Prestress tensioning method for prefabricated rainwater box culvert

Abstract

The invention provides a pre-stress tensioning method for a prefabricated rainwater box culvert. The pre-stress tensioning method comprises the following steps that S1, every two adjacent rainwater box culvert sections are connected through a steel strand; s2, anchorage device gaskets are cleaned and symmetrically installed on the rainwater box culvert sections, and meanwhile the anchorage device gaskets are adjusted so that the ends of the anchorage device gaskets can be arranged in a flush mode; s3, the jack is checked, the jack is installed on a bracket to be tensioned after checking is completed, a symmetrical tensioning mode is adopted during tensioning, a double-control mode is adopted in the tensioning process, the tensioning stress is mainly controlled, the extension value of the reinforcing steel bar is controlled, and mutual checking is conducted; and S4, after tensioning is completed, grouting is conducted through the grouting holes, and anchor sealing of the tensioning box is completed. According to the method, the opposite angles are tensioned at the same time, the tensile stress is mainly controlled, the elongation value of the reinforcing steel bars is controlled, and mutual checking is carried out, so that damage to the bell and spigot and the tensioning box is avoided, and the tensioning quality is guaranteed.

Description

Technical Field

[0001] The invention relates to the technical field of prefabricated structures, and in particular to a prefabricated rainwater box culvert prestressing method. Background Art

[0002] Rainwater box culvert is a type of urban underground pipeline, that is, a space built underground in the city for rainwater discharge, with special inspection wells, which is the "lifeline" for urban flood prevention.

[0003] Nowadays, underground rainwater box culverts are made in two ways: traditional cast-in-place and prefabricated. Compared with traditional cast-in-place, prefabricated rainwater box culverts have the advantages of energy saving, environmental protection, fast and efficient, and good quality. However, when prefabricated rainwater box culverts are segmented, the prestressed tensioning and grouting are prone to incomplete grouting of the channels and loose sealing of the tensioning box anchors, which causes the prestressed steel bars to rust and lose their function, resulting in larger joints between the prefabricated rainwater box culvert segments and increased risk of leakage. Therefore, the prestressed tensioning method of prefabricated rainwater box culverts in the prior art has the disadvantages of incomplete grouting and loose sealing of the anchors. Summary of the invention

[0004] In view of this, the present invention proposes a prefabricated rainwater box culvert prestressing tensioning method, aiming to solve the problem of incomplete grouting in the existing prefabricated rainwater box culvert prestressing tensioning method.

[0005] The present invention proposes a prefabricated rainwater box culvert prestressing method, which comprises the following steps: step S1, connecting two adjacent rainwater box culvert sections by steel strands; step S2, cleaning anchor gaskets and symmetrically installing them on the rainwater box culvert sections, and adjusting the anchor gaskets so that their ends are flush; step S3, calibrating the jacks, and after the calibration, installing the jacks on brackets for tensioning, using a symmetrical tensioning method, and using a dual control method during the tensioning process, mainly controlling the tensioning stress, and auxiliaryly controlling the steel bar elongation value and checking each other; step S4, after the tensioning is completed, grouting is performed through grouting holes to complete the sealing and anchoring of the tensioning box.

[0006] Furthermore, when calibrating the jacks in the above-mentioned prefabricated rainwater box culvert prestressing tensioning method, a standard dynamometer calibration method is adopted.

[0007] Furthermore, in the above-mentioned prefabricated rainwater box culvert prestressing tensioning method, when calibrating the jack, a standard dynamometer calibration method is adopted, specifically: the oil circuit and power supply of the electric oil pump are connected, the jack is supplied with oil, the piston moves up, and the standard dynamometer is pressed; when the dynamometer reaches the preset tonnage, the reading is taken from the oil pressure gauge of the jack; the pressure readings of each tonnage are recalibrated three times, and then the average value of the corresponding readings of the oil pressure gauge at each tonnage is calculated as the pressure gauge reading, and then the oil pressure gauge reading corresponding to the preset tensioning force is calculated based on univariate linear regression.

[0008] Furthermore, in the above-mentioned prefabricated rainwater box culvert prestressing tensioning method, after the jack is installed in place, the tool anchor is installed and space is reserved for removing the anchor gasket, plastic tape is pasted on the smooth surface of the gasket of the tool anchor, and after the tool gasket is installed, it is hammered solid with an iron pipe.

[0009] Furthermore, in the above-mentioned prefabricated rainwater box culvert prestressing tensioning method, two adjacent rainwater box culvert segments are connected by non-bonded prestressed strands.

[0010] Furthermore, in the above-mentioned prefabricated rainwater box culvert prestressing tensioning method, after the tensioning is completed, a fine stone concrete grouting machine is used to perform grouting through the grouting holes.

[0011] Furthermore, in the above-mentioned prefabricated rainwater box culvert prestressing method, during the rainwater box culvert prefabrication process, a steel pipe with a plastic rubber tube is used as a tensioning hole template, and the steel pipe is taken out when the template is removed to form a complete hole with a plastic rubber tube.

[0012] Furthermore, in the above-mentioned prefabricated rainwater box culvert prestressing tensioning method, the plastic rubber tube is taken out before the steel strands are inserted into the prestressed pipe.

[0013] Furthermore, in the above-mentioned prefabricated rainwater box culvert prestressing method, during tensioning, first, the A and B tensioning grooves arranged on the same side are pressurized and tensioned to 70% at the same time, then the C and D tensioning grooves arranged on the other side are pressurized and tensioned to 70% at the same time, and then the A and B tensioning grooves are pressurized and tensioned to 100% at the same time, and finally the C and D tensioning grooves are pressurized and tensioned to 100% at the same time.

[0014] Furthermore, in the above-mentioned prefabricated rainwater box culvert prestressing method, during tensioning, the relative error between the measured elongation value and the theoretical elongation value is controlled within ±6%, and after the tensioning reaches the controlled stress, the load is held for 5 minutes before anchoring.

[0015] The prefabricated rainwater box culvert prestressed tensioning method provided by the present invention performs tensioning diagonally at the same time, mainly controls the tensile stress, supplemented by controlling the elongation value of the steel bars, and checks each other, thereby avoiding damage to the socket and the tensioning box, thereby ensuring the tensioning quality and solving the problem of incomplete grouting in the existing prefabricated rainwater box culvert prestressed tensioning method. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present invention. Moreover, the same reference symbols are used throughout the accompanying drawings to represent the same components. In the accompanying drawings: Figure 1A flowchart of a prefabricated rainwater box culvert prestressing method provided in an embodiment of the present invention; Figure 2 A schematic diagram of the positions of the tensioning holes of the prefabricated rainwater box culvert provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0017] Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present disclosure and to be able to fully convey the scope of the present disclosure to those skilled in the art. It should be noted that, in the absence of conflict, the embodiments of the present invention and the features described in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0018] See also Figure 1 , which is a flowchart of the prestressing method of the prefabricated rainwater box culvert provided by the embodiment of the present invention. As shown in the figure, Step S1, connecting two adjacent rainwater culvert sections through steel strands.

[0019] Specifically, non-bonded prestressed stranded wire, i.e. stranded wire with a straight anti-corrosion plastic sheath, can be used to connect two adjacent rainwater culvert sections through steel stranded wire. In other words, non-bonded prestressed stranded wire is used to connect two adjacent rainwater culvert sections.

[0020] Step S2, clean the anchor gasket and install it symmetrically on the rainwater culvert segment, and adjust the anchor gasket so that its ends are flush.

[0021] Specifically, clean the anchor gasket so that the steel strand can be passed through the corresponding hole of the anchor. Clean the gasket when installing it to prevent mud and sand from affecting the anchoring performance of the anchor. Install it symmetrically on the rainwater culvert segment while keeping the outer end of the anchor gasket flush.

[0022] Step S3, calibrate the jack, and after the calibration is completed, install the jack on the bracket for tensioning. A symmetrical tensioning method is adopted during the tensioning process, and a double control method is adopted during the tensioning process, mainly controlling the tensioning stress and auxiliary controlling the steel bar elongation value and checking each other.

[0023] Specifically, the jack is calibrated and then installed on the bracket for tensioning. Symmetrical tensioning, i.e. diagonal tensioning, is adopted during tensioning. Double control is adopted in the tensioning process and tensioning effect, mainly controlling the tensioning stress and auxiliary controlling the elongation value of the steel bar and checking each other. The relative error between the measured elongation value and the theoretical elongation value is controlled within ±6%. The tensioning force should meet the design requirements. After tensioning reaches the controlled stress, anchor it after holding the load for 5 minutes and fill in the tensioning record in time.

[0024] Step S4, after the tensioning is completed, grouting is performed through the grouting holes to complete the anchoring of the tensioning box.

[0025] Specifically, after the tensioning is completed, a fine stone concrete grouting machine is used to inject grout through the grouting holes to complete the anchor sealing of the tensioning box.

[0026] Furthermore, in the prefabrication process of the rainwater culvert, a steel pipe with a plastic rubber tube is used as a tensioning hole template. When the template is removed, the steel pipe is taken out to form a complete hole. When the steel strand is inserted into the prestressed pipe, the plastic rubber tube is taken out. By providing the plastic rubber tube, the steel strand can be effectively prevented from rubbing and colliding with the concrete during the construction process, and the problem of getting stuck in the pipe and causing splitting and bending can be prevented.

[0027] Furthermore, the jack is calibrated using the standard dynamometer calibration method. The oil circuit and power supply of the electric oil pump are connected, the jack is supplied with oil, the piston moves up, and the standard dynamometer is pressed against it. When the dynamometer reaches a certain tonnage, the reading is immediately taken from the oil pressure gauge of the jack. The pressure readings of each tonnage are recalibrated three times, and then the average value of the corresponding readings of the oil pressure gauge at each tonnage is calculated as the pressure gauge reading. Then, based on the univariate linear regression, the oil pressure gauge reading corresponding to the designed tension force is calculated. After the jack is installed in place, the tool anchor is installed and space is reserved for the removal of the anchor gasket. Plastic tape is pasted on the smooth surface of the gasket of the tool anchor. After the tool gasket is installed, it should be knocked solid with an iron pipe.

[0028] Furthermore, in order to better implement the present invention, Figure 2 As shown, during tensioning, first pressurize and tension the A and B tensioning grooves to 70% at the same time, then pressurize and tension the C and D tensioning grooves to 70% at the same time, then pressurize and tension the A and B tensioning grooves to 100% at the same time, and finally pressurize and tension the C and D tensioning grooves to 100% at the same time.

[0029] Furthermore, the anchor sealing is carried out after the final tensioning is completed, and a fine stone concrete grouting machine is used to inject grout through the grouting holes to complete the anchor sealing of the tensioning box.

[0030] In summary, the prefabricated rainwater box culvert prestressed tensioning method provided in this embodiment performs tensioning diagonally at the same time, mainly controls the tensile stress, supplemented by controlling the elongation value of the steel bars, and checks each other, thereby avoiding damage to the socket and the tensioning box, thereby ensuring the tensioning quality and solving the problem of incomplete grouting in the existing prefabricated rainwater box culvert prestressed tensioning method.

[0031] It should be noted that, in the description of the present invention, terms such as "up", "down", "left", "right", "inside" and "outside" indicating directions or positional relationships are based on the directions or positional relationships shown in the drawings. This is merely for the convenience of description and does not indicate or imply that the device or element must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it cannot be understood as a limitation on the present invention.

[0032] In addition, it should be noted that in the description of the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0033] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A prefabricated rainwater box culvert prestressing method, characterized in that: The steps include: Step S1, connecting two adjacent rainwater culvert sections through steel strands; Step S2, cleaning the anchor gasket and installing it symmetrically on the rainwater box culvert segment, and adjusting the anchor gasket so that its ends are flush; Step S3, calibrating the jack, after which the jack is mounted on a bracket for tensioning, using a symmetrical tensioning method, and using a dual control method during the tensioning process, mainly controlling the tensioning stress, and auxiliaryly controlling the steel bar elongation value, and checking each other; Step S4, after the tensioning is completed, grouting is performed through the grouting holes to complete the anchoring of the tensioning box.

2. The prefabricated rainwater box culvert prestressing method according to claim 1 is characterized in that: When calibrating the jack, use the standard dynamometer calibration method.

3. The prefabricated rainwater box culvert prestressing method according to claim 2 is characterized in that: When checking the jack, the standard dynamometer calibration method is adopted, which is specifically: Connect the oil circuit and power supply of the electric oil pump, supply oil to the jack, move the piston upward, and press the standard dynamometer; when the dynamometer reaches the preset tonnage, read the value from the oil pressure gauge of the jack; recalibrate the pressure readings of each tonnage three times, and then calculate the average value of the corresponding readings of the oil pressure gauge at each tonnage as the pressure gauge reading, and then calculate the oil pressure gauge reading corresponding to the preset tensioning force based on univariate linear regression.

4. The prefabricated rainwater box culvert prestressing method according to claim 3 is characterized in that: After the jack is installed in place, install the tool anchor and reserve space to remove the anchor gasket. Stick plastic tape on the smooth surface of the tool anchor gasket. After the tool gasket is installed, use an iron pipe to knock it firmly.

5. The prefabricated rainwater box culvert prestressing method according to any one of claims 1 to 4, characterized in that: Two adjacent rainwater box culvert sections are connected by unbonded prestressed stranded wires.

6. The prefabricated rainwater box culvert prestressing method according to any one of claims 1 to 4, characterized in that: After the tensioning is completed, a fine stone concrete grouting machine is used to inject grout through the grouting holes.

7. The prefabricated rainwater box culvert prestressing method according to any one of claims 1 to 4, characterized in that: During the prefabrication of the rainwater culvert, a steel pipe with a plastic rubber tube is used as a tensioning hole template. When the template is removed, the steel pipe is taken out to form a complete hole with a plastic rubber tube.

8. The prefabricated rainwater box culvert prestressing method according to any one of claims 1 to 4, characterized in that: Before the steel strand is inserted into the prestressed pipe, remove the plastic rubber tube.

9. The prefabricated rainwater box culvert prestressing method according to any one of claims 1 to 4, characterized in that: During tensioning, first pressurize and tension the A and B tensioning grooves on the same side to 70% at the same time, then pressurize and tension the C and D tensioning grooves on the other side to 70% at the same time, then pressurize and tension the A and B tensioning grooves to 100% at the same time, and finally pressurize and tension the C and D tensioning grooves to 100% at the same time.

10. The prefabricated rainwater box culvert prestressing method according to any one of claims 1 to 4, characterized in that: During tensioning, the relative error between the measured elongation value and the theoretical elongation value is controlled within ±6%, and after tensioning reaches the controlled stress, anchoring is performed after holding the load for 5 minutes.

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