Half-through mesh hanger arch bridge and its construction method

Abstract

The present invention discloses a mid-span lattice-suspended arch bridge, comprising curved arch ribs on either side of the bridge deck structure, lattice-suspended rods connecting the arch ribs and the bridge deck structure, and arch columns. Multiple cross braces are provided between the arch ribs, each constructed from butted hollow steel tubes coated with a CA-UHPC outer layer. CA-UHPC is introduced into the arch ribs of the lattice-suspended arch bridge, and the CA-UHPC material and steel tubes are combined to provide the arch bridge with a strong spanning capacity, efficient force bearing, and quick and easy construction. Using this arch bridge in engineering construction can overcome common shortcomings of long-span concrete arch bridges, such as the excessive deadweight of large-span concrete arch bridges, the difficulty and high cost of welding thick steel plates in all-steel arch bridges, and CFST arch bridges.

Description

Technical Field

[0001] The present invention relates to the field of hanger arch bridges, and in particular to a mid-span reticular hanger arch bridge and a construction method thereof. Background Art

[0002] Ultra-High Performance Concrete (UHPC) is widely used in bridge engineering around the world for its excellent mechanical properties and durability. However, the expensive material cost of UHPC and the high requirements for construction technology hinder its large-scale application. At present, because UHPC is used according to traditional structural forms and design theories, its excellent performance and potential benefits have not been fully utilized. UHPC is mainly used in bridge engineering for cast-in-place wet joints of traditional precast concrete components, bridge deck pavement and repair of damaged bridges. Although traditional UHPC can improve the strength of concrete materials in reinforced concrete composite structures, its elastic modulus increases less than that of ordinary concrete. It is still difficult to fully utilize the mechanical properties of each material when used as a composite structure, which limits further breakthroughs in the lightweighting of steel-concrete composite bridge structures.

[0003] Concrete-Filled Steel Tube (CFST) arch bridges are a common long-span arch bridge structure. However, the outer surface of the steel tubes is directly exposed to the atmosphere, making them susceptible to rust. This leads to significant corrosion problems and high maintenance costs during operation. Furthermore, CFST arch bridges typically utilize a self-erecting construction method, where the main arch steel tube structure is erected first, and then concrete is poured into the tubes after they are closed. However, this construction method subjects the steel tubes to considerable initial stress before the concrete solidifies. Furthermore, the shrinkage and creep effects of concrete cause the compressive stress borne by the concrete to be gradually transferred to the steel tubes. This effect further increases the compressive stress in the steel tubes, causing them to be subjected to high stress while the concrete material cannot fully realize its advantages.

[0004] Therefore, a mesh-type hanger arch bridge is needed to overcome the shortcomings of large-span concrete arch bridges, such as the excessive weight, high cost of thick steel plates, and difficulty in welding of all-steel arch bridges, as well as the shortcomings of CFST arch bridges. Summary of the Invention

[0005] In view of this, the purpose of the present invention is to overcome the defects in the prior art and provide a half-through reticular hanger arch bridge and a construction method thereof. CA-UHPC is introduced into the arch ribs of the reticular hanger arch bridge and CA-UHPC material is combined with steel pipes to make the arch bridge have the advantages of strong spanning capacity, high force efficiency, fast and simple construction, and less maintenance work during operation. The problems of excessive deadweight of long-span concrete arch bridges, high cost of thick steel plates of all-steel arch bridges, great welding difficulty, and CFST arch bridges are solved.

[0006] The mid-through reticular hanger arch bridge of the present invention comprises arcuate arch ribs located on both sides of the bridge deck structure, and reticular hangers and arch columns connecting the arch ribs and the bridge deck structure. A plurality of cross braces are provided between the arch ribs. The arch ribs are formed by butting together hollow steel tubes, the outer surface of which is covered with a layer of CA-UHPC outer cladding. The hangers above the bridge deck and below the arch ribs are arranged in parallel and cross each other. The hangers above the bridge deck and below the arch ribs are arranged in parallel and cross each other at least twice. The arch columns below the bridge deck and above the arch ribs are arranged in an oblique and cross-distributed manner. The hangers and arch columns are connected at nodes by inner structural reinforcement.

[0007] Furthermore, shear nails are radially arranged at the interface between the hollow steel pipe and the CA-UHPC outer cladding, and the shear nails are evenly distributed along the circumference of the CA-UHPC outer cladding. Stirrups are provided on the outer surface of the CA-UHPC outer cladding, and longitudinal steel bars are evenly distributed circumferentially inside the CA-UHPC outer cladding.

[0008] Furthermore, the hollow steel tubes of the main arch rib segments are precisely aligned by flange butt connection and connected by butt welding. The mesh slings are anchored in the hollow steel tubes. The connection nodes of the cross braces, arch columns and hollow steel tubes are all provided with stiffening plates, which are located in the hollow steel tubes.

[0009] Furthermore, the longitudinal ends of the arch rib are fixed to the arch seat, an inverted V-shaped side pier is fixedly connected between the arch seat and the bridge deck structure, and the arch rib is relatively inclined inward to form a basket arch structure;

[0010] Furthermore, the cross brace is composed of four rods, one end of which intersects and is fixedly connected as a whole, and the other ends are obliquely connected to four different positions on the arch rib;

[0011] Furthermore, the intersection and fixing point of the four rods is located at 1 / 4 of the longitudinal length of the cross brace;

[0012] Furthermore, the arch rib is connected to the arch seat through an arch hinge structure to realize a double-hinge arch structure system and reduce the additional bending moment of the arch foot. The arch hinge structure consists of an upper concave hemispherical structure, a lower convex hemispherical structure, and a sliding pair located between the upper concave hemispherical structure and the lower convex hemispherical structure. The upper concave hemispherical structure and the lower convex hemispherical structure are matched in a concave and convex manner and can slide relative to each other along the hemispherical surface. The lower convex hemispherical structure realizes force diffusion and transmission to the arch seat through the CA-UHPC pad.

[0013] The present invention discloses a construction method for a half-through mesh hanger arch bridge, comprising the following steps:

[0014] (1) Prefabricated arch rib segments are erected using an arch crane. Before the arch ribs are closed, temporary inclined cables are used to assist the main arch ribs in bearing stress. After the main arch structure is formed, the temporary inclined cables are gradually removed.

[0015] (2) The arch columns, rigid hangers, mesh cables and bridge deck structures are constructed in sections from the shore to the mid-span;

[0016] (3) Install the precast concrete bridge deck, then tension the mesh cables, adjust the overall line shape of the bridge deck structure, cast the bridge deck in-situ wet joints, symmetrically remove the temporary cable stays and temporary towers, and complete the construction of the main bridge structure;

[0017] Furthermore, the construction method of the arch rib comprises the following steps:

[0018] S1. Prefabricated arch rib segments are manufactured in the factory. After the inner hollow steel tubes are manufactured, the CA-UHPC outer layer is poured and steam cured.

[0019] S2. Use a transport barge to transport the prefabricated arch rib segments from the factory to the bridge site and hoist them using an arch crane;

[0020] S3. The use of on-site butt flanges provided in the inner steel pipe ends of the prefabricated arch rib segments is achieved by accurately positioning the prefabricated arch rib segments to be installed, and the inner steel pipe is butt-welded on-site after the installation line meets the requirements;

[0021] S4. After the inner steel pipe welding is completed and the flaw detection is qualified, the CA-UHPC cast-in-place joint is cast on site and steam cured on site.

[0022] Beneficial effects of the present invention: The mid-span reticular hanger arch bridge of the present invention introduces CA-UHPC into the arch ribs of the reticular hanger arch bridge and combines CA-UHPC materials with steel pipes, so that the arch bridge has the characteristics of strong spanning capacity, high force efficiency, and fast and easy construction, solving the problems of excessive deadweight of large-span concrete arch bridges, high cost of thick steel plates of all-steel arch bridges, difficult welding, and CFST arch bridges.

[0023] The mid-through mesh hanger arch bridge of the present invention has the following advantages:

[0024] (1) Expanded the types of lattice hanger arch bridge structural systems and their applicability to terrain conditions. Through innovation in the structural system, the additional bending moment of the main arch is minimized as much as possible, so that the main arch is mainly responsible for bearing axial forces, thereby fully utilizing the most outstanding mechanical properties of CA-UHPC, namely compression performance. Due to the reduction in bending moment, the stress distribution in the main arch section is more uniform, so the arch rib cross-sectional size, wall thickness and cross-sectional area can be significantly reduced, thereby achieving the purpose of reducing the deadweight of the structure and making full use of materials, and significantly improving the structural efficiency and economy of this bridge type.

[0025] (2) The arch ribs are of circular hollow cross-section, with simple structure and easy manufacturing. The advantages of the composite composite structure are fully utilized, allowing the outer layer of CA-UHPC to bear most of the arch axis pressure, so as to minimize the thickness of the inner hollow steel tube and avoid the welding of thick steel plates. Compared with the all-steel arch bridge, the maximum thickness of the bridge steel plate of the present invention can be controlled within 40 mm (the welded structure of the steel plate not exceeding 40 mm is an easy-to-weld structure), which can improve the construction quality and engineering economy. At the same time, the hollow steel tube also serves as a construction template, which greatly simplifies the construction process and reduces construction measures.

[0026] (3) CA-UHPC, a green and environmentally friendly building material, is used in the main arch structure, which saves more material than conventional concrete materials. In addition, by fully utilizing the advantage of the low unit carbon dioxide emission index in the production process of UHPC materials (when subjected to the same axial force N, the carbon emission of UHPC is only 0.2 times that of steel and 0.35 times that of conventional concrete), carbon dioxide emissions can be significantly reduced.

[0027] (4) Taking full advantage of the excellent durability of CA-UHPC can not only significantly extend the service life of the structure and reduce maintenance and repairs, but also make the bridge more green and energy-efficient throughout its life cycle.

[0028] (5) The mid-span mesh hanger arch bridge of the present invention carves out the shape of the arch with simple and slender lines, which can achieve overall harmony, coordinated proportions, and beautiful and generous effects, allowing the bridge to be well integrated into the surrounding environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The present invention will be further described below in conjunction with the accompanying drawings and embodiments:

[0030] Figure 1 This is the elevation layout of a mid-through lattice-type hanger arch bridge;

[0031] Figure 2 This is a cross-section of a mid-span lattice hanger arch bridge;

[0032] Figure 3 A three-dimensional axial perspective view of a half-through mesh hanger arch bridge according to an embodiment of the present invention;

[0033] Figure 4 for Figure 3 A partial enlarged view of point A in the middle;

[0034] Figure 5 for Figure 3 A partial enlarged view of point B in the middle;

[0035] Figure 6 for Figure 3 A partial enlarged view of point D in the middle;

[0036] Figure 7This is a cross-sectional arrangement diagram of the main arch ribs of a half-through mesh hanger arch bridge according to an embodiment of the present invention;

[0037] Figure 8 3D schematic diagram of the main arch rib segment connection joints of a half-through reticular hanger arch bridge according to an embodiment of the present invention;

[0038] Figure 9 for Figure 3 A partial enlarged view of point A in the middle;

[0039] Figure 10 3D schematic diagram of a typical segment of the deck structure of a half-through lattice hanger arch bridge according to an embodiment of the present invention;

[0040] Figure 11 A typical cross-sectional view of the deck structure of a half-through lattice-type hanger arch bridge according to an embodiment of the present invention;

[0041] Figure 12 3D schematic diagram of the structure below the bridge deck of a half-through lattice hanger arch bridge according to an embodiment of the present invention;

[0042] Figure 13 3D schematic diagram of the arch hinge structure of a half-through reticular hanger arch bridge according to an embodiment of the present invention;

[0043] Figure 14 for Figure 13 A partial enlarged view of point A in the middle;

[0044] Figure 15 for Figure 13 A schematic diagram of the partially enlarged three-dimensional decomposition structure at point B in the middle;

[0045] Figure 16 Schematic diagram of the construction steps of a mesh hanger arch bridge.

[0046] The above drawings include the following reference numerals: 1—arch rib, 2—cross brace, 3—arch seat, 4—bridge deck structure, 5—side pier, 6—bridge abutment, 7—net hanger, 8—rigid hanger, 9—arch column, 10—arch hinge structure, 11—precast arch rib segment, 12—CA-UHPC cast-in-place joint, 31—enlarged foundation, 32—vertical pile, 33—inclined pile, 41—side box steel main beam, 42—small longitudinal beam, 43—hollow cross diaphragm, 44—cantilevered sidewalk, 45—precast concrete bridge deck, 46—cast-in-place wet joint, 91—pin hinge, 101—upper concave hemispherical structure, 102—lower convex hemispherical structure, 103— —Sliding pair, 104—CA-UHPC pad, 111—Hollow steel pipe, 112—Cable anchorage structure, 113—CA-UHPC outer cladding, 114—Shear studs, 115—Longitudinal reinforcement, 116—Stirrups, 117—On-site butt flange, 118—Flange stiffener, 119—Column stiffening structure, 120—Transverse bracing stiffener, 121—End stiffener, 122—End pad, 123—Connecting bolt, 124—Anchor bolt, 201—Temporary tower, 202—Temporary diagonal stay cable, 203—Arch crane, 204—Temporary ground anchor, 205—Transport barge, 206—Girder crane. DETAILED DESCRIPTION

[0047] The mid-span lattice-suspended arch bridge of this embodiment includes curved arch ribs on either side of a bridge deck structure 4, lattice-suspended rods 7 connecting the arch ribs and the bridge deck structure 4, and arch columns 9. Multiple cross braces 2 are positioned between the arch ribs. The arch ribs are formed by butting together hollow steel tubes 111, each coated with a CA-UHPC outer layer 113. The cross braces 2 of the main arch 1 and the arch columns 9 are steel components, connected to the inner hollow steel tubes 111 of the arch ribs by welding. The CA-UHPC outer layer 113 protects the inner steel tubes from corrosion, providing them with excellent durability. The longitudinal reinforcement 115 and inner steel tubes within the CA-UHPC outer layer 113 increase the arch rib structure's bending bearing capacity. Furthermore, the inner steel tubes also serve as construction formwork, reducing construction requirements.

[0048] UHPC has outstanding advantages such as high strength, high elastic modulus, high durability, high toughness, high density, and low creep. However, UHPC's low elastic modulus and significant creep characteristics are key factors limiting breakthroughs in lightweight steel-concrete composite bridge structures. For traditional UHPC under natural curing conditions, its total shrinkage can reach 700με, and the creep coefficient is generally 0.8. Its significant autogenous shrinkage characteristics will lead to uncertainty in the long-term stress distribution of traditional steel-UHPC composite structures. CA-UHPC, by adopting selective adsorption polymers, introducing anionic combing surfactants, and using in-situ grafting technology of hydrophobic segments, can reduce the total shrinkage deformation of 700d to 300με and the creep coefficient to 0.35, which can further improve the performance of the composite structure.

[0049] The arch rib structure utilizes a new CA-UHPC-steel hollow tube composite component, which exhibits superior compressive and corrosion resistance. The substantial axial pressure borne by the circular hollow-section arch rib structure is shared between the CA-UHPC outer cladding 113 and the inner steel tube. In the CA-UHPC-steel hollow tube component, the CA-UHPC outer cladding 113 bears the majority of the pressure. This design significantly reduces the thickness of the inner steel tube, avoiding the need for welding thick steel plates. For arch structures, stability generally controls the load-bearing capacity. Material near the center of the section has limited function, resulting in low material utilization. Therefore, a hollow section is preferred for arch structures. By adopting a larger hollow ratio, the amount of CA-UHPC used and the deadweight of the structure can be significantly reduced. The arch ribs utilize prefabricated arch rib segments 11. The CA-UHPC outer cladding 113 between adjacent segments is connected via cast-in-place CA-UHPC joints 12, while the inner hollow steel tube 111 is connected via on-site butt welding.

[0050] In this embodiment, shear studs 114 are radially installed at the interface between the hollow steel tube 111 and the CA-UHPC outer cladding 113. These studs 114 are evenly distributed along the circumference of the CA-UHPC outer cladding 113. Stirrups 116 are located on the outer surface of the CA-UHPC outer cladding 113, and longitudinal reinforcement 115 is evenly distributed circumferentially within the CA-UHPC outer cladding 113. The shear studs 114 strengthen the bond between the two materials. "Longitudinal reinforcement 115" refers to the reinforcement distributed along the length of the hollow steel tube 111. The surface stirrups 116 and longitudinal reinforcement 115 enhance its ductility and, together with the inner steel tube, increase the bending bearing capacity of the main arch rib 1.

[0051] In this embodiment, the hangers above the bridge deck and below the arch ribs are arranged in parallel and crosswise fashion, while the arch columns 9 below the bridge deck and above the arch ribs are arranged in an oblique and crosswise fashion. The hangers and arch columns 9 are fixedly connected to the inside of the hollow steel tube 111. The inclined arrangement of the hangers and arch columns 9, which intersect at least twice, reduces the bending moment of the arch ribs and main beams. Because the main arch 1 structure of this bridge type primarily bears axial forces, its cross-sectional stress distribution is more uniform. This significantly reduces the cross-sectional dimensions of the arch ribs, reduces the weight of the structure, fully utilizes materials, and significantly improves structural efficiency and cost-effectiveness. To ensure that the continuous distribution of steel fibers within the CA-UHPC outer cladding 113 is not interrupted, the cable anchoring structure 112, column stiffening structure 119, cross brace 2 stiffening structure, as well as the on-site docking flange 117 and flange stiffening plates 120 and 118, which ensure precise alignment during installation of the prefabricated arch rib segments 11, are all disposed within the inner steel tube.

[0052] In this embodiment, the hollow steel tubes 111 of the main arch ribs are fixedly connected through a combination of flange butt joints and welding. The meshed slings are anchored within the hollow steel tubes 111. Stiffening plates 120 are installed at the junctions between the cross braces 2, the arch columns 9, and the hollow steel tubes 111. These stiffening plates 120 are located within the hollow steel tubes 111. The stiffening plates 120 at the junctions between the main arch 1, cross braces 2, and the arch columns 9 and the inner steel tubes, the flanges for on-site butt joints between the arch rib segments, and the cable-arch anchoring structure where the slings are anchored to the arch ribs are all located inside the inner steel tubes to ensure continuous distribution of the steel fibers in the CA-UHPC outer cladding 113. Furthermore, the concentrated forces transmitted to the arch ribs by these components are evenly distributed across the inner steel tubes through these stiffening structures. The inner hollow steel tube 111 in the arch rib is connected to the end pad 122 by welding, and a number of end stiffening plates 121 and 120 are evenly distributed around the ring to strengthen the connection between the two and achieve uniform force transmission.

[0053] In this embodiment, the longitudinal ends of the arch rib are fixed to the arch seat 3, and an inverted V-shaped side pier 5 is fixedly connected between the arch seat 3 and the bridge deck structure 4. The arch rib is relatively inclined inward to form a basket arch structure, and a vertical movable support is arranged between the bridge deck structure 4 and the abutment 6; the main arch 1 structural system adopts a double-hinged arch, and the arch hinge structure 10 adopts a spherical support structure; in the vertical layout, the intersection nodes between the arch rib and the bridge deck structure 4 are not connected; in the horizontal layout, the arch rib is arranged on both sides of the bridge deck structure 4; the arch columns 9 and the rigid hangers 8 near the intersection of the arch rib and the bridge deck structure 4 are hinged; the vertical structural stiffness of the entire bridge is increased by utilizing the anti-thrust stiffness of the inverted V-shaped side pier 5, and the side pier 5 is installed above the arch seat 3 and consolidated with the main beam; the arch rib is inclined inward to form a basket arch structure, which can significantly improve its lateral stability.

[0054] In this embodiment, the cross brace 2 is composed of four rods, one end of which intersects and is fixedly connected as a whole, and the other ends are obliquely connected to four different positions on the arch rib; "oblique connection" is relative to vertical connection. The cross brace 2 adopts a variant K-shaped brace, which can reduce the out-of-plane bending moment of the arch rib and provide relatively optimal lateral stiffness compared to conventional K-shaped, X-shaped and "M"-shaped cross braces 2. In addition, the cross brace 2 has fewer rods, which improves the permeability and aesthetic effect of the bridge. The intersection point of the four rods of the variant K-shaped brace structure is located at 1 / 4 of the longitudinal length of the cross brace 2 (from the shore to the mid-span).

[0055] In this embodiment, the arch rib is fixedly connected to the arch seat 3 via an arch hinge structure 10. The arch hinge structure 10 consists of an upper concave hemispherical structure 101, a lower convex hemispherical structure 102, and a sliding pair 103 located between the upper concave hemispherical structure 101 and the lower convex hemispherical structure 102. The upper concave hemispherical structure 101 and the lower convex hemispherical structure 102 are matched in a concave-convex manner and can slide relative to each other along the hemispherical surface. The lower convex hemispherical structure 102 is anchored to the arch seat 3 via a CA-UHPC pad 104. The arch hinge structure 10 consists of the upper concave hemispherical structure 101, the sliding pair 103, the lower convex hemispherical structure 102, and the CA-UHPC pad 104, thereby preventing lateral sliding. The sliding motion between two coordinated semi-circular spherical structures—the upper concave hemispherical structure 101 and the lower convex hemispherical structure 102, made of cast steel—and a sliding pair 103, made of a copper-based inlaid self-lubricating material, releases the rotation angle between the arch rib and the abutment 3. This releases the rotation angle and the arch foot bending moment in any direction, ensuring that any cross-section of the arch rib remains in a compressed state. Conventional pin-hinged or rocker-axis arch hinges can only rotate in a plane parallel to the arch rib and cannot release the out-of-plane bending moments of the arch foot caused by transverse wind, temperature, and live loads.

[0056] The arch axis pressure is transmitted between the upper concave hemispherical structure 101 and the end pad 122 in the arch hinge structure 10 through contact pressure, and an annular retaining bar is provided on the inner side of the end pad 122, and is clamped and fixed by a number of circumferentially evenly distributed connecting bolts 123. The inner hollow steel pipe 111 in the arch rib is connected to the end pad 122 by welding, and a number of end stiffening plates 121 and 120 are circumferentially evenly distributed to strengthen the connection between the two and achieve uniform force transmission. The arch axis force is transmitted between the lower convex hemispherical structure 102 in the arch hinge structure 10 and the CA-UHPC pad 104 through contact pressure, and is fixed by a number of circumferentially evenly distributed anchor bolts 124. The CA-UHPC pad 104 is provided between the arch hinge structure 10 and the arch seat 3 to diffuse the compressive stress.

[0057] In the above embodiment, the bridge deck structure 4 utilizes a steel-concrete composite beam structure to reduce deadweight, minimize internal forces in the arch ribs under constant load, and conserve steel. The bridge deck structure 4 utilizes a steel-concrete composite side-box beam, offering advantages such as superior mechanical properties, simple construction, and cost-effectiveness. The steel structure comprises a longitudinal and transverse beam system consisting of a side-box steel main beam 41, small longitudinal beams 42, and hollow transverse diaphragms 43. The concrete portion comprises a precast concrete bridge deck 45. Prior to bridge deck pavement construction, the precast concrete bridge deck 45 and the steel structure are connected via shear studs 114 and cast-in-place wet joints 46. Furthermore, longitudinal movable supports are provided at both ends of the bridge deck structure 4. The bridge deck structure 4 utilizes a cantilevered sidewalk 44, similar to a horizontal deflector, formed by combining a cantilever beam with a closed-section longitudinal beam on the outside of the wind nozzle. This significantly optimizes the main beam's aerodynamic shape and improves flow characteristics, thereby increasing the bridge deck structure's critical flutter wind speed and suppressing the amplitude of vortex-induced resonance.

[0058] In the above embodiment, the hangers are arranged at a constant inclination angle and at equal longitudinal spacing, effectively reducing fatigue issues in the anchor structure. The arch columns 9 and rigid hangers 8 are constructed of steel pipes, while the flexible hangers can be constructed of high-strength steel wire or carbon fiber cables. For arch columns 9 and all rigid hangers 8, which have relatively small slenderness, both ends are connected to the main beam or arch rib via pin hinges 91 to relieve additional bending moments.

[0059] In the above embodiment, the arch seat 3 is composed of an enlarged foundation 31, inclined piles 33 and vertical piles 32 to resist the huge thrust of the arch rib, and has the advantages of clear force path, small excavation volume and small environmental impact.

[0060] The construction method of the mid-through mesh hanger arch bridge of this embodiment includes the following steps:

[0061] (1) The prefabricated arch rib segments 11 are erected by using an arch erection crane 203. Before the arch ribs 1 are closed, temporary inclined cables 202 assist in bearing the force of the main arch ribs 1. After the main arch structure is formed, the temporary inclined cables 202 are gradually removed.

[0062] (2) The arch columns 9, rigid hangers 8, mesh suspenders 7 and bridge deck structure 4 are constructed in sections from the shore side to the mid-span;

[0063] (3) Install the precast concrete bridge deck 45, then tension the mesh suspenders 7, adjust the overall line shape of the bridge deck structure 4, cast the bridge deck cast-in-situ wet joints 46, symmetrically dismantle the temporary diagonal stay cables 202 and temporary towers 201, and complete the construction of the main bridge structure;

[0064] The construction method of the arch rib comprises the following steps:

[0065] S1. After the prefabricated arch rib segments 11 and the inner hollow steel tube 111 are manufactured in the factory, the CA-UHPC outer layer 113 is cast and steam cured.

[0066] S2. Use a transport barge 205 to transport the prefabricated arch rib segments 11 from the factory to the bridge site and use an arch crane 203 to hoist them;

[0067] S3, using the on-site butt flange 117 provided at the end of the inner steel pipe 111 in the prefabricated arch rib segment 11 to achieve accurate alignment of the prefabricated arch rib segment 11 to be installed, and performing on-site butt welding of the inner steel pipe 111 after the installation line meets the requirements;

[0068] S4. After the inner steel pipe 111 is welded and passed the flaw detection, the CA-UHPC cast-in-place joint 12 is cast on site and steam cured on site.

[0069] During the installation of the precast arch rib segments 11, an arch crane 203 is used to lock the completed main arch ribs 1 and the precast arch rib segments 11 to be installed together. This ensures that the cast-in-place CA-UHPC joints 12 do not experience tensile or compressive deformation during solidification, which could lead to cracking. The CA-UHPC joints 12's external formwork system, vacuum infusion system (to ensure tight CA-UHPC wet joints), and on-site steam curing system are all included in the arch crane 203.

[0070] See also Figure 16 The construction method of the above-mentioned half-through mesh hanger arch bridge includes the following steps:

[0071] Step a. Excavating vertical piles 32, diagonal piles 33 and the expanded foundation 31 of the arch seat 3, and then pouring concrete for the arch seat 3 and constructing temporary anchors 204;

[0072] Step b casting the CA-UHPC cushion layer 104 in the arch hinge structure 10, and then installing the lower convex hemispherical structure 102, the sliding cap 103 and the concave hemispherical structure 101;

[0073] Step c. Using a floating crane to install the starting section of the prefabricated arch rib segment 11;

[0074] Step d. Installing the arch crane 203 on the main arch rib 1 has completed construction;

[0075] Step e. Using the transport barge 205 to transport the prefabricated arch rib segments 11 to the bridge site, the prefabricated arch rib segments 11 are installed segment by segment by the arch crane 203, while installing and tensioning the temporary diagonal cable 202;

[0076] Step f repeats step e, continues symmetrically, synchronously installs the prefabricated arch rib segment 11, in the process chooses the time to adjust the line shape of the main arch rib 1 as needed;

[0077] Step g. Before closing the main arch, use temporary diagonal cables 202 to align the elevations of the closing openings of the main arch ribs 1 at both ends. Then, use the arch crane 203 to temporarily lock the main arch ribs 1 on both sides. Then, hoist the arch rib closing section. Next, accurately align the main arch ribs 1 and the arch rib closing section on both sides. Then, perform on-site butt welding of the inner steel pipes 111. After welding is completed and the flaw detection is passed, cast-in-place CA-UHPC joints 12 are cast on-site and steam cured on-site, thus completing the closing of the main arch structure.

[0078] Step h. Construct the abutments 6 on both sides, install the inverted V-shaped piers 5, and use the beam crane 206 to hoist the arch columns 9 and the steel structure parts of the bridge deck structure 4 (i.e., the side box steel main beams 41, small longitudinal beams 42 and hollow cross beams 43) from the shore side to the mid-span.

[0079] Step i. Install the rigid hangers 8 and the mesh suspenders 7 one by one from the shore side toward the mid-span direction, while continuing to use the beam crane 206 to install the steel beam portion of the bridge deck structure 4 until it is closed.

[0080] Step j. Install the precast concrete bridge deck 45 piece by piece synchronously and symmetrically from the shore side toward the mid-span direction, then tension the mesh suspenders 7 and adjust the overall line shape of the bridge deck structure 4.

[0081] Step k. Cast the cast-in-place wet joints 46. After the concrete reaches the designed strength, remove the temporary cable stays 202 and the temporary towers 201 one by one and symmetrically, completing the construction of the main structure of the bridge.

[0082] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not limiting. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the purpose and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A mid-through lattice-type hanger arch bridge, characterized by: It includes curved arch ribs located on both sides of the bridge deck structure, and mesh hangers and arch columns connecting the arch ribs and the bridge deck structure. Multiple cross braces are arranged between the arch ribs. The arch ribs are composed of hollow steel tubes connected together. The outer surface of the hollow steel tubes is covered with a layer of CA-UHPC outer layer. The hangers above the bridge deck and below the arch ribs are parallel and cross each other at least twice. The arch columns below the bridge deck and above the arch ribs are distributed obliquely and crosswise. The hangers and arch columns are connected to the hollow steel tubes and connected by reinforcing nodes constructed on the inner side.

2. The mid-through reticular hanger arch bridge according to claim 1, characterized in that: Shear nails are radially arranged at the interface between the hollow steel pipe and the CA-UHPC outer cladding. The shear nails are evenly distributed along the circumference of the CA-UHPC outer cladding. Stirrups are provided on the outer surface of the CA-UHPC outer cladding, and longitudinal steel bars are evenly distributed circumferentially inside the CA-UHPC outer cladding.

3. The mid-through reticular hanger arch bridge according to claim 1, characterized in that: The hollow steel pipes of the arch ribs are fixedly connected by flange butt welding, the mesh hangers are anchored in the hollow steel pipes, and the connection nodes of the cross braces, arch columns and hollow steel pipes are all provided with stiffening plates, which are located in the hollow steel pipes.

4. The mid-through reticular hanger arch bridge according to claim 3, characterized in that: The longitudinal ends of the arch rib are fixed to the arch seat, and an inverted V-shaped side pier is fixedly connected between the arch seat and the bridge deck structure. The arch rib is relatively inclined inward to form a basket arch structure.

5. The mid-through reticular hanger arch bridge according to claim 1 is characterized in that: The cross brace is composed of four rods, one end of which intersects and is fixedly connected as a whole, and the other ends are obliquely connected to four different positions on the arch rib.

6. The mid-through reticular hanger arch bridge according to claim 5, characterized in that: The intersection and fixing point of the four rods is located at 1 / 4 of the longitudinal length of the cross brace.

7. The mid-through reticular hanger arch bridge according to claim 1, characterized in that: The arch rib is connected to the arch seat through an arch hinge structure to form a double-hinge arch structure system. The arch hinge structure consists of an upper concave hemispherical structure, a lower convex hemispherical structure, and a sliding pair located between the upper concave hemispherical structure and the lower convex hemispherical structure. The upper concave hemispherical structure and the lower convex hemispherical structure are matched with each other and can slide relative to each other along the hemispherical surface. The lower convex hemispherical structure diffuses and transmits force to the arch seat through a CA-UHPC pad.

8. The construction method of a half-through lattice-type hanger arch bridge according to claim 1, characterized in that: The following steps are involved: (1) Prefabricated arch rib segments are erected using an arch crane. Before the arch ribs are closed, temporary inclined cables are used to assist the main arch ribs in bearing stress. After the main arch structure is formed, the temporary inclined cables are gradually removed. (2) The arch columns, rigid hangers, mesh cables and bridge deck structures are constructed in sections from the shore to the mid-span; (3) Install the precast concrete bridge deck, then tension the mesh cables, adjust the overall line shape of the bridge deck structure, cast the bridge deck in-situ wet joints, symmetrically remove the temporary cable stays and temporary towers, and complete the construction of the main bridge structure.

9. The construction method of a half-through lattice hanger arch bridge according to claim 8, characterized in that: The construction method of the arch rib comprises the following steps: S1. Prefabricated arch rib segments are manufactured in the factory. After the inner hollow steel tubes are manufactured, the CA-UHPC outer layer is poured and steam cured. S2. Use a transport barge to transport the prefabricated arch rib segments from the factory to the bridge site and hoist them using an arch crane; S3. The use of on-site butt flanges provided in the inner steel pipe ends of the prefabricated arch rib segments is achieved by accurately positioning the prefabricated arch rib segments to be installed, and the inner steel pipe is butt-welded on-site after the installation line meets the requirements; S4. After the inner steel pipe welding is completed and the flaw detection is qualified, the CA-UHPC cast-in-place joint is cast on site and steam cured on site.

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