Structural displacements measurement method - uses four photodetectors in receiver mounted on structural element

摘要

The method determines absolute and relative displacements in two directions (i.e. vertical and horizontal) of buildings etc. Currents are derived from circuits associated with a group of four photosensitive elements (R1 to R4) whose resistances are a function of the position of a light spot initially centred on the group. The spot is provided by a source (2) placed at a known distance and on stable ground. The variation of the position of the spot on the group is determined by the spatial displacement of the structural element being examined, a receiver (1) being mounted on this element containing the four detectors and allowing direct reading of the absolute or relative displacement via the intensity variation of the respective electric currents.