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Methods for measuring and modeling the process of prestressing concrete during tensioning/detensioning based on electronic distance measurements

  • US 10,203,268 B2
  • Filed: 05/26/2016
  • Issued: 02/12/2019
  • Est. Priority Date: 12/04/2008
  • Status: Active Grant
First Claim
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1. A method for post-tensioning a concrete structure with steps comprising:

  • (a) programming a finite element model of the concrete structure, which when executed by a processor predicts coordinates of a plurality of points on the concrete structure as a function of a plurality of tensions applied to a corresponding plurality of tendons within the concrete structure;

    (b) developing a post-tensioning plan for applying the plurality of tensions, wherein the post-tensioning plan is a written document that specifies an order in which the plurality of tendons are tensioned and a tensioning force to be applied to each of the plurality of tendons;

    (c) identifying a plurality of cardinal points from the plurality of points on the concrete structure, wherein the identifying is based at least in part on the finite element model, the post-tensioning plan, the predicted coordinates of the plurality of cardinal points, and engineering experience;

    (d) attaching a plurality of retroreflectors to the concrete structure at locations corresponding to the plurality of cardinal points;

    (e) measuring at least a first range from a first electronic distance measurement instrument to a 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, whereinthe 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, andthe first location, the second location, and the third location are three different locations;

    (f) storing at least the first, second, and third ranges;

    (g) computing a first three-dimensional coordinate of the first cardinal point, based at least in part on the first, second, and third ranges;

    (h) applying a first tensioning force to a first of the plurality of tendons as specified by the post-tensioning plan;

    (i) measuring at least a fourth range from the first electronic distance measurement instrument to the first cardinal point, a fifth range from the second electronic distance measurement instrument to the first cardinal point, and a sixth range from the third electronic distance measurement instrument to the first cardinal point;

    (j) storing the fourth, fifth, and sixth ranges;

    (k) computing a second three-dimensional coordinate of the first cardinal point, based at least in part on the fourth, fifth, and sixth ranges;

    (l) modifying the post-tensioning plan based at least in part on the finite element model, the applied first tensioning force, the first three-dimensional coordinate, the second three-dimensional coordinate, and the engineering experience; and

    (m) applying a second tensioning force to a second of the plurality of tendons as specified by the modified post-tensioning plan.

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