An eccentric bridge structure using an asymmetric cover beam

Abstract

The utility model discloses an eccentric bridge structure adopting asymmetric bent cap belongs to bridge structure system technical field, including pile foundation, the fixed bearing platform of pile foundation top, the fixed pier of bearing platform top, the asymmetric bent cap of fixed steel of pier top, asymmetric bent cap includes bent cap main part, and bent cap main part divides into counterweight part, connecting portion, overhanging part, and connecting portion is fixedly connected with pier top, and connecting portion is center, and counterweight part and overhanging part are asymmetric, overhanging part is variable cross section structure, and cross section gradually becomes small from the end of immediately adjacent pier, counterweight part and connecting portion, and the cross section of the end of immediately adjacent pier of overhanging part is same, and several counterweight steel sheets are assembled on counterweight part. Through the connection of several counterweight steel sheets on counterweight part, the reverse force is set in the reverse direction of overhanging part, and is used for balancing eccentric bending moment that overhanging part transmits to lower structure, solve the technical problem of long construction period of pre-stress complex when using cast-in-place bent cap in prior art.

Description

Technical Field

[0001] This utility model belongs to the technical field of bridge structure systems, specifically relating to an eccentric bridge structure using an asymmetrical cap beam. Background Technology

[0002] The statements in this section are merely background information related to this utility model and do not necessarily constitute prior art.

[0003] The arrangement of piers for elevated bridges must consider not only the needs of the elevated bridge itself, but also the clearance of the road below and the overall landscape requirements. When the centerline of the elevated bridge does not coincide with the centerline of the median strip of the road below, or when the pier layout is restricted by waterways, subways, pipelines, etc., using laterally eccentric piers is an effective solution.

[0004] While a lateral eccentric arrangement can save space below, the cantilever beams of the piers and the bridge deck facilities supported by these beams impose a significant additional bending moment on the piers, resulting in a state of high eccentric stress. Furthermore, asymmetrical traffic flow exacerbates this eccentric stress state.

[0005] When a bridge pier is under large eccentric loading, firstly, due to the large eccentricity, the stress distribution across the pier section is extremely uneven, leading to localized stress concentrations that may cause material crushing or cracking. Secondly, the bending moment effect is significant, weakening the pier's bending resistance. The neutral axis shift reduces the area of ​​the compression zone, increasing the risk of bending failure and thus decreasing overall stability, potentially leading to lateral deformation or even instability. Finally, stress concentration and uneven distribution exacerbate fatigue damage to the material, especially under cyclic loading, making cracks more likely and increasing the risk of steel reinforcement corrosion, further weakening the pier's load-bearing capacity and durability. The foundation is also affected by eccentric loading, leading to uneven settlement and the risk of overturning.

[0006] The prior art discloses a design for a transversely eccentric bridge pier, which adopts an eccentric bridge pier and an irregularly shaped cross section for the cap beam. In order to cope with the eccentric bending moment generated by the eccentric pressure state, both the bridge pier and the upper cap beam are made of Class A prestressed concrete components, and the prestressing adopts low-relaxation high-strength steel strands.

[0007] Although the above scheme resists the eccentric bending moment generated at the cantilever end by applying prestress, it has the following drawbacks: the cap beam is made of concrete, which has the disadvantages of slow construction and heavy self-weight. Furthermore, the prestressing tensioning needs to be carried out after the concrete pouring is completed, which makes the prestressing application complex and the construction period long, further extending the construction period. Utility Model Content

[0008] In view of this, the purpose of this utility model is to provide an eccentric bridge structure with an asymmetrical cap beam, which can solve the technical problems of slow construction and heavy weight of the cap beam in the prior art.

[0009] To achieve the above objectives, the present invention adopts the following technical solution: An eccentric bridge structure with an asymmetric cap beam is provided, including a pile foundation, a pile cap fixed on top of the pile foundation, a bridge pier fixed on top of the pile cap, and a steel asymmetric cap beam fixed on top of the bridge pier. The asymmetric cap beam includes the main body of the cap beam, which is divided into a counterweight part, a connecting part, and a cantilever part. The connecting part is fixedly connected to the top of the pier. With the connecting part as the center, the counterweight part and the cantilever part are asymmetric. The cantilever section is a variable cross-section structure, with the cross-section gradually decreasing from the end immediately adjacent to the pier. The counterweight section has the same cross-section as the connecting section and the end of the cantilever section adjacent to the pier, and the counterweight section is equipped with several counterweight steel plates.

[0010] Preferably, the main body of the cap beam is made of H-beams, including a web and fixed flanges at the upper and lower ends of the web.

[0011] Preferably, the cantilever section is located on both sides of the web plate, and multiple stiffening plates are fixed along the length of the cantilever section. The stiffening plates are fixedly connected to the web plate and the flange plate.

[0012] Preferably, the lower end flange of the connecting part has multiple first bolt holes evenly opened on both sides of the web, and the first bolts are pre-embedded at the corresponding positions on the top of the pier. The first bolts pass through the corresponding first bolt holes and are connected to the first nuts to fix the connecting part to the pier.

[0013] Preferably, the bridge piers are made of steel-concrete composite structures and are cast together with the abutment.

[0014] Preferably, an embedded plate is fixed to one end of the first bolt, and the embedded plate and part of the bolt of the first bolt are cast into the top concrete of the pier.

[0015] Preferably, the upper and lower wing plates of the counterweight have second bolt holes on both sides of the web, and the counterweight steel plate has a third bolt hole. After the second bolt hole and the third bolt hole are aligned, the second bolt passes through, and the second nut is threaded to both ends of the second bolt.

[0016] Preferably, the top of the connecting part and the cantilever part are fixed with at least two supports; between the two piers, the top surfaces of the supports are on the same plane, and the two ends of the bridge superstructure are installed on the top of the supports.

[0017] Preferably, the counterweight steel plates are assembled in two stages, one after the asymmetric cap beam is installed and the other after the bridge superstructure is installed.

[0018] Preferably, multiple pile foundations are evenly fixed at the bottom of the pier cap, and the center of the top of the pier cap is concentric with the center of the pier.

[0019] Compared with the prior art, the advantages and positive effects of this utility model are: This invention employs an asymmetrical steel cap beam connected to the bridge pier. By connecting several counterweight steel plates to the counterweight section, different magnitudes of counterforce can be applied in the opposite direction of the cantilever section to balance the eccentric bending moment transmitted from the cantilever section to the substructure. This solves the technical problems of complex prestressing and long construction period in existing technologies using cast-in-place cap beams. It has the advantages of convenient construction and fast construction speed. Attached Figure Description

[0020] The accompanying drawings, which form part of this specification, are used to provide a further understanding of this utility model. The illustrative embodiments of this utility model and their descriptions are used to explain this utility model and do not constitute an improper limitation of this utility model.

[0021] Figure 1 This is a three-dimensional schematic diagram of an eccentric bridge structure with an asymmetric cap beam according to an embodiment of the present invention; Figure 2 This is a side view of an eccentric bridge structure with an asymmetrical cap beam according to an embodiment of the present invention; Figure 3 This is a three-dimensional schematic diagram of the connection between the asymmetric cap beam and the bridge pier according to an embodiment of this utility model; Figure 4 This is a three-dimensional schematic diagram of the main body of the cap beam according to an embodiment of the present utility model; Figure 5 This is a three-dimensional schematic diagram of the first bolt in an embodiment of this utility model; Figure 6 This is a three-dimensional schematic diagram of the counterweight steel plate according to an embodiment of the present utility model; Figure 7 This is a three-dimensional schematic diagram of the second bolt according to an embodiment of the present invention; In the picture: 1. Pile foundation; 2. Pier cap; 3. Pier; 4. Asymmetric cap beam; 41. Cap beam body; 411. Stiffening plate; 412. First bolt hole; 413. Second bolt hole; 42. First bolt; 421. Embedded plate; 422. First threaded rod; 423. First nut; 43. Counterweight steel plate; 431. Third bolt hole; 44. Second bolt; 441. Second nut; 442. Second threaded rod; 45. Support; 46. Connection part; 47. Cantilever part; 48. Counterweight part; 5. Bridge superstructure. Detailed Implementation

[0022] It should be noted that the following detailed description is illustrative and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0023] The present invention will now be described in detail with reference to the accompanying drawings.

[0024] This embodiment discloses an eccentric bridge structure employing an asymmetric cap beam, such as... Figure 1 As shown, the structure includes a pile foundation 1, a pile cap 2 fixed to the top of the pile foundation 1, a bridge pier 3 fixed to the top of the pile cap 2, and a steel asymmetric cap beam 4 fixed to the top of the bridge pier 3; the two ends of the bridge superstructure 5 are installed on the top of the asymmetric cap beam 4 of the two bridge piers 3.

[0025] like Figure 2 As shown, the asymmetrical cap beam 4 includes a cap beam body 41, which is divided into a counterweight part 48, a connecting part 46, and a cantilever part 47. The connecting part 46 is fixedly connected to the top of the pier 3. With the connecting part 46 as the center, the counterweight part 48 and the cantilever part 47 are asymmetrical. It should be noted that the counterweight part 48, the connecting part 46, and the cantilever part 47 are manufactured as a single piece.

[0026] like Figure 2 As shown, the cantilever section 47 is a variable cross-section structure. Starting from the end adjacent to the pier 3, the cross-section of the cantilever section 47 gradually decreases. The purpose of this design is that the gradually decreasing cross-section is conducive to the cantilever arrangement, and the weight of the cantilever section 47 is reduced while ensuring rigidity.

[0027] like Figure 2 , Figure 3 As shown, the counterweight part 48 has the same cross-section as the connecting part 46 and the end of the cantilever part 47 adjacent to the pier. Several counterweight steel plates 43 are mounted on the counterweight part 48. It should be noted that by configuring different numbers and sizes of counterweight steel plates 43 on the counterweight part 48, different magnitudes of reverse forces can be set in the opposite direction of the cantilever part 47 of the asymmetric cap beam 4 to balance the eccentric bending moment transmitted by the cantilever part 47 to the substructure (i.e., pier 3, abutment 2, and pile foundation 1).

[0028] It is understandable that the length of the counterweight 48 is shorter than that of the cantilever 47, since the cantilever 47 plays a major supporting role for the superstructure of the bridge.

[0029] like Figure 3 , Figure 4 As shown, the main body 41 of the cap beam is made of H-beams, including a web and fixed flanges at the upper and lower ends of the web. Using H-beams as the main body 41 of the cap beam can provide supporting rigidity, reduce self-weight compared to concrete structures, and, more importantly, facilitate the installation of several counterweight steel plates 43 on the counterweight part 48.

[0030] like Figure 3 , Figure 4 As shown, multiple stiffening plates 411 are fixed on both sides of the web of the cantilever section 47 along its length. The stiffening plates 411 are fixedly connected to the web and flanges. It can be understood that fixing multiple stiffening plates 411 on both sides of the web of the cantilever section 47 can further increase the rigidity of the H-beam cap beam 41 and ensure support for the bridge superstructure 5.

[0031] like Figure 3 , Figure 4 As shown, the lower end wing plate of the connecting part 46 has multiple first bolt holes 412 evenly opened on both sides of the web plate. At the same time, multiple first bolts 42 are pre-embedded at the corresponding positions on the top of the pier 3. The first bolts 42 pass through the corresponding first bolt holes 412 and are connected to the first nuts 423, thereby fixing the connecting part 46 to the top of the pier 3.

[0032] like Figure 1 , Figure 3 As shown, in this embodiment, the pier 3 adopts a steel-concrete composite structure and is cast together with the abutment 2. Using a steel-concrete composite structure to make the pier can give full play to the advantage of the high compressive strength of the steel-concrete composite structure. The steel pipe itself is both a load-bearing structure and an external formwork, and has the advantages of industrialized rapid installation and construction, which has the advantages of convenient construction and fast construction speed. It has good ductility and good energy dissipation performance, which is beneficial to earthquake resistance.

[0033] It should be noted that since the pier 3 is a steel-concrete composite structure, bolted connections are used to speed up the connection between the connecting part 46 and the top of the pier 3, thereby accelerating the installation of the asymmetric cap beam 4, saving construction time and reducing construction costs.

[0034] like Figure 3 , Figure 5 As shown, an embedded plate 421 is fixed to one end of the first screw 422 of the first bolt 42. The embedded plate 421 and the lower half of the first screw 422 are cast and anchored in the top concrete of the pier 3. The upper half of the first screw 422 passes through the first bolt hole 412 of the cap beam body 41 and is fixed by the first nut 423. The embedded plate 421 is fixed to one end of the first screw 422, and the embedded plate 421 and the lower half of the first screw 422 are cast and anchored together in the top concrete of the pier 3. This can increase the anchoring force of the first bolt 42 in the top concrete of the pier 3, thereby enhancing the reliability of the connection between the asymmetric cap beam 4 and the pier 3.

[0035] like Figure 3 , Figure 4 , Figure 6 , Figure 7As shown, the counterweight steel plate 43 is assembled inside the counterweight part 48 by the second bolt 44. Specifically, the upper and lower wing plates of the counterweight part 48 are provided with second bolt holes 413 on both sides of the web plate, and the counterweight steel plate 43 is provided with a third bolt hole 431. The second bolt hole 413 and the third bolt hole 431 are aligned, and the second screw 442 passes through the second bolt 44. The two ends of the second screw 442 are threaded with second nuts 441 to connect the counterweight steel plate 43 to the counterweight part 48.

[0036] In this embodiment, the length of the counterweight steel plate 43 is less than the length of the counterweight part 48, and the width is less than half the width of the counterweight part 48, so that the counterweight steel plate 43 is installed inside the counterweight part 48.

[0037] like Figure 1 , Figure 2 , Figure 3 , Figure 4 As shown, supports 45 are fixedly installed at the top of the connecting part 46 and the cantilever part 47 of the asymmetrical cap beam 4. At least two supports 45 are provided, one at the top of the connecting part 46 and the other at the top of the cantilever part 47. Between the two piers 3, the top surfaces of the supports 45 are made to be on the same plane, and the two ends of the bridge superstructure 5 are installed on the top of the supports 45 of the cap beam body 41. Thus, the weight of the bridge superstructure 5 is supported on the connecting part 46 and the cantilever part 47. The weight on one side of the centerline of the bridge superstructure 5 presses down on the connecting part 46 and then is transferred downward to the pier 3; the weight on the other side presses on the cantilever part 47. Through the counterweight 48, a reaction force is generated on the load on the cantilever part 47 to balance the eccentric bending moment transmitted from the cantilever part 47 to the pier 3.

[0038] It should be noted that the counterweight steel plates 43 need to be assembled in two stages. The first assembly is after the asymmetric cap beam 4 is installed on the pier 3. A sufficient number of counterweight steel plates 43 are installed on the counterweight section 48 of the asymmetric cap beam 4 to balance the bending moment caused by the self-weight of the cantilever section 47, so that the cap beam body 41 is in a self-balancing state, ensuring that the cap beam body 41 is not deformed, and at the same time ensuring that all supports 45 are on the same horizontal plane. The counterweight steel plates 43 are then initially fixed by the second bolts 44. The second assembly is after the bridge superstructure 5 is installed. The counterweight steel plates 43 are then installed on the counterweight section 48 to balance the additional eccentric bending moment caused by the bridge superstructure 5 above the cantilever section 47.

[0039] like Figure 1 , Figure 2 As shown, multiple pile foundations 1 are evenly fixed at the bottom of the pier 2, and the center of the top of the pier 2 is concentric with the center of the pier 3, thereby ensuring that the load of the superstructure is evenly transferred downward to the pier 2 and the pile foundations 1, and ensuring the stability of the overall structure.

[0040] Working principle: Because the center of gravity of the bridge deck of the superstructure 5 and the pier 3 do not coincide, the load application point of the pier 3 deviates from its lateral center. This eccentric effect leads to a significant asymmetry in the stress distribution on both sides of the pier 3. One side may experience greater compressive stress, while the other side may experience tensile stress or less compressive stress. Local stress concentration may occur on the eccentric side, especially in the area near the eccentricity. If the material strength is insufficient, local crushing or cracking may occur, thus affecting the overall load-bearing capacity. In this embodiment, by installing a counterweight steel plate 43 on one side of the asymmetrical cap beam 4, an unbalanced gravity is created on both sides of the asymmetrical cap beam 4, generating a reverse eccentric bending moment. This balances the eccentric bending moment caused by the eccentric arrangement of the bridge superstructure 5, ensuring that the bridge pier 3, abutment 2, pile foundation 1, and other substructures are under axial stress.

[0041] In one specific implementation, the construction steps for the eccentric bridge structure using the asymmetric cap beam 4 are as follows: First, the construction of pile foundation 1 is carried out. Then, the formwork required for the construction of pile cap 2 is erected, the steel cage is tied, and the steel pipe of pier 3 is initially fixed. Next, concrete is poured into the steel pipe and formwork. During the concrete pouring process, a sufficient number of first bolts 42 are placed at the corresponding positions on the top of the pier 3, and the first bolts 422 extend out of the top surface of the steel pipe concrete pier by a sufficient length to facilitate connection with the asymmetric cap beam 4. After the concrete curing is completed, the prefabricated asymmetric cap beam 4 is hoisted, so that the reserved first screw 422 passes through the first bolt hole 412 on the cap beam body 41, and then the first nut 423 is installed for fixation; Then, a sufficient number of counterweight steel plates 43 are installed on the counterweight part 48 of the asymmetric cap beam 4 to balance the bending moment caused by the self-weight of the cantilever part 47, so that the main body 41 of the cap beam is in a self-balancing state, ensuring that the main body 41 of the cap beam 41 is not deformed, ensuring that all supports 45 are on the same horizontal plane, and the counterweight steel plates 43 are initially fixed by the second bolt 44. Then, the bridge superstructure 5 was hoisted in place. Finally, the remaining counterweight steel plates 43 are installed in the counterweight section 48 to balance the additional eccentric bending moment brought about by the bridge superstructure 5.

[0042] Although the specific embodiments of the present utility model have been described above in conjunction with the accompanying drawings, this is not intended to limit the scope of protection of the present utility model. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art without creative effort based on the technical solution of the present utility model are still within the scope of protection of the present utility model.

Claims

1. An eccentric bridge structure employing an asymmetrical cap beam, characterized in that, The structure includes a pile foundation, a pile cap fixed to the top of the pile foundation, a bridge pier fixed to the top of the pile cap, and a steel asymmetric cap beam fixed to the top of the bridge pier. The asymmetric cap beam includes a cap beam body, which is divided into a counterweight part, a connecting part, and a cantilever part. The connecting part is fixedly connected to the top of the pier. With the connecting part as the center, the counterweight part and the cantilever part are asymmetric. The cantilever section is a variable cross-section structure, with the cross-section gradually decreasing from the end immediately adjacent to the pier. The counterweight section has the same cross-section as the connecting section and the end of the cantilever section adjacent to the pier, and the counterweight section is equipped with several counterweight steel plates.

2. The eccentric bridge structure employing an asymmetric cap beam as described in claim 1, characterized in that, The main body of the cap beam is made of H-beams, including a web and fixed flanges at the upper and lower ends of the web.

3. An eccentric bridge structure employing an asymmetric cap beam as described in claim 2, characterized in that, The cantilevered portion is located on both sides of the web plate, and multiple stiffening plates are fixed along the length of the cantilevered portion. The stiffening plates are fixedly connected to the web plate and the wing plate.

4. An eccentric bridge structure employing an asymmetric cap beam as described in claim 2, characterized in that, The lower end of the connecting part, the wing plate, has multiple first bolt holes evenly opened on both sides of the web plate. The first bolt is pre-embedded at the corresponding position on the top of the pier. The first bolt passes through the corresponding first bolt hole and connects with the first nut to fix the connecting part to the pier.

5. An eccentric bridge structure employing an asymmetric cap beam as described in claim 4, characterized in that, The bridge piers are made of steel-concrete composite and are cast together with the pier cap.

6. An eccentric bridge structure employing an asymmetric cap beam as described in claim 5, characterized in that, An embedded plate is fixed to one end of the first bolt, and the embedded plate and part of the bolt of the first bolt are cast into the top concrete of the pier.

7. An eccentric bridge structure employing an asymmetric cap beam as described in claim 2, characterized in that, The upper and lower wing plates of the counterweight part have second bolt holes on both sides of the web plate, and the counterweight steel plate has a third bolt hole. After the second bolt hole and the third bolt hole are aligned, the second bolt passes through, and the second nut is threaded to both ends of the second bolt.

8. An eccentric bridge structure employing an asymmetric cap beam as described in claim 1, characterized in that, The top fixed supports of the connecting part and the cantilever part are provided, and at least two supports are provided; between the two piers, the top surfaces of the supports are made to be on the same plane, and the two ends of the bridge superstructure are installed on the top of the supports.

9. An eccentric bridge structure employing an asymmetric cap beam as described in claim 8, characterized in that, The counterweight steel plates are assembled in two stages, one after the asymmetric cap beam is installed, and the other after the bridge superstructure is installed.

10. An eccentric bridge structure employing an asymmetric cap beam as described in claim 1, characterized in that, Multiple pile foundations are evenly fixed at the bottom of the pier, and the center of the top of the pier is concentric with the center of the bridge pier.

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