Large-span box-type arch bridge reinforced by UHPC (Ultra High Performance Concrete)
By using UHPC reinforcement at the top and bottom slabs of the box arch bridge, combined with a special arrangement of longitudinal reinforcing bars, the reinforcement problem of large-span box arch bridges was solved, achieving improved load-bearing capacity and reduced construction risks.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-15
- Publication Date
- 2026-03-03
AI Technical Summary
Existing technologies lack effective reinforcement methods suitable for long-span box arch bridges. Conventional reinforcement methods suffer from problems such as high self-weight, high construction risk, high steel plate void rate, and insufficient load-bearing capacity.
UHPC reinforcement is used at both the top and bottom slabs of the box arch bridge. By setting shear bars on the bottom and top surfaces, longitudinal reinforcing bars and UHPC reinforcement layers, combined with a special arrangement of longitudinal reinforcing bars, construction risks are reduced and load-bearing capacity is improved.
It significantly improves the load-bearing capacity of box arch bridges, reduces wet weight and risks during construction, prevents cracks in arch bridges, and is suitable for large-span box arch bridges with spans exceeding 100m.
Smart Images
Figure CN223963846U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of bridge reinforcement engineering technology, and in particular to a large-span box arch bridge reinforced with UHPC. Background Technology
[0002] Reinforced concrete box arch bridges are assembled from multiple precast box cells, possessing advantages such as high torsional stiffness, strong structural stability, and good overall performance. Box arch bridges are generally upper-bearing arch bridges, well-suited to mountainous and riverside terrain, and were widely used in western my country in the 1980s. Due to the limitations of the socio-economic level and bridge construction technology at the time, to save materials and reduce lifting weight, precast box arches generally have a high hollow ratio and thin top and bottom slabs to facilitate assembly. In recent years, with the rapid development of my country's transportation industry, increasing traffic flow, and a rapid increase in heavy vehicles, bridges are operating under excessive loads. Many box arch bridges that have been in operation for over 20 years are prone to insufficient load-bearing capacity and rapid deterioration, posing certain safety hazards.
[0003] The reinforcement of box arch bridges commonly employs two methods: self-compacting concrete (SCC) to enlarge the cross-section and steel plate bonding. SCC is simple and adaptable, but for large-span box arches with high hollow sections in the arch ribs and spans exceeding 100 meters, the self-compacting concrete reinforcement layer is heavy, and the wet weight of the concrete is directly borne by the original arch ribs during construction, posing a significant construction risk. Steel plate bonding offers a shorter construction period, simpler construction, and less wet work, but the steel plates require corrosion protection. Furthermore, the curved surfaces of the arch ribs are difficult to bond, and the poor compatibility between the steel plates and the substrate easily leads to voiding. In bridge inspection and reinforcement work, the applicant encountered a box arch bridge where, after 5 years of steel plate bonding reinforcement, the voiding rate reached 32% of the total sampled bridges, with 10 plates completely detached. Another bridge, after 10 years of operation, showed severe aging of the adhesive on the steel plates, resulting in a voiding rate exceeding 50%, and the steel plates were severely corroded. These two bridge reinforcement cases, while individual examples, highlight common problems.
[0004] Furthermore, conventional reinforcement methods for box arch bridges typically involve increasing the cross-section or bonding steel plates to the bottom of the arch ribs, with protective arches usually only added at the arch foot. However, in its bridge inspection and reinforcement work, the applicant has found that for box arch bridges with spans exceeding 100m, due to the high hollowness of the box section and the relatively small cross-section of the arch ribs, even after reinforcement at the bottom of the arch ribs, the load-bearing capacity still cannot meet the requirements. In summary, the applicant has found that there is currently a lack of a superior solution for the reinforcement of large-span box arch bridges; therefore, it is necessary to explore a new reinforcement technology suitable for large-span box arch bridges. Utility Model Content
[0005] This utility model discloses a large-span box arch bridge reinforced with UHPC. UHPC is used to reinforce both the top and bottom plates of the box arch bridge, resulting in good reinforcement effect and significantly improving the load-bearing capacity of the box arch.
[0006] To achieve the above objectives, the technical solution of this utility model is as follows:
[0007] A large-span box arch bridge reinforced with UHPC includes the original concrete box arch and the superstructure columns, and also includes:
[0008] The bottom shear reinforcement is inserted at intervals into the bottom surface of the original concrete box arch;
[0009] The longitudinal reinforcing bars at the bottom surface are spaced longitudinally on the bottom surface of the original concrete box arch and are connected and fixed to the bottom shear bars.
[0010] The bottom UHPC reinforcement layer is set on the bottom surface of the original concrete box arch, covering the bottom shear reinforcement and the bottom longitudinal reinforcing steel.
[0011] Top surface shear reinforcement bars are inserted at intervals into the top surface of the original concrete box arch;
[0012] The top longitudinal reinforcing bars are longitudinally spaced on the top surface of the original concrete box arch and are connected and fixed to the top shear bars. They include a first top longitudinal reinforcing bar and a second top longitudinal reinforcing bar. The first and second top longitudinal reinforcing bars are alternately and equidistantly arranged. At the connection position between the original concrete box arch and the arch column, the first top longitudinal reinforcing bar extends beyond the top surface of the original concrete box arch by a distance d1 and passes through the arch column. The second top longitudinal reinforcing bar extends beyond the top surface of the original concrete box arch by a distance d2 and passes through the arch column. d1 and d2 are not equal.
[0013] The top UHPC reinforcement layer is installed on the top surface of the original concrete box arch, covering the top shear reinforcement and the top longitudinal reinforcing steel bars.
[0014] Furthermore, the bottom longitudinal reinforcing bars include a first bottom longitudinal reinforcing bar and a second bottom longitudinal reinforcing bar. The first bottom longitudinal reinforcing bar and the second bottom longitudinal reinforcing bar are arranged alternately at equal intervals. At the connection position between the original concrete box arch and the arch seat, the first bottom longitudinal reinforcing bar and the second bottom longitudinal reinforcing bar are inserted into the arch seat at different height positions.
[0015] A connecting base is provided on the outside of the arch seat. The connecting base is connected to the bottom UHPC reinforcement layer and covers the first bottom longitudinal reinforcing steel bar and the second bottom longitudinal reinforcing steel bar.
[0016] Furthermore, the original concrete box arch, bridge deck, and the space between the two arch columns located in the middle are filled with arch filler.
[0017] Furthermore, the spacing between the bottom shear reinforcement and the top shear reinforcement is 0.4-0.5m, arranged in a quincunx pattern.
[0018] Furthermore, it also includes bottom transverse reinforcing bars, which are horizontally spaced on the bottom surface of the original concrete box arch, with a diameter not exceeding 16mm, and the spacing between the bottom transverse reinforcing bars is 10-15cm.
[0019] Furthermore, it also includes transverse reinforcing bars on the top surface, which are arranged transversely at intervals on the top surface of the original concrete box arch, with a diameter not exceeding 16mm, and the spacing between the transverse reinforcing bars on the top surface is 10-15cm.
[0020] Furthermore, the diameter of the bottom longitudinal reinforcing bars is no greater than 16mm, and the spacing between the bottom longitudinal reinforcing bars is 10-15cm; the diameter of the top longitudinal reinforcing bars is no greater than 16mm, and the spacing between the top longitudinal reinforcing bars is 10-15cm.
[0021] Furthermore, d1 is 10-15cm; d2 is greater than d1 (10-15cm).
[0022] Furthermore, the thickness of the bottom UHPC reinforcement layer is 5-10cm.
[0023] Furthermore, at the connection point between the top UHPC reinforcement layer and the arch column, the thickness exceeds the maximum height of the longitudinal reinforcing steel bars on the top surface by 3-5 cm, while the thickness of the top UHPC reinforcement layer at other locations is 5-10 cm.
[0024] The large-span box arch bridge reinforced with UHPC described above has the following advantages:
[0025] (1) This utility model uses UHPC to reinforce the bottom plate of the box arch, which has a good reinforcement effect and greatly improves the load-bearing capacity. Moreover, the weight of the UHPC reinforcement layer can be reduced by about 60% compared with the weight of conventional self-compacting concrete. The wet weight of the concrete is small during construction, and the construction risk is small. It is especially suitable for large-span box arch bridges with a span of more than 100m.
[0026] (2) The tensile strength of UHPC is over 10MPa. The high tensile strength can effectively prevent the generation and development of box arch cracks and solve the problem of longitudinal cracks easily appearing at the joint of box chambers.
[0027] (3) The thickness of the top UHPC reinforcement layer is small, resulting in a small distance between the top longitudinal reinforcement and the top of the arch. If the top longitudinal reinforcement is arranged in the conventional way at the position of the arch column, there is a problem that the drilling machine cannot drill holes at the position of the arch column near the top of the arch. To solve the above problem, this utility model sets the top longitudinal reinforcement at the arch column to be a certain distance higher than the original concrete box arch top surface. At the same time, in order to prevent the concrete from being drilled out due to the dense spacing of the drilling holes in the arch column, the top longitudinal reinforcement at the position of the arch column is arranged in two rows. In this way, the spacing of each row of drilling holes in the arch column is twice the spacing of the top longitudinal reinforcement, which can better prevent the concrete of the arch column from being drilled out.
[0028] (4) The present invention is provided with longitudinal reinforcing bars on the bottom surface inserted into the arch seat, and a connecting base is provided at the junction of the bottom UHPC reinforcement layer and the arch seat. This can increase the contact area between the bottom UHPC reinforcement layer and the arch seat, and can better transfer the self-weight of the bottom UHPC reinforcement layer and the load it bears to the arch seat. In addition, when the longitudinal reinforcing bars on the bottom surface are inserted into the arch seat, they are also inserted at different heights, which can effectively avoid the phenomenon of the arch seat concrete being drilled out due to excessively dense drilling spacing. Attached Figure Description
[0029] Figure 1 This is a schematic diagram of the elevation structure of an embodiment of the present invention.
[0030] Figure 2 This is a cross-sectional structural diagram of an embodiment of the present invention (the columns on the arch are omitted).
[0031] Figure 3 This is a structural schematic diagram of the longitudinal reinforcing steel bars on the top surface at the connection point between the top UHPC reinforcement layer and the arch column.
[0032] Figure 4 yes Figure 3 A schematic diagram of the BB structure.
[0033] Figure 5 yes Figure 1 A magnified structural diagram of point A in the middle.
[0034] In the figure, the original concrete box arch is 1, the bottom UHPC reinforcement layer is 2, the top UHPC reinforcement layer is 3, the connection position between the top UHPC reinforcement layer and the arch column is 301, the arch column is 4, the arch fill is 5, the top longitudinal reinforcing bar is 6, the first top longitudinal reinforcing bar is 601, the second top longitudinal reinforcing bar is 602, the bottom longitudinal reinforcing bar is 7, the first bottom longitudinal reinforcing bar is 701, the second bottom longitudinal reinforcing bar is 702, the arch seat is 8, and the connecting base is 9. Detailed Implementation
[0035] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present utility model without creative effort are within the scope of protection of the present utility model.
[0036] In the description of this utility model, it should be noted that the terms "upper" and "lower" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the utility model product is usually placed during use. They are only used to facilitate the description of this utility model and to simplify the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.
[0037] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.
[0038] A large-span box arch bridge reinforced with UHPC, combined with Figure 1 and Figure 2As shown, the structure includes the original concrete box arch 1 and the columns 4 on top of the arch, as well as bottom shear reinforcement, bottom longitudinal reinforcement 7, bottom UHPC reinforcement layer 2, top shear reinforcement, top longitudinal reinforcement 6, and top UHPC reinforcement layer 3. Specifically: the bottom shear reinforcement is inserted at intervals into the bottom surface of the original concrete box arch 1. Before insertion, the bottom surface of the original concrete box arch 1 is roughened, and then inserted according to conventional construction methods, so that the subsequently poured bottom UHPC reinforcement layer 2 can work synergistically with the structural layer of the original concrete box arch 1. The bottom longitudinal reinforcement 7 is longitudinally spaced on the bottom surface of the original concrete box arch 1 and connected and fixed to the bottom shear reinforcement. The bottom longitudinal reinforcement 7 is generally installed along the longitudinal length of the original concrete box arch 1. The bottom UHPC reinforcement layer 2 is placed on the bottom surface of the original concrete box arch 1, covering the bottom shear reinforcement and the bottom longitudinal reinforcement. The top shear reinforcement is inserted at intervals into the top surface of the original concrete box arch 1. Before insertion, the top surface of the original concrete box arch 1 is roughened, and then the reinforcement is inserted according to the conventional construction method so that the subsequently poured top UHPC reinforcement layer 3 can work together with the original concrete box arch 1 structural layer. The longitudinal reinforcing bars 6 on the top surface are spaced longitudinally on the top surface of the original concrete box arch 1 and are connected and fixed to the top shear reinforcement. The longitudinal reinforcing bars 6 are generally installed along the entire longitudinal length of the original concrete box arch 1. However, due to the presence of the arch support column 4, the longitudinal reinforcing bars 6 cannot run directly through the arch support column 4; holes need to be drilled in the arch support column 4 to pass through the reinforcing bars. The thickness of the top UHPC reinforcement layer 3 is relatively small, resulting in a small distance between the longitudinal reinforcing bars 6 and the arch top. If the longitudinal reinforcing bars 6 are arranged in the conventional way at the location of the arch support column 4, there is a problem that the drilling rig cannot drill holes near the arch top of the arch support column 4. To solve the above problem, this embodiment has made a special design for the arrangement of the longitudinal reinforcing bars 6 passing through the arch support column 4: combined with... Figure 3 and Figure 4 As shown, the top longitudinal reinforcing bars 6 include a first top longitudinal reinforcing bar 601 and a second top longitudinal reinforcing bar 602. The first top longitudinal reinforcing bars 601 and the second top longitudinal reinforcing bars 602 are arranged alternately at equal intervals. At the connection position between the original concrete box arch 1 and the arch column 4, the first top longitudinal reinforcing bar 601 extends beyond the top surface of the original concrete box arch 1 by a distance d1 and passes through the arch column 4, and the second top longitudinal reinforcing bar 602 extends beyond the top surface of the original concrete box arch 1 by a distance d2 and passes through the arch column 4. For column 4, d1 and d2 are not equal. The presence of d1 and d2 here provides sufficient drilling space for the drilling rig. In this embodiment, the longitudinal reinforcing steel bars 6 on the top surface of the column 4 on the arch are arranged in two rows. In this way, the spacing between each row of holes in the column 4 on the arch is twice the spacing between the longitudinal reinforcing steel bars 6 on the top surface, which can better prevent the concrete from being drilled out due to excessively dense hole spacing in the column 4 on the arch. The top UHPC reinforcement layer 3 is set on the top surface of the original concrete box arch 1, covering the top shear reinforcement and the top longitudinal reinforcing steel bars.
[0039] During construction, the UHPC reinforcement layer 2 on the bottom surface requires formwork support, utilizing the self-compacting and defect-filling properties of UHPC. The UHPC reinforcement layer 3 on the top surface only requires side formwork support, again leveraging the self-compacting and defect-filling properties of UHPC to ensure effective reinforcement after construction. This embodiment uses UHPC reinforcement in both the bottom slab of the box arch, resulting in excellent reinforcement, significantly increased load-bearing capacity, and a weight reduction of approximately 60% compared to conventional self-compacting concrete. This reduces the wet weight of the concrete during construction, minimizing construction risks, making it particularly suitable for large-span box arch bridges with spans exceeding 100m. Furthermore, UHPC has a tensile strength exceeding 10MPa, effectively preventing the generation and development of cracks in the box arch and resolving the issue of longitudinal cracks easily appearing at the joints between box sections.
[0040] Furthermore, the bottom longitudinal reinforcing bars 7 include a first bottom longitudinal reinforcing bar 701 and a second bottom longitudinal reinforcing bar 702. The first bottom longitudinal reinforcing bars 701 and the second bottom longitudinal reinforcing bars 702 are arranged alternately and at equal intervals. At the connection position between the original concrete box arch 1 and the arch seat 8, the first bottom longitudinal reinforcing bars 701 and the second bottom longitudinal reinforcing bars 702 are inserted into the arch seat at different height positions, similar to the arrangement of the top longitudinal reinforcing bars 6 at the arch column 4. Generally, of the first bottom longitudinal reinforcing bars 701 and the second bottom longitudinal reinforcing bars 702, one set extends to the arch seat 8 near the bottom in the height direction, and the other set extends to the arch seat 8 at the middle in the height direction, so as to better integrate with the arch seat 8. A connecting base 9 is provided on the outside of the arch seat 8. The connecting base 9 is connected to the bottom UHPC reinforcement layer 2 and covers the first bottom longitudinal reinforcing bars 701 and the second bottom longitudinal reinforcing bars 702. By inserting the bottom longitudinal reinforcing steel bars 7 into the arch seat 8, and setting the connecting base 9 at the junction of the bottom UHPC reinforcement layer 2 and the arch seat 8, the contact area between the bottom UHPC reinforcement layer 2 and the arch seat 8 can be increased, which can better transfer the self-weight and load borne by the bottom UHPC reinforcement layer 2 to the arch seat 8. In addition, when the bottom longitudinal reinforcing steel bars 7 are inserted into the arch seat 8, they are also inserted at different heights, which can effectively avoid the phenomenon of the arch seat concrete being drilled out due to excessively dense drilling spacing.
[0041] Furthermore, the original concrete box arch 1 is filled with arch filler 5 above the mid-span top surface, below the bridge deck, and between the two arch columns 4 in the middle. If the original box arch bridge has arch filler, the original arch filler is removed before constructing the top UHPC reinforcement layer 3.
[0042] Furthermore, the spacing between the bottom shear reinforcement and the top shear reinforcement is 0.4-0.5m, arranged in a quincunx pattern. Selecting appropriate spacing between the bottom and top shear reinforcement can effectively control the weight of the reinforced structure and ensure its synergistic effect with the stability of the original concrete box arch 1 structural layer.
[0043] Furthermore, it also includes bottom transverse reinforcing bars, which are horizontally spaced on the bottom surface of the original concrete box arch 1, i.e., along the width of the arch bridge, and perpendicularly intersecting with the bottom longitudinal reinforcing bars 7. They are connected to the bottom shear reinforcement. The bottom transverse reinforcing bars generally run the entire length of the original concrete box arch 1. Due to the thinness of the UHPC reinforcement layer, the diameter of the bottom transverse reinforcing bars is no greater than 16mm, and the spacing between them is 10-15cm. CFRP bars can be preferentially used within the UHPC reinforcement layer to reduce the diameter of the bottom transverse reinforcing bars; alternatively, commonly used HRB400 grade bars can also be used. Similarly, it also includes top transverse reinforcing bars, which are horizontally spaced on the top surface of the original concrete box arch 1 and connected to the top shear reinforcement. The top transverse reinforcing bars generally run the entire length of the original concrete box arch 1, with a diameter no greater than 16mm, and the spacing between them is 10-15cm.
[0044] Similarly, the diameter of the bottom longitudinal reinforcing bars 7 and the top longitudinal reinforcing bars 6 should not exceed 16mm, and the spacing between the bottom longitudinal reinforcing bars 7 and the top longitudinal reinforcing bars 6 should be 10-15cm. CFRP bars can be preferred to reduce the diameter of the longitudinal reinforcing bars, but commonly used HRB400 grade bars can also be used.
[0045] Furthermore, d1 is 10-15cm to leave adequate drilling space for the drilling rig; d2 is greater than d1 by 10-15cm to better prevent concrete collapse during drilling.
[0046] Furthermore, to ensure the reinforcement effect at the bottom of the concrete box arch and to reasonably control the weight of the bottom UHPC reinforcement layer 2, the thickness of the bottom UHPC reinforcement layer 2 is 5-10cm.
[0047] Furthermore, to ensure the reinforcement effect at the bottom of the concrete box arch and the column positions, and to reasonably control the weight of the top UHPC reinforcement layer 3, the thickness of the top UHPC reinforcement layer at the connection point 301 between the top UHPC reinforcement layer and the column on the arch exceeds the maximum height of the top longitudinal reinforcing steel bar 6 by 3-5 cm, while the thickness of the top UHPC reinforcement layer 3 at other locations is 5-10 cm. In addition, the thickness at the arch foot can also be appropriately increased.
[0048] The main construction steps for reinforcing the large-span box arch bridges described above using UHPC are as follows:
[0049] (1) Roughen the bottom surface of the original concrete box arch 1, drill holes to insert bottom shear reinforcement bars, tie bottom longitudinal reinforcement bars 7, support the formwork with a hanger, and pour the bottom UHPC reinforcement layer 2 symmetrically and orderly from the arch foot to the arch top.
[0050] (2) After the bottom UHPC reinforcement layer 2 is strengthened, the original arch fill material is first removed. Then, the top surface of the concrete box arch 1 is roughened, holes are drilled and top shear reinforcement bars are inserted, the longitudinal reinforcing bars 6 are tied, the side formwork is supported, and the top UHPC reinforcement layer 3 is poured symmetrically and orderly from the arch foot to the arch top. The phased pouring of the bottom UHPC reinforcement layer 2 and the top UHPC reinforcement layer 3 helps to reduce the self-weight of the reinforcement, reduce construction risks, and minimize the impact of the reinforcement weight on the arch rib shape. In addition, the self-weight of the top UHPC reinforcement layer 3 is borne by the original structure + the bottom UHPC reinforcement layer 2, which improves the utilization efficiency of the bottom UHPC reinforcement layer 2.
[0051] (3) After the UHPC reinforcement layer 2 is strengthened, the arch filler 5 and the bridge deck system are redone.
Claims
1. A large-span box arch bridge reinforced with UHPC, comprising the original concrete box arch and columns on the arch, characterized in that... Also includes: The bottom shear reinforcement is inserted at intervals into the bottom surface of the original concrete box arch. The longitudinal reinforcing bars at the bottom surface are spaced longitudinally on the bottom surface of the original concrete box arch and are connected and fixed to the bottom shear bars. The bottom UHPC reinforcement layer is set on the bottom surface of the original concrete box arch, covering the bottom shear reinforcement and the bottom longitudinal reinforcing steel. Top surface shear reinforcement bars are inserted at intervals into the top surface of the original concrete box arch; The top longitudinal reinforcing bars are longitudinally spaced on the top surface of the original concrete box arch and are connected and fixed to the top shear bars. They include a first top longitudinal reinforcing bar and a second top longitudinal reinforcing bar. The first and second top longitudinal reinforcing bars are alternately and equidistantly arranged. At the connection position between the original concrete box arch and the arch column, the first top longitudinal reinforcing bar extends beyond the top surface of the original concrete box arch by a distance d1 and passes through the arch column. The second top longitudinal reinforcing bar extends beyond the top surface of the original concrete box arch by a distance d2 and passes through the arch column. d1 and d2 are not equal. The top surface UHPC reinforcement layer is set on the top surface of the original concrete box arch, covering the top surface shear reinforcement and the top surface longitudinal reinforcing steel.
2. The large-span box arch bridge reinforced with UHPC according to claim 1, characterized in that: The bottom longitudinal reinforcing bars include a first bottom longitudinal reinforcing bar and a second bottom longitudinal reinforcing bar. The first bottom longitudinal reinforcing bar and the second bottom longitudinal reinforcing bar are arranged alternately at equal intervals. At the connection position between the original concrete box arch and the arch seat, the first bottom longitudinal reinforcing bar and the second bottom longitudinal reinforcing bar are inserted into the arch seat at different height positions. A connecting base is provided on the outside of the arch seat. The connecting base is connected to the bottom UHPC reinforcement layer and covers the first bottom longitudinal reinforcing steel bar and the second bottom longitudinal reinforcing steel bar.
3. The large-span box arch bridge reinforced with UHPC according to claim 1, characterized in that: The original concrete box arch, bridge deck, and the space between the two arch columns in the middle are also filled with arch filler.
4. The large-span box arch bridge reinforced with UHPC according to claim 1, characterized in that: The spacing between the bottom shear bars and the top shear bars is 0.4-0.5m, and they are arranged in a quincunx pattern.
5. The large-span box arch bridge reinforced with UHPC according to claim 1, characterized in that: It also includes bottom transverse reinforcing bars, which are arranged at transverse intervals on the bottom surface of the original concrete box arch. The diameter of the bottom transverse reinforcing bars is no more than 16mm, and the spacing between the bottom transverse reinforcing bars is 10-15cm.
6. The large-span box arch bridge reinforced with UHPC according to claim 1, characterized in that: It also includes transverse reinforcing bars on the top surface, which are arranged at transverse intervals on the top surface of the original concrete box arch. The diameter of the transverse reinforcing bars on the top surface is no more than 16mm, and the spacing between the transverse reinforcing bars on the top surface is 10-15cm.
7. The large-span box arch bridge reinforced with UHPC according to claim 1, characterized in that: The diameter of the bottom longitudinal reinforcing bars is no greater than 16mm, and the spacing between the bottom longitudinal reinforcing bars is 10-15cm; the diameter of the top longitudinal reinforcing bars is no greater than 16mm, and the spacing between the top longitudinal reinforcing bars is 10-15cm.
8. The large-span box arch bridge reinforced with UHPC according to claim 1, characterized in that: d1 is 10-15cm; d2 is greater than d1, which is 10-15cm.
9. The large-span box arch bridge reinforced with UHPC according to claim 1, characterized in that: The thickness of the bottom UHPC reinforcement layer is 5-10cm.
10. The large-span box arch bridge reinforced with UHPC according to any one of claims 1-9, characterized in that: At the connection point between the top UHPC reinforcement layer and the arch column, the thickness exceeds the maximum height of the longitudinal reinforcing steel bars on the top surface by 3-5 cm, while the thickness of the top UHPC reinforcement layer at other locations is 5-10 cm.