The bottom formwork of a closed structure roof slab and its construction method

Abstract

The present invention discloses a bottom formwork for the top plate of a closed structure and its construction method, which relates to the field of bridge construction. The steps of the method include: fixing a floating box-type bottom formwork inside the anchor block, with the top height of the floating box-type bottom formwork being the same as the height of the outer wall of the anchor block; injecting water into the anchor block until the height of the water is basically the same as the height of the outer wall; after performing concrete pouring work on the top of the floating box-type bottom formwork, pumping out the water inside the anchor block. The present invention enables the floating box-type bottom formwork structure to obtain buoyancy by injecting water into the closed structure, reducing the overall load borne by the structure during the construction of the top plate of the closed structure. The present invention effectively solves the problems of large material consumption and high construction difficulty during the construction of the top plate of the closed structure.

Description

Technical Field

[0001] The present invention relates to the field of bridge construction, and in particular to a bottom formwork of a closed structure top plate and a construction method thereof. Background Art

[0002] Anchors are the main load-bearing components of suspension bridges. They mainly resist the tension from the main cables and transmit it to the foundation. According to the different force forms, they can be divided into gravity anchors, tunnel anchors and rock anchors.

[0003] With the rapid development of bridge technology in my country, the span of suspension bridges has gradually increased, and the corresponding anchor foundation size has also gradually increased. The construction of large anchor foundations requires a large amount of concrete, so some suspension bridge anchors are designed as closed structures with a hollow middle.

[0004] Currently, there are two existing construction methods for the top plate construction of such large enclosed anchor foundations:

[0005] 1. Steel pipe column support method: This method is to set up a steel pipe column support inside the anchor as the bottom formwork for the top plate casting. Since the anchor top plate is a sealed structure after casting, it is difficult to remove the support inside the anchor, which requires a large amount of steel material to be invested at one time. The construction cost of this method is relatively high.

[0006] 2. Precast beam + precast slab method: This method sets precast concrete beams as distribution beams on the anchor exterior wall, and covers the top of the precast beams with precast slabs as the top plate bottom formwork. Because the anchor size is generally large, the precast beams and precast slabs need to be hoisted one by one to the top of the anchor exterior wall for installation, so the construction period of this method is longer. Summary of the Invention

[0007] In view of the defects in the prior art, the present invention solves the technical problem of how to shorten the construction period of anchoring and capping construction and save the material cost of construction.

[0008] To achieve the above objectives, the present invention provides a method for constructing a bottom formwork of a closed structure top plate, the method comprising the following steps:

[0009] Fix the pontoon bottom formwork inside the anchor, with the top height of the pontoon bottom formwork being substantially the same as the height of the outer wall of the anchor; inject water into the anchor until the water height is substantially the same as the height of the outer wall; after pouring concrete on the top of the pontoon bottom formwork, pump out the water inside the anchor.

[0010] On the basis of the above technical solution, before fixing the pontoon-type bottom formwork inside the anchor, the following steps are specifically included: making the pontoon-type bottom formwork.

[0011] On the basis of the above technical solution, before fixing the floating box bottom die inside the anchor block, the following steps are specifically included: installing a mechanism for fixing the floating box bottom die on the inner wall of the outer wall.

[0012] On the basis of the above technical solution, during the process of pouring concrete on the top of the floating box bottom die, the following steps are specifically included: pouring concrete in layers according to the bearing capacity of the floating box bottom die, and after the previous layer of concrete has solidified, then proceeding with the subsequent concrete pouring.

[0013] On the basis of the above technical solution, the surface of the floating box bottom plate is parallel to the surface of the floating box top plate. The floating box top plate is arranged on the top of the floating box bottom plate, and the floating box bottom plate and the floating box top plate are fixed by the floating box side plates.

[0014] On the basis of the above technical solution, several floating box bottom plate ribs are arranged on the top surface of the floating box bottom plate, several floating box top plate ribs are arranged on the bottom surface of the floating box top plate, and several floating box side plate ribs are arranged on the inner side of the floating box side plates.

[0015] On the basis of the above technical solution, several floating box partitions are arranged between the floating box bottom plate and the floating box top plate. Floating box partition ribs are arranged on both sides of the floating box partitions, and several trusses are arranged between adjacent floating box partitions.

[0016] On the basis of the above technical solution, the floating box side plates are fixed to the inner wall of the outer wall by several corbels.

[0017] On the basis of the above technical solution, the height of the floating box top plate is the same as the height of the top of the outer wall.

[0018] On the basis of the above technical solution, a well hole penetrates through the side wall of the outer wall, and one end of the well hole is located on the inner wall of the outer wall.

[0019] Compared with the prior art, the advantages of the present invention are as follows:

[0020] 1. The gravity of the floating box bottom die itself and the gravity of the concrete poured on the top of the floating box bottom die both generate downward forces on the floating box bottom die. Compared with the existing top plate supported only by corbels, the water inside the anchor block generates an upward buoyancy force on the floating box bottom die in this construction method, which can reduce the load on the corbels. Since the corbels are designed on the inner wall of the anchor block outer wall, if the load is too large, it may cause the corbels to fall off, thus causing the top plate to fall off and resulting in a construction safety accident. Therefore, this construction method can improve the construction safety.

[0021] 2. Compared with the existing precast beam + precast slab method, since the anchor block size is generally relatively large, the precast beams and precast slabs need to be hoisted one by one to the top of the outer wall of the anchor block for installation. Therefore, the construction period for the installation of precast beams and precast slabs is relatively long. Compared with the existing steel pipe column support method, a large number of steel pipes need to be erected from the bottom of the anchor block in the steel pipe column support method. Therefore, the construction period of this method is relatively long. Since the floating box type bottom formwork can be hoisted as a whole to the top of the outer wall of the anchor block and can be directly fixed to the corbels on the outer wall of the anchor block, the installation of the floating box type bottom formwork is more convenient. Therefore, this construction method can improve the construction efficiency and reduce the construction period.

[0022] 3. When the floating box type bottom formwork is used for the construction of the top slab of the closed structure, the structure of the bottom formwork is simple, and the steel consumption for fabricating the floating box type bottom formwork is greatly reduced compared with the conventional scheme. Therefore, this construction method can reduce the steel consumption and save the material cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is a flow chart of the bottom formwork construction method for the top slab of the closed structure in an embodiment of the present invention;

[0024] Figure 2 is a front view of the bottom formwork of the top slab of the closed structure in an embodiment of the present invention;

[0025] Figure 3 is a left view of the bottom formwork of the top slab of the closed structure in an embodiment of the present invention;

[0026] Figure 4 is a top view of the bottom formwork of the top slab of the closed structure in an embodiment of the present invention;

[0027] Figure 5 is a cross-sectional view of the overall structure in an embodiment of the present invention.

[0028] In the drawings: 1 - floating box side plate, 2 - truss, 3 - floating box partition, 4 - floating box top plate, 5 - floating box top plate rib, 6 - floating box bottom plate rib, 7 - floating box bottom plate, 8 - floating box partition rib, 9 - floating box side plate rib, 10 - corbel, 11 - outer wall, 12 - floating box type bottom formwork. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0029] The present invention will be further described in detail below with reference to the drawings and embodiments.

[0030] See Figure 1 As shown, the bottom formwork construction method for the top slab of the closed structure in an embodiment of the present invention includes the following steps:

[0031] S1: Fix the floating box type bottom formwork 12 to the corbel 10 inside the anchor block (the anchor block is a hollow structure) to prevent the floating box type bottom formwork 12 from falling. The top height of the floating box type bottom formwork 12 is the same as the height of the outer wall 11 of the anchor block, so that the concrete for pouring the top of the anchor block subsequently is on the same horizontal line;

[0032] S2: Inject water into the interior of the anchor block through the wellhole. When the water level reaches the height of the outer wall 11, stop injecting water. At this time, the water generates an upward buoyancy force on the floating box - type bottom formwork 12, and this upward buoyancy load is borne by the corbel 10.

[0033] S3: Tie steel bars on the top of the floating box - type bottom formwork 12 and carry out the first - layer concrete pouring work. After the concrete load offsets the buoyancy force of the floating box - type bottom formwork 12, the corbel 10 will bear the downward force after offset.

[0034] S4: Pump out the water inside the anchor block through the wellhole. When the water level reaches the design elevation, stop pumping, and finally seal the wellhole.

[0035] It can be seen that the self - gravity of the floating box - type bottom formwork 12 of the present invention and the gravity of the concrete poured on the top of the floating box - type bottom formwork 12 both generate downward forces on the floating box - type bottom formwork 12. Compared with the existing top plate that is only supported by the corbel 10, in this construction method, the water inside the anchor block generates an upward buoyancy force on the floating box - type bottom formwork 12, which can reduce the load on the corbel 10. Since the corbel 10 is designed on the inner wall of the outer wall 11 of the anchor block, if the load is too large, it may cause the corbel 10 to fall off, resulting in the top plate falling off and causing a construction safety accident. Therefore, this construction method can improve the construction safety.

[0036] Compared with the existing precast beam + precast slab method, since the size of the anchor block is generally relatively large, the precast beams and precast slabs need to be hoisted one by one to the top of the outer wall 11 of the anchor block for installation, so the construction period for the installation of precast beams and precast slabs is relatively long; compared with the existing steel pipe column support method, the steel pipe column support method requires a large number of steel pipes to be erected from the bottom of the anchor block, and then the top plate is erected based on the steel pipes, so the construction period of this method is relatively long. Since the floating box - type bottom formwork 12 can be hoisted as a whole to the top of the outer wall 11 of the anchor block and can be directly fixed to the corbel 10 of the outer wall 11 of the anchor block, and the installation of the corbel 10 only needs to be connected to the embedded parts inside the outer wall 11, the installation period of this work is very short. Therefore, the installation of the floating box - type bottom formwork 12 is more convenient, and thus this construction method can improve the construction efficiency and reduce the construction period.

[0037] When the floating box - type bottom formwork 12 is used as the top plate for the anchor block capping construction, the structure of this bottom formwork is simple. Compared with the conventional scheme for fabricating the floating box - type bottom formwork 12, the steel consumption is greatly reduced. Therefore, this construction method can reduce the steel usage and save material costs.

[0038] Preferably, before fixing the floating box - type bottom formwork 12 to the corbel 10 in S1, it specifically includes the following steps: fabricate the floating box - type bottom formwork 12 and transport it to the construction site. The floating box - type bottom formwork 12 is not an existing technology and is a technology that is difficult for those skilled in the art to think of.

[0039] The benefit of such a design is that the pontoon bottom formwork 12 needs to be subjected to the buoyancy of water, so the pontoon bottom formwork 12 is sealed, and the pontoon bottom formwork 12 needs to be hoisted into the inside of the anchor. Compared with hoisting the components of the pontoon bottom formwork one by one, hoisting the completed pontoon bottom formwork 12 as a whole can improve construction efficiency. Therefore, before the pontoon bottom formwork 12 is fixed to the corbel 10, the pontoon bottom formwork 12 is completed and then hoisted to improve construction efficiency and shorten the construction period.

[0040] Preferably, see Figure 1 As shown, before fixing the buoyancy box bottom form 12 and the corbel 10 in S1 , the following steps are specifically included: constructing the exterior wall 11 , burying the embedded parts, and installing the corbel 10 .

[0041] The benefit of such a design is that, in order to facilitate the installation of the corbel 10 , the embedded parts need to be buried in advance during the construction of the exterior wall 11 , so as to avoid secondary construction of the exterior wall 11 due to the need to install the corbel 10 after the exterior wall 11 is completed, which may damage the structure of the exterior wall 11 .

[0042] Preferably, see Figure 1 As shown, after S3 and before S4, the following steps are specifically included: after the first layer of concrete reaches the design strength, continue to construct the remaining concrete in layers to the design elevation.

[0043] The benefit of such a design is that: because the thickness of concrete to be poured on the top of the anchor is relatively large, if it is not poured in layers but poured in one go, the pontoon-type bottom formwork 12 and the corbel 10 will be subjected to excessive load, resulting in damage to the pontoon-type bottom formwork 12 and the corbel 10, which may cause construction safety accidents; but if it is poured in layers, due to the high rigidity of the concrete structure, the load of the second layer of concrete poured will be mainly borne by the first layer of concrete, and the pontoon-type bottom formwork 12 and the corbel 10 will not bear too much force from the second layer of concrete poured. Therefore, during the concrete pouring construction, it is necessary to pour in stages.

[0044] The bottom mold of the closed structure top plate in the embodiment of the present invention is shown in FIG. Figure 2 As shown, it includes a pontoon bottom plate 7, a pontoon side plate 1 and a pontoon top plate 4. The surface of the pontoon bottom plate 7 is parallel to the surface of the pontoon top plate 4. The pontoon top plate 4 is arranged on the top of the pontoon bottom plate 7. The pontoon bottom plate 7 and the pontoon top plate 4 are fixed by the pontoon side plate 1.

[0045] The benefit of such a design is that the pontoon bottom mold 12 needs to be subject to the buoyancy of water, so the pontoon bottom mold 12 is a closed structure, and thus the pontoon bottom mold 12 needs to be designed as a whole, consisting of a pontoon bottom plate 7, a pontoon side plate 1 and a pontoon top plate 4 to form a closed structure.

[0046] Preferably, see Figure 2 and Figure 3As shown, several pontoon bottom plate ribs 6 are provided on the top surface of the pontoon bottom plate 7, several pontoon top plate ribs 5 are provided on the bottom surface of the pontoon top plate 4, and several pontoon side plate ribs 9 are provided on the inner side of the pontoon side plate 1.

[0047] The advantage of such a design is that: channel steel is used as the rib plate on the surface of the pontoon top plate 4, and angle steel is used as the rib plate on the surfaces of the pontoon side plate 1 and the pontoon bottom plate 7, which can enhance the overall stiffness of the pontoon bottom formwork 12 and ensure that the pontoon bottom formwork 12 does not undergo local damage under the action of loads.

[0048] Preferably, as shown in Figure 2 and Figure 4 several pontoon partition plates 3 are provided between the pontoon bottom plate 7 and the pontoon top plate 4, pontoon partition plate ribs 8 are provided on both sides of the pontoon partition plates 3, and a truss 2 is provided between adjacent pontoon partition plates 3.

[0049] The advantage of such a design is that: the pontoon partition plates 3, the pontoon partition plate ribs 8 and the truss 2 can improve the overall bending resistance of the pontoon bottom formwork 12 and reduce its deformation under the action of construction loads and buoyancy.

[0050] Preferably, as shown in Figure 5 the pontoon side plate 1 is fixed to the inner wall of the outer wall 11 through several brackets 10.

[0051] The advantage of such a design is that: since the inside of the anchor is a hollow structure, in order to prevent the pontoon bottom formwork 12 from falling after being moved to the designated position, brackets 10 need to be provided to fix the pontoon bottom formwork 12 to the outer wall 11.

[0052] Preferably, as shown in Figure 5 the height of the pontoon top plate 4 is the same as the height of the top of the outer wall 11.

[0053] The advantage of such a design is that: after the pontoon bottom formwork 12 is fixed, concrete pouring work needs to be carried out on the top of the pontoon bottom formwork 12, and the concrete for the pouring work will also cover the top surface of the outer wall 11. In order to avoid affecting the formed concrete building, the height of the pontoon top plate 4 is the same as the height of the top of the outer wall 11, so that the concrete poured on the top is on the same horizontal line.

[0054] Preferably, well holes penetrate through the side wall of the outer wall 11, and one end of the well hole is located on the inner wall of the outer wall 11.

[0055]

[0055] The advantage of such a design is that: after the pontoon bottom formwork 12 is fixed, it is necessary to inject water into and pump water out of the anchor. Also, because the anchor is a sealed structure, well holes need to penetrate through the outer wall 11 to achieve the work of injecting water and pumping water.

[0056] The present invention is not limited to the above embodiments. For those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and modifications can be made, and these improvements and modifications are also considered within the protection scope of the present invention. The content not described in detail in this specification belongs to the prior art well-known to those skilled in the art.

Claims

1. A method for constructing a bottom formwork of a closed structure roof, characterized in that: The method comprises the following steps: A pontoon-type bottom formwork (12) is fixed inside the anchor, and the top height of the pontoon-type bottom formwork (12) is substantially the same as the height of the outer wall (11) of the anchor; water is poured into the anchor until the water height is substantially the same as the height of the outer wall (11); after concrete is poured on the top of the pontoon-type bottom formwork (12), the water inside the anchor is pumped out.

2. The method for constructing the bottom formwork of the closed structure roof according to claim 1, characterized in that: Before fixing the buoyancy box bottom form (12) inside the anchor, the process specifically includes the following steps: making the buoyancy box bottom form (12).

3. The method for constructing the bottom formwork of the closed structure roof according to claim 1, characterized in that: Before fixing the buoyancy box bottom formwork (12) inside the anchor, the following steps are specifically included: installing a mechanism for fixing the buoyancy box bottom formwork (12) on the inner wall of the outer wall (11).

4. The method for constructing the bottom formwork of the closed structure roof according to claim 1, wherein: The concrete pouring process on the top of the pontoon-type bottom form (12) specifically includes the following steps: pouring concrete in layers according to the bearing capacity of the pontoon-type bottom form (12), and pouring subsequent concrete after the previous layer of concrete solidifies.

5. A bottom mold of a closed structure top plate, comprising a pontoon-type bottom mold (12), wherein the pontoon-type bottom mold (12) is composed of a pontoon bottom plate (7), a pontoon side plate (1) and a pontoon top plate (4) to form a closed structure, characterized in that: The surface of the pontoon bottom plate (7) is parallel to the surface of the pontoon top plate (4), the pontoon top plate (4) is arranged on the top of the pontoon bottom plate (7), and the pontoon bottom plate (7) and the pontoon top plate (4) are fixed by the pontoon side plate (1); The pontoon side plate (1) is fixed to the inner wall of the outer wall (11) via a plurality of corbels (10).

6. The bottom mold of the closed structure top plate according to claim 5, characterized in that: The top surface of the pontoon bottom plate (7) is provided with a plurality of pontoon bottom plate ribs (6), the bottom surface of the pontoon top plate (4) is provided with a plurality of pontoon top plate ribs (5), and the inner side of the pontoon side plate (1) is provided with a plurality of pontoon side plate ribs (9).

7. The bottom mold of the closed structure top plate according to claim 6, characterized in that: A plurality of pontoon baffles (3) are provided between the pontoon bottom plate (7) and the pontoon top plate (4), pontoon baffle ribs (8) are provided on both sides of the pontoon baffles (3), and a plurality of trusses (2) are provided between adjacent pontoon baffles (3).

8. The bottom mold of the closed structure roof according to claim 5, characterized in that: The height of the pontoon top plate (4) is the same as the height of the top of the outer wall (11).

9. The bottom mold of the closed structure top plate according to claim 8, characterized in that: A well hole is penetrated through the side wall of the outer wall (11), and one end of the well hole is located on the inner wall of the outer wall (11).

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