AN INTEGRATED SYSTEM AND METHOD FOR MEASURING DEFORMATIONS AND/OR STRESSES IN ONE-DIMENSIONAL ELEMENTS

• US 20190316979A1
• Filed: 11/21/2017
• Published: 10/17/2019
• Est. Priority Date: 11/22/2016
• Status: Active Grant

• Current Assignee: Politecnico di Torino
• Original Assignee: Politecnico di Torino
• Inventors: TONDOLO, Francesco
• Granted Patent: US 11,092,499 B2
• Time in Patent Office: Days
• CPC Class Codes: G01L 1/02 by hydraulic or pneumatic means
• CPC Class Codes: G01L 9/0045 Diaphragm associated with a buried cavity

Abstract

An integrated measuring system (9) comprises a structural element (10) for building constructions, having an internal cavity (14), hermetically closed to contain a compressible fluid (16), and a measuring system (12) for measuring stresses and/or deformations on the structural element (10), measuring system (12) whereby it is possible to measure the pressure and temperature of the fluid (16) so as to measure a change in fluid pressure and determine a variation of the volume of the cavity (14) resulting from an action (F) imparted to the structural element (10).

Claims

1. Integrated measuring system (9), comprising:

a structural element (10), adapted to be incorporated in a building construction and elongated in a longitudinal direction, said structural element (10) having an internal cavity (14) hermetically closed or closable by means of closure means (20), said internal cavity (14) being filled with a compressible fluid (16);

a measurement system (12), adapted to measure deformations and/or stresses on the structural element (10) along said longitudinal direction, the system comprising a pressure measuring device (18) in contact with the fluid in the internal cavity (14), said measurement system (12) further comprising a device for measuring the temperature of the fluid (16) and/or the temperature of the inner wall of the cavity (14), in such a way that the system is able to determine a volume variation of the cavity (14) by measuring a pressure and temperature variation of the fluid resulting from an action (F) imparted to the structural element (10),

wherein the cavity (14) extends along a direction substantially perpendicular with respect to said longitudinal direction.

2. A system according to claim 1, wherein the cavity (14) intersects a central longitudinal axis (11) of the structural element (10).

3. A system according to claim 1 or 2, wherein the cavity (14) passes through the structural element (10).

4. A system according to any one of the preceding claims, wherein the compressible fluid (16) is a gas or a liquid/gas mixture.

5. A system according to any one of the preceding claims, wherein the pressure measuring device (18) is immersed in the fluid (16).

6. A system according to any one of the preceding claims, wherein the closing means (20) are configured so as to allow the connection between the devices measuring pressure and/or temperature (18) with a power and/or data transfer system (22), adapted to power said devices (18) and/or to communicate the data collected within the cavity (14).

7. A system according to any one of the preceding claims, in which a radially outer projection (24) is associated to the structural element (10) and is placed at the cross-section of the structural element (10) on which the cavity (14) lies, said projection having a cross-section having an area substantially equivalent to the area of the cross-section of said cavity (14).

8. A system according to any one of the preceding claims, wherein the structural element (10) is a metallic bar for reinforced concrete.

15. A structural element (10) adapted to be incorporated in building constructions, comprising a plurality of integrated measuring systems (9) obtainable according to any one of claims 1 to 8.

9. Method for measuring deformations and/or stresses along a longitudinal direction of a structural element (10) elongated in the longitudinal direction, said structural element (10) being adapted to be incorporated in a building construction and being subjectable to an action F, the method comprising the steps of:

a) providing at least one cavity (14) internal to the structural element (10), oriented in a direction substantially perpendicular with respect to a central longitudinal axis (11) of the structural element (10);

b) filling the cavity (14) with a compressible fluid (16) and sealing the cavity (14) by means of closing means (20);

c) associating a measurement system (12) to the cavity (14), said measuring system (12) comprising a measuring device (18) of the pressure of the fluid (16), and a device for measuring the temperature of the fluid (16) and/or the temperature of the inner wall of the cavity (14);

d) measuring the pressure and temperature variations of the fluid (16), determining a variation of volume of the cavity (14), and establishing a relationship between said volume variation and a longitudinal deformation of the structural element (10).

10. A method according to claim 9, wherein step (b) is carried out by filling the cavity (14) with a gas or a gas/liquid mixture.

11. A method according to claim 9 or 10, wherein the cavity (14) intersects a central longitudinal axis (11) of the structural element (10).

12. A method according to one of claims 9 to 11, comprising the step of determining a priori a relationship between temperature and deformation of a structural element (10) subject to design operative conditions, and calibrating the system converting the temperature and pressure variations of the fluid (16) to the longitudinal deformation and/or stress of the structural element (10), so as to exclude from the calculation the contribution of a temperature variation of the fluid.

13. A method according to one of claims 9 to 12, comprising the step of applying an additional radially outer projection (24) to the structural element (10), placing said projection (24) at the cross-section of said structural element (10) on which the cavity (14) lies in such a way as to restore the area of material missing due to the presence of the cavity (14).

14. A method according to one of claims 9 to 13, wherein the structural element (10) is a metallic bar for reinforced concrete.