A concrete stress-free strain measuring device

Abstract

The utility model discloses a kind of concrete stress-free strain measuring devices, including strain measurement system, annular clamp of fixed stress-free bucket and telescopic rod welded on the upper portion of annular clamp;The strain measurement system is used to capture the strain signal corresponding to the change of concrete self volume under stress-free state, while auxiliary acquisition environmental temperature data;Annular clamp is used to assist fixed stress-free bucket;Telescopic rod structure is used to fixed stress-free bucket between reinforcing steel bars.The utility model has the characteristics of high precision, low error, long-term reliable.

Description

Technical Field

[0001] This utility model belongs to the field of concrete technical parameter measurement technology, specifically relating to a concrete stress-free strain measurement device. Background Technology

[0002] A stress-free bucket is a device used to isolate the concrete containing a strain gauge from the strain caused by external loads. It is typically embedded inside a concrete structure to measure the strain caused by changes in the volume of the concrete itself, and can simultaneously measure the temperature at the embedding point.

[0003] However, the traditional stress-free bucket has poor stability when facing concrete pouring and other construction loads. Due to the use of double-layered thin iron sheets with gaps in between, the bucket is easily subjected to lateral compression and buckling during installation and vibration. Once the bucket buckles, the internal stress-free environment is lost, which in turn affects the accuracy of the measurement results. Summary of the Invention

[0004] In order to overcome the above technical problems, the purpose of this utility model is to provide a concrete stress-free strain measuring device, which has the characteristics of high precision, low error and long-term reliability.

[0005] To achieve the above objectives, the technical solution adopted by this utility model is as follows: A stress-free strain measuring device for concrete includes a strain measuring system, an annular clamp for fixing a stress-free bucket, and a telescopic rod welded to the upper part of the annular clamp. The strain measurement system is used to accurately capture the strain signal corresponding to the volume change of concrete under stress-free conditions, while also assisting in acquiring ambient temperature data; providing basic data support for the performance analysis and safety assessment of concrete structures. Ring clamps are used to assist in fixing stress-free buckets and maintaining their stability.

[0006] The telescopic rod structure is used to fix the stress-free bucket between the steel bars, maintaining the accuracy and stability of the stress-free bucket's position.

[0007] The strain measurement system includes a stress-free barrel, a horizontal fixing rod, a vertical fixing rod, strain gauges, strain plates, guide holes, and wires; The inner wall of the stress-free bucket is provided with a foam material layer structure that can be compressed and concave, and the inner side of the stress-free bucket 1 is provided with an asphalt layer. The stress-free barrel has a frustum shape, wider at the top and narrower at the bottom, and is designed with a bottom but no lid. A vertical fixing rod is installed along the central axis of the stress-free barrel, and the vertical fixing rod is connected to the bottom wall inside the stress-free barrel. The horizontal fixing rod is set in the middle of the inner wall of the stress-free barrel, and the horizontal fixing rod and the vertical fixing rod are fixedly connected at the intersection. A strain gauge is installed at the intersection, and a strain gauge is bonded to the strain gauge. The wire of the strain gauge passes through the guide hole set on the vertical fixing rod and is connected to the VW-102E type full-function reading instrument.

[0008] The use of vertical and horizontal fixing rods allows for a more stable connection of the strain gauge, preventing it from shifting position during concrete pouring.

[0009] The ring clamp includes a semi-circular ring steel sheet, a rectangular perforated steel sheet, a support bar, and a connecting bolt. The semi-circular annular steel sheet is set on the outside of the stress-free barrel. The two semi-circular annular steel sheets are connected by a rectangular perforated steel sheet to form a ring structure. The ring structure consists of two rings, one above the other, which are laterally welded together by several support bars. The connecting bolt is used to fix the rectangular perforated steel sheet; by tightening the connecting bolt, the annular clamp can be pressed tightly against the outer wall of the stress-free barrel 1, ensuring that it does not slip under the influence of external loads.

[0010] The telescopic rod structure is symmetrically installed on both sides of the stress-free barrel 1. The telescopic rod includes a hollow tube, an extension tube, an annular steel sheet, two rectangular perforated steel sheets, and two connecting bolts. One end of the hollow tube is horizontally welded to the upper ring structure, and the other end is horizontally connected to the extension tube. The length of the extension tube can be freely adjusted according to actual needs. The hollow tube and the elongated tube are connected by a guide rail at one end, and the other end of the elongated tube is connected to an elastic buckle. The elastic buckle includes an annular steel sheet, a rectangular perforated steel sheet, and a connecting bolt. The annular steel sheet is welded to the end of the elongated tube, and the rectangular perforated steel sheet is welded to the annular steel sheet. The connecting bolt achieves the fixing function of the elastic buckle through the rectangular perforated steel sheet.

[0011] The opening of the annular steel sheet is set in the vertical direction, which can be fixed between two longitudinally arranged steel bars before concrete is poured, and the stress-free bucket can be fixed by clamping the elastic buckle.

[0012] The beneficial effects of this utility model are: This invention achieves the fixation of the strain gauge and the stress-free barrel from both internal and external perspectives by setting horizontal and vertical fixing lines inside the stress-free barrel, and setting an annular clamp and a telescopic rod connected to it on the outside of the stress-free barrel, with an elastic buckle at the end of the telescopic rod. This greatly improves the stability of the stress-free strain measurement device during measurement. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the overall stress-free strain measurement device.

[0014] Figure 2 This is a schematic diagram of the internal structure of the stress-free strain measurement device.

[0015] Names of the components in the diagram: 1. Stress-free barrel; 2. Horizontal fixing rod; 3. Vertical fixing rod; 4. Strain gauge; 5. Strain piece; 6. Guide hole; 7. Wire; 8. Semi-circular annular steel sheet; 9. Rectangular perforated steel sheet (I); 10. Support bar; 11. Connecting bolt (I); 12. Hollow tube; 13. Extension tube; 14. Annular steel sheet; 15. Rectangular perforated steel sheet (II); 16. Connecting bolt (II). Detailed Implementation

[0016] The present invention will now be described in further detail with reference to the accompanying drawings.

[0017] Example: This example discloses a stress-free strain measurement device; see [link to documentation]. Figure 1 and Figure 2 The system includes a strain measurement system, an annular clamp for fixing the stress-free barrel, and a telescopic rod welded to the upper annular clamp. The strain measurement system includes a stress-free barrel 1, a horizontal fixing rod 2, a vertical fixing rod 3, a strain gauge 4, a strain plate 5, a guide hole 6, and a wire 7.

[0018] The interior of the stress-free bucket 10 is equipped with a layer of foam material that can withstand pressure and retract inwards. An asphalt layer is attached to the inner surface of the stress-free bucket 10. The asphalt layer serves to reduce stress transmission and provides thermal insulation and waterproofing. The foam material layer can be compressed when the concrete expands, providing the concrete with sufficient deformation space and preventing internal stress generated by deformation from affecting the accuracy of the measurement results.

[0019] In this embodiment, a connecting structure is provided inside the stress-free bucket 1 to fix the strain gauge 4. The connecting structure includes a horizontal fixing rod 2 and a vertical fixing rod 3. The vertical fixing rod 3 is arranged along the central axis of the stress-free bucket 1 and connected to the bottom wall inside the bucket. The horizontal fixing rod 2 is located in the middle of the inner wall of the stress-free bucket 1, and the horizontal fixing rod 2 and the vertical fixing rod 3 are fixedly connected at their intersections. This connecting structure allows the strain gauge 4 to obtain a more stable connection, preventing its position from changing during concrete pouring.

[0020] The annular clamp includes a semi-circular annular steel sheet 8, a rectangular perforated steel sheet 9, a support bar 10, and a connecting bolt 11. The rectangular perforated steel sheet is welded to both ends of the semi-circular annular steel sheet. Simultaneously, the support bar is laterally welded to the upper and lower semi-circular annular steel sheets. The connecting bolt, through the horizontally symmetrically arranged rectangular perforated steel sheets, locks the annular clamp to ensure it adheres tightly to the outer wall of the stress-free barrel, preventing slippage under external loads.

[0021] The telescopic rod includes a hollow tube 12, an extension tube 13, an annular steel sheet 14, a rectangular perforated steel sheet 15, and a connecting bolt 16. One end of the hollow tube is horizontally welded to the upper annular clamp, and the other end is horizontally connected to the extension tube. The extension tube can be freely adjusted in length according to actual needs. The elastic buckle includes an annular steel sheet, a rectangular perforated steel sheet, and a fixing bolt. The annular steel sheet is welded to the end of the extension tube, and the rectangular perforated steel sheet is welded to the annular steel sheet. The fixing bolt achieves the fixing function of the elastic buckle through the rectangular perforated steel sheet.

[0022] Implementation method: When installing this stress-free strain measurement device, firstly, the strain gauge 4 is installed and fixed at the intersection of the horizontal support rod 2 and the vertical support rod 3, and the strain gauge 5 is bonded to the left side of the strain gauge 4. The wire 7 of the strain gauge 5 passes through the guide hole 6 set on the vertical fixed rod 3 and connects to the VW-102E type full-function reader.

[0023] Next, the annular steel plates 14 at the ends of the two extension tubes 13 are fitted onto the longitudinal reinforcing bars and the connecting bolts 16 are tightened. Taking into account the diameter of the stress-free barrel 1 and the spacing of the longitudinal reinforcing bars, the extension rods 13 are adjusted to a suitable position. The two annular clamps connected to the extension rods 13 are symmetrically fitted onto the outer wall of the stress-free barrel 1 and the connecting bolts 11 are tightened. At this point, the stress-free strain measuring device is installed and concrete pouring can be carried out.

[0024] After the concrete in stress-free bucket 1 has initially set, the initial value of strain gauge 4 is read using a reading instrument. The next batch of concrete is poured, covering stress-free bucket 1. The values ​​of strain gauge 4 are continuously monitored. Based on the monitored strain count values, the stress-free strain of the fully graded concrete is analyzed and calculated.

[0025] The stress-free bucket does not need to be removed after the concrete is poured, and it can continuously capture the volume deformation and temperature data of the concrete itself.

[0026] Although some preferred embodiments of the present invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of the present invention.

[0027] Obviously, those skilled in the art can make various modifications and variations to this utility model without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this application and their equivalents, this utility model also intends to include these modifications and variations.

Claims

1. A device for measuring stress-free strain in concrete, characterized in that, Includes a strain measurement system, an annular clamp for fixing the stress-free bucket (1), and a telescopic rod welded to the upper part of the annular clamp; The strain measurement system is used to capture the strain signal corresponding to the volume change of concrete under stress-free conditions, and at the same time assists in acquiring ambient temperature data. Annular clamps are used to assist in fixing stress-free buckets (1); The telescopic rod structure is used to fix a stress-free bucket between reinforcing bars (1).

2. The concrete stress-free strain measuring device according to claim 1, characterized in that, The strain measurement system includes a stress-free barrel (1), a horizontal fixing rod (2), a vertical fixing rod (3), a strain gauge (4), a strain plate (5), a guide hole (6), and a wire (7); The stress-free bucket (1) has a foam material layer structure in the inner wall of the bucket, and an asphalt layer is attached to the inner side of the stress-free bucket (1). The stress-free bucket (1) has a frustum shape that is wider at the top and narrower at the bottom, and is designed with a bottom but no lid. A vertical fixing rod (3) is set along the central axis of the stress-free bucket (1), and the vertical fixing rod (3) is connected to the bottom wall inside the stress-free bucket (1). The horizontal fixing rod (2) is set in the middle part of the inner wall of the stress-free bucket (1), and the horizontal fixing rod (2) and the vertical fixing rod (3) are fixedly connected at the intersection. A strain gauge (4) is installed at the intersection, and a strain gauge (5) is bonded to the strain gauge (4). The wire (7) of the strain gauge (5) passes through the guide hole (6) provided on the vertical fixing rod (3) and is connected to the VW-102E full-function reading instrument.

3. The concrete stress-free strain measuring device according to claim 1, characterized in that, The ring clamp includes a semi-circular ring steel sheet (8), a rectangular perforated steel sheet (9), a support bar (10), and a connecting bolt (11). The semi-circular annular steel sheet (8) is set on the outside of the stress-free barrel (1). The two semi-circular annular steel sheets (8) are connected by a rectangular perforated steel sheet (9) to form a ring structure. The ring structure consists of two rings, one above the other, which are laterally welded together by a number of support bars (10). The connecting bolt (11) is used to fix the rectangular perforated steel sheet (9); by tightening the connecting bolt (11), the annular clamp can be pressed against the outer wall of the stress-free barrel (1).

4. The concrete stress-free strain measuring device according to claim 1, characterized in that, The telescopic rod structure is symmetrically installed on both sides of the stress-free barrel (1). The telescopic rod includes a hollow tube (12), an extension tube (13), an annular steel sheet (14), a rectangular perforated steel sheet (15), and a connecting bolt (16). One end of the hollow tube (12) is horizontally welded to the upper ring structure, and the other end is horizontally connected to the elongated tube (13). The length of the elongated tube (13) can be freely adjusted according to actual needs. The hollow tube (12) and the elongated tube (13) are connected by a guide rail at one end. The other end of the elongated tube (13) is connected to an elastic buckle. The elastic buckle includes an annular steel sheet (14), a rectangular perforated steel sheet (15), and a connecting bolt (16). The annular steel sheet (14) is welded to the end of the elongated tube (13). The rectangular perforated steel sheet (15) is welded to the annular steel sheet (14). The connecting bolt (16) achieves the fixing function of the elastic buckle through the rectangular perforated steel sheet (15).

5. The concrete stress-free strain measuring device according to claim 4, characterized in that, The opening of the annular steel sheet (14) is set in the vertical direction, and the stress-free bucket (1) is fixed by clamping the elastic buckle.

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