Detachable stud connecting piece steel plate concrete bridge tower construction system

Abstract

The invention discloses a detachable stud connecting piece steel plate concrete bridge tower construction system, and belongs to the technical field of bridge engineering and fabricated structure connection. The system comprises a bolt-sleeve combined type stud connecting piece applied to the double-steel-plate wall of the steel plate concrete bridge tower and a bridge tower modular construction method based on the connecting piece. The connecting piece is composed of an outer sleeve welded to the inner side of the steel plate and a detachable inner high-strength bolt. And the rod part of the internal bolt is matched with the internal thread, and the end part is provided with an expanded head or a groove-shaped anchoring part. And internal bolts are reversely screwed out by using a special tool through the reserved manhole of the steel plate, so that the steel plate is reversibly separated from the concrete. The bridge tower section steel shell constructed based on the connecting piece and the concrete core block achieve modular assembly and local replacement, the maintainability of the whole life cycle of the bridge tower and the material recoverability are remarkably improved, and the bearing performance and the green sustainable requirement are both considered.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of bridge engineering and civil engineering structure connection, in particular to a detachable stud connector applied to a steel plate concrete bridge tower and a bridge tower modular construction system based on the connector, belonging to the technical field of fabricated steel-concrete composite structure, reversible construction and green demolition. BACKGROUND

[0002] Steel-concrete composite structure bridges are widely used in long-span bridges, especially in cable-stayed bridges and suspension bridges, due to their advantages of both steel structures and concrete structures. In recent years, new types of composite bridge towers such as double-steel plate concrete bridge towers and steel box concrete cable towers have gradually matured. They work together with internal concrete through double or multi-layer steel plates, which can reduce the cross-sectional size of components, improve the industrialization degree of construction and durability. Among them, the steel plate concrete bridge tower represented by the Nanjing Yangtze River Fifth Bridge realizes rapid construction and excellent overall stress performance through factory prefabricated steel shells and on-site concrete pouring.

[0003] In existing steel-concrete composite structures, the connection between steel plates and concrete is mostly in the form of welded studs, perforated steel plates, stud-steel bar combinations, etc. Numerous studies have shown that ordinary welded studs have good shear transfer capacity and ductility in composite beams and towers, and their shear bearing capacity and deformation performance are closely related to parameters such as concrete strength, stud diameter, and height-to-diameter ratio. However, such studs are usually permanently welded to the steel plate by stud welding equipment, and the stud body forms an integral whole with the concrete after pouring. Once the structure needs to be repaired, modified, or demolished, it can only be demolished by blasting, large-volume cutting, or crushing the entire steel-concrete structure, which not only has high construction risks and costs, but also makes it difficult to efficiently classify and recycle steel and concrete.

[0004] In response to the "double carbon" target and the requirements of green and sustainable development of infrastructure, in recent years, the academic and engineering communities have begun to focus on detachable shear connectors for fabricated steel-concrete composite beams. Some literature suggests using bolts-nuts, pins, and prefabricated sleeves to achieve detachable connection between steel beams and concrete slabs in composite beams, thereby facilitating bridge deck slab repair or beam reuse. Such detachable shear connectors usually work in horizontal beam components and mainly bear shear forces, and some also bear tensile or compressive bending forces. However, existing research mainly focuses on horizontal components such as bridge deck composite beams and floor slabs, with shear under repeated loads being the main force in the connection area, and the connector size is relatively small, and it is mostly subjected to unidirectional or in-plane forces.

[0005] For tall, heavy-duty, vertical structural members like steel-concrete composite bridge towers, their cross-sections are often hollow box-shaped or multi-chambered box-shaped. The double steel plate walls are reliably connected to the concrete core through internal studs, bearing complex combined compressive, bending, and shear forces under vertical dead loads, vehicle loads, and the effects of wind, earthquakes, and temperature gradients. In existing publicly available technologies, the steel-concrete composite bridge towers mostly still use traditional welded studs or perforated plates for internal connections, forming permanent and irreversible connections. While published patents or documents such as "Double Steel Plate-Ultra-High Performance Concrete Composite Bridge Tower and its Prefabricated Construction Method" have innovated in the structural layout and assembly construction of composite bridge towers, they still use permanent welded studs or equivalent rigid connectors between the steel plates and concrete, failing to achieve detachability of the connectors themselves, and further failing to endow the bridge tower with the ability for "reversible construction" and "segmented recycling."

[0006] Furthermore, existing research on detachable shear connections largely applies traditional bolt-sleeve or precast anchor techniques to beam-slab composite interfaces, primarily targeting relatively thin concrete slabs or UHPC composite layers. Directly applying these techniques to steel-concrete bridge towers would face the following problems:

[0007] Stress mismatch: The connectors in the bridge tower not only bear in-plane shear force, but also participate in the combined compression-bending-shear stress under vertical pressure and tower bending moment. Ordinary beam detachable connectors are difficult to meet the safety reserve under the coupled action of high axial compression and large bending moment.

[0008] The construction and installation are challenging: the internal space of the tower is narrow and the operating height is high. Existing detachable beam-slab connectors are mostly operated from the slab surface, lacking detailed structural designs for internal maintenance and disassembly of the tower.

[0009] Lack of a complete life-cycle dismantling path: Existing solutions typically only consider the replacement of local panels or the dismantling of beams, without systematically designing a controllable separation path and operation process for the dismantling of the entire bridge tower segment or the whole tower decades later.

[0010] In summary, existing technologies either employ a steel plate concrete bridge tower solution with permanent welded stud connections, which can only be dealt with by blasting or overall cutting when the structure is scrapped or undergoes major renovations, resulting in huge waste of resources and environmental burden; or they propose a solution for detachable shear connection components for composite beams, but have not solved the key technical challenges of tall vertical composite bridge towers in terms of complex stress, confined space, and reversible disassembly and assembly throughout their entire lifespan.

[0011] Therefore, there is an urgent need for a detachable stud connector and its supporting construction system specifically developed for steel plate concrete bridge towers. This would enable the bridge towers to maintain the high-efficiency load-bearing performance of the steel-concrete composite structure during service, and to achieve controllable separation and high-value recycling of the steel plate and concrete during maintenance, reinforcement and decommissioning stages. This would truly achieve the technical goal of "building large composite structures quickly, dismantling them easily, and recycling materials". Summary of the Invention

[0012] This invention addresses the shortcomings of existing steel-plate concrete bridge towers where the stud connections are permanent and non-removable. It proposes a detachable "bolt-sleeve" composite stud connection and a corresponding modular construction system for the bridge tower. The aim is to simultaneously solve the following technical problems: ensuring the overall load-bearing performance of the steel-plate concrete bridge tower under complex combinations of vertical pressure, bending moment, and shear force, while achieving reliable and detachable connections between the steel plate and concrete. A modular steel-shell-concrete core structure system suitable for double-steel-plate concrete bridge towers is established, enabling "minimally invasive" local repairs and reinforcement during service, and allowing for segmented, material-based green dismantling and efficient recycling at the end of the service life. A complete and feasible construction and dismantling method is developed, encompassing factory prefabrication, on-site assembly, operational maintenance, and end-of-life dismantling, clearly defining key structural elements and processes such as connector arrangement, inspection hole placement, and dismantling paths.

[0013] To solve the above problems, the technical solution proposed by this invention includes:

[0014] "Bolt-Sleeve" Composite Detachable Stud Connector: By welding and fixing the outer sleeve (2) to the inside of the steel plate (1), it exists as an "embedded base" of the steel plate throughout its entire life cycle; through the detachable threaded connection between the inner bolt (3) and the outer sleeve (2), reversible mechanical anchoring with the concrete core (4) is achieved; the operating end (34) cooperates with the inspection hole (5) arranged on the steel plate, so that the connector can be safely and conveniently operated from inside the tower leg during installation and removal.

[0015] The stud arrangement and maintenance system applicable to steel plate concrete bridge towers: According to the cross-sectional dimensions, wall thickness and internal force distribution of the bridge tower, the external sleeves (2) are arranged in a certain grid on the inner side of the steel plate shell (6) of the tower leg, and the density is appropriately increased in the bending moment and shear force concentration areas; vertical or horizontal maintenance channels are set in the tower leg, maintenance holes (5) corresponding to the connecting parts are opened on the steel plate, and end caps (9) and sealing structures (10) are configured to take into account both operability and durability.

[0016] Modular structure and construction method of bridge tower segments: The bridge tower is divided into several standard segments along the height direction. The overall forming of the steel plate shell (6) and the welding of the outer sleeve (2) are completed in the factory first. After the segment steel shell is transported to the site, the tower legs are erected and assembled. Then, the internal bolts (3) are installed through the inspection hole (5), and then concrete is poured to form concrete core blocks (7). When partial replacement or overall removal is required, the internal bolts (3) are removed by segment or area to achieve mechanical separation of the steel plate shell (6) and concrete core blocks (7) to avoid explosion or overall cutting.

[0017] Compared with the prior art, the present invention has at least the following beneficial effects:

[0018] Achieving reversible connection of large composite bridge towers: By setting an external sleeve (2) on the inside of the steel plate and using internal bolts (3) to form a mechanical anchor with the concrete core (4), the steel-concrete interface of the bridge tower is transformed from "permanent welded studs" to "detachable composite studs", providing a reversible connection path for the first time for tall composite bridge towers.

[0019] Balancing load-bearing capacity and disassembly: The anchoring section (31) of the internal bolt (3) adopts the form of enlarged head, multi-faceted or toothed wedge, which can achieve greater shear and pull-out resistance without significantly reducing the load-bearing capacity of the connection; By reasonably designing the wall thickness and thread fit length of the external sleeve (2), the connector still has sufficient rigidity and fatigue life under the combined action of vertical pressure, bending and shear.

[0020] Support for “minimally invasive” repairs and local upgrades: When the steel plates of the bridge tower are corroded or the concrete is severely deteriorated, only the internal bolts (3) corresponding to the damaged area can be removed, and the local steel plate shell (6) or local concrete core block (7) can be lifted off to achieve targeted repair or replacement, avoiding large-scale demolition, saving costs and reducing the impact on traffic operation.

[0021] Achieving high-value material recycling and green demolition: During the demolition phase after the structure reaches its design life, the internal bolts (3) can be removed in sections along the height of the bridge tower, the steel plate shell (6) can be lifted off as a whole and reused or recycled, and the concrete core blocks (7) can be crushed in a concentrated manner to prepare recycled aggregate, which greatly reduces solid waste emissions and meets the requirements of green and low-carbon development.

[0022] Construction safety and maintenance convenience: By setting up inspection holes (5) and inspection channels inside the tower limbs, the installation and disassembly of the connectors can be carried out in a closed space, avoiding high-altitude external operations; in conjunction with end caps (9) and sealing structures (10), rainwater, chloride ions and other substances can be effectively prevented from entering the connection area, improving durability and reducing maintenance difficulty. Attached Figure Description

[0023] Figure 1This is a schematic diagram of a typical arrangement of the detachable stud connector of the present invention in the double steel plate wall of a steel plate concrete bridge tower;

[0024] Figure 2 A cross-sectional view of a detachable bolt-sleeve composite stud;

[0025] Figure 3 A schematic diagram showing the factory prefabrication of steel plate shell segments and the welding arrangement of external sleeves;

[0026] Figure 4 A schematic diagram illustrating the on-site assembly, internal bolt installation, and concrete pouring process of bridge tower segments;

[0027] Figure 5 A schematic diagram illustrating the operation of partially disassembling and replacing steel plates or concrete core blocks of a bridge tower.

[0028] Explanation of markings in the diagram: 1—Steel plate; 2—Outer sleeve; 21—Flange; 22—Sleeve cavity / internal thread section; 3—Internal bolt; 31—Anchoring section / enlarged head; 32—Bolt shank; 33—Threaded section; 34—Operating end; 4—Concrete core / partial concrete core block; 5—Inspection hole; 6—Steel plate shell (tower leg steel shell segment); 7—Concrete core block (tower leg concrete segment); 8—Temporary positioning component / support; 9—Inspection hole end cap; 10—Sealing ring or waterproof structure. Detailed Implementation

[0029] The following detailed embodiments, in conjunction with the above-mentioned accompanying drawings, provide a detailed description of the structural form, parameter range, and construction / demolition steps of the present invention, but do not limit the scope of protection of the present invention.

[0030] I. Example 1: Basic Structure of Detachable "Bolt-Sleeve" Composite Stud

[0031] See Figure 2 The detachable stud connector in this embodiment is mainly composed of an outer sleeve (2) and an inner bolt (3), used to connect the steel plate (1) and the concrete core (4).

[0032] External sleeve (2) structure

[0033] The outer sleeve (2) is a cylindrical steel component, preferably made of structural steel with the same or similar strength grade as the steel plate (1), such as Q345, Q355, or Q420. The outer diameter of the sleeve... The wall thickness is typically 25–60 mm. The thickness is 4–10 mm to ensure sufficient load-bearing capacity and weldability. One end of the sleeve is provided with a radially extending flange (21), the flange thickness being... Take 6–12 mm, diameter The flange should be 10–30 mm larger than the outer diameter of the sleeve. The outer edge of the flange can be chamfered to reduce stress concentration. An axial sleeve cavity (22) is formed inside the sleeve, with internal threads machined on the inner wall. The thread diameter matches the threaded section (33) of the internal bolt (3), and a metric coarse thread, such as M20–M36, is preferred. Effective thread length… The diameter should generally be no less than 1.2 times the bolt diameter to ensure sufficient tensile and shear bearing capacity. A locating shoulder or weld bevel may be provided on the outer wall of the sleeve near the steel plate to control welding quality and weld shape.

[0034] Connection between outer sleeve (2) and steel plate (1)

[0035] The steel plate (1) is one of the double steel plate walls of the bridge tower, and its thickness is generally 20–40 mm. The flange (21) is tightly attached to the inner side of the steel plate (1) and fixed by welding with a circumferential weld or multiple fillet welds. The weld height is designed according to the stress conditions and fatigue level, and is generally not less than 6 mm. Before welding, a circular hole with a diameter equal to or slightly smaller than the outer diameter of the sleeve is pre-drilled on the steel plate (1) so that the sleeve (2) can be partially inserted into the thickness of the steel plate, thereby reducing the eccentricity of the connecting parts and improving the rigidity.

[0036] Internal bolt (3) structure

[0037] The internal bolt (3) is made of high-strength bolt material, such as grade 8.8 or 10.9 alloy structural steel. The bolt comprises: an anchoring section / enlarged head (31), a bolt shank (32), a threaded section (33), and an operating end (34). The threaded section (33) mates with the internal thread of the outer sleeve (2), preferably with a medium fit grade to balance assemblability and anti-loosening performance. The anchoring section (31) is located at the end furthest from the operating end (34) and extends into the concrete core (4). Its outer diameter... Compared to bolt shank diameter There is some magnification, which usually satisfies The anchoring section can be made into a mushroom-shaped or multi-faceted anchor body, and its surface can be roughened or have ribs added to enhance its interlocking with concrete. To improve the pull-out performance, a certain length of longitudinal ribs or spiral ribs can be set on the bolt shank (32) near the anchoring section. The operating end (34) is a wrench bearing part that is easy to disassemble and assemble, and can be in the form of internal hexagonal hole, internal spline, plum blossom hole or transverse pin hole to adapt to different disassembly and assembly tools.

[0038] Protective and sealing structure

[0039] A sealing ring or waterproof adhesive (10) is installed around the contact point between the steel plate (1) and the outer sleeve (2) to prevent external moisture and chloride ions from entering the threaded area and causing corrosion. An inspection hole end cap (9) is installed on the outer surface or inner side of the steel plate and is fixed with bolts or pins. A sealing gasket is attached to the back of the end cap to ensure the airtightness and watertightness of the bridge tower.

[0040] II. Example 2: Arrangement and Working Mechanism of Connectors in Steel Plate Concrete Bridge Towers

[0041] See Figure 1 This embodiment describes the arrangement of the detachable stud connector in the double steel plate wall of the bridge tower.

[0042] Arrangement principles

[0043] Along the height of the bridge tower, the connectors can be arranged in a regular grid in the middle of the tower leg, such as a vertical spacing of 300–600 mm and a circumferential spacing of 300–600 mm. In areas with concentrated internal forces, such as the base of the tower leg, the crossbeam-tower leg connection area, and near the cable saddle, the connectors can be arranged more densely, with the spacing reduced to 200–300 mm. Connectors can be arranged on both the inner and outer steel plates (1), with the connectors arranged longitudinally in a staggered manner to improve the bending and shear resistance of the cross section. When arranging the connectors, attention should be paid to the spatial conflict with the main reinforcement, prestressed ducts, and maintenance passages, and the positions should be optimized through three-dimensional modeling.

[0044] Working mechanism

[0045] When the bridge tower is subjected to vertical pressure and bending moment, the concrete core (4) and the steel plate (1) share the compressive and tensile stresses. The bond-locking between the anchorage section (31) of the internal bolt (3) and the surrounding concrete provides the interface shear force transfer. Under the action of temperature gradient and creep shrinkage, the deformation difference between the steel plate and the concrete is coordinated by the connector. The outer sleeve (2) and the internal bolt (3) work together to limit relative slippage. Under the action of strong earthquake or extreme wind load, the connector can provide a certain degree of ductility. After the concrete around the anchorage section (31) is locally crushed or cracked, the internal bolt (3) still maintains its integrity, which is beneficial to the seismic safety of the bridge tower. Under the demolition condition, by removing the internal bolt (3), the mechanical locking on the steel-concrete interface is broken, and the steel plate shell (6) of the bridge tower can slide and separate relative to the concrete core block (7).

[0046] III. Example 3: Factory-prefabricated steel plate shell segments ( Figure 3 )

[0047] See Figure 3 This embodiment describes the prefabrication process of bridge tower steel plate shell segments in a factory environment.

[0048] Steel plate shell forming

[0049] Based on the design cross-section of the bridge tower, multiple steel plates (1) are processed by bending, rolling or welding to form a closed or partially closed box-shaped steel plate shell (6). Temporary positioning components / supports (8) are set up during the assembly process to ensure that the cross-sectional shape, diagonal and wall thickness meet the tolerance requirements.

[0050] External sleeve welding

[0051] Mark the design layout lines on the inner side of the steel plate (1) and use CNC cutting equipment to make holes at the corresponding positions. The hole diameter is slightly smaller than the outer diameter of the outer sleeve (2) to achieve an interference fit or a small clearance fit. Insert the outer sleeve (2) into the hole so that the flange (21) is tightly against the inner side of the steel plate, and adjust the sleeve axis to be perpendicular to the plane of the steel plate. Use CO2 gas shielded welding or gas metal arc welding to weld the flange (21) to the steel plate (1). Butt welding or multi-pass fillet welding can be selected according to the fatigue level. If necessary, perform non-destructive testing on the weld. After welding, clean the inner thread of the sleeve to ensure that the thread is intact, and re-tapping if necessary.

[0052] Corrosion prevention and sealing

[0053] After welding, the steel plate shell (6) and the outer sleeve (2) are sandblasted and coated with anti-corrosion primer and topcoat. A sealing ring or waterproof adhesive (10) is installed on the side of the outer sleeve (2) near the steel plate to provide a certain degree of waterproof performance before the internal bolts (3) are installed on site. For sleeves where the internal bolts are not installed temporarily, temporary plastic plugs can be installed to prevent dust and moisture from entering during transportation.

[0054] IV. Example 4: On-site assembly and concrete pouring ( Figure 4 )

[0055] See Figure 4 This embodiment describes the entire process of bridge tower segments on the construction site, from the erection of the steel shell tower to the pouring of concrete.

[0056] Steel shell segment hoisting and assembly

[0057] The prefabricated steel plate shell segments (6) are transported to the construction site and hoisted section by section along the bridge tower axis using large lifting equipment. The segments are assembled by full-welded butt joints, circumferential welds, or high-strength bolts to form a continuous tower limb steel shell. During the assembly process, temporary supports and internal supports (8) are used for correction to ensure that the overall verticality of the tower limb and the local geometric dimensions meet the design requirements.

[0058] Maintenance access and access hole settings

[0059] Vertical ladders, platforms, and passageways are installed inside the tower limbs to ensure that construction personnel can reach the connection areas of each floor. Inspection holes (5) are made on the steel plate (1) at the designed locations, with a diameter generally of 60–120 mm, to facilitate the insertion of wrenches or socket tools. Reinforcing ring plates are welded around the inspection holes to restore the local rigidity of the steel plate. The layout of the inspection holes (5) should correspond to the external sleeves (2) to ensure a smooth installation path for the internal bolts (3). If necessary, eccentric sleeves or flexible extension tools can be used to adapt to local obstruction.

[0060] Internal bolt installation and pre-tightening

[0061] After the steel shell of the tower limb is stabilized, the internal bolts (3) are inserted one by one into the external sleeve (2) through the inspection hole (5) from the construction platform inside the tower, so that the threaded section (33) engages with the internal thread. The specified preload is applied from the operating end (34) using a torque wrench or electric torque tool. The magnitude of the preload is determined based on the design shear force and anti-slip calculation results to ensure that the steel plate and the external sleeve are tightly connected before the concrete is poured. For some key parts, a deformation design of the torsion shear type high-strength bolt structure can be adopted so that the preload can be judged by the tail end fracture.

[0062] Concrete pouring and curing

[0063] After all internal bolts (3) are in place and inspected and approved, install the internal formwork and temporary supports (8) of the tower limb, and arrange vertical and horizontal reinforcement. Concrete is poured in layers from bottom to top using a pumping method. The concrete strength grade is generally C50–C60, or UHPC is used to further reduce the cross-sectional size. During the pouring process, the area near the connector should be vibrated to ensure that the concrete around the anchor section (31) is dense and free of honeycomb pitting. After the concrete reaches the demolding strength, remove the inner formwork and temporary supports, and continue curing until the design age strength.

[0064] Inspection hole sealing

[0065] After the concrete strength meets the design requirements and the inspection is completed, the end cap (9) on the surface of the inspection hole (5) is assembled into place. The end cap is fixed by peripheral bolts or welding, and a sealing gasket or sealant is applied to its back. The inner and outer surfaces of the tower are then coated with the final anti-corrosion coating to complete the construction of the superstructure of the bridge tower.

[0066] V. Example 5: Partial Repair, Replacement, and Complete Tower Dismantling Figure 5 )

[0067] See Figure 5 This embodiment illustrates the application of the present invention during the operation and decommissioning period of bridge towers.

[0068] Partial steel plate replacement

[0069] When severe corrosion or fatigue cracks are found in a local steel plate (1), a temporary working platform and support (8) can be erected inside the tower leg first, and the auxiliary components on the outside of that area can be removed. Open the end cover (9) of the inspection hole in the corresponding area, and use a special torque tool to remove the internal bolts (3) one by one through the inspection hole (5) to disconnect the local connection between the steel plate (1) and the concrete core block (7) in that area. Under the premise of ensuring overall stability, cut or remove the damaged steel plate, hoist the new precast steel plate into place, and re-weld the external sleeve (2) or use the external sleeve that has been preset in the replacement segment. Reinstall the internal bolts (3), close the inspection hole (5), and complete the local replacement.

[0070] Partial concrete core block repair / replacement

[0071] If a concrete core block (7) within a certain height range is severely deteriorated due to fire, alkali-aggregate reaction, or other reasons, the internal bolts (3) within that range can be removed from the tower in a similar manner to release the bond-mechanical connection between the steel plate shell (6) and the concrete core block (7). The deteriorated concrete can be removed or cut into sections and hoisted out by opening a temporary opening at the top or side of the tower. After inspecting and treating the inside of the steel plate shell (6) for corrosion protection, new concrete can be poured or precast concrete core blocks can be installed, and the internal bolts (3) can be reinstalled.

[0072] whole tower segmental dismantling and material recycling

[0073] After the bridge reaches its designed service life, it can be dismantled from top to bottom in segmental order. For each segment, a temporary support (8) is first erected inside the tower limb, and the internal bolts (3) of the segment and a certain range below it are removed through the inspection hole (5). After the steel-concrete interface connection is disconnected, the steel plate shell (6) and the concrete core block (7) are separated by cutting or dismantling: the steel plate shell (6) is cut into large plates that are easy to transport, and hoisted to the ground for classification, recycling or renovation and reuse; the concrete core block (7) is hoisted out as a whole or in sections and sent to a recycled aggregate processing plant for crushing and screening, and used for road base, recycled concrete, etc.

[0074] Compared to traditional blasting or monolithic cutting, this method significantly reduces the risks of noise, dust, and splashes, making it easier to implement green demolition in urban environments.

[0075] VI. Optional Variations and Extended Applications

[0076] Optimization of connector geometry and materials

[0077] An elliptical or polygonal outer sleeve (2) can be used to accommodate local space constraints. In highly corrosive environments, stainless steel or composite coating materials can be used to improve durability. For high fatigue areas, a transition fillet or reinforcing plate can be provided between the outer sleeve (2) and the steel plate (1) to reduce stress concentration.

[0078] Seismic and ductile design

[0079] In earthquake-fortified areas, the preload of the internal bolts (3) can be appropriately reduced or controllable slip shims can be used to allow controlled slippage at the interface during a major earthquake, thereby dissipating energy. Alternatively, a locally yieldable section design can be adopted near the anchorage section (31) to ensure that the connection is mainly subjected to ductile failure under extreme conditions, thus avoiding brittle shear failure.

[0080] Extension to other structural forms

[0081] The detachable stud connectors and modular construction concept of this invention can also be applied to structures such as steel box concrete main beams, steel-concrete composite piers, and prefabricated building core tubes, to achieve a wider range of "reversible construction" and high-value material recycling.

[0082] The above embodiments are merely illustrative of the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Various equivalent substitutions or modifications made by those skilled in the art without departing from the spirit and substance of the present invention should fall within the scope of protection of the present invention.

Claims

1. A detachable stud connector, characterized in that, For shear force transfer and coordinated operation between steel plate and concrete in steel plate-concrete composite structures, comprising: (a) an outer sleeve (2) having a radially extending flange (21) at one end, the flange (21) being fitted and welded to the inner side of the steel plate (1); the interior of the outer sleeve (2) forming an axially penetrating sleeve cavity (22), the inner wall of the sleeve cavity being provided with internal threads; (b) The internal bolt (3) is a high-strength bolt. The outer surface of its shank (32) is provided with an external thread that mates with the internal thread. One end of the bolt is provided with an operating end (34) that applies pre-tightening force to the steel plate through the sleeve (2), and the other end is provided with an enlarged head or anchoring section (31) that extends into the concrete core (4). After the internal bolt (3) is screwed into the outer sleeve (2) and tightened, the enlarged head or anchoring section (31) and the concrete core (4) form a mechanical engagement, so as to achieve a reliable connection between the steel plate (1) and the concrete core (4) under the combined action of vertical bending and shearing. When disassembly is required, the internal bolt (3) can be removed from the outer sleeve (2) by applying a reverse torque through the operating end (34), thereby terminating the connection between the steel plate (1) and the concrete core (4).

2. The detachable stud connector according to claim 1, characterized in that: The operating end (34) is at least one of an internal hexagonal hole, a plum blossom hole, or a transverse slot structure. The steel plate (1) is provided with an inspection hole (5) at the position corresponding to the outer sleeve (2) so that a wrench or special disassembly tool can pass through the inspection hole (5) and cooperate with the operating end (34) to complete the installation and disassembly of the internal bolts (3).

3. The detachable stud connector according to claim 1 or 2, characterized in that: The outer sleeve (2) is provided with an annular sealing structure at the end near the steel plate (1), including a sealing ring (10) and / or waterproof sealant, to seal the sleeve cavity (22) and the internal thread; the inspection hole (5) is closed by bolting the end cap (9) in the use state to improve durability and corrosion resistance.

4. The detachable stud connector according to any of the preceding claims, characterized in that: The enlarged head or anchoring section (31) is one or a combination of the following: mushroom head type, disc type, multi-faceted anchoring head, transverse perforated anchoring section, or toothed wedge-shaped anchoring section, and its outer diameter With bolt shank diameter The ratio satisfies .

5. The detachable stud connector according to any of the preceding claims, characterized in that: The steel plate (1) is one or both of the inner and outer steel plates in the double steel plate wall of the steel plate concrete bridge tower. The internal bolts (3) are arranged in rows and columns along the height direction and cross-sectional width direction of the bridge tower to bear the combined force under vertical pressure, bending moment and shear force, and work together with the precast steel shell of the bridge tower segment and the cast-in-place concrete core (4).

6. A steel plate concrete bridge tower segment module employing the detachable stud connector as described in any one of claims 1-5, comprising: A double or multi-layer steel plate shell (6) arranged circumferentially along the cross-section of the bridge tower, and a concrete core block (7) formed by casting in the cavity enclosed by the steel plate shell (6), characterized in that: (a) a plurality of external sleeves (2) are pre-welded on the inner side of the steel plate shell (6); (b) after the steel plate shell (6) is assembled and positioned, the internal bolts (3) are screwed into each external sleeve (2) through the inspection hole (5) from the inside of the bridge tower and tightened, and then concrete is poured into the inside of the steel plate shell (6) to form a concrete core block (7), so that the anchoring section (31) of the internal bolts (3) is embedded therein; (c) when replacement or upgrade is required, the steel plate shell (6) and the concrete core block (7) are separated by disassembling the internal bolts (3), thereby realizing the partial replacement of the steel plate shell (6) or the concrete core block (7) in the bridge tower segment module.

7. The steel plate concrete bridge tower segment module according to claim 6, characterized in that: Near the vertical splicing joints or transverse construction joints of adjacent segments in the height direction of the bridge tower, increase the arrangement density of the detachable stud connectors, and set up vertical or horizontal passages for passage and maintenance in the tower limbs so that the internal bolts (3) can be repeatedly disassembled and reassembled throughout the entire life cycle.

8. A construction method for a steel plate concrete bridge tower with detachable stud connectors, characterized in that, Includes the following steps: S1. The steel plate shell (6) of the bridge tower segment is prefabricated in the factory, and the outer sleeve (2) is welded on its inner side according to the design grid, and the inner thread of the sleeve is formed; S2. Multiple prefabricated steel plate shell (6) segments are transported to the site, and the segment steel shell is assembled by welding or bolting to form a closed or semi-closed tower leg steel shell; S3. The internal bolts (3) are screwed into the corresponding outer sleeves (2) one by one through the inspection hole (5) on the steel shell and a pre-tightening force is applied; S4. Concrete is poured inside the steel shell to form a concrete core block (7) that engages with the anchoring section (31) of the internal bolts (3), and the overall stressed steel plate concrete bridge tower segment is obtained; S5. During the operation period of the bridge tower, when it is necessary to replace, reinforce or dismantle a part, the internal bolts (3) of the corresponding area are removed through the inspection hole (5) to separate the steel plate shell (6) from the concrete core block (7) and realize modular disassembly and assembly.

9. The construction method according to claim 8, characterized in that: When the bridge tower reaches its design service life or suffers major structural damage, the internal bolts (3) are disassembled in sections and segments, and the steel plate shell (6) and concrete core block (7) are hoisted and separated. The steel plate shell (6) can be reused after simple repair, and the concrete core block (7) can be crushed in a centralized manner and used as recycled aggregate or other recycled materials, so as to realize the high-value recycling of materials throughout the entire life cycle of the structure.

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