Laser measurement of building vibration and displacement

This paper considers four laser systems used by the Building Research Estab lishment (BRE) to investigate the behaviour of structures. Lasers enable re mote measurements of vibration and displacement to be taken where access to a structure is difficult or where fire, explosion or structural collapse c reates a hazardous environment. Each system will be described, and its use illustrated using measurements taken on real structures. The four systems a re: 1. Laser Interferometer: This is used to measure the velocity of vibration of a structure under ambient loading. 2. 3D-Laser Survey System: This is used to track the movement of any number of targets on a structure under load. 3. VHS Laser System: This is used to measure displacement of a target movin g at high velocities. 4. Tracking Lasers: This is used to track the angular displacements of a ta rget.