Patent ID: 6016708
Filing Date: 2000-01-25
Classification: G01M

Abstract:
A strain measuring apparatus, comprising:a strain gauge input unit for receiving a variation amount of the electric resistance value of a strain gauge attached to a predetermined steel member in a strain direction, a parallel direction, or a vertical direction when a predetermined weight is applied to the steel member which is used for analyzing a stability of the strain measuring apparatus;a signal converting unit (AD part) for converting a variation amount of the electric resistance value of a strain gauge which is inputted as an analog value from the strain gauge input unit into a digital value;a controller (CPU part) for receiving a variation difference amount between a strain degree obtained by applying a weight to an initial steel structure and a strain degree obtained by applying a weight to a steel structure having a hole formed at a predetermined portion of the steel structure, from the strain gauge input unit, and controlling to measure a strain in the steel structure using the variation difference amount and the following equations 1 and 2;a control command input unit (Keypad part) for inputting an initialization command for initializing the strain measuring apparatus, a radius of the hole formed in the steel structure, a distance between the center of the hole and the center of the strain gauge attached to the steel structure and an external operating signal including a proceeding command which represents a testing procedure into the controller; anda display unit (LCD part) for displaying the operating procedure of the controller and the strain measured, whereby it is possible to measure a strain of the steel member at a construction site in which a steel member is provided, wherein the following equation are satisfied: ##EQU14## where .delta..sub.x represents a strain of a steel structure which is to be measured;.DELTA..epsilon..sub.r represents a varied amount in a radial direction;.DELTA..epsilon..sub..theta. represents a variation amount in a tangent direction;.nu. represents a Foason ration of a material (0.3);E represents an elastic coefficient of a material (2.1.times.10.sup.6 kg/cm.sup.2);.nu. represents R/R.sub.0 ; and.alpha. represents an angle in a strain direction (parallel: 0.degree., and vertical: 90.degree.).