# US 9,038,478 B2 · Method for determining the fatigue capital of a cable > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,038,478 B2 - Document ID: US9038478B2 - Status: Granted - Kind: B2 - Application number: 14/123,489 - Filed: 2012-06-04 - Published: 2014-07-10 - Granted: 2015-05-26 - Earliest claimed: 2011-06-03 - Assignees: Soletanche Freyssinet - Applicants: Gilles Hovhanessian; Alexandre Chaperon; Erik Mellier - Inventors: Gilles Hovhanessian; Alexandre Chaperon; Erik Mellier - Web page: https://patentgrep.com/patent/US9038478B2 ## CPC - G01N 3/32: by applying repeated or pulsating forces - G01M 5/0025: {of elongated objects, e.g. pipes, masts, towers or railways (G01M5/0058 takes precedence)} - G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q) - G01M: TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR ## Abstract The invention relates to a method for determining the fatigue capital of a cable supporting a civil engineering structure, the method including: a measuring step (S1, S2) during which the normal tensile stress in the cable and the bending stress in the cable are measured in a synchronized manner so as to obtain the compound stress in the cable; a counting step (S3) during which a count of the number of stress cycles, depending on the amplitude of the stress, is carried out from the measured compound stresses; and a step (S4) of assessing the fatigue capital of the cable during which the fatigue capital of the cable is determined by comparing the count, carried out in the counting step, with a pre-set Wohler curve for the cable. ## Claims ### Claim 1 A method for determining a fatigue capital of a cable supporting a civil engineering structure, wherein the method comprises: a measurement step during which a normal tensile force on the cable and a bending force on the cable are synchronously measured so as to obtain a compound force on the cable; a counting step during which, based on the measured compound forces, a count of a stress cycle number as a function of an amplitude of the force is realized; and a step of evaluating the fatigue capital of the cable, during which the fatigue capital of the cable is determined by comparing the count carried out during the counting step with a Wöhler-type curve previously determined for the cable. ### Claim 2 (depends on 1) The method of claim 1, wherein the normal tensile force on the cable is measured directly. ### Claim 3 (depends on 1) The method of claim 1, wherein the normal tensile force on the cable is measured indirectly. ### Claim 4 (depends on 1) The method of claim 1, wherein measurement of the bending force on the cable is directly realized. ### Claim 5 (depends on 1) The method of claim 1, wherein measurement of the bending force on the cable is realized indirectly. ### Claim 6 (depends on 5) The method of claim 5, wherein the measurement of cable movements is realized in a shock absorber placed on the cable to dampen transverse vibrations. ### Claim 7 (depends on 1) The method of claim 1, wherein tensile and/or bending measurements are realized at a frequency on the order of 1 Hz to 1 kHz. ### Claim 8 (depends on 1) The method of claim 1, wherein the measurement step is not realized continuously from the moment of cable installation, and wherein the measured data are used to extrapolate from loads before and after the measurement period. ### Claim 9 (depends on 1) The method of claim 1, wherein the measurement step is realized continuously from the time of cable installation so as to measure the tensile and bending forces on the cable from the time of its installation. ### Claim 10 (depends on 1) The method of claim 1, wherein the counting step is realized by means of rainflow counting. ### Claim 11 (depends on 1) The method of claim 1, wherein history or extrapolation of past loads is used to compare the fatigue actually experienced by the cable with the assumptions made at the time of construction. ### Claim 12 (depends on 1) The method of claim 1, wherein extrapolations of future loads are used to estimate a capacity or residual lifetime of the cable with respect to fatigue. ### Claim 13 A device for determining the fatigue capital of a cable supporting a civil engineering structure, the device comprising: means for measuring an overall tensile force on the cable; means for measuring an overall bending force on the cable; means for counting a number of stress cycles as a function of an amplitude of tensile and bending forces experienced by the cable; and means for comparing the counting carried out by the counting means with a Wöhler-type curve previously established for the cable. ### Claim 14 (depends on 13) The device of claim 13, further comprising alert means for automatic notification whenever a capacity or residual lifespan of the cable is reduced below a predetermined threshold. ### Claim 15 (depends on 13) The device of claim 13, wherein the anchoring device of the cable on the civil engineering structure comprises a shock absorber that integrates a sensor for measuring the cable's bending force. ### Claim 16 (depends on 2) The method of claim 2, wherein the normal tensile force on the cable is measured using a load cell. ### Claim 17 (depends on 3) The method of claim 3, wherein the normal tensile force on the cable is measured using a strain gauge placed on the anchor or on the cable. ### Claim 18 (depends on 3) The method of claim 3, wherein the normal tensile force on the cable is measured by measuring a force on one of a plurality of strands of the cable. ### Claim 19 (depends on 3) The method of claim 3, wherein the normal tensile force on the cable is measured by a vibrating chord method and using measurement of normal frequencies of vibration of the cable. ### Claim 20 (depends on 5) The method of claim 5, wherein measurement of the bending force on the cable is based on a measurement of cable movements in a plane intersecting an axis of said cable and at a known distance from an anchorage of said cable.