Structure for changing existing railroad bridge into rigid roadbed and construction method

Abstract

The invention relates to a structure for changing an existing railway bridge into a rigid roadbed and a construction method. The structure comprises a pile foundation, a bearing platform, a bearing platform top retaining wall and a filling steel plate. The pile foundation and the bearing platform are located below an existing bridge girder, the existing bridge girder is separated from an original support after being lifted, and a filling steel plate is inserted between the bottom of the existing bridge girder and the bearing platform. The bearing platform top retaining walls are located on the two transverse sides of the existing bridge girder and located on the top of the bearing platform, and early-strength micro-expansion concrete is poured on the upper portion of the bearing platform, the inner sides of the bearing platform top retaining walls and the lower portion of the existing bridge girder. Two structures of a bridge and a roadbed are reasonably fused, the structure is novel and reasonable in stress, the improved structure has good overall performance and can better adapt to the stress and deformation requirements of a turnout structure, the purpose of inserting a turnout into an existing railway road-bridge transition area can be achieved under the condition that railway operation is not interrupted, and the construction period is shortened. The influence of the existing railway wiring reconstruction project on traffic operation is greatly reduced, and the construction period is shortened.

Description

Technical Field

[0001] The invention relates to the technical field of bridge construction, and in particular to a structure and construction method for converting an existing railway bridge into a rigid roadbed. Background Art

[0002] A railway switch area is a specific area on a railway line, which includes turnouts and related track circuit equipment. Among them, the turnout is the core component of the railway switch area and is a line connection device that allows locomotives and vehicles to transfer from one track to another.

[0003] According to the technical requirements of the railway turnout area, the turnout cannot be set up in the road-bridge transition zone. However, the existing railway connection project often requires the insertion of turnouts in the road-bridge transition zone. According to previous transformation experience, it is necessary to interrupt the operation of the existing railway, dismantle the existing bridges within the influence range of the turnout, and then rebuild them into roadbed projects, and then insert turnouts to resume line operations. Such a transformation project not only has a long construction period and high construction cost, but also requires the interruption of the existing railway operation, seriously affecting traffic and travel, and has a large negative social impact.

[0004] Therefore, it is necessary to propose new measures to overcome the above-mentioned defects. Summary of the invention

[0005] The purpose of the present invention is to provide a structure and construction method for converting an existing railway bridge into a rigid roadbed, so as to solve the problems of long construction period, high cost and interruption of existing railway operation when inserting a turnout in the road-bridge transition zone of an existing railway connection project.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is:

[0007] The structure of converting an existing railway bridge into a rigid roadbed includes a pile foundation, a cap, a retaining wall on the top of the cap, and a filling steel plate;

[0008] The pile foundation and the cap are located below the existing bridge main beam. The existing bridge main beam is lifted and separated from the original support, and the filling steel plate is inserted between the bottom and the cap;

[0009] The pedestal top retaining wall is located on both lateral sides of the existing bridge main beam and on the top of the pedestal. Early-strength micro-expansive concrete is poured above the pedestal, on the inner side of the pedestal top retaining wall and below the existing bridge main beam.

[0010] Furthermore, a pile side retaining wall is provided on one longitudinal side of the pile foundation.

[0011] Furthermore, there is backfilled lightweight concrete between the foundation and the ground below.

[0012] Furthermore, an embedded steel plate is provided on the top surface of the pedestal at a position corresponding to the bottom of the existing bridge main beam.

[0013] Furthermore, interconnected drainage pipes are pre-buried on both sides of the top of the early-strength slightly expansive concrete and on the top of the pedestal top retaining wall. The drainage pipes are arranged horizontally, with one end leading to the top of the existing bridge main beam and the other end leading to the outside of the pedestal top retaining wall.

[0014] Furthermore, cable troughs are pre-buried on both sides of the top of the early-strength slightly expansive concrete or on the top of the retaining wall on the top of the cap.

[0015] Furthermore, the foundation and anchoring structure of the contact network support are pre-buried on both sides of the top of the early-strength slightly expansive concrete.

[0016] On the other hand, a construction method for converting an existing railway bridge into a rigid roadbed is provided, wherein the method constructs the structure, including:

[0017] A pile foundation is constructed under the main beam of an existing bridge, and the pile foundation is arranged in multiple rows longitudinally;

[0018] Backfill the ground around the pile foundation with lightweight concrete;

[0019] A cap is constructed on the top of the pile foundation and above the backfilled lightweight concrete. A gap is left between the top surface of the cap and the bottom surface of the existing bridge main beam, and an embedded steel plate is set on the top surface of the cap;

[0020] Construct retaining walls on the top of the cap on both sides of the cap;

[0021] Deploy beam lifting equipment under the existing bridge main beam, lift the beam and release the support of the existing bridge main beam, insert a filling steel plate between the bottom of the existing bridge main beam and the embedded steel plate, and convert the existing bridge main beam to be supported by the abutment and pile foundation;

[0022] Pour early-strength slightly expansive concrete in the area enclosed by the pedestal, the retaining wall on top of the pedestal and the main beam of the existing bridge.

[0023] Furthermore, a pile foundation is constructed under the main beam of the existing bridge, including:

[0024] The pile foundation is constructed by manual digging below the ground. When the bored pile wall reaches the designed strength, steel casing is added above the ground and the bored piles are poured.

[0025] Furthermore, the early-strength slightly expansive concrete is poured in two batches. After the existing bridge main beam is converted to be supported by the pedestal and pile foundation, the phase II early-strength slightly expansive concrete is poured in the area surrounded by the pedestal, the retaining wall on the top of the pedestal and the existing bridge main beam, and then the phase III early-strength slightly expansive concrete is poured on top of the phase II early-strength slightly expansive concrete.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] The present invention provides a structure and construction method for converting an existing railway bridge into a rigid roadbed, which reasonably integrates the two structures of the bridge and the roadbed, has a novel structure, and is reasonably stressed. The structure after the transformation has good overall performance, can better adapt to the stress and deformation requirements of the turnout structure, and can complete the purpose of inserting the turnout in the existing railway bridge transition zone without interrupting the railway operation, greatly reducing the impact of the existing railway connection transformation project on traffic operations and shortening the construction period. In addition, by using the existing bridge to transform into a rigid roadbed project, the engineering waste caused by dismantling the existing bridge structure is avoided, thereby reducing the engineering cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, drawings of other embodiments can be obtained based on these drawings without paying creative work.

[0029] Figure 1 It is the elevation layout diagram of the structure of the present invention.

[0030] Figure 2 It is a cross-sectional layout diagram of the structure of the present invention.

[0031] Figure 3 It is the layout diagram of the beam bottom steel plate of the present invention.

[0032] Figure 4 It is a structural diagram of the pile side retaining wall of the present invention.

[0033] Figure 5 It is a schematic diagram of the construction method of the present invention.

[0034] The symbols in the figure are:

[0035] 1-pile foundation, 2-cap pedestal, 3-cap pedestal top retaining wall, 4-pile side retaining wall, 5-existing bridge main beam, 6-backfill lightweight concrete, 7-embedded steel plate, 8-filling steel plate, 9-stage II early-strength slightly expansive concrete, 10-stage III early-strength slightly expansive concrete, 11-railing, 12-cable trough, 13-drain pipe. DETAILED DESCRIPTION

[0036] In order to facilitate the understanding of the present invention, the present invention will be described more fully below with reference to the relevant drawings. The preferred embodiments of the present invention are given in the drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present invention more thoroughly understood.

[0037] In the description of the present invention, it is necessary to understand that the terms "upper", "lower", "longitudinal", "lateral", "top", "bottom", "inside", "outside", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0038] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "connection", "setting", etc. should be understood in a broad sense, for example, it can be fixed connection, setting, or detachable connection, setting, or integral connection, setting. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0039] It should also be noted that although the order of steps is mentioned in the method description, in some cases, they may be performed in an order different from that shown here, and this should not be construed as a limitation on the order of the steps.

[0040] In a specific implementation, the length direction of the existing bridge main beam 5, that is, the direction of the existing line, is defined as the longitudinal direction, and the direction perpendicular thereto is defined as the transverse direction.

[0041] In an existing railway connection project, if a turnout needs to be inserted in a road-bridge transition zone, it does not meet the technical requirements of the railway turnout line. Therefore, the road-bridge transition zone needs to be transformed into a rigid roadbed structure before the turnout is inserted. Aiming at such engineering requirements, the present invention provides a construction method for converting an existing railway bridge into a rigid roadbed, which does not require long-term closure of traffic on the existing line and significantly speeds up the construction speed.

[0042] like Figure 2 In some embodiments, the existing bridge main beam 5 is a T-beam structure system with two T-beam horseshoes supported by the original piers and bearings. Figure 5 The construction method of the present invention comprises the following steps:

[0043] S1: A pile foundation 1 is constructed below the 5-span main beam of an existing bridge, and the pile foundation 1 is arranged in multiple rows longitudinally.

[0044] Specifically include:

[0045] The pile foundation 1 is constructed below the ground by, but not limited to, manual digging. When the bored pile retaining wall reaches the designed strength, the next step of excavation is carried out, a steel casing is added above the ground, and bored piles are poured.

[0046] S2: Backfill the ground around pile foundation 1 with lightweight concrete.

[0047] S3: A cap 2 is constructed on the top of the pile foundation 1 and above the backfilled lightweight concrete 6 (casting of Phase I C40 concrete), leaving a gap between the top surface of the cap 2 and the bottom surface of the existing bridge main beam 5, and an embedded steel plate 7 is arranged on the top surface of the cap 2.

[0048] Specifically include:

[0049] Tie up the steel bars of the foundation 2, position the embedded steel plate 7 on the top of the foundation, and pour the foundation concrete.

[0050] The specifications of the embedded steel plate 7 can be 900mm×1300mm×10mm (along the bridge×cross the bridge×thickness), the steel plate is 10mm higher than the top surface of the cap, and the vertical clearance between the top surface of the cap steel plate and the bottom surface of the T-beam horseshoe is controlled to be 5mm. During the construction process, the vibration of the concrete between the top surface of the cap 2 and the bottom surface of the embedded steel plate 7 must be strengthened to avoid defects such as bubbles, cavities, and slurry under the embedded steel plate 7.

[0051] S4: Construct the cap top retaining wall 3 on both sides of the cap 2.

[0052] S5: Deploy beam lifting equipment under the existing bridge main beam 5, lift the beam and release the support of the existing bridge main beam 5, insert the filling steel plate 8 between the bottom of the existing bridge main beam 5 and the embedded steel plate 7, and the existing bridge main beam 5 is converted to be supported by the pedestal 2 and the pile foundation 1.

[0053] Specifically include:

[0054] Clean and wash the existing bridge main beam 5, arrange and debug the beam lifting equipment, make preparations for beam lifting, accurately measure the relative height difference δ between the beam bottom and the top surface of the embedded steel plate 7 during the skylight point, lift the beam but not limited to 5mm, release the support of the existing bridge main beam 5, insert the filling steel plate 8 on the top surface of the embedded steel plate 7, drop the beam, complete the force system conversion, and effectively transfer the upper load to the pedestal 2 and the pile foundation 1. The beam lifting equipment in this method can use a synchronous jack.

[0055] The specifications of the filling steel plate 8 are 700mm×1100mm×(δ+3)mm (along the bridge direction×transverse bridge direction×thickness), and the positioning is precise.

[0056] S6: Pour early-strength slightly expansive concrete in the area enclosed by the cap 2, the retaining wall on top of the cap 3, and the main beam 5 of the existing bridge.

[0057] The early strength micro-expansion concrete is poured in two batches. After the existing bridge main beam 5 is converted to be supported by the cap 2 and the pile foundation 1, the II phase early strength micro-expansion concrete 9 is poured in the area surrounded by the cap 2, the cap top retaining wall 3, and the existing bridge main beam 5, and then the III phase early strength micro-expansion concrete 10 is poured on the II phase early strength micro-expansion concrete 9. The construction method of pouring in two batches can adapt to the actual construction limitation of the short skylight point, which is generally difficult to complete the pouring at one time during the skylight point. In addition, pouring in two batches can reduce the hydration heat effect of large-volume concrete pouring.

[0058] After that, the auxiliary facilities such as the handrail 11, the cable trough 12, the drainage pipe 13 and the like are installed, and the handrail of the existing bridge angle steel bracket is removed. Some auxiliary facilities need to be pre-buried in advance during the construction process.

[0059] The method of the present invention can transform the existing bridge structure into a rigid roadbed structure without affecting the operation of the existing railway, so that the vertical stiffness of the bridge span and the abutment tends to be consistent, the turning angle of the abutment beam end is eliminated, the stiffness of the switch area is improved, the technical requirements of the switch area line are met, the driving safety and riding comfort of the high-speed railway in the switch area are guaranteed, and technical support can be provided for similar projects in the future.

[0060] The above construction method constructs a special rigid roadbed structure for an existing railway bridge, which includes a pile foundation 1, a cap 2, a cap top retaining wall 3, a pile side retaining wall 4, backfill lightweight concrete 6, embedded steel plates 7, filling steel plates 8, early-strength micro-expansive concrete, an existing bridge structure, and ancillary facilities.

[0061] Specifically, Figure 1-4 , the pile foundation 1 and the cap 2 are located below the span of the existing bridge main beam 5. The top surface of the cap 2 is provided with an embedded steel plate 7 at a position corresponding to the bottom of the existing bridge main beam 5, that is, the position corresponding to the horseshoe of the T beam, which is used to level the upper surface of the cap 2 and improve the flatness of the contact surface between the bottom of the existing bridge main beam 5 and the top of the cap 2. After the existing bridge main beam 5 is lifted, it is separated from the original support, and a filling steel plate 8 is inserted between the bottom and the embedded steel plate 7. The thickness of the filling steel plate 8 is determined according to the measured gap data between the top of the embedded steel plate 7 and the bottom of the existing bridge main beam 5 after the beam is lifted.

[0062] In addition, there is backfilled lightweight concrete 6 between the base 2 and the ground below, which is used to improve the bearing capacity of the foundation and reduce foundation settlement and deformation.

[0063] like Figure 1 and Figure 4 The pile side retaining wall 4 is located on one longitudinal side of the pile foundation 1 to resist the soil pressure on the pile side. The cap top retaining wall 3 is located on both lateral sides of the existing bridge main beam 5 and on the top of the cap 2. It can be used to resist the concrete side pressure during the concrete pouring process and can also be used to form a template for pouring concrete.

[0064] Early-strength micro-expansion concrete is poured above the pedestal 2, on the inner side of the pedestal top retaining wall 3, and below the existing bridge main beam 5, in two batches. Phase II early-strength micro-expansion concrete 9 is poured in a certain range below the existing bridge main beam 5, and is poured immediately after the force conversion, which plays a role in temporarily fixing the existing bridge main beam 5 to ensure normal operation during the construction of the train. Phase III early-strength micro-expansion concrete 10 is poured in the gap between the phase II early-strength micro-expansion concrete 9, the existing bridge main beam 5 and the pedestal top retaining wall 3, forming a rigid roadbed structure.

[0065] New auxiliary facilities are deployed in the reconstructed structure. Interconnected drainage pipes 13 are pre-buried on both sides of the top of the early-strength micro-expansion concrete and the top of the cap top retaining wall 3. The drainage pipes 13 are arranged horizontally, with one end leading to the top of the existing bridge main beam 5 and the other end leading to the outside of the cap top retaining wall 3. Cable troughs 12 are pre-buried on both sides of the top of the early-strength micro-expansion concrete or the top of the cap top retaining wall 3. The foundation and anchoring structure of the contact network support are also pre-buried on both sides of the top of the early-strength micro-expansion concrete.

[0066] The present invention provides structural rigidity by constructing a rigid roadbed under the main beam of the existing bridge, effectively reduces the deformation of the railway line switch area, and ensures driving safety and riding comfort; it realizes the insertion of switch in the existing railway road-bridge transition area without interrupting railway operation, greatly reduces the impact of the existing railway connection reconstruction project on traffic operation, and has high social benefits; it reasonably integrates the two infrastructures of bridge and roadbed, has a novel structure, and reasonable force, avoids engineering waste caused by dismantling the existing bridge structure, thereby reducing the project cost, and has obvious economic advantages.

[0067] The above specific examples are used to illustrate the present invention, which is only used to help understand the present invention and is not intended to limit the present invention. For those skilled in the art, according to the concept of the present invention, some simple deductions, modifications or substitutions can be made.

Claims

1. The structure of converting an existing railway bridge into a rigid roadbed is characterized by: The structure comprises a pile foundation (1), a capping platform (2), a retaining wall on the top of the capping platform (3), and a filling steel plate (8); The pile foundation (1) and the cap (2) are located below the existing bridge main beam (5); the existing bridge main beam (5) is lifted and separated from the original support, and the filling steel plate (8) is inserted between the bottom and the cap (2); The cap top retaining wall (3) is located on both lateral sides of the existing bridge main beam (5) and on the top of the cap (2); early-strength micro-expansive concrete is poured above the cap (2), on the inner side of the cap top retaining wall (3) and below the existing bridge main beam (5).

2. The structure of converting an existing railway bridge into a rigid roadbed according to claim 1, characterized in that: A pile side retaining wall (4) is provided on one longitudinal side of the pile foundation (1).

3. The structure of converting an existing railway bridge into a rigid roadbed according to claim 1 is characterized by: There is backfilled lightweight concrete (6) between the base (2) and the ground below.

4. The structure of converting an existing railway bridge into a rigid roadbed according to claim 1 is characterized in that: An embedded steel plate (7) is arranged at a position on the top surface of the pedestal (2) corresponding to the bottom of the existing bridge main beam (5).

5. The structure of converting an existing railway bridge into a rigid roadbed according to claim 1 is characterized in that: Drain pipes (13) that are interconnected are pre-buried on both sides of the top of the early-strength micro-expansive concrete and on the top of the cap top retaining wall (3); the drain pipes (13) are arranged transversely, with one end leading to the top of the existing bridge main beam (5) and the other end leading to the outside of the cap top retaining wall (3).

6. The structure of converting an existing railway bridge into a rigid roadbed according to claim 1, characterized in that: Cable ducts (12) are pre-buried on both sides of the top of the early-strength micro-expansion concrete or on the top of the cap top retaining wall (3).

7. The structure of converting an existing railway bridge into a rigid roadbed according to claim 1, characterized in that: The foundation and anchoring structure of the contact network support are pre-buried on both sides of the top of the early-strength slightly expansive concrete.

8. A construction method for converting an existing railway bridge into a rigid roadbed, characterized in that: The method constructs the structure of claim 1, comprising: A pile foundation (1) is constructed below an existing bridge main beam (5), wherein the pile foundation (1) is arranged in a plurality of rows longitudinally; Backfilling the ground around the pile foundation (1) with lightweight concrete; A cap (2) is constructed on the top of the pile foundation (1) and above the backfilled lightweight concrete (6), a gap is left between the top surface of the cap (2) and the bottom surface of the existing bridge main beam (5), and a pre-buried steel plate (7) is arranged on the top surface of the cap (2); Constructing retaining walls (3) on the top of the cap (2) on both sides of the cap (2); Deploy beam lifting equipment below the existing bridge main beam (5), lift the beam and release the support of the existing bridge main beam (5), insert a filling steel plate (8) between the bottom of the existing bridge main beam (5) and the embedded steel plate (7), and convert the existing bridge main beam (5) to be supported by the pedestal (2) and the pile foundation (1); Early-strength slightly expansive concrete is poured in an area surrounded by the cap (2), the cap top retaining wall (3) and the existing bridge main beam (5).

9. The construction method for converting an existing railway bridge into a rigid roadbed according to claim 8, characterized in that: A pile foundation (1) is constructed below an existing bridge main beam (5), comprising: The pile foundation is constructed by artificially digging holes below the ground (1). When the bored pile wall reaches the designed strength, a steel casing is added above the ground and the bored pile is poured.

10. The construction method for converting an existing railway bridge into a rigid roadbed according to claim 9, characterized in that: The early-strength slightly expansive concrete is poured in two batches. After the existing bridge main beam (5) is converted to be supported by the pedestal (2) and the pile foundation (1), the phase II early-strength slightly expansive concrete (9) is poured in the area surrounded by the pedestal (2), the pedestal top retaining wall (3) and the existing bridge main beam (5), and then the phase III early-strength slightly expansive concrete (10) is poured on top of the phase II early-strength slightly expansive concrete (9).

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