Deflection monitoring system

Deflections in supporting structures, due to external stress factors, can be detected with one or more energy beams generated along a path adjacent to the structure. Receivers are positioned in or near the path. Target blocks are positioned along the support structure. When a deflection occurs in the support structure, the targets are concurrently displaced into or out of the path. The receiver registers a change in state and activates an alarm. Multiple beams can be used to detect deflection in one of a number of predefined zones, the alarm indicating the zone in which the beam path was broken by the deflection.