Construction method for beam bridge substructure replacement

Abstract

The invention relates to the technical field of bridge construction, and provides a construction method for replacing a lower structure of a beam bridge, which comprises the following steps of: setting longitudinal bridge direction constraint, consolidating and horizontally fixing a damaged pier column, welding and fixing a support at the top of an old cover beam and a support pre-embedded steel plate at the bottom of a beam body, and constructing a gate-type pier assembly. A first jacking assembly, a second jacking assembly and a plane leveling assembly are arranged in an interlayer space, then the second jacking assembly is controlled to jack up a beam body, a damaged pier column is cut off, an old cover beam is leveled and reset, a new cover beam is combined with the old cover beam, a support on the top of the old cover beam is replaced, and then the old cover beam and the new cover beam are combined. And then the second jacking assembly is controlled to descend so that the beam body can be located on the new support to complete system conversion. The construction process is simple, the construction cost is reduced, meanwhile, the construction speed is high, the construction period can be shortened, the effect of rescue and relief work is achieved, the construction risk is reduced, meanwhile, compared with a damaged reinforcing mode, the quality is more reliable, and the risk of later geological disasters is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of bridge construction, and in particular to a construction method for replacing a beam bridge substructure. Background Art

[0002] With the development of my country's highway industry, a large number of bridges have been built in mountainous areas. Due to the limitations of terrain conditions, they will inevitably pass through high slopes and other unfavorable geological areas. High slope geology is prone to landslides under the influence of its own soil conditions, external rain erosion and human activities, causing certain damage to the lower structure of the bridge and even causing the bridge to collapse, especially the pier position is prone to damage.

[0003] There are two main methods for reinforcing traditional bridge substructures when they are damaged. One is to dismantle and rebuild from top to bottom. This construction method has a long construction period, affects people's normal traffic life, and has high construction costs and large economic losses. The other construction method is to strengthen the bridge by increasing the cross-section, pouring concrete into steel casings, and gluing fiber composite materials or steel plates after local correction. This method can meet the strength and stiffness requirements of the bridge during normal use to a certain extent. However, when the bridge is hit by geological disasters again in the future, the risk is high and dismantling and reconstruction is unavoidable because the bridge piers themselves are already damaged.

[0004] In view of this, it is necessary to propose a construction method for replacing the substructure of a beam bridge to solve or at least alleviate the above-mentioned defects. Summary of the invention

[0005] The main purpose of the present invention is to provide a construction method for replacing the substructure of a beam bridge, so as to solve the problems in the prior art that when the substructure of a bridge is damaged, the reconstruction method has a long period and high cost, and the local correction and reinforcement method has a high risk.

[0006] To achieve the above object, the present invention provides a construction method for replacing the substructure of a beam bridge, comprising the following steps: S1, a longitudinal bridge constraint is set between the abutment and the beam body near the damaged pier to prevent the beam body from longitudinal bridge displacement during the construction process; wherein an old cap beam is provided on the top of the damaged pier, a beam body is provided above the old cap beam, a support embedded steel plate is provided at the bottom of the beam body, a support is provided on the top of the old cap beam, and the support and the support embedded steel plate are slidably connected; S2, consolidating the damaged pier column and fixing the damaged pier column horizontally; S3, welding and fixing the support at the top of the old cap beam and the embedded steel plate of the support at the bottom of the beam body to prevent sliding between the old cap beam and the beam body; S4, constructing a portal bridge pier assembly; wherein the portal bridge pier assembly comprises a new pier column and a new cap beam arranged in sequence from top to bottom, the new cap beam is located directly below the old cap beam and a space between the new cap beam and the old cap beam is provided, the new pier column is arranged on the outside of the damaged pier column, the damaged pier column passes through the new cap beam and a post-cast space is provided between the new cap beam and the damaged pier column; S5, setting a first lifting assembly for lifting the old cap beam in the interlayer space, setting a second lifting assembly for lifting the beam body on the top surface of the new cap beam, and setting a plane leveling assembly on the top of the new cap beam; S6, cutting off the damaged pier column, and then controlling the second jacking assembly to jack up the beam body; S7, removing the welding connection between the support at the top of the old cap beam and the support embedded steel plate at the bottom of the beam body, and then leveling and resetting the old cap beam by using the first jacking assembly and the plane leveling assembly; S8, after the old cap beam is leveled and reset, the new cap beam is combined with the old cap beam; S9, replace the support at the top of the old cap beam, and then control the second jacking assembly to descend to seat the beam body on the new support to complete the system conversion.

[0007] Preferably, the step S1 specifically includes the following steps: S11, a longitudinal bridge constraint is set on the side of the abutment and the beam body near the damaged pier, wherein the longitudinal bridge constraint includes a connecting steel plate, a plurality of first anchor bars arranged at intervals along the longitudinal bridge direction, and a plurality of second anchor bars arranged at intervals along the longitudinal bridge direction, wherein one end of the first anchor bar is anchored inside the abutment, and the other end extends outward to the outside of the connecting steel plate; one end of the second anchor bar is anchored inside the beam body, and the other end extends outward to the outside of the connecting steel plate; S12, filling the expansion joint between the beam body and the abutment with wooden wedges and wooden strips.

[0008] Preferably, the step S2 specifically includes the following steps: S21, pouring concrete base on the existing ground at the damaged pier; S22, a steel sleeve formed by interlocking two semicircular steel plates is centrally placed on the outer periphery of the damaged pier column, the steel sleeve is placed on the concrete base, and C50 slightly expansive self-compacting concrete is poured into the steel sleeve to change the outer concrete of the damaged pier column from hinged to consolidated; S23, after drilling a hole in the horizontal direction to a designed depth using a drilling device, install a grouting anchor rod and perform grouting, and after the hydraulic slurry in the grouting anchor rod reaches a designed strength, weld one end of the grouting anchor rod close to the steel sleeve through an I-beam and the outer wall of the steel sleeve to horizontally fix the damaged pier column.

[0009] Preferably, the step S5 specifically includes the following steps: S51, plugging the post-casting space with steel wedges, and then arranging a first jacking assembly for jacking up the old cap beam in the interlayer space; wherein the first jacking assembly includes a first base frame and a first jack installed on the top of the first base frame; S52, arranging a second lifting assembly for lifting the beam body on the top surface of the new cap beam, and arranging scissor braces between the second lifting assemblies; S53, a plane leveling assembly is arranged on the top of the new cap beam; wherein, the plane leveling assembly includes a second base frame and four lateral pushing units arranged in a matrix, the bottom of the second base frame is slidably arranged on the top surface of the new cap beam, the top of the second base frame is fixedly connected to the old cap beam, each lateral pushing unit includes a reaction frame and a second jack, the reaction frame is fixed to the top of the new cap beam, the second jack includes a first end and a second end, the first end is in contact with the reaction frame, and the second end is in contact with the first base frame; wherein, the second base frame is pushed by the second jack to slide on the top surface of the new cap beam.

[0010] Preferably, the step S6 specifically includes the following steps: S61, release the steel sleeve from the damaged pier; S62, starting from the bottom surface of the new cap beam, cut off the old damaged pier in sections downward until it reaches the ground line; S63, then control the second lifting assembly to lift the beam body.

[0011] Preferably, the step S8 specifically includes the following steps: S81, arc welding is used to weld the upper end of the vertical steel rod to the first embedded steel plate embedded in the bottom of the old cap beam, and the lower end of the vertical steel rod is welded to the second embedded steel plate embedded in the top of the new cap beam to form a rigid support, and then the plane leveling assembly is removed; S82, using concrete of the same grade as that of the new cap beam, pour concrete into the post-cast space to combine the new cap beam with the old cap beam.

[0012] Preferably, the step S9 specifically includes the following steps: After the new cap beam is combined with the old cap beam, the support bolts on the top of the damaged pier column are removed to abolish the support on the top of the damaged pier column; Check whether the bearing pad stone is damaged. If the bearing pad stone is not damaged, use a grinding wheel grinder to remove the debris on the bearing pad stone and smooth it, and then install the same model of pot-type bearing.

[0013] Preferably, if the bearing pedestal is damaged and cannot be used normally, the pedestal concrete is manually chiseled out with an electric hammer, the embedded steel bars of the bearing pedestal are retained, the steel mesh is reinstalled, the bearing pedestal is recast, and then the same type of pot-type bearing is installed.

[0014] Preferably, the first chassis adopts 20 I-beams, and the second chassis adopts 36 I-beams.

[0015] Compared with the prior art, the present invention has the following beneficial effects: (1) Compared with the traditional demolition and reconstruction construction method, this method has a simple construction process, which can save labor costs, equipment costs and material costs for demolishing and rebuilding the superstructure, thus reducing construction costs. At the same time, the construction speed is fast, which can save construction time, achieve the effect of emergency rescue and disaster relief, and reduce construction risks.

[0016] (2) Compared with the traditional construction method of reinforcing the lower structure, this construction method does not require a large number of supports to stabilize the upper structure first. Instead, the newly built portal pier assembly is used as a support to stabilize the upper structure. At the same time, the newly built portal pier assembly is used as a platform for correcting the deviation of the upper structure, which saves a lot of materials and simplifies the construction process. At the same time, compared with the damaged reinforced piers, the quality of this application is more reliable and the risk of later geological disasters is reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] 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, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0018] Figure 1 It is a schematic diagram of a construction method in one embodiment of the present invention; Figure 2 This is a flow chart showing the specific steps included in step S2 in one embodiment of the present invention; Figure 3 This is a flowchart of the specific steps included in step S5 in one embodiment of the present invention; Figure 4 This is a schematic diagram of the structure after step S1 is completed in one embodiment of the present invention; Figure 5 It is a schematic structural diagram of a damaged pier column after consolidation in one embodiment of the present invention; Figure 6 It is a schematic structural diagram of a damaged pier column after horizontal fixation in one embodiment of the present invention; Figure 7This is a schematic diagram of the structure after step S3 is completed in one embodiment of the present invention; Figure 8 It is a schematic diagram of the structure after the construction of step S4 in one embodiment of the present invention; Fig. 9 for Figure 8 Schematic diagram of the plane; Fig.10 It is a schematic diagram of the structure after construction step S5 in one embodiment of the present invention; Fig.11 It is a schematic diagram of the structure after construction step S7 in one embodiment of the present invention; Fig.12 It is a schematic diagram of the structure after construction step S8 in one embodiment of the present invention.

[0019] The purpose, features and advantages of the present invention will be further described with reference to the accompanying drawings in conjunction with the embodiments.

[0020] Description of Figure Numbers: 10. Abutment; 20. Beam; 210. Expansion joint; 220. Longitudinal restraint; 221. Connecting steel plate; 222. First anchor bar; 223. Second anchor bar; 224. Wooden wedge block; 30. Damaged pier column; 310. Concrete base; 320. Steel sleeve; 330. Grouting anchor rod; 40. Old cap beam; 410. Support; 50. Portal pier assembly; 510. New pier column; 520. New cap beam; 521. Post-cast space; 530. Interlayer space; 540. First lifting assembly; 541. First base frame; 542. First jack; 550. Second lifting assembly; 551. Steel pipe column; 552. Third jack; 553. Scissors brace; 560. Plane leveling assembly; 561. Second base frame; 562. Reaction frame; 563. Second jack. DETAILED DESCRIPTION

[0021] 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.

[0022] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] In the present invention, the descriptions involving "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in the field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0024] Please see attached Figures 1 to 12 In one embodiment of the present invention, a construction method for replacing a beam bridge substructure includes the following steps: S1, a longitudinal bridge constraint 220 is set between the abutment 10 and the beam body 20 near the damaged pier 30 to prevent the beam body 20 from longitudinal bridge displacement during the construction process; wherein, an old cap beam 40 is provided on the top of the damaged pier 30, a beam body 20 is provided above the old cap beam 40, a support embedded steel plate (not shown) is provided at the bottom of the beam body 20, a support 410 is provided on the top of the old cap beam 40, and the support 410 and the support embedded steel plate are slidably connected; S2, consolidating the damaged pier column 30 and fixing the damaged pier column 30 horizontally; S3, welding and fixing the support 410 at the top of the old cap beam 40 and the support embedded steel plate at the bottom of the beam body 20 to prevent sliding between the old cap beam 40 and the beam body 20; Specifically, Figures 4 to 7 , steps S1 to S3 are to reinforce the existing bridge structure. Step S1 prevents the beam body 20 from being displaced in the longitudinal direction of the bridge during the construction process. Step S2 fixes the damaged pier 30 horizontally to prevent the damaged pier 30 from further moving in the horizontal direction. Step S3 welds and fixes the support 410 at the top of the old cap beam 40 to the embedded steel plate of the support at the bottom of the beam body 20 to prevent sliding between the old cap beam 40 and the beam body 20. As a preferred example, a hanging basket can be used for construction. After the hanging basket is inspected and qualified, it should be repeatedly lifted and lowered twice after installation. Construction can be carried out only after no abnormality is found. During construction, a construction worker is arranged to work in the hanging basket with an electric welding machine to weld and fix the support 410 at the top of the old cap beam 40 to the embedded steel plate of the support at the bottom of the beam body 20.

[0025] S4, constructing a portal bridge pier assembly 50; wherein the portal bridge pier assembly 50 comprises a new pier column 510 and a new cap beam 520 arranged in sequence from top to bottom, the new cap beam 520 is located directly below the old cap beam 40 and a space 530 is provided between the new cap beam 520 and the old cap beam 40, the new pier column 510 is arranged on the outside of the damaged pier column 30, the damaged pier column 30 passes through the new cap beam 520 and a post-cast space 521 is provided between the new cap beam 520 and the damaged pier column 30, which can be referred to in the attached Figures 7 and 8 .

[0026] S5, a first lifting assembly 540 for lifting the old cap beam 40 is arranged in the interlayer space 530, a second lifting assembly 550 for lifting the beam body 20 is arranged on the top surface of the new cap beam 520, and a plane leveling assembly 560 is arranged on the top of the new cap beam 520. Figure 10 to Figure 11 At this time, the first lifting assembly 540, the second lifting assembly 550 and the plane leveling assembly 560 are all in the initial state.

[0027] S6, cut off the damaged pier 30, and then control the second jacking assembly 550 to jack up the beam body 20; after the damaged pier 30 is cut off, the second jacking assembly 550 can be controlled to jack up the beam body 20, so as to remove the welding connection between the support 410 at the top of the old cap beam 40 and the support embedded steel plate at the bottom of the beam body 20; Furthermore, the step S6 specifically includes the following steps: S61, removing the steel sleeve 320 of the damaged pier 30; S62, cutting off the old damaged pier 30 in sections downward from the bottom surface position of the new cap beam 520 until it is cut off to the ground line position; S63, then controlling the second jacking assembly 550 to jack up the beam body 20.

[0028] S7, remove the welding connection between the support 410 at the top of the old cap beam 40 and the embedded steel plate of the support at the bottom of the beam body 20, and then level and reset the old cap beam 40 through the first jacking assembly 540 and the plane leveling assembly 560; after the welding connection is released, since the beam body 20 is now lifted up by the second jacking assembly 550, the old cap beam 40 and the beam body 20 are in a separated state, so the old cap beam 40 can be leveled and reset through the first jacking assembly 540 and the plane leveling assembly 560, wherein the first jacking assembly 540 can adjust the vertical height of the old cap beam 40, and the plane leveling assembly 560 can adjust the posture of the old cap beam 40 in the horizontal plane, and the two can be combined to adjust the three-dimensional spatial posture of the old cap beam 40, thereby realizing the leveling and resetting of the old cap beam 40.

[0029] S8, after the old cap beam 40 is leveled and reset, the new cap beam 520 is combined with the old cap beam 40; S9, replace the support 410 at the top of the old cap beam 40, and then control the second jacking assembly 550 to descend to seat the beam body 20 on the new support to complete the system conversion.

[0030] In the present application, a longitudinal bridge constraint 220 is set between the abutment 10 and the beam body 20 to prevent longitudinal displacement caused by external force or deadweight during construction, thereby ensuring the overall stability of the bridge; the damaged pier 30 is reinforced to improve its bearing capacity, and horizontal fixing measures are taken to prevent lateral movement during construction, thereby providing a stable foundation for subsequent construction; the support 410 at the top of the old cap beam 40 is welded to the embedded steel plate of the support at the bottom of the beam body 20 to form a temporary fixation to prevent the old cap beam 40 from being swayed from the beam body 20 The relative sliding between the two sides ensures the stable support of the beam body 20 before jacking; a new pier 510 is set outside the damaged pier 30, and a new cap beam 520 is installed above it to form a portal pier assembly 50. A mezzanine space 530 is reserved between the new cap beam 520 and the old cap beam 40 to provide space for the post-cast concrete between the new pier 510 and the old pier. A first jacking assembly 540 is installed in the mezzanine space 530 to jack up the old cap beam 40; a second jacking assembly 550 is installed on the top surface of the new cap beam 520 to jack up the beam body 20. At the same time, a plane leveling assembly 560 is set on the top of the new cap beam 520 to level and reset the old cap beam 40. The old cap beam 40 is accurately leveled and reset using the first jacking assembly 540 and the plane leveling assembly 560. After the old cap beam 40 is leveled and reset, the new cap beam 520 is tightly combined with the old cap beam 40 to form a new support structure. Replace the support 410 on the top of the old cap beam 40 to ensure that the new support is tightly fitted with the embedded steel plate at the bottom of the beam body 20. Then, control the second jacking assembly 550 to slowly descend so that the beam body 20 is stably seated on the new support, completing the system conversion from the old pier to the new pier 510.

[0031] (1) Compared with the traditional demolition and reconstruction construction method, this method has a simple construction process, which can save labor costs, equipment costs and material costs for demolishing and rebuilding the superstructure, thus reducing construction costs. At the same time, the construction speed is fast, which can save construction time, achieve the effect of emergency rescue and disaster relief, and reduce construction risks.

[0032] (2) Compared with the traditional construction method of reinforcing the lower structure, this construction method does not require a large number of supports to stabilize the upper structure first. Instead, the newly built portal pier assembly 50 is used as a support to stabilize the upper structure. At the same time, the newly built portal pier assembly 50 is used as a platform for correcting the deviation of the upper structure, which saves a lot of materials and simplifies the construction process. At the same time, compared with the damaged and reinforced piers, the quality of the newly built piers is more reliable, reducing the risk of later geological disasters.

[0033] (3) The installation of the new pier 510 and the new cap beam 520 not only replaced the damaged part, but also improved the overall bearing capacity and durability of the bridge through optimized design. The provision of the post-cast space 521 allows concrete to be poured between the new cap beam 520 and the damaged pier 30, further enhancing the integrity and stability of the structure.

[0034] As a preferred implementation, step S1 specifically includes the following steps: S11, a longitudinal bridge constraint 220 is set on the side of the abutment 10 and the beam body 20 near the damaged pier 30, and the longitudinal bridge constraint 220 includes a connecting steel plate 221, a plurality of first anchor bars 222 arranged at intervals along the longitudinal bridge direction, and a plurality of second anchor bars 223 arranged at intervals along the longitudinal bridge direction, one end of the first anchor bar 222 is anchored inside the abutment 10, and the other end extends outward to the outside of the connecting steel plate 221; one end of the second anchor bar 223 is anchored inside the beam body 20, and the other end extends outward to the outside of the connecting steel plate 221; S12, filling the expansion joint 210 between the beam body 20 and the abutment 10 with wooden wedges and wooden strips 224.

[0035] Specifically, during the actual construction process, the width of the expansion joint 210 between the abutment 10 and the beam body 20 is measured on site with a steel ruler, and is marked and recorded. According to the measured width, the wood wedges and wood strips 224 are processed according to the determined size at a nearby wood processing plant, such as Figure 4 As shown, longitudinal bridge constraints 220 are set on the sides of the abutment 10 and the beam 20 near the damaged pier 30 to prevent the beam 20 from undergoing longitudinal bridge horizontal displacement toward the opposite abutment 10, and wooden wedges and wooden strips 224 are filled in the expansion joint 210 between the beam 20 and the abutment 10 to prevent the beam 20 from undergoing longitudinal bridge horizontal displacement toward the abutment 10 on the current side.

[0036] As a preferred implementation, step S2 specifically includes the following steps: S21, pouring a concrete base 310 on the existing ground at the damaged pier 30; as a specific example, a reinforced concrete base 310 with a thickness of at least 150 cm can be poured on the existing ground line at the damaged pier 30, with the central axis of the damaged pier 30, within a range of 400 cm along the bridge direction (200 cm on each side) and 800 cm across the bridge direction, for the placement of the steel sleeve 320.

[0037] S22, a steel sleeve 320 formed by buckling two semicircular steel plates is centrally sleeved on the outer periphery of the damaged pier 30, the steel sleeve 320 is placed on the concrete base 310, and C50 slightly expansive self-compacting concrete is poured into the steel sleeve 320 to change the outer concrete of the damaged pier 30 from being hinged to being consolidated; As a specific example, two semicircular steel plates (thickness 12 mm) are interlocked to form a steel sleeve 320 with a diameter of D280 cm (outer diameter) which is centrally sleeved on the outside of the damaged pier 30. The steel sleeve 320 is placed on the concrete base 310, and C50 slightly expanding self-compacting concrete is poured into the steel sleeve 320 to change the outer concrete of the damaged pier 30 from being hinged to being consolidated.

[0038] S23, after drilling a hole in the horizontal direction to the designed depth using a drilling device, install the grouting anchor rod 330 and perform grouting, and after the hydraulic slurry in the grouting anchor rod 330 reaches the designed strength, weld one end of the grouting anchor rod 330 close to the steel sleeve 320 through an I-beam and the outer wall of the steel sleeve 320 to horizontally fix the damaged pier column 30. Preferably, the I-beam adopts a 20 I-beam.

[0039] As a preferred implementation, step S5 specifically includes the following steps: S51, a steel wedge is used to plug the post-casting space 521 to prevent the damaged pier 30 from moving, and then a first lifting assembly 540 for lifting the old cap beam 40 is arranged in the interlayer space 530; wherein the first lifting assembly 540 includes a first base frame 541 and a first jack 542 installed on the top of the first base frame 541; S52, a second lifting assembly 550 for lifting the beam body 20 is arranged on the top surface of the new cap beam 520, and a scissor support 553 is arranged between the second lifting assemblies 550; Specifically, Fig.10 As shown, a second lifting component 550 for lifting the beam body 20 is provided on the top surface of the new cap beam 520. For example, a steel pipe column 551 with a diameter of Φ300mm and a wall thickness of 10mm is used as a jack base support at the bottom of the beam body 20. Each steel pipe column 551 is 2 meters long and is pre-processed and cut in the factory before being transported to the construction site. The steel pipe column 551 is lifted to the top edge of the new cap beam 520 by a truck crane. A temporary support is erected on the top surface of the new cap beam 520 by using a ø50 steel pipe rack, and a hand winch is hung. The steel pipe column 551 is moved to a predetermined position on the top surface of the new cap beam 520 by using the hand winch and is welded and fixed to the embedded steel plate on the top surface of the new cap beam 520. Further, a scissors brace 553 can be provided between the steel pipe columns 551 to enhance the stability of the steel pipe columns 551.

[0040] S53, a plane leveling component 560 is set on the top of the new cap beam 520; wherein, the plane leveling component 560 includes a second base frame 561 and four lateral pushing units (not shown in the figure) arranged in a matrix, the bottom of the second base frame 561 is slidably set on the top surface of the new cap beam 520, the top of the second base frame 561 is fixedly connected to the old cap beam 40, each lateral pushing unit includes a reaction frame 562 and a second jack 563, the reaction frame 562 is fixed to the top of the new cap beam 520, the second jack 563 includes a first end (not shown in the figure) and a second end (not shown in the figure), the first end is in contact with the reaction frame 562, and the second end is in contact with the first base frame 541; wherein, the second base frame 561 is pushed to slide on the top surface of the new cap beam 520 by the second jack 563.

[0041] As a preferred implementation, step S8 specifically includes the following steps: S81, arc welding is used to weld the upper end of the vertical steel rod at the bottom of the old cap beam 40 to the first embedded steel plate embedded at the bottom of the old cap beam 40, and the lower end of the vertical steel rod is welded to the second embedded steel plate embedded at the top of the new cap beam 520 to form a rigid support, and then the plane leveling assembly 560 is removed; S82, using concrete of the same grade as that of the new cap beam 520, pouring concrete into the post-cast space 521 to combine the new cap beam 520 with the old cap beam 40.

[0042] Specifically, after the old cap beam 40 is leveled and reset, the upper end of the vertical steel rod at the bottom of the old cap beam 40 is welded to the first embedded steel plate embedded in the bottom of the old cap beam 40 by arc welding, and the lower end of the vertical steel rod is welded to the second embedded steel plate embedded in the top of the new cap beam 520 to form a rigid support, and then the plane leveling assembly 560 is removed; concrete with the same grade as the new cap beam 520 is used to pour concrete into the post-cast space 521.

[0043] Furthermore, the step S9 specifically includes the following steps: After the new cap beam 520 is combined with the old cap beam 40, the bolts of the support 410 on the top of the damaged pier column 30 are released, and the support 410 on the top of the damaged pier column 30 is abolished; Check whether the support 410 pad stone is damaged. If the support 410 pad stone is not damaged, use a grinding wheel grinder to remove the debris on the support 410 pad stone and then install the same model of pot-type support 410.

[0044] Furthermore, if the support 410 pad stone is damaged and cannot be used normally, the pad stone concrete is manually chiseled out using an electric hammer, the embedded steel bars of the support 410 pad stone are retained, the steel mesh is reinstalled, the support 410 pad stone is recast, and then the same model of pot-type support 410 is installed.

[0045] As a preferred example, the first base frame 541 uses 20 I-beams, and the second base frame 561 uses 36 I-beams.

[0046] The above are only preferred embodiments of the present invention, and the protection scope of the present invention is not limited thereto. Any equivalent structure or equivalent process transformation made by using the contents of the specification and drawings of the present invention, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A construction method for replacing the substructure of a beam bridge, characterized in that: The following steps are involved: S1, a longitudinal bridge constraint is set between the abutment and the beam body near the damaged pier to prevent the beam body from longitudinal bridge displacement during the construction process; wherein an old cap beam is provided on the top of the damaged pier, a beam body is provided above the old cap beam, a support embedded steel plate is provided at the bottom of the beam body, a support is provided on the top of the old cap beam, and the support and the support embedded steel plate are slidably connected; S2, consolidating the damaged pier column and fixing the damaged pier column horizontally; S3, welding and fixing the support at the top of the old cap beam and the embedded steel plate of the support at the bottom of the beam body to prevent sliding between the old cap beam and the beam body; S4, constructing a portal bridge pier assembly; wherein the portal bridge pier assembly comprises a new pier column and a new cap beam arranged in sequence from top to bottom, the new cap beam is located directly below the old cap beam and a space between the new cap beam and the old cap beam is provided, the new pier column is arranged on the outside of the damaged pier column, the damaged pier column passes through the new cap beam and a post-cast space is provided between the new cap beam and the damaged pier column; S5, setting a first lifting assembly for lifting the old cap beam in the interlayer space, setting a second lifting assembly for lifting the beam body on the top surface of the new cap beam, and setting a plane leveling assembly on the top of the new cap beam; S6, cutting off the damaged pier column, and then controlling the second jacking assembly to jack up the beam body; S7, removing the welding connection between the support at the top of the old cap beam and the support embedded steel plate at the bottom of the beam body, and then leveling and resetting the old cap beam by using the first jacking assembly and the plane leveling assembly; S8, after the old cap beam is leveled and reset, the new cap beam is combined with the old cap beam; S9, replace the support at the top of the old cap beam, and then control the second jacking assembly to descend to seat the beam body on the new support to complete the system conversion.

2. The construction method for replacing the substructure of a beam bridge according to claim 1, characterized in that: The step S1 specifically includes the following steps: S11, a longitudinal bridge constraint is set on the side of the abutment and the beam body near the damaged pier, wherein the longitudinal bridge constraint includes a connecting steel plate, a plurality of first anchor bars arranged at intervals along the longitudinal bridge direction, and a plurality of second anchor bars arranged at intervals along the longitudinal bridge direction, wherein one end of the first anchor bar is anchored inside the abutment, and the other end extends outward to the outside of the connecting steel plate; one end of the second anchor bar is anchored inside the beam body, and the other end extends outward to the outside of the connecting steel plate; S12, filling the expansion joint between the beam body and the abutment with wooden wedges and wooden strips.

3. The construction method for replacing the substructure of a beam bridge according to claim 1, characterized in that: The step S2 specifically includes the following steps: S21, pouring concrete base on the existing ground at the damaged pier; S22, a steel sleeve formed by interlocking two semicircular steel plates is centrally placed on the outer periphery of the damaged pier column, the steel sleeve is placed on the concrete base, and C50 slightly expansive self-compacting concrete is poured into the steel sleeve to change the outer concrete of the damaged pier column from hinged to consolidated; S23, after drilling a hole in the horizontal direction to a designed depth using a drilling device, install a grouting anchor rod and perform grouting, and after the hydraulic slurry in the grouting anchor rod reaches a designed strength, weld one end of the grouting anchor rod close to the steel sleeve through an I-beam and the outer wall of the steel sleeve to horizontally fix the damaged pier column.

4. The construction method for replacing the lower structure of a beam bridge according to claim 1, characterized in that: The step S5 specifically comprises the following steps: S51, plugging the post-casting space with steel wedges, and then arranging a first jacking assembly for jacking up the old cap beam in the interlayer space; wherein the first jacking assembly includes a first base frame and a first jack installed on the top of the first base frame; S52, arranging a second lifting assembly for lifting the beam body on the top surface of the new cap beam, and arranging scissor braces between the second lifting assemblies; S53, a plane leveling assembly is arranged on the top of the new cap beam; wherein, the plane leveling assembly includes a second base frame and four lateral pushing units arranged in a matrix, the bottom of the second base frame is slidably arranged on the top surface of the new cap beam, the top of the second base frame is fixedly connected to the old cap beam, each lateral pushing unit includes a reaction frame and a second jack, the reaction frame is fixed to the top of the new cap beam, the second jack includes a first end and a second end, the first end is in contact with the reaction frame, and the second end is in contact with the first base frame; wherein, the second base frame is pushed by the second jack to slide on the top surface of the new cap beam.

5. The construction method for replacing the lower structure of a beam bridge according to claim 4, characterized in that: The step S6 specifically comprises the following steps: S61, release the steel sleeve from the damaged pier; S62, starting from the bottom surface of the new cap beam, cut off the old damaged pier in sections downward until it reaches the ground line; S63, then control the second lifting assembly to lift the beam body.

6. The construction method for replacing the substructure of a beam bridge according to claim 5, characterized in that: The step S8 specifically includes the following steps: S81, arc welding is used to weld the upper end of the vertical steel rod to the first embedded steel plate embedded in the bottom of the old cap beam, and the lower end of the vertical steel rod is welded to the second embedded steel plate embedded in the top of the new cap beam to form a rigid support, and then the plane leveling assembly is removed; S82, using concrete of the same grade as that of the new cap beam, pour concrete into the post-cast space to combine the new cap beam with the old cap beam.

7. The construction method for replacing the lower structure of a beam bridge according to claim 1, characterized in that: The step S9 specifically includes the following steps: After the new cap beam is combined with the old cap beam, the support bolts on the top of the damaged pier column are removed to abolish the support on the top of the damaged pier column; Check whether the bearing pad stone is damaged. If the bearing pad stone is not damaged, use a grinding wheel grinder to remove the debris on the bearing pad stone and smooth it, and then install the same model of pot-type bearing.

8. The construction method for replacing the lower structure of a beam bridge according to claim 7, characterized in that: If the bearing pad stone is damaged and cannot be used normally, the pad stone concrete is manually chiseled out using an electric hammer, the embedded steel bars of the bearing pad stone are retained, the steel mesh is reinstalled, the bearing pad stone is re-poured, and then the same type of pot-type bearing is installed.

9. The construction method for replacing the lower structure of a beam bridge according to claim 4, characterized in that: The first base frame adopts 20 I-beams, and the second base frame adopts 36 I-beams.

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