Prestressed intelligent regulation device and cable force regulation method thereof

Abstract

This application relates to a prestressed intelligent control device and its cable force control method. The floor slab is divided into load-bearing and non-load-bearing zones. The device includes a corrugated pipe embedded in the floor slab and steel strands passing through the corrugated pipe. The portion of the steel strand in the load-bearing zone is bent downwards, while the portion in the non-load-bearing zone is horizontally straight. A first clamp is installed at both ends of the corrugated pipe. A hollow jack and a second clamp are sequentially installed on the side of one of the first clamps away from the corrugated pipe. The first and second clamps are used to clamp the steel strands. The hollow jack is used to push the first and second clamps away from each other. The hollow jack is electrically connected to a controller. A detection component is installed on the second clamp, and the detection component is electrically connected to the controller. This application has the effect of reducing the occurrence of cracking after the floor slab bends upwards.

Description

Technical Field

[0001] This application relates to the field of post-tensioning construction, and in particular to a prestressed intelligent control device and its cable force control method. Background Technology

[0002] In large-span floor slabs, applying prestress to the floor slab can reduce the likelihood of the floor slab bending and breaking downwards when subjected to heavy loads.

[0003] Currently, a prestressing control device is disclosed in related technology, including a corrugated pipe embedded in a floor slab and steel strands passing through the corrugated pipe. The portions of the steel strands and the corrugated pipe located inside the floor slab are bent downwards. A first clamp is installed at both ends of the corrugated pipe. A hollow jack and a second clamp are sequentially arranged on the side of one of the first clamps away from the corrugated pipe. The first and second clamps are used to hold the steel strands, and the hollow jack is used to push the first and second clamps away from each other. When the hollow jack is activated, it pulls the steel strands through the second clamp, thereby straightening the steel strands. The straightening of the steel strands applies an upward force to the floor slab, thereby reducing the likelihood of the floor slab bending and breaking downwards under heavy pressure. When the steel strands are pulled straight, the first clamp releases the steel strands, and the second clamp clamps them. After tensioning is stopped and the hollow jack is removed from between the first and second clamps, the first clamp will clamp the steel strand, thereby limiting the retraction of the steel strand.

[0004] Regarding the aforementioned technologies, the inventors believe that some areas of the floor slab may be used for planting flowers and plants, or for placing heavy objects such as tables, beds, and refrigerators, while other areas may only be used for pedestrian traffic and not for placing heavy objects. Applying prestress to areas of the floor slab where no heavy objects are placed may cause the floor to bend upwards and crack. Summary of the Invention

[0005] To reduce the occurrence of cracks after the floor slab bends upward, this application provides a prestressed intelligent control device and its cable force control method.

[0006] This application provides a prestressed intelligent control device and its cable force control method, which adopts the following technical solution:

[0007] A prestressed intelligent control device includes a floor slab divided into load-bearing and non-load-bearing zones. The device comprises a corrugated pipe embedded in the floor slab and steel strands passing through the corrugated pipe. The portion of the steel strand in the load-bearing zone is bent downwards, forming a curved section. The portion of the steel strand in the non-load-bearing zone is horizontally straight, forming a straight section. A first clamp is installed at both ends of the corrugated pipe. A hollow jack and a second clamp are sequentially installed on the side of the first clamp away from the corrugated pipe. The first and second clamps are used to clamp the steel strands. The hollow jack is used to push the first and second clamps away from each other. The hollow jack is electrically connected to a controller. A detection component is installed on the second clamp and electrically connected to the controller. The detection component generates a detection signal based on the distance between the second clamp and the perimeter of the floor slab, and the tension force exerted by the hollow jack on the steel strand, and sends this signal to the controller. The controller controls the hollow jack to tension the steel strands based on the detection signal.

[0008] By adopting the above technical solution, the bent section of the steel strand is located in the load-bearing area of ​​the floor slab. After tensioning the steel strand, the steel strand applies prestress to the load-bearing area of ​​the floor slab, thereby reducing the likelihood of the floor slab bending downwards and breaking under the pressure of heavy objects. The straight section of the steel strand is located in the non-load-bearing area, thereby reducing the likelihood of the floor slab bending upwards and breaking under the upward prestress.

[0009] Simultaneously, during the tensioning of the steel strands, the detection component sends detection information to the controller. Based on this information, the controller calculates the tension force applied to the steel strands by the hollow jacks and the actual elongation of the steel strands. Once the tension force applied to the steel strands by the hollow jacks reaches its maximum, the controller closes the hollow jacks, thus stopping the tensioning process. The error between the theoretical and actual elongation of the steel strands is then compared. This error helps determine whether the prestress applied to the floor slab by the steel strands meets the design requirements.

[0010] Optionally, the detection component includes a distance sensor and a pressure sensor, both of which are electrically connected to the controller and mounted on the second clamp. The distance sensor generates a distance signal based on the distance between the second clamp and the periphery of the floor slab and sends it to the controller. The pressure sensor generates a pressure signal based on the pressure between the hollow jack and the second clamp and sends it to the controller. The controller controls the tensioning of the hollow jack based on the distance signal and the pressure signal.

[0011] By adopting the above technical solution, when the hollow jack is used to tension the steel strand, the hollow jack compresses the pressure sensor. The pressure sensor generates a pressure signal based on the pressure applied by the hollow jack and sends it to the controller. The controller then obtains the tension force applied to the steel strand by the hollow jack based on the pressure signal.

[0012] When the hollow jack is used to tension the steel strand, the second clamp moves away from the first clamp. A distance sensor detects the distance between the second clamp and the perimeter of the floor slab and sends this information to the controller. The controller then calculates the actual tension length of the steel strand based on the difference between the initial untensioned distance and the tensioned distance of the second clamp.

[0013] Optionally, the location of the second clamp on the steel strand is the tensioning point, and the location of the first clamp on the end of the steel strand away from the second clamp is the fixing point. It also includes a reader installed on the top side of the floor slab. RFID tags are installed at both ends of the steel strand at the tensioning point, the fixing point, and the bending section. The reader is electrically connected to the controller. The reader is used to read the position of the RFID tag to form a position signal and send it to the controller. The controller is used to determine whether there is a tensioning fault in the steel strand based on the position signal.

[0014] By adopting the above technical solution, the distance between adjacent RFID tags changes during the tensioning of the steel strand. The reader reads the position of each RFID tag and sends it to the controller. The controller compares the actual and theoretical positions of the RFID tags to determine if there are any sections of the steel strand stuck inside the corrugated pipe that cannot be stretched, thus ensuring that all bending sections of the steel strand are stretched.

[0015] Optionally, the RFID tag is fixedly mounted with an installation ring, which is rotatably sleeved on the steel strand. The RFID tag is located below the steel strand. A limit cover is provided on the top side of the installation ring, and the limit cover is fixedly mounted on the top side of the steel strand away from the RFID tag. The top side of the installation ring is located inside the limit cover. The limit cover is used to restrict the installation ring from sliding along the length direction of the steel strand. Limit blocks are fixedly mounted on both sides of the RFID tag located inside the corrugated pipe, and the limit blocks abut against the inner wall of the corrugated pipe.

[0016] By employing the above technical solution, the RFID tag is positioned below the steel strand as it enters the corrugated pipe. If the steel strand is rotated during its insertion, the RFID tag is pressed against the inner wall of the corrugated pipe by a limiting block, thus keeping the RFID tag below the steel strand.

[0017] Optionally, a cable tension control method includes the following control methods before tensioning:

[0018] A three-dimensional model is established, which includes a floor slab and corrugated pipes and steel strands embedded in the floor slab. The floor slab is divided into load-bearing and non-load-bearing areas.

[0019] Obtain downward displacement information, wherein the downward displacement information is the downward displacement distance of the midpoint of the downwardly bent portion of the steel strand;

[0020] In the 3D model, the portion of the steel strand located in the load-bearing area bends downwards based on the downward displacement information;

[0021] Set the tensioning point and fixing point for each steel strand in the 3D model;

[0022] Calculate the first length M1 of each curved segment and straight segment between the tensioning point and the fixing point.

[0023] By adopting the above technical solution, RFID tags are installed at the tensioning point, fixing point, and both ends of the bending section of the steel strand. The first length M1 facilitates the determination of the positions of both ends of the bending section on the steel strand, thereby facilitating the installation of the RFID tags on the steel strand.

[0024] Optionally, after calculating the first length M1 of each curved and straight segment between the tensioning point and the fixing point, the following steps are also included:

[0025] Acquire first location information and second location information. The first location information is the position of both ends of the curved section on the three-dimensional model, as well as the positions of the tensioning point and the fixing point. The second location information is the position of each RFID tag.

[0026] Based on the first and second location information, deviation information is obtained, wherein the deviation information is the distance between the two ends of the bending section of the steel strand, the fixing point and the tensioning point on the three-dimensional model and the corresponding RFID tag.

[0027] Obtain the deviation threshold, which is a preset distance;

[0028] Determine whether the deviation information is greater than the deviation threshold; if so, remind the operator that the steel strand is misplaced and return to the execution steps to obtain the first position information and the second position information; if not, remind the operator that the steel strand is placed accurately.

[0029] By employing the above technical solution, after the steel strand is threaded into the corrugated pipe, the actual position of the RFID tag is compared with its position on the 3D model. If the deviation between the actual position of the RFID tag and its position on the 3D model is less than a deviation threshold, the actual position of the RFID tag is aligned with its position on the 3D model. If the deviation is greater than the deviation threshold, the actual position of the RFID tag is misaligned with its position on the 3D model. Then, the construction workers pull the steel strand inside the corrugated pipe until the actual position of the RFID tag is aligned with its position on the 3D model, thus ensuring that RFID tags are attached to both ends of the bent section of the steel strand.

[0030] Optionally, the following control methods may be used during tensioning:

[0031] Obtain the first tension N1 and the second tension N2, where the first tension N1 is the maximum tension of the steel strand and the second tension N2 is the current tension.

[0032] The theoretical elongation L1 of each bending and straight segment between the fixed point and the tensioning point of the steel strand is obtained based on the second tension N2.

[0033] The total theoretical elongation L2 is formed by summing the theoretical elongation L1 of each segment;

[0034] Obtain the first total actual elongation L3, which is the actual elongation of the first steel strand under the tension force N2 of the second tension force.

[0035] Obtain a first error threshold K1, where the first error threshold K1 is the percentage of error allowed when the second tension N2 is applied;

[0036] Determine whether |L2-L3|÷L2≥K1 is true. If yes, stop tensioning and issue a tensioning fault warning. If no, determine whether the second tension N2 is equal to the first tension N1.

[0037] When determining whether the second tension N2 is equal to the first tension N1, if yes, the tensioning stops; otherwise, it returns to retrieve the first tension N1 and the second tension N2.

[0038] By adopting the above technical solution, during the tensioning process of the steel strands, if the deviation between the first total actual elongation L3 and the total theoretical elongation L2 exceeds the first error threshold K1, tensioning is stopped. Afterwards, the construction personnel eliminate the cause of the deviation exceeding the first error threshold K1 and then re-tension the strands, thus ensuring that the prestress applied to the floor slab by the steel strands meets the design requirements.

[0039] Optionally, before determining whether the second tension N2 is equal to the first tension N1, the following steps are also included:

[0040] Obtain third location information, which is the position of the RFID tag after the steel strand has been tensioned by the second tension N2;

[0041] The second length M2 is obtained based on the third location information, where the second length M2 is the length of the steel strand between two adjacent RFID tags;

[0042] The actual elongation L4 of the segment is obtained based on the difference between the first length M1 and the second length M2;

[0043] Determine whether |L1-L4|÷L1≥K1 holds true for each curved and straight section of the steel strand. If yes, stop tensioning and issue a tensioning fault warning. If no, proceed to determine whether the second tension N2 is greater than or equal to the first tension N1.

[0044] By adopting the above technical solution, the curved and straight sections of the steel strand between the fixed point and the tensioning point may have some large deviations and others small deviations. This could result in situations where the deviation between the first total actual elongation L3 and the total theoretical elongation L2 meets the design requirements. By comparing the deviations between the segmented actual elongation L4 and the segmented theoretical elongation L1, it is easier to ensure that the prestress applied to the floor slab by each segment of the steel strand meets the design requirements. Simultaneously, it facilitates construction personnel in identifying sections of the steel strand that do not meet the design requirements.

[0045] Optionally, obtaining the first error threshold K1 further includes the following steps:

[0046] Obtain a second error threshold K2, which is a preset percentage of error allowed when the first tension force N1 is applied;

[0047] The first error threshold K1 is obtained based on the second error threshold K2, the first tension N1, and the second tension N2. The calculation formula for the first error threshold K1 is: K1 = K2 × N2 ÷ N1.

[0048] By adopting the above technical solution, the ratio of the current tension force to the maximum tension force is obtained by N2÷N1. Then, by K2×N2÷N1, the allowable percentage error when tensioning with the second tension force N2 can be easily obtained.

[0049] Optionally, after determining that the second tension N2 is equal to the first tension N1 and stopping the tensioning, the following steps are also included:

[0050] Obtain the second total actual elongation L5, which is the elongation of the steel strand after the hollow jack releases the tension point;

[0051] Determine whether |L2-L5|÷L2≥K1 is true. If yes, then indicate that the steel strand has retracted; if no, then indicate that the tensioning is complete.

[0052] By adopting the above technical solution, after tensioning is stopped, the actual elongation and theoretical elongation of the steel strand are compared again, thereby reducing the possibility of the steel strand shrinking and causing the prestress applied to the floor slab by the steel strand to not meet the design requirements.

[0053] In summary, this application includes at least one of the following beneficial technical effects:

[0054] By bending the steel strands downwards in the load-bearing area of ​​the floor slab, and then tensioning the steel strands, the steel strands apply upward prestress to the load-bearing area of ​​the floor slab, thereby reducing the prestress applied by the steel strands to the non-load-bearing areas of the floor slab, and thus reducing the occurrence of cracking after the floor slab bends upwards.

[0055] By setting RFID tags on the steel strands, it is easy to compare the theoretical elongation and the actual elongation of the steel strands in segments, which in turn makes it easier to apply prestress to the load-bearing areas of the floor slab. Attached Figure Description

[0056] Figure 1 This is a schematic diagram of the prestressed intelligent control device installed on a floor slab according to an embodiment of this application.

[0057] Figure 2 yes Figure 1 Enlarged view at point A;

[0058] Figure 3 This is a schematic diagram of the structure of the RFID tag and steel strand according to an embodiment of this application;

[0059] Figure 4 This is a flowchart of steps S101-106 in an embodiment of this application;

[0060] Figure 5 This is a flowchart of steps S105-111 in an embodiment of this application;

[0061] Figure 6 This is a flowchart of steps S201-210 in an embodiment of this application;

[0062] Figure 7 This is a flowchart of steps S204, S2051, S2052 and S206 in an embodiment of this application;

[0063] Figure 8 This is a flowchart of steps S210-218 in an embodiment of this application.

[0064] Explanation of reference numerals in the attached drawings: 1. Corrugated pipe; 2. Steel strand; 3. First clamp; 4. Second clamp; 5. Hollow jack; 6. Controller; 7. Detection component; 71. Distance sensor; 72. Pressure sensor; 8. Reader; 9. RFID tag; 10. Mounting ring; 11. Limit block; 12. Limit cover. Detailed Implementation

[0065] The following is in conjunction with the appendix Figure 1-8 This application will be described in further detail.

[0066] This application discloses a prestressed intelligent control device and its cable force control method.

[0067] Reference Figure 1 , Figure 2 A prestressed intelligent control device is applied to prestressing tensioning on floor slabs, comprising a corrugated pipe 1 embedded in the floor slab and steel strands 2 threaded through the corrugated pipe 1. Based on the plan for placing items on the floor slab, the area where heavy objects will be placed is designated as a load-bearing area, and the remaining area of ​​the floor slab is designated as a non-load-bearing area. The portion of the steel strand 2 located in the load-bearing area is bent downwards, forming a curved section. The portion of the steel strand 2 located in the non-load-bearing area is horizontally straight, forming a straight section.

[0068] Reference Figure 1 , Figure 2 Both ends of the corrugated pipe 1 are equipped with first clamps 3. The steel strand 2 passes through the first clamps 3, which are embedded in the side wall of the floor slab. When tensioning the steel strand 2, the first clamps 3 release the steel strand 2, thus facilitating tensioning. After tensioning the steel strand 2 stops, the steel strand 2 will retract. By clamping it with the first clamps 3, the occurrence of the steel strand 2 retracting into the floor slab is reduced.

[0069] Reference Figure 1 , Figure 2 A hollow jack 5 is installed on the side of a first clamp 3 away from the corrugated pipe 1, and a second clamp 4 is installed on the side of the hollow jack 5 away from the first clamp 3. The steel strand 2 passes through the hollow jack 5 and the second clamp 4. The second clamp 4 clamps the steel strand 2, with the hollow jack 5 positioned between the first clamp 3 and the second clamp 4. Then, the hollow jack 5 is activated, pushing the second clamp 4 away from the first clamp 3. The second clamp 4 pulls the steel strand 2, thus facilitating the tensioning of the steel strand 2.

[0070] Reference Figure 1 , Figure 2The hollow jack 5 is electrically connected to the controller 6, and the second clamp 4 is equipped with a detection component 7. The detection component 7 includes a distance sensor 71 and a pressure sensor 72. Both the distance sensor 71 and the pressure sensor 72 are electrically connected to the controller 6. The distance sensor 71 detects the distance from the second clamp 4 to the perimeter of the floor slab, generating a distance signal and sending it to the controller 6. The controller 6 obtains the actual tension length of the steel strand 2 based on the distance difference before and after tensioning the second clamp 4. The pressure sensor 72 is located between the hollow jack 5 and the second clamp 4. When the hollow jack 5 is tensioning, it compresses the pressure sensor 72. The pressure sensor 72 detects the pressure from the hollow jack 5, generating a pressure signal and sending it to the controller 6. The pressure signal and the distance signal together form a detection signal.

[0071] Reference Figure 1 , Figure 2 When tensioning the steel strand 2, a maximum tension force is typically set. This maximum tension force is generally 75% of the tension force that the steel strand 2 can withstand. After the hollow jack 5 reaches the maximum tension force on the steel strand 2, the controller 6 closes the hollow jack 5. Then, the actual tensioned length of the steel strand 2 is compared with the theoretical tensioned length. If the error between the actual and theoretical tensioned lengths is large, the controller 6 alerts the construction personnel to a tensioning malfunction. If the error between the actual and theoretical tensioned lengths is small and meets the design requirements, the tensioning work is completed.

[0072] The second clamp 4 on the steel strand 2 is located at the tensioning point, and the first clamp 3 on the end of the steel strand 2 furthest from the second clamp 4 is located at the fixing point. A reader 8 is installed on the floor slab. RFID tags 9 are installed at both ends of the steel strand 2 at the tensioning point, fixing point, and bending section. The reader 8 is electrically connected to the controller 6. The reader 8 reads the position of the RFID tags 9 to generate a position signal and sends it to the controller 6. The controller 6 uses the position signal to determine if there is a tensioning fault in the steel strand 2. In this embodiment, the corrugated pipe 1 is made of plastic to facilitate signal interaction between the RFID tags 9 and the reader 8. The reader 8 is moved to the location of the RFID tag 9 to read it.

[0073] Based on the positions of the tensioning point, fixing point, and both ends of the bending section on the steel strand 2, RFID tags are installed on the steel strand 2. The steel strand 2 is then threaded through the corrugated pipe 1, ensuring that each end of the tensioning point, fixing point, and bending section on the steel strand 2 has an RFID tag 9. In another embodiment, the RFID tag 9 can be replaced with a UWB tag, and the reader 8 can be replaced with a base station.

[0074] During the tensioning of the steel strand 2, the reader 8 reads the data between two adjacent RFID tags 9 and transmits it to the controller 6. The controller 6 obtains the actual tension length of the steel strand 2 between the two adjacent RFID tags based on the changes in the position of the RFID tags 9. The controller 6 then compares the actual tension length with the theoretical tensioning length, thus facilitating segmental assessment of whether the tension deviation of the steel strand 2 meets the design requirements.

[0075] Reference Figure 2 , Figure 3 An RFID tag 9 is fixedly mounted with an mounting ring 10, which is rotatably fitted onto the steel strand 2. Limiting blocks 11 are fixedly mounted on both sides of the RFID tag 9 inside the corrugated pipe 1, and the limiting blocks 11 abut against the inner wall of the corrugated pipe 1. The RFID tag 9 is located below the steel strand 2, and a limiting cover 12 is provided on the top side of the mounting ring 10. The limiting cover 12 is fixedly mounted on the top side of the steel strand 2 away from the RFID tag 9, and the top side of the mounting ring 10 is located inside the limiting cover 12. The limiting cover 12 is used to restrict the sliding of the mounting ring 10 along the length direction of the steel strand 2.

[0076] When the steel strand 2 is inserted into the corrugated pipe 1, the RFID tag 9 is positioned below the steel strand 2. Then, as the steel strand 2 rotates during its insertion into the corrugated pipe 1, the limiting block 11 engages with the inner wall of the corrugated pipe 1, thus ensuring that the RFID tag 9 remains below the steel strand 2.

[0077] Reference Figure 4 A cable tension control method, applied to a prestressed intelligent control device according to an embodiment of this application, includes the following steps before tensioning:

[0078] S101. Create a 3D model. Then proceed to step S102.

[0079] The three-dimensional model includes a floor slab and corrugated pipe 1 and steel strand 2 embedded in the floor slab, and the floor slab of the three-dimensional model is divided into load-bearing and non-load-bearing areas.

[0080] S102. Obtain the downward movement information. Then proceed to step S103.

[0081] The controller 6 is input with the distance the midpoint of the bent section moves downward when the steel strand 2 bends downward, so that the controller 6 can obtain the downward movement information.

[0082] S103. In the 3D model, the portion of steel strand 2 located in the load-bearing area bends downwards according to the downward movement information. Then, step S104 is executed.

[0083] S104. Set the tensioning point and fixing point for each steel strand 2 in the 3D model. Then proceed to step S105.

[0084] S105. Calculate the first length M1 of each curved segment and straight segment between the tensioning point and the fixing point. Then proceed to step S106.

[0085] The RFID tag 9 is installed at the fixed point, tension point and both ends of the bending section of the steel strand 2. With the first length M1, it is convenient to determine the position of the RFID tag 9 on the steel strand 2 when the steel strand 2 is not inserted into the corrugated pipe 1, and thus it is convenient to install the RFID tag 9 on the steel strand 2.

[0086] S106. Obtain the first position information and the second position information. Then proceed to step S107.

[0087] The controller 6 generates first position information based on the spatial coordinates of the two ends of the curved section, the tensioning point, and the fixing point on the 3D model. The reader 8 reads the position of the RFID tag 9 and sends it to the controller 6, thereby enabling the controller 6 to obtain second position information.

[0088] Reference Figure 5 S107. Obtain the deviation threshold. Then proceed to step S108.

[0089] The deviation threshold is a preset distance.

[0090] S108. Obtain deviation information based on the first position information and the second position information. Then proceed to step S109.

[0091] The controller 6 inputs the second position information into the three-dimensional model, and then calculates the distance between the two ends of the bending section of the steel strand 2, the fixed point and the tensioning point in the three-dimensional model and the corresponding RFID tag 9, so that the controller 6 can obtain the deviation information.

[0092] S109. Determine whether the deviation information is greater than the deviation threshold; if yes, proceed to step S110; if no, proceed to step S111.

[0093] S110. Remind the steel strand 2 that there is a deviation in its layout, then return to step S106.

[0094] S111, reminding you to lay the steel strand 2 accurately.

[0095] In the 3D model, when the distance between the RFID tags 9 corresponding to the two ends of the curved section, the fixed point, and the tensioning point of the steel strand 2 exceeds the deviation threshold, each RFID tag 9 on the steel strand 2 is not aligned with the fixed point, the tensioning point, and the two ends of the curved section. Afterwards, the construction workers continue to pull the steel strand 2 inside the corrugated pipe 1, while the controller 6 re-acquires the first position information and compares it with the second position. After each RFID tag 9 on the steel strand 2 is aligned with the fixed point, the tensioning point, and the two ends of the curved section, the controller 6 reminds the steel strand 2 to be laid accurately, thus facilitating the alignment of each RFID tag 9 with the fixed point, the tensioning point, and the two ends of the curved section after the steel strand 2 enters the corrugated pipe 1.

[0096] Reference Figure 6 The tensioning process includes the following steps:

[0097] S201. Obtain the first tension N1 and the second tension N2. Then proceed to step S202.

[0098] The first tension N1 is the maximum tension of the steel strand 2, typically 75% of the tension that the steel strand 2 can bear. When the hollow jack 5 tensions the steel strand 2, it compresses the pressure sensor 72, which generates a pressure signal and sends it to the controller 6. The controller 6 obtains the current tension of the steel strand 2 based on the pressure signal, thereby acquiring the second tension N2.

[0099] S202. Obtain the segmental theoretical elongation L1 of each curved and straight segment between the fixed point and the tensioning point of the steel strand 2 based on the second tension N2. Then execute step S202.

[0100] According to the calculation formula for the average tension force of prestressed tendons in Appendix F of the "Technical Specification for Construction of Highway Bridges and Culverts" (JTJ-041-2000), the average tension force of each curved and straight segment between the fixing point and the tensioning point of the steel strand 2 is calculated. Then, according to the calculation formula for the theoretical elongation of prestressed tendons in the "Technical Specification for Construction of Highway Bridges and Culverts" (JTJ-041-2000), the theoretical elongation of the prestressed tendons is calculated. The basic information such as the elastic modulus and cross-sectional area of ​​the steel strand 2, and the type of corrugated pipe 1 are pre-entered into the controller 6. Then, the controller 6 calculates the tangent angle of the curved segment based on the angle of the curved segment on the three-dimensional model, thus meeting the data required for calculating the segmented theoretical elongation L1.

[0101] S203. The total theoretical elongation L2 is formed by summing the theoretical elongation L1 of each segment. Then, proceed to step S204.

[0102] The total theoretical elongation L2 is the theoretical elongation of the steel strand 2 between the fixed point and the tensioning point.

[0103] S204. Obtain the first total actual elongation L3. Then proceed to step S205.

[0104] After the hollow jack 5 tensions the steel strand 2 with a second tension force N2, the distance sensor 71 detects the distance from the second clamp 4 to the perimeter of the floor slab and sends it to the controller 6. The controller 6 generates a first total actual elongation L3 based on the difference between the distance detected by the distance sensor 71 when the strand is not tensioned and the distance detected when tensioned with the second tension force N2.

[0105] S205. Obtain the first error threshold K1. Then proceed to step S206.

[0106] The first error threshold K1 is the percentage of error allowed when the second tension force N2 is applied.

[0107] Step S205 includes the following steps:

[0108] Reference Figure 7 S2051. Obtain the second error threshold K2. Then proceed to step S2052.

[0109] The second error threshold K2 is the percentage of error allowed when the first tension force N1 is applied. The second error threshold K2 is generally 6%.

[0110] S2052. Obtain the first error threshold K1 based on the second error threshold K2, the first tension N1, and the second tension N2. Then proceed to step S206.

[0111] The formula for calculating the first error threshold K1 is: K1 = K2 × N2 ÷ N1. The tension force of the hollow jack 5 on the steel strand 2 gradually increases to the first tension force N1. The allowable error of the hollow jack 5 under different tension forces is obtained by K2 × N2 ÷ N1.

[0112] Reference Figure 6 S206. Determine whether |L2-L3|÷L2≥K1 is true; if yes, proceed to step S207; if no, proceed to step S208.

[0113] S207. Stop tensioning and issue a warning about tensioning malfunction.

[0114] During the tensioning of steel strand 2 using hollow jack 5, if the deviation between the total theoretical elongation L2 and the first total actual elongation L3 of steel strand 2 exceeds the first error threshold K1, tensioning should be stopped immediately. Afterwards, the construction personnel will troubleshoot the tensioning fault and re-tension the strand.

[0115] S208. Obtain the third location information. Then proceed to step S209.

[0116] After the steel strand 2 is tensioned by the second tension N2, the position of the RFID tag 9 on the steel strand 2 changes. The reader 8 reads the position of the RFID tag 9 and sends it to the controller 6, thereby enabling the controller 6 to obtain the third position information.

[0117] S209. Obtain the second length M2 based on the third position information. Then proceed to step S210.

[0118] The controller 6 inputs the third position information into the three-dimensional model, and then calculates the length of the steel strand 2 between two adjacent RFID tags 9, so that the controller 6 can obtain the length of each bending segment and straight segment of the steel strand 2 between the fixed point and the tensioning point, and thus obtain the second length M2.

[0119] Reference Figure 8 S210. Obtain the actual elongation L4 of the segment based on the difference between the first length M1 and the second length M2. Then execute step S211.

[0120] The first length M1 of the untensioned curved and straight segments corresponds one-to-one with the second length M2 of the current stretched curved and straight segments. The difference between the first length M1 and the second length M2 facilitates the calculation of the actual elongation L4 of each segment of the steel strand 2, both curved and straight.

[0121] S211. Determine whether |L1-L4|÷L1≥K1 holds true for each curved and straight segment of the steel strand 2. If yes, proceed to step S212; otherwise, proceed to step S213.

[0122] S212. Stop tensioning and issue a warning about tensioning malfunction.

[0123] If there are sections with excessive deviations in the bending and straight sections of the steel strand 2, the controller 6 shuts off the hollow jack 5, thereby stopping the tensioning. After the construction personnel troubleshoot the problem, the tensioning is restarted.

[0124] S213. Determine whether the second tension N2 is greater than or equal to the first tension N1; if yes, proceed to step S214; if no, return to step S201.

[0125] S214. Stop tensioning. Then proceed to step S215.

[0126] By testing the tension of the hollow jack 5, tensioning is stopped in time after the tension of the hollow jack 5 reaches the design requirements, thereby reducing the occurrence of excessive tensioning of the steel strand 2.

[0127] S215. Obtain the second total actual elongation L5. Then proceed to step S216.

[0128] The second total actual elongation L5 is the elongation of the steel strand 2 after the hollow jack 5 releases the tension point.

[0129] S216. Determine whether |L2-L5|÷L2≥K1 is true; if yes, proceed to step S217; if no, proceed to step S218.

[0130] S217, Remind steel strand 2 to retract.

[0131] S218, Remind that tensioning is complete.

[0132] After the tensioning of steel strand 2 is completed and the supporting force of the hollow jack 5 on the second clamp 4 is released, steel strand 2 may partially retract before the first clamp 3 clamps it tightly. By comparing the total theoretical elongation L2 and the second total actual elongation L5 again after the tensioning of steel strand 2 is completed, the possibility of insufficient prestress applied to the floor slab due to the retraction of steel strand 2 is reduced.

[0133] The implementation principle of the prestressed intelligent control device and its cable force control method in this application embodiment is as follows: the steel strand 2 is bent downward in the load-bearing area of ​​the floor slab. After tensioning the steel strand 2, the steel strand 2 applies prestress to the load-bearing area of ​​the floor slab, thereby reducing the prestress of the steel strand 2 on the non-load-bearing area of ​​the floor slab, and thus reducing the occurrence of cracking after the floor slab bends upward.

[0134] The above are all preferred embodiments of this application and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A prestressed intelligent control device, wherein the floor slab is divided into load-bearing and non-load-bearing zones, characterized in that: The system includes a corrugated pipe (1) embedded in the floor slab and steel strands (2) passing through the corrugated pipe (1). The portion of the steel strands (2) located in the load-bearing area is bent downwards, forming a curved section. The portion of the steel strands (2) located in the non-load-bearing area is horizontally straight, forming a straight section. Both ends of the corrugated pipe (1) are equipped with first clamps (3). A hollow jack (5) and a second clamp (4) are sequentially arranged on the side of the first clamp (3) away from the corrugated pipe (1). The first clamp (3) and the second clamp (5)... 4) Used to clamp the steel strand (2), the hollow jack (5) is used to push the first clamp (3) and the second clamp (4) away from each other, the hollow jack (5) is electrically connected to the controller (6), the second clamp (4) is equipped with a detection component (7), the detection component (7) is electrically connected to the controller (6), the detection component (7) is used to generate a detection signal based on the distance between the second clamp (4) and the periphery of the floor slab, and the tension force of the hollow jack (5) on the steel strand (2) and send it to the controller (6), the controller (6) is used to control the hollow jack (5) to tension according to the detection signal.

2. The prestressed intelligent control device according to claim 1, characterized in that: The detection component (7) includes a distance sensor (71) and a pressure sensor (72). Both the distance sensor (71) and the pressure sensor (72) are electrically connected to the controller (6). Both the distance sensor (71) and the pressure sensor (72) are installed on the second clamp (4). The distance sensor (71) is used to generate a distance signal based on the distance between the second clamp (4) and the periphery of the floor slab and send it to the controller (6). The pressure sensor (72) is used to generate a pressure signal based on the pressure between the hollow jack (5) and the second clamp (4) and send it to the controller (6). The controller (6) is used to control the tensioning of the hollow jack (5) based on the distance signal and the pressure signal.

3. The intelligent prestressing control device according to claim 1, characterized in that: The position of the second clamp (4) on the steel strand (2) is the tensioning point, and the position of the first clamp (3) on the end of the steel strand (2) away from the second clamp (4) is the fixing point. It also includes a reader (8) set on the top side of the floor slab. The steel strand (2) is equipped with RFID tags (9) at both ends of the tensioning point, the fixing point and the bending section. The reader (8) is electrically connected to the controller (6). The reader (8) is used to read the position of the RFID tag (9) to form a position signal and send it to the controller (6). The controller (6) is used to determine whether the steel strand (2) has a tensioning fault based on the position signal.

4. The intelligent prestressing control device according to claim 3, characterized in that: The RFID tag (9) is fixedly mounted with an installation ring (10), which is rotatably sleeved on the steel strand (2). The RFID tag (9) is located below the steel strand (2). A limit cover (12) is provided on the top side of the installation ring (10). The limit cover (12) is fixedly mounted on the top side of the steel strand (2) away from the RFID tag (9). The top side of the installation ring (10) is located inside the limit cover (12). The limit cover (12) is used to restrict the installation ring (10) from sliding along the length direction of the steel strand (2). Limit blocks (11) are fixedly mounted on both sides of the RFID tag (9) located inside the corrugated pipe (1). The limit blocks (11) abut against the inner wall of the corrugated pipe (1).

5. A cable force control method, applied to the prestressed intelligent control device according to claim 3, characterized in that, Before tensioning, the following control methods are used: A three-dimensional model is established, which includes a floor slab and corrugated pipes (1) and steel strands (2) embedded in the floor slab. The floor slab is divided into load-bearing and non-load-bearing areas; Downward displacement information is obtained, which is the downward displacement distance of the midpoint of the downward bending part of the steel strand (2); The part of the steel strand (2) in the three-dimensional model located in the load-bearing area bends downward according to the downward displacement information; The tensioning point and fixing point of each steel strand (2) in the three-dimensional model are set; The first length M1 of each bending segment and straight segment between the tensioning point and the fixing point of the steel strand (2) in the three-dimensional model is calculated.

6. The cable force control method according to claim 5, characterized in that, After calculating the first length M1 of each curved segment and straight segment between the tensioning point and the fixed point, the following steps are also included: obtaining first position information and second position information, wherein the first position information is the position of the two ends of the curved segment on the three-dimensional model, as well as the position of the tensioning point and the fixed point, and the second position information is the position of each RFID tag (9); obtaining deviation information based on the first position information and the second position information, wherein the deviation information is the distance between the two ends of the curved segment, the fixed point and the tensioning point of the steel strand (2) on the three-dimensional model and the corresponding RFID tag (9); obtaining a deviation threshold, wherein the deviation threshold is a preset distance; determining whether the deviation information is greater than the deviation threshold; if so, then reminding that the steel strand (2) is laid out with deviation, and returning to the execution steps of obtaining the first position information and obtaining the second position information; if not, then reminding that the steel strand (2) is laid out accurately.

7. The cable tension control method according to claim 6, characterized in that, The tensioning process includes the following control methods: obtaining a first tension N1 and a second tension N2, where the first tension N1 is the maximum tension of the steel strand (2) and the second tension N2 is the current tension; obtaining the segmented theoretical elongation L1 of each curved segment and straight segment between the fixed point and the tensioning point of the steel strand (2) based on the second tension N2; forming the total theoretical elongation L2 based on the sum of the segmented theoretical elongation L1; obtaining the first total actual elongation L3, where the first total actual elongation L3 is the actual elongation of the first steel strand (2) under the tension of the second tension N2; Obtain the first error threshold K1, which is the percentage of error allowed when the second tension N2 is tensioned; Determine whether |L2-L3| ÷ L2 ≥ K1 is true. If yes, stop tensioning and issue a tensioning fault warning; if no, determine whether the second tension N2 is equal to the first tension N1; When determining whether the second tension N2 is equal to the first tension N1, if yes, stop tensioning; if no, return to obtain the first tension N1 and the second tension N2.

8. The cable force control method according to claim 7, characterized in that, Before determining whether the second tension N2 is equal to the first tension N1, the following steps are also included: obtaining third position information, which is the position of the RFID tag (9) after the steel strand (2) is tensioned by the second tension N2; obtaining the second length M2 according to the third position information, which is the length of the steel strand (2) between two adjacent RFID tags (9); obtaining the segmental actual elongation L4 according to the difference between the first length M1 and the second length M2; determining whether |L1-L4|÷L1≥K1 of each curved segment and straight segment of the steel strand (2) is true; if yes, then stop tensioning and remind of tensioning failure; if no, then perform the determination of whether the second tension N2 is greater than or equal to the first tension N1.

9. The cable tension control method according to claim 7, characterized in that: Obtaining the first error threshold K1 further includes the following steps: obtaining a second error threshold K2, wherein the second error threshold K2 is a preset percentage of error allowed when the first tension N1 is tensioned; obtaining the first error threshold K1 based on the second error threshold K2, the first tension N1, and the second tension N2, wherein the calculation formula for the first error threshold K1 is: K1=K2×N2÷N1.

10. A cable tension control method according to claim 9, characterized in that: After determining that the second tension N2 is equal to the first tension N1 and stopping the tensioning, the following steps are also included: Obtain the second total actual elongation L5, which is the elongation of the steel strand (2) after the hollow jack (5) releases the tensioning point; Determine whether |L2-L5|÷L2≥K1 is true. If yes, then remind the steel strand (2) to retract; if no, then remind the tensioning to be completed.

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