Composite construction method for enhancing integrity of bridge deck slab

Abstract

The invention relates to a composite construction method for enhancing the integrity of a bridge deck slab, which comprises the following steps of: welding double-layer shear nails at the joint of a prefabricated bottom-layer bridge deck slab and a steel main beam, sequentially mounting a ribbed steel template, a bottom-layer bridge deck slab steel bar truss, longitudinal steel bars and through steel bars, and pouring concrete to obtain the bottom-layer bridge deck slab; connecting the bottom-layer bridge deck with the steel main beam, enabling the bottom-layer bridge deck and the steel main beam to form a pi-shaped structure, hoisting the pi-shaped structure to the cover beam, and pouring concrete until the overall height of the bridge deck is met. Compared with the prior art, the overall performance of the steel plate composite beam bridge deck slab can be guaranteed by prefabricating and installing the bottom layer bridge deck slab and then adopting cast-in-place, and the long-term durability of the steel plate composite beam bridge deck slab is improved. The two construction methods of prefabrication and installation and the permanent formwork are fused, the overall performance of the steel plate composite beam is enhanced, the integrality and durability of the bridge deck slab are greatly improved compared with prefabrication and assembly construction, the steel consumption is greatly reduced compared with permanent formwork construction, and the economical efficiency is improved.

Description

Technical Field

[0001] The invention relates to the technical field of bridge structure and construction, and in particular to a composite construction method for enhancing the integrity of a bridge deck. Background Art

[0002] Steel plate composite beams combine steel structures with concrete bridge decks, giving full play to the performance advantages of the two materials. On the basis of ensuring the bearing capacity of the structure, it greatly reduces the weight of the bridge and increases the componentization rate of the bridge, which is conducive to the bridge construction industry's advancement towards the goal of industrialization.

[0003] During the construction of ordinary steel-concrete composite continuous beam bridges, the bridge deck is generally prefabricated in sections along the longitudinal direction of the bridge, and then installed and the joint concrete is poured again on site. In order to improve the connection strength of the wet joint and enhance the integrity of the structure, the engineers designed structural forms such as the rotating steel bar joint, which increased the overall force of the bridge deck to a certain extent. However, the joint between the wet joint and the prefabricated bridge deck still exists, and under the action of long-term vehicle fatigue loads, cracks in the bridge deck frequently occur. In addition, shear nails are usually set at the wet joint position. When the wet joint reinforcement is arranged on site, it is often interfered by the shear nails on the steel main beam, which greatly affects the efficiency of on-site construction.

[0004] In addition, the construction methods of prefabrication and permanent formwork are currently commonly used in large-volume concrete structures. The former is constructed by splitting the target component into multiple relatively regular small components, prefabricating them in the factory and then assembling them on site. The prefabrication construction method greatly reduces the workload on the construction site during the construction process and improves the overall construction efficiency. However, since the prefabricated components are subsequently connected together through post-processing methods such as wet joints and prestressing, the overall performance of the structure is affected and its long-term durability is challenged. The latter is constructed by establishing a permanent formwork structure with greater rigidity on the main load-bearing structure of the bridge, generally using steel or higher-grade concrete. This construction method can also reduce the impact of on-site construction on the surrounding environment, but the permanent steel formwork of the entire bridge will bring a great burden to the economy of the project. Summary of the invention

[0005] The purpose of the present invention is to overcome the defects of the above-mentioned prior art and provide a composite construction method for enhancing the integrity of the bridge deck. It can enhance the overall performance of the steel plate composite beam while ensuring that the construction site has little impact on the surrounding environment, and greatly increase the integrity and durability of the bridge deck. Compared with permanent formwork construction, it greatly reduces the amount of steel used and improves the economy.

[0006] The purpose of the present invention can be achieved by the following technical solutions:

[0007] The present invention provides a composite construction method for enhancing the integrity of a bridge deck, comprising the following steps:

[0008] S1: Weld double-layer shear studs at the connection between the prefabricated bottom deck and the steel main beam, and install ribbed steel formwork perpendicular to the steel main beam at intervals of the longitudinal length of the prefabricated bottom deck;

[0009] S2: Place the bottom deck steel trusses parallel to the ribbed steel formwork on both sides of the ribbed steel formwork in S1, and place longitudinal steel bars perpendicular to the bottom deck steel trusses at equal intervals in the bottom deck steel trusses;

[0010] S3: Welding through steel bars at preset intervals in the longitudinal steel bars in S2 so that the through steel bars penetrate the entire ribbed steel formwork, and then pouring concrete to obtain the bottom bridge deck, realize the connection between the bottom bridge deck and the steel main beam, and perform maintenance;

[0011] S4: After the strength maintenance of the bottom bridge deck in S3 is completed, the bottom surface and the side surface of the bottom bridge deck are fixedly connected to the ribbed steel formwork respectively, so that the bottom bridge deck and the steel main beam form a π-shaped structure;

[0012] S5: Hoist the π-shaped structure in S4 onto the cap beam, and pour concrete into the ribbed steel formwork, the steel skeleton of the bridge deck, and the upper bridge deck in turn, and then flatten and pour the entire bridge deck until the overall height of the bridge deck is met.

[0013] Furthermore, in S1, the ribbed steel formwork is arranged at intervals from the prefabricated bottom bridge deck, and the bottom bridge decks at both ends of the bridge are prefabricated and installed, and the arrangement is n+m+n+m+n+…+n+m+n,

[0014] Among them, n represents the prefabricated and installed bottom bridge deck; m represents the ribbed steel formwork; + represents the interval.

[0015] Further, in S1, the double-layer shear nails include an upper layer of shear nails and a lower layer of shear nails, and the upper layer of shear nails and the lower layer of shear nails are arranged correspondingly;

[0016] The middle and upper parts of the double-layer shear studs are both raised structures, the middle raised structure is located inside the prefabricated bottom bridge deck, and the upper raised structure is located inside the upper bridge deck.

[0017] Furthermore, in S1, the connection between the ribbed steel formwork and the steel main beam is fixedly connected by ribbed steel formwork fixing bolts, and four ribbed steel formwork fixing bolts are provided. The four ribbed steel formwork fixing bolts are respectively arranged on four corners of the contact surface between the ribbed steel formwork and the steel main beam.

[0018] Further, in S1, the ribbed steel formwork includes a steel bottom plate, a steel side plate and a perforated transverse rib, the perforated transverse rib is welded to the steel bottom plate, and the perforated transverse rib and the steel bottom plate are vertically welded to the steel side plate;

[0019] The thickness of the steel bottom plate and the steel side plate is 3-6 mm, and the thickness of the perforated transverse rib is 9-11 mm;

[0020] The hole spacing on the perforated transverse rib is 290-310 mm, and the hole diameter is larger than the diameter of the penetrating steel bar.

[0021] Furthermore, the steel side plate is fixedly connected to the side edge of the prefabricated bottom bridge deck by using steel side form fixing bolts, and the steel bottom plate is fixedly connected to the bottom surface of the prefabricated bottom bridge deck by using steel bottom plate fixing bolts;

[0022] The steel side plate comprises a steel side plate body and a steel side plate extension, and the length of the steel side plate extension is half of the length of the prefabricated and installed bottom bridge deck;

[0023] The steel bottom plate comprises a steel bottom plate body and a steel bottom plate extension portion, and the length of the steel bottom plate extension portion is 45-55 mm;

[0024] The steel side plate extension and the steel bottom plate extension are both provided with a plurality of holes, and the spacing between the plurality of holes is 400 mm.

[0025] Further, in S2, the bottom bridge deck steel bar truss includes a structural steel bar truss and a connecting steel bar truss, the height of the structural steel bar truss is less than the height of the prefabricated bottom bridge deck, the structural steel bar truss includes an upper layer of steel bars and a lower layer of steel bars, the lower layer of steel bars is located inside the prefabricated bottom bridge deck, and the upper layer of steel bars is reserved on the upper part of the prefabricated bottom bridge deck and cast inside the upper layer of the bridge deck;

[0026] The height of the connecting steel bar truss is greater than the height of the prefabricated bottom bridge deck.

[0027] Further, in S2, the longitudinal steel bars include a top layer of steel bars and a bottom layer of steel bars, the top layer of steel bars are fixedly connected to the upper layer of steel bars, and the bottom layer of steel bars are fixedly connected to the lower layer of steel bars.

[0028] Furthermore, the through steel bars include through steel bars on side a and through steel bars on side b, and the through steel bars on side a and through steel bars on side b alternately pass through the holes of the perforated transverse ribs in the ribbed steel formwork and are arranged on both sides of the ribbed steel formwork in opposite directions.

[0029] Further, in S5, the upper bridge deck is cast as a whole of the whole bridge;

[0030] The ribbed steel formwork is a permanent formwork for the bridge deck and will not be removed after the upper bridge deck is constructed.

[0031] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0032] 1. In the present invention, the bottom bridge deck is prefabricated and installed, and then cast on site, so that the overall performance of the steel plate composite beam bridge deck can be guaranteed and the long-term durability of the steel plate composite beam bridge deck can be improved.

[0033] 2. The present invention integrates the two construction methods of prefabricated installation and permanent formwork, thereby ensuring that the construction site has little impact on the surrounding environment while enhancing the overall performance of the steel plate composite beam. Compared with prefabricated assembly construction, the integrity and durability of the bridge deck are greatly increased, and compared with permanent formwork construction, the amount of steel used is greatly reduced, thereby improving economy.

[0034] 3. The steel bar arrangement inside the bottom bridge deck in the present invention adopts the floor deck steel bar truss, which has highly market-oriented specifications and can be purchased in large quantities, thereby reducing the labor cost during the construction process and improving the engineering efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 A three-dimensional perspective view of a segment bridge deck after construction is completed in Example 1;

[0036] Figure 2 It is a three-dimensional schematic diagram of the arrangement of shear nails of the steel main beam in Example 1;

[0037] Figure 3 A three-dimensional perspective view of the bottom bridge deck reinforcement arrangement in Example 1;

[0038] Figure 4 This is an elevation view of the steel bar arrangement of the bottom deck in Example 1;

[0039] Figure 5 A three-dimensional schematic diagram of the arrangement of the steel formwork and the through-steel bars in Example 1;

[0040] Figure 6 It is an elevation view of the steel formwork and through-steel arrangement in Example 1;

[0041] Figure 7 This is a schematic diagram of the installation of the ribbed steel formwork in Example 1;

[0042] Figure 8 This is a schematic diagram of the structure after the bottom bridge deck is poured in Example 1;

[0043] Fig. 9 This is a schematic diagram of the structure after the upper bridge deck is cast in Example 1.

[0044] Figure 1 Description of the mark in:

[0045] 1-steel main beam, 2-bottom deck, 3-upper deck, 4-ribbed steel formwork, 5-double-layer shear nails, 6-through steel bars, 7-connecting steel bar trusses, 9-perforated transverse ribs, 10-steel side plates;

[0046] Figure 2 Description of the mark in:

[0047] 1-steel main beam, 5-double-layer shear studs;

[0048] Figure 3 Description of the mark in:

[0049] 2- bottom bridge deck, 6a-a side through steel bars, 6b-b side through steel bars, 7- connection steel bar truss, 11- structural steel bar truss, 13- steel bottom plate;

[0050] Figure 4 Description of the mark in:

[0051] 2- bottom bridge deck, 6a- a-side through steel bars, 6b- b-side through steel bars, 7- connecting steel bar truss, 11- structural steel bar truss, 12- longitudinal steel bars;

[0052] Figure 5 Description of the mark in:

[0053] 1-steel main beam, 4-ribbed steel formwork, 5-double-layer shear nails, 6a-a-side through steel bars, 6b-b-side through steel bars, 8a-ribbed steel formwork fixing bolts, 8b-steel side formwork fixing bolts, 8c-steel bottom plate fixing bolts, 9-perforated transverse ribs, 10-steel side plates;

[0054] Figure 6 Description of the mark in:

[0055] 5-double-layer shear nails, 8a-ribbed steel formwork fixing bolts, 8b-steel side formwork fixing bolts, 8c-steel bottom plate fixing bolts, 9-perforated transverse ribs, 10-steel side plates, 13-steel bottom plates;

[0056] Figure 7 Description of the mark in:

[0057] 1-steel main beam, 4-ribbed steel formwork, 5-double-layer shear nails, 8a-ribbed steel formwork fixing bolts, 9-perforated transverse ribs, 13-steel bottom plate;

[0058] Figure 8 Description of the mark in:

[0059] 1-steel main beam, 2-bottom deck, 4-ribbed steel formwork, 5-double-layer shear nails, 6a-a-side through steel bars, 6b-b-side through steel bars, 7-connecting steel bar trusses, 8a-ribbed steel formwork fixing bolts, 8b-steel side formwork fixing bolts, 9-perforated transverse ribs, 10-steel side formwork;

[0060] Fig. 9 Description of the mark in:

[0061] 1- Steel main beam, 2- Bottom deck, 3- Upper deck, 4- Ribbed steel formwork. DETAILED DESCRIPTION

[0062] The specific implementation methods of the present invention are described in detail below through examples. These examples are implemented on the premise of the scheme described in the present invention, and provide detailed implementation methods and specific operating processes, but the protection scope of the present invention is not limited to the following examples.

[0063] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments. Any features such as component models, material names, connection structures, preparation methods, materials, structures or composition ratios not clearly described in this technical solution are deemed to be common technical features disclosed in the prior art.

[0064] Example 1

[0065] This embodiment provides a composite construction method for enhancing the integrity of a bridge deck, comprising the following steps:

[0066] S1: Weld double-layer shear nails 5 at the connection between the prefabricated bottom bridge deck 2 and the steel main beam 1, and install ribbed steel formwork 4 at intervals of the longitudinal length of the prefabricated bottom bridge deck 2 and perpendicular to the steel main beam 1. The double-layer shear nails 5 include upper shear nails and lower shear nails, which are correspondingly arranged, and the ribbed steel formwork 4 is installed perpendicular to the steel main beam 1 at intervals of the longitudinal length of the bottom bridge deck 2.

[0067] like Figure 2 As shown, the middle and upper parts of the double-layer shear nails 5 are both raised structures. The middle raised structure is installed inside the bottom bridge deck 2, and the raised height is 1 / 2 of the thickness of the bottom bridge deck 2; the upper raised structure is installed inside the upper bridge deck 3, and is 1 / 2 of the thickness of the upper bridge deck 3. The welding position of the double-layer shear nails 5 and the steel main beam 1 is located at both ends where the bottom bridge deck 2 and the steel main beam 1 are connected. Five rows of double-layer shear nails 5 are arranged at each end, and six double-layer shear nails 5 are arranged in one row. Three double-layer shear nails 5 are arranged on the wing plates on both sides of the web of the steel main beam 1.

[0068] like Figure 7As shown, the ribbed steel formwork 4 is fixed to the single steel main beam 1 by four ribbed steel formwork fixing bolts 8a, and the four ribbed steel formwork fixing bolts are respectively arranged at the four corners of the contact surface between the ribbed steel formwork 4 and the steel main beam 1.

[0069] like Figure 5 As shown, the ribbed steel formwork 4 includes a steel bottom plate 13, a steel side plate 10, and a perforated transverse rib 9. During the welding process, the perforated transverse rib 9 is preferentially welded vertically to the steel bottom plate 13, and the spacing between each perforated transverse rib 9 is 500 mm, and then the steel side plate 10 is welded to the steel bottom plate 13 and the perforated transverse rib 9, keeping the steel side plate 10 in the center.

[0070] The length of the steel bottom plate 13, i.e. the length of the steel bottom plate 13 along the bridge direction, a1 = (number of perforated transverse ribs - 1) × 500 + 200, unit: mm. The width of the steel bottom plate 13, i.e. the width of the steel bottom plate 13 across the bridge direction, b1 = the actual width of the bridge deck; the length of the steel side plate 10, i.e. the length of the steel side plate 10 along the bridge direction, a2 = the length a1 of the steel bottom plate 13 + the length of the underlying bridge deck 2, the height h1 of the steel side plate 10 = the actual thickness of the bridge deck; the length of the perforated transverse rib 9 b3 = b1, and the height is the same as the thickness of the underlying bridge deck 2. The thickness of the steel bottom plate 13 and the steel side plate 10 are both 5mm, and the thickness of the perforated transverse rib 9 is 10mm. The hole spacing of the perforated transverse rib 9 is 300mm, and the hole diameter is larger than the diameter of the through steel bar 6.

[0071] The ribbed steel formwork 4 is arranged at intervals with the bottom bridge deck 2, and the two ends of the bridge are the bottom bridge deck 2, the bottom bridge deck 2 has a longitudinal length of intervals, and the arrangement is n+m+n+m+n+…+n+m+n,

[0072] Among them, n represents the bottom bridge deck 2; m represents the ribbed steel formwork 4; + represents the interval.

[0073] In order to ensure that the ribbed steel formwork 4 is fully fitted to the underlying bridge deck 2, the steel side plate 10 is fixedly connected to the side of the prefabricated underlying bridge deck 2 using steel side form fixing bolts 8b, and the steel bottom plate 13 is fixedly connected to the bottom surface of the prefabricated underlying bridge deck 2 using steel bottom plate fixing bolts 8c.

[0074] The steel side plate 10 includes a steel side plate body and a steel side plate extension, the length of which is half the length of the prefabricated bottom bridge deck 2; the steel bottom plate 13 includes a steel bottom plate body and a steel bottom plate extension, the length of which is 50 mm. The steel side plate extension and the steel bottom plate extension are both provided with a plurality of holes, and the spacing between the plurality of holes is 400 mm.

[0075] S2: The bottom bridge deck 2 steel trusses parallel to the ribbed steel formwork 4 are placed on both sides of the ribbed steel formwork 4 in S1, and longitudinal steel bars 12 perpendicular to the bottom bridge deck 2 steel trusses are equidistantly placed inside the bottom bridge deck 2 steel trusses.

[0076] like Figure 3 and Figure 4 As shown, the steel bar truss of the bottom bridge deck 2 includes a structural steel bar truss 11 and a connecting steel bar truss 7. The height of the structural steel bar truss 11 is less than the height of the bottom bridge deck 2. The structural steel bar truss 11 includes an upper layer of steel bars and a lower layer of steel bars. The lower layer of steel bars is located inside the prefabricated bottom bridge deck 2. The upper layer of steel bars is reserved on the upper part of the prefabricated bottom bridge deck 2 and cast inside the upper bridge deck 3. The height of the connecting steel bar truss 7 is greater than the height of the bottom bridge deck 2. To further improve construction efficiency, the steel bar truss has the same structure as the steel bar truss inside the floor deck.

[0077] The longitudinal steel bars 12 include a top layer of steel bars and a bottom layer of steel bars. The top layer of steel bars is fixedly connected to the upper layer of steel bars, and the bottom layer of steel bars is fixedly connected to the lower layer of steel bars.

[0078] S3: Welding the through steel bars 6 at a preset interval in the longitudinal steel bars 12 in S2, so that the through steel bars 6 penetrate the entire ribbed steel formwork 4, and then pouring concrete to obtain the bottom bridge deck 2, so as to achieve the connection between the prefabricated bottom bridge deck 2 and the steel main beam 1, and then perform maintenance;

[0079] like Figures 5 to 7 As shown, the through steel bars 6 include through steel bars 6 on the side a and through steel bars 6 on the side b, and the through steel bars 6 on the side a and through steel bars 6 on the side b alternately pass through the holes of the perforated transverse ribs 9 in the ribbed steel formwork 4 and are arranged on both sides of the ribbed steel formwork 4 in opposite directions. Then, the precast bottom bridge deck is cast and connected to the steel main beam 1, as shown in FIG. Figure 8 shown.

[0080] S4: After the strength maintenance of the prefabricated bottom bridge deck 2 in S3 is completed, the bottom surface and the side surface of the prefabricated bottom bridge deck 2 are fixedly connected to the ribbed steel formwork 4 respectively, so that the prefabricated bottom bridge deck 2 and the steel main beam 1 form a π-shaped structure;

[0081] S5: hoist the π-shaped structure in S4 onto the cap beam, pour concrete into the ribbed steel formwork, the steel skeleton of the bridge deck, and the upper bridge deck 3 in sequence, and then pour the entire bridge deck flat until the overall height of the bridge deck is met, such as Figure 1 and Fig. 9 shown.

[0082] The above description of the embodiments is to facilitate the understanding and use of the invention by those skilled in the art. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative work. Therefore, the present invention is not limited to the above embodiments, and improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the present invention should be within the scope of protection of the present invention.

Claims

1. A composite construction method for enhancing the integrity of a bridge deck, characterized in that: The following steps are involved: S1: welding double-layer shear studs (5) at the connection between the prefabricated bottom bridge deck (2) and the steel main beam (1), and installing ribbed steel formwork (4) at intervals along the longitudinal length of the prefabricated bottom bridge deck (2) and perpendicular to the steel main beam (1); S2: placing a bottom deck steel truss parallel to the ribbed steel formwork (4) on both sides of the ribbed steel formwork (4) in S1, and placing longitudinal steel bars (12) perpendicular to the bottom deck steel truss at equal intervals in the bottom deck steel truss; S3: Welding through steel bars (6) at a preset interval in the longitudinal steel bars (12) in S2 so that the through steel bars (6) penetrate the entire ribbed steel formwork (4), then pouring concrete to obtain the bottom bridge deck (2), achieving the connection between the bottom bridge deck (2) and the steel main beam (1), and performing maintenance; S4: After the strength maintenance of the bottom bridge deck (2) in S3 is completed, the bottom surface and the side surface of the bottom bridge deck (2) are fixedly connected to the ribbed steel formwork (4) respectively, so that the bottom bridge deck (2) and the steel main beam (1) form a π-shaped structure; S5: hoist the π-shaped structure in S4 onto the cap beam, pour concrete into the ribbed steel formwork, the steel skeleton of the bridge deck, and the upper bridge deck (3) in sequence, and then pour the entire bridge deck flatly until the overall height of the bridge deck is met.

2. A composite construction method for enhancing the integrity of a bridge deck according to claim 1, characterized in that: In S1, the ribbed steel formwork (4) is arranged at intervals from the prefabricated bottom bridge deck (2), and the two ends of the bridge are prefabricated bottom bridge decks (2), and the arrangement is n+m+n+m+n+…+n+m+n, Among them, n represents the prefabricated and installed bottom bridge deck; m represents the ribbed steel formwork; + represents the interval.

3. A composite construction method for enhancing the integrity of a bridge deck according to claim 1, characterized in that: In S1, the double-layer shear studs (5) include upper-layer shear studs and lower-layer shear studs, and the upper-layer shear studs and the lower-layer shear studs are arranged correspondingly; The middle and upper parts of the double-layer shear studs (5) are both raised structures, the middle raised structure is located inside the prefabricated bottom bridge deck, and the upper raised structure is located inside the upper bridge deck.

4. A composite construction method for enhancing the integrity of a bridge deck according to claim 1, characterized in that: In S1, the connection between the ribbed steel formwork (4) and the steel main beam (1) is fixedly connected by ribbed steel formwork fixing bolts (8a), and four ribbed steel formwork fixing bolts (8a) are provided. The four ribbed steel formwork fixing bolts (8a) are respectively arranged on the four corners of the contact surface between the ribbed steel formwork (4) and the steel main beam (1).

5. A composite construction method for enhancing the integrity of a bridge deck according to claim 1, characterized in that: In S1, the ribbed steel formwork (4) comprises a steel bottom plate (13), a steel side plate (10) and a perforated transverse rib (9), the perforated transverse rib (9) is welded to the steel bottom plate (13), and the perforated transverse rib (9) and the steel bottom plate (13) are both vertically welded to the steel side plate (10); The thickness of the steel bottom plate (13) and the steel side plate (10) is 3-6 mm, and the thickness of the perforated transverse rib (9) is 9-11 mm; The spacing between the holes on the perforated transverse rib (9) is 290-310 mm, and the diameter of the holes is larger than the diameter of the steel bars (6) passing through.

6. A composite construction method for enhancing the integrity of a bridge deck according to claim 5, characterized in that: The steel side plate (10) is fixedly connected to the side of the prefabricated bottom bridge deck (2) by using steel side form fixing bolts (8b), and the steel bottom plate (13) is fixedly connected to the bottom surface of the prefabricated bottom bridge deck (2) by using steel bottom plate fixing bolts (8c); The steel side plate (10) comprises a steel side plate body and a steel side plate extension, wherein the length of the steel side plate extension is half the length of the prefabricated and installed bottom bridge deck (2); The steel bottom plate (13) comprises a steel bottom plate body and a steel bottom plate extension portion, wherein the length of the steel bottom plate extension portion is 45-55 mm; The steel side plate extension and the steel bottom plate extension are both provided with a plurality of holes, and the spacing between the plurality of holes is 400 mm.

7. A composite construction method for enhancing the integrity of a bridge deck according to claim 1, characterized in that: In S2, the bottom bridge deck steel truss includes a structural steel truss (11) and a connecting steel truss (7), the height of the structural steel truss (11) is less than the height of the prefabricated bottom bridge deck (2), the structural steel truss (11) includes an upper layer of steel bars and a lower layer of steel bars, the lower layer of steel bars is located inside the prefabricated bottom bridge deck (2), and the upper layer of steel bars is reserved on the upper part of the prefabricated bottom bridge deck (2) and cast inside the upper bridge deck (3); The height of the connecting steel bar truss (7) is greater than the height of the prefabricated bottom bridge deck (2).

8. A composite construction method for enhancing the integrity of a bridge deck according to claim 7, characterized in that: In S2, the longitudinal steel bars (12) include a top steel bar and a bottom steel bar, the top steel bar is fixedly connected to the upper steel bar, and the bottom steel bar is fixedly connected to the lower steel bar.

9. A composite construction method for enhancing the integrity of a bridge deck according to claim 1, characterized in that: The through-steel bars (6) include through-steel bars (6) on the side a and through-steel bars (6) on the side b. The through-steel bars (6) on the side a and through-steel bars (6) on the side b are alternately and spacedly passed through the holes of the perforated transverse ribs (9) in the ribbed steel formwork (4), and are arranged on both sides of the ribbed steel formwork (4) in opposite directions.

10. A composite construction method for enhancing the integrity of a bridge deck according to claim 1, characterized in that: In S5, the upper bridge deck (3) is cast as a whole of the entire bridge; The ribbed steel formwork (4) is a permanent formwork for the bridge deck and is not removed after the upper bridge deck (3) is constructed.

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