A telescopic device for cantilever support and a method for its replacement and modification

Abstract

A cantilever support telescopic device and a replacement and modification method, including a side beam special steel (2), characterized in that: the upper part of the side beam special steel (2) is cut off to form a side beam modification part (7) or the side beam special steel (2) is removed and replaced with a strip mounting seat, a left telescopic comb plate (9) is installed above the left anchor plate (8) through a connector, a right telescopic comb plate (11) is installed above the right anchor plate (10) through a connector, a middle beam modification seat (14) is movably set in the middle of the upper surface of the crossbeam (3), the middle beam modification seat (14) is perpendicular to the crossbeam (3), and an elastic support or sliding support is installed on the middle beam modification seat (14). The present invention has a reasonable structure, is easy to construct, and makes the maximum use of the original modular telescopic device anchor foundation. Only a small area of ​​the transition zone concrete needs to be removed, which greatly reduces the amount of construction.

Description

Technical Field

[0001] This invention relates to the transformation and upgrading of bridge expansion joints, and more particularly to a cantilever-supported expansion joint and its replacement and upgrading method, belonging to the field of road and bridge engineering technology. Background Technology

[0002] Modular bridge expansion joints are crucial connecting components between bridge beam ends. First invented by German engineer Maurer, modular bridge expansion joints account for over 80% of all bridge expansion joints worldwide and have been used in China for nearly 50 years. A modular bridge expansion joint consists of anchoring steel bars, edge beams with irregular shapes, center beams, crossbeams, waterproof rubber strips, displacement boxes, bearing supports, clamping supports, hangers, hinges, etc. Its basic principle is that core components such as hinges control the center beams, allowing them to achieve parallel, equally divided displacements in multiple modules, ranging from 0 to 8 millimeters.

[0003] Modular bridge expansion joints have complex structures, and their main defects include: inability to divide displacement equally, fracture of the central beam steel, oxidation and corrosion of hangers and hinges, downward bending of crossbeams, aging, deformation or detachment of bearing supports and clamping supports, etc.

[0004] Modular bridge expansion joints pose significant safety hazards due to fatigue damage and require immediate repair. Currently, all publicly available repair techniques, processes, methods, and structures involve completely removing the damaged modular bridge expansion joint and replacing it with a new one. However, since the repair and replacement of damaged modular bridge expansion joints are carried out in an operational environment, the quality and safety of the repair are constrained by environmental conditions. The fatigue resistance of the finished product upon acceptance will be compromised, and the fatigue life of the repaired structure will be shorter. This is especially problematic in areas with high traffic volume, where owners often require off-peak repairs and only a few hours of on-site work before reopening the road. Therefore, removing the old expansion joint and the damaged structure on-site is problematic. The process of replacing modular expansion joints involves a series of steps, including laying high-strength concrete, cleaning the trench, reinstalling and leveling the new expansion joint, straightening the embedded steel bars, applying epoxy resin, welding anchors, re-pouring high-strength concrete, curing, and cleaning up transported waste. These steps require a scientifically reasonable construction and curing period. Modular expansion joint repairs and replacements require a large volume of high-strength concrete. Generally, cost-effective C50 steel fiber concrete is used for repairs. If C50 steel fiber concrete is used for the repair or replacement of a modular expansion joint, the reasonable construction and curing period is typically 30 days, as the curing period for C50 steel fiber concrete is 28 days according to relevant national standards.

[0005] The scientifically sound construction and curing cycles are contradictory and mutually restrictive to the pressure of traffic, making a balance impossible. Furthermore, due to the limitation of the longitudinal distance between the two sides of the irregularly shaped steel beams of all modular expansion joints and the bridge, if they cannot be directly modified into comb-plate type expansion devices within this limited distance, statistical analysis reveals a common pattern: all modular expansion joints, if directly modified into comb-plate type expansion devices within the longitudinal distance between the two sides of the irregularly shaped steel beams, will have a 125mm difference in expansion distance gap according to relevant national industry standards. Direct modification within this range will encounter structural bottlenecks.

[0006] For a long time, repairing and replacing old and damaged modular expansion joints has required lengthy traffic disruptions. Besides dismantling and installation, the removal, pouring, and curing of concrete takes a significant amount of time, typically around a month, severely impacting traffic flow, especially on high-traffic sections. Currently, modifying modular expansion joints to install comb-plate expansion joints presents several technical obstacles. Installing them in slots where the modular expansion joints have been removed, using the traditional structure and installation method, results in insufficient installation space, significant concrete removal from the bridge abutment, high construction difficulty, and a long construction period. Furthermore, even when using traditional methods, comb-plate expansion joints suffer from poor structural strength and fatigue resistance, difficulty in adjusting the height and level of the comb plates during installation, and generate substantial waste and debris, making them less energy-efficient and environmentally friendly. These technical problems have remained unresolved. Summary of the Invention

[0007] The purpose of this invention is to address the technical bottlenecks in modifying existing modular telescopic devices into comb-plate telescopic devices. Repairing or replacing old or damaged modular telescopic devices requires prolonged traffic interruption. Traditional methods of installing comb-plate telescopic devices suffer from poor structural strength, inadequate fatigue resistance, difficulty in adjusting the height and level of the comb plates during installation, long construction cycles, and high construction difficulty. This invention provides a cantilever-supported telescopic device and its replacement method that offers a reasonable structure, convenient construction, and rapid modification. The cantilever-supported telescopic device boasts high structural strength and strong fatigue resistance, allows for easy on-site height and leveling, and ensures both support performance and telescopic displacement function. This significantly shortens the traffic interruption construction cycle and effectively solves the technical difficulties of modifying modular telescopic devices into comb-plate telescopic devices.

[0008] To achieve the above objectives, the technical solution of the present invention is: a cantilever support expansion joint device, comprising a side beam with irregular steel profile and a crossbeam. The side beam with irregular steel profile is anchored or pre-embedded and fixed on both sides of the bridge expansion joint groove. The upper part of the side beam with irregular steel profile is cut off to form a modified side beam component, or the side beam with irregular steel profile is removed and replaced with a strip mounting seat. A left anchor plate or a right anchor plate is fixedly installed on the outer end of the modified side beam component or on the strip mounting seat. The left anchor plate or the right anchor plate is welded and fixed to the anchoring steel bar located below. The upper part of the left anchor plate is connected by a connector. A left telescopic comb plate is installed above a right anchor plate via a connector; a lower stainless steel plate is fixedly installed at the bottom of the left telescopic comb plate near the expansion joint groove, and an upper stainless steel plate is fixedly installed at the bottom of the right telescopic comb plate near the expansion joint groove, with the lower and upper stainless steel plates stacked on top of each other; a middle beam modification seat is movably installed in the middle of the upper surface of the crossbeam, perpendicular to the crossbeam, and elastic or sliding supports are installed on the middle beam modification seat, with symmetrical waterstops on both sides.

[0009] Furthermore, the comb tooth structures of the left telescopic comb tooth plate and the right telescopic comb tooth plate are cross-fitted and have a certain telescopic gap, and the upper surface of the left telescopic comb tooth plate and / or the right telescopic comb tooth plate is provided with multiple overflow holes that penetrate the comb tooth plate.

[0010] Furthermore, the modified middle beam seat adopts a long strip-shaped channel steel structure or a U-shaped steel structure, with the opening of the channel steel structure or U-shaped steel structure facing upwards, and a height-adjustable component or epoxy resin layer is provided between the bottom of the modified middle beam seat and the elastic support component.

[0011] Furthermore, the connecting component includes a fixing screw, a support adjustment spring, and a fastening nut. The fixing screw is vertically fixed to the upper surfaces of the left and right anchor plates. The left and right telescopic comb plates have fixing holes corresponding to the fixing screw. The left telescopic comb plate is installed on the left anchor plate through the fixing holes, and the right telescopic comb plate is installed on the right anchor plate through the fixing holes. The fixing screw is fitted with a support adjustment spring, which is located at the bottom of the comb plate. The upper end of the fixing screw is fitted with a fastening nut for fixing the comb plate.

[0012] Furthermore, after removing part or all of the upper C-shaped or E-shaped structure of the side beam irregular steel, a side beam modification component is formed, while the lower part of the side beam irregular steel is retained.

[0013] Furthermore, one or more reinforcing ribs are fixedly installed on the abutment concrete on the outer side of the modified side beam using expansion bolts or rebar installation. The reinforcing ribs are welded and fixed to the anchor plate, and a transverse fixing member connected to the anchor plate is welded and fixed to the outer side of the root of the fixing screw.

[0014] Furthermore, high-strength concrete is poured into the grooves of the transition zone areas on the outer sides of the left and right telescopic comb plates, or high-strength concrete is poured into the grooves of the transition zone areas on the outer sides of the left and right telescopic comb plates and at the bottom of the left and right telescopic comb plates respectively.

[0015] Furthermore, the waterstop is made of an arc-shaped or corrugated metal plate and has a symmetrical structure. One side of the symmetrical waterstop is fixed to the middle beam modification seat, and the other side is fixed to the side beam modification component or anchor plate.

[0016] Furthermore, the overflow hole can be circular, elliptical, polygonal, or other shapes. The shape, size, and spacing of the overflow hole are determined according to the coverage area of ​​the comb plate and the concrete pouring area, the amount of expansion and contraction, and the overflow speed. After the overflow is completed, the overflow hole is filled with concrete mortar or a columnar metal of the same size as the overflow hole is inserted and fixed into the overflow hole.

[0017] A rapid modification construction method for modular expansion joints includes the following steps:

[0018] a. First, remove the waterproof unit, each middle beam steel and the original hinge structure in the modular expansion device, and clean up the sand, dust and debris as necessary, while retaining the side beam irregular steel located on both sides of the expansion joint groove.

[0019] b. Subsequently, the irregular steel of the side beam is cut off and modified. After cutting off part or all of the upper C-shaped or E-shaped structure of the irregular steel of the side beam, the modified side beam is formed. The transition zone concrete on the upper surface of the displacement box on the outside of the irregular steel of the side beam is removed on site.

[0020] c. Then place the middle beam modification seat in the middle of the crossbeam, and connect the two sides of the middle beam modification seat to the displacement box or bridge abutment through hinge 6 respectively.

[0021] d. Next, fix the waterstop to the middle beam modification seat. Fix the outer side of the middle beam modification seat to the side beam modification part or other fasteners. Fill the bottom of the middle beam modification seat with an epoxy resin layer of a certain thickness according to the required height adjustment, and install the elastic support in the middle beam modification seat at the upper end of the epoxy resin layer.

[0022] e. Anchor the anchor plates to the bridge abutments near the expansion joint slots, and weld the ends of the anchor plates to the modified side beams.

[0023] f. Then install the telescopic comb plate and the corresponding stainless steel plate at the bottom, so that the comb structure of the left telescopic comb plate and the right telescopic comb plate are cross-fitted and leave a certain telescopic gap.

[0024] g. Finally, pour high-strength concrete into the groove in the transition zone area outside the left and right telescopic comb plates, clean up the site debris, and open the road to traffic.

[0025] The beneficial effects of this invention are:

[0026] 1. This invention makes full use of the structure of the original modular expansion joint, requiring only adaptive cutting and modification of the upper part of the irregular steel of the side beam, while maximizing the use of the anchoring foundation of the original modular expansion joint, greatly reducing the amount of construction work.

[0027] 2. The present invention has an anchor plate fixedly installed on the bridge abutment at the outer end of the side beam modification component, and reinforced by reinforcing ribs to ensure the anchor is firm and reliable. In addition, a telescopic comb plate is installed above the anchor plate by means of a connector, which has high structural strength and improves the fixing effect of the comb plate.

[0028] 3. This invention uses a modified middle beam seat and hinges to achieve equally divided sliding displacement, and installs elastic support components on the modified middle beam seat, which can effectively provide sliding support for the suspended part of the comb plate, cleverly solving the technical problem of supporting the suspended part of the comb plate. Furthermore, symmetrical waterstops are installed on both sides of the modified middle beam seat, effectively solving the installation problem of the waterstops.

[0029] 4. The present invention has multiple overflow holes penetrating the comb plate on the upper surface of the comb plate. Excess concrete poured in the area where concrete is poured first or later can easily overflow upward from the overflow holes. The overflow holes also have an air venting function during the concrete flow process, which cleverly solves the problem of pouring too much or too little concrete. It is especially convenient for the construction of ultra-shallow expansion joints.

[0030] 5. This invention effectively solves the technical difficulties in modifying modular telescopic devices into comb-plate telescopic devices. It has a reasonable structure, is easy to construct, and the comb-plate telescopic device after rapid modification not only has high structural strength but also strong fatigue resistance. It can be easily adjusted and leveled on-site, and its support performance and telescopic displacement function can be guaranteed. It greatly shortens the construction cycle of traffic interruption and has broad application prospects. Attached Figure Description

[0031] Figure 1 This is a structural schematic diagram of a modular telescopic device in the prior art.

[0032] Figure 2 This is a schematic diagram of the structure of the present invention.

[0033] Figure 3 This is a top view of the present invention.

[0034] Figure 4 yes Figure 3Schematic diagram of the cross-sectional structure of AA.

[0035] Figure 5 This is a schematic diagram of the structure of the fixing screw part of the present invention.

[0036] Figure 6 This is a schematic diagram of the connector of the present invention.

[0037] In the diagram: 1. Central beam steel; 2. Side beam irregular steel; 3. Crossbeam; 4. Displacement box; 5. Anchoring steel bar; 6. Hinge; 7. Side beam modification component; 8. Left anchor plate; 9. Left telescopic comb plate; 10. Right anchor plate; 11. Right telescopic comb plate; 12. Lower stainless steel plate; 13. Upper stainless steel plate; 14. Central beam modification seat; 15. Modification seat fixing component; 16. Waterstop; 17. Overflow hole; 18. Fixing installation hole; 19. Fixing screw; 20. Transverse fixing component; 21. Support adjustment spring; 22. Fastening nut; 23. Reinforcing rib; 24. High-strength concrete. Detailed Implementation

[0038] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0039] See Figures 2 to 6 The present invention discloses a cantilever support telescopic device, comprising a side beam 2 and a crossbeam 3. The side beam 2 is anchored or pre-embedded and fixed on both sides of the bridge expansion joint groove. The device is characterized in that: the upper part of the side beam 2 is cut off to form a side beam modification component 7, or the side beam 2 is removed and replaced with a strip-shaped mounting seat. A left anchor plate 8 or a right anchor plate 10 is fixedly installed on the outer end of the side beam modification component 7 or on the strip-shaped mounting seat. The left anchor plate 8 or the right anchor plate 10 is welded and fixed to the anchoring steel bar 5 located below. A left telescopic comb plate 9 is installed above the left anchor plate 8 via a connector, and a left telescopic comb plate 9 is installed above the right anchor plate 10 via a connector. There is a right telescopic comb plate 11; a lower stainless steel plate 12 is fixedly installed at the bottom of the left telescopic comb plate 9 near the expansion joint groove, and an upper stainless steel plate 13 is fixedly installed at the bottom of the right telescopic comb plate 11 near the expansion joint groove. The lower stainless steel plate 12 and the upper stainless steel plate 13 are stacked on top of each other; a middle beam modification seat 14 is movably installed in the middle of the upper surface of the crossbeam 3. The middle beam modification seat 14 is perpendicular to the crossbeam 3. The two sides of the middle beam modification seat 14 are connected to the displacement box 4 or the bridge abutment through hinges 6 respectively. Elastic support or sliding support is installed on the middle beam modification seat 14. Waterstops 16 are installed on both sides of the middle beam modification seat 14.

[0040] The comb tooth structures of the left telescopic comb plate 9 and the right telescopic comb plate 11 are cross-fitted and have a certain telescopic gap. The upper surface of the left telescopic comb plate 9 and / or the right telescopic comb plate 11 is provided with a plurality of overflow holes 17 that penetrate the comb plate.

[0041] The modified middle beam seat 14 adopts a long strip-shaped channel steel structure or a U-shaped steel structure, with the opening of the channel steel structure or U-shaped steel structure facing upwards. A height-adjustable component or an epoxy resin layer is provided between the bottom of the modified middle beam seat 14 and the elastic support.

[0042] The connector includes a fixing screw 19, a support adjustment spring 21, and a fastening nut 22. The fixing screw 19 is vertically fixed to the upper surfaces of the left anchor plate 8 and the right anchor plate 10. The left telescopic comb plate 9 and the right telescopic comb plate 11 are provided with fixing mounting holes 18 corresponding to the fixing screw 19. The left telescopic comb plate 9 is installed on the left anchor plate 8 through the fixing mounting holes 18, and the right telescopic comb plate 11 is installed on the right anchor plate 10 through the fixing mounting holes 18. The support adjustment spring 21 is sleeved on the fixing screw 19 and is located at the bottom of the comb plate. The fastening nut 22 for fixing the comb plate is installed at the upper end of the fixing screw 19.

[0043] The upper C-shaped or E-shaped structure of the side beam 2 is partially or completely removed to form the side beam modification component 7, while the lower part of the side beam 2 is retained.

[0044] One or more reinforcing ribs 23 are fixed to the abutment concrete on the outer side of the modified side beam 7 by means of expansion bolts or rebar installation. The reinforcing ribs 23 are welded and fixed to the anchor plate. A transverse fixing member 20 connected to the anchor plate is welded and fixed to the outer side of the root of the fixing screw 19.

[0045] High-strength concrete 24 is poured into the groove of the transition zone area outside the left telescopic comb plate 9 and the right telescopic comb plate 11, or high-strength concrete 24 is poured into the groove of the transition zone area outside the left telescopic comb plate 9 and the right telescopic comb plate 11 and the bottom of the left telescopic comb plate 9 and the right telescopic comb plate 11 respectively.

[0046] The waterstop 16 is made of an arc-shaped or corrugated metal plate. The waterstop 16 has a left-right symmetrical structure. One side of the left-right symmetrical waterstop 16 is fixed to the middle beam modification seat 14, and the other side of the left-right symmetrical waterstop 16 is fixed to the side beam modification component 7 or the anchor plate.

[0047] The overflow hole 17 can be circular, elliptical, polygonal or other shapes. The shape, size and spacing of the overflow hole 17 are determined according to the coverage area of ​​the comb plate and the concrete pouring area, the amount of expansion and contraction and the overflow speed. After the overflow hole 17 is completed, the overflow hole 17 is filled with concrete mortar or a columnar metal of the same size as the overflow hole 17 is inserted and fixed in the overflow hole 17.

[0048] A method for replacing or modifying a modular telescopic device using cantilever support includes the following steps:

[0049] a. First, remove the waterproof unit, each middle beam steel 1 and the original hinge structure in the modular expansion device, and clean up the sand, dust and debris as necessary, while retaining the side beam irregular steel 2 located on both sides of the expansion joint groove.

[0050] b. Subsequently, the irregular steel 2 of the side beam is cut off and modified. After cutting off part or all of the upper C-shaped structure or E-shaped structure of the irregular steel 2 of the side beam, the modified side beam 7 is formed. The transition zone concrete on the upper surface of the displacement box 4 on the outside of the irregular steel 2 of the side beam is removed on site.

[0051] c. Then place the middle beam modification seat 14 in the middle position of the cross beam 3, and connect the two sides of the middle beam modification seat 14 to the displacement box 4 or the bridge abutment through the hinge 6 respectively.

[0052] d. Next, fix the waterstop 16 to the middle beam modification seat 14. The outer side of the middle beam modification seat 14 is fixed to the side beam modification part 7 or other fasteners. Fill the bottom of the middle beam modification seat 14 with an epoxy resin layer of a certain thickness as needed, and install the elastic support in the middle beam modification seat 14 at the upper end of the epoxy resin layer.

[0053] e. Anchor the anchor plates to the bridge abutment near the expansion joint groove, and weld the ends of the anchor plates to the side beam modification component 7.

[0054] f. Then install the telescopic comb plate and the corresponding stainless steel plate at the bottom, so that the comb structure of the left telescopic comb plate 9 and the right telescopic comb plate 11 are cross-fitted and leave a certain telescopic gap.

[0055] g. Finally, pour high-strength concrete 24 into the groove of the transition zone outside the left telescopic comb plate 9 and the right telescopic comb plate 11, and open the road to traffic after cleaning up the garbage on site.

[0056] See Figures 3 to 5 To address the construction cycle constraints of traditional modular bridge expansion joint maintenance and replacement, and the structural bottlenecks of the modified comb-plate type, extensive field investigations revealed the standard dimensional patterns of the irregular steel sections on the side beams of all modular bridge expansion joints. The C-shaped groove structure on the upper part of a single irregular steel section extends 40 mm longitudinally along the bridge, totaling 80 mm for two sections. On-site removal of the C-shaped structure on the upper part of the irregular steel section, along with chiseling away at least 45 mm of concrete from the transition zone on both sides of the irregular steel sections, freed up 170 mm of installation distance, far exceeding the 125 mm limitation. Furthermore, it was found that in most damaged modular bridge expansion joints, the transition zone high-strength concrete and displacement box areas were intact. Traditional maintenance methods require significant time to chisel out the old expansion joint, remove the transition zone high-strength concrete and displacement box, clean the grooves, apply epoxy reinforcement, re-pour high-strength concrete, cure, and clean up transport waste, consuming substantial manpower and resources and being extremely environmentally unfriendly.

[0057] The rapid conversion structure of the general-purpose modular expansion joint can, to the greatest extent possible, preserve the intact areas such as the side beam irregular steel, the high-strength concrete of the transition zone, and the displacement box. It only requires removing the middle beam steel, partially cutting off the side beam irregular steel, and chiseling away the transition zone concrete at least 45 mm wide and 80 mm deep on the outer sides of the two side beam irregular steels. Within the space corresponding to the transition zone at least 45 mm wide and 80 mm deep on the outer sides of the two side beam irregular steels, the modular expansion joint can be quickly converted into a comb-tooth plate expansion joint.

[0058] This invention provides a rapid on-site modification and repair solution for damaged modular telescopic devices. It eliminates the need to dismantle the original modular telescopic device, making full use of the existing structure, primarily utilizing the central beam 1, displacement box 4, and hinge 6. Simultaneously, the irregularly shaped side beams 2 are adaptively modified before installing the comb-tooth plate telescopic device described in this application. This improves the performance and durability of the telescopic device while enabling rapid repair and replacement, avoiding prolonged traffic disruptions. Therefore, this application solves a series of previously unresolved technical problems. The specific structure and principle are as follows:

[0059] The existing modular expansion joint mainly includes the following components: a central beam 1, side beams 2, crossbeams 3, displacement boxes 4, anchoring steel bars 5, and the original hinge structure. Displacement boxes 4 are fixedly installed on the left and right sides of two adjacent abutment beam ends. A crossbeam 3 is fixedly installed between two directly opposite displacement boxes 4. The crossbeams 3 on the left and right sides are on the same horizontal plane and parallel to each other. Multiple central beams 1 are vertically movable on the crossbeams 3, which are parallel to the side beams 2. Side beams 2 are fixedly installed at the abutment beam ends, and anchoring steel bars 5 are pre-embedded within the abutment beam ends. The side beams 2 are welded and fixed to the anchoring steel bars 5. A hinge 6 is installed between two opposite displacement boxes 4, connecting to each crossbeam 3. The hinge 6 ensures that each central beam 1 slides and expands at equal intervals on the crossbeams 3. Based on the physical properties of the hinge 6 itself, each of the middle beams 1 can slide equally on the crossbeam 3, and the middle beam 1 located in the middle will always be in the middle position of the expansion joint groove no matter how it slides.

[0060] When existing modular expansion joints need to be replaced due to fatigue damage caused by long-term use, it is not necessary to dismantle the central beam 1, crossbeam 3, displacement box 4, hinge 6, and other accessory structures. Only the waterproof unit, central beam 1, and the original hinge structure need to be removed. The side beam irregular steel 2 needs to be adapted by cutting and modifying it. The upper part of the side beam irregular steel 2 is cut off to form the side beam modification component 7. Specifically, part or all of the upper C-shaped or E-shaped structure of the side beam irregular steel 2 is cut off to form the side beam modification component 7, while the lower part of the side beam irregular steel 2 is retained. This maximizes the use of existing usable structures, reduces maintenance time, and improves maintenance efficiency. Simultaneously, at least 100 mm wide transition zone concrete on the side of the side beam irregular steel 2 closest to the road surface is chiseled away on-site to provide sufficient installation and construction space for the comb-plate expansion joint device of this application. Alternatively, the side beam irregular steel 2 can be completely removed, and a new strip mounting seat can be installed. The strip mounting seat is anchored to the bridge abutment end face, and its function is the same as that of the side beam modification component 7.

[0061] A left anchor plate 8 or a right anchor plate 10 is fixedly installed on the outer end of the side beam modification component 7 or on the strip mounting base. The left anchor plate 8 and the right anchor plate 10 are made of steel plates of a certain thickness and serve as the bottom mounting base for installing the comb plate. The left anchor plate 8 and the right anchor plate 10 can be directly welded to the anchoring steel bar 5, or one or more reinforcing bars 23 can be fixed to the abutment concrete on the outer side of the side beam modification component 7 by means of expansion bolts or rebar installation, and the reinforcing bars 23 are welded to the anchor plate. Alternatively, the anchoring steel bar 5 can be welded together with the reinforcing bars 23 for additional welding, which can ensure the anchoring is firm and reliable, thereby improving the installation and fixing effect of the comb plate.

[0062] One or more rows of fixing screws 19 are vertically fixed to the upper surfaces of the left anchor plate 8 and the right anchor plate 10. A transverse fixing member 20, connected to the anchor plate, is welded to the outer side of the root of each fixing screw 19. The transverse fixing member 20 can be a long steel bar or a strip steel plate, welded to the upper surface of the anchor plate and simultaneously welded to the root of the fixing screw 19 to improve the stability of the fixing screw 19. Fixing holes 18 corresponding to the fixing screws 19 are provided on the left telescopic comb plate 9 and the right telescopic comb plate 11. The left telescopic comb plate 9 is installed on the left anchor plate 8 through the fixing holes 18 and the fixing screws 19, and the right telescopic comb plate 11 is installed on the right anchor plate 10 through the fixing holes 18 and the fixing screws 19. A fastening nut 22 for fixing the comb plate is installed at the upper end of each fixing screw 19. A support adjustment spring 21 is fitted on the fixing screw 19. The support adjustment spring 21 is supported on the lower surface of the comb plate, which can provide a certain support for the comb plate during installation and leveling. At the same time, the elasticity of the support adjustment spring 21 can also play a certain role in preventing loosening.

[0063] The comb teeth of the left telescopic comb plate 9 and the right telescopic comb plate 11 are cross-fitted and have a certain telescopic gap, allowing them to slide relative to each other for a certain length to meet the requirements of bridge expansion and contraction. Additionally, a lower stainless steel plate 12 is fixedly installed at the bottom of the left telescopic comb plate 9 near the expansion joint groove, and an upper stainless steel plate 13 is fixedly installed at the bottom of the right telescopic comb plate 11 near the expansion joint groove. The lower stainless steel plate 12 and the upper stainless steel plate 13 are stacked vertically, providing a sliding friction surface with low friction while also providing some support.

[0064] The present invention provides a movable middle beam modification seat 14 at the center of the upper surface of the crossbeam 3. The middle beam modification seat 14 is perpendicular to the crossbeam 3 and can slide on the upper surface of the middle beam 1. Both sides of the middle beam modification seat 14 are connected to the displacement box 4 or the bridge abutment via hinges 6. Elastic supports or sliding supports are installed on the middle beam modification seat 14, which can effectively provide sliding support for the suspended part of the comb plate, improving the load-bearing capacity. Simultaneously, an epoxy resin layer of a certain thickness is injected into the bottom of the middle beam modification seat 14 according to the required height, and elastic supports are installed inside the middle beam modification seat 14 at the upper end of the epoxy resin layer. This cleverly solves the technical problem of supporting the suspended part of the comb plate. Furthermore, symmetrical waterstops 16 are installed on both sides of the middle beam modification seat 14, effectively solving the installation problem of the waterstops. The sliding support structure has at least the following three implementation methods:

[0065] Example 1: The middle beam modification seat 14 adopts a channel steel structure with the opening of the channel steel facing upward. The bottom of the middle beam modification seat 14 is directly welded and fixed to the upper surface of the middle beam steel 1. An elastic rubber strip with a certain height is inserted into the groove of the middle beam modification seat 14. The upper end of the elastic rubber strip is higher than the uppermost end of the middle beam modification seat 14, and the upper end of the cross-section of the elastic rubber strip is set as an arc to better meet the sliding support of the comb plate.

[0066] Example 2: The middle beam modification seat 14 adopts a channel steel structure with the opening of the channel steel facing upward. The middle beam modification seat 14 is welded and fixed to the upper surface of the middle beam steel 1 by the modification seat fixing part 15. The modification seat fixing part 15 is supported by small steel plates or other anchors. An elastic rubber strip with a certain height is inserted into the groove of the middle beam modification seat 14. The upper end of the elastic rubber strip is higher than the uppermost end of the middle beam modification seat 14, and the upper end of the cross section of the elastic rubber strip is set as an arc to better meet the sliding support of the comb plate.

[0067] Example 3: The middle beam modification seat 14 adopts a U-shaped steel structure with the opening of the U-shaped steel structure facing upward. The bottom of the middle beam modification seat 14 is directly welded and fixed to the upper surface of the middle beam steel 1. Rolling bearings or cylindrical rollers are installed in the groove of the U-shaped steel structure. The upper rim of the rolling bearings or cylindrical rollers contacts the bottom surface of the comb plate or stainless steel plate, which can meet the sliding support of the comb plate.

[0068] The waterstop 16 is made of an arc-shaped or corrugated metal plate. It features a symmetrical structure consisting of two parts. One side of the symmetrical waterstop 16 is fixed to the central beam modification seat 14, and the other side is fixed to the side beam modification component 7 or the anchor plate. The waterstop 16 can deform synchronously with the movement of the central beam modification seat 14, ensuring good waterproofing performance.

[0069] This invention uses hinges 6 of the same size and structure to install the center beam modification seat 14 in the middle position. Based on the characteristic of hinges 6 dividing the displacement equally, the center beam modification seat 14 remains in the middle position during expansion and contraction. If there is an odd number of original center beam steels 1, the center beam steel 1 in the middle position can be retained, and its upper part can be cut off and modified before fixing the center beam modification seat 14. The width of the center beam modification seat 14, and the width of the hinges 6 in the folded state, must be less than the minimum width between the side beam modification parts 7 in the contracted state. The number of original center beam steels can be calculated using the following formula: Expansion / Contraction Amount ÷ 80 - 1 = Number of Center Beam Steels.

[0070] In addition, to address the issue of excessive or insufficient concrete pouring and to enable rapid construction of ultra-shallow expansion joints, this invention provides multiple overflow holes 17 penetrating the upper surfaces of the left and right expansion comb plates 9 and 11. Due to the poor fluidity of concrete, the multiple overflow holes 17, while ensuring the overall structural strength of the comb plates, ensure that excess concrete in each area can overflow from the nearby overflow holes 17, cleverly solving the problem of excessive or insufficient concrete pouring. This is particularly convenient for the construction of ultra-shallow expansion joints. Furthermore, the overflowing concrete fills the overflow holes 17. The solidified concrete within the overflow holes 17 is columnar, increasing the contact area between the comb plates and the concrete, improving the shear resistance of the comb plates, and extending the fatigue life of the bridge expansion joint. Furthermore, after the concrete in the overflow hole 17 solidifies, its surface is a concrete layer, and its frictional resistance is much higher than that of the steel comb plate. This can effectively improve the grip of car tires, prevent vehicle slippage, and improve driving safety. In addition, during the flow of concrete under the comb plate, the overflow hole 17 of this invention can also act as a vent hole to expel air, providing favorable conditions for the concrete to quickly fill the pouring area.

[0071] Another function of the overflow hole 17 is to facilitate core drilling inspection before acceptance and opening to traffic. In traditional comb plates without overflow holes 17, core sampling cannot be performed after installation because the concrete in the concealed area under the comb plate cannot be drilled. However, in this invention, because the overflow hole 17 is provided, and there is no thick comb plate steel plate covering the overflow hole 17, core sampling is greatly facilitated. Core sampling can be achieved simply by drilling at the location of the overflow hole 17, which is convenient and quick. After sampling, the sampling hole can be sealed with high-strength concrete.

[0072] After the overflow hole 17 is filled with concrete mortar, a columnar metal of the same size as the overflow hole 17 can be inserted and fixed into the overflow hole 17. The columnar metal can be the columnar metal scrap left when cutting and processing the overflow hole 17. The columnar metal scrap can be inserted into the overflow hole 17 and welded and fixed. The installation is very convenient.

[0073] The construction steps for modifying and replacing a modular expansion joint are as follows: First, remove the waterproof unit, each central beam steel 1, and the original hinge structure from the modular expansion joint, and clean up the sand, dust, and debris as necessary, retaining the side beam irregular steel 2 located on both sides of the expansion joint groove. Then, modify the side beam irregular steel 2 by removing part or all of the upper C-shaped or E-shaped structure to form the side beam modification component 7. Remove the transition zone concrete on the upper surface of the displacement box 4 on the outside of the side beam irregular steel 2 on site. Next, place the central beam modification seat 14 in the middle of the crossbeam 3, and connect both sides of the central beam modification seat 14 to the displacement box 4 or bridge abutment via hinges 6. Next, the waterstop 16 is fixed to the middle beam modification seat 14. The outer side of the middle beam modification seat 14 is fixed to the side beam modification component 7 or other fasteners. An epoxy resin layer of a certain thickness is poured into the bottom of the middle beam modification seat 14 according to the required height adjustment, and an elastic support is installed inside the middle beam modification seat 14 at the upper end of the epoxy resin layer. Anchor plates are anchored to the bridge abutments near the expansion joint groove, and the ends of the anchor plates are welded to the side beam modification component 7. Then, the expansion comb plates and corresponding lower stainless steel plates are installed, so that the comb structure of the left expansion comb plate 9 and the right expansion comb plate 11 cross-fits and leaves a certain expansion gap. Finally, high-strength concrete 24 is poured into the groove in the transition zone area outside the left expansion comb plate 9 and the right expansion comb plate 11. After cleaning up the site debris, traffic is opened.

[0074] The above description is a further detailed explanation of the present invention in conjunction with specific embodiments. It should not be considered that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, any simple modifications and substitutions made without departing from the concept of the present invention should be considered to fall within the protection scope of the present invention.

Claims

1. A cantilever supported telescopic device comprising a side beam special-shaped steel (2) and a cross beam (3), the side beam special-shaped steel (2) is fixedly arranged on both sides of the bridge expansion joint slot, characterized in that: The upper part of the side beam special-shaped steel (2) is cut to form a side beam reforming piece (7), or the side beam special-shaped steel (2) is removed and replaced by a strip-shaped mounting seat, a left anchor plate (8) or a right anchor plate (10) is fixedly arranged on the outer side end of the side beam reforming piece (7) or the strip-shaped mounting seat, the left anchor plate (8) or the right anchor plate (10) is welded and fixed with the anchor steel bars (5) located below, the upper side of the left anchor plate (8) is provided with a left telescopic comb plate (9) through a connecting piece, the upper side of the right anchor plate (10) is provided with a right telescopic comb plate (11) through a connecting piece, the bottom of the left telescopic comb plate (9) is fixedly provided with a lower stainless steel plate (12) close to the side of the expansion joint slot, the bottom of the right telescopic comb plate (11) is fixedly provided with an upper stainless steel plate (13) close to the side of the expansion joint slot, the lower stainless steel plate (12) and the upper stainless steel plate (13) are arranged in a vertically stacked manner, the upper surface of the cross beam (3) is movably provided with a middle beam reforming seat (14) in the middle part, the middle beam reforming seat (14) is perpendicular to the cross beam (3), the middle beam reforming seat (14) is provided with an elastic support or a sliding support, the middle beam reforming seat (14) is provided with two symmetric water stops (16), the comb tooth structures of the left telescopic comb plate (9) and the right telescopic comb plate (11) are cross matched and leave a certain expansion gap, and a plurality of overflow holes (17) penetrating through the comb plate are formed in the upper surface of the left telescopic comb plate (9) and / or the right telescopic comb plate (11).

2. A cantilever supported retraction device according to claim 1, wherein: The middle beam reforming seat (14) adopts a long strip-shaped channel steel structure or a U-shaped steel structure, the opening of the channel steel structure or the U-shaped steel structure faces upward, and a height-adjustable piece or an epoxy resin layer is arranged between the bottom of the middle beam reforming seat (14) and the elastic support.

3. A cantilevered supported telescoping device as defined in claim 1, wherein: The connecting piece comprises a fixed screw rod (19), a support adjusting spring (21) and a fastening nut (22), the fixed screw rod (19) is vertically fixed on the upper surface of the left anchor plate (8) and the right anchor plate (10), the left telescopic comb plate (9) and the right telescopic comb plate (11) are provided with fixed mounting holes (18) corresponding to the fixed screw rod (19), the left telescopic comb plate (9) is mounted on the left anchor plate (8) through the fixed mounting hole (18), the right telescopic comb plate (11) is mounted on the right anchor plate (10) through the fixed mounting hole (18), the support adjusting spring (21) is sleeved on the fixed screw rod (19) and located at the bottom of the comb plate, and the fastening nut (22) for fixing the comb plate is mounted on the upper end of the fixed screw rod (19).

4. A cantilevered supported telescoping device as defined in claim 1, wherein: The upper part of the side beam special-shaped steel (2) is cut to form a side beam reforming piece (7), or the side beam special-shaped steel (2) is removed and replaced by a strip-shaped mounting seat, a left anchor plate (8) or a right anchor plate (10) is fixedly arranged on the outer side end of the side beam reforming piece (7) or the strip-shaped mounting seat, the left anchor plate (8) or the right anchor plate (10) is welded and fixed with the anchor steel bars (5) located below, the upper side of the left anchor plate (8) is provided with a left telescopic comb plate (9) through a connecting piece, the upper side of the right anchor plate (10) is provided with a right telescopic comb plate (11) through a connecting piece, the bottom of the left telescopic comb plate (9) is fixedly provided with a lower stainless steel plate (12) close to the side of the expansion joint slot, the bottom of the right telescopic comb plate (11) is fixedly provided with an upper stainless steel plate (13) close to the side of the expansion joint slot, the lower stainless steel plate (12) and the upper stainless steel plate (13) are arranged in a vertically stacked manner, the upper surface of the cross beam (3) is movably provided with a middle beam reforming seat (14) in the middle part, the middle beam reforming seat (14) is perpendicular to the cross beam (3), the middle beam reforming seat (14) is provided with an elastic support or a sliding support, the middle beam reforming seat (14) is provided with two symmetric water stops (16), the comb tooth structures of the left telescopic comb plate (9) and the right telescopic comb plate (11) are cross matched and leave a certain expansion gap, and a plurality of overflow holes (17) penetrating through the comb plate are formed in the upper surface of the left telescopic comb plate (9) and / or the right telescopic comb plate (11).

5. A cantilevered supported telescoping device as defined in claim 1, wherein: ​ 6. A cantilevered supported telescoping device as defined in claim 1, wherein: The transition zone groove on the outer side of the left and right telescopic comb tooth plates (9) and (11) is poured with high-strength concrete (24), or the transition zone groove on the outer side of the left and right telescopic comb tooth plates (9) and (11) and the bottom of the left and right telescopic comb tooth plates (9) and (11) are respectively poured with high-strength concrete (24).

7. A cantilevered supported telescoping device as defined in claim 1, wherein: The water stop belt (16) is made of an arc-shaped or corrugated metal plate, and is in a whole structure or a left-right symmetrical structure. One side of the water stop belt (16) in the whole structure is fixed on the left side beam reforming part (7) or anchor plate, and the other side of the water stop belt (16) in the whole structure is fixed on the right side beam reforming part (7) or anchor plate. One side of the water stop belt (16) in the left-right symmetrical structure is fixed on the middle beam reforming seat (14), and the other side of the water stop belt (16) in the left-right symmetrical structure is fixed on the side beam reforming part (7) or anchor plate.

8. A cantilevered supported telescoping device as defined in claim 1, wherein: The overflow hole (17) is circular, oval or polygonal, and the shape, size and spacing of the overflow hole (17) are determined according to the coverage area size, telescopic size and overflow speed of the comb tooth plate and the concrete pouring area. After the overflow is completed, the overflow hole (17) is filled with concrete mortar or a columnar metal with the same size as the overflow hole (17) is inserted into the overflow hole (17).

9. A method for replacing a modular expansion joint with a cantilever support expansion joint according to claim 6, comprising the following steps: a. The existing modular expansion joint mainly comprises the following main components: middle beam steel (1), side beam special-shaped steel (2), cross beam (3), displacement box (4), anchor steel bar (5) and hinge (6). Displacement boxes (4) are fixedly arranged on both sides of the adjacent two abutment beam ends. Cross beams (3) are fixedly arranged between the two displacement boxes (4) facing each other. The cross beams (3) on the left and right sides are located on the same horizontal plane and are parallel to each other. A plurality of middle beam steels (1) are vertically movably arranged on the cross beam (3). The cross beam (3) is arranged in parallel with the side beam special-shaped steel (2). The side beam special-shaped steel (2) is fixedly arranged on the abutment beam end. The anchor steel bar (5) is pre-buried in the abutment beam end. The side beam special-shaped steel (2) is welded and fixed with the anchor steel bar (5). The hinge (6) is installed between the two displacement boxes (4) opposite to each other, and the hinge (6) is connected with each cross beam (3). During the reform, the waterproof unit, each middle beam steel (1) and the original hinge structure in the modular expansion joint are removed first, and the necessary sand, dust and debris are cleaned. The side beam special-shaped steel (2) located on both sides of the expansion joint groove is retained; b. Then, the side beam special-shaped steel (2) is cut and reformed. The upper C-shaped structure or E-shaped structure of the side beam special-shaped steel (2) is cut partially or entirely to form a side beam reforming part (7). The transition zone concrete on the upper surface of the displacement box (4) outside the side beam special-shaped steel (2) is removed on site. c. Then the middle beam transformation seat (14) is placed in the middle of the cross beam (3), and the two sides of the middle beam transformation seat (14) are connected with the displacement box (4) or the abutment through the hinge (6) respectively; d. Then the water stop belt (16) is fixed on the middle beam transformation seat (14), the outer side of the middle beam transformation seat (14) is fixed on the side beam transformation part (7) or other fixed parts, the height of the bottom of the middle beam transformation seat (14) is filled with a certain thickness of epoxy resin layer according to the need, and the elastic support is installed in the middle beam transformation seat (14) at the upper end of the epoxy resin layer; e. The anchor plates are respectively anchored on the abutments near the expansion joint slots, and the end portions of the anchor plates are welded and fixed with the side beam transformation part (7); f. Then the expansion comb plate and the corresponding lower stainless steel plate are respectively installed, so that the comb tooth structures of the left expansion comb plate (9) and the right expansion comb plate (11) are cross matched and a certain expansion gap is left; g. Finally, the high-strength concrete (24) is cast in the slot of the transition zone of the left expansion comb plate (9) and the right expansion comb plate (11) on the outer side, and the traffic is opened after the site garbage is cleaned.

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