requires no dismantling or obstruction of the infrastructure. It provides immediate, onsite feedback.

Called FAR-NDT (far-field airborne radar nondestructive testing), the technique could prove especially advantageous for bridges that span rivers or highways, which can prove inaccessible for other inspection techniques.