A construction method for replacing the lower structure of a beam bridge

Abstract

The present invention relates to the technical field of bridge construction, and provides a construction method for replacing the lower structure of a beam bridge, by setting longitudinal bridge constraints, consolidating and horizontally fixing the damaged piers, welding and fixing the support at the top of the old cap beam to the support embedded steel plate at the bottom of the beam body, constructing a portal pier assembly, setting a first jacking assembly, a second jacking assembly, and a plane leveling assembly in the interlayer space, and then controlling the second jacking assembly to jack up the beam body, cut off the damaged piers, and then level and reset the old cap beam, combine the new cap beam with the old cap beam, 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. The application has a simple construction process, reduces construction costs, and has a fast construction speed, which can save construction time, achieve the effect of emergency rescue, and reduce construction risks. At the same time, compared with the damaged reinforcement method, the quality is more reliable and the risk of later geological disasters is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of bridge construction, and particularly to a construction method for replacing the lower structure of a beam bridge. Background Art

[0002] With the development of China's highway industry, a large number of bridges have been built in mountainous areas. Due to the limitation of topographic conditions, it is inevitable to cross adverse geological areas such as high slopes. Under the influence of its own soil conditions, external rainwater scouring and human activities, the high-slope geology is prone to landslides, causing certain damage to the lower structure of the bridge and even causing the bridge to collapse. In particular, the pier position is easily damaged.

[0003] There are mainly two methods for strengthening the traditional lower structure of a bridge when it is damaged. One is to demolish and rebuild from top to bottom. This construction method has a long construction period, affects people's normal traffic life, and has a high construction cost and large economic losses. The other construction method is to reinforce by increasing the cross-section, pouring concrete into a steel casing, pasting fiber composite materials or steel plates after local correction. This method can meet the strength and stiffness during the normal use of the bridge to a certain extent. However, when a geological disaster occurs again in the future bridge, due to the existing damage to the pier itself, the risk is high and it is impossible to avoid demolition and reconstruction.

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

[0005] The main purpose of the present invention is to provide a construction method for replacing the lower structure of a beam bridge to solve the problems of long cycle and high cost in the reconstruction method and high risk in the local correction and reinforcement method when the lower structure of the bridge is damaged in the prior art.

[0006] To achieve the above object, the present invention provides a construction method for replacing the lower structure of a beam bridge, including the following steps:

[0007] S1, a longitudinal bridge constraint is set between the abutment and the beam near the damaged pier to prevent the longitudinal displacement of the beam during the construction process; wherein, an old capping beam is provided at the top of the damaged pier, a beam is provided above the old capping beam, a bearing embedded steel plate is provided at the bottom of the beam, a bearing is provided at the top of the old capping beam, and a slidable connection is provided between the bearing and the bearing embedded steel plate;

[0008] S2, consolidate the damaged pier and horizontally fix the damaged pier;

[0009] S3, weld and fix the bearing at the top of the old capping beam and the bearing embedded steel plate at the bottom of the beam to prevent sliding between the old capping beam and the beam;

[0010] 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 bottom to top, the new cap beam is located directly below the old cap beam and a space is provided between the new cap beam and the old cap beam, the new pier column is arranged outside 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;

[0011] 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;

[0012] S6, cutting off the damaged pier column, and then controlling the second jacking assembly to jack up the beam body;

[0013] 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;

[0014] S8, after the old cap beam is leveled and reset, the new cap beam is combined with the old cap beam;

[0015] 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.

[0016] Preferably, the step S1 specifically includes the following steps:

[0017] 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;

[0018] S12, filling the expansion joint between the beam body and the abutment with wooden wedges and wooden strips.

[0019] Preferably, the step S2 specifically includes the following steps:

[0020] S21, pouring concrete base on the existing ground at the damaged pier;

[0021] 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;

[0022] In S23, after drilling horizontally to the designed depth by a drilling device, a grouting bolt is installed and grouted. After the hydraulic grout in the grouting bolt reaches the designed strength, one end of the grouting bolt close to the steel sleeve is welded to the outer wall of the steel sleeve through an I-beam to horizontally fix the damaged pier column.

[0023] Preferably, the step S5 specifically includes the following steps:

[0024] In S51, steel wedges are tightly wedged in the post-cast space, and then a first jacking assembly for jacking up the old capping beam is arranged in the partition space; wherein, the first jacking assembly includes a first bottom frame and a first jack installed on the top of the first bottom frame;

[0025] In S52, a second jacking assembly for jacking up the beam body is arranged on the top surface of the new capping beam, and a cross brace is arranged between the second jacking assemblies;

[0026] In S53, a plane leveling assembly is arranged on the top of the new capping beam; wherein, the plane leveling assembly includes a second bottom frame and four lateral jacking units arranged in a matrix. The bottom of the second bottom frame is slidably arranged on the top surface of the new capping beam, the top of the second bottom frame is fixedly connected to the old capping beam, each lateral jacking unit includes a reaction frame and a second jack. The reaction frame is fixed to the top of the new capping beam. The second jack includes a first end and a second end. The first end contacts the reaction frame, and the second end contacts the first bottom frame; wherein, the second bottom frame is pushed by the second jack to slide on the top surface of the new capping beam.

[0027] Preferably, the step S6 specifically includes the following steps:

[0028] In S61, the steel sleeve of the damaged pier column is removed;

[0029] In S62, the old damaged pier column is cut off in segments downward from the bottom surface position of the new capping beam until it is cut off to the ground line position;

[0030] In S63, then control the second jacking assembly to jack up the beam body.

[0031] Preferably, the step S8 specifically includes the following steps:

[0032] In S81, the upper end of the vertical steel bar is welded to the first embedded steel plate embedded at the bottom of the old capping beam by arc welding at the bottom of the old capping beam, and the lower end of the vertical steel bar is welded to the second embedded steel plate embedded at the top of the new capping beam to form a rigid support, and then the plane leveling assembly is removed;

[0033] In S82, concrete of the same grade as the new capping beam is used to pour concrete into the post-cast space to combine the new capping beam with the old capping beam.

[0034] Preferably, the step S9 specifically includes the following steps:

[0035] 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;

[0036] 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.

[0037] 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.

[0038] Preferably, the first chassis adopts 20 I-beams, and the second chassis adopts 36 I-beams.

[0039] Compared with the prior art, the present invention has the following beneficial effects:

[0040] (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.

[0041] (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

[0042] 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.

[0043] Figure 1 It is a schematic diagram of a construction method in one embodiment of the present invention;

[0044] Figure 2 This is a flow chart showing the specific steps included in step S2 in one embodiment of the present invention;

[0045] Figure 3 The flowchart showing the specific steps included in step S5 in an embodiment of the present invention;

[0046] Figure 4 The structural schematic diagram after completing step S1 in an embodiment of the present invention;

[0047] Figure 5 The structural schematic diagram after consolidating the damaged pier column in an embodiment of the present invention;

[0048] Figure 6 The structural schematic diagram after horizontally fixing the damaged pier column in an embodiment of the present invention;

[0049] Figure 7 The structural schematic diagram after completing step S3 in an embodiment of the present invention;

[0050] Figure 8 The structural schematic diagram after completing step S4 in an embodiment of the present invention;

[0051] Figure 9 is Figure 8 the plan view of;

[0052] Figure 10 The structural schematic diagram after step S5 of the construction steps in an embodiment of the present invention;

[0053] Figure 11 The structural schematic diagram after step S7 of the construction steps in an embodiment of the present invention;

[0054] Figure 12 The structural schematic diagram after step S8 of the construction steps in an embodiment of the present invention.

[0055] The realization of the object, functional features and advantages of the present invention will be further described with reference to the embodiments and the accompanying drawings.

[0056] Explanation of the reference numerals in the drawings:

[0057] 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

[0058] 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.

[0059] 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.

[0060] 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.

[0061] 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:

[0062] 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;

[0063] S2, consolidating the damaged pier column 30 and fixing the damaged pier column 30 horizontally;

[0064] 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;

[0065] 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.

[0066] 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 bottom to top, 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 to 8 .

[0067] 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. Figures 10 to 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.

[0068] 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;

[0069] Furthermore, step S6 specifically includes the following steps: S61, remove the steel sleeve 320 of the damaged pier column 30; S62, segmentally cut the old damaged pier column 30 downward starting from the bottom surface position of the new capping beam 520 until reaching the ground line position; S63, then control the second jacking assembly 550 to jack up the beam body 20.

[0070] S7, remove the welding connection between the bearing 410 at the top of the old capping beam 40 and the embedded steel plate at the bottom of the beam body 20, and then level and reset the old capping beam 40 through the first jacking assembly 540 and the plane leveling assembly 560; after the welding connection is removed, since the beam body 20 is jacked up by the second jacking assembly 550 at this time and the old capping beam 40 and the beam body 20 are in a separated state, the old capping beam 40 can be leveled and reset through the first jacking assembly 540 and the plane leveling assembly 560. Among them, the first jacking assembly 540 can adjust the vertical height of the old capping beam 40, and the plane leveling assembly 560 can adjust the attitude of the old capping beam 40 in the horizontal plane. Combining the two can adjust the three-dimensional space attitude of the old capping beam 40, so as to realize the leveling and reset of the old capping beam 40.

[0071] S8, after the old capping beam 40 is leveled and reset, combine the new capping beam 520 with the old capping beam 40;

[0072] S9, replace the bearing 410 at the top of the old capping beam 40, and then control the second jacking assembly 550 to lower to seat the beam body 20 on the new bearing to complete the system conversion.

[0073] In the solution of this application, a longitudinal bridge constraint 220 is provided between the abutment 10 and the beam body 20 to prevent longitudinal displacement caused by external forces or self-weight during construction and ensure the overall stability of the bridge; the damaged pier column 30 is strengthened to improve its bearing capacity, and horizontal fixing measures are adopted to prevent its lateral movement during construction, providing a stable foundation for subsequent construction; the bearing 410 on the top of the old capping beam 40 is welded to the embedded steel plate at the bottom of the beam body 20 to form a temporary fixation, preventing relative sliding between the old capping beam 40 and the beam body 20 and ensuring stable support of the beam body 20 before jacking; a new pier column 510 is arranged outside the damaged pier column 30, and a new capping beam 520 is installed above it to form a portal pier assembly 50. A separation space 530 is reserved between the new capping beam 520 and the old capping beam 40 to provide space for the post-cast concrete between the new pier column 510 and the old pier column. A first jacking assembly 540 is installed in the separation space 530 for jacking the old capping beam 40; a second jacking assembly 550 is installed on the top surface of the new capping beam 520 for jacking the beam body 20. At the same time, a plane leveling assembly 560 is arranged on the top of the new capping beam 520 for leveling and resetting the old capping beam 40. The first jacking assembly 540 and the plane leveling assembly 560 are used to precisely level and reset the old capping beam 40. After the old capping beam 40 is leveled and reset, the new capping beam 520 is closely combined with the old capping beam 40 to form a new support structure. The bearing 410 on the top of the old capping beam 40 is replaced to ensure that the new bearing is closely attached to the embedded steel plate at the bottom of the beam body 20. Then, the second jacking assembly 550 is controlled to slowly descend, so that the beam body 20 is smoothly seated on the new bearing, completing the system conversion from the old pier column to the new pier column 510.

[0074] (1) Adopting this construction method, compared with the traditional construction method of demolition and reconstruction, the construction process of this method is simple. It can not only save the labor cost, equipment cost and material cost of demolishing and constructing the upper structure, reduce the construction cost, but also has a fast construction speed, can save the construction period, achieve the effect of disaster relief and reduce the construction risk.

[0075] (2) Adopting this construction method, compared with the traditional construction method of strengthening the lower structure, it does not require a large number of supports to stabilize the upper structure first, but uses the newly built portal pier assembly 50 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, saving a large amount of materials, simplifying the construction process. At the same time, compared with the damaged and strengthened pier, the newly built pier is more reliable in quality, reducing the risk of later geological disasters.

[0076] (3) The installation of the new pier column 510 and the new capping beam 520 not only replaces the damaged part, but also improves the overall bearing capacity and durability of the bridge through optimized design. The setting of the post-cast space 521 allows concrete to be poured between the new capping beam 520 and the damaged pier column 30, further enhancing the integrity and stability of the structure.

[0077] As a preferred implementation, step S1 specifically includes the following steps:

[0078] 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;

[0079] S12, filling the expansion joint 210 between the beam body 20 and the abutment 10 with wooden wedges and wooden strips 224.

[0080] 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.

[0081] As a preferred implementation, step S2 specifically includes the following steps:

[0082] 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.

[0083] 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;

[0084] 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.

[0085] 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.

[0086] As a preferred implementation, step S5 specifically includes the following steps:

[0087] 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;

[0088] 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;

[0089] Specifically, Figure 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.

[0090] S53. A planar leveling assembly 560 is provided on the top of the new capping beam 520. Among them, the planar leveling assembly 560 includes a second chassis 561 and four lateral jacking units (not shown in the figure) arranged in a matrix. The bottom of the second chassis 561 is slidably arranged on the top surface of the new capping beam 520. The top of the second chassis 561 is fixedly connected to the old capping beam 40. Each lateral jacking unit includes a reaction frame 562 and a second jack 563. The reaction frame 562 is fixed to the top of the new capping 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 contacts the reaction frame 562, and the second end contacts the first chassis 541. Among them, the second chassis 561 is pushed by the second jack 563 to slide on the top surface of the new capping beam 520.

[0091] As a preferred embodiment, step S8 specifically includes the following steps:

[0092] S81. Weld the upper end of the vertical steel bar to the first embedded steel plate embedded at the bottom of the old capping beam 40 by arc welding at the bottom of the old capping beam 40, and weld the lower end of the vertical steel bar to the second embedded steel plate embedded at the top of the new capping beam 520 to form a rigid support, and then remove the planar leveling assembly 560.

[0093] S82. Pour concrete with the same grade as the new capping beam 520 into the post-cast space 521 to combine the new capping beam 520 with the old capping beam 40.

[0094] Specifically, after the old capping beam 40 is leveled and reset, weld the upper end of the vertical steel bar to the first embedded steel plate embedded at the bottom of the old capping beam 40 by arc welding at the bottom of the old capping beam 40, and weld the lower end of the vertical steel bar to the second embedded steel plate embedded at the top of the new capping beam 520 to form a rigid support, and then remove the planar leveling assembly 560. Pour concrete with the same grade as the new capping beam 520 into the post-cast space 521.

[0095] Further, step S9 specifically includes the following steps:

[0096] After the new capping beam 520 is combined with the old capping beam 40, loosen the bolts of the bearing 410 at the top of the damaged pier column 30 and remove the bearing 410 at the top of the damaged pier column 30.

[0097] Check whether the bearing padstone of the bearing 410 is damaged. If the bearing padstone of the bearing 410 is not damaged, use a grinding machine to remove and grind the sundries on the bearing padstone of the bearing 410, and then install the same type of pot bearing 410.

[0098] Further, if the bearing padstone 410 is damaged and cannot be used normally, the concrete of the padstone is chiseled off manually using a jackhammer, the embedded steel bars of the bearing padstone 410 are retained, a steel mesh is reinstalled, the bearing padstone 410 is re-poured, and then a pot bearing 410 of the same model is installed.

[0099] As a preferred example, the first chassis 541 is made of 20 I-beams, and the second chassis 561 is made of 36 I-beams.

[0100] The above are only the preferred embodiments of the present invention, and do not limit the protection scope of the present invention. Any equivalent structure or equivalent process transformation made by using the content of the specification and drawings of the present invention, or directly or indirectly applied in other related technical fields, shall be equally 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 bottom to top, the new cap beam is located directly below the old cap beam and a space is provided between the new cap beam and the old cap beam, the new pier column is arranged outside 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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