Prefabricated small box girder bridge wet joint superposition construction method

Abstract

The application provides a precast small box girder bridge wet joint superposition construction method, which comprises the following steps: manufacturing a precast reinforced concrete superposition plate; installing a plurality of support pieces arranged along the width direction of the precast reinforced concrete superposition plate directly above the precast reinforced concrete superposition plate; hoisting a wet joint support formwork to the position of the wet joint between two precast small box girders, and erecting the two ends of each support piece on the two precast small box girders respectively; and pouring concrete for the cast-in-situ reinforced concrete wet joint. The precast reinforced concrete superposition plate is arranged at the longitudinal wet joint position of the precast small box girder, which serves as one of the components of the wet joint structure and also serves as a permanent formwork for the cast-in-situ reinforced concrete superposition layer, thereby avoiding the manual climbing and dismantling work of the wet joint post-cast concrete bottom formwork, avoiding the long-term occupation of the bridge bottom existing road by the formwork climbing vehicle, reducing the traffic collision and the safety hidden danger of high-altitude operation.

Description

Technical Field

[0001] This invention relates to the field of building construction technology, and more specifically, to a method for wet joint overlapping construction of precast small box girder bridges. Background Technology

[0002] Precast assembled small box girders are economical in cost, convenient to construct, and offer good long-term social and environmental benefits. Their erection has minimal impact on traffic and the environment, and the construction technology is mature. The prefabrication of the girder body in the factory results in good construction quality, durability, and appearance. The bridge's total life-cycle costs and energy consumption are low, aligning with the national strategy of building industrialization. Therefore, precast assembled small box girders are widely used in urban bridges. While wet joints are conventionally used to connect and solidify each small box girder, the traditional cast-in-place concrete process requires a bottom formwork. Considering that the removal of the bottom formwork requires elevated work platforms occupying road space and manual removal, this process may affect traffic flow on existing urban roads below the bridge, posing safety hazards such as elevated work and traffic collisions. Summary of the Invention

[0003] In view of this, the present invention proposes a construction method for overlapping wet joints of precast small box girder bridges, which aims to solve the problems of the inconvenience of construction and the significant safety hazards caused by the need for manual climbing to remove the bottom formwork of existing bridge cast-in-place concrete wet joints, the long-term occupation of the existing road under the bridge by the climbing vehicle.

[0004] This invention proposes a construction method for wet joint overlapping of precast small box girder bridges. The method includes the following steps: fabricating a precast reinforced concrete composite slab; hoisting the fabricated precast reinforced concrete composite slab to the pre-construction location, and installing several support members arranged along the width direction of the precast reinforced concrete composite slab directly above it, and detachably connecting each support member to the precast reinforced concrete composite slab to form a wet joint support template; wherein the height between the precast reinforced concrete composite slab and the support members is adapted to the flange spacing of the precast small box girder; hoisting the wet joint support template to two precast small box girders... The wet joints between the box girders are located, and the two ends of each of the aforementioned support members are respectively erected on the two precast small box girders, forming a simply supported structure with the flanges of the two precast small box girders as supports and the support members as simply supported beams. Furthermore, the bottom of the precast reinforced concrete composite slab is arranged flush with the flange bottom plate of the precast small box girder. The steel reinforcement skeleton of the cast-in-place reinforced concrete wet joint is tied, and the steel reinforcement of the precast small box girder anchored into the wet joint is extended. Concrete is poured into the cast-in-place reinforced concrete wet joint. After the strength of the cast-in-place reinforced concrete wet joint reaches the preset strength, the support members are removed. The bridge deck concrete of the precast small box girder is poured to connect the precast small box girder and the cast-in-place reinforced concrete wet joint to form an integral structure.

[0005] Furthermore, in the above-mentioned method for constructing wet joints of precast small box girder bridges, the fabrication of precast reinforced concrete composite slabs includes: tying the reinforcing bars of the composite slab in the precast yard, and during the process of tying the reinforcing bars, installing precast threaded rods in the precast yard to fix the precast threaded rods to the reinforcing bars; pouring concrete in the precast yard as the slab body concrete of the precast reinforced concrete composite slab, and embedding the precast threaded rods into the precast reinforced concrete composite slab.

[0006] Furthermore, in the above-mentioned construction method for overlapping wet joints of precast small box girder bridges, the length of the precast screw extending beyond the precast reinforced concrete composite slab is greater than the height of the cast-in-place reinforced concrete wet joint, so that after the cast-in-place reinforced concrete wet joint is poured, the top of the precast screw extends above the cast-in-place reinforced concrete wet joint.

[0007] Furthermore, in the above-mentioned wet joint overlapping construction method for precast small box girder bridges, each of the aforementioned support members is provided with at least one precast threaded rod installed on the precast reinforced concrete composite slab, and each of the aforementioned support members is provided with holes corresponding one-to-one with the precast threaded rods.

[0008] Furthermore, in the above-mentioned wet joint superposition construction method for precast small box girder bridges, the step of connecting each support member and the precast reinforced concrete composite slab into an integral structure in a detachable manner specifically involves: passing precast screws through pre-drilled holes in the support members and connecting the precast screws and support members into an integral structure using nuts.

[0009] Furthermore, in the above-mentioned wet joint overlapping construction method for precast small box girder bridges, two support members are set directly above each of the precast reinforced concrete composite slabs, and the two support members are respectively placed at both ends of the precast reinforced concrete composite slab.

[0010] Furthermore, in the above-mentioned wet joint overlapping construction method for precast small box girder bridges, a precast threaded rod is pre-embedded at each of the four corners of each of the precast reinforced concrete composite slabs, and the four precast threaded rods are detachably connected to the two ends of the two support members respectively.

[0011] Furthermore, the above-mentioned wet joint overlapping construction method for precast small box girder bridge further includes, before each of the aforementioned support members is erected on the two precast small box girders, laying steel pads on the precast small box girders so that the steel pads are placed between the support members and the flanges of the precast small box girders.

[0012] Furthermore, in the above-mentioned construction method for overlapping wet joints of precast small box girder bridges, the length of the support member is greater than the width of the wet joint.

[0013] Furthermore, in the above-mentioned construction method for wet joint overlapping of precast small box girder bridges, each of the aforementioned support members is also equipped with a lifting ring.

[0014] The precast small box girder bridge wet joint composite construction method provided by this invention decomposes the structural system of the precast small box girder bridge wet joint into a prefabricated component combination structure system of "precast composite slab + cast-in-place concrete + support components". By setting the precast reinforced concrete composite slab at the longitudinal wet joint position of the precast small box girder, it serves as both a component of the wet joint structure and a permanent formwork for the cast-in-place reinforced concrete composite layer. This eliminates the need for manual climbing and removal of the bottom formwork of the cast-in-place concrete in the later stage of the wet joint, avoids the long-term occupation of the existing road under the bridge by the formwork removal vehicle, reduces traffic collisions and safety hazards of working at height, and realizes the factory-based, standardized, modular, and mechanized production and installation of the precast small box girder wet joint. It solves the problems of the inconvenience and safety hazards of the construction of the bottom formwork removal of the cast-in-place concrete wet joint of the bridge by manual climbing and the long-term occupation of the existing road under the bridge by the formwork removal vehicle. It forms a scientific, efficient, safe and fast prefabricated small box girder bridge wet joint assembly construction method. Attached Figure Description

[0015] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0016] Figure 1 A flowchart illustrating the wet joint overlapping construction method for precast small box girder bridges provided in this embodiment of the invention;

[0017] Figure 2 This is a front view of the wet joint of a precast small box girder bridge provided in an embodiment of the present invention;

[0018] Figure 3 A top view of the wet joint of a precast small box girder bridge provided in an embodiment of the present invention;

[0019] Figure 4 This is a partial enlarged view of the wet joint of a precast small box girder bridge provided in an embodiment of the present invention;

[0020] Figure 5 A flowchart illustrating the process of manufacturing precast reinforced concrete composite slabs, provided for an embodiment of the present invention. Detailed Implementation

[0021] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the disclosure to those skilled in the art. It should be noted that, unless otherwise specified, the embodiments and features described herein can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0022] See Figure 1 This is a flowchart illustrating the wet joint overlapping construction method for precast small box girder bridges provided in this embodiment of the invention. As shown in the figure, the construction method includes the following steps:

[0023] Step S1: Fabricate precast reinforced concrete composite slabs.

[0024] Specifically, precast reinforced concrete composite slabs 1 can be fabricated in a precast yard. For example, Figures 2 to 4 As shown, there can be multiple precast reinforced concrete composite slabs 1, the specific number of which can be based on the length of the precast small box girder 2 (e.g., Figure 3 The length of the precast reinforced concrete composite slab 1 is determined by the vertical direction shown. Multiple precast reinforced concrete composite slabs 1 can be spliced ​​together to form one of the combined parts of the wet joint structure between precast small box girders 2. In this embodiment, there can be multiple precast small box girders 2, each arranged along the longitudinal direction of the bridge, and multiple precast small box girders 2 arranged parallel to each other on the transverse bridge, forming a longitudinal wet joint between adjacent precast small box girders 2. Each precast reinforced concrete composite slab 1 is pre-embedded with a precast threaded rod 11. To improve the stability of the precast reinforced concrete composite slab 1 support, preferably, a precast threaded rod 11 is pre-embedded at each of the four corners of each precast reinforced concrete composite slab 1, so as to achieve the connection and fixation between the precast reinforced concrete composite slab 1 and the support member 3 through the precast threaded rod 11; the distance between the precast threaded rod 11 and the edge of the precast reinforced concrete composite slab 1 is 10~20cm. In this embodiment, the length of the precast screw 11 extending beyond the precast reinforced concrete composite slab 1 is greater than the height of the cast-in-place reinforced concrete wet joint 5, so that after the cast-in-place reinforced concrete wet joint 5 is poured, the top of the precast screw 11 extends above the cast-in-place reinforced concrete wet joint 5, ensuring that the precast screw 11 can be installed and fixed on the support member 3, and the force of the screw and the composite slab meets the requirements for the hoisting of the composite slab and subsequent cast-in-place concrete construction.

[0025] Step S2: The precast reinforced concrete composite slab is hoisted to the pre-construction location, and several support members arranged along the width direction of the precast reinforced concrete composite slab are installed directly above the precast reinforced concrete composite slab. Each support member is detachably connected to the precast reinforced concrete composite slab to form a whole structure, forming a wet joint support template. The height between the precast reinforced concrete composite slab and the support members is adapted to the flange spacing of the precast small box girder.

[0026] Specifically, firstly, the precast reinforced concrete composite slab 1 is hoisted to the pre-construction location. Then, several supports are installed directly above the precast reinforced concrete composite slab, along the width direction of the precast reinforced concrete composite slab (e.g., ...). Figure 2 The support members 3 are arranged in a horizontal direction (as shown in the figure). Among them, there are two support members 3 directly above each precast reinforced concrete composite slab 1, and the two support members 3 are respectively placed at both ends of the precast reinforced concrete composite slab 1 (e.g., ...). Figure 2 (As shown at the upper and lower ends), to ensure the stability of the support for the precast reinforced concrete composite slab 1. Then, each support member 3 is detachably connected to the precast reinforced concrete composite slab 1 to form an integral structure, forming a wet joint support template. In this embodiment, each support member 3 is provided with at least one precast screw 11 installed on the precast reinforced concrete composite slab 1, and each support member 3 is provided with a hole corresponding to the precast screw 11. The precast screw 11 can be passed through the reserved hole on the support member 3, and the precast screw 11 and the support member 3 can be connected to the support member 3 to form an integral structure through the nut 12. That is, the precast screw 11 located at the four corners of the precast reinforced concrete composite slab 1 can be passed through the reserved hole on the support member 3 and connected and fixed to the support member 3 by the fastening action of the nut 12. Of course, a nut washer can also be provided at the nut 12. In this embodiment, the support member 3 can be an angle steel structure or other structures, and there is no limitation on it in this embodiment. Each support member 3 may also be equipped with a lifting ring 31 for hoisting; the length of the support member 3 is greater than the width of the wet joint to ensure that both ends of the support member 3 can be erected on the two precast small box beams 2 on both sides.

[0027] Step S3: The wet joint support template is hoisted to the wet joint position between the two precast small box girders, and the two ends of each support are respectively erected on the two precast small box girders to form a simply supported structure with the flanges of the two precast small box girders as supports and the support as simply supported beams. Furthermore, the bottom of the precast reinforced concrete composite slab is flush with the flange bottom plate of the precast small box girder.

[0028] Specifically, firstly, the lifting hook of the hoisting equipment passes through the lifting ring 31, smoothly lifting the support member 3, along with the precast bolt 11 and the precast reinforced concrete composite slab 1 fixed thereto, and transporting them to the wet joint position between the two precast small box girders 2. Then, steel pads 4 can be laid on the precast small box girders 2, so that the steel pads 4 are placed between the support member 3 and the flanges of the precast small box girders 2. That is, after placing the steel pads 4 between the support member 3 and the flanges of the precast small box girders 2, the support member 3 is smoothly erected between the two precast small box girders 2, forming a simply supported structure with the flanges of the two precast small box girders 2 as supports and the support member 3 as a simply supported beam. The bottom of the precast reinforced concrete composite slab 1 is flush with the bottom plate of the flange of the precast small box girders 2. The steel pads 4 increase the stress area, reduce pressure, lower the strength requirements of the precast small box girders' concrete flanges, and protect the appearance quality of the finished product.

[0029] Step S4: Tie the reinforcing steel cage of the cast-in-place reinforced concrete wet joint, extend the reinforcing steel of the precast small box girder anchored into the wet joint, and pour concrete into the cast-in-place reinforced concrete wet joint.

[0030] Specifically, firstly, the steel reinforcement skeleton of the cast-in-place reinforced concrete wet joint 5 is tied between the precast reinforced concrete composite slab 1 and the support 3, and the steel reinforcement of the precast small box girder 2 anchored into the wet joint is extended.

[0031] In other words, the upper layer of the precast reinforced concrete composite slab 1 is a cast-in-place reinforced concrete wet joint 5. The reinforcing bars of the precast small box girders 2 on both sides are anchored into the cast-in-place reinforced concrete wet joint 5, and their anchorage length meets the stress requirements. The wet joint of the precast small box girder is formed by the combination of the cast-in-place reinforced concrete wet joint 5 and the precast reinforced concrete composite slab 1. Then, the concrete pouring of the cast-in-place reinforced concrete wet joint 5 is completed, that is, concrete is poured between the precast reinforced concrete composite slab 1 and the support member 3, forming the cast-in-place reinforced concrete wet joint 5 between the precast reinforced concrete composite slab 1 and the support member 3. During pouring, it is fully vibrated and watered for curing until the strength reaches 100%.

[0032] Step S5: After the cast-in-place reinforced concrete wet joint reaches the preset strength, remove the support components. Specifically, after the support component 3, nut 12, and nut washer are removed, they can be used as reusable materials for the construction of the next section of the precast small box girder bridge wet joint.

[0033] Step S6 involves pouring precast small box girder bridge deck concrete to connect the precast small box girder with the cast-in-place reinforced concrete wet joint to form an integral structure. Specifically, once the entire span of precast small box girder and wet joint construction is completed, it is as follows: Figure 2The construction of multiple cast-in-place reinforced concrete wet joints 5 is completed. Precast small box girder bridge deck concrete is poured, covering the precast bolts 11. The entire span of the precast small box girder 2 is then connected to the cast-in-place reinforced concrete wet joints 5 to form a unified structure. The concrete is thoroughly vibrated and cured with water. The formwork system, composed of the precast reinforced concrete composite slab 1, precast bolts 11, nuts 12, nut steel washers, and support members 4, can meet the cast-in-place concrete construction load requirements of the cast-in-place reinforced concrete wet joints 5.

[0034] See Figure 5 This is a flowchart illustrating the process of manufacturing a precast reinforced concrete composite slab according to an embodiment of the present invention. As shown in the figure, the manufacturing of the precast reinforced concrete composite slab includes the following sub-steps:

[0035] Sub-step S11 involves tying the reinforcing bars of the composite slab in the prefabrication yard, and during the tying process, installing prefabricated threaded rods in the prefabrication yard to fix the prefabricated threaded rods to the reinforcing bars. Specifically, ordinary reinforcing bars of the prefabricated reinforced concrete composite slab 1 are tied in the prefabrication yard, and prefabricated threaded rods 11 are vertically embedded during the fabrication process. The prefabricated threaded rods 11 are then welded to the reinforcing bar skeleton of the prefabricated reinforced concrete composite slab 1 to ensure a reliable connection. The length of the prefabricated threaded rods 11 protruding from the prefabricated reinforced concrete composite slab 1 should not be less than the height of the wet joint 5 of the prefabricated small box girder bridge. The stress of the connection between the threaded rods and the composite slab meets the requirements for the hoisting of the composite slab and subsequent cast-in-place concrete construction.

[0036] In sub-step S12, concrete is poured in the precast slab yard as the slab body concrete for the precast reinforced concrete composite slab, and precast bolts are embedded in the precast reinforced concrete composite slab. Specifically, the slab body concrete of the precast reinforced concrete composite slab 1 is poured, ensuring sufficient storage time to reduce the shrinkage and creep effect of the concrete, and water curing is carried out during this period until 100% strength is achieved.

[0037] In summary, the precast small box girder bridge wet joint composite construction method provided in this embodiment decomposes the structural system of the precast small box girder bridge wet joint into a prefabricated component combination structural system of "precast composite slab + cast-in-place concrete + support components". By setting the precast reinforced concrete composite slab 1 at the longitudinal wet joint position of the precast small box girder 2, it serves as both a component of the wet joint structure and a permanent formwork for the cast-in-place reinforced concrete composite layer. This eliminates the need for manual climbing and removal of the bottom formwork of the cast-in-place concrete in the later stage of the wet joint, avoids the long-term occupation of the existing road under the bridge by the formwork removal vehicle, reduces traffic collisions and safety hazards of working at height, and realizes the factory-based, standardized, modular, and mechanized production and installation of the precast small box girder wet joint. It solves the problems of the inconvenience and safety hazards of the construction of the bottom formwork removal of the cast-in-place concrete wet joint of the bridge, which requires manual climbing and the long-term occupation of the existing road under the bridge by the formwork removal vehicle. It reduces the amount of manual work, improves construction efficiency, and forms a scientific, efficient, safe and fast prefabricated small box girder bridge wet joint assembly construction method.

[0038] It should be noted that in the description of this invention, the terms "upper", "lower", "left", "right", "inner", "outer", etc., which indicate directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings. This is only for the convenience of description and is not intended to indicate or imply that the device or element must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of this invention.

[0039] Furthermore, it should be noted that, in the description of this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0040] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A method for overlapping wet joints in a precast small box girder bridge, characterized in that, Includes the following steps: Fabrication of precast reinforced concrete composite slabs; The precast reinforced concrete composite slab is hoisted to the pre-construction location, and several support members arranged along the width direction of the precast reinforced concrete composite slab are installed directly above it. Each support member is detachably connected to the precast reinforced concrete composite slab to form a whole structure, forming a wet joint support template. The height between the precast reinforced concrete composite slab and the support members is adapted to the flange spacing of the precast small box girder. The wet joint support template is hoisted to the wet joint position between the two precast small box girders, and the two ends of each of the support members are respectively erected on the two precast small box girders to form a simply supported structure with the flanges of the two precast small box girders as supports and the support members as simply supported beams. Furthermore, the bottom of the precast reinforced concrete composite slab is arranged flush with the flange bottom plate of the precast small box girder. The steel reinforcement cage of the cast-in-place reinforced concrete wet joint is tied, and the steel reinforcement of the precast small box girder is extended and anchored into the wet joint. The concrete is then poured into the cast-in-place reinforced concrete wet joint. After the wet joint of the cast-in-place reinforced concrete reaches the preset strength, the supporting components are removed. The precast small box girder bridge deck concrete is poured to connect the precast small box girder with the cast-in-place reinforced concrete wet joint to form an integral structure. The fabrication of precast reinforced concrete composite slabs includes: The reinforcing bars of the composite slab are tied in the prefabrication yard, and during the binding process, prefabricated bolts are installed in the prefabrication yard to fix the prefabricated bolts to the reinforcing bars. Concrete is poured in the precast yard of the composite slab to serve as the slab body concrete for the precast reinforced concrete composite slab, and the precast bolts are embedded in the precast reinforced concrete composite slab. The length of the precast screw extending beyond the precast reinforced concrete composite slab is greater than the height of the cast-in-place reinforced concrete wet joint, so that after the cast-in-place reinforced concrete wet joint is poured, the top of the precast screw extends above the cast-in-place reinforced concrete wet joint. Each of the aforementioned support members is provided with at least one precast screw installed on the precast reinforced concrete composite slab, and each of the aforementioned support members is provided with a hole corresponding to the precast screw. The method of detachably connecting each support member to the precast reinforced concrete composite slab to form an integral structure is as follows: The prefabricated screw is passed through the pre-drilled hole on the support and connected to the support as a whole structure by the nut; Two support members are provided directly above each of the precast reinforced concrete composite slabs, and the two support members are respectively placed at both ends of the precast reinforced concrete composite slab. Each of the four corners of the precast reinforced concrete composite slab is pre-embedded with a precast threaded rod, and the four precast threaded rods are detachably connected to the two ends of the two support members respectively. The length of the support member is greater than the width of the wet joint.

2. The method for overlapping wet joints of precast small box girder bridges according to claim 1, characterized in that, Before each of the aforementioned support members is erected on one of the two precast small box girders at both ends, the process further includes: A steel pad is laid on the precast small box girder so that the steel pad is placed between the support and the flange of the precast small box girder.

3. The method for overlapping wet joints of precast small box girder bridges according to claim 1, characterized in that, Each of the aforementioned support members is also equipped with a lifting ring.

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