Patent ID: 8209134

Claim:
A method for measuring structural health of a civil structure by experimentally testing a finite element model of the civil structure, with steps comprising: (a) programming the finite element model of the civil structure, wherein the civil structure is selected from the group consisting of a bridge, a building, a crane, a tower, a dam, and an amusement park ride; (b) identifying a first cardinal point on the civil structure; (c) determining a first set of theoretical coordinates of the first cardinal point, wherein the first set of theoretical coordinates are determined based at least in part on the finite element model for the first cardinal point; (d) attaching at least one retroreflective target to the first cardinal point, wherein the retroreflective target attached to the first cardinal point has a known mechanical relationship and a known optical relationship with respect to the first cardinal point; (e) measuring at least a first range from a first electronic distance measurement to the first cardinal point, a second range from a second electronic distance measurement instrument to the first cardinal point, and a third range from a third electronic distance measurement instrument to the first cardinal point; wherein the first electronic distance measurement instrument is at a first location, the second electronic distance measurement instrument is at a second location, the third electronic distance measurement instrument is at a third location; the first location, the second location, and the third location are three different locations in a stable reference coordinate system; and the first, second, and third electronic distance measurement instruments are coordinated by a central processor; (f) determining a first set of experimental coordinates of the first cardinal point, wherein the first set of experimental coordinates is determined at least in part based on the first range, the second range, and the third range; (g) determining a first residual vector from the first set of theoretical coordinates to the first set of experimental coordinates; and (h) determining at least a first structural health parameter of the civil structure based at least in part on the first residual vector.