Inner mold structure of expressway box girder

Abstract

An expressway box girder internal mold structure comprises a first standard mold section, a first variable slope mold section, a second variable slope mold section and a second standard mold section. The first standard mold section, the first variable slope mold section, the second variable slope mold section and the second standard mold section are sequentially arranged and integrally formed to form a box girder notch section template; the first standard mold section and the second standard mold section are horizontally arranged, the first variable slope mold section and the second variable slope mold section are obliquely arranged, and the included angle between the second variable slope mold section and the second standard mold section and the included angle between the first variable slope mold section and the second variable slope mold section are both larger than 90 degrees. According to the expressway box girder internal mold structure, the mold removal difficulty is greatly reduced, and the working efficiency is improved.

Description

Technical Field

[0001] This utility model relates to box girders, and in particular to an internal formwork structure for a highway box girder. Background Technology

[0002] In the prefabrication of box girders in highway beam yards, prefabricated box girders are typically tensioned using both positive and negative moments. After prefabrication, positive moment tensioning is applied, followed by negative moment tensioning after the girder is erected. However, during prefabrication, a negative moment tensioning slot needs to be pre-reserved within the cavity of the prefabricated box girder, with the two sides of the slot forming a right angle. In traditional prefabrication, the inner formwork of the box girder must align with the negative moment slot. However, after the box girder is poured, when the inner formwork is pulled outwards, it is blocked by the negative moment tensioning slot, causing it to become stuck and unable to be removed normally. Forcibly removing it will damage the concrete at the slot. Utility Model Content

[0003] The technical problem to be solved by this utility model is to provide an inner formwork structure for a highway box girder. By adjusting the inner formwork of the box girder, while ensuring that the precast box girder can undergo normal positive and negative bending moment tension in the later stage, the inner formwork of the box girder can be easily and safely extracted from the cavity of the precast box girder after the precast box girder is poured in the early stage, saving manpower and resources and reducing the difficulty of formwork construction.

[0004] To solve the above-mentioned technical problems, the technical solution adopted by this utility model is as follows:

[0005] A box girder internal formwork structure for highways includes a first standard formwork segment, a first variable slope formwork segment, a second variable slope formwork segment, and a second standard formwork segment. The first standard formwork segment, the first variable slope formwork segment, the second variable slope formwork segment, and the second standard formwork segment are arranged sequentially and integrally formed to constitute the box girder slot section template. The first standard formwork segment and the second standard formwork segment are arranged horizontally, while the first variable slope formwork segment and the second variable slope formwork segment are arranged at an angle, and the included angle between the second variable slope formwork segment and the second standard formwork segment, and the included angle between the first variable slope formwork segment and the second variable slope formwork segment are all greater than 90 degrees.

[0006] The template for the slot section of the box girder is made of steel.

[0007] The included angle between the first slope section and the second slope section is between 140° and 160°.

[0008] The angle between the second variable slope section and the second standard section is between 150° and 170°.

[0009] The template of the box girder slot section is equipped with vertical connecting rod support components and horizontal connecting rod support components.

[0010] The vertical connecting rod support assembly includes at least one set of vertical connecting rods. The upper and lower ends of the vertical connecting rods are respectively connected to a top support and a base. The top support and the base are fixedly connected to the first support by bolts. The first support at the upper end is fixed to the bottom surface of the template of the box girder slot section, and the first support at the lower end is fixed to the top surface of the support.

[0011] The transverse link support assembly includes a transverse link, which is arranged crosswise with the vertical link and connected to each other at the cross nodes; a second support is installed at both ends of the transverse link, and the second support is fixed on the template of the box girder slot section.

[0012] This utility model provides an inner mold structure for a highway box girder, which has the following technical advantages:

[0013] 1) The original design of the box girder slot section template (box girder inner formwork) was perpendicular to the top slab of the precast box girder, forming a 90-degree right angle. When the box girder inner formwork was removed, the right angle formed by the precast box girder slot after casting and the right angle of the box girder inner formwork would affect each other, making demolding difficult. After optimization and modification, the right angle template of the box girder inner formwork was enlarged and adjusted to an obtuse angle template. This creates enough space for the box girder inner formwork to be removed smoothly, reducing the difficulty of template disassembly and speeding up the disassembly speed.

[0014] 2) Changes in the angle of the slot template will not affect the subsequent negative bending moment prestressing construction, and will ensure the integrity of the concrete at the slot of the box girder cavity, preventing damage to the slot concrete caused by collisions during demolding. Attached Figure Description

[0015] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0016] Figure 1 This is the front view of the existing box girder inner formwork.

[0017] Figure 2 This is the front view of the inner mold of the box girder of this utility model.

[0018] Figure 3 This is a schematic diagram (first type) of the vertical connecting rod support assembly in this utility model.

[0019] Figure 4 This is a schematic diagram (second type) of the vertical connecting rod support assembly in this utility model.

[0020] Figure 5 This is a simplified diagram of the template in this utility model.

[0021] In the figure: First standard module segment 1, first variable slope module segment 2, second variable slope module segment 3 and second standard module segment 4, vertical connecting rod support assembly 5, and horizontal connecting rod support assembly 6. Detailed Implementation

[0022] like Figure 2 As shown, a type of inner formwork structure for a highway box girder includes a first standard formwork section 1, a first variable slope formwork section 2, a second variable slope formwork section 3, and a second standard formwork section 4. The first standard formwork section 1, the first variable slope formwork section 2, the second variable slope formwork section 3, and the second standard formwork section 4 are arranged sequentially and integrally formed to constitute the box girder slot section template. The first standard formwork section 1 and the second standard formwork section 4 are arranged horizontally, while the first variable slope formwork section 2 and the second variable slope formwork section 3 are arranged at an angle, with the included angle between the second variable slope formwork section 3 and the second standard formwork section 4, and the included angle between the first variable slope formwork section 2 and the second variable slope formwork section 3, both greater than 90 degrees. The inner formwork of the box girder cavity is installed in place, meeting the construction requirements of the original design drawings. After the box girder template is installed, the precast box girder is poured. After pouring, because the inner formwork of the box girder (box girder slot section template) is not perpendicular to the negative bending moment tension slot of the precast box girder, the inner formwork of the box girder can be easily extracted from the precast box girder (extraction direction is indicated by the arrow). After the inner formwork of the box girder was adjusted, the difficulty of demolding was greatly reduced, work efficiency was improved, and human resources were saved.

[0023] The angle of the steel formwork for the slot section of the box girder is optimized and adjusted so that there is enough space in the cavity when the inner formwork is disassembled after the concrete is poured, so that the inner formwork can be smoothly pulled out of the box girder cavity without damaging the slot concrete.

[0024] The formwork for the slot section of the box girder is bolted to the formwork for the inner section of the box girder.

[0025] like Figure 2 As shown, the included angle between the first variable slope section 2 and the second variable slope section 3 is between 140° and 160°. Tests have proven that within this angle range, the requirements for negative bending moment tensioning can be guaranteed, while the resistance to formwork removal after casting the box girder is relatively small.

[0026] like Figure 2 As shown, the included angle between the second variable slope section 3 and the second standard section 4 is between 150° and 170°. Tests have proven that within this angle range, the requirements for negative bending moment tensioning can be guaranteed, while the resistance to formwork removal after casting the box girder is relatively small.

[0027] like Figure 2 As shown, vertical connecting rod support assembly 5 and horizontal connecting rod support assembly 6 are arranged inside the template of the box girder slot section. Both the vertical connecting rod support assembly 5 and the horizontal connecting rod support assembly 6 are connected to the main keel of the template.

[0028] like Figure 2As shown, the transverse linkage support assembly 6 includes a transverse linkage 6.1, which is arranged crosswise with the vertical linkage 5.1 and connected to each other at the intersection nodes. Second supports 6.2 are installed at both ends of the transverse linkage 6.1, and the second supports 6.2 are fixed to the main keel of the box girder slot section formwork via connectors. The second supports 6.2 are connected to other standard stage formwork via bolts. The transverse linkage support assembly 6 transmits the lateral concrete pressure of the box girder slot section formwork. The transverse linkage support assembly 6 is crosswise connected to the vertical linkage support assembly 5, forming a spatial grid structure at the intersection nodes via bolts, which improves the overall rigidity.

[0029] like Figure 3 As shown, the vertical connecting rod support assembly 5 includes at least one set of vertical connecting rods 5.1, which can be one set, two sets, or three sets. Adjacent vertical connecting rods 5.1 are connected as a whole by bolts. A top support 5.3 and a base 5.4 are respectively connected to the upper and lower ends of the vertical connecting rods 5.1. The top support 5.3 and the base 5.4 are fixedly connected to the first support 5.2 by bolts. The upper first support 5.2 is fixed to the bottom surface of the main keel of the box girder slot section formwork, and the lower first support 5.2 is fixed to the top surface of the support 5.5. The support 5.5 can be a hardened concrete surface or a temporary support platform to ensure the load transfer path. The vertical connecting rod support assembly 5 directly bears the weight of the box girder slot section formwork and concrete.

[0030] like Figure 4 As shown, when there are multiple sets of vertical connecting rods 5.1, such as three sets in this embodiment, the extra intermediate connecting rods mainly serve to adjust the length of the box girder connecting rods. The reason for setting three sets of connecting holes is that the size of the box girder cavity space is not fixed, and the length of the connecting rods needs to be adjusted in some positions, thereby achieving the function of adjusting the inner mold space.

[0031] The vertical connecting rod support assembly 5 and the horizontal connecting rod support assembly 6 are bolted together at their intersections to form a spatial force-bearing system. The vertical connecting rod support assembly 5 and the horizontal connecting rod support assembly 6 serve to complement each other spatially, provide load transfer paths, and coordinate deformation control. The horizontal connecting rods constrain the outward expansion of the formwork, while the vertical connecting rods resist the settlement of the formwork, forming a composite structure of "horizontal compression resistance and vertical load bearing." The lateral pressure of the concrete is transferred to the horizontal connecting rods, and then to the vertical connecting rods through the nodes, ultimately borne by the support system. Moreover, both components together restrict the translation and rotation of the formwork, reducing the risk of joint misalignment during the pouring process.

[0032] The combination of vertical connecting rod support component 5 and horizontal connecting rod support component 6 enhances the overall stability of the formwork, ensures forming accuracy (by adjusting the spacing between the horizontal and vertical connecting rods (typically horizontal rod spacing ≤ 1.5m, vertical rod spacing ≤ 2m), precisely controls the width, height, and wall thickness of the box girder cavity (error ≤ 3mm), reduces the probability of grout leakage at joints, and ensures the smoothness of the concrete surface), improves construction efficiency (compared to traditional welding, efficiency is increased by more than 40%; for variable cross-section box girders, the number or position of connecting rods can be increased or decreased to flexibly adapt to the formwork requirements of different sections), and reduces overall costs.

[0033] By rationally arranging the members (such as using triangular stabilizing trusses), the amount of steel used can be reduced (by about 15-20%) while ensuring strength. Standardized connecting rods and hinges are used together, and the internal formwork system can be reused more than 50 times, reducing the cost of a single construction project. Safety and durability are also improved (the load is distributed and transferred in multiple directions by the members, avoiding stress concentration, extending the life of the connection nodes, and damaged individual members can be quickly replaced without the need for overall formwork dismantling, reducing downtime).

Claims

1. An inner formwork structure for a highway box girder, characterized in that: It includes a first standard module segment (1), a first variable slope module segment (2), a second variable slope module segment (3), and a second standard module segment (4); the first standard module segment (1), the first variable slope module segment (2), the second variable slope module segment (3), and the second standard module segment (4) are arranged in sequence and integrally formed to form the box girder slot section template; the first standard module segment (1) and the second standard module segment (4) are arranged horizontally, the first variable slope module segment (2) and the second variable slope module segment (3) are arranged at an angle, and the included angle between the second variable slope module segment (3) and the second standard module segment (4) and the included angle between the first variable slope module segment (2) and the second variable slope module segment (3) are both greater than 90 degrees.

2. The inner formwork structure for a highway box girder according to claim 1, characterized in that: The template for the slot section of the box girder is made of steel.

3. The inner formwork structure for a highway box girder according to claim 2, characterized in that: The included angle between the first slope section (2) and the second slope section (3) is between 140° and 160°.

4. The inner formwork structure for a highway box girder according to claim 3, characterized in that: The angle between the second variable slope section (3) and the second standard section (4) is between 150° and 170°.

5. The inner formwork structure for a highway box girder according to claim 4, characterized in that: The template of the box girder slot section is equipped with a vertical connecting rod support assembly (5) and a horizontal connecting rod support assembly (6).

6. The inner formwork structure for a highway box girder according to claim 5, characterized in that: The vertical connecting rod support assembly (5) includes at least one set of vertical connecting rods (5.1). The upper and lower ends of the vertical connecting rods (5.1) are respectively connected to a top support (5.3) and a base (5.4). The top support (5.3) and the base (5.4) are fixedly connected to the first support (5.2) by bolts. The upper first support (5.2) is fixed on the bottom surface of the template of the box girder slot section, and the lower first support (5.2) is fixed on the top surface of the support (5.5).

7. The inner formwork structure for a highway box girder according to claim 5, characterized in that: The transverse link support assembly (6) includes a transverse link (6.1), which is arranged crosswise with the vertical link (5.1) and connected to each other at the cross nodes; the transverse link (6.1) is equipped with a second support (6.2) at both ends, and the second support (6.2) is fixed on the template of the box girder slot section.

Images