Support system of broken line pre-tensioning beam and construction method

Abstract

The invention discloses a support system of a broken line pre-tensioning beam and a construction method. The support system comprises a tensioning bottom plate, and a plurality of steering supporting devices are arranged on the tensioning bottom plate in the length direction of a prestressed steel beam; a tensioning counter-force beam is arranged at the lower part of the tensioning bottom plate; and the tension counter-force beam is a T-shaped counter-force beam. The T-shaped counter-force beam can be arranged on the tensioning bottom plate in an over-welding mode according to needs, and lateral stable supports are arranged on the two sides of the T-shaped counter-force beam. At least one steel bundle steering device is arranged on each steering supporting device; the steering gear is connected to the steering supporting device through a bolt, and prestress loss is eliminated by adjusting the bolt to steer after tensioning is completed. The T-shaped counter-force beam can be suitable for bending of a steel beam at any position, bending moment formed by stress is better fitted through arrangement of the T-shaped counter-force beam, building materials are saved, carbon emission is reduced, and meanwhile the T-shaped counter-force beam can be used for construction of different concrete beams in cooperation with movement of a steel beam steering gear. The steering gear is improved, so that the prestress loss can be reduced.

Description

Technical Field

[0001] The invention relates to the technical field of prestressed concrete, and in particular to a support system and a construction method for a broken-line pre-tensioned beam. Background Art

[0002] The folded line pre-tensioned beam is a prestressed concrete structure constructed by the pre-tensioning method. It installs a steering device on the tensioning pedestal so that the prestressed steel strands can be turned, positioned, and bent during the tensioning process, thereby forming a prestressed tendon arrangement that is compatible with its stress form. The folded line pre-tensioned beam overcomes the shortcomings of traditional pre-tensioned beams that cannot be used for larger spans, and solves technical problems such as the loose grouting of the post-tensioned prestressed concrete duct and the excessive local pressure at the tensioning end causing the concrete and anchor damage. With the rapid development of prefabricated beams in recent years, the folded line pre-tensioned beam has become the focus of current bridge design research.

[0003] In the prior art, a gravity base is generally provided under the deflector of the bent prestressed steel bar bundle for reaction support, such as the description of the background technology in the first chapter of the master's thesis of Nanchang University "Research on Key Technical Issues of Precast Beams by Broken Line Prestressing Method", and a kind of prestressed concrete inclined web box beam manufacturing equipment disclosed in CN 217434637 U. However, there are obvious shortcomings in the implementation of the project. Usually, the base reaction device of the broken line prestressed beam is in a fixed position and is borne by the concrete gravity pier or even the pile foundation. When different beams need to be prefabricated and their prestressed steel bundles are bent at different positions, it is necessary to find another site to rearrange the base foundation to correspond to the deflectors in different positions.

[0004] In addition, the steering gear has always had the problem of prestress loss, and related studies have believed that it cannot be ignored; for example, the Journal of Wuhan University of Technology published in June 2003, "Experimental Study on Mechanical Properties of Pre-tensioned Beam Pulley Steering Gear", conducted a special study on this. The traditional method of reducing the prestress loss of the steering gear is mainly to use sliding or bearing methods, but it still cannot eliminate the loss. Summary of the invention

[0005] In order to solve the above-mentioned shortcomings of the prior art, the present invention discloses a support system and a construction method for a broken-line pre-tensioned beam.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0007] In the first aspect, the present invention proposes a support system for a broken-line pre-tensioned beam, comprising a T-shaped reaction beam and a tensioning base plate, wherein the tensioning base plate is fixed to the top of the T-shaped reaction beam and is cast as one with the T-shaped reaction beam, and tensioned steel bars are arranged on the top of the T-shaped reaction beam; the tensioning pedestals at the same end are connected by a tensioning crossbeam; and a pair of first steel beam steering devices and a plurality of second steel beam steering devices are arranged between the tensioning pedestals at both ends; the first steel beam steering device is arranged at a position close to the tensioning pedestal, the first steel beam steering device is a multi-layer steering device, and the second steel beam steering device is a single-layer steering device.

[0008] The present invention fundamentally changes the traditional process of setting a counterweight at the bottom of the industry by relying on the structural strength and stress characteristics of the T-type reaction beam. At the same time, unlike the stress characteristics of ordinary T-type beams, the tension position of the T-type beam of the present invention is at the top, and the tensioning bottom plate (steel plate) is also involved in the stress of the T-type beam during tensioning, which can effectively reduce the setting of the steel bars at the top of the T-beam, reduce carbon emissions, and save investment.

[0009] As a further technical solution, stable support columns are arranged at a certain distance at both ends of the flange of the T-shaped reaction beam to ensure the stability of the entire system.

[0010] As a further technical solution, the top of the tensioning base plate can be welded or bolted to a second steel bundle steering device at any position as needed.

[0011] As a further technical solution, the tensioning bottom plate and the T-type tensioning reaction beam are cast simultaneously to form a whole; air holes are arranged on the tensioning bottom plate to make it easier to discharge the gas during the pouring of concrete.

[0012] As a further technical solution, the length of the tensioning reaction beam is longer than that of the prestressed beam.

[0013] As a further technical solution, the first steering support device includes a pair of steering support devices, between which a plurality of layers of bolts are arranged, the plurality of layers of bolts are arranged in parallel up and down, each layer of bolts is installed on the steering support device through nuts, and a plurality of steel bundle deflectors are fixed on each bolt; when prestressing, a bending moment is applied to the bolts at the same time, so that the deflector rotates synchronously with the deformation of the steel bar, avoiding sliding deformation between the deflector and the steel bar, thereby reducing prestress loss.

[0014] As a further technical solution, the second steering support device includes a pair of steering support devices, a bolt is arranged between the pair of steering support devices, the bolt is installed on the steering support device through a nut, and a plurality of steel bundle deflectors are fixed on each bolt; when prestressing, a bending moment is simultaneously applied to the bolt, so that the deflector rotates synchronously with the deformation of the steel bar, avoiding sliding deformation between the deflector and the steel bar, thereby reducing prestress loss.

[0015] As a further technical solution, the prestressed steel strand is fixed to the tension beam by an anchor after being energized by a jack.

[0016] In a second aspect, the present invention further provides a method for tensioning a distributed folding line pre-tensioned beam, which is as follows:

[0017] Step 1. Tie or weld the tensioning bottom plate, anchors and the stress-bearing steel bars of the T-type reaction beam;

[0018] Step 2. Pour concrete into the T-type reaction beam;

[0019] Step 3. Weld or bolt the steering support device on the tensioning base plate, install bolts on the steering support device, and fix both ends of the bolts with nuts, and fix the steel beam steering device on the corresponding bolts; install tensioning pedestals at both ends of the tensioning base plate, and the tensioning pedestals at the same end are connected by tensioning crossbeams;

[0020] Step 4. Use a jack to tension the two ends of the prestressed steel bundle to apply prestress, and at the same time, rotate the bolts on the steering support device accordingly, so that the steering gear rotates accordingly. The rotation direction is the same as the force direction of the prestressed steel bundle, thereby reducing the prestress loss;

[0021] Step 5. After the tensioning is completed, pour the concrete of the prestressed beam of the fold line. At the same time, fix the stress steel strands on the tensioning beams through anchors, and release the prestressed steel strands after the curing is completed.

[0022] Afterwards, when you need to make a broken line to pre-tension the beam again, just repeat steps 3 to 5.

[0023] The beneficial effects of the present invention are as follows:

[0024] The present invention sets a number of steering support devices along the length direction of the prestressed steel bundle on the tensioning base plate, so that the steel bundle steering device can be set to any position; at the same time, in conjunction with the T-type reaction beam at the bottom of the tensioning base plate, it can realize the production of a variety of different prefabricated beams, which are suitable for any beam length within the length range of the reaction beam and the support; the setting of the T-type reaction beam better fits the bending moment formed by the reaction device, effectively saves steel bars and concrete materials, and reduces carbon emissions. At the same time, a new idea is adopted to make the steering device rotate with the tensioning of the prestressed steel bundle, reducing the loss of prestress. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The accompanying drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0026] Figure 1 It is a front view of the present invention;

[0027] Figure 2 is a cross-sectional view of the present invention;

[0028] In the figure: the distances or sizes between parts are exaggerated to show the positions of various parts, and the schematic diagram is for illustration only.

[0029] 11. Prefabricated prestressed beam, 21. Prestressed steel beam, 22. Prestressed steel beam, 31. Steel beam steering device, 32. Steel beam steering device, 33. Bolt, 34. Nut, 35. Steering support device, 36 Steel beam steering device, 41. Steel beam steering device,

[0030] 51. T-type reaction beam, 52. tensioning base plate, 53. anchor, 54. support column, 61. tensioning pedestal, 71. tensioning beam, 81. jack, 82. jack, 91. anchor, 92. anchor. DETAILED DESCRIPTION

[0031] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used in the present invention have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0032] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present invention. As used herein, unless otherwise explicitly stated in the present invention, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "include" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof;

[0033] For the convenience of description, if the words "up", "down", "left" and "right" appear in the present invention, they only indicate that they are consistent with the up, down, left and right directions of the drawings themselves, and do not limit the structure. They are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the referred 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.

[0034] As introduced in the background technology, there are deficiencies in the prior art. In order to solve the above technical problems, the present invention proposes a tensioning construction system and method for a distributed broken-line pre-tensioned beam.

[0035] In a typical embodiment of the present invention, Figure 1 , Figure 2As shown, the present embodiment discloses a support system and construction method for a broken line pre-tensioned beam, including a T-shaped reaction beam 51. The T-shaped reaction beam 51 is different from a general T-shaped beam in that the main tensile steel bars are arranged at the bottom. The tensile steel bars of the present invention are mainly arranged at the top. The tensile steel bars are arranged along the length direction of the T-shaped reaction beam 51. The end of the compression zone at the bottom of the T-beam can be expanded as needed, which is specifically determined by the cost-effectiveness requirements; the tensile steel bars are not shown in the figure; a tensioning bottom plate 52 is fixed on the top of the T-shaped reaction beam 51, and a support is also arranged at the bottom edge of the T-shaped reaction beam 51. Column 54; the tensioning bottom plate 52 is a steel plate, and the tensioning bottom plate 52 is anchored in the T-type reaction beam by a plurality of anchors 53. During casting, the tensioning bottom plate 52 is cast together with the T-type reaction beam; the present invention fundamentally changes the traditional process of setting a counterweight at the bottom in the industry by relying on the structural strength and force characteristics of the T-type reaction beam; the tensioning bottom plate 52 also participates in the force of the T-type reaction beam 51 during tensioning, which can effectively reduce the setting of the steel bars at the top of the T-type reaction beam 51; the bottom compression zone of the T-type reaction beam 51 can be expanded at the end as needed, which is specifically determined by the cost-effectiveness requirements.

[0036] A plurality of steel strand steering devices are installed on the tensioning bottom plate 52 along the length direction of the prestressed steel strands, specifically referring to the steel strand steering device 31, the steel strand steering device 32 and the steel strand steering device 41 in the attached figure; the steel strand steering device 31 and the steel strand steering device 32 correspond to the second steel strand steering device described above, and are single-layer steel strand steering devices; the steel strand steering device 41 corresponds to the first steel strand steering device described above, and is a double-layer steel strand steering device;

[0037] Each of the steel beam steering devices 31 and 32 has the same structure, and each includes a pair of supporting devices 35. A bolt 33 is provided between each pair of steering supporting devices. The bolt 33 is installed on the steering supporting device 35 through a nut, and a plurality of steel beam steering devices 31 are fixed on the bolt 33, that is, the steel beam steering device 31 is fixed on the bolt 33, and the two do not rotate relative to each other, that is, there is no friction resistance between the steel beam steering device 31 and the bolt 33. In the process of applying prestress, a certain torque is applied to the bolt to make the bolt rotate together with the steel beam steering device 31, thereby reducing the loss of prestress;

[0038] Furthermore, the steel beam steering device 41 also includes a pair of support devices 35, between which two bolts 33 are arranged, and the two bolts 33 are arranged in parallel up and down, and each bolt 33 is installed on the steering support device 35 through a nut, and a plurality of steel beam steering devices 31 are fixed on each bolt 33, that is, the steel beam steering device 31 is fixed on the bolt 33, and the two do not rotate relative to each other, that is, there is no friction resistance between the steel beam steering device 31 and the bolt 33. In the process of applying prestress, a certain torque is applied to the bolt at the same time, so that the bolt and the steel beam steering device 31 rotate together, thereby reducing the prestress loss. It should be noted that: the bolts 33 of the steel beam steering device 41 can be set in multiple, not limited to two, and the multiple bolts 33 are parallel to each other in the height direction. This embodiment only takes two as an example for explanation; the specific number of layers is related to the number of layers of the prestressed steel beam 22.

[0039] Furthermore, it should be noted that the steering support device 35 and the tensioning base plate 52 can be welded together or connected together by bolts; and in order to increase the adaptability of the overall support, when different beams are prefabricated, the position of the steering support device 35 on the tensioning base plate 52 can be adjusted as needed. When the steering support device 35 and the tensioning base plate 52 are welded, the steering support device 35 can be cut off from the tensioning base plate 52 and then welded to other positions; when the steering support device 35 and the tensioning base plate 52 are bolted, a number of connecting holes can be set on the tensioning base plate 52 in advance, and then the different connecting holes of the steering support device 35 can be connected, and then the position can be adjusted; so that the steel beam deflector can be set to any position, so as to realize the bending of the prestressed steel beam at any position.

[0040] Furthermore, a plurality of steering support devices 35 are installed on the tensioning base plate 52 along the length direction of the prestressed steel bundle, which is equivalent to setting up multiple sets of steel bundle steering devices 31, thereby realizing distributed tensioning. The distributed tensioning in this embodiment can significantly reduce the vertical component of each fold line compared with a single tensioning, disperse the force on the T-type reaction beam 51 and the tensioning base plate 52, reduce the shear force, bending moment and corresponding deformation of related components, significantly increase the safety factor of the base plate and the steering device, and reduce the engineering risk.

[0041] As a further technical solution, when the broken line beam is tensioned, it is mainly necessary to provide reaction force in the steel beam deflector 31, steel beam deflector 31, and steel beam deflector 41. The positions of the steel beam deflectors 31, steel beam deflectors 31, and steel beam deflectors 41 of different beams are different. The present invention can set a reaction beam with a longer distance, and can apply reaction force to prestressed beams of different lengths and positions. At the same time, the T-type reaction beam is used, which is arranged according to its force characteristics. Since the vertical component forces of the steel beam deflector and the steering support device are a pair of reaction forces, it does not require too much load in the vertical direction to balance. The key lies in the stiffness and shear resistance of the bottom. The use of a T-type reaction beam can well match the force conditions and provide the required support. Specifically, the length of the tensioning reaction beam is longer than that of the prestressed beam. Figure 1 shown.

[0042] As a further technical solution, tensioning pedestals 61 are provided at both ends of the tensioning base plate 42, and the tensioning pedestals 61 located at the same end are connected by a tensioning crossbeam 71; after a certain tensioning force is applied to the prestressed steel bundle 22 by a jack 81, the prestressed steel bundle 22 is fixed to the tensioning crossbeam 71 by an anchor 82.

[0043] The specific construction methods are as follows:

[0044] Step 1. Select a suitable site to cast the T-type reaction beam. The pre-tensioning of the broken line beam is generally suitable for the prefabrication of beams with a length of less than 60m, so the length of the T-type reaction beam can be determined as 70m. According to the force of the T-type reaction beam, after the steel cage is made, the tensioning base plate, anchors and steel cage are tied or welded together;

[0045] Step 2. Pour concrete into the T-type reaction beam;

[0046] Step 3. Install multiple groups of steering support devices 35 on the tensioning base plate 42, install bolts on the steering support devices, and fix the two ends of the bolts by nuts, and fix the steel beam diverters on the corresponding bolts; install tensioning pedestals 61 at both ends of the tensioning base plate, and the tensioning pedestals 61 at the same end are connected by tensioning crossbeams 71;

[0047] Step 5. Use jacks 81 and 82 to tension the two ends of the prestressed steel bundle 22, and then fix the prestressed steel bundle 22 on the tensioning beam through anchors; during the tensioning process, the bolts on the steering support device are rotated accordingly, so that the steering gear rotates accordingly, and the rotation direction is the same as the force direction of the prestressed steel bundle, thereby reducing the prestress loss;

[0048] Step 6. After the tensioning is completed, pour the concrete of the prestressed beam of the fold line, and fix the prestressed steel strands on the tensioning beams through anchors. After the curing is completed, release the prestressed steel strands.

[0049] Afterwards, when you need to make a fold line to pre-tension the beam again, just repeat steps 3 to 6.

[0050] In the present invention, the counterweight is replaced by the T-type reaction beam 52, which saves the process of making the counterweight separately; relying on the structural strength and force characteristics of the T-type reaction beam, the traditional process of setting the counterweight at the bottom in the industry is fundamentally changed. The support system of the broken line pre-tensioned beam is different from the general T-type beam that sets the main tensile steel bars at the bottom. The tensile steel bars of the present invention are mainly set at the top, and the compression area at the bottom of the T beam can be expanded at the end as needed, which is specifically determined by the cost-effectiveness.

[0051] The present invention sets a number of steering support devices along the length direction of the prestressed steel bundle on the tensioning base plate, so that the steel bundle steering device can be set to any position; at the same time, in conjunction with the T-type reaction beam at the bottom of the tensioning base plate, it can realize the production of a variety of different prefabricated beams, which are suitable for any beam length within the length range of the reaction beam and the support; the setting of the T-type reaction beam better fits the bending moment formed by the reaction device, effectively saves steel bars and concrete materials, and reduces carbon emissions. At the same time, a new idea is adopted to make the steering device rotate with the tensioning of the prestressed steel bundle, reducing the loss of prestress.

[0052] Finally, it should be noted that relational terms such as first and second are merely used to distinguish one entity or operation from another entity or operation, but do not necessarily require or imply any actual relationship or order between these entities or operations.

[0053] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A support system for a fold line pre-tensioned beam, characterized in that: It includes a T-shaped reaction beam and a tensioning base plate, wherein the tensioning base plate is fixed on the top of the T-shaped reaction beam and cast as one body with the T-shaped reaction beam; the tensioning pedestals at the same end are connected by a tensioning crossbeam; and a pair of first steel beam steering devices and a plurality of second steel beam steering devices are arranged between the tensioning pedestals at both ends; the first steel beam steering device is arranged at a position close to the tensioning pedestal, the first steel beam steering device is a multi-layer steering device, and the second steel beam steering device is a single-layer steering device.

2. The support system of the fold line pre-tensioned beam according to claim 1, characterized in that: The first steering support device comprises a pair of steering support devices, between which a plurality of layers of bolts are arranged in parallel, each bolt is installed on the steering support device through a nut, and a plurality of steel beam steering devices are fixed on each bolt.

3. The support system of the fold line pre-tensioned beam according to claim 1, characterized in that: The second steering support device comprises a pair of steering support devices, a bolt is arranged between the pair of steering support devices, the bolt is installed on the steering support device through a nut, and a plurality of steel beam steering gears are fixed on each bolt.

4. The support system of the fold line pre-tensioned beam according to claim 1, characterized in that: The tensioning base plate and the T-shaped reaction beam are connected and reinforced by connecting pieces.

5. The support system of the fold line pre-tensioned beam according to claim 1, characterized in that: The top of the tensioning base plate can be welded or bolted to the second steel strand steering device at any position as needed.

6. The support system of the fold line pre-tensioned beam according to claim 1, characterized in that: Air holes are set on the tensioning base plate to make it easier for gas to be discharged during concrete pouring.

7. The support system of the fold line pre-tensioned beam according to claim 1, characterized in that: The length of the tension reaction beam is longer than that of the prestressed beam.

8. The support system of the fold line pre-tensioned beam according to claim 1, characterized in that: Stable support columns are arranged at a certain distance at both ends of the flange of the T-type reaction beam to ensure the stability of the entire system.

9. The support system of the fold line pre-tensioned beam according to claim 1, characterized in that: After the prestressed steel strand is energized by a jack, it is fixed to the tension beam by an anchor.

10. The construction method of the support system of the fold line pre-tensioned beam according to any one of claims 1 to 9, characterized in that: Step 1. Tie or weld the tensioning bottom plate, anchors and the stress-bearing steel bars of the T-type reaction beam; Step 2. Pour concrete into the T-type reaction beam; Step 3. Weld or bolt the steering support device on the tensioning base plate, install bolts on the steering support device, and fix both ends of the bolts with nuts, and fix the steel beam steering device on the corresponding bolts; install tensioning pedestals at both ends of the tensioning base plate, and the tensioning pedestals at the same end are connected by tensioning crossbeams; Step 4. Use a jack to tension the two ends of the prestressed steel bundle to apply prestress, and at the same time, rotate the bolts on the steering support device accordingly, so that the steering gear rotates accordingly. The rotation direction is the same as the force direction of the prestressed steel bundle, thereby reducing the prestress loss; Step 5. After the tensioning is completed, pour the concrete of the prestressed beam of the fold line, and fix the prestressed steel strands on the tensioning beams through anchors. After the curing is completed, release the prestressed steel strands.

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