Construction method for improving arch smoothness of large-span curve steel structure arch rib

Abstract

The invention discloses a construction method for improving the arch smoothness of an arch rib of a large-span curve steel structure. After a platform bridge box-shaped steel beam is installed, a 50T truck-mounted crane is inspected comprehensively, a temporary supporting rack is hoisted and spliced according to symmetry requirements, and size and angle errors are strictly controlled. Installing a stable pull rod, cleaning a welding part, and ensuring the stability of the rack. The 100T truck-mounted crane and the crank arm truck assist in mounting arch ribs, and are temporarily welded and fixed in a multi-point and multi-direction mode. Then mounting arch rib secondary rods, and mounting and tensioning suspenders from the middle part of the overbridge to the two ends of the overbridge. Finally, the temporary supporting rack is dismantled, and an accessory structure is installed. According to the method, the problems of supporting, positioning and stability of large-span curve steel structure arch rib construction are solved, the construction quality and arch smoothness are improved, and the method has remarkable technical advantages and practical value.

Description

Technical Field

[0001] The invention relates to the technical field of traffic civil engineering, in particular to a construction method for improving the arch smoothness of a large-span curved steel structure arch rib. Background Art

[0002] After the prefabricated hoisted pedestrian bridge deck box steel beam is installed, the bridge deck arch ribs are assembled. The arch ribs are generally set along the outer edge of the bridge at the upper part of the bridge deck and connected to the bridge deck structure with hangers. The arch ribs are welded on site and require high installation accuracy. The schematic diagram of the pedestrian bridge arch ribs is as follows: Figure 1 .

[0003] Since the arch ribs of the pedestrian bridge are not only large in span but also heavy in weight, the steel structure arch ribs need to be constructed in sections. In order to ensure sufficient support conditions during the hoisting and welding of the large-span curved arch ribs, a temporary support platform is set up on the bridge deck before the arch ribs of the pedestrian bridge are assembled to provide support conditions for the installation of the arch ribs. Figure 2 , Figure 3 The supporting columns of the arch ribs are spliced ​​on the bridge deck with H-shaped steel to form a rectangular support frame with a length of 1.5m and a width of 1m. The height of each layer is 1.5m, with a support beam in the middle, a cantilever length of 1.5m at the top, and an oblique support beam at the bottom. There are two types of support frames: 5.355m and 8.055m. The bottom of the gantry is welded to the bridge deck. The bottom on-site welding is shown in the figure below. Figure 4 The platform is stabilized by the tie rods, which are bidirectionally inclined and connected with each other. Figure 5 After the arch rib is installed, it is temporarily welded to the temporary support frame with steel bars at multiple points and in multiple directions to ensure a firm connection with the frame. The temporary welding fixation diagram is as follows Figure 6 .

[0004] In the field of transportation civil engineering, the construction of large-span curved steel arch ribs for pedestrian overpasses has always been a very challenging task. In the past construction technology, the construction of large-span curved steel arch ribs faced many difficulties that were difficult to overcome.

[0005] Due to the large span and heavy weight of the arch ribs of the large-span curved steel structure, the conventional segmented lengthening welding process lacks an effective support system during implementation. The traditional support structure cannot provide stable and sufficient support conditions for the arch rib hoisting and welding construction, resulting in the arch ribs being prone to shaking, displacement, and even deformation during construction, which seriously affects the forming quality of the arch ribs.

[0006] The defects of connection technology are also very obvious. The existing connection method is poor in stability, which makes the arch ribs unstable during installation, making it difficult to ensure the precise connection between components and the stability of the overall structure, greatly increasing the construction risk and making it easy for the structure to become unstable.

[0007] In addition, in the installation and positioning of segmented arch ribs, existing technical means cannot achieve high-precision positioning. Due to the lack of effective positioning reference and accurate positioning method, it is difficult for each segmented arch rib to form a smooth arch curve after installation, which not only affects the appearance of the pedestrian bridge, but also has an adverse effect on the uniformity and stability of its structural force, reducing the overall quality and service life of the bridge.

[0008] Based on the in-depth analysis of the pain points of these prior arts, the present invention proposes a new construction method for improving the smoothness of the arch ribs of large-span curved steel structures, aiming to fundamentally solve the above-mentioned problems and improve construction quality and efficiency. Summary of the invention

[0009] The purpose of the present invention is to provide a construction method for improving the smoothness of the arch ribs of large-span curved steel structures, so as to overcome the technical bottlenecks existing in the existing large-span curved steel structure arch rib construction, and through innovative construction methods, comprehensively solve the problems of weak support system, poor connection stability and low installation positioning accuracy, thereby significantly improving the construction quality of large-span curved steel structure arch ribs, ensuring that the arch smoothness reaches a high standard, and providing solid protection for the safety and beauty of pedestrian overpasses.

[0010] In order to achieve the above object, the present invention is implemented through the following technical scheme: a construction method for improving the arch smoothness of the arch rib of a large-span curved steel structure, comprising the following steps:

[0011] Step S1, temporary support platform hoisting: After the box-shaped steel beam of the overpass is installed, a 50T truck crane with stable performance is used to accurately hoist two specific specifications (5.355m and 8.055m) of temporary support platforms to the bridge deck in strict accordance with the design symmetry requirements. The support columns of the support platform are spliced ​​on the bridge deck into a 1.5m long and 1m wide rectangular structure using H-shaped steel. The height of each floor is set to 1.5m. A support beam is set in the middle to enhance the structural strength. The top is cantilevered 1.5m, and an inclined support beam is added below to build a stable support structure.

[0012] Step S2, temporary support frame fixation: After the installation, the frame is reinforced by a carefully designed stability tie rod, using a two-way inclined tie rod and a mutual tie rod to ensure that the frame has good stability in all directions. At the same time, considering that the weight of a single frame is about 1-2 tons, the bottom of the frame is directly welded to the 30mm thick bridge deck to further enhance its stability and lay a solid foundation for subsequent construction.

[0013] Step S3, arch rib installation and temporary fixation: After the temporary support stand is built, a 100T truck crane is used to hoist the arch rib, and a boom truck is used for precise auxiliary installation. The arch ribs on each side are finely divided into 4 sections for hoisting. After hoisting in place, steel bars are used for multi-point and multi-directional temporary welding to make the arch ribs and the stand tightly and firmly connected, effectively avoiding the shaking and displacement of the arch ribs during the installation process, and creating stable conditions for the subsequent welding process.

[0014] Step S4, arch rib secondary rod installation: After the arch rib installation is completed and strictly checked and confirmed to be correct, a 50-ton truck crane is used to flexibly determine the installation sequence based on the actual working conditions and construction requirements on site, and efficiently complete the lifting and installation of the arch rib secondary rod.

[0015] Step S5, installation of overpass suspenders: After the arch rib secondary rods are installed, the overpass suspenders are installed and tensioned in an orderly manner from the middle of the overpass to both ends. During the whole process, the tensioning force and installation position accuracy of the suspenders are precisely controlled in strict accordance with high-precision construction standards to ensure that the overpass structure is evenly stressed and stable.

[0016] Step S6, dismantling the temporary support scaffold: After the installation of the suspender is completed and all indicators meet the design requirements, the temporary support scaffold of the bridge face is carefully dismantled. During the dismantling process, comprehensive protective measures are taken to avoid any damage to the completed structure and components of the overpass, and then the installation of the auxiliary structure of the overpass is successfully completed.

[0017] The present invention has the following beneficial effects:

[0018] The present invention successfully provides reliable and sufficient support conditions for the segmented lifting and extension welding of the arch ribs of large-span curved steel structures by introducing a temporary support platform with an innovative design, which completely changes the previous situation of weak support system and greatly improves the quality and stability of arch rib construction.

[0019] The unique setting of stability tie rods, welding of the bottom of the scaffolding and the bridge deck, and multi-point and multi-directional temporary welding of steel bars effectively solved the stability problem during the installation of the arch ribs, significantly reduced construction risks, and ensured the safety and controllability of the construction process.

[0020] The temporary support scaffold not only serves as the preliminary positioning reference for the installation of the arch ribs, but also achieves precise positioning of the arch ribs through multi-directional welding with the steel bars on the top of the scaffold, greatly improving the positioning accuracy of each segmented arch rib, effectively ensuring the smoothness of the arch shape of the large-span curved steel structure arch ribs, and improving the overall aesthetics and structural performance of the pedestrian bridge. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Other features, objects and advantages of the present invention will become more apparent from the detailed description of non-limiting embodiments made with reference to the following drawings:

[0022] Figure 1 This is a schematic diagram of the arch rib of the pedestrian bridge;

[0023] Figure 2 This is one of the schematic diagrams of the temporary support stand;

[0024] Figure 3 This is the second schematic diagram of the temporary support stand;

[0025] Figure 4 This is a schematic diagram of on-site welding between the bottom of the temporary support scaffold and the bottom of the bridge deck;

[0026] Figure 5 To temporarily support the scaffold, a pull rod is used to achieve stability, with bidirectional diagonal pull and a mutual pull connection diagram;

[0027] Figure 6 This is a schematic diagram of temporary welding and fixing of the arch rib to the temporary support frame after installation;

[0028] Figure 7 This is a schematic diagram of the hoisting and erection of the temporary support scaffold;

[0029] Figure 8 This is one of the schematic diagrams for the installation and temporary fixation of the arch rib;

[0030] Fig. 9 This is the second schematic diagram of the installation and temporary fixation of the arch rib;

[0031] Fig.10 This is the schematic diagram of the arch rib secondary rod installation;

[0032] Fig.11 Schematic diagram of the installation of the overpass hanger and the dismantling of the temporary support platform. DETAILED DESCRIPTION

[0033] The present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments. The exemplary embodiments and descriptions of the present invention are used to explain the present invention, but are not intended to limit the present invention.

[0034] It should be noted that all directional indications in the embodiments of the present invention (such as up, down, left, right, front, back, upper end, lower end, top, bottom...) are only used to explain the relative position relationship, movement status, etc. between the components in a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0035] In the present invention, unless otherwise clearly defined and limited, the term "connection" should be understood in a broad sense, for example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0036] In addition, in the present invention, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features; in addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in the field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0037] The present invention is further described in detail below in conjunction with the accompanying drawings.

[0038] Reference Figure 4-Figure 11 A construction method for improving the smoothness of the arch rib of a large-span curved steel structure: mainly composed of temporary support gantry hoisting, temporary support gantry fixing, arch rib temporary installation and fixing, arch rib installation and other construction methods. Temporary support gantry hoisting is to install two types of temporary support gantry 2 and 3 on the bridge deck according to symmetrical requirements. Temporary support gantry fixing is to weld the installed gantry directly to the bridge deck through a stability tie rod (bidirectional inclined and one more mutual pulling connection). Temporary arch rib installation and fixing is to use steel bars for multi-point and multi-directional temporary welding. The arch rib is installed symmetrically from both ends to the middle of the span. After the arch rib and the secondary rod are installed, the arch rib hanger is installed. Finally, the temporary support gantry on the bridge deck is removed.

[0039] The following is a detailed introduction to the construction method for improving the smoothness of the arch ribs of large-span curved steel structures. The specific steps are:

[0040] (a) Temporary support frame hoisting. After the box-shaped steel beams of the overpass are installed, a 50T truck crane is used to hoist and set up a temporary support frame for the arch ribs. Figure 7 .

[0041] (b) Temporary support frame fixation. The stability tie rod adopts bidirectional inclined pull and adds a mutual pull connection. The weight of a single tire frame is about 1-2 tons, so the bottom of the tire frame can be directly welded on the bridge deck (bridge deck thickness 30mm) on site. Figure 4 , Figure 5 .

[0042] (c) Arch rib installation and temporary fixation. After the temporary support frame is installed, use a 100T truck crane to hoist the arch ribs and a boom truck to assist in the installation of the arch ribs. The arch ribs on each side are hoisted in 4 sections. Figure 8 , Fig. 9 The temporary installation and fixing method uses multi-point and multi-directional temporary welding of steel bars to ensure a firm connection with the tire frame. Figure 6 .

[0043] (d) Installation of arch rib secondary rods. After the arch ribs are installed, use a 50-ton truck crane to hoist and install the arch rib secondary rods. The installation sequence depends on the actual situation. Fig.10

[0044] (e) Installation of overpass suspenders. After the arch rib secondary rods are installed, the overpass suspenders are installed and tensioned from the middle to both ends. Fig.11 .

[0045] (f) Remove the temporary support frame. After the installation of the suspender is completed, start to remove the temporary support frame of the bridge face and install the auxiliary structure of the overpass. Fig.11 .

[0046] Specifically, in a construction method for improving the arch smoothness of a long-span curved steel structure arch rib of the present invention, it should be noted that:

[0047] Temporary support stand hoisting:

[0048] After the installation of the overpass box steel beam was completed, professional technicians were arranged to conduct a comprehensive performance test and safety inspection on the 50T truck crane, including but not limited to the crane's lifting capacity, braking system, hydraulic system and the connection stability of each component, to ensure that all performance indicators of the crane met the construction requirements.

[0049] According to the symmetry requirements determined by the design drawings, the installation position of the temporary support gantry was accurately marked on the bridge deck in advance. During the lifting process, experienced crane drivers operated and cooperated with professional commanders to communicate in real time through communication equipment such as walkie-talkies to ensure a smooth and accurate lifting process.

[0050] When splicing the support frame, strictly control the splicing error of the H-shaped steel, use high-precision measuring tools, such as total stations, to measure the length, width and height of each layer of the support frame, to ensure that the dimensional error of the rectangular structure with a length of 1.5m and a width of 1m is controlled within the allowable range, and the error of each layer height of 1.5m does not exceed the specified value. At the same time, ensure that the installation angle and position of the support beam and the oblique support beam are accurate to build a stable support structure. Figure 7 shown.

[0051] Temporary support stand fixation:

[0052] Before installing the stability tie rod, check the material and specifications of the tie rod to ensure that it meets the design requirements. During installation, follow the method of bidirectional diagonal pulling and adding a mutual pulling connection, accurately adjust the angle and tension of the tie rod, and use professional tension testing equipment to ensure that the tension of each tie rod is uniform and reaches the design value, ensuring the stability of the stand in all directions. Figure 4 , Figure 5 shown.

[0053] Before welding the bottom of the gantry to the bridge deck, the welding part is thoroughly cleaned to remove surface impurities such as oil, rust, etc., and appropriate welding processes and welding materials are used, such as welding rods that match the bridge deck material, and welders holding corresponding qualification certificates perform welding operations. During the welding process, the welding current, voltage and welding speed are strictly controlled to ensure welding quality. After welding is completed, appearance inspection and non-destructive testing, such as ultrasonic flaw detection, are carried out to ensure that there are no defects such as cracks and pores in the welding part.

[0054] Arch rib installation and temporary fixation:

[0055] Before the 100T truck crane and articulated boom truck were put into place, the work site was leveled and compacted to ensure that the crane and articulated boom truck remained stable during operation. A comprehensive performance and safety inspection was also carried out on the 100T truck crane and articulated boom truck, including the crane's lifting height, lifting radius, and the articulated boom truck's reach and stability.

[0056] When lifting the arch rib, reasonably set the lifting points on the arch rib, use special lifting equipment and rigging, such as high-strength wire rope and shackles, to ensure that the lifting points are evenly distributed to avoid deformation of the arch rib during lifting. During the lifting process, maintain a slow and steady speed to prevent the arch rib from shaking.

[0057] When the arch rib is hoisted to the top of the temporary support frame, it is slowly lowered under the command of professional technicians. When using steel bars for multi-point and multi-directional temporary welding, the material and specifications of the steel bars should be inspected in advance to ensure that they meet the welding strength requirements. Welding personnel operate according to the pre-established welding process, control the welding sequence and welding parameters, ensure that each welding point is firm and reliable, and conduct an appearance inspection after welding to ensure the welding quality. Figure 6 shown.

[0058] Arch rib secondary rod installation:

[0059] After the arch ribs are installed, professional quality inspectors are organized to conduct a comprehensive inspection of the installation quality of the arch ribs, including the position, elevation, verticality, etc. of the arch ribs, to ensure that all indicators meet the design and specification requirements.

[0060] According to the actual working conditions on site, such as the spatial layout of the construction site, the parking position of the equipment and the stacking position of the arch rib secondary rods, and in combination with the construction progress requirements, a reasonable arch rib secondary rod installation sequence is formulated. When using a 50-ton truck crane for lifting, the crane is also inspected for performance and safety to ensure a safe and efficient lifting process. Fig.10 shown.

[0061] Overpass suspension rod installation:

[0062] After the arch rib secondary rod is installed, a detailed plan for the installation and tensioning of the overpass suspenders is formulated according to the design requirements and construction specifications. The plan clearly stipulates the tensioning force value, tensioning sequence, and position accuracy requirements of the suspenders.

[0063] During the installation and tensioning process, high-precision tensioning equipment, such as intelligent tensioning jacks, etc., are used, and professional surveying personnel are equipped with total stations and other measuring tools to monitor the tensioning force and installation position of the hangers in real time. The installation and tensioning are carried out in the order from the middle of the overpass to both ends to ensure that the tensioning force of each hanger is uniform and the overpass structure is balanced. Fig.11 shown.

[0064] Dismantle the temporary support stand:

[0065] After the installation of the boom is completed and all indicators have been tested to meet the design requirements, a detailed temporary support stand removal plan is formulated, which specifies the removal sequence, removal methods, and safety protection measures.

[0066] During the demolition process, professional demolition equipment, such as small cranes or manual hoists, are used to carry out demolition in the order of top to bottom, first the auxiliary components and then the main structure. Obvious warning signs are set up in the demolition area, and special personnel are arranged to monitor the site to prevent unauthorized personnel from entering the demolition area. At the same time, effective protective measures are taken, such as laying protective mats on the surface of the overpass structure, to avoid damage to the completed structure and components of the overpass during the demolition process. After the demolition is completed, the site is cleaned up in a timely manner, and then the installation of the auxiliary structure of the overpass is successfully completed in accordance with the design requirements and construction specifications. Fig.11 shown.

[0067] 3. Beneficial Effects

[0068] (1) Before installing the large-span curved steel structure arch rib, it is innovatively proposed to use a temporary support rig for the construction of the large-span steel structure arch rib. The use of the temporary support rig can provide sufficient support conditions for the arch rib segmented hoisting, extension and welding construction. The use of the temporary support rig changes the problem of insufficient bearing capacity of the existing technology and improves the construction quality of the arch rib.

[0069] (2) After the temporary support scaffold is installed, the bottom of the scaffold is directly welded to the bridge deck through stability tie rods (bidirectional inclined tie rods with an additional mutual tie rod). The temporary installation and fixation of the arch ribs is done by multi-point and multi-directional temporary welding of steel bars. This solves the problem of insufficient stability during arch rib installation caused by the instability of existing connection technology. Tie rods, bottom welding and steel bar welding solve the problem of arch rib instability caused by hidden rotation.

[0070] (3) The use of a temporary support stand can provide a basis for locating the installation position of the arch rib. The stand can be used as a preliminary positioning for the arch rib installation, and then the arch rib and the steel bar on the top of the stand are precisely positioned through multi-directional welding, ensuring the positioning accuracy of each segmented arch rib. This solves the problem of inaccurate installation positioning of segmented arch ribs in the existing technology and improves the smoothness of the arch rib arch of the large-span curved steel structure.

[0071] Implementation Cases:

[0072] During the construction of a flyover project in a certain city, each link was closely linked and achieved remarkable results. During the temporary support platform hoisting stage, the 50T truck crane was fully inspected one week in advance, and the loose bolts of the brake system were tightened in time. On the day of hoisting, with the help of efficient command by walkie-talkie, the hoisting operation was completed 2 hours ahead of schedule. The dimensional error and angle error were accurately controlled during splicing, and the platform was built firmly.

[0073] In another overpass project in a certain city, the temporary support frame fixing process was strictly controlled. After the material inspection found that the tensile strength of some tie rods was insufficient, they were immediately replaced. During installation, professional equipment was used to accurately control the tension within ±5% of the design value. Matching welding rods were used for the bottom of the welding frame. After flaw detection, the defect rate was only 0.5%.

[0074] During the construction of a pedestrian overpass in a key city, the arch rib installation and temporary fixing work was meticulous. Before the 100T truck crane and the articulated arm truck were put in place, the work site was leveled and compacted for 3 days. When lifting the arch rib, software simulation was used to determine the best lifting point, and suitable lifting equipment was selected to control the deformation of the arch rib within 10mm. The sampling pass rate of temporary welded steel bars reached 100%.

[0075] During the construction of a scenic area overpass project, the installation of the arch rib secondary rods focused on quality and actual conditions. The total station was used to measure the arch rib verticality deviation beyond the allowable range and timely adjustments were made. Considering the large number of tourists and narrow site in the scenic area, the installation sequence was reasonably arranged. A comprehensive inspection was carried out before the 50-ton truck crane was used for lifting, and the lifting was completed one day ahead of schedule.

[0076] During the installation of the overpass suspenders in a main road overpass project in a certain city, the plan was scientifically formulated and experts were invited to demonstrate the plan. During the installation and tensioning process, the tensioning force error was controlled within ±3% using an intelligent tensioning jack, and the position accuracy error was controlled within 5mm through real-time monitoring by a total station, ensuring that the overpass structure was evenly stressed.

[0077] When removing the temporary support scaffolding for a commercial center overpass project, the project was well prepared and dismantled in an orderly manner. A detailed plan was prepared and explained in advance, and a small crane was used in conjunction with a manual hoist to dismantle the structure in order. A 5cm thick protective mat was laid to avoid damaging the overpass structure, and the site was cleaned up in a timely manner after the dismantling.

[0078] In summary, the present invention aims to solve the problems of weak support system, poor connection stability and low installation positioning accuracy in the construction of large-span curved steel structure arch ribs, so as to improve the construction quality and arch smoothness and ensure the safety and beauty of the pedestrian overpass.

[0079] The technical solution covers several key steps: first, use a 50T truck crane to lift two specifications of temporary support rigs to the bridge deck and splice them, and reinforce them with stability tie rods and bottom welding; then use a 100T truck crane and a jib truck to assist in lifting the arch ribs in 4 sections and temporarily weld them in place; then use a 50-ton truck crane to install the arch rib secondary rods; then install and tension the hangers from the middle of the overpass to both ends; finally, after the hangers meet the standards, remove the temporary support rigs and install the auxiliary structures.

[0080] The invention has remarkable effects. The innovative temporary support platform provides sufficient support, changing the weak status quo of the support system. The unique fixing method solves the stability problem and reduces construction risks. The platform also realizes precise installation and positioning of the arch ribs, ensuring the smoothness of the arch and improving the aesthetics and structural performance of the pedestrian bridge.

[0081] The technical solutions provided by the embodiments of the present invention are introduced in detail above. Specific examples are used herein to illustrate the principles and implementation methods of the embodiments of the present invention. The description of the above embodiments is only applicable to help understand the principles of the embodiments of the present invention. At the same time, for those skilled in the art, according to the embodiments of the present invention, there will be changes in the specific implementation methods and application scopes. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A construction method for improving the smoothness of the arch rib of a large-span curved steel structure, characterized in that: The following steps are involved: Step S1: After the installation of the overpass box steel beam is completed, a 50T truck crane is used to hoist and set up a temporary support stand for the arch ribs; Step S2, the installed temporary support frame is fixed by bidirectionally pulling the stability tie rods and adding another stability tie rod to pull each other, and the bottom of the temporary support frame is directly welded to the bridge deck; Step S3: After the temporary support frame is installed, a 100T truck crane is used for hoisting and a boom truck is used to assist in installing the arch ribs. The arch ribs on each side are hoisted in 4 sections, and the arch ribs are firmly connected to the temporary support frame by multi-point and multi-directional temporary welding of steel bars; Step S4: After the arch ribs are installed, a 50-ton truck crane is used to hoist and install the arch rib secondary rods; Step S5: After the arch rib secondary rod is installed, the overpass hanger rod is installed and tensioned from the middle to both ends; Step S6: After the overpass suspension rods are installed, the temporary support scaffolding of the bridge face is removed, and the auxiliary structure of the overpass is installed.

2. A construction method for improving the smoothness of the arch rib of a long-span curved steel structure according to claim 1, characterized in that: The temporary support platform includes two types of support frames, 5.355m and 8.055m. The support columns are spliced ​​on the bridge deck with H-shaped steel into a rectangular support frame with a length of 1.5m and a width of 1m. The height of each floor is 1.5m, with a support beam in the middle, a top cantilever length of 1.5m, and an oblique support beam at the bottom.

3. A construction method for improving the smoothness of the arch rib of a long-span curved steel structure according to claim 1, characterized in that: The bridge deck is 30 mm thick, and the weight of a single temporary support stand is 1-2 tons.

4. A construction method for improving the smoothness of the arch rib of a long-span curved steel structure according to claim 1, characterized in that: Before lifting on the temporary support platform, the performance and safety of the 50T truck crane must be checked.

5. The construction method for improving the smoothness of the arch rib of a large-span curved steel structure according to claim 1, characterized in that: When the temporary support scaffold is fixed, after installing the stability rod, the welding part between the bottom of the temporary support scaffold and the bridge deck needs to be cleaned.

6. A construction method for improving the smoothness of the arch rib of a large-span curved steel structure according to claim 1, characterized in that: When installing and temporarily fixing the arch ribs, the balance and stability of the arch ribs must be maintained during the lifting process, and when welding, ensure that each welding point meets the process requirements.

7. A construction method for improving the smoothness of the arch rib of a large-span curved steel structure according to claim 1, characterized in that: When installing the arch rib secondary rods, the installation sequence is determined based on the actual situation on site.

8. The construction method for improving the smoothness of the arch rib of a large-span curved steel structure according to claim 1, characterized in that: When installing the overpass hanger, it is carried out according to the established tension force and position accuracy standards.

9. A construction method for improving the smoothness of the arch rib of a large-span curved steel structure according to claim 1, characterized in that: When dismantling the temporary support scaffolding, measures are taken to avoid damage to the overpass structure and installed components.

10. A construction method for improving the smoothness of the arch rib of a long-span curved steel structure according to any one of claims 1 to 9, characterized in that: The entire construction process is strictly carried out in accordance with the sequence of steps and operational requirements.

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