A lightweight arch-building system suitable for large-span cantilever cast-in-place arch bridges

Abstract

The present invention relates to the field of reinforced concrete arch bridges, and in particular to a lightweight arch building system suitable for large-span cantilever cast arch bridges; wherein the bridge deck beam comprises a composite bridge deck and a plurality of I-beams, the I-beams being used to support the composite bridge deck; the composite bridge deck comprises a steel bottom plate and concrete, the steel bottom plate being laid above the I-beams, and concrete being arranged on the steel bottom plate; the arch building system comprises a steel inner shell composite structure thin-walled box-type column, a prestressed cap beam and the above-mentioned bridge deck beam, the lower part of the prestressed cap beam being fixedly connected to the column, and the upper part of the prestressed cap beam receiving the bridge deck beam, so that the overall structure of the arch building system is lightweight and the span is further developed.

Description

Technical Field

[0001] The invention relates to the field of reinforced concrete arch bridges, in particular to a lightweight arch construction system suitable for large-span cantilever cast arch bridges. Background Art

[0002] The cantilever casting method for domestic arch bridges began to be used and developed at the beginning of this century, when the main span of the 150-meter Baishagou No. 1 Bridge on the Xichang-Panzhihua Expressway in Sichuan Province was built. At present, most of the cantilever casting arch bridges built in China are about 200 meters, and the span breakthrough has not been significant so far. In addition to the large size of the arch ring section itself, the heavy weight of the arch structure (arch rib superstructure) is also a factor that limits the further increase of the span. The arch structure of the arch bridge mainly includes columns, cap beams and bridge deck beams. Among them, the columns on the arch usually adopt reinforced concrete box structure with heavy self-weight. In large-span arch bridges, in order to reduce the deadweight, a number of hollow box chambers are often set inside the high columns. The box chambers are horizontally partitioned by partitions, and manholes are reserved in the middle of the partitions. The cap beam usually adopts a rectangular cross-section and ordinary reinforced concrete structure with a large cross-sectional size and heavy self-weight. At the same time, the upper structure bridge deck beams are mostly in the form of prefabricated small box beams, prefabricated hollow slabs and prefabricated T-beams. The use of concrete bridge deck beams has the disadvantages of heavy self-weight and difficulty in lifting, which affects the further increase of the main arch span. Summary of the invention

[0003] The purpose of the present invention is to provide a lightweight arch building system suitable for large-span cantilever cast arch bridges, which can achieve lightweight structure, in order to solve the problem that the weight of the arch building in the prior art affects the further increase of the main arch span.

[0004] In order to achieve the above object, the technical solution adopted by the present invention is:

[0005] A bridge deck beam suitable for a large-span cantilever cast-concrete arch bridge comprises a composite bridge deck and a plurality of I-beams, wherein the I-beams are used to support the composite bridge deck; the composite bridge deck comprises a steel bottom plate and concrete, wherein the steel bottom plate is laid above the I-beams and concrete is arranged on the steel bottom plate.

[0006] The present invention adopts I-beam and steel-concrete composite bridge deck technology, which has a simple structure, is easy to erect, easy to maintain, and has good durability. It reduces the amount of concrete pouring for the bridge deck beam. The weight and lifting weight of the 30-meter span steel-concrete composite beam are reduced by nearly 30% compared with the traditional T-beam, which can reduce the project cost and has outstanding application advantages in lightweight arch bridge deck beams.

[0007] As a preferred solution of the present invention, each I-beam is arranged vertically, and the length direction of each I-beam extends in the same direction (that is, each I-beam is parallel to each other); two adjacent I-beams are connected by a cross partition, which is beneficial to enhancing the overall stability and pressure-bearing capacity of the bridge deck structure.

[0008] As a preferred solution of the present invention, the I-beams are distributed along the transverse direction of the composite bridge deck, that is, the length extension direction of each I-beam is arranged along the longitudinal direction of the bridge, which is convenient for construction.

[0009] As a preferred solution of the present invention, the steel bottom plate is wavy, and the length direction of the wavy shape is arranged along the distribution direction of the I-beam. The wavy shape is conducive to the adhesion of filling concrete, and also reduces the amount of concrete pouring, making the structure lighter; at the same time, the length direction of the wavy shape is arranged along the distribution direction of the I-beam, so that there are more points of force between the steel bottom plate and the I-beam, and the force-bearing performance of the steel bottom plate is better.

[0010] As a preferred solution of the present invention, the steel bottom plate includes several blocks, each of which connects two adjacent I-beams, and a gap is left laterally between adjacent steel bottom plates for concrete filling, which is beneficial to strengthen the connection between the bridge deck and the I-beam.

[0011] As a preferred solution of the present invention, the concrete is C50 steel fiber concrete with a thickness of 14 to 17 cm, so that the bridge deck has high strength and high performance and the structure is lightweight.

[0012] Based on the above-mentioned bridge deck beam structure, the present invention provides an arch building system suitable for a large-span cantilever cast-concrete arch bridge, comprising columns, prestressed cap beams and the above-mentioned bridge deck beams. The lower part of the prestressed cap beam is fixedly connected to the columns, and the upper part of the prestressed cap beam supports the bridge deck beam, so that the overall structure of the arch building system is lightweight and the span is further expanded.

[0013] As a preferred solution of the present invention, the column is a reinforced concrete box-type structure, and a steel inner shell is provided inside the column. The provision of the steel inner shell increases the crack resistance of the concrete and the torsional rigidity of the cross section. On the premise of ensuring the pressure bearing capacity of the column, the partition can be further avoided inside the column, and the wall thickness of the column box chamber can be reduced; at the same time, the steel inner shell can be used as an inner mold for the column concrete construction, and does not need to be removed after forming, which is convenient for construction and realizes lightweight structure and construction.

[0014] As a preferred solution of the present invention, the steel inner shell is connected to the column concrete through shear nails, thereby strengthening the connection between the steel inner shell and the column and improving the structural strength.

[0015] As a preferred solution of the present invention, the steel inner shell is provided with a chamfer, which can effectively reduce the local stress of the chamfer.

[0016] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0017] 1. The present invention adopts I-beam and corrugated steel-concrete composite bridge deck technology, which is easy to erect, easy to maintain, durable, and can reduce the project cost. The weight and lifting weight of the 30-meter span steel-concrete composite beam are reduced by nearly 30% compared with the traditional T-beam, and the application advantage of lightweight arch bridge deck beams is outstanding.

[0018] 2. The present invention adopts a thin-walled box-type column with a steel inner shell composite structure, which can effectively reduce the structural deadweight of the high column, and can reduce the weight by about 28% compared with conventional reinforced concrete box-type high columns. The steel inner shell not only increases the crack resistance of the concrete and the torsional rigidity of the cross section, avoids the need to set a partition in the column, but also reduces the wall thickness of the column box chamber. At the same time, it can be used as an inner mold for the construction of the column concrete. After forming, it does not need to be removed, which is convenient for construction and realizes lightweight structure and construction.

[0019] 3. The present invention adopts a prestressed cap beam, which can greatly reduce the cross-sectional size of the cap beam and reduce the amount of concrete material, reducing concrete by about 35%. At the same time, the positive and negative bending moment reinforcements are matched as much as possible to reduce the amount of ordinary steel bars. The lightweight prestressed cap beam reduces the concentrated force transmitted from the column to the arch ring, which can further increase the span of the main arch. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the cross-sectional structure of the bridge deck beam.

[0021] Figure 2 yes Figure 1 Schematic diagram of the cross-sectional structure along the AA axis.

[0022] Figure 3 yes Figure 2 Schematic diagram of the cross-sectional structure along the BB axis.

[0023] Figure 4 yes Figure 1 Enlarged view of part I in the middle.

[0024] Figure 5 It is a schematic diagram of the longitudinal section of the composite bridge deck.

[0025] Figure 6 It is a structural diagram of the corrugated steel base plate.

[0026] Figure 7 It is a schematic elevation diagram of the arch building system.

[0027] Figure 8 yes Figure 7 Schematic diagram of the CC section structure (bridge deck beam omitted).

[0028] Fig. 9 yes Figure 8 Schematic diagram of the side structure.

[0029] Fig.10 yes Figure 8 Schematic diagram of the cross-section structure in the middle DD direction.

[0030] Icons: 1-bridge deck beam; 11-I-beam; 12-composite bridge deck; 121-steel base plate; 122-C50 steel fiber concrete; 13-diaphragm; 2-prestressed cap beam; 3-column; 31-steel inner shell; 32-shear studs; 33-chamfer. DETAILED DESCRIPTION

[0031] The present invention will be described in detail below in conjunction with the accompanying drawings.

[0032] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0033] Example 1

[0034] A bridge deck beam 1 suitable for a large-span cantilever cast concrete arch bridge, such as Figure 1-Figure 6 , using steel-concrete composite beams, including a composite bridge deck 12 and several I-beams 11. The upper part of the I-beam 11 is fixedly connected to the composite bridge deck 12, and the I-beam 11 plays a supporting role; the composite bridge deck 12 includes a steel bottom plate 121 and concrete 122. The steel bottom plate 121 is laid on the top of the I-beam 11, and 14-17cm thick C50 steel fiber concrete 122 is cast on the steel bottom plate 121. Among them, the I-beam 11 is prefabricated with C50 concrete and is 1.8m high; the steel bottom plate 121 is 1cm thick, the cast-in-place composite bridge deck 12 is 0.18m high, and the total height of the bridge deck beam 1 is 1.98m. The surface of the composite bridge deck 12 can be further paved with 7cm thick asphalt concrete 122, and guardrails are set on both sides.

[0035] Specifically, Figure 1 , 2 Each I-beam 11 is arranged vertically, and the length direction of each I-beam 11 extends along the longitudinal direction of the bridge deck beam 1, that is, the I-beam 11 is distributed transversely; two adjacent I-beams 11 are transversely connected by a diaphragm 13, which is conducive to strengthening the overall stability and pressure bearing capacity of the bridge deck structure. Each I-beam 11 can be an integral prefabricated structure, or it can be composed of several I-beam unit segments according to the design size of the bridge deck beam during construction ( Figure 3 Only a small section of the bridge deck beam is marked to illustrate the side structure) to facilitate construction.

[0036] like Figure 5 , 6The steel bottom plate 121 is wavy in shape, which is conducive to the adhesion of filling concrete and reduces the amount of concrete pouring, making the structure lighter. At the same time, the length direction of the wavy shape is arranged along the distribution direction (i.e., the horizontal direction) of the I-beam 11, so that there are more fulcrums between the steel bottom plate 121 and the I-beam 11, and the force-bearing performance of the steel bottom plate 121 is better.

[0037] like Figure 4 The steel bottom plate 121 includes several blocks, each of which connects two adjacent I-beams 11, and a gap is left laterally between adjacent steel bottom plates 121 for concrete filling, which is beneficial to strengthen the connection between the bridge deck and the I-beam 11.

[0038] The I-beam and steel-concrete composite bridge deck technology are simple in structure, easy to erect, easy to maintain, and have good durability. The amount of concrete pouring for the bridge deck beam is reduced, and the weight and lifting weight of the 30-meter span steel-concrete composite beam are reduced by nearly 30% compared to traditional T-beams, which can reduce the project cost. It has outstanding application advantages in lightweight arch bridge deck beams.

[0039] Example 2

[0040] Based on Example 1, this embodiment provides an arch building system suitable for a large-span cantilever cast concrete arch bridge, such as Figure 7-10 , including columns 3, T-section prestressed cap beam 2 and the above-mentioned bridge deck beam 1. The lower part of the prestressed cap beam 2 is fixedly connected to the column 3, and the upper part of the prestressed cap beam 2 supports the bridge deck beam 1, so that the overall structure of the arch building system is lightweight and the span is further developed.

[0041] Among them, Fig. 9 The prestressed cap beam 2 is designed as a concrete T-section. It is designed according to the full prestress control, and the positive and negative bending moments are controlled as close as possible. The configuration of the prestressed steel strands is reasonably controlled according to the stress requirements of the construction and operation stages to determine the optimal cross-sectional size to achieve the lightest cap beam weight and realize lightweight structure.

[0042] As the span of a cantilever cast concrete arch bridge increases, the height of the arch column also needs to be increased. In this embodiment, in order to adapt the high column to the long-span arch bridge structure, for high columns with a height of more than 40m, a steel inner shell composite structure thin-walled box column is used, that is, the column 3 is designed as a reinforced concrete box structure, such as Figure 8 , Fig.10, a thin-walled steel inner shell 31 is provided inside the column 3 box, and the steel inner shell 31 can be connected to the column 3 concrete 122 through shear nails 32. Among them, the steel inner shell 31 is 8mm-10mm thick, and the column 3 box wall is 30mm thick; the steel inner shell 31 is provided with a chamfer 33 of 30cm (width) × 30cm (height), which can effectively reduce the local stress of the chamfer 33. The setting of the steel inner shell not only increases the crack resistance of the concrete, increases the torsional rigidity of the section, reduces the wall thickness of the box, avoids the setting of partitions in the column, and reduces the pouring weight of the column concrete; at the same time, the steel inner shell can be used as an inner mold for the construction of the column concrete, and does not need to be taken out after forming, which is convenient for construction, and further realizes the lightweight structure and construction.

[0043] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. An arch building system suitable for large-span cantilever cast concrete arch bridges, characterized in that: It comprises a column (3), a prestressed cap beam (2) and a bridge deck beam (1); The bridge deck beam (1) comprises a combined bridge deck (12) and a plurality of I-shaped beams (11), each of the I-shaped beams (11) being arranged vertically, and the length direction of each of the I-shaped beams (11) extending in the same direction, the plurality of I-shaped beams (11) being distributed along the transverse direction of the combined bridge deck (12), and the I-shaped beams (11) being used to support the combined bridge deck (12); the combined bridge deck (12) comprises a steel bottom plate (121) and concrete, the steel bottom plate (121) being laid on The concrete is provided above the I-beam (11) and above the steel bottom plate (121); the steel bottom plate (121) is wavy in shape, and the length direction of the wavy shape is arranged along the distribution direction of the I-beam (11); the steel bottom plate (121) comprises a plurality of pieces, each of the steel bottom plates (121) is transversely connected to two adjacent I-beams (11), and a gap is left between two adjacent steel bottom plates (121) in the transverse direction at the I-beam (11), and the gap is filled with the concrete; The lower part of the prestressed cap beam (2) is fixedly connected to the column (3), and the upper part of the prestressed cap beam (2) supports the bridge deck beam (1).

2. The arch building system suitable for large-span cantilever cast concrete arch bridge according to claim 1, characterized in that: The column (3) is a reinforced concrete box-shaped structure, and a steel inner shell (31) is provided inside the column (3).

3. The arch building system suitable for large-span cantilever cast concrete arch bridge according to claim 2, characterized in that: The steel inner shell (31) is connected to the column concrete via shear nails (32).

4. The arch building system suitable for a large-span cantilever cast concrete arch bridge according to claim 2, characterized in that: The steel inner shell (31) is provided with a chamfer (33).

5. The arch building system suitable for large-span cantilever cast concrete arch bridge according to claim 1, characterized in that: Two adjacent I-shaped beams (11) are connected via a transverse partition (13).

6. The arch building system suitable for large-span cantilever cast concrete arch bridge according to claim 1, characterized in that: The concrete is C50 steel fiber concrete (122) with a thickness of 14 to 17 cm.

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