Ribbed pre-tensioning pre-stressed UHPC bridge deck slab prefabricating die platform and construction method thereof

Abstract

The invention discloses a ribbed pre-tensioning pre-stressed UHPC bridge deck slab prefabricating die platform and a construction method thereof.The ribbed pre-tensioning pre-stressed UHPC bridge deck slab prefabricating die platform comprises a foundation structure, a lower supporting mechanism and an upper supporting mechanism which are fixedly connected in sequence from bottom to top, and the foundation structure is of a groove cavity structure formed by integrally enclosing a pedestal base, a pedestal reaction wall and a pedestal force transmission beam; the pedestal base is arranged on a foundation; the lower supporting mechanism is installed on the top of the foundation structure and comprises a plurality of rows of middle stand columns and symmetrical side stand columns on the two sides, and a cooperative supporting system is formed. The upper supporting mechanism is fixed to a top cross beam of the lower supporting mechanism through a connecting assembly, multiple pairs of longitudinal beams matched with UHPC bridge deck slab longitudinal ribs are arranged at the top of the cross beam, a formwork assembly is assembled at the tops of the longitudinal beams, and supporting beam auxiliary supporting formworks are arranged at the two ends of the formwork assembly. The prefabricated mold table is provided with a self-balancing bearing system and can adapt to a complex foundation, cost reduction and speed increase are achieved, the rigidity of the elastic connecting system is adjustable, the vibration compactness can be guaranteed, meanwhile, the height of the cross beam can be adjusted to guarantee the installation precision, and then the prefabricated quality is improved.

Description

Technical Field

[0001] This invention belongs to the field of bridge construction technology, and more specifically, relates to a precast formwork platform for ribbed prestressed UHPC bridge deck and its construction method. Background Technology

[0002] With the continuous upgrading of infrastructure construction in my country and the accelerating pace of industrialization and prefabrication in the building industry, the market has placed increasingly stringent demands on the comprehensive performance, molding quality, production efficiency, and precision of precast concrete components. Ultra-high performance concrete (UHPC), with its superior compressive strength, ultra-high toughness, excellent durability, and low permeability, has become a core material for manufacturing high-performance, lightweight, and long-life precast components, and its application in engineering fields is becoming increasingly widespread. In the production of prestressed concrete components using the pre-tensioning method, the advantages of UHPC are particularly prominent: it can significantly reduce the cross-sectional dimensions of components, lower self-weight, and expand applicable spans, while also greatly improving the crack resistance and long-term durability of the structure. Therefore, it is especially suitable for scenarios with stringent performance requirements, such as large-span bridge slabs, heavy-duty industrial floor slabs, and special structural components.

[0003] Among them, prestressed high-pressure precast concrete (UHPC) bridge decks with longitudinal stiffeners and end crossbeams (hereinafter referred to as "ribbed prestressed UHPC bridge decks") are a typical form of precast component that combines high performance and practicality. The longitudinal stiffener design can significantly improve the bending stiffness and load-bearing efficiency of the deck, while the end crossbeams facilitate the lateral connection and overall coordinated stress distribution between multiple bridge decks. The application of prestress further optimizes the structural performance, making this type of component show broad application prospects in composite beam bridges. However, the flat formwork or simple grooved formwork used in traditional prestressed precast processes is difficult to accurately adapt to the complex three-dimensional geometry formed by the longitudinal stiffeners and end crossbeams. For UHPC components with extremely high dimensional accuracy requirements, traditional formwork is prone to deformation problems such as inadequate formwork support and insufficient stiffness in key areas such as the narrow and deep groove areas of the longitudinal stiffeners and the lateral anchorage areas of the end crossbeams, directly affecting the dimensional accuracy and appearance quality of the components. Therefore, when the prestressed process is applied to the large-scale production of ribbed UHPC bridge decks, the structural defects and insufficient adaptability of traditional precast molds become prominent bottlenecks, which seriously restrict the standardization, large-scale production and high-quality development of this type of high-performance component. Summary of the Invention

[0004] To address the aforementioned deficiencies or improvement needs of existing technologies, this invention provides a precast formwork platform for ribbed prestressed UHPC bridge decks and its construction method. By constructing a self-balancing prestressed load-bearing system through the foundation structure, during the UHPC bridge deck forming, the prestressed steel bars are transferred to the reaction wall of the platform via anchors and support beams, and finally to the platform base and force transmission beams, forming a closed-loop force path. Utilizing the characteristic that the prestress at both ends is similar in magnitude but opposite in direction, the platform achieves load self-balancing, eliminating the need for the foundation to bear all horizontal tension reaction forces, significantly reducing dependence on the foundation bearing capacity, adapting to complex geological conditions, reducing the scale of foundation construction, decreasing material consumption and labor costs, and shortening the construction period. Simultaneously, the formwork platform adopts a separate layout for the upper and lower support mechanisms, flexibly connected by bolt + spring washer elastic connection components. The exposed length of long bolts can be adjusted, and the connection stiffness can be precisely controlled to adapt to the operation of attached vibrators, ensuring the compaction of the UHPC. It can also simultaneously correct the height of the crossbeams, ensuring they are at the same level, laying the foundation for formwork laying and precise component forming.

[0005] To achieve the above objectives, according to one aspect of the present invention, a precast formwork platform for ribbed prestressed UHPC bridge deck is provided, comprising a foundation structure, a lower support mechanism, and an upper support mechanism; wherein... The basic structure includes a pedestal base, a pedestal reaction wall, and a pedestal force transmission beam. The pedestal base is set on the foundation. The pedestal reaction wall is integrally set at the top of both ends along the length direction. The pedestal force transmission beam is integrally set at the top of both ends along the width direction of the pedestal base. The two ends of the pedestal force transmission beam are fixedly connected to the pedestal reaction wall. The pedestal base, the pedestal reaction wall, and the pedestal force transmission beam together form a cavity structure. The lower support mechanism is fixedly installed on the top of the foundation structure. It includes a central column and side columns. Multiple rows of central columns are arranged in the middle of the groove structure above the pedestal base along the length of the pedestal base, and a row of side columns is symmetrically arranged on both sides of the multiple rows of central columns to form a cooperative support system. The upper support mechanism is fixedly installed on top of the lower support mechanism. It includes a connecting component, a crossbeam, a longitudinal beam, a support beam, and a template assembly. Each row of central columns and side columns has a crossbeam at its top. A connecting component is fixedly installed between each crossbeam and the top of each central column and side column. Multiple pairs of parallel longitudinal beams are provided in the middle of the top of the crossbeam, and longitudinal beams are provided at both ends of the crossbeam. A template assembly is assembled on the top of the longitudinal beam, and a pair of support beams for supporting the ends of the template assembly are provided at each end of the longitudinal beam.

[0006] Furthermore, the basic structure also includes a steel anchor beam, which is two I-beams. The two I-beams are fixed side by side to the outer wall of the reaction wall of the pedestal, and the steel anchor beam has a through hole for inserting prestressed steel bars at the position of the prestressed steel bar duct of the reaction wall of the pedestal.

[0007] Furthermore, the reaction wall of the platform is provided with several prestressed steel bar ducts for inserting prestressed steel bars.

[0008] Furthermore, the pedestal base, pedestal reaction wall, and pedestal force transmission beam are integrally cast reinforced concrete structures.

[0009] Furthermore, the vertical height of the central column is greater than the vertical height of the side columns.

[0010] Furthermore, both the central column and the side columns are fixedly equipped with anchor plates at their bottoms and fixed plates at their tops. The central column and the side columns are detachably fixedly connected to the pedestal base by high-strength anchor bolts that penetrate the anchor plates.

[0011] Furthermore, each pair of longitudinal beams is respectively located on both sides of each longitudinal rib of the UHPC bridge deck.

[0012] Furthermore, the connecting assembly includes a long threaded bolt, a spring washer, a first nut, a second nut, and a third nut. The lower end of the long threaded bolt is locked to the fixing plate by the first nut, and its upper end is threadedly connected to the second nut. The upper end of the long threaded bolt passes through the lower flange of the crossbeam in sequence and is locked by the third nut. The spring washer is sleeved on the outside of the long threaded bolt and is adapted to be clamped between the bottom of the lower flange of the crossbeam and the second nut.

[0013] Furthermore, the template assembly includes a bottom template, side templates, and end templates. The bottom template is fixedly assembled to the top of the longitudinal beam by spot welding, and its longitudinal ends are correspondingly supported on the top of the support beam. The side templates are correspondingly arranged on the top of the transverse ends of the bottom template, and the end templates are correspondingly arranged on the top of the longitudinal ends of the bottom template. The three work together to form a complete molded cavity for the UHPC bridge deck.

[0014] According to a second aspect of the present invention, a construction method for a precast formwork platform for ribbed prestressed UHPC bridge deck is provided, which is implemented using the aforementioned precast formwork platform for ribbed prestressed UHPC bridge deck, and includes the following steps: S100: First, carry out site leveling, compaction and foundation reinforcement to ensure that the foundation bearing capacity meets the bearing requirements of the formwork platform. After the foundation is accepted, carry out the binding of the foundation steel bars, the erection of the formwork, the pouring of concrete and curing. After completion, the concrete platform is inspected. S200: The steel structure components of the lower support mechanism and the upper support mechanism are processed and manufactured in the factory at the same time. After passing the inspection, they are transported to the site and installed in sequence to form a complete layered support system. S300: Install an attached vibrator on the top of the crossbeam and clean the surface of the bottom formwork to remove impurities and rust. Apply a release agent evenly. Then install the side formwork and end formwork, tie the steel bars of the UHPC bridge deck and insert the prestressed steel bars. At the same time, take measures to prevent grout leakage at the formwork joints, the steel bars on the side formwork and end formwork, and the holes through which the prestressed steel bars pass. S400: Tensioning is performed on the prestressed steel bars that have been installed. After tensioning, the bars are anchored using anchorages. The quality of the steel bar layout, the accuracy of the formwork installation, the measures to prevent grout leakage, and the effect of the prestressing tensioning are then inspected. S500: Use specialized casting equipment to evenly pour UHPC material into the cavity of the template component, start the attached vibrator to perform vibration operation, ensure that the UHPC material is densely filled and free of air bubbles, and take timely measures to cover and moisturize and cure at high temperature after casting to ensure the strength growth and performance stability of UHPC material. S600: After the UHPC strength reaches the design requirements, the side formwork and end formwork are removed in sequence. Special equipment is used to cut the prestressed steel bars for tensioning. Finally, the formed UHPC bridge deck is hoisted off the formwork platform and transported to a designated area for centralized storage.

[0015] In summary, compared with the prior art, the above-described technical solutions conceived by this invention can achieve the following beneficial effects: 1. The present invention provides a ribbed prestressed UHPC bridge deck prefabrication platform. During the UHPC bridge deck forming process, the prestressed steel bars are precisely transferred to the supporting beams at both ends through anchors, and then evenly distributed to the reaction wall of the platform through the supporting beams. The reaction wall then evenly distributes the prestressed steel bars to the platform base and the platform force transmission beam, forming a closed-loop force path. Since the prestress applied by the anchors at both ends is similar in magnitude and opposite in direction, a stable load self-balancing mechanism can be built inside the platform. It does not need to rely on the foundation to bear all the horizontal tension reaction force, which greatly reduces the dependence of the platform on the bearing capacity of the foundation. This allows the platform to adapt to complex geological conditions such as soft soil foundations and backfilled soil foundations, without the need for large-scale foundation reinforcement treatment, and significantly broadens the application scenarios.

[0016] 2. The precast formwork for ribbed prestressed UHPC bridge deck of the present invention utilizes a self-balancing prestressed bearing system in the foundation structure. The formwork does not require the foundation to provide all the horizontal tension reaction force, thereby significantly reducing the construction scale of the foundation engineering. Compared with traditional formwork, this foundation has a smaller excavation volume and a significantly reduced foundation treatment workload. It does not require complex processes such as large-volume concrete pouring or deep pile foundation reinforcement, which not only reduces the material consumption and labor costs of foundation construction, but also simplifies the construction process and shortens the foundation construction cycle.

[0017] 3. The present invention provides a precast formwork platform for ribbed prestressed UHPC bridge deck. The formwork platform adopts a separate layout of lower support mechanism and upper support mechanism, which are connected by a connecting component. The connecting component is an elastic connection system composed of bolts and spring washers, realizing flexible connection between the upper and lower support mechanisms. The stiffness of the connecting system is adjustable. Construction personnel can achieve precise control by adjusting the exposed length of the long screw bolts between the fixed plate and the lower flange of the crossbeam according to the operating parameters of the attached vibrator. This meets the requirements of the flexible superstructure when using the attached vibrator for vibration, ensuring the compactness of UHPC pouring and vibration, giving full play to the high performance advantages of UHPC material. Furthermore, the height of the crossbeam can be adjusted by adjusting the exposed length of the long screw bolts between the fixed plate and the lower flange of the crossbeam, so that all crossbeams are at the same horizontal height.

[0018] 4. This invention provides a precast formwork platform for ribbed prestressed UHPC bridge decks. The ribbed UHPC bridge decks are placed upright on the platform. Distributed channel steel components precisely adapt to the structural requirements of the longitudinal ribs. The channel structure provides stable cavity boundaries for the longitudinal ribs, ensuring dimensional accuracy and appearance quality. Compared to traditional inverted forming methods, this layout eliminates the need for a complex top mold structure, simplifying the overall complexity of the mold system, reducing the difficulty of mold processing, installation, and disassembly, and decreasing material consumption for top mold support components, thus lowering construction costs. More importantly, the upright layout allows air bubbles inside the concrete to rise naturally along the direction of gravity and fully overflow during vibration, effectively reducing defects such as pores and voids inside the components, and improving the density and mechanical properties of the UHPC bridge deck. 5. The present invention provides a precast formwork for a ribbed prestressed UHPC bridge deck. The lower and upper support mechanisms of the formwork adopt a steel structure assembly design. All components are manufactured and processed in a standardized manner, with high dimensional accuracy and strong interchangeability. During construction, the components can be quickly assembled by fasteners such as bolts, without the need for complex welding operations, which greatly shortens the erection and disassembly time of the formwork and improves construction efficiency. Attached Figure Description

[0019] Figure 1This is a schematic diagram of the structure of a precast formwork for a ribbed prestressed UHPC bridge deck according to an embodiment of the present invention. Figure 2 This is a longitudinal mid-section view of a precast formwork for a ribbed prestressed UHPC bridge deck according to an embodiment of the present invention. Figure 3 This is a longitudinal end cross-sectional view of a precast formwork for a ribbed prestressed UHPC bridge deck according to an embodiment of the present invention. Figure 4 This is a transverse mid-section view of a precast formwork for a ribbed prestressed UHPC bridge deck according to an embodiment of the present invention. Figure 5 This is a transverse end cross-sectional view of a precast formwork for a ribbed prestressed UHPC bridge deck according to an embodiment of the present invention. Figure 6 for Figure 2 Partial schematic diagram at point A in the middle; Figure 7 This is a schematic diagram of the foundation structure of a precast formwork platform for a ribbed prestressed UHPC bridge deck according to an embodiment of the present invention. Figure 8 This is a schematic diagram of the lower support mechanism of a precast formwork platform for a ribbed prestressed UHPC bridge deck according to an embodiment of the present invention. Figure 9 This is a schematic diagram of the crossbeam installation of a precast formwork platform for a ribbed prestressed UHPC bridge deck according to an embodiment of the present invention. Figure 10 This is a schematic diagram of the longitudinal beam installation of a precast formwork platform for a ribbed prestressed UHPC bridge deck according to an embodiment of the present invention. Figure 11 This is a schematic diagram of the bottom template of a precast formwork for a ribbed prestressed UHPC bridge deck according to an embodiment of the present invention. Figure 12 This is a schematic diagram of the side template of a precast formwork for a ribbed prestressed UHPC bridge deck according to an embodiment of the present invention. Figure 13 This is a schematic diagram of the end template of a precast formwork for a ribbed prestressed UHPC bridge deck according to an embodiment of the present invention. Figure 14 This is a schematic diagram of the structure of the UHPC bridge panel in an embodiment of the present invention; Figure 15 This is a schematic diagram of the construction method of a precast formwork platform for a ribbed prestressed UHPC bridge deck according to an embodiment of the present invention.

[0020] In all the accompanying drawings, the same reference numerals denote the same technical features, specifically: 1-basin structure, 11-base plate, 12-base reaction wall, 121-prestressed steel reinforcement duct, 13-base force transmission beam, 14-steel anchor beam, 2-lower support mechanism, 21-central column, 22-side column, 23-anchor plate, 24-fixing plate, 3-upper support mechanism, 31-connecting assembly, 311-long threaded bolt, 312-spring washer, 313-first nut, 314-second nut, 315-third nut, 32-crossbeam, 33-longitudinal beam, 34-support beam, 35-template assembly, 351-bottom template, 3511-horizontal section, 3512-bending section, 3513-end crossbeam section, 3514-longitudinal rib groove, 352-side template, 353-end template. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0022] It should be noted that if the embodiments of the present invention involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicators will also change accordingly.

[0023] Furthermore, if the embodiments of this invention involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. If the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0024] In this patent, the terms "comprising," "including," or any other variations thereof are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising..." does not exclude the presence of additional identical elements in the process, method, article, or apparatus that includes said element.

[0025] Example 1 like Figure 1-14 As shown, this embodiment of the invention provides a precast formwork platform for ribbed prestressed UHPC bridge decks, including a foundation structure 1, a lower support mechanism 2, and an upper support mechanism 3. The foundation structure 1 is located on top of the foundation, the lower support mechanism 2 is fixedly installed on top of the foundation structure 1, and the upper support mechanism 3 is fixedly installed on top of the lower support mechanism 2. The three are connected sequentially from top to bottom to form a complete layered formwork platform load-bearing system. The foundation structure 1 serves as the bottom load-bearing foundation of the formwork platform, and its core function is to bear and evenly distribute all the loads from above (including the self-weight of the precast slab, construction loads, and prestressed loads) to the foundation, providing a stable support foundation for the entire formwork platform. The lower support mechanism 2 plays a crucial role in connecting the foundation structure 1 and the upper support mechanism 3, and can be configured according to the precast requirements of ribbed UHPC bridge decks of different specifications. The upper support structure 3 allows for flexible adjustment of the support height and support point distribution, ensuring the installation and positioning accuracy of the upper support structure 3. The upper support structure 3 directly acts on the UHPC bridge deck prefabrication process, providing precise forming support and positioning benchmarks for the ribbed structure of the bridge deck, while also adapting to the load transfer requirements of prestressed concrete construction. The layered structural design clearly defines the functions of each structure, facilitating independent processing, factory prefabrication, and on-site assembly of each component, significantly reducing construction difficulty and on-site work intensity, and shortening the construction cycle. Through the coordinated efforts of the stable bearing capacity of the foundation structure 1, the flexible adaptation of the lower support structure 2, and the precise support of the upper support structure 3, the overall deformation of the formwork during prestressing, concrete pouring, and vibration processes can be effectively controlled, ensuring the stability and accuracy of prestressing application, thereby improving the prefabrication forming accuracy and structural mechanical properties of the ribbed UHPC bridge deck.

[0026] Furthermore, the foundation structure 1 includes a pedestal base 11, a pedestal reaction wall 12, and a pedestal force transmission beam 13. The pedestal base 11 is situated on the foundation, and pedestal reaction walls 12 are integrally formed at the top of both ends along its length. Several prestressed steel bar ducts 121 are drilled through the pedestal reaction walls 12 for inserting prestressed steel bars, providing a path and anchorage support for the prestressed steel bars, and ensuring the stability and reliability of the prestressing process. Pedestal force transmission beams 13 are integrally formed at the top of both ends along the width direction of the pedestal base 11, and the two ends of the pedestal force transmission beams 13 are connected to the foundation foundation. The fixed connection of the pedestal reaction wall 12 can enhance the overall rigidity and deformation resistance of the foundation structure 1. The pedestal base 11, pedestal reaction wall 12 and pedestal force transmission beam 13 form a cavity structure. The lower structure is fixed in the middle of the cavity structure. The pedestal base 11, pedestal reaction wall 12 and pedestal force transmission beam 13 are integrally cast reinforced concrete structures. Compared with prefabricated structures, this can eliminate the stress concentration problem at the joints of components, improve the bearing capacity and durability of the foundation structure 1, and its main stress characteristic is eccentric compression, which provides horizontal reaction force for the pre-tensioned prestressed steel bars.

[0027] Furthermore, the foundation structure 1 also includes a steel anchor beam 14, which consists of two I-beams. The two I-beams are fixed side by side to the outer wall of the reaction wall 12 of the pedestal. The steel anchor beam 14 has a suitable through hole corresponding to the position of the prestressed steel bar channel 121 of the reaction wall 12 of the pedestal. The through hole is used to insert the prestressed steel bar. The steel anchor beam 14 serves as the tensioning anchor end of the prestressed steel bar, used to realize the tensioning positioning and anchoring fixation of the prestressed steel bar.

[0028] Specifically, after the prestressed steel reinforcement tensioning is completed, the resulting tension force is transmitted to the steel anchor beam 14 through the anchorage. The steel anchor beam 14 then evenly distributes the load to the platform reaction wall 12, which in turn transmits it synchronously to the platform base 11 and the platform force transmission beam 13. The platform base 11 and the platform force transmission beam 13 together form a π-shaped cross-section beam structure supported on the foundation. Through the mutual balancing effect of the prestressing forces at both ends, the platform achieves self-balancing bearing capacity as a whole, thereby ensuring the stability and reliability of the prestressing process and reducing dependence on the bearing capacity of the foundation.

[0029] Furthermore, the lower support mechanism 2 includes a central column 21, side columns 22, anchor plates 23, and fixing plates 24. Multiple rows of central columns 21 are arranged along the length of the pedestal base 11 in the cavity structure above the pedestal base 11, and a row of side columns 22 are symmetrically arranged on both sides of the multiple rows of central columns 21, forming a collaborative support system. This ensures that the vertical support force is evenly distributed along the length of the pedestal, avoiding localized stress concentration in the upper structure due to imbalance of support points, and significantly improving the overall load-bearing stability of the lower support mechanism 2. Both the central column 21 and the side columns 22 are made of H-beams. H-beams have high strength and high rigidity, which can provide a stable and reliable load-bearing foundation for the upper support mechanism 3, effectively resisting vertical loads and vibration impacts during construction. Both the central column 21 and the side columns 22 are fixedly fitted with anchor plates 23 at their bottoms and fixed plates 24 at their tops. The anchor plates 23 and fixed plates 24 are integrated and securely connected to the columns through a full welding process, ensuring the force transmission stability and structural integrity of the connection nodes and preventing loosening or displacement during stress. Both the central column 21 and the side columns 22 are detachably fixed to the base 11 by high-strength anchor bolts penetrating the anchor plates 23. The high-strength anchor bolts have excellent tensile and shear resistance, and combined with the surface contact design of the anchor plates 23, they can evenly transmit vertical loads and vibration impact forces, avoiding stress concentration at the connection nodes and ensuring the stability and reliability of the support structure during construction, providing safety for UHPC pouring and vibration. Simultaneously, the detachable design eliminates the need for complex welding, requiring only conventional tools for assembly and disassembly, significantly reducing construction difficulty, shortening the construction period, and facilitating the later transportation, storage, and maintenance of the formwork, reducing disassembly damage, and improving formwork turnover efficiency and service life. The lower support mechanism 2 can provide precise and stable vertical support for the upper support mechanism 3 and the UHPC bridge deck, effectively transferring vertical loads and preventing vertical displacement or uneven deformation of the upper structure during concrete pouring and vibration, thereby ensuring the dimensional accuracy and appearance quality of the UHPC bridge deck.

[0030] Furthermore, the central column 21 is higher than the side columns 22. This height difference design can accurately adapt to the size change of the upper structure, which is "low at both ends and high in the middle". It perfectly matches the construction space requirements of the UHPC bridge deck end beam, avoids support misalignment or uneven force due to the mismatch between the column height and the upper structure, and ensures the fit and stability of the upper support mechanism 3 assembly.

[0031] Furthermore, the upper support mechanism 3 includes a connecting assembly 31, a crossbeam 32, longitudinal beams 33, and a support beam 34. Each row of central columns 21 and side columns 22 has a crossbeam 32 at its top, made of H-beams. A connecting assembly 31 is fixed between each crossbeam 32 and the fixing plate 24 at the top of each central column 21 and side column 22. Multiple pairs of parallel longitudinal beams 33 are provided in the middle of the top of the crossbeam 32, and longitudinal beams 33 are provided at both ends of the crossbeam 32. The longitudinal beams 33 are made of channel steel. The upper flange of the crossbeams 32 is fixedly connected to the lower flange of the longitudinal beams 33 by bolts. Each pair of longitudinal beams 33 is arranged on both sides of each longitudinal rib of the UHPC bridge deck. The top of the longitudinal beams 33 is equipped with a template assembly 35. The longitudinal beams 33 can precisely adapt to the longitudinal rib structure of the UHPC bridge deck. Through targeted support on both sides of the longitudinal ribs of the precast slab, multi-point uniform load-bearing of the UHPC bridge deck is achieved, avoiding the problem of uneven support points during the forming or stressing of the precast slab. Reasonable local stress concentration ensures the forming quality of the precast slab. Simultaneously, the channel steel longitudinal beams 33 possess both lightweight and high bending stiffness characteristics, which can improve vertical bearing capacity and deformation resistance while reducing the self-weight of the superstructure 3, thus reducing the impact of the support system's own deformation on the forming accuracy of the precast slab. Each end of the longitudinal beams 33 is provided with a pair of support beams 34, made of channel steel, used to support the formwork assembly 35. The support beams 34 have through holes corresponding to the positions of the prestressed steel reinforcement ducts 121 for inserting prestressed steel reinforcement. The installation of these support beams 34 effectively widens the support surface of the formwork assembly 35, evenly transferring the UHPC pouring load and construction load borne by the formwork assembly 35 to the longitudinal beams 33 and transverse beams 32. This prevents the formwork assembly 35 from warping, deforming, or breaking due to localized overload, ensuring the support stability and stiffness of the formwork system, and thus ensuring the forming dimensional accuracy of the UHPC bridge deck.

[0032] Specifically, the longitudinal beam 33 consists of three sections: an end longitudinal beam, an oblique longitudinal beam, and a middle longitudinal beam. The two ends of the middle longitudinal beam are fixedly connected to a downwardly inclined oblique longitudinal beam, and the other end of the oblique longitudinal beam is fixedly connected to the end longitudinal beam, so that the entire longitudinal beam forms a continuous zigzag beam that matches the bottom shape of the precast slab.

[0033] Furthermore, the connecting assembly 31 includes a long threaded bolt 311, a spring washer 312, a first nut 313, a second nut 314, and a third nut 315. The lower end of the long threaded bolt 311 is locked to the fixing plate 24 by the first nut 313, and its upper end is threadedly connected to the second nut 314. The upper end of the long threaded bolt 311 passes through the lower flange of the crossbeam 32 and is locked by the third nut 315. The spring washer 312 is sleeved on the outside of the long threaded bolt 311 and is adapted to be clamped at the bottom of the lower flange of the crossbeam 32 and the second nut 315. Between 14, a bolt + spring washer elastic connection system is formed to realize the elastic connection between the crossbeam 32 and the lower support mechanism 2. The connection stiffness of this elastic connection system can be flexibly adjusted. The crossbeam 32 and the lower support mechanism 2 have good independence. By adjusting the locking degree of the second nut 314 and the third nut 315 and the compression amount of the spring washer 312, the stiffness requirements of the flexible upper structure during the operation of the attached vibrator can be accurately matched, ensuring that the upper structure achieves overall uniform vibration, effectively avoiding local over-vibration problems, and thus meeting the compaction requirements of UHPC pouring vibration.

[0034] Specifically, the stiffness of the connecting component 31 can be precisely controlled by adjusting the exposed length of the long bolts 311 between the fixing plate 24 and the lower flange of the crossbeam 32, to adapt to the stiffness requirements of the flexible upper support mechanism 3 during the vibration operation of the attached vibrator. By tightening the second nut 313 and the third nut 315, the locking distance of the long bolts 311 between the fixing plate 24 and the lower flange of the crossbeam 32 is adjusted, thereby changing the effective force-bearing length of the long bolts 311 between the fixing plate 24 and the lower flange of the crossbeam 32. This is coordinated with the degree of compression deformation of the spring washer 312 to achieve flexible adjustment of the overall stiffness of the connecting component 31. At the same time, during the assembly of the crossbeam 32, the vertical height of the crossbeam 32 can be adjusted by adjusting the exposed length of the long bolts 311 between the fixing plate 24 and the lower flange of the crossbeam 32, so that the height of all the crossbeams 32 is within the same plane.

[0035] Furthermore, the template assembly 35 includes a bottom template 351, side templates 352, and end templates 353. The bottom template 351 is fixedly assembled to the top of the longitudinal beam 33 by spot welding, and its two longitudinal ends are correspondingly supported on the top of the support beam 34. With the cooperative support of the longitudinal beam and the support beam, the load-bearing stability and surface flatness of the bottom template 351 can be effectively guaranteed, providing a solid foundation for the bottom surface forming of the UHPC bridge deck. The side templates 352 are correspondingly arranged on the top of the transverse ends of the bottom template 351, and the end templates 353 are correspondingly arranged on the top of the longitudinal ends of the bottom template 351. The three work together to form a complete forming cavity for the UHPC bridge deck, ensuring the integrity of the component forming.

[0036] Furthermore, the bottom template 351 includes a horizontal portion 3511, a bent portion 3512, an end crossbeam portion 3513, and longitudinal rib grooves 3514. The two ends of the horizontal portion 3511 are fixedly connected to the downwardly extending bent portion 3512. The end of the bent portion 3512 away from the horizontal portion 3511 is integrally formed with the end crossbeam portion 3513. The end crossbeam portion 3513 is recessed inward to form a groove. This groove is used to precisely adapt to the structural shape of the end crossbeam of the UHPC bridge deck, ensuring the forming accuracy and appearance quality of the end crossbeam. The horizontal portion 3511 of the bottom template 351 is provided with several longitudinal rib grooves 3514 spaced apart in the transverse direction. The longitudinal rib grooves 3514 and the grooves of the end crossbeam portion 3513 are interconnected, ensuring that the longitudinal ribs and end crossbeams of the UHPC bridge deck can be integrally formed, improving the continuity and mechanical performance of the overall structure of the component.

[0037] Furthermore, the outer wall of the end beam portion 3513 of the bottom formwork 351 is provided with prestressed steel bar ducts for threading pre-tensioned prestressed steel bars.

[0038] Furthermore, the side formwork 352 has an L-shaped structure, including a horizontal plate and a vertical plate. The longitudinal contour of the horizontal plate is adapted to the longitudinal shape of the bottom formwork 351, forming a tightly fitting lateral support structure with the bottom formwork 351. This effectively resists the lateral pressure generated during UHPC pouring and prevents grout leakage. The horizontal plate has downwardly extending side formwork bending portions on both sides. The other end of the side formwork bending portion has a side formwork end beam portion. The side formwork end beam portion is recessed downward to form a side formwork groove, which matches the groove of the end beam portion 3513. Multiple stiffening ribs are fixedly installed on the outer walls of the horizontal and vertical plates of the side formwork 352 at intervals. Through the strengthening effect of the stiffening ribs, the overall rigidity of the side formwork 352 can be significantly improved, avoiding excessive deformation due to stress that could affect the dimensional accuracy of the UHPC bridge deck. The stiffening ribs also have openings, providing convenient conditions for demolding operations and reducing the difficulty of demolding and the risk of component damage.

[0039] Furthermore, the end template 353 is a stepped plate, whose structural shape can precisely match the construction of the UHPC bridge deck end, ensuring the integrity and stress coordination of the overall structure of the UHPC bridge deck. At the bottom step of the outer wall of the stepped plate of the end template 353, multiple stiffening ribs are fixedly installed at intervals. These stiffening ribs can effectively improve the rigidity and deformation resistance of the end template 353, preventing excessive deformation during construction, thereby ensuring the forming accuracy of the UHPC bridge deck end. At the same time, the openings on the stiffening ribs can further optimize the convenience of demolding operations.

[0040] To ensure the connection strength of the wet joints in the UHPC bridge deck, the reinforcing bars on the sides and ends need to extend outwards to form anchoring reinforcement for the wet joint. Therefore, corresponding slots for reinforcing bars are provided on the side formwork 352 and the end formwork 353 to ensure that the anchoring reinforcement can pass through smoothly. In addition, to facilitate the processing, manufacturing, disassembly, and subsequent maintenance of the formwork, both the side formwork 352 and the bottom formwork 351 are divided into several independent units along the length direction, which can realize modular design and improve the versatility and turnover efficiency of the formwork.

[0041] Furthermore, the corresponding rebar opening slots on the side template 352 and end template 353 are precisely matched with the wet joint anchoring rebars extending outward from the side and end faces of the UHPC bridge deck. During installation, after the anchoring rebars are passed through the corresponding rebar opening slots, the anchoring rebars are fixed to the side template 352 and end template 353 by locking devices (such as buckles and binding wires).

[0042] Example 2 Combination Figure 1-14 ,like Figure 15 As shown, this invention provides a construction method for a precast formwork platform for ribbed prestressed UHPC bridge decks, which is implemented using the aforementioned ribbed prestressed UHPC bridge deck precast formwork platform. The specific steps are as follows: S100: First, carry out site leveling, compaction and foundation reinforcement to ensure that the foundation bearing capacity meets the bearing requirements of the formwork platform. After the foundation is accepted, carry out the binding of steel bars, erection of formwork, pouring of concrete and curing of foundation structure 1. After completion, the concrete platform is inspected. S200: The steel structure components of the lower support mechanism 2 and the upper support mechanism 3 are processed and manufactured simultaneously in the factory. After passing the inspection, they are transported to the site and installed in sequence to form a complete layered support system. S300: Install an attached vibrator on the top of the crossbeam 32, clean the surface of the bottom formwork 351 to remove impurities and rust, and apply a release agent evenly. Then install the side formwork 352 and the end formwork 353, tie the steel bars of the UHPC bridge deck and insert the prestressed steel bars. At the same time, take measures to prevent grout leakage at the formwork joints, the steel bars on the side formwork 352 and the end formwork 353, and the holes through which the prestressed steel bars pass. S400: Tensioning is performed on the prestressed steel bars that have been installed. After tensioning, the bars are anchored using anchorages. The quality of the steel bar layout, the accuracy of the formwork installation, the measures to prevent grout leakage, and the effect of the prestressing tensioning are then inspected. S500: Use a special casting equipment to evenly cast the UHPC material into the cavity of the template component 35, start the attached vibrator to perform vibration operation, ensure that the UHPC material is densely filled and free of air bubbles, and take timely measures to cover and moisturize and cure at high temperature after casting to ensure the strength growth and performance stability of the UHPC material. Specifically, after the UHPC material is poured, vibrated, and leveled, a film is first applied to the surface of the component for moisture retention and curing, followed by the erection of a steam curing shed for high-temperature steam curing. The steam curing shed is a rectangular structure, with its edges supported by the reaction wall 12 of the pedestal and the force transmission beam 13 around it. Together with the foundation structure, it forms a sealed steam curing space, which can effectively ensure the stability of the temperature and humidity of the steam curing environment, achieve uniform steam curing of the UHPC component throughout, ensure that the steam curing is sufficient and thorough, help the UHPC material quickly reach the design strength, and at the same time ensure that its mechanical properties and durability meet the standards.

[0043] S600: After the UHPC strength reaches the design requirements, the side formwork 352 and end formwork 353 are removed in sequence. Special equipment is used to cut the prestressed steel bars for tensioning. Finally, the formed UHPC bridge deck is hoisted off the formwork platform and transported to a designated area for centralized storage.

[0044] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A precast formwork for ribbed prestressed UHPC bridge deck, characterized in that, It includes the basic structure (1), the lower support structure (2), and the upper support structure (3); among which, The basic structure (1) includes a pedestal base (11), a pedestal reaction wall (12), and a pedestal force transmission beam (13). The pedestal base (11) is set on the foundation. The pedestal reaction wall (12) is integrally set at the top of both ends along the length direction. The pedestal force transmission beam (13) is integrally set at the top of both ends along the width direction of the pedestal base (11). The two ends of the pedestal force transmission beam (13) are fixedly connected to the pedestal reaction wall (12). The pedestal base (11), the pedestal reaction wall (12), and the pedestal force transmission beam (13) together form a cavity structure. The lower support mechanism (2) is fixedly installed on the top of the foundation structure (1), which includes a central column (21) and side columns (22). Multiple rows of central columns (21) are provided in the cavity structure above the pedestal base (11) along the length direction of the pedestal base (11), and a row of side columns (22) are symmetrically arranged on both sides of the multiple rows of central columns (21) to form a cooperative support system. The upper support mechanism (3) is fixedly installed on the top of the lower support mechanism (2). It includes a connecting component (31), a crossbeam (32), a longitudinal beam (33), a support beam (34), and a template component (35). Each row of central columns (21) and side columns (22) is provided with a crossbeam (32) at the top. Each crossbeam (32) is fixedly connected to the top of each central column (21) and side column (22) with a connecting component (31). The top of the crossbeam (32) is provided with multiple pairs of parallel longitudinal beams (33), and the two ends of the crossbeam (32) are provided with longitudinal beams (33). The top of the longitudinal beam (33) is equipped with a template component (35). Each end of the longitudinal beam (33) is provided with a pair of support beams (34) for supporting the ends of the template component (35).

2. The precast formwork for a ribbed prestressed UHPC bridge deck according to claim 1, characterized in that, The basic structure (1) also includes a steel anchor beam (14), which is two I-beams. The two I-beams are fixed side by side on the outer wall of the platform reaction wall (12), and the steel anchor beam (14) has a through hole for inserting prestressed steel bars at the position corresponding to the prestressed steel bar duct (121) of the platform reaction wall (12).

3. The precast formwork for a ribbed prestressed UHPC bridge deck according to claim 2, characterized in that, The platform reaction wall (12) is provided with several prestressed steel bar ducts (121) for inserting prestressed steel bars.

4. The precast formwork for a ribbed prestressed UHPC bridge deck according to claim 2, characterized in that, The pedestal base (11), pedestal reaction wall (12) and pedestal force transmission beam (13) are integrally cast reinforced concrete structures.

5. The precast formwork for a ribbed prestressed UHPC bridge deck according to claim 1, characterized in that, The vertical height of the central column (21) is greater than the vertical height of the side column (22).

6. A precast formwork for a ribbed prestressed UHPC bridge deck according to claim 5, characterized in that, The bottom of the central column (21) and the side column (22) are both fixedly equipped with anchor plates (23), and the top of both are fixedly equipped with fixing plates (24). The central column (21) and the side column (22) are detachably fixedly connected to the base plate (11) by high-strength anchor bolts penetrating the anchor plates (23).

7. The precast formwork for a ribbed prestressed UHPC bridge deck according to claim 1, characterized in that, Each pair of longitudinal beams (33) is located on both sides of each longitudinal rib of the UHPC bridge deck.

8. The precast formwork for a ribbed prestressed UHPC bridge deck according to claim 1, characterized in that, The connecting assembly (31) includes a long screw bolt (311), a spring washer (312), a first nut (313), a second nut (314), and a third nut (315). The lower end of the long screw bolt (311) is locked to the fixing plate (24) by the first nut (313), and the upper end of the long screw bolt (311) is threadedly connected to the second nut (314). The upper end of the long screw bolt (311) passes through the lower flange of the crossbeam (32) and is locked by the third nut (315). The spring washer (312) is sleeved on the outside of the long screw bolt (311) and is adapted to be clamped between the bottom of the lower flange of the crossbeam (32) and the second nut (314).

9. A precast formwork for a ribbed prestressed UHPC bridge deck according to claim 1, characterized in that, The template assembly (35) includes a bottom template (351), side templates (352) and end templates (353). The bottom template (351) is fixedly assembled to the top of the longitudinal beam (33) by spot welding, and its two longitudinal ends are supported on the top of the support beam (34). The side templates (352) are arranged on the top of the two transverse ends of the bottom template (351), and the end templates (353) are arranged on the top of the two longitudinal ends of the bottom template (351). The three work together to form a complete molded cavity for the UHPC bridge deck.

10. A construction method for a precast formwork platform for ribbed prestressed UHPC bridge deck, characterized in that, The method employs a ribbed prestressed UHPC bridge deck prefabrication formwork as described in any one of claims 1-9, characterized by comprising the following steps: S100: First, carry out site leveling, compaction and foundation reinforcement to ensure that the foundation bearing capacity meets the bearing requirements of the formwork platform. After the foundation is accepted, carry out the binding of steel bars, setting up of formwork, pouring of concrete and curing of the foundation structure (1). After completion, the concrete platform is inspected. S200: The steel structure components of the lower support mechanism (2) and the upper support mechanism (3) are processed and manufactured in the factory at the same time. After passing the inspection, they are transported to the site and installed in sequence to form a complete layered support system. S300: Install an attached vibrator on the top of the crossbeam (32), clean the surface of the bottom formwork (351), remove impurities and rust, apply release agent evenly, then install the side formwork (352) and end formwork (353), tie the steel bars of the UHPC bridge deck and insert the prestressed steel bars, and at the same time take measures to prevent grout leakage at the formwork joints, the steel bars on the side formwork (352) and end formwork (353) and the holes through which the prestressed steel bars pass; S400: Tensioning is performed on the prestressed steel bars that have been installed. After tensioning, the bars are anchored using anchorages. The quality of the steel bar layout, the accuracy of the formwork installation, the measures to prevent grout leakage, and the effect of the prestressing tensioning are then inspected. S500: Use special casting equipment to uniformly cast UHPC material into the cavity of the template component (35), start the attached vibrator to perform vibration operation, ensure that the UHPC material is densely filled and free of air bubbles, and take timely measures to cover and moisturize and high temperature curing after casting to ensure the strength growth and performance stability of UHPC material. S600: After the UHPC strength reaches the design requirements, the side formwork (352) and end formwork (353) are removed in sequence. Special equipment is used to cut the prestressed steel bars for tensioning. Finally, the formed UHPC bridge deck is hoisted out of the formwork platform and transported to a designated area for centralized storage.

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