UHPC prefabricated slab, composite beam and construction method thereof

Abstract

The application relates to a UHPC prefabricated plate, which comprises a first embedded component enclosed by a plurality of steel plates; a plurality of groups of second embedded components are arranged in parallel along the longitudinal bridge direction, each group of the second embedded components comprises a plurality of T-shaped pieces arranged at intervals along the transverse bridge direction, the upper flange surface of the T-shaped piece is flush with the upper surface of the steel plate; a shear key is vertically arranged on the upper surface of the steel plate and the T-shaped piece; a UHPC pouring layer is formed on the upper surfaces of the first embedded component and the second embedded component, and the horizontal projection of the UHPC pouring layer is located in the range covered by the first embedded component; the UHPC pouring layer is provided with reserved notches between the adjacent T-shaped pieces in the transverse bridge direction, and at least one row of the reserved notches is arranged along the longitudinal bridge direction center line. The adopted UHPC significantly reduces the thickness of the prefabricated plate, reduces the material consumption, reduces the hoisting weight, solves the problem that it is difficult to manufacture the reinforced concrete prefabricated plate and to hoist the oversized prefabricated plate at low cost, and reduces the construction difficulty.

Description

Technical Field

[0001] This application relates to the field of bridge structure technology, and in particular to a UHPC precast slab, a composite beam, and a construction method thereof. Background Technology

[0002] Steel-concrete composite beams combine the high strength, good ductility and easy processing of steel with the high compressive strength of concrete, giving full play to the advantages of the two materials. The overall performance is significantly better than the simple superposition of the two properties, and has a high economic and technical advantage. However, the ordinary concrete used in traditional composite beams has the following problems: (1) low tensile strength, easy cracking, large creep and heavy self-weight; (2) concrete bridge deck is prone to cracking in the negative bending moment zone, which leads to steel corrosion and water seepage. It is a weak link in the durability of composite beams and one of the key factors that limit its application to larger spans. Frequent maintenance is not only costly, but also affects traffic; (3) in order to meet the strength and stiffness requirements, ordinary concrete bridge decks are usually thick, resulting in a large self-weight of the structure, which limits the span capacity and increases the burden on the substructure and foundation; (4) under harsh conditions such as de-icing salt and marine environment, the deterioration rate of ordinary concrete bridge decks is faster, which affects the service life of the structure.

[0003] Ultra-high performance concrete (UHPC) possesses ultra-high strength, ultra-high durability, excellent crack resistance, and high toughness. When combined with steel beams, it forms UHPC slab composite beams, aiming to overcome the limitations of traditional steel-concrete composite beams. In current technical solutions, UHPC slabs are prefabricated in a factory, studs are pre-welded to the steel beams, the prefabricated slabs are transported to the site and aligned with the steel beams during hoisting, and the UHPC is cast in place at the joints. This structural form requires high-quality in-place casting of the joints to achieve the bonding between the UHPC slabs and the steel beams, and the transportation of large-sized prefabricated components is limited. Summary of the Invention

[0004] This application provides a UHPC precast slab, a composite beam, and a construction method thereof to solve the problems in related technologies, such as the inconvenience of pre-welding studs on steel beams and the in-situ casting of UHPC at joints, and the low bonding strength.

[0005] In a first aspect, a UHPC prefabricated board is provided, comprising:

[0006] The first embedded component is enclosed by multiple steel plates;

[0007] The second embedded component has multiple sets arranged parallel to the longitudinal direction of the bridge. Each set of the second embedded component includes multiple T-shaped pieces arranged at intervals along the transverse direction of the bridge. The upper flange surface of the T-shaped piece is flush with the upper surface of the steel plate.

[0008] Shear keys are vertically disposed on the upper surfaces of the steel plate and the T-shaped member;

[0009] The UHPC casting layer is cast onto the upper surface of the first and second embedded components, and its horizontal projection is located within the area covered by the first embedded component.

[0010] The UHPC casting layer has reserved slots between adjacent T-shaped members in the transverse direction, and at least one row of the reserved slots is set along the longitudinal centerline.

[0011] In some embodiments, the drainage assembly includes multiple drainage channels arranged along the transverse direction of the bridge, with the T-shaped members fixedly connected to both ends along the longitudinal direction of the bridge, and the top of the drainage channel spaced apart from the T-shaped members. Multiple support members are provided on the drainage channels along the longitudinal direction of the bridge, and each support member is arranged parallel to the transverse direction of the bridge.

[0012] In some embodiments, the support members arranged along the transverse bridge direction are inclined with the center of the UHPC precast slab being lower in the middle and higher on both sides.

[0013] In some embodiments, the center distance between adjacent shear keys is 1 to 2 times their own length.

[0014] In some embodiments, the diameter of the shear key on the T-shaped part of the second embedded component is larger than the diameter of the shear key on the steel plate of the first embedded component.

[0015] In some embodiments, the first embedded component and the second embedded component are symmetrically arranged along the transverse and longitudinal directions of the bridge.

[0016] In some embodiments, the edges of the UHPC casting layer are provided with tongue and groove joints.

[0017] Secondly, a UHPC precast slab composite beam is provided, comprising:

[0018] steel beams;

[0019] Multiple UHPC precast panels are disposed on the steel beam, and the bottoms of the first and second embedded components of the UHPC precast panels are welded to the steel beam.

[0020] Factory wet joints are cast and molded between the first embedded components of adjacent UHPC precast slabs.

[0021] Thirdly, a construction method for UHPC precast slab composite beams is provided, including the following steps:

[0022] Install the first embedded component, the second embedded component, and the drainage component; tie the steel mesh and tension it for fixation.

[0023] UHPC is poured to form precast slabs, which are then vibrated, leveled, and cured.

[0024] The cured UHPC precast slabs are hoisted onto the steel beams, and the first and second embedded components are welded to the steel beams.

[0025] Factory wet joints are poured between adjacent precast slabs to complete beam segment assembly.

[0026] Fourthly, a bridge is provided, comprising: a UHPC precast slab composite beam prepared using the construction method described above; and transverse on-site wet joints cast between beam segments.

[0027] This application provides a UHPC precast slab, which significantly reduces the thickness of the precast slab, decreases material usage, and lightens the lifting weight. It solves the problem of manufacturing and low-cost lifting of ultra-large precast slabs made of reinforced concrete, thus reducing construction difficulty. Due to its dense material properties and structural design, this structure significantly reduces the size of the reserved slots for shear keys, optimizes shear connections, and reduces the workload of casting. Through the UHPC casting template, the first and second embedded components are solidified by the UHPC. Because shear keys are set on the upper surfaces of the first and second embedded components, a strong interlocking force is formed with the UHPC casting layer, ensuring coordinated stress distribution between the embedded components and the UHPC, improving the bending and shear resistance and overall stiffness of the precast slab. Simultaneously, during the UHPC casting and high-temperature curing stages, the bonding and mechanical interlocking between the shear keys and the UHPC effectively constrains and internally absorbs the shrinkage deformation of the UHPC, thereby significantly reducing... The reduced shrinkage stress transmitted to the steel beams prevents bridge deck cracking at its source. The main stress path is shifted from the concrete wet joints to the embedded components, reducing the width of the longitudinal and transverse wet joints in the precast slabs. The connection of the reinforcing bars in the wet joints is simplified from traditional bending and welding to a lap-only design, resolving the problem of reinforcing bar conflicts during construction, reducing reinforcing bar length, saving material usage, and lowering construction difficulty and cost. Pre-reserved slots along the longitudinal direction are set between adjacent T-shaped components in the transverse direction, facilitating subsequent connection to the steel beams via centralized shear keys. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 This is a schematic diagram of the UHPC prefabricated panel structure provided in the embodiments of this application;

[0030] Figure 2 This is a schematic diagram of the transverse cross-section of a UHPC precast slab provided in an embodiment of this application;

[0031] Figure 3 This is a schematic diagram of the longitudinal section of a UHPC precast slab provided in an embodiment of this application;

[0032] Figure 4 for Figure 1 Enlarged view of a portion of point A in the middle;

[0033] Figure 5 for Figure 1 A partially enlarged schematic diagram of the drainage channel at point B;

[0034] Figure 6 A schematic diagram of the shear key arrangement of the UHPC precast slab provided in the embodiments of this application;

[0035] Figure 7 A schematic diagram of the transverse section of the shear key arrangement of the UHPC precast slab provided in the embodiments of this application;

[0036] Figure 8 for Figure 6 Enlarged view of a portion of point C in the middle;

[0037] Figure 9 for Figure 6 Enlarged view of a portion of point D;

[0038] Figure 10 This is a schematic diagram showing the end state of step 1 of the construction method according to an embodiment of the present invention;

[0039] Figure 11 This is a schematic diagram showing the end state of step 2 of the construction method according to an embodiment of the present invention;

[0040] Figure 12 This is a schematic diagram showing the end state of step 3 of the construction method according to an embodiment of the present invention;

[0041] Figure 13 This is a schematic diagram showing the end state of step 4 of the construction method in an embodiment of the present invention.

[0042] In the diagram: 100, UHPC precast slab; 1, first embedded component; 101, steel plate; 2, second embedded component; 201, T-shaped component; 3, UHPC casting layer; 4, shear key; 5, reserved groove; 6, drainage component; 601, drainage channel; 602, support component; 7, tongue and groove joint; 8, centralized shear key; 200, steel beam; 300, factory wet joint; 400, construction site wet joint. Detailed Implementation

[0043] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0044] This application provides a UHPC precast slab that solves the problems of inconvenient construction and low bonding strength in related technologies, such as pre-welding studs on steel beams and casting UHPC at joints.

[0045] like Figures 1 to 9 As shown, a UHPC prefabricated panel includes:

[0046] The first pre-embedded component 1 is surrounded by multiple steel plates 101. It is pre-embedded in advance when the UHPC precast slab is poured, forming the bottom mold of the wet joint between the precast slab and the adjacent precast slab. The upper surface of the steel plate 101 is provided with multiple vertically arranged shear keys 4.

[0047] The second embedded component 2 is arranged in parallel along the longitudinal direction of the bridge. Each set of the second embedded component 2 includes multiple T-shaped parts 201 arranged at intervals along the transverse direction of the bridge. They are pre-embedded when the UHPC precast slab is poured. The upper flange surface of the T-shaped part 201 is flush with the upper surface of the steel plate 101. Multiple vertically arranged shear keys 4 are provided on its upper surface.

[0048] UHPC casting layer 3 is cast into the upper surface of the first embedded component 1 and the second embedded component 2, and its horizontal projection is located within the area covered by the first embedded component 1.

[0049] The UHPC casting layer 3 has reserved slots 5 between adjacent T-shaped members 201 in the transverse direction, and at least one row of reserved slots 5 is set along the longitudinal centerline of the bridge to facilitate subsequent connection with the steel beam 200 through centralized shear keys 8.

[0050] Figure 1 In the middle, the arrow points in the transverse direction of the bridge. This application provides a UHPC precast slab. Through the UHPC casting template, the UHPC solidifies the first embedded component 1 and the second embedded component 2. Since shear keys 4 are set on the upper surfaces of the first embedded component 1 and the second embedded component 2, they form a strong interlocking force with the UHPC casting layer 3, ensuring that the embedded components and the UHPC share the load, improving the bending and shear resistance and overall stiffness of the precast slab. The size of the precast slab can reach 15.8m × 6.4m, achieving a larger span and higher load-bearing capacity under the same size, breaking through the size and performance limitations of conventional UHPC precast slabs caused by insufficient connection strength.

[0051] Meanwhile, during the UHPC casting and high-temperature curing stages, the bonding and mechanical interlocking between the shear key 4 and the UHPC effectively constrained and internally absorbed the shrinkage deformation of the UHPC, thereby significantly reducing the shrinkage stress transmitted to the steel beam 200 and preventing the bridge deck from cracking at its source.

[0052] The main stress path is shifted from the concrete wet joint to the embedded components, reducing the width of the longitudinal and transverse wet joints of the precast slab. The connection of the steel bars in the wet joint is simplified from the traditional bending and welding to a lap-only design, which solves the problem of steel bar conflict during construction, reduces the length of steel bars, saves material usage, and reduces construction difficulty and cost.

[0053] Furthermore, it also includes:

[0054] The drainage assembly 6 includes multiple drainage channels 601 arranged along the transverse direction of the bridge, T-shaped members 201 fixedly connected to both ends of the drainage channel 601 along the longitudinal direction of the bridge, and the top of the drainage channel 601 is spaced apart from the T-shaped members 201. Multiple support members 602 arranged along the longitudinal direction of the bridge are provided on the drainage channel 601, and each support member 602 is arranged parallel to the transverse direction of the bridge.

[0055] Furthermore, the support members 602 arranged along the transverse bridge direction are inclined with the center of the UHPC precast slab being lower in the middle and higher on both sides.

[0056] To prevent excessive temperature differences between the top and bottom of the precast slabs when using industrial electric heating blankets for heat curing of wet joints in the factory, this solution includes a drainage and support system. Specifically, such as... Figure 1 and Figure 2 As shown, U-shaped channel steel is welded between adjacent T-shaped components in the longitudinal direction of the bridge to serve as a drainage trough. The top of the drainage trough is spaced apart from the T-shaped components. Holes are opened in the U-shaped channel steel for the support members 602 to pass through and fix them. The support members 602 are iron pipes. Multiple support members 602 set on the drainage trough 601 are used to support industrial electric heating blankets. The condensation generated during the curing process collects on the electric heating blankets. Through the inclined support members 602, the water vapor on the electric heating blankets is discharged into the steel beam box along the drainage trough 601, thereby avoiding the impact of residual water vapor on the structural durability.

[0057] Furthermore, the distance between adjacent shear keys 4 is 1 to 2 times the length of the shear key 4.

[0058] In this embodiment, the shear key 4 is a stud. In some alternative embodiments, the shear key 4 is an angle steel or a channel steel.

[0059] In conventional concrete composite structures, to prevent splitting failure of coarse aggregate concrete under shear key action, the spacing of shear keys typically needs to be no less than three times their length. This invention utilizes the characteristics of UHPC material—uniform texture, absence of coarse aggregate, and ultra-high tensile strength and toughness—to achieve a dense arrangement of shear keys by reducing the spacing to approximately the same as their length, for example, one time the key length. This not only significantly improves the shear connection strength and structural stiffness at the interface but also further optimizes the shrinkage stress distribution of UHPC through more uniform force flow.

[0060] Furthermore, the diameter of the shear key 4 provided on the T-shaped part 201 of the second embedded component 2 is larger than the diameter of the shear key 4 provided on the steel plate 101 of the first embedded component 1.

[0061] The first embedded component 1 is mainly used for the bottom formwork and surrounding connections of the wet joint, while the second embedded component 2 undertakes more of the force transmission task of the main structure. Setting a larger diameter shear key 4 can enhance the shear resistance and connection strength of this area, ensuring that the force can be more effectively transferred to the steel beam under load, thereby improving the overall stiffness and load-bearing capacity of the structure. By setting the diameter of the shear key differently, the functional positioning of each embedded component can be better matched, achieving efficient use of materials.

[0062] Furthermore, the first embedded component 1 and the second embedded component 2 are symmetrically arranged along the transverse and longitudinal directions of the bridge. This ensures uniform stress distribution of the UHPC precast slab in the plane, avoids local stress concentration caused by asymmetrical component arrangement, and reduces the risk of cracking and deformation of the precast slab during load-bearing. At the same time, the symmetrical structure ensures that the stress state of each connection point is consistent when the precast slab is combined with the steel beam, ensuring the overall stress coordination of the composite beam, reducing the additional burden on the steel beam or precast slab caused by stress imbalance, and improving the overall stability and durability of the structure.

[0063] Furthermore, the edge of the UHPC casting layer 3 is provided with a tongue and groove joint 7.

[0064] To enhance the connection strength of the joints, rectangular tongue and groove joints 7 are provided on the bridge deck at wet joints. The standard tongue and groove joint height is 0.25m, the width is 0.4m, and the standard tongue and groove joint center-to-center distance is 0.8m.

[0065] This application provides a UHPC precast slab composite beam, which includes:

[0066] 200 steel beams;

[0067] Multiple UHPC precast slabs 100 are set on the steel beam 200, and the bottoms of the first embedded component 1 and the second embedded component 2 of the UHPC precast slab 100 are welded to the steel beam 200.

[0068] The factory wet joint 300 is cast and molded between the first embedded component 1 of the adjacent UHPC precast slab 100.

[0069] like Figures 10 to 13 As shown in this application, a single beam segment consists of four UHPC precast slabs 100, forming three longitudinal wet joints and three transverse wet joints. The three longitudinal wet joints are all factory wet joints 300, with the two side longitudinal wet joints 300 being 1.3m wide and the middle longitudinal wet joint 300 being 0.9m wide. The three transverse wet joints include one factory transverse wet joint and two on-site cast-in-place transverse wet joints. The factory transverse wet joint is 0.6m wide, and the transverse on-site cast-in-place wet joint 400 is 0.6m wide.

[0070] The precast slab size can reach 15.8m × 6.4m, with a rectangular tongue-and-groove joint (7). Reinforcing bars must cross the tongue-and-groove joint. The flatness of the precast slab is ±1.5mm. Temporary fastening devices are installed to prevent interference with T-shaped components 201 and embedded steel plates 101 during UHPC construction. The anchorage length of the intersecting reinforcing bars in the bridge deck after passing the intersection point must be greater than 12d. The main reinforcement bars of adjacent precast slabs within the joint are connected by lap splicing, with a lap length of not less than 40cm.

[0071] T-shaped component 201 is pre-embedded as an embedded part during the casting of UHPC precast slabs. Simultaneously, embedded steel plates 101 are also installed around the perimeter of the precast slabs, serving as the bottom formwork for factory wet joints 300 and on-site wet joints 400. The thickness of steel plates 101 and T-shaped components is 12mm. After the precast slab 100 is fabricated, it is hoisted and placed on the steel beam 200. Welds are then welded between the embedded steel plates 101, T-shaped components 201, and the steel beam 200. The factory wet joint 300 is then cast on the formwork, forming a complete composite beam segment. The on-site wet joint 400 between beam segments needs to be cast on-site at the bridge site.

[0072] A drainage channel 601 is arranged under the UHPC precast slab 100 and fixed together with the T-shaped piece 201. The drainage channel 601 has a support member 602.

[0073] The reserved slot 6 corresponds to the position of the centralized shear key 14 on the steel beam 200, with a size of 400×550mm. The spacing of the centralized shear key 8 is 100mm.

[0074] In this embodiment, the distributed shear key 4 uses studs with a diameter of 22mm and a length of 100mm, which are evenly arranged on the top plate of the T-shaped part 201 at a spacing of 200mm.

[0075] In this embodiment, the distributed shear key 4 uses studs with a diameter of 19mm and a length of 100mm, which are evenly arranged on the top plate of the pre-embedded steel plate 101 set in the transverse direction at a spacing of 175mm along the longitudinal direction and 200mm along the transverse direction.

[0076] In this embodiment, the distributed shear key 4 uses studs with a diameter of 19mm and a length of 150mm, which are evenly arranged on the top plate of the pre-embedded steel plate 101 set in the longitudinal direction at a spacing of 200mm along the longitudinal direction and 225mm along the transverse direction.

[0077] like Figures 10 to 13 As shown in the figure, this application embodiment provides a construction method for UHPC precast slab composite beams, which includes the following steps:

[0078] S1: Install the first embedded component 1, the second embedded component 2, and the drainage component, and tie and tension the steel mesh.

[0079] Specifically, install T-shaped parts 201 and steel plates 101, and weld drainage grooves 601 onto T-shaped parts 201. A 5mm gap is designed between each embedded part, which is sealed with tape from the top to prevent grout leakage. Small gaps between the embedded parts and the mold are sealed with silicone sealant. A rectangular groove core mold is installed on the edge of the precast slab, fixed in position by positioning pins on the edge mold, quickly installed and positioned, and tightened with bolts. After mold assembly, the mold surface is ground to remove rust and evenly coated with release agent. Edge positioning tension plates are set around the bottom mold for fixing and pre-tensioning the reinforcing bars. Under the premise of deformation less than 2mm, the long side of the tension plate can withstand a tensile force of 2±0.5kN per reinforcing bar, and the short side can withstand a tensile force of 4±0.5kN per reinforcing bar. Two layers of reinforcing mesh are tied, and the ends of the reinforcing bars in the mesh are fixed to the edge positioning tension plates and tensioned.

[0080] S2: Pour UHPC to form precast slabs, and then vibrate, level and cure them.

[0081] Specifically, before placing the concrete, the reinforcing bars and formwork should be sprayed with water to moisten them, ensuring there is no standing water. During the placement process, the ultrasonic humidifiers on both sides of the formwork should be turned on to maintain the humidity of the pouring area and prevent the UHPC from crusting in hot weather. The UHPC placing machine spans across the top of the formwork, placing the concrete in 80cm units longitudinally.

[0082] UHPC (Ultra-High-Pressure Compaction) compaction is performed using attached vibrators and an array of inserted vibrating rods mounted on the mold platform. A total of 44 attached vibrators are arranged at the bottom of the mold platform, with a transverse spacing of 1.6m. Vibration parameters are set to 12kN-150Hz, and the compaction time is 60s. After the vibrating rod reaches a frequency of 200Hz, it is inserted as quickly as possible to a distance of 1.5cm from the bottom mold, vibrated for 8s, and then withdrawn for 7s. The vibrating machine trolley then moves forward to the next compaction position, and the compaction action is repeated.

[0083] After vibration, the leveling and covering machine is turned on, using a high-frequency vibratory pusher plate for excitation. The excitation frequency is 3500 rpm, and the excitation force is 20 kN. Before leveling, the vibrator is kept in close contact with the side mold, and the UHPC thickness is controlled by the ultrasonic system to ensure that the pusher plate contacts the concrete surface so that the vibration waves can effectively level the concrete. During construction, the vibration mode is turned on and the machine is moved forward slowly at a speed of about 4 m / min. One worker is assigned to use a vibratory leveling tool to finish and level the surface of the surrounding groove area.

[0084] After the UHPC is leveled and finished, an automatic film and fabric covering machine is used to cover the UHPC with film and fabric.

[0085] After demolding, the UHPC precast panels are transferred to the steam curing area for high-temperature steam curing.

[0086] S3: Hoist the cured UHPC precast slab 100 onto the steel beam 200, and weld the first embedded component 1 and the second embedded component 2 to the steel beam 200.

[0087] The UHPC precast slab 100 was roughened on all four sides using a high-pressure water jet device. The roughening depth was 5-10mm, and the roughening was done to expose the steel fibers across the entire cross-section. Then, the UHPC precast slab 100 was hoisted and placed at the corresponding positions on the flange of the web of the steel beam 200, and the welds between the embedded steel plate 101, the T-shaped component 201, and the steel beam 200 were welded.

[0088] S4: Cast wet joints between adjacent precast slabs in the factory to complete the beam segment assembly.

[0089] Specifically, after the UHPC precast slab 100 is placed, the factory wet joint 300 is poured and subjected to moisture retention and high-temperature steam curing. An industrial electric heating blanket is placed at the bottom of the factory wet joint 300 via the support 602 of the drainage trough 601 to assist in heating and curing, preventing excessive temperature differences between the top and bottom. The drainage trough 601 simultaneously drains the water generated during curing from the steel beam 200 box, preventing residual moisture inside the steel beam 200 box from affecting structural durability.

[0090] The beneficial effects of the technical solution provided in this application include:

[0091] 1) The present invention provides a composite beam structure for ultra-large UHPC slabs based on distributed and clustered combined shear keys. Compared with conventional reinforced concrete composite beam structures, the UHPC used in this invention significantly reduces the thickness of the precast slabs, reduces the amount of materials used, and reduces the lifting weight. It solves the problem of difficult manufacturing of reinforced concrete precast slabs and low-cost lifting of ultra-large precast slabs, and reduces the difficulty of construction.

[0092] 2) The present invention provides a composite beam structure for ultra-large UHPC slabs based on distributed and clustered combined shear keys. Compared with conventional reinforced concrete composite beam structures, this structure significantly reduces the size of the reserved slots for shear keys due to its dense material properties and structural design, optimizes shear connections, and reduces the workload of its casting construction.

[0093] 3) The present invention provides a composite beam structure for ultra-large UHPC slabs based on distributed and clustered combined shear keys, which reduces the width of the longitudinal and transverse wet joints of the precast slabs, simplifies the connection of the reinforcing bars in the wet joints from the traditional bending and welding to a lap-only design, solves the problem of reinforcing bar conflict during construction, reduces the length of reinforcing bars, saves material usage, and greatly reduces construction difficulty and construction cost.

[0094] 4) The present invention provides a composite beam structure for ultra-large UHPC slabs based on distributed and clustered combined shear keys. This structure improves the installation accuracy of UHPC slabs, reduces welding processes, improves the performance and durability of composite beams, and realizes the manufacturing of ultra-large UHPC precast slabs by using pre-embedded steel beam diaphragm top plate T-shaped parts and pre-embedded steel plates around the precast slabs.

[0095] 5) The present invention provides a composite beam structure for ultra-large UHPC slabs based on distributed and clustered combined shear keys. The structure has distributed shear keys on the T-shaped embedded parts of the transverse diaphragms and the embedded steel plates. During the UHPC casting and curing stages, the influence of shrinkage can be eliminated to the greatest extent, shrinkage stress can be reduced, and cracking can be avoided.

[0096] 6) The present invention provides a composite beam structure for ultra-large UHPC slabs based on distributed and clustered combined shear keys. The ultra-large UHPC precast slabs in this structure are prefabricated in a standardized manner in the factory using precast templates and then transported to the site for construction. This results in higher quality, excellent mechanical properties, avoidance of early cracking caused by cast-in-place UHPC bridge decks, higher efficiency, and greater market potential.

[0097] In the description of this application, it should be noted that the terms "upper," "lower," etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Unless otherwise expressly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two elements. For those skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances.

[0098] It should be noted that in this application, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover 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 limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0099] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A UHPC prefabricated panel, characterized in that, It includes: The first embedded component (1) is enclosed by multiple steel plates (101); The second embedded component (2) is arranged in parallel along the longitudinal direction of the bridge. Each set of the second embedded component (2) includes multiple T-shaped parts (201) arranged at intervals along the transverse direction of the bridge. The upper flange surface of the T-shaped part (201) is flush with the upper surface of the steel plate (101). Shear key (4) is vertically disposed on the upper surface of the steel plate (101) and the T-shaped piece (201); UHPC casting layer (3) is cast into the upper surface of the first embedded component (1) and the second embedded component (2), and its horizontal projection is located within the area covered by the first embedded component (1). The UHPC casting layer (3) has reserved slots (5) between adjacent T-shaped members (201) in the transverse direction, and at least one row of the reserved slots (5) is set along the longitudinal direction centerline; The drainage assembly (6) includes multiple drainage channels (601) arranged along the transverse bridge direction, with the T-shaped member (201) fixedly connected to both ends along the longitudinal bridge direction, and the top of the T-shaped member (201) spaced apart from the top of the drainage channel (601). Multiple support members (602) arranged along the longitudinal bridge direction are provided on the drainage channel (601), and each support member (602) is arranged parallel to the transverse bridge direction. Each support member (602) arranged along the transverse bridge direction is inclined with the center of the UHPC precast slab as the reference, and the middle is lower and the sides are higher.

2. The UHPC prefabricated panel as described in claim 1, characterized in that: The center distance between adjacent shear keys (4) is 1 to 2 times their own length.

3. The UHPC prefabricated panel as described in claim 1, characterized in that: The diameter of the shear key (4) set on the T-shaped part (201) of the second pre-embedded component (2) is larger than the diameter of the shear key (4) set on the steel plate (101) of the first pre-embedded component (1).

4. The UHPC prefabricated panel as described in claim 1, characterized in that: The first embedded component (1) and the second embedded component (2) are symmetrically arranged along the transverse and longitudinal directions of the bridge.

5. The UHPC prefabricated panel as described in claim 1, characterized in that: The edge of the UHPC casting layer (3) is provided with a tongue and groove joint (7).

6. A UHPC precast slab composite beam, characterized in that, It includes: Steel beam (200); Multiple UHPC precast slabs (100) as described in any one of claims 1 to 5 are disposed on the steel beam (200), and the bottoms of the first embedded component (1) and the second embedded component (2) of the UHPC precast slab (100) are welded to the steel beam (200); Factory wet joint (300) is cast between the first embedded component (1) of the adjacent UHPC precast slab (100).

7. A construction method for a UHPC precast slab composite beam, used for the construction of the UHPC precast slab composite beam as described in claim 6, characterized in that, Includes the following steps: Install the first embedded component (1), the second embedded component (2), and the drainage component (6), and tie and tension the steel mesh; UHPC is poured to form precast slabs, which are then vibrated, leveled, and cured. The cured UHPC precast slab (100) is hoisted onto the steel beam (200), and the first embedded component (1) and the second embedded component (2) are welded to the steel beam (200); Factory wet joints are poured between adjacent precast slabs to complete beam segment assembly.

8. A bridge, characterized in that, include: UHPC precast slab composite beams prepared using the construction method described in claim 7; And the transverse wet joints (400) cast between beam segments.

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