Spatially shaped steel box girder jig frame and assembling process using the same

Abstract

The application discloses a spatial special-shaped steel box girder jig and an assembling process applying the same, and particularly relates to the technical field of steel box girder construction, which comprises two groups of bottom middle arch feet, two groups of middle arch feet are provided with main arch ribs on the two sides, the overall structure of the main arch rib is in the shape of an inverted V, the inner side of the inverted V structure of the main arch rib is respectively provided with a vice arch rib, the vice arch rib is specifically composed of an inclined rod and a curved rod, the end of the main arch rib is respectively provided with a side arch foot, and the lower side of the main arch rib is sequentially provided with arch rib supports along the stress points of the arc, and the lower side of the arch rib support 5 is provided with a steel box girder. The planar projection is a cubic parabola, the bridge body exhibits unique visual effects under different visual angles, the engineering structure and the artistic aesthetics are perfectly combined, the urban landmark building is formed, and the landscape value and the cultural connotation of the region are improved.

Description

Technical Field

[0001] This application relates to the technical field, and more specifically, to a spatial irregular steel box girder jig and an assembly process using the jig. Background Technology

[0002] When the main span of a large municipal bridge crosses a river navigation channel, the steel box girder segments are usually erected segment by segment using a large floating crane and steel pipe piers. Several large temporary piers are set between two adjacent concrete piers to form multiple navigation channels. The "reverse hole method" is used to erect small temporary piers between adjacent temporary piers. Only one small temporary pier is installed on a navigation channel at a time. The pre-manufactured steel box girder segments are hoisted onto the temporary piers by a large floating crane and the two ends of the steel box girder segments are respectively abutted against the adjacent temporary piers to complete the erection of the steel box girder segments above the navigation channels. After that, the small temporary piers on the navigation channels are removed to restore normal navigation of the navigation channels. The piers are reused for the next navigation channel, and the same steps are used to continue to complete the erection of steel box girder segments at subsequent navigation channels.

[0003] The existing publication number, CN112523111A, discloses a steel box girder hoisting and splicing process. The key technical points of this process include the following steps: Step 1, pre-installation preparation; Step 2, selection of hoisting equipment; Step 3, on-site assembly of the steel box girder; Step 4, hoisting and hoisting process; Step 5, adjustment of the steel box girder position; Step 6, on-site welding of steel box girder segments; and Step 7, unloading of temporary supports. This method effectively reduces the deviation between the steel box girder and its predetermined position, thus improving project quality. During the development of this application, the inventors discovered the following problems with the existing technology:

[0004] Among them, the steel box girder segments were erected segment by segment using a large floating crane and steel pipe pier method. Several large temporary piers were set up between two adjacent concrete piers to form multiple navigation holes. The "inverted hole method" was used to erect small temporary piers between adjacent temporary piers. In the traditional construction method, when erecting the steel box girder segments above the navigation holes, it is necessary to repeatedly insert and pull the steel pipe piles of the temporary piers to realize the installation and removal of the temporary piers. The construction period is long, the cost is large, and it seriously affects the construction progress.

[0005] Therefore, in response to the above problems, a spatial irregular steel box girder jig and an assembly process using the jig are proposed. Summary of the Invention

[0006] In order to overcome the above-mentioned defects of the prior art, this application provides a spatial irregular steel box girder jig and an assembly process using the jig to solve the problems mentioned in the background art.

[0007] To achieve the above objectives, this application provides the following technical solution: a spatial irregular steel box girder formwork, including goose towers, with central arch feet installed at the bottom of both sets of goose towers, and main arch ribs installed on both sides of the two sets of central arch feet. The main arch ribs have an overall herringbone shape, and secondary arch ribs are respectively provided on the inner side of the herringbone structure of the main arch ribs. The secondary arch ribs are specifically composed of diagonal rods and curved rods. Side arch feet are respectively installed at the herringbone ends of the main arch ribs. Arch rib supports are arranged sequentially along the arc stress points below the main arch ribs. A steel box girder is arranged below the arch rib supports. The project includes the lower sections of piers ZP1, ZP2, ZP3, ZP4, and ZP5. A second steel box girder frame is installed in the gap between the lower sections of piers ZP1, ZP2, and ZP3. Two sets of navigation channel steel beams are installed between the lower sections of piers ZP3 and ZP4. A first steel box girder frame is installed between the lower sections of piers ZP4 and ZP5. The tops of the navigation channel steel beams, the first steel box girder frame, and the second steel box girder frame are all fixedly connected to the steel box girder. Navigation channel one, navigation channel two, and navigation channel three are arranged sequentially between the two sets of navigation channel steel beams.

[0008] Preferably, the assembly process of the spatial irregular steel box girder jig includes the following steps:

[0009] S1. Clarify the overall construction plan, determine the segmentation method and technical parameters of the steel beams, complete the dredging of the riverbed, make a cargo supply plan and transportation plan design, select suitable transport vessels and make navigation preparations, and at the same time select and arrange slings;

[0010] S2. Steel box girder installation: Assemble the temporary building structure, install the steel box girders in sequence, and implement positioning and adjustment measures, including the positioning and adjustment of the first steel box girder frame, the second steel box girder frame and the navigation hole steel girder;

[0011] S3. Installation of main arch ribs, secondary arch ribs, and goose towers: Install the main arch ribs, secondary arch ribs, and goose towers in sequence, and implement the positioning and adjustment plan.

[0012] S4. Closure Construction: The closure construction process for the goose tower and the main and auxiliary arch ribs will be carried out separately to complete the closure of key parts;

[0013] S5. Support treatment: Dismantle the navigation channel steel beam, the first steel box girder frame, the second steel box girder frame, and the arch rib support, and address the support settlement issue;

[0014] S6. Component and Transportation Management: Conduct re-inspection and defect handling of incoming components, and ensure safety at all stages of steel box girder transportation, including on-site vessel positioning and implementation of transportation safety measures;

[0015] S7. Welding operations: Implement on-site welding of steel box girders, including on-site welding process operations, as well as weld inspection and non-destructive testing;

[0016] S8. Coating Acceptance: Carry out on-site coating process for steel box girders, conduct anti-corrosion coating construction, control and inspection, and complete construction acceptance.

[0017] Preferably, in step S1, experts are organized to discuss and, in conjunction with the actual engineering conditions and geological conditions, develop an overall construction plan, clarifying the construction sequence, resource allocation, and schedule. Based on the steel beam structure, the riverbed is divided into sections: steel box girder, main and secondary arch ribs, and goose tower. The dimensions, weight, and connection methods of each section are determined, and technical parameters are calculated and clarified. A combination of mechanical and manual dredging is used to comprehensively dredge the riverbed, ensuring that the dredging depth and scope meet design requirements. The dredged silt is transported to a designated spoil heap according to regulations. Then, the supplier's supply batches, timing, and quality standards are confirmed. Multiple steel beam transportation plans are designed and compared. Based on the steel beam dimensions, weight, and transportation route, suitable transport vessels are selected, and sufficient lifting equipment is provided. A detailed survey of the meteorological and hydrological conditions at the construction site is conducted, a navigation plan is developed, and the vessel's communication and navigation equipment is debugged and supplies are replenished. Based on the weight, installation height, and lifting environment of each part of the steel box girder, mechanical calculations and simulation analysis are used to accurately select lifting slings, determine the wire rope specifications, shackle models, and pulley block configurations, and conduct rigorous quality inspections and load tests.

[0018] Preferably, in step S2, the water-based supports for the steel box girder are installed, and the structural construction of the lower parts of piers ZP1 to ZP5 is carried out, while the upstream riverbed of the lower parts of piers ZP4 and ZP5 is dredged; the lower parts of piers ZP1 and ZP5 are installed; simultaneously, the steel box girder, main and secondary arch ribs, and pier towers are processed at the steel structure processing plant; the pier top steel beam of the lower part of pier ZP3 is hoisted using a 660t floating crane, and permanent supports are installed as the reference installation section; the ZP... The steel box girder in the area from the lower part of pier 1 to the lower part of pier ZP3, and all steel beams on the small mileage side of navigation channel one; the steel beam of navigation channel one is installed using a 660t floating crane, and navigation channels two and three are used for temporary passage of vessels in the Dongjiang River; the steel beam at navigation channel two is installed, and navigation channels one and three are used for temporary passage of vessels in the Dongjiang River; the steel beam at navigation channel three is installed, and navigation channels one and two are used for temporary passage of vessels in the Dongjiang River; the steel box girder in the area from the lower part of pier ZP4 to the lower part of pier ZP5 is installed using a 660t floating crane.

[0019] Preferably, in step S3, the single-row column pads and blocks on the right side of the navigation hole are removed to prevent them from participating in later stress; the arch rib support is installed using a 660t floating crane; the lower structure of the goose tower and the arch rib at the middle arch foot are installed using a 660t floating crane; the goose tower tie structure is installed, and the closure line is adjusted; the goose tower closure section is installed; the 660t floating crane is used to install the closure section segment by segment from the arch feet on both sides towards the closure point; the closure section is installed; the arch rib axis, elevation, and verticality of the goose tower are measured using a total station and GPS measuring instruments, and the height of temporary supports and the tension of guy ropes are adjusted in a timely manner during the construction stage to keep the installation error within the design allowable range; after the adjustment is completed, the segment interfaces of the main and auxiliary arch ribs and the goose tower are welded or bolted, and the welding process parameters are strictly controlled during welding; the bolted connections are pre-tightened according to the specifications and quality inspection is carried out.

[0020] Preferably, in step S4, the closure is carried out during a period of stable temperature. The closure section is temporarily fixed at one end, and after the other end is adjusted into place, it is bolted together. During the closure process, the structural deformation and stress changes are monitored in real time. Before installing the closure section, the ends of the arch ribs on both sides are ground to ensure that the interface is flat. After the closure, the arch rib line is monitored, and the support force is adjusted according to the monitoring changes.

[0021] Preferably, in step S5, the support structure is inspected and its auxiliary facilities are removed; a dismantling sequence and safety measures are established, and technical instructions are given to the workers. The dismantling is carried out in sequence according to the construction method of first supporting and then dismantling, and vice versa. The support structure is dismantled step by step using a combination of mechanical and manual methods, and is supervised by a dedicated person to confirm the construction process. The dismantled materials are taken away by a floating crane, and are classified and stacked by a dedicated person and cleaned up from the site in a timely manner. Before the support structure is erected, the foundation is compacted and a cushion layer is laid. During the construction process, the settlement of the support structure is monitored regularly, and if any abnormal settlement is found, the cause is analyzed in a timely manner and the height of the support structure is adjusted accordingly.

[0022] Preferably, in step S6, the steel beam members are processed and fabricated in the factory and the overall trial assembly is completed. After passing the inspection, they are transported to the construction site. After arriving on site, the technical data and physical objects are checked against the design documents, registered and signed by the supervisor. Defects such as twisting and cracks are not allowed and must be repaired by the manufacturing unit. Minor local deformations can be adjusted by hammering with padding plates or cold working with jacks with the approval of the supervisor. Severely damaged parts are returned to the factory for processing. Burrs and welding spatters in the parts to be assembled must be cleaned, removed and polished smooth. Paint damage caused by transportation and handling shall be repaired according to the original factory standard. If rust spots or large-area peeling occurs, the supervisor shall be notified in time to contact the manufacturer for handling.

[0023] Preferably, in step S7, after welding is completed, a designated person cleans the welded area to remove oil and rust; appropriate welding materials and process parameters are selected according to the steel beam material, plate thickness, and welding position; welders receive skills training and assessment, are certified to work, and welding is carried out strictly according to the sequence and method determined by the welding process qualification, using multi-layer, multi-pass welding, and controlling the interpass temperature; quality inspection is strengthened during the welding process, welding defects are corrected in a timely manner, and the weld appearance inspection should show a smooth surface, free of porosity and slag inclusions; ultrasonic testing and radiographic testing are used for non-destructive testing methods, and the welds are inspected according to the proportion required by the design, and unqualified welds are repaired and re-inspected in a timely manner.

[0024] Preferably, in step S8, the steel beam surface is sandblasted to remove rust, achieving the specified cleanliness and roughness standards; the coating system is applied in layers according to the design requirements, including primer, intermediate coat, and topcoat, controlling the thickness and interval of each layer; the ambient temperature and humidity are kept suitable during the coating process, avoiding construction in rainy or windy weather; the coating thickness, adhesion, and appearance quality are checked regularly, and construction records are kept; coating defects are repaired in a timely manner to ensure the anti-corrosion effect; after the coating is completed, relevant units are organized to conduct acceptance, construction data is submitted, and problems raised during the acceptance are rectified and improved; the beam is put into use after passing the acceptance.

[0025] The technical effects and advantages of this application are as follows:

[0026] 1. Compared with existing technologies, the spatial irregular steel box girder formwork and the assembly process using this formwork exhibit highly innovative structural design. The main arch ribs consist of four symmetrical spatial oblique arch ribs, while the secondary arch ribs are spatial curved surface arch ribs. Both the main and secondary arches utilize octagonal cross-sections. This geometric design allows for even load distribution during structural stress. The main arch cross-section features variable height but constant width, with height increases at critical stress points such as the arch feet at the central and side supports. This height increase occurs at approximately 1 / 4 of the arch span. The cross-sectional height is 3.5m, increasing to 5m at the central support arch foot and 6m at the side support arch foot. This gradual design better adapts to stress variations in different areas, ensuring the structure maintains good mechanical performance under vehicle and wind loads. The angle between the diagonal members and the road centerline is 53°, and the spacing between the diagonal members varies from 5.7 to 9.0m. Decorative curved plates welded to the outside of the diagonal members create a feather-like shape, achieving both structural function and artistic appeal. Furthermore, the secondary arch's axis is a spatial curve, its projection on the elevation coinciding with the main arch's axis, and its projection on the plane forming a cubic parabola. This gives the bridge a unique visual effect from different perspectives, perfectly combining structural engineering with artistic aesthetics, making it a landmark building in the city and enhancing the area's landscape value and cultural significance.

[0027] 2. Compared with existing technologies, this spatial irregular steel box girder formwork and its assembly process employ a scientific and reasonable construction plan to ensure efficient and safe project progress. During the construction plan development phase, expert discussions were organized to develop an overall construction plan based on the project's actual conditions and geological features. This plan clarified the construction sequence, resource allocation, and schedule. The steel beam structure was divided into segments, and detailed technical parameters were determined, providing precise guidance for construction. During the steel box girder installation process, a "large segment, multi-block" approach was adopted. The hoisting method utilized a 660t deck-demountable floating crane. Simultaneously, the steel box girder at the navigation channel was manufactured and installed in large longitudinal segments and multiple transverse sections, fully considering the river's navigation requirements and the structural characteristics of the steel box girder. This approach ensured both construction progress and normal river navigation. Regarding construction safety management, strict safety measures were implemented at every stage. During scaffold dismantling, the principle of "support first, dismantle later; support last, dismantle first" was followed, employing a coordinated approach of machinery and manual labor, with dedicated personnel monitoring and detailed dismantling sequence and safety measures. During steel beam transportation, incoming components underwent re-inspection and defect handling, ensuring safety at every stage of transportation, including on-site vessel positioning and the implementation of transportation safety measures. In addition, the structural deformation, stress, and scaffold settlement were monitored in real time during the construction process. For example, the structural deformation and stress changes were monitored in real time during the closure process. Before the scaffold was erected, the foundation was compacted and a cushion layer was laid. The scaffold settlement was monitored regularly during the construction process. Problems were identified and adjustments were made in a timely manner, which effectively ensured the safety and stability of the construction process, avoided the occurrence of safety accidents, and also guaranteed the quality of the project, ensuring that the project could be completed on time and with high quality. Attached Figure Description

[0028] Figure 1 This is a front view of the overall structure of this application;

[0029] Figure 2 This is a top view of the goose tower structure of this application;

[0030] Figure 3 This is a top view of the lower structure of the ZP1 pier in this application;

[0031] Figure 4 This is a front view structural diagram of the lower part of the ZP2 pier in this application;

[0032] Figure 5 This is a top view of the second steel box girder frame of this application;

[0033] Figure 6 This is a side view structural diagram of the steel box girder of this application;

[0034] Figure 7 This is a schematic diagram of the left-side structure of the arch rib support of this application;

[0035] Figure 8 This is a right-side structural schematic diagram of the arch rib support of this application.

[0036] The attached diagram is labeled as follows: 1. Goose Tower; 2. Central Arch Foot; 3. Main Arch Rib; 4. Side Arch Foot; 5. Arch Rib Support; 6. Steel Box Girder; 7. Lower Part of Pier ZP1; 8. Lower Part of Pier ZP2; 9. Lower Part of Pier ZP3; 10. Lower Part of Pier ZP4; 11. Lower Part of Pier ZP5; 12. Navigation Span Steel Beam; 13. First Steel Box Girder Frame; 14. Second Steel Box Girder Frame. Detailed Implementation

[0037] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application. Example 1

[0038] As attached Figures 1 to 8 The spatial irregular steel box girder formwork shown includes two sets of goose towers 1. Each set of two goose towers 1 has a central arch foot 2 installed at its bottom. Main arch ribs 3 are installed on both sides of each set of central arch feet 2. The main arch ribs 3 have a herringbone shape. Secondary arch ribs are provided on the inner side of the herringbone structure of the main arch ribs 3. The secondary arch ribs are specifically composed of diagonal and curved members. Side arch feet 4 are installed at the herringbone ends of the main arch ribs 3. Arch rib supports 5 are arranged sequentially along the arc stress points below the main arch ribs 3. A steel box girder 6 is installed below the arch rib supports 5. Below the steel box girder 6 are the ZP1 pier lower part 7, the ZP2 pier lower part 8, and the ZP3 pier lower part, arranged sequentially. A second steel box girder frame 14 is installed in the gap between the lower part of pier 9, the lower part of pier ZP4 10 and the lower part of pier ZP5 11, the lower part of pier ZP1 7, the lower part of pier ZP2 8 and the lower part of pier ZP3 9. Two sets of navigation channel steel beams 12 are installed between the lower part of pier ZP3 9 and the lower part of pier ZP4 10. A first steel box girder frame 13 is installed between the lower part of pier ZP4 10 and the lower part of pier ZP5 11. The tops of the navigation channel steel beams 12, the first steel box girder frame 13 and the second steel box girder frame 14 are all fixedly connected to the steel box girder 6. Navigation channel one, navigation channel two and navigation channel three are arranged sequentially between the two sets of navigation channel steel beams 12.

[0039] In this application, the bridge structure adopts a 460m long, four-span continuous oblique-span irregular tied arch bridge with an arch-beam connection and a pier-beam separation system. The central pylon 1 is constructed by connecting the pylon 1 to the steel box girder 6. The standard cross-sectional width of the bridge deck is 45m. The bridge deck at the side arch foot 4 is widened to 49.5m as people do not need to walk around the outside of the arch foot. The main beam of the steel box girder 6 has a central beam height of 3.5m. The standard arch span section adopts a separated double small side box + I-beam structure, with box-shaped crossbeams connecting laterally and a hollow top plate. The standard beam span section adopts a semi-enclosed double small side box structure, connected by inverted T-shaped crossbeams. The arch-beam connection zone of the central arch foot 2 and the side arch foot 4 and the side support of the beam span all adopt a fully enclosed whole box structure. The steel box girder 6 consists of three parts: the standard arch span steel beam section, the arch beam node, and the standard beam span steel beam section, with a total of 51 sections.

[0040] The main arch girder steel structure adopts a longitudinally two-stage separated design, consisting of a small side box girder and an I-beam. The standard section of the main arch girder is 144m long, with a standard segment length of 9m. The top slab width of the single-stage separated structure is 20.25m. The small side box girder has a trapezoidal cross-section, with its two webs aligned with the arch foot position. The top slab width is 4.4m, the bottom slab width is 5m, and the cantilever length of the small side box girder is 5.85m. The middle web is a vertical straight web, while the side webs are diagonally inclined, tilting inward at 11°, with the tilt angle coordinated with the cable tension. The I-beam is aligned with the web of the central support arch foot, and the bottom slab width is 0.6m. The clear distance between the small side box girder and the I-beam is 10.25m.

[0041] A box-shaped crossbeam, 3m wide, is installed every 9m, matching the position of the suspension cables, with an open top plate. A solid-web diaphragm and an outer cantilever are installed every 3.0m. The length of the cable-free section of the arch span is 56m, and the standard sections of the arch span steel beams are divided into three types: A1, A2, and A3.

[0042] The standard thickness of the top slab of the arch-span main beam is 16mm, locally thickened to 30mm near the central support and locally thickened to 30mm near the secondary side support; 8mm thick U-ribs with 300mm openings are used under the motor vehicle lanes, with a U-rib spacing of 600mm; 16mm thick plate ribs are used under the sidewalks and non-motor vehicle lanes, with a plate rib spacing of 350mm. The standard thickness of the bottom slab of the main beam is 16mm, locally thickened to 30mm near the central and side supports; the bottom slab uses…

[0043] The bridge arch rib system of this application consists of five parts: main arch rib 3, secondary arch rib, diagonal bar between main and secondary arch rib, curved bar between secondary arch rib and flexible cable between curved bar, as well as decorative components between main arch rib 3 and Goose Tower 1 and decorative components at the tail of side arch.

[0044] The main arch rib 3 consists of four symmetrical spatial diagonal arch ribs, while the secondary arch ribs are spatial curved arch ribs. Both the main and secondary arches adopt octagonal cross sections, while the diagonal and curved members adopt quadrilateral cross sections. Flexible tension cables are used between the curved members to provide in-plane stiffness.

[0045] Four main arches symmetrically span the main beam, converging at the central support and at the side supports, with the main arches tilting symmetrically outwards. Two secondary arches merge into one at the central support and then flow into the main arch, while the two secondary arches flow into the main arch at the side supports. The main and secondary arches are connected by diagonal braces, and the two secondary arches are connected by curved braces and horizontal cables.

[0046] The main arch has a slanted span of 176m and an arch height of 39.404m above the bridge deck. The rise-to-span ratio of the main arch axis is 1 / 4.5. The main arch axis is a cubic curve in plane, and the main arch ribs are symmetrically inclined outward at 5.49° towards the pedestrian side; the secondary arch axis is a spatial curve, and its projection on the elevation coincides with the main arch axis, while its projection on the plane is a cubic parabola.

[0047] Both the main arch and the secondary arch have octagonal cross-sections. The main arch has a variable height but constant width. At approximately 1 / 4 of the arch span, the cross-section height is 3.5m, increasing to 5m at the mid-support side arch foot and to 6m at the side support side arch foot, with a linear change in height between these points. The main arch cross-section width is 2.8m. The secondary arch also has a variable height but constant width. At approximately 1 / 4 of the arch span, the secondary arch has a cross-section height of 2m, increasing to 2.5m at the support position, with a linear change in height between these points. The secondary arch cross-section width is 1.2m. The main arch's web and top / bottom plates are 36–40mm thick, while the secondary arch's top / bottom plates and web are 16mm thick.

[0048] Thirteen diagonal braces are installed between each pair of main and secondary arch ribs, for a total of 52 diagonal braces (4 × 13 = 52). The angle between the diagonal braces and the road centerline is 53°. The spacing between the diagonal braces varies from 5.7 to 9.0 m. The diagonal braces have a box-shaped cross-section, with the web of the diagonal brace aligned with the diaphragm inside the main and secondary arches, and the top and bottom plates of the diagonal brace aligned with the longitudinal stiffening ribs inside the main and secondary arches. The cross-sectional dimensions are 0.8 × 1.0 m. Decorative curved plates are welded to the outside of the diagonal braces to create a feather-like shape on both sides. The thickness of the diagonal brace plates is 16–24 mm.

[0049] Two curved rods with rectangular cross-sections (0.85m x 1.0m) are arranged between the tops of the two secondary arches. The curve lengths of the curved rods are 9.1m and 13.8m, respectively. The thickness of the curved rod plate is 24mm.

[0050] Tower 1 is a planar curved tower column with an octagonal cross-section. The main bridge has 17 pairs of suspension cables arranged radially in a spatial configuration. The tower, a spatial curved column, is 58.866m high above the bridge deck, with a central curved section width of 36.324m. The cross-section of the goose-shaped tower is octagonal; the cross-section width × height at the beak position is 1.566 × 1.63m; the cross-section width × height at the point of maximum offset along the bridge neck is 4.061 × 4.692m; and the cross-section width × height at the base of Tower 1 is 3.219 × 3.306m. The base of Tower 1 is rigidly connected to the main beam, forming a rigid integral node. Example 2

[0051] Based on Example 1, the solution in Example 1 will be further described in detail below with reference to the specific working method, such as... Figures 1 to 8 As shown below, see details:

[0052] S1. Clarify the overall construction plan, determine the segmentation method and technical parameters of the steel beams, complete the dredging of the riverbed, make a cargo supply plan and transportation plan design, select suitable transport vessels and make navigation preparations, and at the same time select and arrange slings;

[0053] S2. Steel box girder installation: Assemble the temporary building structure and install the steel box girder 6 in sequence according to the steps. Implement positioning and adjustment measures, including the positioning and adjustment of the first steel box girder frame 13, the second steel box girder frame 14 and the navigation hole steel beam 12.

[0054] Installation of S3, main arch rib 3, secondary arch rib, and goose tower 1: The installation of the main arch rib, secondary arch rib, and goose tower 1 shall be carried out in sequence, and the positioning and adjustment plan shall be implemented.

[0055] S4. Closure Construction: The closure construction process for Goose Tower 1 and the main and auxiliary arch ribs will be implemented separately to complete the closure of key parts;

[0056] S5. Support treatment: Dismantle the navigation channel steel beam 12, the first steel box girder frame 13, the second steel box girder frame 14, and the arch rib support 5 to address the support settlement issue;

[0057] S6. Component and Transportation Management: Conduct re-inspection and defect handling of incoming components, and ensure safety at all stages of steel box girder transportation, including on-site vessel positioning and implementation of transportation safety measures;

[0058] S7. Welding operations: Implement on-site welding of the steel box girder 6, covering on-site welding process operations, as well as weld inspection and non-destructive testing;

[0059] S8. Coating Acceptance: Carry out the on-site coating process for the steel box girder, conduct anti-corrosion coating construction, control and inspection, and complete the construction acceptance.

[0060] As a preferred implementation method, in step S1, experts are organized to discuss and, in conjunction with the actual engineering conditions and geological conditions, develop an overall construction plan, clarifying the construction sequence, resource allocation, and schedule. Based on the steel beam structure, the riverbed is divided into six sections: the steel box girder, the main and secondary arch ribs, and the goose tower. The dimensions, weight, and connection methods of each section are determined, and the technical parameters are calculated and clarified. A combination of mechanical dredging and manual cleaning is used to thoroughly dredge the riverbed, ensuring that the dredging depth and scope meet the design requirements. The cleaned silt is transported to the designated spoil disposal site in a standardized manner. Then, the batch, time, and quality standards of goods supply are determined with the supplier. Multiple steel beam transportation plans are designed and compared. Based on the steel beam dimensions, weight, and transportation route, suitable transport vessels are selected and sufficient lifting equipment is provided. A detailed survey of the meteorological and hydrological conditions at the construction site is conducted, a navigation plan is formulated, and the debugging of ship communication and navigation equipment and material replenishment are carried out. Based on the weight, installation height, and lifting environment of the six parts of the steel box girder, the lifting slings are accurately selected through mechanical calculations and simulation analysis. The specifications of the wire ropes, the model of the shackles, and the configuration of the pulley blocks are determined, and strict quality inspection and load tests are conducted.

[0061] In a preferred embodiment, in step S2, the water-based support for the steel box girder 6 is installed, and the structural construction of the lower part of pier ZP1 (7-11) is carried out, while the upstream riverbed of the lower part of pier ZP4 (10-11) is dredged; the lower part of pier ZP1 (7-11) is installed; simultaneously, the steel box girder 6, main and secondary arch ribs, and goose tower 1 are processed at the steel structure processing plant; the pier top steel beam of the lower part of pier ZP3 (9) is hoisted using a 660t floating crane, and permanent supports are installed as the reference installation section; the 660t floating crane is used to hoist the steel beam at the top of pier ZP3 (9) and install permanent supports as the reference installation section; The 660t floating crane will install the steel box girder 6 in the area from 7 at the bottom of pier ZP1 to 9 at the bottom of pier ZP3, as well as all the steel beams on the small mileage side of navigation channel one; the 660t floating crane will install the steel beam of navigation channel one, and navigation channels two and three will be used for temporary passage of vessels in the Dongjiang River channel; the 660t floating crane will install the steel beam at navigation channel two, and navigation channels one and three will be used for temporary passage of vessels in the Dongjiang River channel; the 660t floating crane will install the steel box girder 6 in the area from 10 at the bottom of pier ZP4 to 11 at the bottom of pier ZP5.

[0062] In a preferred embodiment, in step S3, the single-row column pads and blocks on the right side of navigation hole three are removed to prevent them from participating in later stress; the arch rib support 5 is installed using a 660t floating crane; the lower structure of Goose Tower 1 and the arch ribs at the middle arch foot 2 are installed using a 660t floating crane; the tie structure of Goose Tower 1 is installed, and the closure line is adjusted; the closure section of Goose Tower 1 is installed; the 660t floating crane is used to install the sections segment by segment from the arch feet on both sides towards the closure point; the closure section is installed; the total station and GPS measuring instruments are used to measure the axis, elevation, and verticality of the arch ribs and Goose Tower 1, and the height of temporary supports and the tension of guy ropes are adjusted at any time during the construction stage to keep the installation error within the design allowable range; after the adjustment is completed, the segment interfaces of the main and auxiliary arch ribs and Goose Tower 1 are welded or bolted, and the welding process parameters are strictly controlled during welding; the bolted connections are pre-tightened according to the specifications and quality inspection is carried out.

[0063] As a preferred embodiment, in step S4, the closure is carried out during a period of stable temperature. The closure section is temporarily fixed at one end, and after the other end is adjusted into place, it is bolted together. During the closure process, the structural deformation and stress changes are monitored in real time. Before installing the closure section, the ends of the arch ribs on both sides are ground to ensure that the interface is flat. After the closure, the arch rib line is monitored, and the support force is adjusted according to the monitoring changes.

[0064] In a preferred embodiment, in step S5, the support structure is inspected and its ancillary facilities are removed. A dismantling sequence and safety measures are established, and technical instructions are given to the workers. The principle of "supporting before dismantling and dismantling the last support first" is followed. The support structure is dismantled gradually using a combination of mechanical and manual methods, with dedicated personnel monitoring and confirming the construction process. The dismantled materials are removed by a floating crane, sorted and stacked by designated personnel, and promptly cleared from the site. Before the support structure is erected, the foundation is compacted and a cushion layer is laid. During construction, the settlement of the support structure is monitored regularly, and any abnormal settlement is analyzed and the support structure height is adjusted accordingly.

[0065] In a preferred embodiment, in step S6, the steel beam members are fabricated in the factory and undergo overall trial assembly. After passing inspection, they are transported to the construction site. Upon arrival, the technical data and physical objects are checked against the design documents, registered, and signed off by the supervisor. Defects such as twisting and cracks are not permitted and must be repaired by the manufacturing unit. Minor local deformations, with the supervisor's approval, can be adjusted by hammering with shims or using jacks for cold adjustment. Severely damaged parts are returned to the factory for processing. Burrs and welding spatter on the parts to be assembled must be cleaned, removed, and polished smooth. Paint damage caused by transportation and handling should be repaired according to the original factory standards. If rust spots or large-area peeling occur, the supervisor should be notified immediately to contact the manufacturer for handling.

[0066] In a preferred embodiment, in step S7, after welding is completed, a designated person cleans the welded area to remove oil and rust; appropriate welding materials and process parameters are selected based on the steel beam material, plate thickness, and welding position; welders receive skills training and assessment, are certified to work, and welding is carried out strictly according to the sequence and method determined by the welding process qualification, using multi-layer, multi-pass welding, and controlling the interpass temperature; quality inspection is strengthened during the welding process, welding defects are corrected in a timely manner, and the weld appearance inspection should show a smooth surface, free of porosity and slag inclusions; ultrasonic testing and radiographic testing are used for non-destructive testing methods, and the welds are inspected according to the proportion required by the design, and unqualified welds are repaired and re-inspected in a timely manner.

[0067] As a preferred embodiment, in step S8, the steel beam surface is sandblasted to remove rust and achieve the specified cleanliness and roughness standards; the coating system is applied in layers according to the design requirements, including primer, intermediate coat, and topcoat, controlling the thickness and interval of each layer; the ambient temperature and humidity are kept suitable during the coating process, and construction is avoided in rainy or windy weather; the coating thickness, adhesion, and appearance quality are checked regularly, and construction records are kept; coating defects are repaired in a timely manner to ensure the anti-corrosion effect; after the coating is completed, relevant units are organized to conduct acceptance, construction data is submitted, and the problems raised during the acceptance are rectified and improved. After passing the acceptance, the beam is put into use.

[0068] The working process of this application is as follows: Three navigation channels are arranged at the bottom of pier ZP3 (9-10 spans below pier ZP4) to ensure navigation. The arrangement of the navigation channels fully considers the influence of the Dongjiang River channel gate. The steel box girder 6 at the navigation channels is manufactured and installed in large longitudinal segments and multiple transverse blocks. After the factory manufacturing is completed, it is pre-assembled under simulated site conditions and then transported by water to the bridge site. The "large segment, multiple block" hoisting is carried out using a 660t deck detachable floating crane. 2.2 Temporary support pier arrangement: The temporary support piers are arranged according to the width of the three 45-meter navigation channels. Three sets of temporary underwater support piers are arranged longitudinally, and three sets of lattice columns are arranged transversely in the bridge direction. One set of lattice columns is set at the bottom of each box girder. The lattice column columns use 820x10mm steel pipes. A three-level distribution beam is set on the upper part of the steel pipe piles for force transmission. Through the Midas whole bridge construction stage modeling analysis, it can be found that the stress requirements of the main beam and subsequent upper arch rib installation are met.

[0069] Longitudinal segmentation: During factory manufacturing, the 145.25-meter steel box girder above the navigation opening was re-divided into segments, longitudinally divided into 48 meters, 51 meters, and 46.25 meters respectively;

[0070] Horizontal segmentation: The horizontal segmentation is divided into 5 sections according to the compartments. Section 1, Section 3, and Section 5 are the compartments, and their on-site installation adopts whole-section hoisting of 48 meters, 51 meters, and 46.25 meters.

[0071] Sections two and four are combinations of crossbeams and bridge deck systems. Considering the deformation caused by their own rigidity during installation, they are installed longitudinally in lengths of 9 to 15 meters during hoisting.

[0072] Because the three compartments of the upper steel box girder 6 of the navigation channel will experience different stresses after installation, resulting in different downward disturbances and rotation angles, the manufacturing process in the factory must follow the pre-calculated and determined schemes for different segments and pre-camber. Segments one, three, and five must be manufactured using the "long-line method" to ensure their alignment. After manufacturing, overall pre-assembly in the factory will be carried out. Before pre-assembly in the factory, a jig should be erected on a site with sufficient foundation bearing capacity. Support points for the lower part of each compartment segment must be erected according to the manufacturing section to ensure that each compartment segment is free of internal stress during assembly. After the jig is erected and measurements are accurate, the pre-assembly of the steel box girder 6 at the navigation channel can begin. The specific process is as follows:

[0073] To simulate the on-site installation sequence, segments one, three, and five were manufactured into small sections and hoisted onto the jig for final assembly. After segments one, three, and five were assembled into a large segment, the jig in the middle of the large segment was unloaded to simulate the stress conditions during on-site installation.

[0074] Hoist segment two and adjust its alignment with the compartment segment. After adjustment, temporarily fix it. Hoist segment four and adjust its alignment with the compartment segment. After adjustment, temporarily fix it.

[0075] After the overall assembly is completed, the overall alignment is measured and evaluated, and compared with the theoretical calculation values. Once the requirements are met, temporary matching parts are installed, and the parts are removed from the mold, painted, and shipped according to the on-site hoisting sections.

[0076] Due to the limitations of the river lock, a 660t floating crane with a detachable deck was selected for lifting. The lifting layout ensured the lifting capacity for all sections. The transport vessel transported the steel beams to the bridge site and anchored perpendicular to the site. After the transport vessel's bow was anchored in a "V" shape, the floating crane sailed to its rear position. The front of the floating crane was secured to the steel pipe piles via anchor chains, and the rear was also anchored in a "V" shape, connecting the transport vessel to the floating crane. After the transport vessel and floating crane were in place, a trial lift was conducted before actual lifting. After the trial lift, the anchor chain on one side of the floating crane was released, and the transport vessel retrieved its anchor and departed the bridge site. The floating crane then moved forward by its rear anchor to the designated beam placement position and re-anchored in a "V" shape. Once anchored, the steel beam was lifted to the designed position, completing the steel beam installation.

[0077] Install steel box girder 6, including steel box girder 6 in the pier area from 9 below pier ZP3 to 10 below pier ZP4, and all steel beams on the small mileage side of the navigation channel;

[0078] The steel beam of the navigation passage was installed using a 660t floating crane. The installation sequence was: side segment 1, middle segment 1, bridge deck system. The bridge deck system was installed from the support point to the mid-span. Navigation passages 2 and 3 are used for temporary passage of vessels in the Dongjiang River channel. Using the 660t floating crane, segments 1 and 3, each 48m in length, were hoisted onto the piers. Fine adjustments were made using three-dimensional jacks, and anti-overturning support measures were installed.

[0079] Using a 660t floating crane, the second section was lifted. There were three lengths: 9m, 12m, and 15m. After the second section was lifted into place, it was positioned and temporarily fixed by matching parts. After the crossbeam was fixed, the hook was released, and the subsequent second sections were lifted in sequence.

[0080] Using a 660t floating crane, section five, 48m in length, was hoisted and anti-overturning bracing was installed. Section four was then hoisted sequentially. After all sections one through five were in place, all welds were welded. Following weld inspection, the circumferential weld between navigation channel one and the pre-erected beam at the lower mileage was then performed.

[0081] Install the steel beam at navigation passage 2. Navigation passages 1 and 3 will be used for temporary passage of vessels in the Dongjiang River. The specific installation steps are the same as for navigation passage 1. Install the steel beam at navigation passage 3. Navigation passages 1 and 2 will be used for temporary passage of vessels in the Dongjiang River. The specific installation steps are the same as for navigation passage 1. After the steel box girder 6 of the navigation passage is installed, continue to install the remaining steel box girder 6 of the side span.

[0082] During the installation of the second navigation channel steel beam 12, the navigation channel support pier 3 was subjected to eccentric load. To prevent the support pier from overturning due to eccentric load, an anti-overturning support point was added to the navigation channel support pier 3, with its elevation 5mm lower than the left support point. During the installation of the second navigation channel steel beam, the deformation of the support pier and the distance between the anti-overturning support point and the steel box girder 6 were monitored in a timely manner. If the load did not automatically transfer to the anti-overturning support point during the deformation of the support pier, a pad was added to the anti-overturning support point to transfer the load to the anti-overturning support point. The box girder was hoisted to the temporary support pier in sections, and after being adjusted into place, it was temporarily fixed to the already erected beam section in a timely manner, and diagonal bracing was welded to ensure its lateral anti-overturning performance. 2.9.2 Anti-collision pier setting: Triangular anti-collision piles were set 5 meters outward from the upstream and downstream of the temporary support piers on both sides of the navigation channel. The triangular anti-collision piers consisted of 3-center 450*8 steel pipe piles and a 428*6 connecting system. The connecting system was arranged in 1 layer every 2 meters high, for a total of 4 layers. Two 1m x 1m warning signs were added to the outside of the steel pipe pile. One warning sign read "Construction ahead, pay attention to safety!" and the other warning sign read "Clear height 10 meters, clear width 45 meters". The above describes the working principle of the spatial irregular steel box girder formwork and the assembly process using this formwork.

Claims

1. The assembly process of a spatial irregular steel box girder jig, characterized by: The assembly process includes the following steps: S1. Clarify the overall construction plan, determine the segmentation method and technical parameters of the steel beams, complete the dredging of the riverbed, make a cargo supply plan and transportation plan design, select suitable transport vessels and make navigation preparations, and at the same time select and arrange slings; S2, Steel box girder installation: Assemble the temporary building structure, install the steel box girder (6) step by step, and implement positioning and adjustment measures, including the positioning and adjustment of the first steel box girder frame (13), the second steel box girder frame (14) and the navigation hole steel beam (12); The steel box girder (6) was installed on the water support, and the structural construction of the lower part of ZP1 pier (7) to the lower part of ZP5 pier (11) was carried out. According to the construction sequence, navigation holes 1, 2 and 3 appeared in sequence in the lower part of the pier. The riverbed of the lower part of ZP4 pier (10) to the lower part of ZP5 pier (11) was dredged. The lower part of ZP1 pier (7) to the lower part of ZP5 pier (11) was installed. The steel box girder (6), main arch rib, secondary arch rib and goose tower (1) were processed in the steel structure processing plant respectively. The lower part of ZP3 pier was hoisted by a 660t floating crane. (9) The steel beam at the top of the pier is installed with permanent supports as the reference installation section; the steel beam of the navigation channel one is installed using a 660t floating crane; during the installation, the navigation channels two and three are kept open for temporary passage of ships; the steel beam at the navigation channel two is installed, and the navigation channels one and three are used for temporary passage of ships in the channel; the steel beam at the navigation channel three is installed, and the navigation channels one and two are used for temporary passage of ships in the channel; the steel box girder (6) in the area of ​​the lower part (10) of pier ZP4 to the lower part (11) of pier ZP5 is hoisted into place using a 660t floating crane; S3, main arch rib (3), secondary arch rib, and goose tower (1) installation: carry out the installation of the main arch rib, secondary arch rib and goose tower (1) in sequence, and implement the positioning and adjustment plan; Remove the single-row column pads and blocks on the right side of the navigation hole three so that they do not participate in the later stress; use a 660t floating crane to install temporary arch rib supports (5); use a 660t floating crane to install the lower structure of the goose tower (1) and the arch rib at the middle arch foot (2); install the tie structure of the goose tower (1) and adjust the closure line; install the closure section of the goose tower (1); use a 660t floating crane to install section by section from the arch feet on both sides towards the closure, and finally install the closure section; use a total station and GPS measuring instruments to measure the axis, elevation and verticality of the arch ribs and the goose tower (1), and adjust the height of the temporary support and the tension of the cable at any time during the construction stage; after the adjustment is completed, weld or bolt the segment interfaces of the main and secondary arch ribs and the goose tower (1); S4. Closure construction: The closure construction process of the goose tower (1) and the main and auxiliary arch ribs shall be implemented respectively to complete the closure of key parts; S5. Support treatment: Dismantle the navigation channel steel beam (12), the first steel box girder frame (13), the second steel box girder frame (14) and the arch rib support (5) to deal with the support settlement problem; S6. Component and Transportation Management: Re-inspect and handle defects of incoming components, and ensure safety in all aspects of steel box girder (6) transportation, including on-site ship positioning and implementation of transportation safety measures; S7. Welding operations: Implement on-site welding of steel box girders (6), covering on-site welding process operations, as well as weld inspection and non-destructive testing; S8. Coating Acceptance: Carry out on-site coating process for steel box girders (6), carry out anti-corrosion coating construction, control and inspection, and complete construction acceptance.

2. The assembly process of the spatial irregular steel box girder jig according to claim 1, characterized in that: In step S1, experts were organized to discuss and, in combination with the actual engineering conditions and geological conditions, a general construction plan was prepared, clarifying the construction sequence, resource allocation and schedule. Based on the steel beam structure, the steel box girder (6), main and secondary arch ribs and goose tower (1) were divided into sections. The dimensions, weight and connection method of each section were determined, the technical parameters were confirmed, and the riverbed was dredged by a combination of mechanical dredging and manual cleaning. The dredged silt was transported to the designated spoil disposal site. Then, the batch, time and quality standards of goods supply were determined with the supplier. Based on the dimensions, weight and transportation route of the steel beam, multiple transportation plans were designed. After comparison, the transportation vessel was determined and hoisting equipment was equipped. The meteorological and hydrological conditions at the construction site were investigated, a navigation plan was formulated, and the ship communication and navigation equipment was debugged and the material supply was replenished. Based on the weight, installation height and hoisting environment of each part of the steel box girder (6), the appropriate hoisting slings were selected through mechanical calculation and simulation analysis. The specifications of the wire rope, the model of the shackle and the configuration of the pulley block were determined.

3. The assembly process of the spatial irregular steel box girder jig according to claim 1, characterized in that: In step S4, the closure is carried out during a period of stable temperature. The closure section is temporarily fixed at one end, and after the other end is adjusted into place, it is bolted together. During the closure process, the structural deformation and stress changes are monitored in real time. Before installing the closure section, the ends of the arch ribs on both sides are ground to ensure that the interface is flat. After the closure, the shape of the arch ribs is monitored, and the force on the support is adjusted according to the monitoring changes.

4. The assembly process of the spatial irregular steel box girder jig according to claim 1, characterized in that: In step S5, the scaffolding is inspected and its auxiliary facilities are removed. A dismantling sequence and safety measures are established, and technical instructions are given to the workers. The dismantling is carried out in the order of construction, following the principle of "first support, then dismantle" and "last support, first dismantle." The scaffolding is dismantled gradually using a combination of mechanical and manual labor, with dedicated personnel monitoring and confirming the construction process. The dismantled materials are removed by a floating crane, sorted and stacked by designated personnel, and promptly cleared from the site. Before the scaffolding is erected, the foundation is compacted and a cushion layer is laid. During construction, the settlement of the scaffolding is monitored, and if abnormal settlement is detected, the height of the scaffolding is adjusted.

5. The assembly process of the spatial irregular steel box girder jig according to claim 1, characterized in that: In step S6, the steel beam members are processed and fabricated in the factory and the overall trial assembly is completed. After passing the inspection, they are transported to the construction site. After arriving on site, the technical data and physical objects are checked against the design documents, registered and signed by the supervisor. If unacceptable defects are found, the manufacturing unit shall repair them. Minor local deformations can be adjusted by hammering with padding plates or cold straightening with jacks with the approval of the supervisor. Severely damaged parts are returned to the factory for processing. Burrs and welding spatters in the parts to be assembled must be cleaned, removed and polished smooth. Paint damage caused by transportation and handling shall be repaired according to the original factory standard. If rust spots or large-area peeling occurs, the supervisor shall be notified to contact the manufacturer for handling.

6. The assembly process of the spatial irregular steel box girder jig according to claim 1, characterized in that: In step S7, after welding is completed, a designated person cleans the welded area to remove oil and rust. Based on the steel beam material, plate thickness, and welding position, appropriate welding materials and process parameters are selected, multi-layer and multi-pass welding is adopted, and the interpass temperature is controlled. The weld appearance should be smooth, free of porosity and slag inclusion defects. Non-destructive testing methods such as ultrasonic testing or radiographic testing are used to inspect the weld according to the design requirements.

7. The assembly process of the spatial irregular steel box girder jig according to claim 1, characterized in that: In step S8, the steel beam surface is sandblasted to remove rust and achieve the specified cleanliness and roughness standards. The coating system is applied in layers according to the design requirements, including primer, intermediate coat, and topcoat, with control over the thickness and interval between each layer. During the coating process, the ambient temperature and humidity are kept suitable, and construction is avoided in rainy or windy weather. The coating thickness, adhesion, and appearance quality are regularly checked, and construction records are kept. Coating defects are repaired promptly to ensure anti-corrosion effect. After coating is completed, the relevant unit conducts acceptance testing, and construction documents are submitted. Problems raised during acceptance are rectified and improved, and the beam is put into use after passing the inspection.

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