Internal mold device for cast-in-place hollow slab bridge

Abstract

The utility model relates to an internal mould device for a cast-in-place hollow slab bridge, which belongs to the technical field of bridge construction and particularly comprises a plurality of sections of tubular mould bodies which are connected with one another and arranged in a hollow slab bridge framework, microflutes are arranged on the outer surfaces of the tubular mould bodies, glass fiber gridding cloth is further laid outside the tubular mould bodies, and the glass fiber gridding cloth is arranged on the outer surfaces of the tubular mould bodies. A gravity anchoring plate steel plate is arranged at the bottom of the tubular die body, the gravity anchoring plate steel plate is fixed to a hollow slab bridge framework and connected with the tubular die body through bolts, a U-shaped steel bar is further arranged on the upper portion of the tubular die body, the tubular die body is wrapped with the U-shaped steel bar, and the U-shaped steel bar is connected with the gravity anchoring plate steel plate through bolts. The U-shaped reinforced concrete hollow slab bridge is simple in structure, reasonable in design, low in construction difficulty, low in cost and suitable for construction of hollow slab bridges with small section heights.

Description

Technical Field

[0001] This utility model relates to an internal formwork device for cast-in-place hollow slab bridges, belonging to the field of bridge construction technology. Background Technology

[0002] In bridge design, when the beam height is limited by factors such as flood control, clearance, and aesthetics, hollow slab beams can effectively reduce self-weight, increase bridge span, and improve the aesthetic and economic performance of the bridge design. The internal formwork of cast-in-place hollow slab bridges typically employs structural forms such as air-filled internal formwork, steel formwork, or plastic or composite material internal formwork.

[0003] Hollow slab bridges, due to their relatively small hollow cross-section height, present significant construction challenges and often employ a permanent formwork system after concrete pouring. However, the significant buoyancy during concrete pouring leads to a substantial problem of the formwork floating upwards. Currently, commonly used formwork structures include: air-filled formwork, steel formwork, and plastic or composite material formwork.

[0004] Airbag-type inner molds use inflatable rubber or polymer material airbags, which form a cavity after inflation. After the concrete solidifies, the air is released and the mold is removed. They are lightweight, flexible, and low in cost, but they are easily punctured by sharp objects and leak air, resulting in high construction risks. They also require external support and have poor resistance to lateral pressure from concrete, and are prone to floating.

[0005] Steel inner molds are assembled by bolting or welding to form cavities, offering high rigidity and stability, but their heavy weight increases the load on the bridge structure and is detrimental to structural safety. Furthermore, installation is time-consuming and labor-intensive, and they are poorly adaptable to irregular cross-sections (such as curved bridges and variable cross-sections). The inner molds are permanently retained and cannot be reused, further contributing to their high cost.

[0006] Plastic or composite material inner molds are prefabricated using polystyrene (EPS), PVC, or fiberglass. Some parts can be recycled or permanently retained after pouring. They are lightweight, corrosion-resistant, and can be customized. However, disposable materials (such as EPS) generate construction waste, have poor environmental performance, low load-bearing capacity, are prone to deformation during concrete pouring, and have high costs. Utility Model Content

[0007] To address the technical problems existing in the prior art, this utility model provides an internal formwork device for cast-in-place hollow slab bridges. It has a simple structure, reasonable design, low construction difficulty, and low cost, and is suitable for the construction of hollow slab bridges with small cross-sectional height.

[0008] To achieve the above objectives, the technical solution adopted by this utility model is an internal mold device for cast-in-place hollow slab bridges, comprising multiple interconnected tubular mold sections disposed within the hollow slab bridge frame. The outer surface of the tubular mold sections is provided with microgrooves, and the exterior of the tubular mold sections is also covered with fiberglass mesh. A gravity anchor plate is disposed at the bottom of the tubular mold sections and is fixed to the hollow slab bridge frame. The gravity anchor plate is connected to the tubular mold sections by bolts. A U-shaped steel bar is disposed at the top of the tubular mold sections, and the U-shaped steel bar is wrapped around the exterior of the tubular mold sections, with both sides of the U-shaped steel bar being connected and fixed to the bridge frame.

[0009] Preferably, the tubular mold body is made of plywood, and the surface of the plywood is coated with an anti-permeability coating.

[0010] Preferably, the tubular mold body is further equipped with multiple annular reinforcing steel bars.

[0011] Preferably, the tubular molds are connected by a tenon and mortise structure, and the connection points of the tubular molds are wrapped with prestressed nylon tape, which is connected by stainless steel buckles.

[0012] Compared with the prior art, the present invention has the following technical effects: the tubular mold made of plywood is easy to form, lightweight, and can work together with the main structure to bear the load, making construction easier, significantly shortening the construction cycle, and reducing construction costs. It also effectively solves the problems of hollow slab beams, which have small hollow cross sections, making construction difficult, and traditional airbag inner molds, steel formwork, plastic or composite material inner molds, which have high construction risks, high costs, and poor environmental performance.

[0013] In addition, this utility model has a simple structure, is easy to construct, and is simple and easy to implement, making it suitable for the construction of hollow slab bridges with small cross-sectional height. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the structure of this utility model.

[0015] Figure 2 This is a schematic diagram of the connection structure of the tubular mold body of this utility model. Detailed Implementation

[0016] To make the technical problems, technical solutions, and beneficial effects of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present utility model and are not intended to limit the present utility model.

[0017] like Figure 1 , Figure 2As shown, an internal mold device for cast-in-place hollow slab bridges includes multiple interconnected tubular mold bodies 2 disposed within the hollow slab bridge frame 1. The outer surface of the tubular mold bodies 2 is provided with microgrooves, and the exterior of the tubular mold bodies 2 is also covered with fiberglass mesh. A gravity anchor plate 3 is disposed at the bottom of the tubular mold bodies 2 and is fixed to the hollow slab bridge frame 1. The gravity anchor plate 3 is connected to the tubular mold bodies 2 by bolts 4. A U-shaped steel bar 5 is disposed at the upper part of the tubular mold bodies 2. The U-shaped steel bar 5 is wrapped around the exterior of the tubular mold bodies 1, and both sides of the U-shaped steel bar 5 are connected and fixed to the bridge frame 1.

[0018] The tubular mold 1 of this invention is made of plywood, and the surface of the plywood is coated with an anti-seepage coating. The anti-seepage coating is made of a composite liquid of water-based epoxy resin and nano-montmorillonite, forming an anti-seepage barrier and improving corrosion resistance. Microgrooves are pre-etched on the surface of the tubular mold 1 at 5mm intervals and 2mm depth. During pouring, the concrete seeps into the microgrooves to form a "mortise and tenon" mechanical interlocking. Fiberglass mesh is laid on the interface between the tubular mold 1 and the concrete to enhance the shear strength of the interface. The tubular molds 1 are connected by a mortise and tenon structure. The joints of the tubular molds 1 are wrapped with prestressed nylon strips 6, which are connected by stainless steel clips 7, satisfying splicing requirements while preventing grout leakage at the joints during concrete pouring. Ring-shaped reinforcing steel bars 8 are embedded inside the tubular mold 1 at 1m intervals to prevent deformation of the inner mold during concrete pouring. U-shaped steel bars 5 are installed on the outside of the tubular mold 1 and welded to the top and bottom slab steel bars of the beam to prevent lateral displacement of the wooden mold during pouring and to improve the shear capacity of the beam. A gravity anchor plate 3 is installed at the bottom of the tubular mold 1 and bolted to the tubular mold 1. The gravity anchor plate 3 is welded to the beam reinforcement to enhance the anti-buoyancy of the inner mold.

[0019] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present utility model shall be included within the scope of the present utility model.

Claims

1. An inner mold device for cast-in-place hollow slab bridges, characterized in that: The system includes multiple interconnected tubular mold sections housed within a hollow slab bridge frame. The outer surface of each tubular mold section has microgrooves, and a fiberglass mesh is laid on its exterior. A gravity anchor plate is installed at the bottom of each tubular mold section and is fixed to the hollow slab bridge frame. The gravity anchor plate is connected to the tubular mold section by bolts. U-shaped reinforcing bars are installed at the top of each tubular mold section, wrapping around the exterior of the tubular mold section and connecting and fixing both sides of the U-shaped reinforcing bars to the bridge frame.

2. The inner mold device for cast-in-place hollow slab bridges according to claim 1, characterized in that: The tubular mold body is made of plywood, and the surface of the plywood is coated with an anti-seepage coating.

3. The inner mold device for cast-in-place hollow slab bridges according to claim 1, characterized in that: The tubular mold body is also equipped with multiple annular reinforcing steel bars.

4. The inner mold device for cast-in-place hollow slab bridges according to claim 1, characterized in that: The tubular molds are connected by mortise and tenon joints, and the joints of the tubular molds are wrapped with prestressed nylon tape, which is connected by stainless steel buckles.

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