Tail structure of clamping plate for rapid seamless reconstruction of existing bridge and reconstruction construction method
By setting up an approach slab tail structure at the bridge-road junction, including approach slabs, ground beams, and steel cover plates, the problem of expansion joint defects in existing bridges was solved, enabling rapid and seamless reconstruction of bridges, reducing construction costs and traffic impact, and improving the performance and safety of bridges.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- SHANGHAI URBAN CONSTRUCTION DESIGN & RESEARCH INSTITUTE (GROUP) CO LTD
- Filing Date
- 2023-11-14
- Publication Date
- 2026-07-21
AI Technical Summary
Existing bridges suffer from problems such as bridge approach slab ...
A bridge approach slab tail structure is installed at the road-bridge junction, including an approach slab, a ground beam, and a steel cover plate. By creating a gap between the approach slab and the ground beam and filling it with rubber elastic foam material, asphalt mixture and steel-plastic geogrid are laid, and a rubber elastic transition plate is installed to achieve seamless bridge reconstruction.
Shorten the construction period, reduce project costs, minimize environmental and traffic impacts, ensure that the performance and durability of the seamless asphalt pavement are no less than those of the adjacent roads, and improve the service life and safety of bridges.
Smart Images
Figure CN117431866B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of existing bridge reconstruction technology, specifically to the rapid and seamless reconstruction of existing bridges, and to a method for constructing and reconstructing the approach slab tail structure. Background Technology
[0002] Bridge expansion joints are bridge expansion devices installed to eliminate displacement caused by changes in the length of the bridge beam due to temperature variations, and to maintain a smooth driving experience. Their function is to regulate the displacement between the superstructure and the connections between the superstructures caused by vehicle load environmental characteristics and the physical properties of bridge construction materials.
[0003] Bridge expansion joints transfer the load acting on them to the main bridge structure. Because they are constantly exposed to the atmosphere in harsh environments, they are among the most vulnerable and difficult-to-maintain components of the bridge structure. During construction and operation, they are affected by loads, environment, and material aging. Even slight defects or deficiencies in design, construction techniques, and welding quality can reduce driving comfort and affect vehicle lifespan.
[0004] Expansion joints and bearings in bridge structures are non-full-life components, prone to defects and requiring ongoing maintenance, which increases maintenance frequency and costs. Expansion joints, in particular, affect driving comfort and environmental noise, and their repair significantly disrupts traffic. To ensure bridge operational safety, it is essential to fundamentally eliminate defects in bridge expansion joints, reduce maintenance workload and costs, ensure safety, and extend the bridge's service life.
[0005] In existing technologies, the main defects of bridge expansion joints manifest in the following aspects:
[0006] 1. Vehicles bouncing at bridgeheads and bridge expansion joints affect road surface smoothness and comfort;
[0007] The term "stepping" at bridgeheads and expansion joints refers to the presence of steps at the bridgeheads and expansion joints of highways. These steps cause numerous inconveniences and even significant hazards to vehicles, and can be summarized as follows:
[0008] (1) It affects driving safety and comfort. The reason is that when a vehicle passes over a steep slope at the bridgehead, it will cause discomfort and bumpy ride, or even violent vibration and jumping. Uneven settlement will cause lateral swaying and even lead to driving accidents.
[0009] (2) Reduced road capacity; when vehicles pass over steep slopes at the bridgehead, drivers are forced to brake and slow down, which can easily cause traffic congestion, indirectly reduce social benefits, and lower people's overall evaluation of the road.
[0010] (3) Impact damage to bridges and vehicles; the impact force generated by the vehicle jumping causes additional impact loads on bridges and roadbeds, which accelerates the damage to abutments, bridge approach slabs, especially supports and expansion joints, and also causes wear and tear on vehicle parts, tires, etc., reducing the service life of vehicles.
[0011] (4) It creates a vicious cycle of roadbed and pavement damage; because the bouncing of vehicles in turn aggravates the impact on the pavement, further exacerbating the pavement damage, and the interaction between them forms a vicious cycle. Over time, asphalt pavements will experience an expansion of the damaged area, and the defects such as wave-like, cracked and subsidence will worsen, while cement concrete pavements will experience phenomena such as broken slabs, edge chipping, and mud pumping.
[0012] (5) Increase highway maintenance costs; as mentioned above, bridge approach slabs affect bridges, roads and vehicles. Therefore, highway maintenance departments need to allocate certain funds for treatment and increase maintenance investment. Moreover, the treatment will affect road traffic to varying degrees.
[0013] 2. Damaged expansion joints are a source of corrosion, reducing the service life of bridges;
[0014] Bridge expansion joints are typically installed within the clear width of the bridge deck, bending vertically upwards by 5cm at the curb.
[0015] In routine inspections of traditional jointed bridges, water seepage often occurs at the ends and outer sides of the expansion joints. Water on the bridge surface (especially snowmelt containing de-icing agents accumulated after snow removal in winter) seeps into the web of the main beam and the ends of the abutment (pier) cap beam, causing erosion and damage to the concrete of the beam body and the ends of the cap beam, affecting the durability of the structure.
[0016] 3. The noise level is higher than that of the roadbed and pavement sections, usually exceeding 30% of that of the roadbed and pavement sections, which affects human health;
[0017] According to data from the article "Measurement and Influencing Factor Analysis of Bridge Expansion Joint Noise" published in Environment and Development in 2017 by Shi Linze et al., combined with the sound environment quality standards, the acceptable sound environment for the human body is 60 to 70 dB, while the noise generated by vehicles passing over bridge expansion joints reaches 80 to 100 dB, which requires sufficient attention.
[0018] 4. During the operation and maintenance phase, carbon emissions account for a high proportion, usually more than one-third;
[0019] According to the publicly available literature report "Research on Carbon Emissions of Bridges with Different Structural Materials in Their Life Cycle" published by Xu Shuang of Wuhan University of Technology in 2012, the carbon emissions generated by the maintenance of expansion joints are the largest during the entire maintenance and operation phase of a bridge, accounting for more than one-third of the total carbon emissions in the entire phase.
[0020] 5. Easily damaged and difficult to repair: It affects traffic flow and safety, and the indirect costs are high and increasing day by day (daily cleaning of cracks and frequent maintenance).
[0021] According to the defect statistics in the inspection report of 40 bridges on a highway in Shanghai, 100% of the expansion joints of both elevated bridges and small and medium-sized bridges on the ground have defects.
[0022] For example, the expansion joints of a certain hub's one vertical and two horizontal elevated bridge were severely damaged and could no longer be used normally after only four years of operation. In July 2014, the Shanghai Municipal Road Administration Bureau commissioned our institute to prepare a renovation plan. The lowest cost plan included nearly 10 million yuan for the renovation of the expansion joints in a single project, without including the costs of related measures during maintenance and the adverse effects on the structure and society.
[0023] Furthermore, damage to expansion joints can lead to vehicles losing control after a collision, causing traffic accidents and posing a threat to society. For example, in 2020, a shocking traffic accident occurred on a triangular section of a highway due to damage to an expansion joint, and the highway maintenance department ultimately provided full compensation.
[0024] With societal development, higher demands are being placed on bridge design. It is necessary to consider not only safety, applicability, economy, and aesthetics, but also to minimize future maintenance, or even achieve "zero maintenance." Bridge maintenance should not have a significant impact on traffic operations, and the direct and indirect costs of bridge construction and maintenance should be minimized.
[0025] Regarding the main problems with bridge expansion joints mentioned above, there are two approaches to solving them in the existing technology: one is to design and produce expansion devices with better quality and performance; the other is to reduce or eliminate expansion devices as much as possible. The concept of bridges without expansion devices is based on the latter.
[0026] Bridges without expansion joints reduce bridge maintenance during the operational period and lower total life-cycle costs. Integral bridges, by eliminating expansion joints and supports (note: bridges retaining supports but eliminating expansion joints are called semi-integral bridges), connect the abutment slab to the main beam as a single unit (temperature deformation of the beam is transferred to the end of the abutment slab where it connects to the roadbed and pavement). This completely eliminates the negative impacts of expansion joints and supports, fundamentally solving problems such as approach slab settlement, long-term maintenance, and periodic replacement caused by damage to bridge expansion joints. Furthermore, they offer a comfortable, smooth ride with low noise. This improves the quality of the roadbed and pavement, enhances the surrounding environment, and effectively improves the bridge's seismic resistance, thus extending its service life and yielding significant economic and social benefits.
[0027] This technology has been widely and successfully applied in developed regions abroad (tens of thousands of units). Its main advantages are as follows:
[0028] ① Significantly reduces backboard bounce: Leveling is easily achieved, resulting in a comfortable ride without bounce;
[0029] ② Noise reduction and environmental protection: Noise reduction >30%;
[0030] ③ Low maintenance: Easy to maintain, significantly reducing costs, time and complexity, and its performance and durability are no less than those of adjacent roads;
[0031] ④ Low impact: Reduces the impact of maintenance on surrounding traffic and the environment;
[0032] ⑤ Low carbon: Carbon emissions from maintenance are reduced by more than 30%;
[0033] ⑥ No increase in total life cycle cost: Although the initial investment is slightly higher than that of traditional processes, the total life cycle cost is the lowest;
[0034] ⑦ Good durability: No leakage or corrosion, which helps extend the service life of the bridge;
[0035] ⑧ Good safety performance: Increased redundancy enhances seismic resistance.
[0036] However, a large number of bridges worldwide are still built using traditional techniques, and the problems with their expansion joints will not disappear with the advent of new technologies. The issues caused by the shortcomings of traditional techniques continue to arise and evolve. For example, among the approximately 710,000 highway bridges in service in China, small and medium-sized bridges with a total length of less than 100 meters account for about 93%. Achieving zero or minimal expansion joints in existing bridges would have significant economic and social implications.
[0037] Traditional jointed bridges typically have approach slabs installed behind the abutments. Approach slabs, also known as approach ramps, are an important component of jointed bridges and bridges without expansion joints.
[0038] Using approach slabs offers numerous advantages. The approach slab effectively spans the abutment and the backfill, reducing the impact of vehicles on the backfill and the passive earth pressure on the abutment. If the approach slab is long enough, it can completely eliminate the backfill earth pressure caused by vehicles. When the roadbed settles, the approach slab acts as a transition between the bridge and the adjacent roadbed, resulting in smoother traffic and reducing the impact force on the bridge. Approach slabs also provide a more even load distribution at the bridge ends, reducing damage to the abutments, especially from overloaded vehicles. Furthermore, approach slabs with drainage systems help regulate roadbed drainage, preventing rainwater erosion of the backfill or damage caused by freezing and thawing of the backfill due to water accumulation.
[0039] In bridges without expansion joints, part of the temperature deformation is absorbed by the elastic deformation of the main beam, while the other part is transferred to the junction of the approach slab and the roadbed / pavement. In other words, the approach slab is an important component for transferring temperature displacement in bridge structures.
[0040] In existing technologies, closed expansion joints that can accommodate repeated expansion and contraction are typically installed at the expansion joints of the approach slab. These expansion joints must prevent rainwater from entering and wetting the roadbed. Simultaneously, contraction joints are installed in the roadbed and pavement to release compressive stress. In other words, the elongation of the concrete approach slab will generate significant compressive stress in the roadbed and pavement.
[0041] In the seamless reconstruction of existing bridges, the bridge technology without expansion joints changes the system of jointed bridges by integrating the bridge superstructure with the approach slab structure. It extends the continuous length of the bridge structure and transfers the amount of thermal expansion and contraction deformation to and burys it deep under the asphalt subgrade and pavement area at the road-bridge junction, thus achieving the goal of eliminating expansion joints.
[0042] If no measures are taken to address the increased temperature-induced deformation and gaps beneath the asphalt pavement at the road-bridge junction, reflective cracks are likely to form on the asphalt pavement. However, if a new bridge approach slab layout and combined caisson scheme without expansion joints are adopted, the existing approach slabs and the underlying roadbed must be completely demolished before being reinstalled and poured. This will increase the project cost and construction period, and will also have a significant impact on the environment and current traffic conditions, especially for roadbeds and pavements with high environmental requirements and heavy traffic.
[0043] Therefore, under the premise of ensuring that the performance and durability of seamless asphalt pavement are no less than those of adjacent roads, how to accelerate the seamless reconstruction of bridges during their service life, reduce project costs and construction cycle, and minimize the impact on the environment and existing traffic has become a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention
[0044] In view of the above-mentioned deficiencies of the prior art, the present invention provides a slab tail structure and reconstruction construction method for the rapid and seamless reconstruction of existing bridges. The purpose is to provide a slab tail structure and corresponding reconstruction construction method for the rapid, unimpeded, low-impact, and low-cost seamless reconstruction of existing bridges. Under the premise of ensuring that the performance and durability of the seamless asphalt pavement are no less than those of the adjacent roads, the invention improves the speed of seamless reconstruction of bridges during their service life, reduces project costs and construction period, and reduces the impact on the environment and existing traffic.
[0045] To achieve the above objectives, the present invention discloses a slab tail structure for the rapid and seamless reconstruction of existing bridges, including a slab set at the road-bridge junction and a ground beam located between the slab and the old roadbed and pavement.
[0046] The elevation of the upper surface of the approach slab is greater than the elevation of the upper surface of the ground beam;
[0047] The approach slab has a downward-extending concrete cushion layer at the bottom of the end near the old roadbed and pavement, and a stepped structure at the top of the end near the old roadbed and pavement.
[0048] The approach slab and the concrete pad are flush with the side facing the ground beam, and there is a gap of 100 mm ± 5% between them and the side facing the ground beam.
[0049] The stepped structure of the slab includes a recessed plane;
[0050] The concave plane is provided with a steel cover plate that can extend and retract synchronously with the approach plate in the direction of the bridge.
[0051] One end of the steel cover plate is fixed to the recessed plane or side of the ramp, and the other end crosses the gap and is in close contact with the upper surface of the ground beam, effectively isolating it from the upper surface of the ground beam and covering the opening above the gap.
[0052] Asphalt mixture is provided on the concave plane, the steel cover plate, and the ground beam within their full thickness range, and multiple layers of steel-plastic geogrid are laid in layers.
[0053] Preferably, the gap is filled with a rubber elastic foam material.
[0054] Preferably, a rubber elastic transition plate of the same thickness is installed on the upper surface of the ground beam, close to the side of the sliding end of the steel cover plate;
[0055] The rubber elastic transition plate is firmly and reliably positioned on the upper surface of the ground beam and is in close contact with the side of the sliding end of the steel cover plate.
[0056] Preferably, the stepped structure includes two recessed planes at different elevations, and the recessed plane closer to the ground beam has a lower elevation, and the recessed plane with the lowest elevation is flush with the upper surface of the ground beam;
[0057] The steel cover plate is provided on the concave plane flush with the upper surface of the ground beam and on the upper surface of the ground beam;
[0058] The steel cover plate and the stepped structure of the step plate are fixed at one end with a bent shape that matches the two concave planes of the stepped structure.
[0059] More preferably, the lower surface of the steel cover plate is in close contact with the recessed plane that is flush with the upper surface of the ground beam and the upper surface of the ground beam, effectively isolating the contact surfaces of the two to ensure that the steel cover plate can slide synchronously with the ramp.
[0060] The bent shape is reliably fixed to the stepped structure of the slab by multiple concrete-specific self-tapping reinforced anchors.
[0061] This invention also provides a construction method for the rapid and seamless reconstruction of the approach slab tail structure of the aforementioned existing bridge, comprising the following steps:
[0062] Step 1: Demolish the old roadbed and pavement within the area requiring reconstruction at the road-bridge junction; the vertical surface formed after demolishing the old roadbed and pavement must be vertical and smooth, and an adhesive must be applied.
[0063] Step 2: Construct the ground beam and form the gap between it and the approach slab near the end of the old roadbed pavement and the side of the concrete subbase below it;
[0064] Step 3: Install the steel cover plate, with one end reliably fixed to the stepped structure of the slab, and the other end spanning the gap and closely abutting the upper surface of the ground beam, while effectively isolating it from the upper surface of the ground beam;
[0065] Step 4: Lay the asphalt mixture and multiple layers of steel-plastic geogrid in layers over the full thickness of the concave plane, the steel cover plate and the ground beam, and reliably fix each layer of steel-plastic geogrid to the pre-embedded steel bars in the approach plate at the end near the approach plate.
[0066] Step 5: Finally, the asphalt pavement surface layer is laid in layers, and a certain overlap range is set between it and the old roadbed and pavement along the driving direction.
[0067] Preferably, in step 2, if there is an existing sleeper beam that can also serve as a ground beam under the approach slab of an existing bridge near the end of the old roadbed, the existing sleeper beam is broken up in the gap range corresponding to the end of the approach slab to form the ground beam.
[0068] Preferably, in step 2, if the existing bridge does not have the approach slab, the approach slab, the stepped structure, and the ground beam are cast in place.
[0069] Preferably, after the construction of the ground beam is completed, the gap is filled with rubber elastic foam material;
[0070] After the steel cover plate is installed, a rubber elastic transition plate of the same thickness is installed on the upper surface of the ground beam, close to the side of the sliding end of the steel cover plate.
[0071] The rubber elastic transition plate is firmly and reliably positioned on the upper surface of the ground beam and is in close contact with the side of the sliding end of the steel cover plate.
[0072] Preferably, in step 3, the concrete of the approach slab at heights of 210 mm ± 10% and 110 mm ± 10% is broken sequentially from the outside to the inside within a range of 150 mm along the bridge direction on the upper surface of the approach slab near the old roadbed pavement, forming two concave planes at different elevations.
[0073] Then, the steel cover plate is fixed to the stepped structure of the slab by means of multiple concrete-specific self-tapping reinforcing anchors, matching the two concave planes of the stepped structure.
[0074] Preferably, in step 5, a certain overlap range is set between the newly replaced asphalt pavement surface layer and the old roadbed pavement along the driving direction.
[0075] The beneficial effects of this invention are:
[0076] This invention addresses the increased temperature-cycle deformation and gaps under asphalt pavement at the junction of roads and bridges by setting a special structure at the end of the approach slab and adopting multiple strengthening and toughening measures to overcome the shortcomings of existing technologies.
[0077] Because the time it takes for reflective cracks to occur is directly proportional to the thickness of the asphalt pavement above it, this invention involves cutting one or more L-shaped stepped structures at the end of the slab for transition. By lowering the elevation of the top surface of the expansion joint and using full-thickness asphalt mixture for the newly replaced subgrade pavement, the thickness of the asphalt subgrade pavement is increased. Multiple layers of steel-plastic geogrid are then laid, similar to the joint reinforcement treatment used in cement pavement "white-to-black" conversions, acting like anti-crack tape. Simultaneously, a flexible rubber transition plate of the same thickness is installed at the sliding end of the expandable steel plate to reduce the displacement transmitted to the subgrade material. Through these multiple strengthening and toughening measures, the time it takes for reflective cracks to occur is delayed.
[0078] Meanwhile, a steel plate is placed over the expansion joint, with one end fixed to the approach plate and the other end sliding, thus satisfying both the flexibility requirements of the cyclic expansion joint and the rigidity requirements of the roadbed. To prevent rainwater from entering the joint and forming flowing water under vehicle loads, which could damage the roadbed and pavement, the joint is filled with elastic foam material.
[0079] The application of this invention, while ensuring that the performance and durability of the seamless asphalt pavement are no less than those of the adjacent roads, allows for flexible and rational use of existing structures, reduces investment scale, accelerates the seamless reconstruction of bridges during their service life, reduces project costs and the construction cycle for the conversion between old and new systems, and minimizes the impact on the environment and existing traffic.
[0080] The following will further explain the concept, specific structure, and technical effects of the present invention in conjunction with the accompanying drawings, so as to fully understand the purpose, features, and effects of the present invention. Attached Figure Description
[0081] Figure 1 A longitudinal cross-sectional structural schematic diagram of an embodiment of the present invention is shown.
[0082] Figure 2 A schematic diagram of the steel cover plate in one embodiment of the present invention is shown.
[0083] Figure 3 The diagram shows a longitudinal cross-sectional view of a stepped structure comprising two concave planes at different elevations in one embodiment of the present invention. Detailed Implementation
[0084] Example: Figure 1 and Figure 2 As shown, a specific embodiment of the approach slab tail structure for the rapid and seamless reconstruction of existing bridges according to the present invention includes an approach slab 1 set at the road-bridge junction, and a ground beam 2 located between the approach slab 1 and the old roadbed pavement 14 (in some embodiments, the ground beam 2 may also be a sleeper beam).
[0085] The elevation of the upper surface of the approach slab 1 is greater than the elevation of the upper surface of the ground beam 2;
[0086] The bottom of the approach slab 1 near the old roadbed pavement 14 is provided with a downward extending concrete cushion layer 3 (in some embodiments, the concrete cushion layer 3 can also be a sleeper beam), and the top of the approach slab 1 near the old roadbed pavement 14 is a stepped structure.
[0087] The sides of the approach slab 1 and the concrete pad 3 facing the ground beam 2 are flush, and there is a gap of 100 mm ± 5% between them and the sides of the ground beam 2 facing the approach slab 1 and the concrete pad 3.
[0088] The stepped structure of the slab 1 includes a recessed plane 4;
[0089] The concave plane 4 is provided with a steel cover plate 5 that can extend and retract synchronously with the approach plate 1 in the direction of the bridge;
[0090] One end of the steel cover plate 5 is fixed to the recessed plane 4 or the side of the slab 1, and the other end crosses the gap and is close to the upper surface of the ground beam 2, effectively isolating it from the upper surface of the ground beam 2 and covering the opening above the gap.
[0091] Asphalt mixture 11 is provided on the entire thickness of the concave plane 4, steel cover plate 5 and ground beam 2, and multi-layer steel-plastic geogrid 6 is laid in layers.
[0092] This invention addresses the increased temperature-cycle deformation and gaps under the asphalt pavement at the road-bridge junction by implementing a special structure at the end of the approach slab and adopting multiple reinforcement and toughening measures to overcome the shortcomings of existing technologies, as detailed below:
[0093] By forming a gap of 100 mm ± 5% between the approach slab 1 and the concrete subbase 3 near the end of the old roadbed pavement 14 and the side of the ground beam 2 facing the approach slab 1, and using the gap as an expansion joint of the approach slab 1, and covering the expansion joint with a retractable steel cover plate 5 to prevent reflective cracks from occurring on the newly replaced roadbed pavement above the gap under vehicle load.
[0094] In practical applications, multiple layers of steel-plastic geogrid 6 are laid in the asphalt mixture, and the end of each layer of steel-plastic geogrid 6 near the approach slab 1 is reliably fixed to the fixed steel bars pre-embedded in the approach slab 1. This can strengthen and toughen the asphalt mixture of the roadbed and delay the occurrence of reflective cracks.
[0095] In some embodiments, the gap is filled with a rubber elastic foam material 7.
[0096] In practical applications, to prevent rainwater from entering the gaps and forming flowing water under vehicle load, the gaps must be filled with this type of rubber elastic foam material 7.
[0097] In some embodiments, a rubber elastic transition plate 8 of the same thickness is installed on the upper surface of the ground beam 2, close to the side of the sliding end of the steel cover plate 5;
[0098] The rubber elastic transition plate 8 is firmly and reliably positioned on the upper surface of the ground beam 2 and is closely attached to the side of the sliding end of the steel cover plate 5.
[0099] Installing a rubber elastic transition plate 8 of the same thickness on the side of the sliding end that is in close contact with the steel cover plate 5 can reduce the amount of displacement transmitted to the subgrade material.
[0100] like Figure 2 and Figure 3 As shown, in some embodiments, the stepped structure includes two recessed planes 4 at different elevations, and the lower the elevation of the recessed plane 4 which is closer to the ground beam 2, the lower the elevation of the recessed plane 4, and the lowest elevation recessed plane 4 is flush with the upper surface of the ground beam 2.
[0101] A recessed plane 4 flush with the upper surface of the ground beam 2 and a steel cover plate 5 are provided on the upper surface of the ground beam 2;
[0102] The steel cover plate 5 and the stepped structure of the lap plate 1 are fixed at one end with a bent shape 9 that matches the two concave planes 4 of the stepped structure.
[0103] In some embodiments, the underside of the steel cover plate 5 is in close contact with the recessed plane 4 flush with the upper surface of the ground beam 2 and the upper surface of the ground beam 2, effectively isolating the contact surfaces of the two to ensure that the steel cover plate 5 can slide synchronously with the ramp 1.
[0104] The bent shape 9 is reliably fixed to the stepped structure of the slab 1 by multiple concrete-specific self-tapping reinforced anchors 10.
[0105] This invention also provides a construction method for the rapid and seamless reconstruction of the approach slab tail structure of existing bridges, comprising the following steps:
[0106] Step 1: Remove the old roadbed and pavement 14 within the area to be reconstructed at the road-bridge junction; the vertical surface formed after the old roadbed and pavement 14 is removed must be vertical and smooth, and an adhesive must be applied.
[0107] The broken surface of the old roadbed and pavement 14 is vertical and smooth, and an adhesive is applied to delay the time when thermal shrinkage cracks appear at the construction joint.
[0108] Step 2: Construct ground beam 2, and form a gap between it and the side of the approach slab 1 and the concrete pad 3 below it, which are close to the old roadbed pavement 14.
[0109] Step 3: Install steel cover plate 5, one end of which is reliably fixed to the stepped structure of the slab 1, and the other end spans the gap and is close to the upper surface of the ground beam 2, and is effectively isolated from the upper surface of the ground beam 2.
[0110] Step 4: Lay asphalt mixture 11 and multiple layers of steel-plastic geogrid 6 in layers over the full thickness range of the concave plane 4, steel cover plate 5 and ground beam 2, and reliably fix each layer of steel-plastic geogrid 6 to the pre-embedded fixed steel bars in the approach plate 1 at the end near the approach plate 1.
[0111] Step 5: Finally, lay the asphalt pavement surface layer 12 in layers.
[0112] In some embodiments, the feature is that, in step 2, for the case where an existing bridge approach slab 1 is provided with an existing sleeper beam that can also serve as a ground beam at the end of the old roadbed pavement 14, the existing sleeper beam is broken up by means of a joint treatment within the gap range at the tail of the corresponding approach slab 1 to form a ground beam 2.
[0113] In some embodiments, in step 2, for existing bridges without approach slabs 1, the approach slabs 1, the stepped structure, and the ground beams 2 are cast in place.
[0114] In some embodiments, after the construction of the ground beam 2 is completed, the gap is filled with rubber elastic foam material 7;
[0115] After the steel cover plate 5 is installed, a rubber elastic transition plate 8 of the same thickness is installed on the upper surface of the ground beam 2, close to the side of the sliding end of the steel cover plate 5.
[0116] The rubber elastic transition plate 8 is firmly and reliably positioned on the upper surface of the ground beam 2 and is closely attached to the side of the sliding end of the steel cover plate 5.
[0117] In some embodiments, in step 3, the concrete of the approach slab 1 at heights of 210 mm ± 10% and 110 mm ± 10% is broken sequentially from the outside to the inside within a range of 150 mm along the bridge direction on the upper surface of the approach slab 1 near the old roadbed pavement 14, forming two concave planes 4 at different elevations.
[0118] Then, the steel cover plate 5 and the two concave planes 4 of the stepped structure of the slab 1 are matched with the bending shape 9 by multiple concrete-specific self-tapping reinforcing anchors 10 to fix the stepped structure of the slab 1.
[0119] In some embodiments, in step 5, a 20cm overlap is provided between the newly replaced asphalt pavement 12 and the old roadbed 14 along the direction of travel.
[0120] The aforementioned technical means actually involves staggering the structural joints and thermal shrinkage joints at the interface between the newly added asphalt mixture 11 and the old roadbed pavement 14.
[0121] The preferred embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.
Claims
1. A slab tail structure for rapid and seamless reconstruction of existing bridges, comprising a slab (1) set at the road-bridge junction, and a ground beam (2) located between the slab (1) and the old roadbed pavement (14); characterized in that: The elevation of the upper surface of the approach slab (1) is greater than the elevation of the upper surface of the ground beam (2); The approach slab (1) has a downwardly extending concrete cushion layer (3) at the bottom of the end near the old roadbed pavement (14), and a stepped structure at the top of the end near the old roadbed pavement (14). The approach slab (1) and the concrete pad (3) are flush with the side of the ground beam (2), and there is a gap of 100 mm ± 5% between them and the side of the ground beam (2) facing the approach slab (1) and the concrete pad (3). The stepped structure of the slab (1) includes a recessed plane (4). The concave plane (4) is provided with a steel cover plate (5) that can extend and retract synchronously with the approach plate (1) in the direction of the bridge. One end of the steel cover plate (5) is fixed to the recessed plane (4) or side of the ramp (1), and the other end crosses the gap and is close to the upper surface of the ground beam (2), and is effectively isolated from the upper surface of the ground beam (2), thus covering the opening above the gap. Asphalt mixture (11) is provided on the entire thickness of the concave plane (4), the steel cover plate (5) and the ground beam (2), and multiple layers of steel-plastic geogrid (6) are laid in layers. On the upper surface of the ground beam (2), a rubber elastic transition plate (8) of the same thickness is installed on the side of the sliding end of the steel cover plate (5). The rubber elastic transition plate (8) is firmly and reliably positioned on the upper surface of the ground beam (2) and closely attached to the side of the sliding end of the steel cover plate (5).
2. The approach slab tail structure for rapid and seamless reconstruction of existing bridges according to claim 1, characterized in that, The gap is filled with rubber elastic foam material (7).
3. The approach slab tail structure for rapid and seamless reconstruction of existing bridges according to claim 1, characterized in that, The stepped structure includes two recessed planes (4) at different elevations, and the recessed plane (4) closer to the ground beam (2) has a lower elevation, and the recessed plane (4) with the lowest elevation is flush with the upper surface of the ground beam (2). The concave plane (4) flush with the upper surface of the ground beam (2) and the upper surface of the ground beam (2) are provided with the steel cover plate (5). The steel cover plate (5) and the stepped structure of the step plate (1) are fixed at one end with a bent shape (9) that matches the two concave planes (4) of the stepped structure.
4. The approach slab tail structure for rapid and seamless reconstruction of existing bridges according to claim 3, characterized in that, The lower surface of the steel cover plate (5) is closely attached to the recessed plane (4) which is flush with the upper surface of the ground beam (2) and the upper surface of the ground beam (2), effectively isolating the contact surfaces of the two to ensure that the steel cover plate (5) can slide synchronously with the ramp (1). The bent shape (9) is reliably fixed to the stepped structure of the slab (1) by a plurality of concrete-specific self-tapping reinforced anchors (10).
5. The reconstruction construction method for the approach slab tail structure of an existing bridge for rapid and seamless reconstruction according to claim 1, characterized in that, Includes the following steps: Step 1: Demolish the old roadbed and pavement (14) within the area to be reconstructed at the road-bridge junction; the vertical surface formed after the old roadbed and pavement (14) is demolished must be vertical and smooth, and an adhesive must be applied. Step 2: Construct the ground beam (2) and form the gap between the approach slab (1) near the end of the old roadbed pavement (14) and the side of the concrete cushion layer (3) below it; Step 3: Install the steel cover plate (5), one end of which is reliably fixedly connected to the stepped structure of the step plate (1), and the other end crosses the gap and is close to the upper surface of the ground beam (2), and is effectively isolated from the upper surface of the ground beam (2); Step 4: Lay the asphalt mixture (11) and multiple layers of steel-plastic geogrid (6) in layers on the full thickness of the concave plane (4), the steel cover plate (5) and the ground beam (2), and reliably fix each layer of steel-plastic geogrid (6) to the pre-embedded fixed steel bars in the slab (1) at the end of the slab (1). Step 5: Finally, lay the asphalt pavement layer (12) in layers and set a certain overlap range between it and the old roadbed pavement (14) along the driving direction.
6. The reconstruction construction method for the approach slab tail structure of an existing bridge for rapid and seamless reconstruction according to claim 5, characterized in that, In step 2, if there is an existing sleeper beam that can also serve as a ground beam under the end of the approach plate (1) of the existing bridge near the old roadbed pavement (14), the existing sleeper beam is broken up by means of joint treatment within the gap range corresponding to the end of the approach plate (1) to form the ground beam (2).
7. The reconstruction construction method for the approach slab tail structure of an existing bridge for rapid and seamless reconstruction according to claim 5, characterized in that, In step 2, if the existing bridge does not have the approach slab (1), then the approach slab (1), the stepped structure, and the ground beam (2) are cast in place.
8. The reconstruction construction method for the approach slab tail structure of an existing bridge for rapid and seamless reconstruction according to claim 5, characterized in that, After the construction of the ground beam (2) is completed, rubber elastic foam material (7) is filled into the gap. After the steel cover plate (5) is completed, a rubber elastic transition plate (8) of the same thickness is installed on the upper surface of the ground beam (2) close to the side of the sliding end of the steel cover plate (5). The rubber elastic transition plate (8) is firmly and reliably positioned on the upper surface of the ground beam (2) and closely attached to the side of the sliding end of the steel cover plate (5).
9. The reconstruction construction method for the approach slab tail structure of an existing bridge for rapid and seamless reconstruction according to claim 5, characterized in that, In step 3, the concrete of the approach plate (1) at a height of 210 mm ± 10% and 110 mm ± 10% is broken from the outside to the inside within a range of 150 mm along the bridge direction on the upper surface of the approach plate (1) near the old roadbed pavement (14), forming two concave planes (4) at different elevations. Then, the steel cover plate (5) is fixed to the stepped structure of the step plate (1) by means of a plurality of concrete-specific self-tapping reinforcing anchors (10) with the two concave planes (4) of the stepped structure of the step plate (1) in a bent shape (9).
10. The reconstruction construction method for the approach slab tail structure of an existing bridge for rapid and seamless reconstruction according to claim 5, characterized in that, In step 5, a 20cm overlap is provided between the newly replaced asphalt pavement (12) and the old roadbed (14) along the driving direction.