Fabricated steel tube inner core externally wrapped UHPC arch rib connecting joint, arch bridge and method

Abstract

The invention discloses an assembly type steel pipe inner core wrapped UHPC arch rib connecting node, an arch bridge and a method, the assembly type steel pipe inner core wrapped UHPC arch rib connecting node comprises hollow steel pipes, the hollow steel pipes are arranged in a sectional mode, the outer diameter of each section of hollow steel pipe is wrapped with a prefabricated UHPC outer wrapping layer, and field butt flanges are arranged at the connecting ends of the adjacent hollow steel pipes; the adjacent hollow steel pipes are connected through on-site butt joint flanges and connecting bolts, a plurality of steel pipe shear nails and flange stiffening steel plates are arranged on the outer diameters of the adjacent hollow steel pipes close to the connecting ends, the adjacent hollow steel pipes are sleeved with steel plates, steel plate shear nails are arranged on the inner walls of the steel plates, and cast-in-place UHPC outer wrapping layers are arranged at the connecting ends of the adjacent hollow steel pipes. The construction method has the advantages that the segment hoisting weight is low, the apparent durability is good, the construction measure investment cost is low, rapid construction of the high-prefabricated arch rib segments can be achieved, the construction quality can be guaranteed, the construction method is simplified, and the construction period is shortened.

Description

Technical Field

[0001] The present invention relates to the technical field of bridge construction, and in particular to an assembled steel pipe inner core outer-wrapped UHPC arch rib connection node, an arch bridge and a method. Background Art

[0002] In mountainous canyon areas, compared with suspension bridges and cable-stayed bridges of the same span, large-span arch bridges are highly competitive due to their outstanding advantages in economy, durability, construction period, and wind and earthquake resistance.

[0003] At present, steel tube concrete arch bridges, rigid skeleton concrete arch bridges, and steel truss arch bridges are the main forms of long-span arch bridges, but there are still certain bottlenecks in the further breakthrough of span. With the increase of span, the deadweight of steel tube concrete arch and rigid skeleton concrete arch bridge gradually dominates. According to the conventional design, the construction difficulty and construction measures cost of the cable-stayed buckle-hanging cantilever assembly system increase sharply with the increase of span, and the economic efficiency becomes worse; on the other hand, despite the remarkable progress in the preparation and vacuum infusion process of high-flow, internally cured and shrinkage-free high-strength concrete in steel tubes, defects such as local debonding and degassing of concrete in the tube still exist, which brings confusion to structural design and safe operation and maintenance. The spanning capacity of steel box or steel truss arch bridges is greater than that of concrete arch bridges, but with the increase of span, the overall and local buckling stability problems of the structure begin to emerge. If the structural size is increased, it will bring about the problem of difficulty in welding thick steel plates. There are also other problems such as prominent steel node fatigue problems, high structural cost and high later operation and maintenance costs. In addition, both steel arch bridges and steel tube concrete arch bridges have a large number of exposed steel structures, and the full life maintenance cost cannot be underestimated.

[0004] At present, the connection method of the main arch rib of steel tube concrete and rigid skeleton concrete arch bridge is generally welded connection method, which is as follows: the arch rib steel pipe is bolted and fixed with an external flange, and the external flange is cut after welding the rest of the parts and then the original flange part is welded. Cutting the external flange will cause stress redistribution, resulting in problems with the stress stability of the arch bridge. Cutting and welding will also extend the construction period. At the same time, in order to ensure the quality of concrete in the pipe, high requirements are placed on the welds of the connecting steel pipes. Since the construction conditions are high-altitude operations, the construction of the existing welding method has certain safety risks. With the increase of the span of the arch bridge and the increase of the construction height, the diameter of the arch rib steel pipe increases. Due to the weight of the large steel pipe itself and the requirement of vacuum pouring concrete in the pipe, the arch rib steel pipe node weld connection is difficult to complete at one time, and multi-section batch welding will increase the difficulty of construction, which is easy to cause uneven stress distribution, stress redistribution and uneven weld quality at the node, making it difficult to achieve the welding quality and construction effect that meet the requirements. Arch rib connection technology is still a difficult problem to be solved for large-span arch bridges.

[0005] In terms of arch rib manufacturing, installation and construction technology, there are mainly construction technologies such as cable-stayed buckle-hanging cantilevered splicing and cantilevered casting, rigid skeleton cantilevered splicing and outsourcing concrete pouring, reinforced concrete arch bridge rotation and steel arch bridge large segment lifting. Among them, steel arch bridges mainly adopt construction methods such as cable-stayed buckle-hanging cantilevered splicing and large segment lifting; concrete arch bridges mainly adopt construction methods such as cable-stayed buckle-hanging cantilevered splicing and rigid skeleton; steel tube concrete arch bridges mainly adopt cable-stayed buckle-hanging cantilevered splicing, and a small part adopts rotation construction method. Cable-stayed buckle-hanging cantilevered splicing is still the main construction method for large-span arch bridges. With the increase of the span of the arch bridge, the number and weight of the main arch segments have increased significantly, and the problems of dual nonlinear stability, construction monitoring and state control faced in the whole construction process have gradually become prominent.

[0006] In summary, there is at least one of the following technical problems:

[0007] The construction difficulty and construction cost of the cantilever assembly system of the inclined stay buckle increase sharply with the increase of span, and the economic efficiency becomes worse;

[0008] Although the preparation and vacuum infusion technology of high-flow, internally cured, shrinkage-free high-strength concrete in steel pipes has made remarkable progress, defects such as local debonding and voiding of concrete in pipes still exist, which brings confusion to structural design and safe operation and maintenance;

[0009] The spanning capacity of steel box or steel truss arch bridges is greater than that of concrete arch bridges. However, as the span increases, the overall and local buckling stability problems of the structure begin to become prominent. If the structural size is increased, it will be difficult to weld thick steel plates. There are also other problems such as prominent steel node fatigue problems, high structural costs and high subsequent operation and maintenance costs.

[0010] Due to the weight of the large steel pipe itself and the requirement of vacuum pouring concrete inside the pipe, it is difficult to complete the weld connection of the arch rib steel pipe node in one go, and welding in batches of multiple sections will increase the difficulty of construction, which is easy to cause problems such as uneven stress distribution at the node, stress redistribution and uneven weld quality. It is difficult to achieve the welding quality and construction effect that meet the requirements. The arch rib connection technology is still a difficult problem that needs to be solved urgently for long-span arch bridges.

[0011] Both steel arch bridges and steel tube concrete arch bridges have a large amount of exposed steel structure, and the maintenance cost over the entire life cycle cannot be underestimated;

[0012] Cable-stayed, buckled, and suspended construction is still the main construction method for large-span arch bridges. With the increase in the span of the arch bridge, the number and weight of the main arch segments increase significantly, and the problems of dual nonlinear stability, construction monitoring, and state control faced in the entire construction process gradually become prominent. Summary of the invention

[0013] The main purpose of the present invention is to provide a prefabricated steel pipe inner core outer-wrapped UHPC arch rib connection node, arch bridge and method to solve at least one technical problem in the background technology.

[0014] In order to achieve the above-mentioned purpose, according to one aspect of the present invention, there is provided an assembled steel pipe inner core outer covering UHPC arch rib connection node, comprising a hollow steel pipe, the hollow steel pipe is arranged in sections, the outer diameter of each hollow steel pipe section is covered with a prefabricated UHPC outer covering, an on-site docking flange is provided at the connecting end of the adjacent hollow steel pipes, the adjacent hollow steel pipes are connected by the on-site docking flange and connecting bolts, a plurality of steel pipe shear nails and flange stiffening steel plates are provided at the outer diameter of the adjacent hollow steel pipes near the connecting end, a steel plate is sleeved at the adjacent hollow steel pipes, a steel plate shear nail is provided on the inner wall of the steel plate, and a cast-in-place UHPC outer covering is provided at the connecting end of the adjacent hollow steel pipes.

[0015] Preferably, at the connection of the unit tube arch rib segments, the hollow steel pipe adopts an inwardly inclined structure from the prefabricated UHPC outer cladding to the cast-in-place UHPC outer cladding, and steel pipe shear nails are arranged in the inwardly inclined structure section, and the steel pipe shear nails are uniformly welded on the steel pipe in the circumferential direction.

[0016] Preferably, the steel plate is arranged from the prefabricated UHPC outer cladding section to the cast-in-place UHPC outer cladding section, steel plate shear nails are uniformly welded on the steel plate, and the steel plate shear nails and the steel pipe shear nails on the steel pipe are staggered.

[0017] Preferably, the hollow steel pipe adopts a cylindrical and conical combined structure, and the hollow steel pipe is used as a casting template for the prefabricated UHPC outer cladding and the on-site UHPC outer cladding.

[0018] Preferably, the length of the steel plate in the prefabricated UHPC outer cladding section is twice its length in the cast-in-place UHPC outer cladding section, and the steel plate is aligned with the boundary of the shear studs.

[0019] According to another aspect of the present invention, there is provided an assembled steel tube inner core outer-wrapped UHPC arch rib connected arch bridge, comprising:

[0020] reinforced concrete abutments;

[0021] A single circular tube arch rib, both ends of which are connected to reinforced concrete arch seats;

[0022] The arch columns include a plurality of arch columns, and the lower ends of the arch columns are connected to the single circular tube arch rib;

[0023] A cap beam, the cap beam being arranged at the upper end of the single circular tube column;

[0024] A bridge deck beam, wherein the bridge deck beam is arranged at the upper end of the cap beam;

[0025] Arch rib wind bracing, wherein the arch rib wind bracing is arranged between the single circular tube arch ribs;

[0026] Prestressed steel bars for bridge deck beams, wherein the prestressed steel bars for bridge deck beams are arranged in the bridge deck beams;

[0027] UHPC prefabricated panels, wherein the UHPC prefabricated panels are arranged between adjacent bridge deck beams;

[0028] a ground anchor disposed on the ground; and

[0029] A tower, wherein the tower is arranged vertically;

[0030] A cable, wherein both ends of the cable are respectively connected to the tower;

[0031] A cable, one end of which is connected to the tower frame, and the other end of which is connected to the single circular tube arch rib.

[0032] Preferably, the arch columns and the bridge deck beams both adopt prefabricated assembled structures, the columns adopt assembled UHPC thin-walled rectangular columns, and the bridge deck beams adopt assembled pre-tensioned prestressed UHPC beams.

[0033] Preferably, a cable is installed at the connection of each single-circular tube arch rib segment, and the cable provides a hanging tension at the connection of the single-circular tube arch rib segment.

[0034] Preferably, the buckle cable is also connected to a ground anchor.

[0035] According to another aspect of the present invention, there is provided a method for using an assembled steel pipe inner core and outer UHPC arch rib connection node, comprising:

[0036] Step 1: The hollow steel pipe is manufactured and processed in the steel structure processing plant, and after the on-site docking flange, steel plate and shear nails are welded, it is transported to the concrete prefabrication plant to cast the UHPC outer layer. Moisture curing and steam curing are carried out according to the design and specification requirements to form an assembled steel pipe inner core and UHPC outer layer arch rib segment;

[0037] Step 2: After the construction of the arch seat is completed, the tower and anchor of the inclined buckle hanging hoisting system are constructed, and the system is installed and debugged to test the reliability of the hoisting system;

[0038] Step 3: transport the prefabricated arch rib segments in the factory to the bridge construction site by transport barges, and hoist the arch rib segments;

[0039] Step 4: After adjusting the spatial posture of the single circular arch rib to the corresponding position and angle by tensioning the inclined cable, the inner steel pipe end is used to accurately dock the on-site docking flange, and the flange is bolted after the linear shape of the single circular arch rib is controlled;

[0040] Step 5: After the single circular tube arch rib segment installation inspection is passed, cast-in-place UHPC outer cladding.

[0041] The application of the technical solution of the present invention has the following technical effects:

[0042] The steel pipe is used as the inner mold and UHPC is wrapped on the outside to form a new structure of a composite arch bridge. The steel pipe can be used as a UHPC casting template. The main arch ribs of the arch bridge are mainly under pressure. UHPC has excellent compressive resistance. Matching UHPC with weather-resistant high-strength steel to bear the force together can save materials and reduce the deadweight of the structure, thereby improving the spanning capacity of the bridge.

[0043] Due to the superior crack resistance and durability of UHPC, the corrosion of internal steel can be avoided to the greatest extent, the durability of the bridge structure can be improved, its service life can be extended, and the maintenance and repair costs during operation can be reduced.

[0044] The cross-section of the steel tube core wrapped with UHPC arch ribs is formed in one step, and the structural force is clear. Although the dead weight of a single segment is large and there are many hoisting segments, it eliminates the tedious work of pouring concrete inside the traditional steel tube concrete arch bridge and wrapping concrete on the rigid skeleton concrete arch, which can speed up the construction process.

[0045] In addition to the highly prefabricated and assembled structure of the arch rib segments, the arch columns and bridge deck beams also use prefabricated and assembled UHPC structures, realizing the highly prefabricated, assembled and precise aerial installation construction of the lightweight arch ribs and superstructure, and achieving high durability, long life and low maintenance for the entire bridge.

[0046] Compared with the traditional arch rib segment welding method using dry joints, the arch rib segment connection nodes of the present invention use a combination of flange bolting and UHPC wet joints, which can eliminate the workload of high-altitude welding and reduce the construction difficulty of high-altitude operations; and the concrete thickness is locally thickened at the joints, stiffening steel plates are added, and shear nails are welded to improve the stability and integrity of the connection nodes. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] The drawings constituting a part of the present application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0048] Figure 1 A schematic diagram of the general arrangement structure of a double circular steel tube inner core wrapped with UHPC arch bridge configuration with an assembled steel tube inner core wrapped with UHPC arch rib connection node according to the present invention is shown;

[0049] Figure 2 Shows Figure 1 A top view of the general layout of the double circular steel tube inner core wrapped with UHPC arch bridge configuration with prefabricated steel tube inner core wrapped with UHPC arch rib connection nodes;

[0050] Figure 3 Shows Figure 1 The three-dimensional perspective structural view of the double circular steel tube inner core wrapped with UHPC arch bridge configuration with prefabricated steel tube inner core wrapped with UHPC arch rib connection nodes;

[0051] Figure 4 Shows Figure 1 The first partial enlarged view of the double circular steel tube inner core wrapped with UHPC arch bridge configuration with prefabricated steel tube inner core wrapped with UHPC arch rib connection nodes;

[0052] Figure 5 Shows Figure 1 The second partial enlarged view of the double circular steel tube inner core wrapped with UHPC arch bridge configuration with prefabricated steel tube inner core wrapped with UHPC arch rib connection nodes;

[0053] Figure 6 Shows Figure 1 The third partial enlarged view of the double circular steel tube inner core wrapped with UHPC arch bridge configuration with prefabricated steel tube inner core wrapped with UHPC arch rib connection nodes;

[0054] Figure 7 Shows Figure 1 The fourth partial enlarged view of the double circular steel tube inner core wrapped with UHPC arch bridge configuration with prefabricated steel tube inner core wrapped with UHPC arch rib connection nodes;

[0055] Figure 8 Shows Figure 1 The general layout front view of the double-four-limb steel tube inner core wrapped with UHPC arch bridge configuration with prefabricated steel tube inner core wrapped with UHPC arch rib connection nodes;

[0056] Fig. 9 Shows Figure 1 A top view of the general layout of the double-four-limb steel tube core wrapped with UHPC arch bridge configuration with prefabricated steel tube core wrapped with UHPC arch rib connection nodes;

[0057] Fig.10 Shows Figure 1 A three-dimensional perspective view of the double-four-limb steel tube core wrapped with UHPC arch bridge configuration with prefabricated steel tube core wrapped with UHPC arch rib connection nodes;

[0058] Fig.11 Shows Figure 1 The first partial enlarged view of the double-four-limb steel tube inner core wrapped with UHPC arch bridge configuration with prefabricated steel tube inner core wrapped with UHPC arch rib connection nodes;

[0059] Fig.12 Shows Figure 1 The second partial enlarged view of the double-four-limb steel tube inner core wrapped with UHPC arch bridge configuration with prefabricated steel tube inner core wrapped with UHPC arch rib connection nodes;

[0060] Fig.13 Shows Figure 1The third partial enlarged view of the double-four-limb steel tube inner core wrapped with UHPC arch bridge configuration with prefabricated steel tube inner core wrapped with UHPC arch rib connection nodes;

[0061] Fig.14 Shows Figure 1 The fourth partial enlarged view of the double-four-limb steel tube inner core wrapped with UHPC arch bridge configuration with prefabricated steel tube inner core wrapped with UHPC arch rib connection nodes;

[0062] Fig.15 Shows Figure 1 The cross-sectional view of the steel tube inner core wrapped with UHPC arch rib structure of the prefabricated steel tube inner core wrapped with UHPC arch rib connection node;

[0063] Fig.16 Shows Figure 1 The butt joint view of the arch rib connection node based on the external flange connection of the fabricated steel tube inner core and UHPC arch rib connection node;

[0064] Fig.17 Shows Figure 1 The structural elevation view of the arch rib connection node based on the external flange connection of the fabricated steel tube inner core and the UHPC arch rib connection node;

[0065] Fig.18 Shows Figure 1 The structural plan view of the arch rib connection node based on the external flange connection of the fabricated steel tube inner core and UHPC arch rib connection node;

[0066] Fig.19 Shows Figure 1 A partial enlarged view of the arch rib node of the prefabricated steel tube inner core wrapped with UHPC arch rib connection node based on the external flange connection;

[0067] Fig. 20 Shows Figure 1 The structural elevation of the arch rib node based on the inner flange connection of the fabricated steel tube inner core and the UHPC arch rib connection node;

[0068] Fig.21 Shows Figure 1 The structural plan of the arch rib node with inner flange connection of the fabricated steel tube inner core and UHPC outer rib connection node;

[0069] Fig. 22 Shows Figure 1 A partial enlarged view of the arch rib node of the prefabricated steel tube inner core wrapped with UHPC arch rib connection node based on the inner flange connection;

[0070] Fig.23 Shows Figure 1Schematic diagram of the arch rib connection section of the steel tube core wrapped with UHPC arch bridge with prefabricated steel tube core wrapped with UHPC arch rib connection node;

[0071] Fig.24 Shows Figure 1 Schematic diagram of the structural layout of the UHPC arch rib inclined stay buckle hanging hoisting system of the steel tube core wrapped UHPC arch bridge arch rib connection node;

[0072] Fig.25 Shows Figure 1 Schematic diagram of the arch rib connection section of the double-four-limb steel tube inner core wrapped with UHPC arch bridge with prefabricated steel tube inner core wrapped with UHPC arch rib connection node;

[0073] Fig.26 Shows Figure 1 Schematic diagram of the structural layout of the double-four-leg steel tube inner core wrapped with UHPC arch bridge arch rib inclined buckle hanging hoisting system with assembled steel tube inner core wrapped with UHPC arch rib connection nodes.

[0074] The above drawings include the following reference numerals:

[0075] Single circular tube arch rib 1; arch rib wind bracing 2; arch upper column 3; column cross brace 4; cap beam 5; bridge deck beam 6; reinforced concrete arch seat 7; prestressed steel bars for bridge deck beam 8; UHPC precast slab 9; four-limb truss steel tube inner core with UHPC arch rib 10; ground anchor 31; tower 32; cable 33; cable 34; transport barge 41; hollow steel pipe 111; precast UHPC outer cladding 112; on-site docking flange 113; flange stiffening steel plate 114; connecting bolts 115; steel pipe shear nails 116; steel plate 117; steel plate shear nails 118; cast-in-place UHPC outer cladding 119; UHPC outer cladding 211. DETAILED DESCRIPTION

[0076] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0077] Lightweight structural design is one of the effective solutions to the problems of large-span arch bridges, such as excessive deadweight, difficult construction, and high cost of measures. Lightweight structural design depends largely on the progress of material science and new structural design. Using UHPC to replace ordinary concrete materials and reasonably matching it with conveniently connected steel structures to achieve lightweight arch bridge design is expected to make progress in increasing the reasonable span of the structure, reducing the deadweight of the structure, making full use of mature cable-stayed buckle-hanging cantilever construction technology, and reducing the cost of the entire life cycle, so as to achieve the iterative development of the structural configuration of large-span arch bridges. Ultra-high Performance Concrete (UHPC) refers to a high-toughness cement-based composite material with ultra-high mechanical properties and ultra-high durability made of raw materials such as cement, mineral admixtures, aggregates, fibers, admixtures and water. The compressive strength of UHPC can reach over 120MPa. When used in concrete arch bridges, it can give full play to the material's high compressive resistance, reduce material usage, and achieve lightweighting of large-span arch bridges. At the same time, UHPC has excellent durability. When used in concrete arch bridges, it can achieve low maintenance or even maintenance-free, inheriting the low operation and maintenance advantage of ordinary concrete arch bridges.

[0078] like Figures 1 to 26 As shown, an embodiment of the present invention provides an assembled steel pipe inner core outer UHPC arch rib connection node, comprising: a hollow steel pipe 111, the hollow steel pipe 111 is arranged in sections, the outer diameter of each section of the hollow steel pipe 111 is covered with a prefabricated UHPC outer cladding 112, an on-site docking flange 113 is provided at the connection end of the adjacent hollow steel pipes 111, the adjacent hollow steel pipes 111 are connected by the on-site docking flange 113 and the connecting bolts 115, a plurality of steel pipe shear nails 116 and flange stiffening steel plates 114 are provided on the outer diameter of the adjacent hollow steel pipes 111 near the connection end, a steel plate 117 is sleeved at the adjacent hollow steel pipes 111, and a steel plate shear nail 118 is provided on the inner wall of the steel plate 117, and a cast-in-place UHPC outer cladding 119 is provided at the connection end of the adjacent hollow steel pipes 111.

[0079] In this embodiment, at the connection of the unit tube arch rib segment, the hollow steel pipe 111 adopts an inner inclined structure from the prefabricated UHPC outer cladding 112 to the cast-in-place UHPC outer cladding 119, and a steel pipe shear nail 116 is arranged in the inner inclined structure section, and the steel pipe shear nail 116 is uniformly welded on the steel pipe in the circumferential direction. The steel plate 117 is arranged from the prefabricated UHPC outer cladding 112 section to the cast-in-place UHPC outer cladding 119 section, and the steel plate shear nail 118 is uniformly welded on the steel plate 117, and the steel plate shear nail 118 is staggered with the steel pipe shear nail 116 on the steel pipe. The hollow steel pipe 111 adopts a cylindrical and conical combined structure, and the hollow steel pipe 111 is used as a casting template for the prefabricated UHPC outer cladding 112 and the on-site UHPC outer cladding 211. The length of the steel plate 117 in the precast UHPC outer cladding 112 section is twice as long as its length in the cast-in-place UHPC outer cladding 119 section, and the steel plate 117 is aligned with the boundary of the shear studs.

[0080] In this embodiment, the arch rib node structure is designed as an inner and outer flange and steel pipe externally welded bolts and cast-in-place UHPC wet joint; it includes a hollow steel pipe as an inner core and UHPC wrapped with a steel pipe on the outside; the arch rib node is a node located between two sections of prefabricated steel pipes and UHPC arch rib segments based on flange connection, and the arch rib node includes: the steel pipe of the main arch rib segment is inwardly inclined at the connection, the UHPC layer wrapped in the inwardly inclined section of the steel pipe is cast-in-place, the hollow steel pipes 111 are connected by flanges and bolted, stiffening rib steel plates 117 welded to the steel pipes are arranged at both ends of the flange, and radial shear nails are arranged at the interface between the arch rib segment steel pipe and the UHPC outer layer 211 on both sides of the flange, and the shear nails are arranged along the UHPC outer layer 211. 1 Circumferentially uniform arrangement; The steel pipe outwrapped UHPC arch rib node based on flange connection can be connected by external flange or internal flange. The external flange is located at the steel pipe and the cast-in-place outwrapped UHPC layer, and the internal flange is located at the hollow inside the steel pipe. The advantage of the external flange over the internal flange is that the construction is more convenient and easier to operate manually. The UHPC wrapped flange and stiffening steel plate 117 improve the integrity of the connection node; the advantage of the internal flange is that it can not only realize the bolting of the internal flange, but also realize the welding of the outside of the steel pipe. The disadvantage is that if the diameter of the steel pipe is small, it is not easy for workers to operate inside. In the joint section, workers cannot reach the inside of the steel pipe for operation; At the connection of the main arch rib segment, the flange is welded to the steel pipe and bolted, and then the cast-in-place UHPC Compared with the connection method using welding, the structural form greatly improves the reliability and stability of the connection while reducing the construction difficulty; flange stiffening steel plates 114 are arranged on both sides of the flange joint to reduce the adverse effects of the space distortion generated by the arch rib when bearing on the arch rib node connection, thereby improving the stability and bearing capacity of the structure; at the connection of the main arch rib segment, the hollow steel pipe 111 is tilted inward from the prefabricated UHPC section to the cast-in-place UHPC section to increase the thickness of the UHPC section at the flange joint, and shear nails are arranged in the inward section and welded uniformly on the steel pipe in the circumferential direction, which can increase the wrapping force and bonding force between the hollow steel pipe 111 and the UHPC outer cladding 211 while enhancing the shear resistance of the connection section, thereby improving the connection performance. The mechanical properties and bearing capacity of the arch ribs are improved; at the connection of the main arch rib segments, a steel plate 117 can be set from the precast UHPC segment to the cast-in-place UHPC segment, and shear nails are evenly welded on the steel plate 117, which are staggered with the shear nails on the steel tube. While enhancing the shear resistance of the connection, the continuity of the precast concrete segment and the cast-in-place concrete segment is improved, thereby improving the overall performance of the structure; the arch rib adopts a cantilever fully prefabricated assembly construction, which eliminates the in-tube concrete pouring of the steel tube concrete arch bridge and the out-wrapped concrete pouring of the rigid skeleton concrete arch bridge, and combines the advantages of the assembled rapid construction of the steel tube concrete arch bridge and the good durability of the out-wrapped concrete arch bridge, which has obvious advantages in terms of structural lightweight, assembly rate, durability, construction period, economy, etc.

[0081] Example 2

[0082] Another aspect of the present invention provides an arch bridge with an assembled steel pipe inner core and UHPC arch ribs, comprising:

[0083] Reinforced concrete arch seat 7;

[0084] A single circular tube arch rib 1, wherein both ends of the single circular tube arch rib 1 are respectively connected to a reinforced concrete arch seat 7;

[0085] The arch columns 3 include a plurality of arch columns, and the lower ends of the arch columns 3 are connected to the single circular tube arch rib 1;

[0086] A cap beam 5, wherein the cap beam 5 is arranged at the upper end of the single circular tube column;

[0087] A bridge deck beam 6, wherein the bridge deck beam 6 is arranged at the upper end of the cap beam 5;

[0088] Arch rib wind bracing 2, wherein the arch rib wind bracing 2 is arranged between the single circular tube arch ribs 1;

[0089] Prestressed steel bars 8 for bridge deck beams, the prestressed steel bars 8 for bridge deck beams are arranged in the bridge deck beams 6;

[0090] UHPC prefabricated panels 9, wherein the UHPC prefabricated panels 9 are arranged between adjacent bridge deck beams 6;

[0091] A ground anchor 31, wherein the ground anchor 31 is disposed on the ground; and

[0092] A tower 32, wherein the tower 32 is vertically arranged;

[0093] A cable 33, wherein both ends of the cable 33 are respectively connected to the tower 32;

[0094] A cable 34 , one end of which is connected to the tower 32 , and the other end of which is connected to the single circular tube arch rib 1 .

[0095] In this embodiment, the arch columns 3 and the bridge deck beam 6 are both prefabricated and assembled structures. The columns are assembled UHPC thin-walled rectangular columns, and column cross braces 4 are provided on the columns. The bridge deck beam 6 is assembled pre-tensioned prestressed UHPC beams. A cable 34 is suspended at the connection of each single-circular arch rib 1 segment, and the cable 34 provides the suspension tension at the connection of the single-circular arch rib 1 segment. The cable 34 is also connected to the anchor 31.

[0096] In this embodiment, the steel tube core is wrapped with UHPC to form a steel-UHPC composite arch rib. For different spans and different structural arrangements, a single steel tube core is wrapped with UHPC arch rib or a four-limb steel tube core is wrapped with UHPC arch rib. If transportation is convenient, it is feasible to adopt a simple double single tube arch rib structure; if transportation is inconvenient, a general four-tube truss rib structure can still be adopted, and only the steel tube concrete needs to be replaced with a steel tube core wrapped with UHPC structure. This type of arch rib structure has the characteristics of low segment hoisting weight, good apparent durability, and low construction measures. It can realize the rapid construction of highly prefabricated and assembled arch rib segments, ensure construction quality, simplify construction methods and shorten construction periods, and solve the durability problems of large-span concrete arch bridges, heavy weight, difficult welding of thick steel plates 117 of steel box or steel truss arch bridges, and the life-long maintenance cost of steel tube concrete arch bridges. For this type of arch rib structure, the present invention proposes an arch rib connection node based on flange connection, which eliminates the workload of high-altitude welding and reduces the construction difficulty and safety risks of high-altitude operations.

[0097] This embodiment introduces large-diameter circular steel tube arch ribs and UHPC materials based on the combined characteristics of multi-tube truss rib steel tube concrete structure and rigid skeleton outer concrete structure, and considers the reasonable matching principle of main arch strength, structural stiffness and overall stability, and proposes two arch bridge configurations that can be constructed using mature cable 33 suspension and inclined stay buckle hanging system. Configuration 1 is an assembled double circular steel tube inner core outer UHPC arch bridge, and the arch rib cross-section adopts double single circular tube, which is suitable for spans within 300m; Configuration 2 adopts double-limb or double-four-limb steel tube inner core outer UHPC truss rib cross-section, which is suitable for large-span arch bridges over 300m. The upper and lower parallel links and wind bracings between the arch ribs of the two schemes are made of weather-resistant steel tubes or steel tube cores with UHPC composite structures. The arch columns 3 and bridge deck beams 6 are designed as assembled UHPC structures to achieve low maintenance throughout the life cycle: Furthermore, the ratio of the elastic modulus of high-strength steel to UC140 is, and the design value of the compressive strength of UC140 is 68MPa. Since UHPC and the steel tube core are prefabricated in the factory at one time, the design strength of the high-strength steel corresponding to UHPC is estimated to be 4.65×68MPa=316MPa, which is consistent with the design strength range of Q420 steel. Therefore, if UC140 and Q420 high-strength steel are matched and subjected to force together, the excellent performance of the two materials can be fully utilized. In other cases, such as UC120 and Q390 or Q345, they also have good matching properties; steel The cross-sectional area of ​​the composite structure of the inner core of the tube and the outer cover of UHPC (steel: Q420; UHPC: UC140) is 70% of that of the steel tube concrete structure (steel: Q420; concrete: C80) at the same strength. Obviously, the self-weight is reduced and the structural size can be reduced to achieve lightweight structure. For the anchoring of the hanger, the connection of the upper and lower flat joints and the wind brace, it is more convenient and reasonable to use steel structure to deal with it. The steel tube can be used as the prefabricated inner mold of UHPC. The minimum wall thickness of the steel tube should meet the deformation requirements of the steel tube during factory prefabrication. The thickness of the steel tube is thickened at the nodes, hangers, upper and lower flat joints and wind brace connection positions, and stiffening plates and bolts are set to ensure local force. The low water-cement ratio and high cementitious material content of UHPC will cause it to show a large self-shrinkage characteristic during the curing process, especially in the early stage. This self-shrinkage is generally difficult to match the deformation characteristics of steel during the strength formation process, and may produce large stress inside the outer cover UHPC and the steel-UHPC interface, resulting in apparent cracking. The volume change caused by the full-time shrinkage creep of UHPC can be regulated by adding materials such as shrinkage reducing agent, internal curing agent and expansion agent, so as to achieve deformation coordination between the steel pipe and the outer UHPC and prevent the occurrence of cracks; the columns and bridge deck beam 6 are both prefabricated and assembled structures; the columns are assembled UHPC thin-walled rectangular columns, and the deadweight can be reduced to more than half compared with concrete columns; the bridge deck beam 6 is an assembled pre-stressed UHPC beam, and the deadweight per square meter is only about 10%-20% higher than that of the steel-concrete composite beam with the same span;

[0098] Specifically, the prefabricated steel tube inner core and UHPC outer shell arch bridge of this embodiment includes two configurations suitable for different spans, and the difference between the two configurations lies in the change of the arch rib cross-section: Configuration one is an assembled double circular steel tube inner core and UHPC outer shell arch bridge, and the arch rib cross-section adopts double single circular tubes, and the outer diameter of the single circular tube arch rib 1 is generally not more than 4.0m. This bridge type is suitable for arch bridges with a span range of less than 300m; Configuration two adopts the truss rib cross-section of double four-limb steel tube inner core and UHPC outer shell, and the outer diameter of the arch rib is generally not more than 2.0m, which is suitable for large-span arch bridges with a span of more than 300m. The main arch rib structure of the two configurations is a steel tube inner core and an outer UHPC structure. The arch rib is formed by connecting the inner hollow circular steel tube. The hollow steel tube 111 is wrapped with a layer of UHPC outer layer 211. The UHPC outer layer 211 can protect the inner steel tube from corrosion and has excellent durability. In addition, the inner steel tube can be used as a casting template for UHPC to simplify the construction process. In this embodiment, the arch rib structure matches UHPC with weather-resistant high-strength steel to bear force together, giving full play to the excellent properties of the two materials, and has excellent compression and corrosion resistance. However, the low water-cement ratio and high cementitious material content of UHPC will cause it to exhibit a large self-shrinkage characteristic during the coagulation and hardening process, especially in the early stage, making it generally difficult for UHPC to match the deformation characteristics of steel during the strength formation process, thereby generating a large stress and causing the apparent cracking of UHPC. In this embodiment, the shrinkage deformation of UHPC is reduced by compounding the internal curing agent and the expansion agent, so as to achieve deformation coordination between the steel tube and the outer UHPC, and further improve the performance of the composite structure. The prefabricated steel tube inner core and UHPC outer shell arch bridge of this embodiment, the configuration one includes double circular tube arch ribs, and arch columns 3 and cap beams 5 connecting the bridge deck structure and the arch ribs, the arch ribs are inclined inwards by about 8°, forming a basket type, the upper and lower parallel links and wind bracing and other connecting rods between the arch ribs are steel structures, the minimum wall thickness of the steel tube should meet the steel tube deformation requirements during factory prefabrication, the arch columns 3, the bridge deck beam 6 and the cap beam 5 are all designed as prefabricated UHPC structures to achieve low maintenance during a long life cycle: the arch columns 3 are prefabricated UHPC thin-walled rectangular columns, the deadweight can be reduced by about 60% compared with concrete columns, and the quarter span to the arch foot section is also inclined inwards, the inclination angle is consistent with the arch rib angle, the rest are upright, and a transverse connection is added between the columns. The cap beam 5 adopts a prefabricated hollow UHPC structure, on which a support is arranged to provide a simple support for the bridge deck beam 6. The bridge deck beam 6 is composed of eleven T-shaped beams (nine middle beams and two side beams), and the top of the beam is set with 20cm thick C50 concrete and 10cm thick asphalt concrete for bridge deck paving. The T-beam adopts assembled prestressed UHPC beam, and the construction adopts single beam prefabrication and installation. Each T-beam is connected with a 3-5cm thick prefabricated UHPC board (also used as a template), and a cross diaphragm is set at each support point and mid-span. The self-weight per square meter of this type of bridge deck beam 6 is only about 10%-20% higher than that of the steel-concrete composite beam with the same span;

[0099] The assembled steel tube inner core and UHPC outer shell arch bridge of this embodiment has a second configuration including double four-legged truss arch ribs, which are four-legged truss steel tube inner core and UHPC outer shell arch ribs 10, as well as arch columns 3 and cap beams 5 connecting the bridge deck structure and the arch ribs. The arch ribs are not inclined inward, and the upper and lower parallel connections and wind bracing and other connecting rods between the arch ribs are made of steel structure. The minimum wall thickness of the steel tube should meet the steel tube deformation requirements during factory prefabrication; the structural forms of the arch columns 3, cap beams 5 and bridge deck beams 6 are the same as those of the above-mentioned configuration one; the arch columns 3 are all upright. Since the span of configuration two is long and the rise is large, the arch columns 3 adopt a variable cross-section form with thick bottom and thin top in the section from one-quarter of the span to the arch foot. The assembled steel pipe-wrapped UHPC arch rib node based on flange connection in this embodiment includes: an inner hollow steel pipe 111 combining a cylindrical and a conical shape, a prefabricated UHPC outer cladding 112 using the inner hollow steel pipe 111 as a casting template, a flange welded to the end of the conical section of the hollow steel pipe 111, a flange stiffening steel plate 114 uniformly welded to the inner hollow steel pipe 111 of the conical section along the circumferential direction of the flange, radial shear nails uniformly welded side by side in the circumferential direction at the interface between the steel pipe and the UHPC outer cladding 211 on both sides of the flange, a steel plate 117 provided from the prefabricated UHPC section to the cast-in-place UHPC section, shear nails welded to the steel plate 117 staggered with the shear nails on the steel pipe, the flange is bolted with bolts after the end of the inner steel pipe is accurately docked, and the UHPC outer cladding 211 at the node connection is cast on site after the flange is bolted. Among them, the steel plate 117 and the shear nails may not be provided. In this embodiment, the steel plate 117 and the shear nails are only provided at the connection nodes using the outer flange; they are not provided at the connection nodes using the inner flange. In this embodiment, the steel plate 117 is provided from the prefabricated UHPC section to the cast-in-place UHPC section, and the shear nails are welded on the steel plate 117 in an alternating manner with the shear nails on the steel pipe, which can enhance the shear resistance of the connection and improve the continuity of the outer UHPC layer and the integrity of the structure. In this embodiment, the length of the steel plate 117 in the prefabricated UHPC section is twice its length in the cast-in-place UHPC section, and the steel plate 117 is aligned with the boundary of the shear nails. In this embodiment, the steel pipe at the connection is inwardly inclined from the prefabricated UHPC section to the cast-in-place UHPC section, and the length of the shear nails welded on the straight section of the inner steel pipe is equal to the axial length of the inwardly inclined section. The inwardly inclined angle of the steel pipe is about 10°. This implementation method can increase the cross-sectional thickness of the UHPC at the flange joint and improve the bearing capacity of the node connection. In this embodiment, the flange stiffening steel plates 114 are arranged at equal intervals along the flange circumferentially, and 7-10 stiffening steel plates 117 are arranged on one side; the connecting bolts 115 are located in the middle of two adjacent stiffening steel plates 117, and are bolted at equal intervals on the flange circumferentially, and the number is the same as the number of stiffening steel plates 117 on one side. The staggered arrangement of the stiffening steel plates 117 and the connecting bolts 115 makes the force at the flange joint more uniform, reduces the spatial distortion generated by the arch rib when bearing, and thus improves the stability and bearing capacity of the structure.In this embodiment, the shear nails and the shear nails of the inner steel pipe interface are arranged at equal intervals along the axial direction of the arch rib segment, and the shear nails on the steel plate 117 and the shear nails on the inner steel pipe interface are arranged at equal intervals in the axial and circumferential directions to ensure that there is a certain thickness of concrete protective layer between the steel plate shear nails 118 and the steel pipe shear nails. In this embodiment, the steel pipe outwrapped UHPC arch rib node based on flange connection can be connected by an external flange or an internal flange. The advantage of the external flange over the internal flange is that the construction is more convenient and the manual operation is easier. Since the UHPC wraps the flange and the stiffening steel plate 117, the stability and reliability of the node can be improved. Compared with the external flange, the internal flange can realize the welding of the outer side of the steel pipe. The disadvantage is that if the diameter of the steel pipe is small, it is not easy for workers to enter the inside for operation. In this embodiment, the installation construction of the steel tube core of the present invention and the UHPC arch ribs are covered by the inclined buckle hanging method, and the inclined buckle hanging lifting system structure layout includes ground anchors 31, towers 32, cables 33 and buckle cables 34. It should be noted that the inclined buckle hanging lifting system structure layout diagram is only used as a schematic in this embodiment, and the specific implementation process does not only include the structure. In the above embodiment, the arch ribs are constructed by synchronous lifting on both sides twice. It is recommended that the non-jointed arch rib segments are connected by internal flanges, and the jointed segments are connected by external flanges as the preferred connection method.

[0100] Example 3

[0101] In another embodiment of the present invention, a method for using a fabricated steel pipe inner core and outer UHPC arch rib connection node is provided, comprising:

[0102] Step 1: The hollow steel pipe 111 is manufactured and processed in a steel structure processing plant, and after the on-site docking flange 113, steel plate 117 and shear nails are welded, it is transported to a concrete prefabrication plant for pouring the UHPC outer layer 211, and moisture-curing and steam curing are performed according to the design and specification requirements to form an assembled steel pipe inner core and UHPC outer layer arch rib segment;

[0103] Step 2: After the construction of the arch seat is completed, the tower 32 and the anchor 31 of the inclined buckle hanging hoisting system are constructed, and the system is installed and debugged to check the reliability of the hoisting system;

[0104] Step 3: transporting the prefabricated arch rib segments in the factory to the bridge construction site by means of a transport barge 41, and hoisting the arch rib segments;

[0105] Step 4: After adjusting the spatial posture of the single circular arch rib 1 to the corresponding position and angle by tensioning the inclined cable 34, the inner steel pipe end is precisely docked with the on-site docking flange 113, and the flange is bolted after the linear shape of the single circular arch rib 1 is controlled;

[0106] Step 5: After the single circular tube arch rib 1 segment is installed and inspected to be qualified, cast-in-place UHPC outer cladding 119 is poured.

[0107] From the above description, it can be seen that the above embodiments of the present invention achieve the following technical effects:

[0108] The steel pipe is used as the inner mold and UHPC is wrapped on the outside to form a new structure of a composite arch bridge. The steel pipe can be used as a UHPC casting template. The main arch ribs of the arch bridge are mainly under pressure. UHPC has excellent compressive resistance. Matching UHPC with weather-resistant high-strength steel to bear the force together can save materials and reduce the deadweight of the structure, thereby improving the spanning capacity of the bridge.

[0109] Due to the superior crack resistance and durability of UHPC, the corrosion of internal steel can be avoided to the greatest extent, the durability of the bridge structure can be improved, its service life can be extended, and the maintenance and repair costs during operation can be reduced.

[0110] The cross-section of the steel tube core wrapped with UHPC arch ribs is formed in one step, and the structural force is clear. Although the dead weight of a single segment is large and there are many hoisting segments, it eliminates the tedious work of pouring concrete inside the traditional steel tube concrete arch bridge and wrapping concrete on the rigid skeleton concrete arch, which can speed up the construction process.

[0111] In addition to the arch rib segments adopting highly prefabricated assembled structures, the arch columns 3 and the bridge deck beams 6 also adopt prefabricated assembled UHPC structures, realizing highly prefabricated, assembled and precise aerial installation construction of lightweight arch ribs and superstructures, and achieving high durability, long life and low maintenance for the entire bridge.

[0112] Compared with the traditional arch rib segment welding method using dry joints, the arch rib segment connection nodes of the present invention use a combination of flange bolting and UHPC wet joints, which can eliminate the workload of high-altitude welding and reduce the construction difficulty of high-altitude operations; and the concrete thickness is locally thickened at the joints, a stiffening steel plate 117 is added, and shear nails are welded to improve the stability and integrity of the connection nodes.

[0113] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An assembled steel pipe core-wrapped UHPC arch rib connection node, characterized in that: It comprises hollow steel pipes, which are arranged in sections, and the outer diameter of each hollow steel pipe is covered with a prefabricated UHPC outer cladding. The connecting ends of adjacent hollow steel pipes are provided with on-site docking flanges, and the adjacent hollow steel pipes are connected through on-site docking flanges and connecting bolts. The outer diameters of adjacent hollow steel pipes near the connecting ends are provided with a plurality of steel pipe shear nails and flange stiffening steel plates. The adjacent hollow steel pipes are sleeved with steel plates, and the inner walls of the steel plates are provided with steel plate shear nails. The connecting ends of adjacent hollow steel pipes are provided with cast-in-place UHPC outer claddings.

2. The assembled steel pipe core-wrapped UHPC arch rib connection node according to claim 1, characterized in that: At the connection of the unit tube arch rib segments, the hollow steel pipe adopts an inwardly inclined structure from the prefabricated UHPC outer cladding to the cast-in-place UHPC outer cladding, and steel pipe shear nails are arranged in the inwardly inclined structure section, and the steel pipe shear nails are uniformly welded on the steel pipe in the circumferential direction.

3. The assembled steel tube core-wrapped UHPC arch rib connection node according to claim 1, characterized in that: The steel plate is arranged from the prefabricated UHPC outer cladding section to the cast-in-place UHPC outer cladding section, and steel plate shear nails are uniformly welded on the steel plate, and the steel plate shear nails and the steel pipe shear nails on the steel pipe are arranged alternately.

4. The assembled steel pipe core-wrapped UHPC arch rib connection node according to claim 1, characterized in that: The hollow steel pipe adopts a cylindrical and conical combined structure, and the hollow steel pipe is used as a prefabricated UHPC outer cladding and an on-site UHPC outer cladding casting template.

5. The assembled steel pipe inner core and UHPC arch rib connection node according to claim 1, characterized in that: The length of the steel plate in the prefabricated UHPC outer cladding section is twice its length in the cast-in-place UHPC outer cladding section, and the steel plate is aligned with the boundary of the shear studs.

6. An arch bridge with an assembled steel tube core and UHPC arch ribs, based on the assembled steel tube core and UHPC arch rib connection node according to any one of claims 1 to 5, characterized in that: include: reinforced concrete abutments; A single circular tube arch rib, both ends of which are connected to reinforced concrete arch seats; The arch columns include a plurality of arch columns, and the lower ends of the arch columns are connected to the single circular tube arch rib; A cap beam, the cap beam being arranged at the upper end of the single circular tube column; A bridge deck beam, wherein the bridge deck beam is arranged at the upper end of the cap beam; Arch rib wind bracing, wherein the arch rib wind bracing is arranged between the single circular tube arch ribs; Prestressed steel bars for bridge deck beams, wherein the prestressed steel bars for bridge deck beams are arranged in the bridge deck beams; UHPC prefabricated panels, wherein the UHPC prefabricated panels are arranged between adjacent bridge deck beams; A ground anchor, the ground anchor being arranged on the ground; as well as A tower, wherein the tower is arranged vertically; A cable, wherein both ends of the cable are respectively connected to the tower; A cable, one end of which is connected to the tower frame, and the other end of which is connected to the single circular tube arch rib.

7. The assembled steel tube core-wrapped UHPC arch rib connection node according to claim 6, characterized in that: The arch columns and bridge deck beams both adopt prefabricated assembled structures, the columns adopt assembled UHPC thin-walled rectangular columns, and the bridge deck beams adopt assembled pre-tensioned prestressed UHPC beams.

8. The fabricated steel tube core-wrapped UHPC arch rib connection node according to claim 6, characterized in that: A buckle cable is suspended at the connection of each single-circular tube arch rib segment, and the buckle cable provides a hanging tension at the connection of the single-circular tube arch rib segment.

9. The fabricated steel tube core-wrapped UHPC arch rib connection node according to claim 6, characterized in that: The cable is also connected to the ground anchor.

10. A construction method for a prefabricated steel pipe core-wrapped UHPC arch rib connection node, characterized in that: include: Step 1: The hollow steel pipe is manufactured and processed in the steel structure processing plant, and after the on-site docking flange, steel plate and shear nails are welded, it is transported to the concrete prefabrication plant to cast the UHPC outer layer. Moisture curing and steam curing are carried out according to the design and specification requirements to form an assembled steel pipe inner core and UHPC outer layer arch rib segment; Step 2: After the construction of the arch seat is completed, the tower and anchor of the inclined buckle hanging hoisting system are constructed, and the system is installed and debugged to test the reliability of the hoisting system; Step 3: transport the prefabricated arch rib segments in the factory to the bridge construction site by transport barges, and hoist the arch rib segments; Step 4: After adjusting the spatial posture of the single circular arch rib to the corresponding position and angle by tensioning the inclined cable, the inner steel pipe end is used to accurately dock the on-site docking flange, and the flange is bolted after the linear shape of the single circular arch rib is controlled; Step 5: After the single circular tube arch rib segment installation inspection is passed, cast-in-place UHPC outer cladding.

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