A flexible tie rod cable force monitoring device and monitoring method

Abstract

The application provides a flexible tie rod cable force monitoring device and a monitoring method, and relates to the technical field of bridge engineering. The device comprises a tie rod support frame, a wedge block seat, a wedge block, a top plate and a nylon pad. The tie rod support frame is pre-buried on a bridge pier. The wedge block seat is provided with a sliding groove. The wedge block is located in the sliding groove. The top plate is placed on the wedge block. The nylon pad is placed on the top plate. A screw hole is formed in the wedge block. A transverse screw passes through the screw hole and is connected with a transverse nut. A pressure sensor is arranged between the wedge block and the transverse nut. The tie rod support frame is pre-buried on the bridge pier, and the tie rod is placed on the nylon pad. The force transmission structure composed of the wedge block, the top plate and the wedge block seat is used to transmit the vertical component force of the tie rod to the transverse screw. The axial force of the transverse screw is monitored through the pressure sensor. The mechanical relationship is established according to the wedge block inclined angle, the friction coefficient and other parameters. The actual cable force in the bridge operation period is calculated reversely according to the sensor reading. The continuous and direct monitoring of the tie rod cable force is realized. The structure is simple and reliable.

Description

Technical Field

[0001] This invention relates to the field of bridge engineering technology, and in particular to a flexible tie rod cable force monitoring device and monitoring method. Background Technology

[0002] As the core load-bearing component of tied-arch bridges, the accurate monitoring of the cable force of the tie rods is crucial to ensuring the safety and durability of the bridge structure. Currently, common methods for monitoring tie rod cable force mainly rely on periodic manual inspection or the installation of specialized sensors. However, these methods often suffer from problems such as complex installation, poor long-term stability, and difficulty in achieving real-time continuous monitoring. In particular, during operation, the dynamic changes in tie rod cable force are difficult to capture accurately.

[0003] Traditional tie rod anchoring devices mostly use fixed support structures, which do not have integrated monitoring functions. The acquisition of cable force usually requires additional tensioning equipment or disassembly and testing, which is cumbersome and inefficient, and cannot meet the requirements of modern bridge health monitoring systems for real-time and continuous data.

[0004] Therefore, there is an urgent need for a flexible tie rod cable force monitoring device and method that can achieve long-term stable and real-time monitoring to solve the problems of low efficiency, poor real-time performance, and difficulty in long-term reliable operation of traditional cable force monitoring methods. Summary of the Invention

[0005] Purpose of the invention: To address the problems of existing tie rod cable force monitoring methods, such as complex installation, poor long-term stability, difficulty in achieving real-time continuous monitoring, lack of integrated monitoring functions in traditional anchoring devices, and cumbersome and inefficient cable force acquisition process, this invention proposes a flexible tie rod cable force monitoring device and method to achieve long-term, stable, real-time, and direct monitoring of tie rod cable force, effectively ensuring the safety and durability of bridge structures.

[0006] To achieve the aforementioned technical objectives, a first aspect of the present invention discloses a flexible tie rod tension monitoring device. This device includes a tie rod support frame, a wedge seat, a wedge, a top plate, a nylon pad, a transverse screw, a transverse nut, and a pressure sensor. The tie rod support frame is pre-embedded in the bridge pier. The wedge seat is fixed to the tie rod support frame and has a sliding groove. The wedge is placed in the sliding groove. The top plate is placed on the wedge, with its inclined surface angle matching that of the wedge. The nylon pad is fixed to the top plate by pad bolts and pad nuts to support the tie rod. A screw hole is formed in the wedge, through which the transverse screw passes and connects to the transverse nut. A pressure sensor is installed between the wedge and the transverse nut. The top plate and the wedge seat are fixed to the tie rod support frame by limiting bolts, forming a transverse limit.

[0007] Furthermore, the tie rod support frame is welded from steel plates and pre-embedded inside the bridge pier.

[0008] Furthermore, the groove on the wedge block seat is used to constrain the movement direction of the wedge block.

[0009] Furthermore, the nylon pad directly supports the tie rod, transmitting the vertical component of the tie rod to the top plate.

[0010] Furthermore, the top plate and the wedge block are in contact via inclined surfaces, which decomposes the vertical force.

[0011] Furthermore, the transverse screw, transverse nut, and pressure sensor constitute a force transmission and measurement unit for monitoring the axial force on the transverse screw.

[0012] Based on the monitoring device disclosed in the first aspect, the second aspect of the present invention discloses a method for monitoring the force of a flexible tie rod, the specific process of which is as follows:

[0013] The tie rod is placed on the nylon pad, and the vertical force w on the nylon pad is calculated when the tie rod is tensioned to the design cable force P. Force analysis is performed on the top plate and wedge in both the horizontal and vertical directions. Establish the correspondence between the tie rod cable force P and the axial force N on the transverse screw; The real-time axial force of the transverse screw is obtained by a pressure sensor. Based on the correspondence between the tie rod cable force P and the axial force N on the transverse screw, the real-time cable force of the tie rod is calculated. .

[0014] Furthermore, the vertical force w acting on the nylon pad is calculated according to the following formula:

[0015] In the formula, Let P be the tension force on the tie rod and its vertical component P. The angle between them.

[0016] Furthermore, a force analysis of the top plate in the horizontal and vertical directions is performed, satisfying the following relationship:

[0017]

[0018]

[0019]

[0020] In the formula, This refers to the supporting force of the wedge block on the top plate. The angle of the wedge's inclined plane; This refers to the frictional force between the inclined surface of the wedge and the top plate. It is the coefficient of friction between the wedge-shaped surface of the wedge block and the inclined surface of the top plate.

[0021] Furthermore, the forces acting on the wedge in the horizontal and vertical directions are analyzed, and the following relationship is satisfied:

[0022]

[0023]

[0024]

[0025] In the formula, This refers to the supporting force of the wedge block seat on the wedge block; This refers to the frictional force between the bottom surface of the wedge and the wedge seat. The coefficient of friction is the friction coefficient between the bottom surface of the wedge and the wedge seat.

[0026] Furthermore, the wedge, top plate, and wedge seat are all made of the same type of steel, therefore the coefficient of friction is... Then it can be simplified to:

[0027] The axial force N acting on the transverse screw under the design cable force P satisfies the following relationship:

[0028] In the formula, It is the coefficient of friction between 40Cr steels.

[0029] Furthermore, when the design cable force P changes, the force N on the pressure sensor will also change accordingly. Assume the changed tie rod cable force is... The pressure sensor value after the change is By monitoring the pressure sensor values ​​in real time Calculate the tie rod cable force for:

[0030] Compared with the prior art, the present invention has the following beneficial effects: (1) The device integrates the force transmission structure and monitoring function into one unit. It uses the pre-embedded tie rod support frame as the installation foundation. The structure is simple and reliable, and it is easy to implement in bridge construction or on existing bridges.

[0031] (2) By directly monitoring the transverse screw axial force related to the tie rod force through pressure sensors, long-term, continuous and real-time monitoring of the tie rod force during the bridge operation period can be achieved.

[0032] (3) Based on the mechanical principle of the wedge mechanism, a clear cable force conversion formula is established. The actual cable force can be directly and accurately calculated by reading the sensor, thus avoiding the error of indirect measurement.

[0033] (4) The device has a stable structure and the sensors are easy to maintain or replace, making it suitable for various bridge projects that require monitoring of the force of flexible tie rods. Attached Figure Description

[0034] Figure 1 This is a schematic diagram showing the relative position of the flexible tie rod cable force monitoring device proposed in this invention to the main bridge structure.

[0035] Figure 2 This is a schematic diagram showing the relative position of the flexible tie rod force monitoring device and the tie rod proposed in this invention.

[0036] Figure 3 This is a schematic diagram of the overall structure of the flexible tie rod cable force monitoring device proposed in this invention.

[0037] Figure 4 This is a structural disassembly diagram of the flexible tie rod cable force monitoring device proposed in this invention.

[0038] Figure 5 This is a force analysis diagram of the nylon pad after the tie rod is tensioned.

[0039] Figure 6 This is a schematic diagram of the stress analysis of the top plate.

[0040] Figure 7 This is a schematic diagram of the force analysis of the wedge block.

[0041] The attached figures are labeled as follows: 1. Tie rod support frame; 2. Wedge block seat; 3. Top plate; 4. Wedge block; 5. Nylon pad block; 6. Transverse screw; 7. Transverse nut; 8. Pressure sensor; 9. Limit bolt; 10. Pad bolt; 11. Pad nut. Detailed Implementation

[0042] In the following description, numerous specific details are set forth in order to provide a more thorough understanding of the invention. However, it will be apparent to those skilled in the art that the invention can be practiced without one or more of these details. In other instances, certain technical features well-known in the art have not been described in order to avoid obscuring the invention.

[0043] Example 1 This embodiment discloses a flexible tie rod tension monitoring device, comprising a tie rod support frame 1, a wedge seat 2, a wedge 4, a top plate 3, and a nylon pad 5. The tie rod support frame 1 is pre-embedded in the pier. The wedge seat 2 has a groove, the wedge 4 is located in the groove, the top plate 3 is placed on the wedge 4, and the nylon pad 5 is placed on the top plate 3. The top plate 3 and the wedge seat 2 are fixed to the tie rod support frame 1 by limiting bolts 9, forming a lateral limit. The nylon pad 5 is fixed to the top plate 3 by pad bolts 10 and pad nuts 11. The wedge 4 has a screw hole, a lateral screw 6 passes through the screw hole and is connected to a lateral nut 7, and a pressure sensor 8 is installed between the wedge 4 and the lateral nut 7.

[0044] In this embodiment, the tie rod support frame 1 is welded from steel plates, and bolt holes are opened at the installation positions corresponding to the wedge block seats. The tie rod support frame 1 is pre-embedded inside the pier, such as... Figure 1 As shown.

[0045] In this embodiment, the wedge block seat 2 is provided with a sliding groove and bolt holes are opened at the four corners.

[0046] In this embodiment, the wedge 4 is placed in the groove of the wedge seat 2, and the wedge 4 has a screw hole.

[0047] In this embodiment, the inclination angle of the inclined surface of the top plate 3 is equal to the inclination angle of the inclined surface of the wedge block 4, and bolt holes are opened at the four corners of the top plate 3. The top plate 3 is placed on the wedge block 4.

[0048] In this embodiment, the nylon pad 5 has bolt holes at its four corners and is fixed to the top plate 3 by pad bolts 10 and pad nuts 11.

[0049] In this embodiment, the top plate 3 and the wedge block seat 2 are fixed to the tie rod support frame 1 by the limiting bolts 9 to form a lateral limit.

[0050] In this embodiment, the transverse screw 6 passes through the screw hole on the wedge block 4 and is connected to the transverse nut 7. A pressure sensor 8 is set between the wedge block 4 and the transverse nut 7 to monitor the axial force N on the transverse screw 6.

[0051] Example 2 Based on the monitoring device disclosed in Example 1, this example further discloses its monitoring method.

[0052] In this embodiment, the tie rod is placed on the nylon pad 5, such as Figure 5 As shown. When the tie rod is tensioned to the design cable force P, the vertical force w on the nylon pad 5 is:

[0053] Force analysis of the top plate 3 in the horizontal and vertical directions is performed, such as... Figure 6 As shown, we can obtain:

[0054]

[0055]

[0056] Combining formulas (2), (3), and (4), we can obtain:

[0057] Depend on Figure 7 Force analysis of wedge 4 in the horizontal and vertical directions yields the following results:

[0058]

[0059]

[0060] Combining formulas (6), (7), and (8), we can obtain:

[0061] Substituting formula (5) into (9), we get:

[0062] Since wedge 4, top plate 3, and wedge seat 2 are made of the same type of steel, the coefficient of friction is mainly determined by the material. = Formula (10) can be simplified to:

[0063] In the formula, This represents the supporting force of wedge 4 on top plate 3. The supporting force of wedge block seat 2 on wedge block 4; For vertical loads; The angle of the inclined plane of wedge 4; The frictional force between the inclined surface of wedge 4 and top plate 3; The frictional force between the bottom surface of wedge 4 and wedge seat 2; The coefficient of friction between the wedge-shaped surface of wedge 4 and the inclined surface of top plate 3; The coefficient of friction between the bottom surface of wedge 4 and wedge seat 2; The coefficient of friction between 40Cr steels; The force is the axial force of the transverse screw 6, which is the reading of the pressure sensor 8.

[0064] Combining formulas (1) and (11), the axial force N of the transverse screw 6 under the design cable force is:

[0065] When the initial cable force P changes, the force N on the pressure sensor 8 will also change accordingly. Assume the changed tie rod cable force is... The pressure sensor value after the change is Then we have:

[0066] The tie rod force can be calculated by monitoring the pressure sensor value N' in real time and substituting it into formula (13). for:

[0067] Example 3 This embodiment discloses the specific on-site construction process.

[0068] I. Installation and Pre-embedding of the Device The tie rod support frame is pre-embedded at the designed location on the pier to ensure a firm bond with the pier concrete. The wedge block seat is bolted to the tie rod support frame, with the wedge block embedded in the groove of the wedge block seat. The top plate is installed above the wedge block and connected to the wedge block seat via limit bolts, forming a lateral constraint. Nylon pads are fixed to the top plate via pad bolts and pad nuts to support the tie rod.

[0069] II. Tensioning and Force Transfer of Tie Rods The tie rod is placed on the nylon pad and tensioned to the design cable force P. After tensioning, its vertical component w is transmitted to the top plate through the nylon pad. Figure 5 The force is then transmitted to the transverse screw via the inclined plane of the wedge. The formula for calculating the vertical component force w is given in equation (1) above, and will not be elaborated here.

[0070] III. Establishment of Mechanical Relationships and Sensor Calibration Through force analysis of the top plate and wedges ( Figure 6 , Figure 7 ), and establish the mechanical relationship between the vertical load w and the pressure sensor reading N. The wedge slope angle α and the friction coefficient μ are the key parameters. Finally, the relationship between the cable force P and the sensor reading N is derived, namely the above formula (12), which will not be elaborated here.

[0071] IV. Cable Stress Monitoring and Feedback During bridge operation, pressure sensors monitor the axial force N of the transverse bolts in real time, and the actual cable force P of the tie rods is calculated using the above formula. N Data can be transmitted to the monitoring center via wired or wireless means, enabling long-term, continuous, and automated monitoring of tie rod tension.

[0072] V. Maintenance and Calibration Regularly check the wear of the wedges, screws, and sensors, and calibrate the friction coefficient μ on-site when necessary to ensure the accuracy of the monitoring data.

[0073] Example 4 The operating mechanism and calculation process of the disclosed Embodiment 2 can be implemented in hardware, software, firmware, or a combination of these implementation methods. Embodiments of this application can be implemented as computer programs or program code executable on a programmable system, which includes at least one processor, a storage system (including volatile and non-volatile memory and / or storage elements), at least one input device, and at least one output device.

[0074] Program code can be applied to input instructions to execute the functions described in this application and generate output information. The output information can be applied to one or more output devices in a known manner. For the purposes of this application, the processing system includes any system having a processor such as, for example, a Digital Signal Processor (DSP), a microcontroller, an Application Specific Integrated Circuit (ASIC), or a microprocessor.

[0075] The program code can be implemented using a high-level procedural language or an object-oriented programming language to communicate with the processing system. Assembly language or machine language can also be used when needed. In fact, the mechanisms described in this application are not limited to any particular programming language. In either case, the language can be a compiled language or an interpreted language.

[0076] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity, not all possible combinations of the technical features in the above embodiments have been described. However, as long as the combination of these technical features does not contradict each other, it should be considered within the scope of this specification. Although the present invention has been shown and described with reference to specific preferred embodiments, it should not be construed as limiting the invention itself. Various changes in form and detail may be made without departing from the spirit and scope of the invention as defined in the appended claims.

Claims

1. A flexible tie rod cable force monitoring device, characterized in that, include: Tie rod support frame (1), wedge block (4) seat (2), top plate (3), wedge block (4), nylon pad (5); The tie rod support frame (1) is embedded in the bridge pier; the wedge block (4) seat (2) is provided with a sliding groove, the wedge block (4) is located in the sliding groove, the top plate (3) is placed on the wedge block (4), and the nylon pad (5) is fixed on the top plate (3); The top plate (3) and the wedge block (4) seat (2) are fixed on the tie rod support frame (1); the wedge block (4) has a screw hole, the transverse screw (6) passes through the screw hole and is connected to the transverse nut (7), and a pressure sensor (8) is set between the wedge block (4) and the transverse nut (7) to monitor the axial force on the transverse screw (6).

2. The flexible tie rod cable force monitoring device according to claim 1, characterized in that, The tie rod support frame (1) is embedded in the inner side of the pier, is made of steel plate welded together, and has bolt holes at the installation positions corresponding to the wedge block (4) seat (2).

3. The flexible tie rod cable force monitoring device according to claim 1, characterized in that, The inclination angle of the inclined surface of the top plate (3) is equal to the inclination angle of the inclined surface of the wedge block (4), and bolt holes are opened at the four corners of the top plate (3).

4. The flexible tie rod cable force monitoring device according to claim 1, characterized in that, The top plate (3) and wedge block (4) seat (2) are fixed to the tie rod support frame (1) by limiting bolts (9) to form a lateral limit.

5. The monitoring method of the flexible tie rod cable force monitoring device according to any one of claims 1 to 4, characterized in that, Includes the following steps: The tie rod is placed on the nylon pad (5), and the vertical force w on the nylon pad (5) is calculated when the tie rod is tensioned to the design cable force P; Force analysis was performed on the top plate (3) and wedge (4) in the horizontal and vertical directions respectively; Establish the correspondence between the tie rod cable force P and the axial force N on the transverse screw (6); The real-time axial force of the transverse screw (6) is obtained by pressure sensor (8). Based on the correspondence between the tie rod cable force P and the axial force N on the transverse screw (6), the real-time cable force of the tie rod can be calculated. .

6. The monitoring method according to claim 5, characterized in that, The vertical force w acting on the nylon pad (5) is calculated according to the following formula: In the formula, Let the tie rod force P and its vertical component P be... The angle between them.

7. The monitoring method according to claim 5 or 6, characterized in that, The forces acting on the top plate (3) in the horizontal and vertical directions satisfy the following relationship: In the formula, The supporting force of the wedge (4) on the top plate (3); Let be the angle of the inclined plane of the wedge (4); The friction coefficient between the wedge surface of the wedge block (4) and the inclined surface of the top plate (3) is given.

8. The monitoring method according to claim 7, characterized in that, Force analysis of wedge (4) in the horizontal and vertical directions satisfies the following relationship: In the formula, is the coefficient of friction between the bottom surface of the wedge (4) and the seat (2) of the wedge (4); N is the axial force on the transverse screw (6).

9. The monitoring method according to claim 8, characterized in that, The wedge (4), top plate (3), and wedge (4) seat (2) are made of the same type of steel, therefore the coefficient of friction is... Then, simplifying, we get: The relationship between the tie rod cable force P and the axial force N on the transverse screw (6) is as follows: In the formula, It is the coefficient of friction between 40Cr steels.

10. The monitoring method according to claim 9, characterized in that, When the design cable force P changes, the force N on the pressure sensor (8) will also change accordingly, satisfying the following relationship: In the formula, The changed tie rod force; The value of the pressure sensor (8) after the change.

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