A through-type tied arch bridge and its installation method

Abstract

The present invention relates to a bottom-supported tie-bar arch bridge, comprising arch ribs, box-type wind bracing, hangers, tie beams, cross beams and small longitudinal beams. The present invention also relates to a method for installing a bottom-supported tie-bar arch bridge, comprising the following steps: (1) pre-assembling and welding the various components that have been produced and processed at a prefabrication site; (2) dismantling the various segments after the pre-assembly and transporting them to the construction site; (3) performing installation and construction on site; (4) after the installation is completed, dismantling the main bridge assembly bracket and temporary bracket. The present invention can ensure the welding quality of bridge components, eliminate internal residual stress, avoid the generation of welding cracks, control deformation and improve processing accuracy, and ensure that various welding properties meet the design requirements of the bridge; the installation method ensures that the various structural components of the arch bridge are accurately aligned, the assembly accuracy is high, and the linear shape of the installed bottom-supported tie-bar arch bridge is accurate.

Description

Technical Field

[0001] The present invention relates to the technical field of bridge engineering construction, and in particular to a through-type tied arch bridge and an installation method thereof. Background Art

[0002] A through-type tied-arch bridge utilizes tie cables to balance the horizontal thrust of the arch foot. This structure combines large spans with strong adaptability to foundation conditions. The main arch of a through-type tied-arch bridge exhibits significant vertical stiffness, and the vertical support provided by the suspenders ensures that the main girder meets the required vertical stiffness.

[0003] However, through-the-wall tied-arch bridges typically feature long spans and numerous, heavy structural components. This creates significant engineering challenges during the production and installation of these components, which can easily lead to welding quality issues and difficulty controlling the overall linear shape of the tied-arch bridge structure. Welding quality issues typically include the generation of internal residual stresses and weld cracks, while linear shape control difficulties often stem from inaccurate component machining and assembly, resulting in inaccurate component alignment and an inability to ensure linear accuracy. Over time, these issues can severely impact the structural strength and stability of through-the-wall tied-arch bridges.

[0004] Therefore, there is an urgent need to provide an improved bottom-supported tie-arch bridge and a related installation method to solve the above-mentioned series of problems existing in the prior art. Summary of the Invention

[0005] To address the shortcomings of the prior art, the present invention provides a through-type tie-arch bridge and its installation method. This invention ensures the welding quality of bridge components, eliminates internal residual stress, prevents weld cracks, controls deformation, and improves machining accuracy, ensuring that all welding properties meet the design requirements of the bridge. The installation method also ensures precise alignment between the various arch bridge components, high assembly accuracy, and an accurate linear profile for the completed through-type tie-arch bridge.

[0006] To achieve the above object, the present invention provides a through-type tied arch bridge, comprising arch ribs, box-type wind bracing, hangers, tie beams, cross beams and small longitudinal beams;

[0007] Two arch ribs are used, each of which is a box-shaped arch rib with a uniform cross-section. Box-shaped wind bracing is arranged between the arch ribs. Tie beams are connected to the arch ribs at the arch foot, and the arch ribs and tie beams are connected by hangers. The hangers include middle hangers and end hangers, both made of epoxy steel strands. The cross beams include end cross beams and middle cross beams. The end cross beams are arranged between the tie beams and at both ends of the tie beams. Multiple middle cross beams are spaced apart within the frame space enclosed by the tie beams and end cross beams. Multiple small longitudinal beams are arranged between the tie beams along the direction of the tie beams.

[0008] There are multiple diaphragms in the arch rib, including ordinary diaphragms, suspender diaphragms, wind-bracing diaphragms and semicircular diaphragms. The suspender diaphragms and wind-bracing diaphragms are solid-web diaphragms, while the ordinary diaphragms and semicircular diaphragms are frame-type diaphragms.

[0009] The tie beam adopts a box-shaped section and is internally provided with transverse members, including web vertical ribs, tie beam common transverse diaphragms and hanger cross diaphragms. The tie beam common transverse diaphragms and hanger cross diaphragms are solid-web transverse diaphragms. The tie beam common transverse diaphragms and hanger cross diaphragms are evenly spaced and provided with web vertical ribs in between.

[0010] The box-type wind bracing includes a top plate, a bottom plate, a web plate, a wing plate and stiffening ribs, and a plurality of frame-type cross partitions are also arranged inside the box-type wind bracing.

[0011] Preferably, the epoxy steel strand is composed of multiple steel wires wrapped together, and the outside of each steel wire is coated with a first epoxy anti-corrosion coating. When the multiple steel wires are wrapped together, the second epoxy anti-corrosion material is used to impregnate the wrapped multiple steel wires as a whole, so that the second epoxy anti-corrosion material fills the gaps between the multiple steel wires and covers the wrapped multiple steel wires as a whole. Finally, the entire outside of the epoxy steel strand is wrapped with an anti-corrosion sheath.

[0012] In any of the above schemes, it is preferred that 6 box-type wind braces are arranged between the arch ribs; 4 27-strand Φ15.2 prestressed tie rods are arranged in each tie beam; the middle hanger adopts 27-strand Φ15.2 epoxy steel strands, and the end hanger adopts 31-strand Φ15.2 epoxy steel strands; horizontal connecting supports are arranged between adjacent beams to form a truss, and the horizontal connecting supports adopt an I-shaped section; sidewalk cantilevers are arranged on the outside of the tie beam, with a width of 2.5m and a height of 0.5m.

[0013] In any of the above schemes, it is preferred that the semicircular diaphragm is arranged at the position of the arch rib near the arch foot, which is a frame-type semicircular structure spliced with multiple support rods to improve the overall strength and stability of the arch rib structure near the arch foot; the hanger diaphragm is a solid-web diaphragm with a U-shaped structure to ensure the strength of the connection between the hanger and the arch rib; the wind-bracing diaphragm adopts a solid-web diaphragm with a box-type structure to ensure the strength of the connection between the box-type wind brace and the arch rib; the ordinary arch rib diaphragm is arranged at other corresponding positions inside the arch rib.

[0014] In any of the above schemes, it is preferred that the various components of the bottom-supported tie-arch bridge are processed by automatic welding, the welding of the cross-partition adopts the standing welding method of reverse carbon planing and root cleaning combined with flux-cored wire CO2 gas shielded welding, and the welding of other components adopts the horizontal welding method of ceramic pad heating combined with solid wire CO2 gas shielded welding for bottoming and submerged arc welding for covering.

[0015] In any of the above schemes, it is preferred that after the components of the bottom-supported tie-arch bridge are processed, they are subjected to surface anti-corrosion coating treatment, the outer surface of each component is sandblasted to Sa2.5 level, the surface roughness is Rz40-80μm, and the coating from inside to outside is 80μm thick cold-sprayed zinc, 2 cold-sprayed zinc sealing primers with a thickness of 100μm each, 5 epoxy iron oxide paints with a thickness of 150μm each, 1 40μm thick acrylic aliphatic polyurethane topcoat, and 1 40μm thick fluorocarbon topcoat.

[0016] In any of the above schemes, it is preferred that when performing surface anti-corrosion coating treatment, the inner surface of the steel beam of each component is sandblasted to Sa2.5 level, with a surface roughness of Rz40-80μm, and the coating from the inside to the outside is 1 coat of 60μm thick epoxy zinc-rich primer, 3 coats of 120μm thick epoxy micaceous iron paint each, and 1 coat of 80μm thick epoxy high-paste paint.

[0017] In addition, the present invention also provides a method for installing a through-type tied arch bridge, comprising the following steps:

[0018] (1) The processed components are pre-assembled and welded in the prefabrication yard. According to the segment division of the main bridge body, the single-side steel arch is divided into 5 segments, and the entire bridge is divided into 10 segments. The segments are assembled and welded on the assembly frame in a matching round of half a span. This includes the pre-assembly and welding of the arch rib segments and the pre-assembly and welding of the bridge deck segments.

[0019] (2) After the pre-assembly is completed, the segments are dismantled and transported to the construction site. During transportation, sleepers are placed on the carriage, and the segments are placed on the sleepers. When setting the sleepers, the tail of the segment is higher than the head, and the overhang of the tail of the segment is less than 6m. To prevent the segment from moving sideways, limit blocks are welded between the two sides of the segment and the carriage, and the segment is tied to the carriage with a fall chain.

[0020] (3) On-site installation and construction; use a 400t floating crane and a 400t truck crane to complete the construction of the main bridge assembly bracket; use the main bridge assembly bracket and the 400t floating crane to install the main arch feet and bridge deck system segments on both sides; install the main arch rib assembly temporary bracket, and use the 400t floating crane to install the arch rib segments and hangers;

[0021] (4) After installation is completed, remove the main bridge assembly bracket and temporary bracket.

[0022] Preferably, in the step (3), the installation includes adopting a welding process. In order to improve labor productivity and reduce costs, submerged arc automatic welding and CO2 gas shielded welding are adopted, and manual arc welding is adopted for positioning welding; to ensure welding quality, an arc strike plate is installed at the beginning and end of the weld, and the weld groove on the arc strike plate is the same as the main weld groove and is made of the same material. The arc strike plate of the manual arc welding is not shorter than 35 mm; after welding, the arc strike plate is cut off at a distance of 3 to 5 mm from the base material using oxyacetylene gas cutting, and the connection is polished smooth with a grinding wheel.

[0023] In any of the above schemes, it is preferred that deformation monitoring is also installed in step (3), including checking whether the segment hoisted in place is consistent with the control points and control lines, using a total station to verify whether the coordinates of the segment hoisted in place are consistent with the design drawing, and verifying whether the elevation of the segment hoisted in place is consistent with the design elevation.

[0024] Beneficial effects of the present invention:

[0025] 1. The present invention can ensure the welding quality of bridge components, eliminate internal residual stress, avoid the generation of welding cracks, control deformation and improve processing accuracy, and ensure that various welding performances meet the design requirements of the bridge; the installation method ensures that the various structural members of the arch bridge are accurately aligned, the assembly accuracy is high, and the linear shape of the installed bottom-supported tie arch bridge is accurate.

[0026] 2. The present invention can effectively shorten the construction period, reduce capital investment, have good economic benefits, and reduce the overall cost of the project; the high degree of mechanization reduces the labor intensity of workers, ensures construction quality, and at the same time reduces the impact of environmental factors on construction operations, greatly shortening the construction time of bridge construction; ensures transportation stability and structural stability during on-site installation operations.

[0027] 3. The overall structure of the present invention is simple and easy to operate; it can ensure the anti-corrosion performance of the overall bridge structure, improve installation accuracy, reduce construction safety risks, and extend the service life of the bottom-supported tie-arch bridge. DETAILED DESCRIPTION

[0028] The technical solution of the present application will be described in detail below in conjunction with the specific implementation methods of the present application, but the following examples are only for understanding the present invention. The embodiments and features in the embodiments of the present application can be combined with each other, and the present application can be implemented in a variety of different ways as defined and covered by the claims.

[0029] Example 1

[0030] A bottom-through tied arch bridge comprises arch ribs, box-type wind bracing, hangers, tie beams, cross beams and small longitudinal beams;

[0031] Two arch ribs are used, each of which is a box-shaped arch rib with a uniform cross-section. Box-shaped wind bracing is arranged between the arch ribs. Tie beams are connected to the arch ribs at the arch foot, and the arch ribs and tie beams are connected by hangers. The hangers include middle hangers and end hangers, both made of epoxy steel strands. The cross beams include end cross beams and middle cross beams. The end cross beams are arranged between the tie beams and at both ends of the tie beams. Multiple middle cross beams are spaced apart within the frame space enclosed by the tie beams and end cross beams. Multiple small longitudinal beams are arranged between the tie beams along the direction of the tie beams.

[0032] There are multiple diaphragms in the arch rib, including ordinary diaphragms, suspender diaphragms, wind-bracing diaphragms and semicircular diaphragms. The suspender diaphragms and wind-bracing diaphragms are solid-web diaphragms, while the ordinary diaphragms and semicircular diaphragms are frame-type diaphragms.

[0033] The tie beam adopts a box-shaped section and is internally provided with transverse members, including web vertical ribs, tie beam common transverse diaphragms and hanger cross diaphragms. The tie beam common transverse diaphragms and hanger cross diaphragms are solid-web transverse diaphragms. The tie beam common transverse diaphragms and hanger cross diaphragms are evenly spaced and provided with web vertical ribs in between.

[0034] The box-type wind bracing includes a top plate, a bottom plate, a web plate, a wing plate and stiffening ribs, and a plurality of frame-type cross partitions are also arranged inside the box-type wind bracing.

[0035] The epoxy steel strand is composed of multiple steel wires wrapped together, and the outside of each steel wire is coated with a first epoxy anti-corrosion coating. When the multiple steel wires are wrapped together, the second epoxy anti-corrosion material is used to impregnate the wrapped multiple steel wires as a whole, so that the second epoxy anti-corrosion material fills the gaps between the multiple steel wires and covers the wrapped multiple steel wires as a whole. Finally, the entire outside of the epoxy steel strand is wrapped with an anti-corrosion sheath.

[0036] Six box-type wind braces are arranged between the arch ribs; four 27-strand Φ15.2 prestressed tie rods are installed in each tie beam; the middle hanger adopts 27-strand Φ15.2 epoxy steel strands, and the end hanger adopts 31-strand Φ15.2 epoxy steel strands; horizontal connecting supports are arranged between adjacent beams to form a truss, and the horizontal connecting supports adopt an I-shaped section; sidewalk cantilevers are arranged on the outside of the tie beams, with a width of 2.5m and a height of 0.5m.

[0037] The semicircular diaphragm is arranged at the position of the arch rib near the arch foot. It is a frame-type semicircular structure spliced with multiple support rods to improve the overall strength and stability of the arch rib structure near the arch foot; the hanger diaphragm is a solid-web diaphragm with a U-shaped structure to ensure the strength of the connection between the hanger and the arch rib; the wind-bracing diaphragm adopts a solid-web diaphragm with a box-type structure to ensure the strength of the connection between the box-type wind brace and the arch rib; the ordinary diaphragm of the arch rib is arranged at other corresponding positions inside the arch rib.

[0038] The various components of the bottom-supported tie-arch bridge are processed by automatic welding. The welding of the cross-partition adopts the standing welding method of reverse carbon planing and CO2 gas shielded welding with flux-cored wire. The welding of other components adopts the horizontal welding method of ceramic pad heating combined with solid wire CO2 gas shielded welding for bottoming and submerged arc welding for covering.

[0039] After processing, the components of the bottom-supported tie-arch bridge are subjected to surface anti-corrosion coating. The outer surface of each component is sandblasted to Sa2.5 level and the surface roughness is Rz40μm. The coating from inside to outside is 80μm thick cold-sprayed zinc, 2 coats of cold-sprayed zinc sealing primer with a thickness of 100μm each, 5 coats of epoxy micaceous iron paint with a thickness of 150μm each, 1 coat of 40μm thick acrylic aliphatic polyurethane topcoat, and 1 coat of 40μm thick fluorocarbon topcoat.

[0040] During the surface anti-corrosion coating treatment, the inner surface of the steel beams of each component is sandblasted to Sa2.5 level, with a surface roughness of Rz80μm. The coating from inside to outside is 1 coat of 60μm thick epoxy zinc-rich primer, 3 coats of 120μm thick epoxy micaceous iron paint each, and 1 coat of 80μm thick epoxy high-paste paint.

[0041] Example 2

[0042] A bottom-through tied arch bridge comprises arch ribs, box-type wind bracing, hangers, tie beams, cross beams and small longitudinal beams;

[0043] Two arch ribs are used, each of which is a box-shaped arch rib with a uniform cross-section. Box-shaped wind bracing is arranged between the arch ribs. Tie beams are connected to the arch ribs at the arch foot, and the arch ribs and tie beams are connected by hangers. The hangers include middle hangers and end hangers, both made of epoxy steel strands. The cross beams include end cross beams and middle cross beams. The end cross beams are arranged between the tie beams and at both ends of the tie beams. Multiple middle cross beams are spaced apart within the frame space enclosed by the tie beams and end cross beams. Multiple small longitudinal beams are arranged between the tie beams along the direction of the tie beams.

[0044] There are multiple diaphragms in the arch rib, including ordinary diaphragms, suspender diaphragms, wind-bracing diaphragms and semicircular diaphragms. The suspender diaphragms and wind-bracing diaphragms are solid-web diaphragms, while the ordinary diaphragms and semicircular diaphragms are frame-type diaphragms.

[0045] The tie beam adopts a box-shaped section and is internally provided with transverse members, including web vertical ribs, tie beam common transverse diaphragms and hanger cross diaphragms. The tie beam common transverse diaphragms and hanger cross diaphragms are solid-web transverse diaphragms. The tie beam common transverse diaphragms and hanger cross diaphragms are evenly spaced and provided with web vertical ribs in between.

[0046] The box-type wind bracing includes a top plate, a bottom plate, a web plate, a wing plate and stiffening ribs, and a plurality of frame-type cross partitions are also arranged inside the box-type wind bracing.

[0047] The epoxy steel strand is composed of multiple steel wires wrapped together, and the outside of each steel wire is coated with a first epoxy anti-corrosion coating. When the multiple steel wires are wrapped together, the second epoxy anti-corrosion material is used to impregnate the wrapped multiple steel wires as a whole, so that the second epoxy anti-corrosion material fills the gaps between the multiple steel wires and covers the wrapped multiple steel wires as a whole. Finally, the entire outside of the epoxy steel strand is wrapped with an anti-corrosion sheath.

[0048] Six box-type wind braces are arranged between the arch ribs; four 27-strand Φ15.2 prestressed tie rods are installed in each tie beam; the middle hanger adopts 27-strand Φ15.2 epoxy steel strands, and the end hanger adopts 31-strand Φ15.2 epoxy steel strands; horizontal connecting supports are arranged between adjacent beams to form a truss, and the horizontal connecting supports adopt an I-shaped section; sidewalk cantilevers are arranged on the outside of the tie beams, with a width of 2.5m and a height of 0.5m.

[0049] The semicircular diaphragm is arranged at the position of the arch rib near the arch foot. It is a frame-type semicircular structure spliced with multiple support rods to improve the overall strength and stability of the arch rib structure near the arch foot; the hanger diaphragm is a solid-web diaphragm with a U-shaped structure to ensure the strength of the connection between the hanger and the arch rib; the wind-bracing diaphragm adopts a solid-web diaphragm with a box-type structure to ensure the strength of the connection between the box-type wind brace and the arch rib; the ordinary diaphragm of the arch rib is arranged at other corresponding positions inside the arch rib.

[0050] The various components of the bottom-supported tie-arch bridge are processed by automatic welding. The welding of the cross-partition adopts the standing welding method of reverse carbon planing and CO2 gas shielded welding with flux-cored wire. The welding of other components adopts the horizontal welding method of ceramic pad heating combined with solid wire CO2 gas shielded welding for bottoming and submerged arc welding for covering.

[0051] After the processing of the components of the bottom-supported tie-arch bridge is completed, the surface anti-corrosion coating is carried out. The outer surface of each component is sandblasted to Sa2.5 level, with a surface roughness of Rz80μm. The coating from the inside to the outside is 80μm thick cold-sprayed zinc, 2 coats of cold-sprayed zinc sealing primer with a thickness of 100μm each, 5 coats of epoxy micaceous iron paint with a thickness of 150μm each, 1 coat of 40μm thick acrylic aliphatic polyurethane topcoat, and 1 coat of 40μm thick fluorocarbon topcoat.

[0052] During the surface anti-corrosion coating treatment, the inner surface of the steel beams of each component is sandblasted to Sa2.5 level, with a surface roughness of Rz40μm. The coating from inside to outside is 1 coat of 60μm thick epoxy zinc-rich primer, 3 coats of 120μm thick epoxy micaceous iron paint each, and 1 coat of 80μm thick epoxy high-paste paint.

[0053] In addition, in order to further improve the technical effect of the present invention, in this embodiment, the first epoxy anti-corrosion coating includes the following components in parts by weight: 75 parts of bisphenol A epoxy resin emulsion, 18 parts of sodium lauryl sulfate, 32 parts of aminobenzene, 19 parts of ammonium persulfate solution, 37 parts of dimethyl ketone, 16 parts of methanol, 23 parts of ammonium nitrate, and 22 parts of microcrystalline kaolin powder.

[0054] The second epoxy anti-corrosion coating includes the following components in parts by weight: 43 parts of epoxy resin E-44, 24 parts of polyamide wax slurry, 19 parts of barite powder, 21 parts of o-xylene, and 4 parts of silane coupling agent.

[0055] The first and second epoxy anti-corrosion coatings form a thin oxide film on the surface of the steel wire, which increases the corrosion resistance and reduces the corrosion rate of the steel strand. This effect is spread over the entire surface of the steel wire, thus giving the steel strand excellent corrosion resistance.

[0056] Taking the epoxy steel strand produced by a company in Guizhou as a comparative example, the epoxy steel strand prepared by the present invention and the epoxy steel strand in the comparative example were subjected to performance tests, and the test results are shown in Table 1.

[0057] Test method:

[0058] The corrosion resistance test is carried out using the salt spray test method;

[0059] The tensile strength test is carried out according to the standard of GB / T228.1.

[0060] Table 1

[0061] Test items The present invention Comparative Example Corrosion resistance high medium Tensile strength (MPa) 2650 1380 Surface corrosion after 6 months Uniform and smooth surface Obvious rust

[0062] It can be seen that the epoxy steel strand used in the present invention has good corrosion resistance, high tensile strength and good mechanical properties.

[0063] The U-shaped opening of the solid-web transverse diaphragm of the U-shaped structure faces downward, toward the connection point of the hanger rod, and is welded to the inside of the arch rib. An inverted V-shaped support piece is provided inside the U-shaped structure, and the top and bottom ends of the two inclined support pieces are respectively welded to the inside of the transverse diaphragm of the U-shaped structure.

[0064] The above-mentioned structural form of the hanger cross diaphragm is simple and stable. The hanger end connected to the arch rib can be clamped therein, which can effectively protect the hanger end from damage, prevent the connection between the hanger and the arch rib from being damaged and cracked due to force, avoid failure of the connection between the two, and ensure the stability of the overall structure.

[0065] The box-like, solid-web transverse bulkhead comprises two parallel outer support bulkheads, arranged perpendicular to the length of the arch ribs and forming a box-like structure with the interior of the arch ribs, and three evenly spaced inner support bulkheads, arranged parallel to and between the outer support bulkheads. The inner sides of the two outer support bulkheads are provided with a plurality of diagonal support rods extending along the length of the outer support bulkheads, while each inner support bulkhead is provided with a plurality of diagonal support rods extending along the length of the inner support bulkhead on both sides. Reinforced connectors are provided within the top and bottom plates of the arch ribs to reinforce the top and bottom of the outer and inner support bulkheads, respectively. The ends of the outer and inner support bulkheads are welded to the interior of the arch ribs.

[0066] The wind bracing diaphragm of the above-mentioned structural form has a simple structure and a stable connection. It can form a connection state similar to an extended socket with the box-type wind bracing connected to the arch rib, further strengthening the strength of the connection between the wind bracing and the arch rib, and ensuring the stability of the overall structure.

[0067] Example 3

[0068] A method for installing a through-type tied arch bridge comprises the following steps:

[0069] (1) The processed components are pre-assembled and welded in the prefabrication yard. According to the segment division of the main bridge body, the single-side steel arch is divided into 5 segments, and the entire bridge is divided into 10 segments. The segments are assembled and welded on the assembly frame in a matching round of half a span. This includes the pre-assembly and welding of the arch rib segments and the pre-assembly and welding of the bridge deck segments.

[0070] (2) After the pre-assembly is completed, the segments are dismantled and transported to the construction site. During transportation, sleepers are placed on the carriage, and the segments are placed on the sleepers. When setting the sleepers, the tail of the segment is higher than the head, and the cantilever of the tail of the segment is 6m. To prevent the segment from moving sideways, limit blocks are welded between the two sides of the segment and the carriage, and the segment is tied to the carriage with a fall chain.

[0071] (3) On-site installation and construction; use a 400t floating crane and a 400t truck crane to complete the construction of the main bridge assembly bracket; use the main bridge assembly bracket and the 400t floating crane to install the main arch feet and bridge deck system segments on both sides; install the main arch rib assembly temporary bracket, and use the 400t floating crane to install the arch rib segments and hangers;

[0072] (4) After installation is completed, remove the main bridge assembly bracket and temporary bracket.

[0073] In the step (3), the installation includes adopting a welding process. In order to improve labor productivity and reduce costs, submerged arc automatic welding and CO2 gas shielded welding are adopted, and manual arc welding is adopted for positioning welding; to ensure welding quality, an arc strike plate is installed at the beginning and end of the weld, and the weld groove on the arc strike plate is the same as the main weld groove and is made of the same material. The arc strike plate for manual arc welding is 35 mm; after welding, the arc strike plate is cut off at a distance of 3 mm from the base material using oxyacetylene gas cutting, and the connection is polished smooth with a grinding wheel.

[0074] In step (3), deformation monitoring is also installed, including checking whether the segments hoisted into place are consistent with the control points and control lines, using a total station to verify whether the coordinates of the segments hoisted into place are consistent with the design drawings, and verifying whether the elevation of the segments hoisted into place is consistent with the design elevation.

[0075] Example 4

[0076] A method for installing a through-type tied arch bridge comprises the following steps:

[0077] (1) The processed components are pre-assembled and welded in the prefabrication yard. According to the segment division of the main bridge body, the single-side steel arch is divided into 5 segments, and the entire bridge is divided into 10 segments. The segments are assembled and welded on the assembly frame in a matching round of half a span. This includes the pre-assembly and welding of the arch rib segments and the pre-assembly and welding of the bridge deck segments.

[0078] (2) After the pre-assembly is completed, the segments are dismantled and transported to the construction site. During transportation, sleepers are placed on the carriage, and the segments are placed on the sleepers. When setting the sleepers, the tail of the segment is higher than the head, and the cantilever of the tail of the segment is 5m. To prevent the segment from moving sideways, limit blocks are welded between the two sides of the segment and the carriage, and the segment is tied to the carriage with a fall chain.

[0079] (3) On-site installation and construction; use a 400t floating crane and a 400t truck crane to complete the construction of the main bridge assembly bracket; use the main bridge assembly bracket and the 400t floating crane to install the main arch feet and bridge deck system segments on both sides; install the main arch rib assembly temporary bracket, and use the 400t floating crane to install the arch rib segments and hangers;

[0080] (4) After installation is completed, remove the main bridge assembly bracket and temporary bracket.

[0081] In the step (3), the installation includes adopting a welding process. In order to improve labor productivity and reduce costs, submerged arc automatic welding and CO2 gas shielded welding are adopted, and manual arc welding is adopted for positioning welding; to ensure welding quality, an arc strike plate is installed at the beginning and end of the weld, and the weld groove on the arc strike plate is the same as the main weld groove and is made of the same material. The arc strike plate for manual arc welding is 38 mm; after welding, the arc strike plate is cut off at a distance of 5 mm from the base material using oxyacetylene gas cutting, and the connection is polished smooth with a grinding wheel.

[0082] In step (3), deformation monitoring is also installed, including checking whether the segments hoisted into place are consistent with the control points and control lines, using a total station to verify whether the coordinates of the segments hoisted into place are consistent with the design drawings, and verifying whether the elevation of the segments hoisted into place is consistent with the design elevation.

[0083] Furthermore, to further enhance the technical benefits of this invention, in this embodiment, stress relief is achieved by hammering and mechanical vibration during on-site segment installation. After welding, locations with significant residual stress and deformation are relieved using external force and flame straightening. The flame straightening is maintained at a stable temperature of 600-800°C, followed by natural cooling at room temperature.

[0084] In addition, accurate alignment and line accuracy must be ensured during hoisting and alignment, so requirements must be placed on component processing accuracy and assembly accuracy, namely:

[0085] ① According to the construction conditions and strengthening construction monitoring, a monitoring and measurement system for the entire bridge was established based on the set observation points. Precision measurement tools such as total stations were used to assist in installation, accurately locate the assembly positions, and mark the measurement positions.

[0086] ② Develop a reasonable welding sequence and method to control welding deformation and prevent the ports from being misaligned.

[0087] ③ When placing the frame, accurately control the placement according to the measurement marks at both ends during assembly, and use a jack to adjust it forward and backward, left and right for precise adjustment. During construction, fine-tune the frame repeatedly in the order of vertical adjustment - horizontal adjustment - vertical adjustment - vertical adjustment - horizontal adjustment - vertical adjustment until the design requirements are met.

[0088] ④ After all segments are in place, the elevations are rechecked. Segments with incorrect deck elevations are adjusted using jacks and other equipment until the deck elevation meets the design requirements. During this process, attention must be paid to the longitudinal and transverse positions of the beam segments to avoid secondary adjustments.

[0089] During the pre-assembly of the arch rib segments, the linear shape must be controlled to ensure the matching accuracy of the ports. During the pre-assembly of the segments, the relative positions of the adjacent segments are consistent with the linear shape when the arch bridge segments are hoisted. Therefore, the pre-assembly of the segments is mainly to further check the ports and overall linear shape between the adjacent segments to avoid large gaps and large misalignments between the segments during on-site welding, so that the on-site welding work can proceed smoothly. The pre-assembly between segments not only needs to check the gaps and adjust the misalignments, but also needs to match the port sizes and make necessary corrections and adjustments. After the pre-assembly inspection of the segments is qualified, various marks such as the longitudinal center line of the segments, temporary lifting points, transverse inspection lines of the ports, and elevation measurement points when the segments are hoisted on the bridge are drawn according to the process requirements using instruments and tools such as laser theodolites and steel belts.

[0090] During pre-assembly of bridge deck segments, the pre-assembly alignment of the tie beams must be consistent with the overall bridge alignment, with strict control over longitudinal camber. The ends and joints of adjacent main beams must be consistent. A pre-assembly cradle is used during assembly. The pre-assembly cradle is constructed based on the cradle and landmarks, drawing segmented pre-assembly landmarks. These include segmented longitudinal and transverse positioning lines, anchor plate positioning lines, and end inspection lines. The cradle alignment is verified using a theodolite. Pre-assembly support points are arranged, closing control points are set, angle steel support points are welded, and precision cutting is performed.

[0091] The temporary support is based on steel pipe piles, with transverse distribution beams placed on top of the steel pipe piles and supporting short column segments placed above the distribution beams. The steel pipe piles are made of Φ630mm*8 spiral pipes.

[0092] Steel pipe pile construction

[0093] Before sinking, the coordinates of each steel pipe pile were calculated. A baseline was laid out for each pile on the embankment. Each observation point on the baseline was precisely measured using a total station, and its elevation was measured using a level. The coordinates and intersection angles of each observation point on each pile were then calculated and compiled into a table for use during pile sinking observations. During sinking, a total station was deployed on the front for observation and positioning, and two theodolites were set up on the sides for verification. A 125kW vibratory hammer, capable of providing a rated vibration force of 125t, was used for sinking the steel pipe piles.

[0094] The first guide pile is driven in using a pile driver (with a built-in bite). Subsequent steel pipes are positioned according to the guide pile, determining the positions of other piles for subsequent steel pipe column support installation. During the installation process, two traction ropes and the pile driver itself are used to stabilize the pile for precise positioning. Theodolites are installed directly in front of and to the side of the pile driver to monitor the verticality of the pile frame, ensuring the pile remains upright. Once the pile has achieved a certain degree of stability, a vibrating pile driver is used to clamp the steel pipe pile and begin vibrating it down into position.

[0095] When sinking steel pipe piles, the following precautions should be taken: the center of the vibrating hammer and the central axis of the pile should be aligned as closely as possible. Each pile should be sunk continuously, without prolonged pauses to prevent soil friction from recovering and hindering further sinking. Observe the sinking process closely. Pipe pile deviation should not exceed 10 cm. Pile tilt is permitted during construction, but should be less than 1% of L (L is the pile length). High-strain testing should be used to verify that the steel pipe pile's bearing capacity meets requirements.

[0096] Steel pipe pile precision control

[0097] The driving accuracy of steel pipe piles mainly depends on the positioning accuracy and verticality of the first section of steel piles (i.e., the lower section of the pile). After the first section of steel piles is hoisted and positioned, it will slowly sink in the soil due to the weight of the pile body, pile cap, and pile hammer. Hammering will not begin until the steel pipe pile is stable and no longer sinks. During the driving process, the pile sinking records recorded by the instrument should be closely observed. If any problems are found, the driving process should be stopped immediately, the cause should be identified, and the deviation should be corrected in a timely manner. If the deviation is too large or cannot be corrected, the pipe pile should be pulled out and reinserted, and a rigid guide frame should be set up to ensure that the pipe pile is sunk according to the design requirements.

[0098] Steel pipe pile connection

[0099] When connecting steel pipe piles, align the upper section with the sunken lower section, ensuring close contact between the joint sleeves. Once this is achieved, spot weld the sections first, followed by welding the circumferential seam. To ensure smooth installation of the sections, guide and positioning devices must be installed between the sections. Guide lugs are installed on the outer wall of the pile. These lugs serve as temporary lifting lugs during installation and also as guides for the pile.

[0100] It can be seen from the above embodiments that the present invention can ensure the welding quality of bridge components, eliminate internal residual stress, avoid the generation of welding cracks, control deformation and improve processing accuracy, and ensure that various welding performances meet the design requirements of the bridge; the installation method ensures that the various structural components of the arch bridge are accurately positioned, the assembly accuracy is high, and the linear shape of the installed bottom-supported tie arch bridge is accurate.

[0101] The present invention can effectively shorten the construction period, reduce capital investment, have good economic benefits, and reduce the overall cost of the project; the high degree of mechanization reduces the labor intensity of workers, ensures construction quality, and at the same time reduces the impact of environmental factors on construction operations, greatly shortening the construction time of the bridge; and ensures transportation stability and structural stability during on-site installation operations.

[0102] The present invention has a simple overall structure and is easy to operate; it can ensure the anti-corrosion performance of the overall bridge structure, improve installation accuracy, reduce construction safety risks, and extend the service life of the bottom-supported tie-arch bridge.

[0103] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any other manner. Any person skilled in the art may utilize the above-disclosed technical content to modify or modify the present invention into equivalent embodiments. However, any simple modifications, equivalent variations, and modifications to the above embodiments that do not depart from the technical content of the present invention and are based on the technical essence of the present invention remain within the scope of protection of the present invention.

Claims

1. A through-type tied arch bridge, characterized in that: Including arch ribs, box wind bracing, hangers, tie beams, cross beams and small longitudinal beams; Two arch ribs are used, each of which is a box-shaped arch rib with a uniform cross-section. Box-shaped wind bracing is arranged between the arch ribs. Tie beams are connected to the arch ribs at the arch foot, and the arch ribs and tie beams are connected by hangers. The hangers include middle hangers and end hangers, both made of epoxy steel strands. The cross beams include end cross beams and middle cross beams. The end cross beams are arranged between the tie beams and at both ends of the tie beams. Multiple middle cross beams are spaced apart within the frame space enclosed by the tie beams and end cross beams. Multiple small longitudinal beams are arranged between the tie beams along the direction of the tie beams. There are multiple diaphragms in the arch rib, including ordinary diaphragms, suspender diaphragms, wind-bracing diaphragms and semicircular diaphragms. The suspender diaphragms and wind-bracing diaphragms are solid-web diaphragms, while the ordinary diaphragms and semicircular diaphragms are frame-type diaphragms. The tie beam adopts a box-shaped section and is internally provided with transverse members, including web vertical ribs, tie beam common transverse diaphragms and hanger cross diaphragms. The tie beam common transverse diaphragms and hanger cross diaphragms are solid-web transverse diaphragms. The tie beam common transverse diaphragms and hanger cross diaphragms are evenly spaced and provided with web vertical ribs in between. The box-type wind bracing includes a top plate, a bottom plate, a web plate, a wing plate and stiffening ribs, and a plurality of frame-type cross partitions are also arranged inside the box-type wind bracing.

2. The through-type tie-arch bridge according to claim 1, characterized in that: The epoxy steel strand is composed of multiple steel wires wrapped together, and the outside of each steel wire is coated with a first epoxy anti-corrosion coating. When the multiple steel wires are wrapped together, the second epoxy anti-corrosion material is used to impregnate the wrapped multiple steel wires as a whole, so that the second epoxy anti-corrosion material fills the gaps between the multiple steel wires and covers the wrapped multiple steel wires as a whole. Finally, the entire outside of the epoxy steel strand is wrapped with an anti-corrosion sheath.

3. The through-type tie-arch bridge according to claim 2, characterized in that: Six box-type wind braces are arranged between the arch ribs; four 27-strand Φ15.2 prestressed tie rods are installed in each tie beam; the middle hanger adopts 27-strand Φ15.2 epoxy steel strands, and the end hanger adopts 31-strand Φ15.2 epoxy steel strands; horizontal connecting supports are arranged between adjacent beams to form a truss, and the horizontal connecting supports adopt an I-shaped section; sidewalk cantilevers are arranged on the outside of the tie beams, with a width of 2.5m and a height of 0.5m.

4. The through-type tie-arch bridge according to claims 1-3, characterized in that: The semicircular diaphragm is arranged at the position of the arch rib near the arch foot. It is a frame-type semicircular structure spliced with multiple support rods to improve the overall strength and stability of the arch rib structure near the arch foot; the hanger diaphragm is a solid-web diaphragm with a U-shaped structure to ensure the strength of the connection between the hanger and the arch rib; the wind-bracing diaphragm adopts a solid-web diaphragm with a box-type structure to ensure the strength of the connection between the box-type wind brace and the arch rib; the ordinary diaphragm of the arch rib is arranged at other corresponding positions inside the arch rib.

5. The through-type tied arch bridge according to claim 4, characterized in that: The various components of the bottom-supported tie-arch bridge are processed by automatic welding. The welding of the cross-partition adopts the standing welding method of reverse carbon planing and CO2 gas shielded welding with flux-cored wire. The welding of other components adopts the horizontal welding method of ceramic pad heating combined with solid wire CO2 gas shielded welding for bottoming and submerged arc welding for covering.

6. The through tie arch bridge according to claim 5, characterized in that: After processing, the components of the bottom-supported tie-arch bridge are subjected to surface anti-corrosion coating. The outer surface of each component is sandblasted to Sa2.5 level, with a surface roughness of Rz40-80μm. The coating from inside to outside is 80μm thick cold-sprayed zinc, 2 coats of cold-sprayed zinc sealing primer with a thickness of 100μm each, 5 coats of epoxy micaceous iron paint with a thickness of 150μm each, 1 coat of 40μm thick acrylic aliphatic polyurethane topcoat, and 1 coat of 40μm thick fluorocarbon topcoat.

7. The through tie arch bridge according to claim 5-6, characterized in that: During the surface anti-corrosion coating treatment, the inner surface of the steel beams of each component is sandblasted to Sa2.5 level, with a surface roughness of Rz40-80μm. The coating from inside to outside is 1 coat of 60μm thick epoxy zinc-rich primer, 3 coats of 120μm thick epoxy micaceous iron paint each, and 1 coat of 80μm thick epoxy high-paste paint.

8. A method for installing a through-type tied arch bridge according to claims 1-7, characterized in that: The following steps are involved: (1) The processed components are pre-assembled and welded in the prefabrication yard. According to the segment division of the main bridge body, the single-side steel arch is divided into 5 segments, and the entire bridge is divided into 10 segments. The segments are assembled and welded on the assembly frame in a matching round of half a span. This includes the pre-assembly and welding of the arch rib segments and the pre-assembly and welding of the bridge deck segments. (2) After the pre-assembly is completed, the segments are dismantled and transported to the construction site. During transportation, sleepers are placed on the carriage, and the segments are placed on the sleepers. When setting the sleepers, the tail of the segment is higher than the head, and the overhang of the tail of the segment is less than 6m. To prevent the segment from moving sideways, limit blocks are welded between the two sides of the segment and the carriage, and the segment is tied to the carriage with a fall chain. (3) On-site installation and construction; use a 400t floating crane and a 400t truck crane to complete the construction of the main bridge assembly bracket; use the main bridge assembly bracket and the 400t floating crane to install the main arch feet and bridge deck system segments on both sides; install the main arch rib assembly temporary bracket, and use the 400t floating crane to install the arch rib segments and hangers; (4) After installation is completed, remove the main bridge assembly bracket and temporary bracket.

9. The method for installing a through-type tied arch bridge according to claim 8, characterized in that: In the step (3), the installation includes adopting a welding process. In order to improve labor productivity and reduce costs, submerged arc automatic welding and CO2 gas shielded welding are adopted, and manual arc welding is adopted for positioning welding; to ensure welding quality, an arc strike plate is installed at the beginning and end of the weld, and the weld groove on the arc strike plate is the same as the main weld groove and is made of the same material. The arc strike plate of the manual arc welding is not shorter than 35 mm; after welding, the arc strike plate is cut off at a distance of 3 to 5 mm from the base material using oxyacetylene gas cutting, and the connection is polished smooth with a grinding wheel.

10. The method for installing a through-type tied arch bridge according to claim 9, characterized in that: In step (3), deformation monitoring is also installed, including checking whether the segments hoisted into place are consistent with the control points and control lines, using a total station to verify whether the coordinates of the segments hoisted into place are consistent with the design drawings, and verifying whether the elevation of the segments hoisted into place is consistent with the design elevation.