Symmetrical gradually-changing span continuous v-shaped arch bridge

Abstract

The application discloses a symmetrically gradually-changing span continuous V-shaped arch bridge and relates to the related technical field of bridge construction. The bridge main body arrangement system adopts a multi-span symmetrically gradually-changing span arrangement, is a multi-connection segmented structure as a whole, adopts left-right split cross section arrangement, is provided with people-vehicle separated lanes, middle separation and bidirectional drainage cross slopes; the upper main body structure is a V-shaped rigid frame and arch rib combined prestressed concrete box girder structure, the span gradually increases from the side span to the middle span in a symmetric manner, and the gradually-changing beam height is correspondingly arranged; the box girder adopts a single-box three-chamber section; the arch rib adopts a single-box single-chamber double-arch rib arrangement; the local hanging beam adopts a simply-supported structure, one end of which is connected with the box girder through a telescopic structure, and the other end is connected with the box girder through a continuous bridge deck structure; the lower supporting structure comprises solid bridge piers, gravity abutments and bored pile foundations, and the piers, the abutments and the pile foundations are matched with section sizes and pile diameter specifications according to structural stress gradients.

Description

Technical Field

[0001] This invention relates to the technical field of bridge construction, specifically to a symmetrical, gradually changing span continuous V-shaped arch bridge. Background Technology

[0002] As is generally known, in the construction of highway and municipal bridges, large-span prestressed concrete rigid frame arch composite bridges are typically used, taking into account the construction conditions of coastal mudflats, soft soil foundations, large-span layouts, and salt spray corrosion environments. These bridges must meet the requirements of heavy-load highway traffic, large spans, overall stability, and long-term durability. Conventional designs often employ multi-span continuous layouts, segmented cross-sections, prestressed concrete superstructures, solid piers and drilled pile foundations, and are equipped with supporting structures such as bridge deck paving, drainage systems, expansion joints, pot bearings, crash barriers, and pedestrian railings, forming a complete bridge structural system.

[0003] In existing technologies, similar bridges generally suffer from insufficient adaptation of substructure corrosion protection and durability in their design: key components such as bridge piles, abutments, piers, and arches are subjected to Class III environments with chloride ion corrosion for extended periods; ordinary concrete has low resistance to seepage and chloride ion diffusion; the thickness of the steel reinforcement protective layer is too small and not differentiated according to environmental zones; and underwater pile foundations lack targeted anti-corrosion structures. At the same time, important load-bearing components do not have their durability indicators controlled according to the 100-year design reference period, making later maintenance and replacement difficult and prone to defects such as concrete deterioration, steel corrosion, and structural cracking, which makes it difficult to meet the requirements for long-term safe service of bridges in coastal environments.

[0004] To address the aforementioned shortcomings, this invention provides a V-shaped rigid frame arch bridge design scheme adapted to coastal corrosive environments, thereby meeting the requirements of engineering construction and long-term use. Summary of the Invention

[0005] The purpose of this invention is to provide a symmetrical, gradually changing span continuous V-shaped arch bridge, solving the technical problems in related technologies. To achieve the above objective, this invention provides the following technical solution: A symmetrical, gradually varying span continuous V-shaped arch bridge includes: The main bridge layout system adopts a multi-span symmetrical gradually changing span arrangement. The overall structure is a multi-segmented segmented structure, with left and right cross-sections, and features pedestrian and vehicle separation, central isolation, and bidirectional drainage cross slopes. The superstructure is a prestressed concrete box girder structure combining a V-shaped rigid frame and arch ribs. The span gradually increases symmetrically from the side span to the middle span, with corresponding gradual beam heights. The box girder adopts a single-box three-cell section. The arch ribs adopt a single-box single-cell double-arch rib arrangement. The local hanging beams adopt a simply supported structure, with one end equipped with an expansion joint to connect with the box girder, and the other end connected to the box girder using a continuous bridge deck structure. The substructure includes solid piers, gravity abutments, and bored pile foundations. The piers, abutments, and pile foundations are matched with the cross-sectional dimensions and pile diameter specifications according to the structural stress gradient. The bridge deck ancillary system includes composite bridge deck paving, drainage system, crash barriers and pedestrian railings; The seismic fortification system is designed according to the seismic fortification standard for highway bridges, matching the corresponding seismic intensity and site category, and is equipped with shock-absorbing pot bearings, seismic blocks on the pier tops and buffer rubber pads between beams. The key sections of the pier body and pile foundation adopt a stirrup-reinforced ductile structure. The corrosion-resistant and durable protection system is designed according to the coastal corrosion environment. The main components are made of graded corrosion-resistant concrete, and the concrete hydration index, chloride ion diffusion coefficient and steel reinforcement protective layer thickness are strictly controlled. Exposed components are divided into atmospheric zone and splash zone with differentiated heavy-duty anti-corrosion coating. The underwater pile foundation is equipped with permanent anti-corrosion steel casing and a special anti-corrosion coating process.

[0006] The aforementioned bridge main structure features a symmetrically varying span arrangement from the side spans to the middle span, with span specifications of 50 meters, 60 meters, and 80 meters arranged symmetrically. The bridge is constructed in multiple sections to release temperature deformation and shrinkage creep stress. The cross-sections are divided into carriageways, sidewalks, guardrails, and a central median. The carriageways have a 1.5% cross slope, and the sidewalks have a 2.0% cross slope.

[0007] The aforementioned upper main structure, except for the V-shaped rigid frame area which uses ordinary reinforced concrete, uses prestressed concrete Class A components; the prestressing system uses high-strength low-relaxation steel strands and a group anchorage system; the prestressing ducts use corrugated metal pipes for drilling and vacuum-assisted grouting; the 50-meter, 60-meter, and 80-meter spans are respectively configured with gradually varying arch top beam heights, and the wall thickness of the box girder and arch rib sections is configured differently according to the stress conditions.

[0008] As mentioned above, the lower supporting structure, such as the abutment and pile foundation, adopts different planar dimensions, abutment thickness, and bored pile diameter according to the main beam span and vertical load gradient. The abutment adopts a gravity structure, which is suitable for the bearing capacity and earth pressure resistance requirements of soft soil and coastal sites.

[0009] The bridge deck ancillary system described above uses a composite structure of asphalt concrete and cement concrete for the bridge deck pavement; the bridge deck drainage adopts a combination of longitudinal and transverse drainage, and the collected water is led to the rainwater collection well of the pier through vertical drainage pipes and longitudinal collection pipes; the guardrails and railings are made of steel components and are coated with an overall anti-rust and anti-corrosion coating.

[0010] The aforementioned seismic fortification system site is a Class II site, configured according to a seismic fortification intensity of 7 degrees and a seismic measure level of 8 degrees; the plastic hinge zone at the top and bottom of the bridge piers and the limited area at the top of the pile foundation are reinforced with stirrups; a seismic isolation distance is reserved between the bridge end and the top of the bridge pier; and buffer rubber pads are installed between the bridge bodies and between the bridge end and the back wall.

[0011] The aforementioned anti-corrosion and durability protection system is designed differently for Class II corrosion environments in the upper part and Class III corrosion environments in the lower part; the box girder, pier, arch seat, pile cap, and pile foundation are respectively matched with corrosion-resistant concrete of corresponding strength grade, and the maximum water-cement ratio, alkali content and chloride ion content are strictly controlled, and the minimum protective layer thickness of the steel reinforcement of each component and the 28d chloride ion diffusion coefficient are limited; the atmospheric zone and the splash zone respectively adopt a matching multi-layer heavy anti-corrosion coating system, and the steel casing of the underwater pile foundation is sandblasted and rusted, and then coated with epoxy zinc-rich primer and epoxy coal tar topcoat to form a composite anti-corrosion protective layer.

[0012] The aforementioned expansion joint between the hanging beam and the box girder adopts a D160 type expansion joint.

[0013] The aforementioned telescopic structure includes a central beam and two side beams symmetrically arranged on both sides of the central beam. Each side beam has several displacement control systems arranged sequentially along its length. The central beam has several crossbeams arranged sequentially along its length, with each end of a crossbeam corresponding to one of the two displacement control systems. Several anchoring structures are arranged on the side beams. Both the side beams and the central beam have slots, and limiting components are provided in the slots. A waterstop is arranged between the side beams and the central beam, and the locking feet of the waterstop are connected to the limiting components. Based on the limiting effect of the limiting components, the locking feet on one side of the waterstop are movably restricted to the side beam, and the locking feet on the other side are movably restricted to the central beam.

[0014] The aforementioned limiting component includes a card seat that is slidably arranged in a slot along the extension and retraction direction of the bridge body. The card seat is locked in the slot by a locking mechanism. An eccentrically rotating pressure roller is arranged in the card seat. The clamping foot of the waterstop is installed on the pressure roller, and the position of the clamping foot is at the position furthest from the center of rotation of the pressure roller. During the stretching stroke of the waterstop, the pressure roller gradually rotates to press the waterstop. When the position of the clamping foot is directly below the center of rotation of the pressure roller, the locking mechanism releases the position lock of the card seat based on the squeezing action of the waterstop.

[0015] The beneficial effects of this invention are as follows: by optimizing the bridge structural system, classifying concrete materials, controlling durability parameters, applying zoned anti-corrosion coatings, and constructing permanent protective structures for underwater pile foundations, the invention achieves a balance between bridge structural safety, seismic reliability, and long-term corrosion protection, thereby meeting the requirements of engineering construction and long-term use. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this invention. For those skilled in the art, other drawings can be obtained based on these drawings.

[0017] Figure 1 This is a schematic diagram of the planar structure of a symmetrical, gradually changing span continuous V-shaped arch bridge provided in an embodiment of the present invention; Figure 2 This is a three-dimensional structural diagram of a telescoping structure for a symmetrical, gradually changing span continuous V-shaped arch bridge provided in an embodiment of the present invention. Figure 3 This is a three-dimensional structural diagram of the telescopic structure of a symmetrical, gradually changing span continuous V-shaped arch bridge provided in an embodiment of the present invention. Figure 4 for Figure 3 A schematic diagram of the cross-sectional structure at point AA; Figure 5 for Figure 3 A first-person perspective diagram of the exploded structure; Figure 6 for Figure 3 A second-view diagram of the explosion structure.

[0018] Explanation of reference numerals in the attached figures: 1. Bridge; 10. Box girder; 11. Arch rib; 12. Hanging beam; 13. Pier; 14. Abutment; 15. Pile foundation; 2. Expansion joint; 20. Middle beam; 21. Side beam; 22. Crossbeam; 23. Anchorage structure; 24. Slot; 25. Waterstop; 26. Seat; 27. Pressure roller; 28. Displacement control box; 29. ​​Connecting seat; 30. Rubber bearing; 31. Locking rod; 32. Locking groove; 33. Transmission rod; 34. Pressure block; 35. Covering strip; 36. Slot. Detailed Implementation

[0019] To enable those skilled in the art to better understand the technical solution of the present invention, the following will be described in conjunction with the appendix. Figure 1 To be continued Figure 6 The present invention will now be described in further detail.

[0020] In one embodiment of the present invention, a symmetrical, gradually changing span continuous V-shaped arch bridge is provided, comprising: The main structure of Bridge 1 adopts a multi-span symmetrical gradually changing span arrangement. The overall structure is a multi-segmented segmented structure, with left and right cross-sections, and features separation of pedestrian and vehicular traffic, central isolation, and bidirectional drainage cross slopes. The superstructure is a prestressed concrete box girder 10 structure composed of a V-shaped rigid frame and arch ribs 11. The span gradually increases symmetrically from the side span to the middle span, and the beam height is configured accordingly. The box girder 10 adopts a single box three-cell section. The arch ribs 11 adopt a single box single-cell double arch rib arrangement. The partial hanging beam 12 adopts a simply supported structure. One end of the beam is equipped with an expansion joint 2 to connect with the box girder 10, and the other end is connected to the box girder 10 by a bridge deck continuous structure. The substructure includes solid piers 13, gravity abutments 14, and bored pile foundations 15. The piers 13, abutments 14, and pile foundations 15 are matched with their cross-sectional dimensions and pile diameter specifications according to the structural stress gradient. The bridge deck ancillary system includes composite bridge deck paving, drainage system, crash barriers and pedestrian railings; The seismic fortification system is designed according to the seismic fortification standard for highway bridges, matching the corresponding seismic intensity and site category, and is equipped with shock-absorbing pot bearings, seismic blocks on the pier tops and buffer rubber pads between beams. The pier body and the 15 key sections of the pile foundation adopt a stirrup-reinforced ductile structure. The corrosion-resistant and durable protection system is designed according to the coastal corrosion environment. The main components are made of graded corrosion-resistant concrete, and the concrete hydration index, chloride ion diffusion coefficient and steel reinforcement protective layer thickness are strictly controlled. Exposed components are divided into atmospheric zone and splash zone with differentiated heavy-duty anti-corrosion coating. The underwater pile foundation 15 is equipped with permanent anti-corrosion steel casing and a special anti-corrosion coating process.

[0021] The main structure of Bridge 1 is arranged with the spans gradually changing symmetrically from the side spans to the middle span. The span specifications are arranged symmetrically in the order of 50 meters, 60 meters and 80 meters. Bridge 1 is set up in multiple sections to release temperature deformation and shrinkage creep stress. The cross section is set with a carriageway, a sidewalk, guardrails and a central divider. The carriageway is set with a cross slope of 1.5% and the sidewalk is set with a cross slope of 2.0%.

[0022] Specifically, the symmetrical, gradually increasing-span continuous V-shaped arch bridge adopts a 9-span V-shaped rigid frame continuous arch bridge structure. Each span is arranged symmetrically from left to right, gradually increasing in size from the side spans to the middle span. The specific span arrangement is: 50m+50m+60m+60m+80m+60m+60m+50m+50m, with a total bridge length of 535m. The entire bridge is divided into 9 sections longitudinally, with lengths of 87m, 118m, 140m, 88m, and 87m respectively. This multi-segmented construction effectively releases the stress from temperature deformation of the beams and shrinkage and creep of the concrete, while also accommodating uneven site settlement and the requirements of segmented cast-in-place construction. Bridge 1 adopts a dual-span, independently designed structure, with a standard width of 18.75m for each span and a 1m central median strip between the two spans. The total standard cross-sectional width of Bridge 1 is 38.5m, consisting of a 3.25m pedestrian walkway, a 15m roadway, a 0.5m guardrail, a 1m median strip, another 0.5m guardrail, a 15m roadway, and a 3.25m pedestrian walkway, achieving separation of pedestrians and vehicles, and isolation of motorized and non-motorized traffic. The bridge deck is equipped with a two-way drainage cross slope, with a 1.5% cross slope for the roadway and a 2.0% cross slope for the pedestrian walkway. This cross slope is used to quickly drain rainwater from the bridge deck, reducing the erosion of concrete and prestressed structures caused by water accumulation.

[0023] Except for the V-shaped rigid frame area which uses ordinary reinforced concrete, the rest of the upper main structure uses prestressed concrete Class A components; the prestressing system uses high-strength low-relaxation steel strands and a group anchoring system, and the prestressing ducts use corrugated metal pipes for drilling and vacuum-assisted grouting process; the 50-meter, 60-meter, and 80-meter spans are respectively configured with gradually changing arch top beam heights, and the wall thickness of the box girder 10 and arch rib 11 sections is configured differently according to the stress conditions.

[0024] Specifically, the superstructure adopts a combined load-bearing system of V-shaped rigid frames and arch ribs 11. Except for the local areas of the V-shaped rigid frames which use ordinary reinforced concrete structures, the remaining main beams and arch ribs 11 are all prestressed concrete structures. The main beams are designed and controlled as prestressed concrete Class A components, effectively limiting the development of structural cracks. The clear span-to-span ratios of each span of the entire bridge are adapted to the load and alignment in the following order: 1 / 7.8, 1 / 6.6, 1 / 6.4, 1 / 5.4, and 1 / 7.1. The span and beam height are gradually matched: the arch crown beam height is 2.0m for the 50m span, 2.5m for the 60m span, and 3.0m for the 80m span, achieving optimal matching of stiffness and self-weight under large spans. The top slab of the arched box girder 10 has a width of 18.75m, a single-sided cantilever length of 2.5m, and a bottom slab width of 13.75m. Box girder 10 adopts a single-box, three-cell cross-section. At mid-span, the top slab thickness is 25cm, the bottom slab thickness is 25cm, and the web thickness is 50cm. Each span of the bridge features a double-arch rib arrangement 11, with each arch rib 11 being 5m wide and the net distance between them being 3.75m. Arch rib 11 adopts a single-box, single-cell cross-section, with its height equal to that of the arched box girder 10 in the same span. At mid-span, the top and bottom slab thicknesses of arch rib 11 are both 28cm, and the web thickness is 60cm. Suspended beams 12 are installed in spans 2, 4, 6, and 8. Suspended beams 12 employ a simply supported structural system, with one end featuring an expansion joint and the other end using a continuous bridge deck structure, balancing beam deformation release and driving smoothness. The prestressing system adopts high-strength, low-relaxation steel strands conforming to the national standard GB / T5224-2003; the design anchor tension control stresses are 1395MPa and 1302MPa respectively. Longitudinal prestressing tendons utilize a large-tonnage group anchor system, and prestressing ducts are formed using pre-embedded corrugated metal pipes. After prestressing tensioning, vacuum-assisted grouting is employed to ensure duct compaction and prevent steel strand corrosion. The construction of box girder 10 employs full-span scaffolding or steel pipe scaffolding for in-situ casting, with each section cast in one continuous pour. The entire bridge is divided into eight construction segments. After the scaffolding is erected, a preload of no less than 1.2 times the construction load is applied to eliminate inelastic deformation and accurately reserve elevation and settlement allowance. Prestressing tensioning can only be carried out after the concrete strength and elastic modulus reach 90% of the design strength. Tensioning follows the principle of "longitudinal tendons of the web → longitudinal tendons of the bottom plate → longitudinal tendons of the top plate, tensioning the longer tendons first and then the shorter ones, and tensioning symmetrically". The tensioning stress and elongation are controlled simultaneously, with the elongation error controlled within 6%. The breakage and slippage of wires are strictly controlled according to the limits specified in the standard.

[0025] The lower supporting structure, the abutment and pile foundation 15, adopt different planar dimensions, abutment thickness and bored pile diameter according to the main beam span and vertical load gradient; the abutment 14 adopts a gravity structure, which is suitable for the bearing capacity and earth pressure resistance requirements of soft soil and coastal sites.

[0026] Specifically, the substructure consists of solid piers 13, gravity abutments 14, and bored pile foundations 15. Pier 13 adopts an integral solid pier form, with two piers 13 per bridge span. The thickness is 2m, and 3 to 4 sonic logging pipes are pre-embedded. The clear distance between piers 13 is 2.75m. Based on the differences in vertical load of each pier, the size of the pier cap, the thickness of the pier cap, and the diameter of the pile foundation 15 are designed differently according to different levels: Piers 1# and 8# have a pier cap size of 15.95m × 9m and a pier cap thickness of 2m, with the foundation using 6 bored piles with a diameter of 1.5m; Piers 2#, 3#, 6#, and 7# have a pier cap size of 15.95m × 10m and a pier cap thickness of 2.5m, with the foundation using 6 bored piles with a diameter of 1.8m; Piers 4# and 5# have a pier cap size of 15.95m × 10m and a pier cap thickness of 2.5m, with the foundation using 6 bored piles with a diameter of 2.0m. Bridge abutment 14 adopts a gravity-type abutment structure, with a foundation consisting of eight 151.5m diameter bored cast-in-place piles. These piles rely on their own weight to balance the back soil pressure, adapting to the bearing characteristics of the soft coastal soil site. All foundations are constructed using bored cast-in-place piles. Land piles 15 utilize conventional drilling techniques. The underwater piers, located in the shallow waters of a shrimp pond, were constructed using an island-building cofferdam for the abutment and pile foundations 15. Pile foundations 15 were rigorously cleaned according to end-bearing pile design requirements, with a pile bottom sediment thickness not exceeding 5cm. The entire cross-section of bridge abutment 14 was embedded at least 3m into fresh rock, and bridge pier 13 was embedded at least 4m. Each pile had 3-4 pre-embedded sonic logging tubes, and ultrasonic testing was used for each pile, with core sampling supplementing key pile locations to ensure the quality of pile foundation 15 construction. The abutment is a large-volume concrete structure. During construction, temperature control measures were implemented, including reducing heat of hydration, controlling the temperature upon placement of the formwork, strengthening curing, and strictly controlling the demolding time, to avoid structural cracks caused by temperature differences due to hydration heat and shrinkage. The pier body is formed by one-time casting of integral steel mold without tie rods, and cement from the same manufacturer is used to ensure consistent appearance and color; the pier body stirrups adopt a closed structure with 135° hooks at the ends, and the hooks of adjacent stirrups are staggered along the pier height; the exposed concrete surface is kept moist for no less than 72 hours.

[0027] The bridge deck ancillary system uses a composite structure of asphalt concrete and cement concrete for the bridge deck pavement; the bridge deck drainage adopts a combination of longitudinal and transverse drainage, and the collected water is led to the rainwater collection well of the pier through vertical drainage pipes and longitudinal collection pipes; the guardrails and railings are made of steel components and are coated with an overall anti-rust and anti-corrosion coating.

[0028] Specifically, the bridge deck pavement adopts a composite structure, consisting of a 10cm thick asphalt concrete surface layer and a 6cm thick C50 cement concrete base layer from top to bottom. The bridge's expansion joints are configured according to deformation levels: NJSF80 expansion joints are used at 14 locations on both abutments, and NJSF160 expansion joints are used at the movable ends of the suspended beams, adapting to the expansion and contraction displacement requirements of the beams at different locations. All bridge bearings uniformly adopt 15GPZ (2009) vibration-damping pot bearings (30mm), meeting the requirements for vertical loads, horizontal loads, vehicle braking forces, temperature, shrinkage, and creep deformation of the beams. The pedestrian railings and crash barriers are all made of steel, with a simple and aesthetically pleasing design that coordinates with the overall bridge structure. All steel railings and guardrails undergo rust-proof and heavy-duty anti-corrosion coating treatment. The bridge deck drainage system adopts a combination of longitudinal and transverse drainage. Utilizing the transverse slope of the bridge deck, water is collected through vertical drainage pipes on the outside of the sidewalk curb and longitudinal collection pipes, and then led to rainwater collection wells at the pier locations, achieving orderly discharge of rainwater from the bridge deck. Bridge 1 has reserved provisions for the pre-buried structures of public utility pipelines such as communication, power, and cable television to meet the passage requirements of municipal pipelines.

[0029] The site of the seismic fortification system is a Class II site, configured according to a seismic fortification intensity of 7 degrees and a seismic measure level of 8 degrees; the plastic hinge zone at the top and bottom of pier 13 and the limited area at the top of pile foundation 15 are reinforced with stirrups; a seismic isolation distance is reserved between the end of bridge 1 and the top of pier 13; and buffer rubber pads are installed between bridge 1 bodies and between the end of bridge 1 and the back wall.

[0030] Specifically, according to the "Detailed Rules for Seismic Design of Highway Bridges," this bridge is classified as a Class B bridge, with a basic seismic intensity of 7 degrees, a basic design earthquake acceleration of 0.15g, and a characteristic period of 0.40s. The site's equivalent shear wave velocity and overburden thickness classify it as a Class 15 site for pile foundation 15 (II pile foundation). As required by the specifications, the seismic fortification measures for this bridge are upgraded to the 8-degree standard. The seismic fortification objectives are: under E1 earthquake action, the structure will be basically undamaged and can be used normally without repair; under E2 earthquake action, there will be no collapse or serious structural damage, and emergency traffic can be maintained after temporary reinforcement. Reinforcement details for ductile members: Pier 13 uses 16mm diameter HRB335 steel bars for the stirrups; the stirrup spacing in the plastic hinge zone at the pier top and bottom is increased to 10cm, and the stirrup spacing in other sections is no more than 20cm; Pile foundation 15 has φ12@10cm spiral stirrups within a 10m radius of the pile top, and φ12@20cm stirrups within the rest of the pile body. Seismic structural measures: A 110cm distance is reserved between the end of the continuous beam and the edge of the pier top to meet the requirements of the seismic beam design specifications; buffer rubber pads are installed between beams, between beam ends and the back wall, and between the beam body and the seismic blocks; seismic blocks are uniformly installed on the pier tops, working in conjunction with the 15GPZ(2009) damping pot bearings of the pile foundation to dissipate seismic energy and limit beam displacement. Structural calculations were performed using "Bridge Doctor 1" V3.2 for the main analysis and reviewed using MidasCivil 2011; calculation parameters were taken based on highway Class I load, ambient relative humidity of 80%, overall temperature rise / fall of 20℃, and the standard temperature gradient effect to ensure accurate and reliable seismic and stress calculations.

[0031] The corrosion protection system is designed differently for Class II and Class III corrosion environments in the upper part. The box girder 10, pier body, arch seat, pile cap, and pile foundation 15 are matched with corrosion-resistant concrete of corresponding strength grades. The maximum water-cement ratio, alkali content and chloride ion content are strictly controlled, and the minimum protective layer thickness of the steel reinforcement of each component and the 28-day chloride ion diffusion coefficient are limited. The atmospheric zone and the splash zone adopt matching multi-layer heavy-duty anti-corrosion coating system. After sandblasting and rust removal, the steel casing of the underwater pile foundation 15 is coated with epoxy zinc-rich primer and epoxy coal tar topcoat to form a composite anti-corrosion protective layer.

[0032] Specifically, the bridge site is near a bay, and the surface water is highly mineralized saline with acidic corrosive properties. The structure is designed for durability and corrosion resistance based on Class 15 environments for the upper pile foundation (Pile 15Ⅱ) and Class 15 environments for the lower pile foundation (Pile 15Ⅲ). Key components that are difficult to replace, such as Pile 15 and Piers 13, are controlled for durability indicators based on a 100-year design reference period. The concrete strength and durability indicators of each component are graded: C50 concrete is used for the cast-in-place box girder 10, C40 concrete for the arch abutments and abutments, C35 corrosion-resistant concrete for the pier caps and Pile 15, and C30 concrete for the bridge approach slabs. Strict control is maintained over the concrete mix design: the maximum water-cement ratio for structural concrete is no greater than 0.45, and the total alkali content does not exceed 1.8 kg / m³; the maximum chloride ion content for prestressed components is 0.06%, and the minimum cement content is 360 kg / m³; the maximum chloride ion content for ordinary components is 0.10%, and the minimum cement content is 300 kg / m³. Non-alkali-reactive aggregates are preferred as raw materials. The minimum protective layer thickness and impermeability index of the reinforcing steel bars for each component are strictly limited: 8.5cm for foundation piles, 6.0cm for pile caps, and 4.5cm for arch abutments and bearing pads; the chloride ion diffusion coefficient of the concrete of all key lower components after 28 days is less than 7×10⁻⁶. -12 m² / s. The exposed steel structure and concrete surface of the entire bridge adopt a long-lasting heavy-duty anti-corrosion coating system with a design service life of 15 years: In the atmospheric zone, one coat of epoxy resin sealing paint + two coats of epoxy micaceous iron oxide intermediate paint for pile foundation 15 (total thickness 100μm) + two coats of acrylic polyurethane topcoat (total thickness 80μm); In the splash zone and water level fluctuation zone, three coats of moisture-curing epoxy micaceous iron oxide intermediate paint (total thickness 180μm) + two coats of aliphatic acrylic polyurethane topcoat (total thickness 80μm). The underwater pile foundation 15 is equipped with a permanent steel casing and professional anti-corrosion treatment: the surface of the steel casing is sandblasted to Sa2.5 grade and the surface roughness Rz30~70μm; 25μm epoxy zinc-rich primer and 300μm epoxy coal tar topcoat are sprayed in sequence; the ambient temperature during the coating construction is controlled to be no lower than 3℃ and the humidity is no higher than 85%. After sandblasting, the primer is sealed in time, and the coating is applied in layers. The thickness is checked for each layer. After curing, it is lowered and installed.

[0033] In another embodiment of the present invention, the expansion joint 2 between the hanging beam 12 and the box beam 10 adopts a D160 type expansion joint, selected according to the actual displacement to ensure normal operation. That is, the expansion joint 2 includes a middle beam 20 and two side beams 21 symmetrically arranged on both sides of the middle beam 20. Several displacement control systems are arranged sequentially along the length direction of each side beam 21. Several cross beams 22 are arranged sequentially along the length direction of the middle beam 20. The two ends of the cross beams 22 correspond to two displacement control systems respectively. Several anchoring structures 23 are arranged on the side beams 21. The side beams 21 and the middle beam 20 are both provided with slots 24. Limiting components are provided in the slots 24. A waterstop 25 is arranged between the side beams 21 and the middle beam 20. The locking feet of the waterstop 25 are connected to the limiting components. Based on the limiting effect of the limiting components, the locking feet on one side of the waterstop 25 are movably restricted on the side beam 21, and the locking feet on the other side are movably restricted on the middle beam 20.

[0034] Specifically, in the existing expansion joint 2, the clamps of the waterstop 25 are directly clamped in the grooves 24 of the steel sections (side beam 21 and middle beam 20). When the bridge 1 expands and contracts, there is hard friction and strong pulling between the clamps and the grooves 24. This will cause the grooves 24 to wear faster, and the clamps of the waterstop 25 will also be prone to fatigue cracking or even falling off due to long-term tension and shearing.

[0035] Based on the above problems, in this embodiment, the connection between the clamp foot and the clamp groove 24 is made through a limiting component. By utilizing the limiting effect of the limiting component, the connection between the clamp foot and the steel section (side beam 21 and middle beam 20) is movable. That is, the telescopic structure 2 in this embodiment is arranged between the tie beam and the box girder 10. One side beam 21 is connected to the tie beam through the anchoring structure 23, and the other side beam 21 is also connected to the box girder 10 through the anchoring structure 23. The middle beam 20 is located in the middle of the two side beams 21. Several displacement control systems are arranged sequentially along the width direction of the bridge 1 below each side beam 21 (below the bridge deck). The function is to automatically distribute the displacement of each gap when the bridge 1 undergoes expansion and contraction deformation due to temperature, load, etc., to ensure that all gap widths are uniform and change synchronously, and to avoid local stress concentration. Several cross beams 22 are arranged sequentially along the width direction of the bridge 1 below the middle beam 20. Each end of each cross beam 22 is connected to a displacement control system.

[0036] In one optional embodiment, the limiting component includes a card seat 26 slidably arranged in a card slot 24 along the telescopic direction of the main body of the bridge 1. The card seat 26 is locked in the card slot 24 by a locking mechanism. A pressure roller 27 is eccentrically arranged in the card seat 26. The clamping foot of the waterstop 25 is installed on the pressure roller 27, and the position of the clamping foot is at the position furthest from the center of rotation of the pressure roller 27. During the stretching stroke of the waterstop 25, the pressure roller 27 gradually rotates to press the waterstop 25. When the position of the clamping foot is directly below the center of rotation of the pressure roller 27, the locking mechanism releases the position lock of the card seat 26 based on the squeezing action of the waterstop 25.

[0037] Specifically, the opening size of the slot 24 is smaller than the internal cavity size, meaning that the card holder 26 can slide within the slot 24 along the expansion and contraction direction of the bridge 1, but cannot detach from the slot 24 in that direction. When installing the card holder 26 into the slot 24, it needs to be inserted from the end of the slot 24. During the normal expansion and contraction of the bridge 1, the locking mechanism locks the card holder 26 within the slot 24, preventing it from moving. The pressure roller 27, eccentrically arranged inside the card holder 26, is positioned such that when the bridge 1 is not expanding or contracting, the mounting position of the waterstop 25 is at the furthest point from the center of rotation of the pressure roller 27, and both are on the same horizontal line. When the bridge 1 expands or contracts, as the distance between the middle beam 20 and the side beam 21 increases, the waterstop 25 will be stretched, causing it to pull in the opposite direction. As the pressure roller 27 deflects, the position of the clamping foot swings downward, gradually reducing the distance between the clamping foot and the bottom surface of the groove 24. Consequently, the pressure of the pressure roller 27 on the waterstop 25 increases. As the distance between the middle beam 20 and the side beam 21 decreases, the waterstop 25 tends to return to its original length, which pushes the pressure roller 27 to rotate in the opposite direction, causing the clamping foot to swing upward. This gradually reduces the pressure of the pressure roller 27 on the waterstop 25. During the expansion and contraction of the bridge 1, there will be no hard friction or strong pulling between the clamping foot and the groove 24. The movement of the waterstop 25 is effectively restricted between the middle beam 20 and the side beam 21, adapting to the expansion and contraction of the bridge 1. This protects the waterstop 25, extending its service life and improving its performance.

[0038] However, during the expansion and contraction of bridge 1, there is an over-displacement problem, that is, the expansion and contraction of bridge 1 has exceeded the maximum expansion and contraction of expansion structure 2. Therefore, when this happens, the waterstop 25 should be protected. That is, when the clamping foot swings down to the position directly below the center of rotation of the pressure roller 27, the locking mechanism is triggered to release the position lock of the clamping seat 26, so that the clamping seat 26 can move in the clamping groove 24 when subjected to external force. This can extend the expansion and contraction of expansion structure 2 and effectively protect the waterstop 25 from being pulled apart.

[0039] Furthermore, the displacement control system includes a displacement control box 28 connected to the side beam 21. Both ends of the crossbeam 22 are equipped with connecting seats 29. A rubber support 30 is provided between the connecting seat 29 and the inner wall of the displacement control box 28. The connecting seat 29 is slidably arranged on the crossbeam 22. The locking mechanism includes a locking rod 31 slidably arranged on the crossbeam 22. A locking groove 32 is provided on the connecting seat 29. A transmission rod 33 is slidably installed on the middle beam 20. One end of the transmission rod 33 is fixedly connected to the locking rod 31, and the other end is provided with a pressing block 34. A spring is provided between the transmission rod 33 and the middle beam 20. Based on the elastic force of the spring, the transmission rod 33 has a tendency to drive the locking rod 31 to insert into the locking groove 32. Based on the elastic force of the spring, the pressing roller 27 cooperates with the pressing block 34 to limit the length of the waterstop 25 extending out of the card seat 26.

[0040] Specifically, during the expansion and contraction of bridge 1, if over-displacement occurs, the rubber bearing 30 between the crossbeam 22 and the position control system will also be subjected to strong tension. When this tension is excessive, the buffering capacity of the rubber bearing 30 decreases, reducing its buffering and limiting capabilities during bridge 1's expansion and contraction, as well as its load-bearing capacity when vehicles run over the middle beam 20. Therefore, to protect the rubber bearing 30, in this embodiment, a connecting seat 29 connects the rubber bearing 30 and the crossbeam 22. The locking mechanism 26, which is locked in the slot 24, includes a locking rod 31 that slides vertically on the crossbeam 22. A locking groove 32 is provided on the connecting seat 29. When the locking rod 31 is inserted into the locking groove 32, the displacement of the connecting seat 29 on the crossbeam 22 is restricted. A transmission rod 33 is provided on the middle beam 20 corresponding to each locking rod 31. One end of the transmission rod 33 is fixedly connected to the corresponding locking rod 31, and a clamping block 34 is installed at the other end. A spring is provided between the transmission rod 33 and the middle beam 20. Utilizing the spring force, the locking rod 31 tends to engage with the locking groove 32. Furthermore, utilizing the spring force, the clamping block 34 extends partially into the retaining seat 26, confining the retaining seat 26 within the retaining groove 24. For the limiting action between the retaining seat 26 and the retaining groove 24 on the side beam 21, friction or another spring can be used between the retaining seat 26 and the retaining groove 24 to utilize the spring force for restraint. This allows for extending the telescopic range of the telescopic structure 2 to address minor over-displacement issues, such as single-stage and double-stage over-displacement. The displacement of the first level is half that of the second level. Therefore, during the extension of bridge 1, when the position of the clamping foot swings downward to directly below the rotation center of the clamping roller 27, the clamping roller 27, together with the waterstop 25, squeezes the clamping block 34, so that the clamping block 34 releases the restriction on the clamping seat 26. This can further extend the extension of the telescopic structure 2. When no over-displacement problem occurs, based on the elastic force of the spring, the clamping roller 27 can work with the clamping block 34 to limit the stretching of the waterstop 25.

[0041] In the displacement control system, apart from the components mentioned above, all other components are existing technologies and are not shown in the accompanying drawings.

[0042] Preferably, a shielding strip 35 is provided on the waterstop 25 near the card holder 26. The shielding strip 35 is located above the contact part between the waterstop 25 and the card holder 26, and the card holder 26 has a slot 36 for inserting the shielding strip 35. The slot 36 is inclined and the lower end is near the connection point between the shielding strip 35 and the waterstop 25.

[0043] Specifically, in actual application, the contact part between the waterstop 25 and the card holder 26 may move relative to each other. When water accumulates on the waterstop 25, water mixed with impurities may seep into the interior of the card holder 26 or even below the waterstop 25. Therefore, a shielding strip 35 is provided on the waterstop 25 near the card holder 26. The shielding strip 35 can prevent water mixed with impurities from contacting the contact part between the waterstop 25 and the card holder 26. Furthermore, the slot 36 on the card holder 26 for inserting the shielding strip 35 is not connected to the interior of the card holder 26. The slot 36 is located at the lower end near the connection point between the shielding strip 35 and the waterstop 25, which can effectively prevent water and dust from entering and wearing the shielding strip 35, thereby better protecting the telescopic structure 2.

[0044] The foregoing has only described certain exemplary embodiments of the present invention by way of illustration. Undoubtedly, those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the foregoing drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of the claims of the present invention.

Claims

1. A symmetrical, gradually changing span, continuous V-shaped arch bridge, characterized in that, include: The main bridge layout system adopts a multi-span symmetrical gradually changing span arrangement. The overall structure is a multi-segmented segmented structure, with left and right cross-sections, and features pedestrian and vehicle separation, central isolation, and bidirectional drainage cross slopes. The superstructure is a prestressed concrete box girder structure combining a V-shaped rigid frame and arch ribs. The span gradually increases symmetrically from the side span to the middle span, with corresponding gradual beam heights. The box girder adopts a single-box three-cell section. The arch ribs adopt a single-box single-cell double-arch rib arrangement. The local hanging beams adopt a simply supported structure, with one end equipped with an expansion joint to connect with the box girder, and the other end connected to the box girder using a continuous bridge deck structure. The substructure includes solid piers, gravity abutments, and bored pile foundations. The piers, abutments, and pile foundations are matched with the cross-sectional dimensions and pile diameter specifications according to the structural stress gradient. The bridge deck ancillary system includes composite bridge deck paving, drainage system, crash barriers and pedestrian railings; The seismic fortification system is designed according to the seismic fortification standard for highway bridges, matching the corresponding seismic intensity and site category, and is equipped with shock-absorbing pot bearings, seismic blocks on the pier tops and buffer rubber pads between beams. The key sections of the pier body and pile foundation adopt a stirrup-reinforced ductile structure. The corrosion-resistant and durable protection system is designed according to the coastal corrosion environment. The main components are made of graded corrosion-resistant concrete, and the concrete hydration index, chloride ion diffusion coefficient and steel reinforcement protective layer thickness are strictly controlled. Exposed components are divided into atmospheric zone and splash zone with differentiated heavy-duty anti-corrosion coating. The underwater pile foundation is equipped with permanent anti-corrosion steel casing and a special anti-corrosion coating process.

2. The symmetrical, gradually changing span, continuous V-shaped arch bridge according to claim 1, characterized in that, The main bridge structure is designed with symmetrically varying spans from the side spans to the middle span, with span sizes of 50 meters, 60 meters, and 80 meters arranged symmetrically. The bridge is designed in multiple sections to release temperature deformation and shrinkage creep stress. The cross-sections are designed with carriageways, sidewalks, guardrails, and a central median. The carriageways have a 1.5% cross slope, and the sidewalks have a 2.0% cross slope.

3. A symmetrical, gradually changing span, continuous V-shaped arch bridge according to claim 2, characterized in that, Except for the V-shaped rigid frame area which uses ordinary reinforced concrete, the rest of the upper main structure uses prestressed concrete Class A components; the prestressing system uses high-strength low-relaxation steel strands and a group anchoring system, and the prestressing ducts use corrugated metal pipes for drilling and vacuum-assisted grouting process. The 50-meter, 60-meter, and 80-meter spans correspond to the gradually varying arch crown beam heights, and the wall thickness of the box girder and arch rib sections is configured differently according to the stress conditions.

4. A symmetrical, gradually changing span, continuous V-shaped arch bridge according to claim 3, characterized in that, The substructure's abutment and pile foundation adopt different planar dimensions, abutment thickness, and bored pile diameter according to the main beam span and vertical load gradient. The abutment adopts a gravity structure, which is suitable for the bearing capacity and earth pressure resistance requirements of soft soil and coastal sites.

5. A symmetrical, gradually changing span, continuous V-shaped arch bridge according to claim 4, characterized in that, The bridge deck ancillary system uses a composite structure of asphalt concrete and cement concrete for the bridge deck pavement; the bridge deck drainage adopts a combination of longitudinal and transverse drainage, and the collected water is led to the rainwater collection well of the pier through vertical drainage pipes and longitudinal collection pipes; the guardrails and railings are made of steel components and are coated with an overall anti-rust and anti-corrosion coating.

6. A symmetrical, gradually changing span, continuous V-shaped arch bridge according to claim 1, characterized in that, The site of the seismic fortification system is a Class II site, configured according to a seismic fortification intensity of 7 degrees and a seismic measure level of 8 degrees; the plastic hinge zone at the top and bottom of the piers and the limited area at the top of the pile foundation are reinforced with stirrups; a seismic isolation distance is reserved between the bridge end and the top of the pier; and buffer rubber pads are installed between the bridge bodies and between the bridge end and the back wall.

7. A symmetrical, gradually changing span, continuous V-shaped arch bridge according to claim 1, characterized in that, The corrosion and durability protection system is designed differently according to the upper Class II and lower Class III corrosion environments; the box girder, pier, arch seat, pile cap and pile foundation are matched with corrosion-resistant concrete of corresponding strength grade, and the maximum water-cement ratio, alkali content and chloride ion content are strictly controlled, and the minimum protective layer thickness of the steel reinforcement of each component and the 28d chloride ion diffusion coefficient are limited. The atmospheric zone and the splash zone are equipped with a multi-layer heavy-duty anti-corrosion coating system. After sandblasting to remove rust, the steel casing of the underwater pile foundation is coated with epoxy zinc-rich primer and epoxy coal tar topcoat to form a composite anti-corrosion protective layer.

8. A symmetrical, gradually changing span, continuous V-shaped arch bridge according to claim 1, characterized in that, The expansion joint between the hanging beam and the box girder adopts the D160 type expansion joint.

9. A symmetrical, gradually changing span, continuous V-shaped arch bridge according to claim 8, characterized in that, The telescopic structure includes a central beam and two side beams symmetrically arranged on both sides of the central beam. Each side beam has several displacement control systems arranged sequentially along its length. The central beam has several crossbeams arranged sequentially along its length, with each end of a crossbeam corresponding to one of the two displacement control systems. Several anchoring structures are arranged on the side beams. Both the side beams and the central beam have slots, and limiting components are provided in the slots. A waterstop is arranged between the side beams and the central beam, and the locking feet of the waterstop are connected to the limiting components. Due to the limiting function of the limiting component, the clamp on one side of the waterstop is movably restricted to the side beam, and the clamp on the other side is movably restricted to the middle beam.

10. A symmetrical, gradually changing span, continuous V-shaped arch bridge according to claim 9, characterized in that, The limiting component includes a card seat that is slidably arranged in a card slot along the extension and retraction direction of the bridge body. The card seat is locked in the card slot by a locking mechanism. A pressure roller is eccentrically arranged in the card seat. The clamping foot of the waterstop is installed on the pressure roller, and the position of the clamping foot is at the position with the longest straight distance from the center of rotation of the pressure roller. During the stretching stroke of the waterstop, the pressure roller gradually rotates to press the waterstop. When the clamping foot is positioned directly below the rotation center of the pressure roller, the locking mechanism releases the position lock of the clamping seat based on the squeezing action of the waterstop.

Images