Wet joint structure of wide prefabricated I-shaped beam bridge

Abstract

The utility model relates to a wet joint structure of a wide prefabricated I-shaped beam bridge, the wide prefabricated I-shaped beam bridge comprises a plurality of parallel I-shaped prefabricated beams, a plurality of bottom templates are erected between the top surfaces of upper flange plates of the adjacent prefabricated beams along the bridge direction, the side edges of the adjacent bottom templates are connected with each other, each bottom template is provided with a steel reinforcement framework, and the steel reinforcement frameworks are connected with the I-shaped prefabricated beams. Wet joint concrete is poured on the bottom formwork and the steel reinforcement framework, and the bottom formwork and the wet joint concrete are poured into a whole. When the bottom formwork is installed, a support does not need to be erected, the construction period can be shortened, cost can be reduced, the bottom formwork serves as a permanent structure of the wet joint, concrete at the bottom of the wet joint can be prevented from cracking, and the bearing capacity of a bridge is improved.

Description

Technical Field

[0001] This utility model belongs to the field of bridge construction technology and relates to a wet joint structure for a wide-span precast I-beam bridge. Background Technology

[0002] Precast beams are classified into box girders, T-beams, and I-beams according to their cross-sectional structural types. When used in wide-span bridge construction, multiple precast beams need to be spliced ​​laterally, with adjacent precast beams connected by cast-in-place wet joints. For box girders and T-beams, due to their wider central and bottom sections, steel reinforcement joints are typically pre-installed on the outer side of their flanges. During wet joint construction, the pre-installed steel reinforcement between the flanges of adjacent precast beams is connected. A bottom formwork is installed at the bottom of the flange reinforcement, which can be fixed on the bridge using a suspended formwork method. Then, concrete is poured between the two precast beams to form a wet joint, with the wet joint concrete flush with the top surface of the precast beam. For I-beams, due to their narrower central web, to ensure the bridge deck's load-bearing capacity and more effectively transfer the bridge deck load to the substructure, the wet joint is typically formed by integrally pouring bridge deck concrete between the upper flanges of adjacent precast beams and on the top surface of the upper flanges of each precast beam. Therefore, during the fabrication of I-beams, steel reinforcement joints are not installed on the outer side of the flanges. Figure 1 As shown, during the construction of the wet joint of Type I beam 1, a steel reinforcement cage 2 is laid on the top surface of the upper flange plate of the precast beam, and a bottom formwork 3' is installed below the upper flange plate of the adjacent precast beam. Then, wet joint concrete 4 is poured. The bottom formwork is generally made of wood and is removed after the wet joint construction is completed.

[0003] This construction method has the following problems:

[0004] 1. The bottom formwork 3 can only be supported by temporary scaffolding 5 erected under the bridge. The scaffolding construction period is long (accounting for about 30% of the total construction period), the investment cost is high, and the construction is difficult in the construction environment where it is not easy to erect scaffolding under the bridge.

[0005] 2. Due to the large thickness of the wet joint concrete 4 between adjacent flange plates (comparable to the thickness of the upper flange plate) and the absence of steel reinforcement, it is necessary to add expansion agents or fiber materials to the concrete. After the concrete is poured, a large amount of curing work is required for the bottom concrete. The process is complicated. Moreover, due to temperature stress and shrinkage deformation, cracking of large-volume cast-in-place concrete is difficult to control. According to statistics, the cracking rate is as high as 40%, which affects the quality of the bridge. Summary of the Invention

[0006] The purpose of this utility model is to address the above-mentioned problems by providing a wet joint structure for a wide-span precast I-beam bridge that is simple to construct, has reliable quality, and is less prone to concrete cracking.

[0007] The technical solution of this utility model is as follows:

[0008] A wet joint structure for a wide-span precast I-beam bridge, comprising multiple parallel I-beams, with the upper flanges of adjacent precast beams connected by wet joints. The structure is characterized by: multiple bottom formwork panels erected along the bridge direction between the top surfaces of the upper flanges of adjacent precast beams; the sides of adjacent bottom formwork panels being interconnected; a reinforcing steel frame on each bottom formwork panel; and wet joint concrete poured onto the bottom formwork panels and the reinforcing steel frame, forming a single unit with the bottom formwork panels.

[0009] This utility model has the following advantages compared with the prior art:

[0010] 1. Improved construction efficiency: The formwork uses specially made profiled steel panels, which are directly supported on the top surface of the upper flange plate of the precast I-beam during installation. There is no need to build temporary supports, which can shorten the construction period and reduce the construction difficulty.

[0011] 2. Cost savings: It saves on material costs and design and installation procedures for temporary support systems, reducing the overall construction cost of ancillary works by 15% to 22%.

[0012] 3. It helps ensure construction quality: The bottom formwork and the wet joint concrete are poured as one piece, serving as a permanent structure for the wet joint and avoiding the problem of cracking in the bottom concrete of the wet joint; moreover, the bottom formwork uses a U-shaped corrugated plate, which can form multiple transverse ribs at the bottom of the wet joint. From the perspective of structural mechanics, this structure can effectively enhance the compressive strength and load-bearing capacity of the wet joint, ensuring the load-bearing capacity of the bridge. According to experimental data, the 28-day compressive strength of the wet joint structure of this utility model is 12.5% ​​higher than that of the traditional structure. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the wet joint structure and construction method of an existing Type I beam bridge;

[0014] Figure 2 This is a schematic diagram of the transverse cross-sectional structure of the wet joint of this utility model;

[0015] Figure 3 This is a schematic diagram of the longitudinal cross-sectional structure of the wet joint of this utility model;

[0016] Figure 4 This is a schematic diagram of the cross-sectional structure of the bottom template of this utility model;

[0017] Figure 5 This is a schematic diagram of the connection structure between adjacent bottom templates. Detailed Implementation

[0018] like Figure 2 , Figure 3As shown, the wide-span precast I-beam bridge includes multiple parallel I-beams 1, with the upper flange plates of adjacent precast beams connected by wet joints; multiple bottom formwork 3 are erected along the bridge direction between the top surfaces of the upper flange plates of adjacent precast beams, with the sides of adjacent bottom formwork connected to each other, and a steel reinforcement cage 2 is set on each bottom formwork. Wet joint concrete 4 is poured on the bottom formwork and the steel reinforcement cage, and the bottom formwork 3 and the wet joint concrete 4 are cast as one piece.

[0019] In a specific implementation of this utility model, the bottom template 3 can be a U-shaped corrugated plate. For example... Figure 4 , Figure 5 As shown, each bottom formwork 3 is provided with multiple U-shaped corrugations. When the bottom formwork is installed on the precast beam, the corrugations of each bottom formwork are set longitudinally along the transverse direction of the precast beam.

[0020] Furthermore, to facilitate the installation of the wet joint reinforcement cage, a reinforcement positioning groove 31 is set on the top surface of each crest of the bottom formwork 3 along the longitudinal direction of the corrugations; the reinforcement cage 2 includes multiple transverse bars and multiple longitudinal bars welded to the transverse bars, with the multiple transverse bars respectively inserted into the reinforcement positioning grooves on the bottom formwork.

[0021] Furthermore, to increase the bonding force between the bottom formwork and the wet joint concrete, one or two strip-shaped protrusions 32 can be set along the longitudinal direction of the corrugations on the trough of each bottom formwork piece.

[0022] In a specific implementation of this utility model, an interlocking connection structure can be used between adjacent bottom templates. For example... Figure 4 , Figure 5 As shown, as a specific locking connection method, each bottom template has a female rib 33 with the groove facing downward on one side along the longitudinal direction, and a male rib 34 with the protruding upward on the other side along the longitudinal direction. The sides of two adjacent bottom templates are connected by interlocking with each other through the female rib and the arch rib.

[0023] In a specific implementation of this utility model, in order to prevent displacement after the bottom formwork is installed, an L-shaped limiting bar 6 can be provided on the top surface of the flange plate of each I-shaped precast beam. One end of the limiting bar 6 is embedded in the concrete of the precast beam. After the formwork is installed in place, the other end of the limiting bar is pressed against the top surface of the end of the bottom formwork 3.

[0024] The construction method of this utility model is as follows:

[0025] After the I-beams of the wide-span bridge are installed, the bottom formwork is erected on the top surface of the flange plates of two adjacent I-beams. The adjacent bottom formworks are connected by interlocking clips, and the limiting reinforcement bars on the precast beams are pressed tightly against the bottom formwork. A wet joint reinforcement cage is installed on the bottom formwork, and spot-welded to the bottom formwork if necessary. Wet joint concrete is then poured to complete the wet joint construction. The bottom formwork is not removed after the wet joint construction is completed; it serves as a permanent structure of the wet joint. This prevents cracking at the bottom of the wet joint concrete and, together with the reinforced concrete of the wet joint, shares the load, thus improving the bridge deck's load-bearing capacity.

Claims

1. A wet joint structure for a wide-span precast I-beam bridge, the wide-span precast I-beam bridge comprising a plurality of parallel I-beams, the upper flange plates of adjacent precast beams being connected by a wet joint, characterized in that: Multiple bottom formwork panels are erected along the bridge direction between the top surfaces of the upper flange plates of adjacent precast beams. The sides of adjacent bottom formwork panels are connected to each other. Each bottom formwork panel is equipped with a steel reinforcement cage. Wet joint concrete is poured on the bottom formwork panels and the steel reinforcement cage. The bottom formwork panels and the wet joint concrete are cast as one unit.

2. The wet joint structure of the wide-width precast I-beam bridge according to claim 1, characterized in that: The bottom formwork is made of U-shaped corrugated plate, and each bottom formwork has multiple U-shaped corrugations. The corrugations of each bottom formwork are arranged longitudinally along the transverse direction of the precast beam.

3. The wet joint structure of the wide-span precast I-beam bridge according to claim 2, characterized in that: Each crest of the bottom template is provided with a steel bar positioning groove along the longitudinal direction of the corrugations; the steel bar skeleton includes multiple transverse bars and multiple longitudinal bars welded to the transverse bars, with the multiple transverse bars respectively inserted into the steel bar positioning grooves on the bottom template.

4. The wet joint structure of the wide-span precast I-beam bridge according to claim 2, characterized in that: Each bottom template has 1-2 strip-shaped protrusions along the longitudinal direction of the corrugations on the trough.

5. The wet joint structure of the wide-width precast I-beam bridge according to claim 2, characterized in that: The adjacent bottom templates are connected by a snap-fit ​​structure. Each bottom template has a female rib with a downward groove on one side and a male rib with an upward protrusion on the other side. The sides of two adjacent bottom templates are connected by the female rib and the arch rib.

6. The wet joint structure of the wide-width precast I-beam bridge according to claim 2, characterized in that: Each I-shaped precast beam has an L-shaped limiting bar on the top surface of its flange plate. One end of the limiting bar is embedded in the concrete of the precast beam, and the other end is pressed against the top surface of the bottom formwork.

Images