Hollow slab beam prefabrication process

Abstract

The invention relates to a hollow slab beam prefabrication process. The process comprises the following steps that a pedestal is cleaned, steel strands penetrate into the pedestal, the ends of part of the steel strands are sleeved with PVC pipes, the steel strands are tensioned, steel bars are bound to form a steel reinforcement cage, an inner mold penetrates through the steel reinforcement cage, and side formworks and end formworks are installed; the inner mold is inflated, upper and lower layers of positioning steel bars are installed, and the positioning steel bars fix the position of the inner mold; deflating the inner mold, pouring concrete at the bottom plate of the hollow slab beam, and vibrating; the inner mold is inflated, concrete at webs on the two sides of the hollow slab girder is poured, vibration is conducted, and then a top plate is poured; curing the hollow slab girder, after curing is completed, releasing the steel strand, cutting the redundant steel strand, deflating and extracting the inner mold; in the pouring process, the inner mold is deflated firstly, then the concrete at the bottom plate of the hollow slab beam is poured, workers can conveniently check and vibrate the concrete at the bottom plate of the hollow slab beam and accurately control the thickness of the bottom plate, and the situation that the service life of the hollow slab beam is affected due to uneven vibration of the concrete at the bottom plate of the hollow slab beam or insufficient thickness of the bottom plate is avoided.

Description

Technical Field

[0001] The invention belongs to the technical field of hollow slab beam preparation, and relates to a hollow slab beam prefabrication process. Background Art

[0002] In the field of construction and bridge engineering, with the rapid development of infrastructure construction, the requirements for beam structures are becoming increasingly stringent. Traditional solid beams have a large deadweight, are difficult to transport and construct, and consume a lot of materials. Simply supported beam structures are widely used in small and medium span scenarios due to their clear force and simple structure, but their deadweight still needs to be optimized. Hollow slab beams came into being. Their internal hollow design effectively reduces deadweight, can reduce material costs to a certain extent, and facilitate transportation and installation.

[0003] At present, the prefabrication process of hollow slab beams is the pre-tensioning prefabrication process, and the specific processes are: cleaning the pedestal (bottom mold) and installing the mold release agent template. Straighten the steel bars, remove rust, lay the bars into a skeleton, and tension the prestressed tendons. Place the inflatable inner mold and position it. Pour the concrete in layers obliquely and vibrate it to make it dense. After the pouring is completed, it is cured for more than 14 days. After the concrete strength reaches the standard, the prestressed tendons are released, the excess parts are cut, and finally the inflatable inner mold is deflated and pulled out. However, in the actual pouring process, because the inner mold blocks the bottom plate of the hollow slab beam, when pouring the bottom plate concrete, it is difficult for the material to reach the bottom of the inner mold smoothly, and it is difficult to vibrate the bottom plate concrete under the inner mold to make it dense, resulting in the low strength and thin thickness of the bottom plate concrete of the formed hollow slab beam, and it is difficult to completely wrap the steel strands in the concrete, resulting in the decrease of the bearing capacity and durability of the hollow slab beam structure, and reducing the service life of the hollow slab beam. Summary of the invention

[0004] The purpose of the present invention is to provide a hollow slab beam prefabrication process, which first deflates the inflatable inner mold during the pouring process and then pours the bottom plate concrete, so that the concrete material can smoothly reach the bottom of the inner mold, which is convenient for workers to pour and check the vibration of the hollow slab beam bottom plate concrete, and avoid the defects of loose vibration of the hollow slab beam bottom plate concrete and insufficient bottom plate thickness.

[0005] In order to achieve the above technical purpose, the technical solution of the present invention is:

[0006] A hollow slab beam prefabrication process comprises the following steps:

[0007] (1) Clean the pedestal, insert the steel strands, put PVC pipes on the ends of some of the steel strands, tension the steel strands, tie the steel bars to form a steel cage, pass the inflatable inner mold through the steel cage, and install two side templates and two end templates.

[0008] (2) Inflate the inflatable inner mold, install positioning steel bars above and below the inner mold, fix the inner mold with the positioning steel bars to prevent the inner mold from floating up and sinking, ensure that the hollow position of the inner cavity of the slab beam after pouring is consistent with the design drawings, and ensure that the top plate thickness and bottom plate thickness of the hollow slab beam are consistent with the design drawings. When workers actually tie the steel bars, there are situations such as poor straightness of the steel bars and deviation and unevenness of the steel bars caused by the workers' tying operations. In view of this, if the inflatable inner mold is not inflated in advance, it is easy to cause deviation in the position of the inflatable inner mold. Therefore, by pre-inflation, the position of the inflatable inner mold for pouring concrete is simulated, so that it is easier for workers to find the installation position of the positioning steel bars, improving construction accuracy and work efficiency. Therefore, the positioning steel bars have the effect of positioning and restraining the inner mold, which can effectively ensure construction accuracy.

[0009] (3) Deflate the inflatable inner mold and pour concrete at the bottom plate of the hollow slab beam. When the concrete at the bottom plate of the hollow slab beam reaches the positioning steel bars, stop pouring the concrete at the bottom plate of the hollow slab beam and vibrate the bottom plate concrete.

[0010] (4) Inflate the inflatable inner mold, continue pouring and vibrating the concrete at the webs on both sides of the hollow slab beam, and after the web concrete is poured, pour and vibrate the top slab concrete.

[0011] During the construction process, the bottom plate of the hollow slab beam is poured first, and then the inflatable inner mold is placed in, and then the web is poured after inflation. The time interval between pouring the web and the bottom plate is relatively long. At this time, the concrete at the bottom plate is easy to solidify, and there is a construction interface between the concrete of the web, which not only affects the appearance of the hollow slab beam, but also easily causes stratification, resulting in gaps, which easily leads to water seepage. Therefore, the inflatable inner mold is first placed in the steel cage. After the concrete pouring at the bottom plate of the hollow slab beam is completed, the inflatable inner mold is inflated in time, and then the concrete at the web is poured. In this way, the concrete at the web can be blended with the concrete at the bottom plate to avoid stratification and water seepage, and time can also be saved.

[0012] In addition, when pouring concrete, the positioning steel bars are used as reference marks to facilitate observation by construction workers. When pouring to the location of the positioning steel bars, the pouring operation is stopped to ensure the thickness of the bottom plate of the hollow slab beam.

[0013] (5) Curing the hollow slab beam, after the curing is completed, the inflatable inner mold is pulled out, the steel strands are released, the excess steel strands are cut, and the inflatable inner mold is deflated;

[0014] (6) Roughen the side wall of the notch in the bottom plate at the end of the hollow slab beam, install a template at the notch of the hollow slab beam, pour the repair material, and remove the template after the repair material solidifies. Roughening the side wall of the notch of the hollow slab beam can improve the stability of the repair material filling the notch.

[0015] Specifically, a protrusion is provided on the inner side wall of the end template, the protrusion is close to one side of the pedestal, and the protrusion and the end template are provided with through holes for steel strands and PVC pipes to pass through. The protrusion occupies a part of the space of the casting bottom plate, so that a gap is reserved at the end of the bottom plate of the hollow slab beam, which is convenient for subsequent filling of the gap, so that the pipe opening of the PVC pipe, the steel strands in the PVC pipe and the steel strands exposed at the gap can be blocked, preventing rainwater from penetrating into the hollow slab beam from the pipe opening of the PVC pipe and the exposed prestressed tendons, thereby preventing the steel strands from rusting, which is beneficial to improving the durability of the hollow slab beam and avoiding shortening the life of the hollow slab beam.

[0016] Furthermore, in step (1), a protective sleeve is provided on the outer cover of the inflatable inner mold, and the protective sleeve is a nylon cloth sheet, one side of the nylon cloth sheet has a first connecting piece, and the other side of the nylon cloth sheet has a second connecting piece, and the first connecting piece and the second connecting piece are connected to form the nylon cloth sheet into a protective sleeve, and a plurality of binding ropes are provided on the end surface of the protective sleeve, and the binding ropes are connected to the inflation tube of the inflatable inner mold; the inflatable inner mold is wrapped with the nylon cloth sheet, and then tied with the binding ropes to prevent the inflatable inner mold from slipping during movement, and the nylon cloth sheet is wrapped on the outside of the inflatable inner mold to prevent the sharp parts in the steel cage from scratching the inflatable inner mold, causing the inflatable inner mold to be damaged and leaking; when winding, the protective sleeve and the inflatable inner mold can be inserted into the steel cage by manual dragging or by motor winding; after the protective sleeve and the inflatable inner mold are inserted into the steel cage, the tail of the inflatable inner mold is fixed, and the protective sleeve is continued to be moved to move the protective sleeve out of the steel cage.

[0017] Specifically, the first connecting member includes a first magnetic strip disposed on the nylon cloth sheet, the first magnetic strip is provided with a plurality of slots, and the plurality of slots are evenly distributed along the length direction of the nylon cloth sheet; the second connecting member includes a second magnetic strip disposed on the nylon cloth sheet, the second magnetic strip is provided with an insert block inserted into the slot.

[0018] The end of the nylon cloth piece away from the binding rope is hinged with a support plate, the tail end of the first magnetic strip is provided with a limiting hole, the slot at the tail end of the first magnetic strip is connected to the limiting hole, the plug block at the tail end of the second magnetic strip is provided with a plug hole, the end of the support plate away from the hinge point is inserted into the limiting hole and the plug hole, a telescopic block is provided in the plug hole, a number of springs are provided between the telescopic block and the wall of the plug hole, and the support plate, the plug block and the first magnetic strip are provided with a through hole for the telescopic block to pass through.

[0019] During construction, first place the inflatable inner mold on the nylon cloth sheet, flip the two sides of the nylon cloth sheet, insert the plug block into the slot, and the first magnetic strip absorbs the second magnetic strip, so as to prevent the nylon cloth sheet from loosening due to friction or pulling with the steel cage during movement, thereby effectively protecting the inflatable inner mold; then flip the support piece at the tail end of the nylon cloth sheet, insert its head into the limiting hole and the plug hole, and extend the telescopic block out of the through hole, so as to limit the tail end of the inflatable inner mold, and prevent the inflatable inner mold from falling from the protective sleeve when the protective sleeve is moved. After the inflatable inner mold and the protective sleeve are inserted into the steel cage, press the telescopic block to move the support piece out of the limiting hole and the plug hole, exposing the tail of the inflatable inner mold, which is convenient for fixing the tail of the inflatable inner mold, so that the protective sleeve can be dragged to move the protective sleeve out of the steel cage.

[0020] The present invention first deflates the inflatable inner mold and then pours the concrete at the bottom plate of the hollow slab beam, so it is convenient for workers to pour and check the vibration of the bottom plate of the hollow slab beam, and then inflate the inflatable inner mold and pour the web and top plate of the hollow slab beam. By adjusting the order of inflating and deflating the inflatable inner mold and pouring concrete, it is possible to avoid uneven vibration of the bottom plate concrete of the hollow slab beam or insufficient bottom plate thickness, which may affect the life of the hollow slab beam. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a structural schematic diagram of a protective sleeve and an inflatable inner mold penetrating a steel cage in a hollow slab beam prefabrication process in an embodiment of the present invention.

[0022] Figure 2 It is a schematic diagram of the structure of the side template and the end template in an embodiment of the present invention.

[0023] Figure 3 It is a schematic diagram of the structure of positioning steel bars in an embodiment of the present invention.

[0024] Figure 4 It is a cross-sectional view of a slot and an insert block according to an embodiment of the present invention.

[0025] Figure 5 It is a cross-sectional view showing another perspective of the slot and the plug-in block in the embodiment of the present invention.

[0026] Figure 6 It is a manifestation Figure 5 Enlarged view of part A in the middle.

[0027] Explanation of the accompanying reference numerals: 1. pedestal; 2. steel cage; 3. PVC pipe; 4. inflatable inner mold; 5. side mold; 6. end mold; 7. protrusion; 8. through hole; 9. protective cover; 10. binding rope; 11. first magnetic strip; 12. slot; 13. second magnetic strip; 14. plug-in block; 15. support plate; 16. limiting hole; 17. plug-in hole; 18. telescopic block; 19. spring; 20. through hole; 21. steel strand; 22. positioning steel bar. DETAILED DESCRIPTION

[0028] The following is combined with Figure 1-6 The present invention is described in further detail.

[0029] refer to Figure 1-3 , a hollow slab beam prefabrication process, comprising the following steps:

[0030] (1) Clean the pedestal 1, insert the steel strands 21, put the PVC tube 3 on the ends of some of the steel strands 21, tension the steel strands 21, tie the steel bars to form a steel cage 2, and pass the inflatable inner mold 4 through the steel cage 2. In this embodiment, the inflatable inner mold 4 is not limited to airbags, PVC, polyurethane foam, steel structure and other inner molds.

[0031] When inserting the inflatable inner mold 4, first wrap the protective sleeve 9 on the outside of the inflatable inner mold 4, and a plurality of binding ropes 10 are provided on the end surface of the protective sleeve 9, and the binding ropes 10 are connected to the inflatable tube 3 of the inflatable inner mold 4; the inflatable inner mold 4 and the protective sleeve 9 are passed through the steel cage 2. In this embodiment, since the workers manually bind the steel cage 2, it is easy to cause the steel bars in the steel cage 2 to be different in height. Therefore, in actual construction, the rope is connected to the binding rope, and the worker manually pulls the rope to drag the inflatable inner mold 4 and the protective sleeve 9, and adjusts the position of the inflatable inner mold 4 and the protective sleeve 9 in time until the two are inserted into the steel cage 2, and then unties the binding rope 10, fixes the tail of the inflatable inner mold 4, and continues to drag the protective sleeve 9 to move the protective sleeve 9 out of the steel cage 2. In other embodiments, the motor can also be used to drive the reel to rotate and wind the rope, instead of the worker manually dragging the rope, which is conducive to reducing the workload of the workers.

[0032] (2) Install two side templates 5 and two end templates 6. Specifically, a protrusion 7 is provided on the inner wall of the end template 6. The protrusion 7 is close to one side of the pedestal 1. The protrusion 7 and the end template 6 are provided with a through hole 8 for the steel strand 21 and the PVC tube 3 to pass through;

[0033] (3) Inflate the inflatable inner mold 4, install the upper and lower layers of positioning steel bars 22, and fix the position of the inflatable inner mold 4 by the positioning steel bars 22;

[0034] (4) Deflate the inflatable inner mold 4 and pour concrete at the bottom plate of the hollow slab beam. When the concrete at the bottom plate of the hollow slab beam is injected to the positioning steel bars 22, stop pouring the concrete at the bottom plate of the hollow slab beam and vibrate the concrete;

[0035] (5) Inflate the inflatable inner mold 4, pour concrete on the webs on both sides of the hollow slab beam, vibrate it, and then pour the top plate;

[0036] (6) Curing the hollow slab beam, after the curing is completed, the steel strands 21 are released, the excess steel strands 21 are cut, and the air is released and the inflatable inner mold 4 is pulled out;

[0037] (7) Roughen the side wall of the notch at the end of the bottom plate of the hollow slab beam, install the formwork at the notch of the hollow slab beam, pour the repair material, and remove the formwork after the repair material solidifies.

[0038] refer to Figure 4-6 Specifically, the protective cover 9 is a nylon cloth piece, one side of the nylon cloth piece has a first connecting piece, and the other side of the nylon cloth piece has a second connecting piece. After the first connecting piece and the second connecting piece are connected, the nylon cloth piece forms the protective cover 9.

[0039] The first connecting member includes a first magnetic strip 11 arranged on the nylon cloth sheet, and the first magnetic strip 11 is provided with a plurality of slots 12, and the plurality of slots 12 are evenly distributed along the length direction of the nylon cloth sheet. The second connecting member includes a second magnetic strip 13 arranged on the nylon cloth sheet, and the second magnetic strip 13 is provided with an insert 14 inserted into the slot 12.

[0040] A support plate 15 is hinged on one end of the nylon cloth piece away from the binding rope 10. In the present embodiment, the support plate 15 is in an arc shape so that it can better fit the tail end of the first magnetic strip 11. A limiting hole 16 is provided, and the slot 12 at the tail end of the first magnetic strip 11 is connected to the limiting hole 16. The plug block 14 at the tail end of the second magnetic strip 13 is provided with a plug hole 17. The end of the support plate 15 away from the hinge point is inserted into the limiting hole 16 and the plug hole 17. A telescopic block 18 is provided in the plug hole 17. A plurality of springs 19 are provided between the telescopic block 18 and the hole wall of the plug hole 17. A through hole 20 for the telescopic block 18 to pass through is provided on the support plate 15, the plug block 14 and the first magnetic strip 11.

[0041] The above are all preferred embodiments of the present invention, and are not intended to limit the protection scope of the present invention. Therefore, any equivalent changes made based on the structure, shape, and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A hollow slab beam prefabrication process, characterized in that: The steps include: (1) Clean the pedestal (1), insert the steel strands (21), put the PVC tube (3) on the ends of some of the steel strands (21), tension the steel strands (21), tie the steel bars to form a steel cage (2), pass the inflatable inner mold (4) through the steel cage (2), and install two side molds (5) and two end molds (6); (2) Inflate the inflatable inner mold (4), install upper and lower layers of positioning steel bars (22), and the positioning steel bars (22) fix the position of the inflatable inner mold (4); (3) Deflate the inflatable inner mold (4), pour concrete at the bottom plate of the hollow slab beam, and vibrate it; (4) Inflate the inflatable inner mold (4), pour concrete on the webs on both sides of the hollow slab beam, vibrate it, and then pour the top slab; (5) Curing the hollow slab beam, after the curing is completed, the steel strands (21) are released, the excess steel strands (21) are cut, and the air is released and the inflatable inner mold (4) is pulled out.

2. A hollow slab beam prefabrication process according to claim 1, characterized in that: In step (3), when the concrete at the bottom plate of the hollow slab beam is poured to the lower layer of positioning steel bars (22), the pouring of concrete at the bottom plate of the hollow slab beam is stopped.

3. The hollow slab beam prefabrication process according to claim 1, characterized in that: A convex block (7) is provided on the inner side wall of the end template (6), the convex block (7) is close to one side of the pedestal (1), and a through hole (8) for the steel strand (21) and the PVC pipe (3) to pass through is provided on the convex block (7) and the end template (6).

4. The hollow slab beam prefabrication process according to claim 1, characterized in that: The method also includes step (6), installing a template at the notch of the hollow slab beam, pouring a repair material, and removing the template after the repair material solidifies.

5. The hollow slab beam prefabrication process according to claim 4, characterized in that: In step (6), before installing the formwork, the side walls of the hollow slab beam notch are roughened.

6. The hollow slab beam prefabrication process according to claim 1, characterized in that: In step (1), the inflatable inner mold (4) is provided with a protective sleeve (9) on its outer shell, and a plurality of binding ropes (10) are provided on the end surface of the protective sleeve (9), and the binding ropes (10) are connected to the inflation tube (3) of the inflatable inner mold (4); after the protective sleeve (9) and the inflatable inner mold (4) are inserted into the steel cage (2), the tail of the inflatable inner mold (4) is fixed, and the protective sleeve (9) is continued to be moved to remove the protective sleeve (9) from the steel cage (2).

7. A hollow slab beam prefabrication process according to claim 6, characterized in that: The protective cover (9) is a nylon cloth sheet, one side of the nylon cloth sheet has a first connecting piece, and the other side of the nylon cloth sheet has a second connecting piece, and the nylon cloth sheet forms the protective cover (9) after the first connecting piece and the second connecting piece are connected.

8. The hollow slab beam prefabrication process according to claim 7, characterized in that: The first connecting member comprises a first magnetic strip (11) arranged on the nylon cloth sheet, the first magnetic strip (11) being provided with a plurality of slots (12), the plurality of slots (12) being evenly distributed along the length direction of the nylon cloth sheet, and the second connecting member comprises a second magnetic strip (13) arranged on the nylon cloth sheet, the second magnetic strip (13) being provided with an insert block (14) inserted into the slot (12).

9. A hollow slab beam prefabrication process according to claim 8, characterized in that: The end of the nylon cloth sheet away from the binding rope (10) is hinged with a support plate (15), the tail end of the first magnetic strip (11) is provided with a limiting hole (16), the slot (12) at the tail end of the first magnetic strip (11) is connected to the limiting hole (16), the plug block (14) at the tail end of the second magnetic strip (13) is provided with a plug hole (17), the end of the support plate (15) away from the hinge point is inserted into the limiting hole (16) and the plug hole (17), a telescopic block (18) is provided in the plug hole (17), a plurality of springs (19) are provided between the telescopic block (18) and the hole wall of the plug hole (17), and a through hole (20) for the telescopic block (18) to pass through is provided on the support plate (15), the plug block (14) and the first magnetic strip (11).

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