Detachable beam plate type supporting-bearing UHPC (Ultra High Performance Concrete) blanket structure system and mounting method

Abstract

The invention discloses a detachable beam plate type supporting-bearing UHPC blanket structure system and an installation method. The detachable beam plate type supporting-bearing UHPC blanket structure system and the installation method are used for improving detachable installation. The system comprises a top beam, a bracket, a detachable profile steel externally-wrapped UHPC prefabricated beam arranged above a bracket structure, a cross brace and a UHPC prefabricated bridge deck slab structure located on the prefabricated beam. A beam-top beam wet connection structure, a beam-plate shear connector and a plate-plate bolt assembly structure are adopted. A first support of the foundation pit is replaced by the precast beam, a wet connection structure between the precast beam and the top beam achieves a supporting effect, and the precast bridge deck is laid above the precast beam to provide passage and achieve a bearing effect. And the force transmission effect of the first support is enhanced, and the horizontal load and the vertical bearing capacity are effectively borne. The purpose that the prefabricated bridge deck slab and the prefabricated beam are detachable is achieved through bolt connection of the beam-slab shear-resistant connecting piece and the UHPC prefabricated bridge deck slab.

Description

Technical Field

[0001] The invention relates to a detachable beam-slab support-bearing UHPC blanket structure system and an installation method, belonging to the technical field of subway foundation pit construction. Background Art

[0002] With the increasing pace of urbanization, the effective use of underground space has become a key strategy to alleviate urban traffic congestion and improve the overall efficiency of the transportation system. In this context, the quality and efficiency of underground engineering construction are particularly critical, and the design and implementation of the first support structure are the most important. This structure is not only the cornerstone to ensure the stability and safety of the project, but also directly related to the economy and timeliness of the construction. Traditionally, the first support mainly adopts cast-in-place concrete technology. Although this structure can withstand axial tension and pressure, it cannot effectively cope with vertical loads, which limits the possibility of laying the upper prefabricated bridge deck. In addition, the cast-in-place method not only requires a long period of maintenance, which prolongs the construction period, but also does not have the characteristics of being detachable, resulting in a large consumption of resources and costs.

[0003] During the excavation of the foundation pit, the protection of the surrounding environment and traffic management pose severe challenges. The long-term construction site fencing and the long construction period have a significant impact on the flow of surrounding traffic. Especially when multiple subway foundation pits are under construction at the same time, this impact will be magnified to the entire city level, seriously restricting the smooth operation of urban traffic. The existing foundation pit paving mostly adopts cast-in-place technology, which also faces the problem of long maintenance cycle. In addition, it is limited to construction personnel in the construction area and cannot meet the daily traffic needs of the public.

[0004] Therefore, it is necessary to develop an innovative subway foundation pit covering structure system and its rapid construction and installation technology. The system needs to have an integrated "support-bearing" function, which can not only serve as a stable first support to withstand complex stresses, but also directly lay prefabricated bridge panels on top to bear the loads of vehicles and pedestrians to ensure the normal operation of ground traffic. On this basis, the introduction of ultra-high performance concrete (UHPC) materials aims to break through the limitations of existing technologies through its high strength, high toughness and high durability, and achieve a perfect integration of support structure functions and traffic bearing capacity, while significantly shortening construction time and reducing interference with urban traffic. Summary of the invention

[0005] Purpose of the invention: The purpose of the present invention is to provide a detachable beam-slab support-bearing UHPC blanket structure system and installation method, through beam-crown beam, beam-slab, and plate-slab connections, to complete a foundation pit blanket structure system that can be disassembled, opened and closed, and can be recycled, thereby minimizing the impact of foundation pit construction on the public's daily traffic and solving the drawbacks of the existing blanket structure system.

[0006] The technical solution adopted by the present invention to solve the technical problem is: A detachable beam-slab support-bearing UHPC blanket structure system, which adopts a structural system of UHPC prefabricated beams, prefabricated bridge decks and crown beams wrapped with steel sections, and is characterized by: The main body of the steel-wrapped UHPC prefabricated beam is a composite structural beam with internal steel and external UHPC shell, and beam end steel plates are arranged at both ends of the steel-wrapped UHPC prefabricated beam, and there is an upwardly extending plug-in on the steel-wrapped UHPC prefabricated beam; The prefabricated bridge deck comprises a prefabricated bridge deck body and a socket, wherein the socket is embedded in the prefabricated bridge deck as an embedded part, and two adjacent prefabricated bridge decks are fastened and connected by a splicing seam connection section; The steel-wrapped UHPC prefabricated beam and the crown beam are in a wet connection structure, and a corbel is provided on the crown beam corresponding to the wet connection structure. Rubber bearings are provided between the two ends of the steel-wrapped UHPC prefabricated beam and the corbels for transition support. The wet connection structure includes a beam end steel plate, a tension screw, a crown beam embedded steel plate, anchor steel bars and poured concrete, wherein the anchor steel bars are welded to the back of the crown beam embedded steel plate and embedded in the crown beam, and the beam end steel plate is welded to the steel-wrapped beam in the prefabricated beam; one end of the tension screw is mechanically connected to the beam end steel plate, and the other end is welded to the crown beam embedded steel plate, and the poured concrete is filled in the space between the beam end steel plate and the crown beam embedded steel plate; The plug-in connector and the socket connector are embedded and connected by interlocking in the form of male and female grooves.

[0007] A pair of ear walls are arranged on the corbel, and the ear walls constrain the ends of the steel-wrapped UHPC prefabricated beams and both sides of the wet connection structure.

[0008] The high-strength bolts welded on the upper part of the plug-in component, bolt holes are reserved on the top of the socket component, two layers of anchor steel bars are welded on the outside, and the high-strength bolts pass through the bolt holes and are fastened by nuts.

[0009] The connector and the socket are both cylindrical steel components, and both are steel shell structures.

[0010] The inner diameter of the socket is slightly larger than the outer diameter of the connector by 1 mm to 2 mm, the diameter of the bolt hole is slightly larger than the diameter of the high-strength bolt by 1 mm, and the high-strength bolt is embedded in the bolt hole.

[0011] The edge of the joint connection section is configured as a serrated edge, and the two prefabricated bridge panels are mechanically engaged with each other via the serrated connection section.

[0012] Two adjacent steel-wrapped UHPC prefabricated beams are mechanically connected by cross braces or scissor braces.

[0013] Studs are welded at the web of the inner steel section of the steel section enclosing the UHPC prefabricated beam to form a shear key, and anchor holes are arranged at the web, and the anchor holes avoid the two ends of the steel section and the position with the maximum bending moment.

[0014] A method for installing a detachable beam-slab support-bearing UHPC blanket structure comprises the following steps: S1: Forming of UHPC prefabricated beams wrapped with steel: Processing I-shaped steel, welding shear keys on the web of the steel, forming anchor holes by laser cutting at locations avoiding shearing and maximum bending moments, welding beam end steel plates on both ends of the steel, and then mechanically connecting the tension screws to the beam end steel plates through matching nuts; Process the connector and weld the anchor steel bars outside the connector. After completion, weld the connector to the upper wing plate of the steel section according to the position set in the drawing; Processing cross braces; Customize the casting mold for UHPC precast beams wrapped with steel according to the design drawings, place the processed steel at the predetermined position in the mold, fix it with a positioning fixture, cast UHPC, and remove the mold after high-temperature steam curing for 24 hours. Then, static curing is performed to obtain the UHPC precast beams wrapped with steel; S2: Forming of prefabricated bridge deck: according to the design drawings, the template is processed and the prefabricated bridge deck is cast and formed. The end of the prefabricated bridge deck has a tongue and groove and high-strength bolts are pre-embedded. The splicing seam connection section is prefabricated or machine-formed. Bolt sleeves are pre-embedded on the splicing seam connection section. The prefabricated bridge deck and the splicing seam connection section are obtained through curing and are ready for use; S3: Forming of ground-connected walls, crown beams and corbels: According to the design drawings, dig the soil layer at the crown beam and corbel setting point, set up the concrete formwork, then install the steel cage, and pre-embed the crown beam pre-embedded steel plate and anchor steel bars. At the same time, cast the ground-connected walls, crown beams and corbels. After curing, remove the formwork, set rubber bearings above the corbels, and set ear walls. S4: Transportation and hoisting: Use hoisting equipment to hoist the steel-wrapped UHPC precast beams and precast bridge decks to the area to be supported in the foundation pit. During hoisting, adjust the angle and state of the steel-wrapped UHPC precast beams so that the bottom of the beams are located directly above the bridge bearings, and then slowly drop them to place the ends of the steel-wrapped UHPC precast beams in the middle of the ear walls. After hoisting in place, measure the verticality between the steel-wrapped UHPC precast beams and the ground-connected walls on both sides. Select a fixed point on the ground-connected wall as the measurement reference point and install the total station. Align the total station with the reference point and perform initial settings. Use the laser ranging and angle measurement functions of the total station to measure multiple points on both sides of the steel-wrapped UHPC precast beams and the ground-connected wall, directly read and record the verticality data, and adjust the verticality between the steel-wrapped UHPC precast beams and the ground-connected wall based on the measurement results. Finally, weld the tension bolts to the crown beam embedded steel plate for temporary fixation. S5: Forming of crown beam and wet connection: Before pouring, fully check the stability of the support system, confirm that all connection parts are stable and reliable, ensure the effective connection between the tension screws at both ends of the steel-wrapped UHPC prefabricated beam and the welded steel plate, the crown beam embedded steel plate, and the stability of the steel-wrapped UHPC prefabricated beam and the rubber bearing bolts; According to the design drawings, the casting formwork for the crown beam and wet connection position is erected, the upper formwork is placed on the upper part of the embedded steel plate of the crown beam, and the bottom formwork is set above the corbel. Then the steel cage inside the crown beam is installed, and the ordinary concrete of the crown beam and wet connection is poured at the same time. After curing, the formwork is removed; S6: Cross brace, beam-slab, and slab-slab connection: After the wet connection construction is completed, the cross brace is lifted by a gantry and moved to the precast beam. After fine adjustment, it is fixed with high-strength bolts. After the cross brace connection is completed, the precast bridge deck is lifted by a gantry and moved above the steel-wrapped UHPC precast beam. The angle and state of the precast bridge deck are adjusted so that the socket is located directly above the connector in the precast beam, and then slowly dropped, the connector is engaged with the socket and fixed with nuts, and then the two precast bridge decks are connected using the splicing seam connection section and fixed with nuts.

[0015] After step S6, a dismantling step S7 is also included: dismantling the prefabricated bridge deck: dismantling the bolts step by step from the periphery to the center, and dismantling the bolts connecting adjacent UHPC prefabricated bridge decks; after the high-strength bolts connecting the prefabricated bridge decks are dismantled, the high-strength bolts on the connectors are dismantled using the same method, and after ensuring that all the connecting bolts are loosened, the prefabricated bridge deck is lifted by a gantry, and the prefabricated bridge deck is slowly pulled out of the connector, slowly lifted out of the original position, avoiding obstacles, and smoothly transferred to a designated storage or recycling area; S8: Dismantling precast beams: Use a vibrating chisel to open the wet connection. For the remaining concrete on the outside of the beam end steel plate, use a cutting machine to cut it off to ensure the integrity of the beam end steel plate. Then unscrew the nuts to remove the bolts of the tension screws and rubber bearings, so that the entire steel-wrapped UHPC precast beam is separated and slowly lifted away, avoiding obstacles, and smoothly transferred to the designated storage or recycling area.

[0016] The beneficial effects of the present invention are: (1) The beam-crown beam wet connection form of the present invention realizes the detachable connection of the first prefabricated beam, and the connector realizes the detachable connection of the beam and the slab, so that the structure can be easily disassembled and reinstalled after the construction is completed, realizing recycling, greatly improving the convenience of maintenance and reducing the long-term operation and maintenance costs, and is easier to promote and apply in practical applications.

[0017] (2) The composite I-beam structure formed by combining steel sections with UHPC materials significantly improves the compressive, tensile and bending properties, thereby enhancing the bearing capacity and stability of the overall structure, providing excellent bearing capacity and stability guarantees for the overall engineering structure, enabling it to easily cope with heavier loads and more complex mechanical environments, and demonstrating excellent adaptability to extreme conditions.

[0018] (3) The wet connection technology adopted by the present invention ensures that the connection structure remains unchanged while bearing the huge load from above, accurately fixes the beam-slab connection point, and ensures the structural integrity and safety and stability of the first support. In addition, the excellent resistance of this connection method to axial tension and compression further strengthens the safety line of the support system.

[0019] (4) The present invention efficiently lays prefabricated bridge panels on prefabricated beams through prefabricated construction. In turn, the prefabricated bridge panels can form a three-dimensional system with prefabricated beams and crown beams, that is, a stable and efficient closed traffic system is constructed within the limited foundation pit construction space, effectively reducing the area occupied by the construction on the surrounding road surface and maintaining the necessary traffic flow. This strategy greatly alleviates the urban traffic pressure during the construction period and the impact on residents' daily commuting.

[0020] (5) The present invention greatly simplifies the construction process and improves construction efficiency through fully prefabricated assembled components, while ensuring high standards of construction quality. It perfectly adapts to the stringent requirements of modern underground engineering projects for rapid construction and safety standards, and leads the trend of innovation in construction technology. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 It is a schematic diagram of the overall construction effect of the present invention.

[0022] Figure 2 It is a schematic diagram of the structure of the steel-wrapped UHPC prefabricated beam of the present invention.

[0023] Figure 3 Detailed schematic diagram of the wet connection structure of the present invention.

[0024] Figure 4 It is a schematic diagram of the wet connection completion structure of the present invention.

[0025] Figure 5 It is a detailed schematic diagram of the steel section welded connector of the present invention.

[0026] Figure 6 Schematic diagram of the shear connector of the present invention.

[0027] Figure 7 It is a schematic diagram of the socket-and-plug connection of the present invention.

[0028] Figure 8 It is a schematic diagram of bolt connection of the prefabricated bridge deck of the present invention.

[0029] Fig. 9 It is a schematic diagram of the connection between the cross brace and the steel section of the present invention.

[0030] In the figure: 100 steel-clad UHPC prefabricated beams, 110 steel, 111 shear key, 112 anchor hole, 120 UHPC shell, 130 Wet connection structure, 131 Beam end steel plate, 132 Tension screw, 133 Crown beam embedded steel plate, 134 Anchor steel bar, 135 Wet connection concrete 140 connector, 141 high-strength bolt, 142 anchor steel bar, 150 cross brace, 151 cross brace connecting steel plate, 152 bolt, 200 UHPC precast bridge deck, 210 prefabricated bridge deck body, 220 socket, 221 bolt hole, 230 joint connection section, 231 upper connection section, 232 lower connection section, 233 high-strength bolt, 234 bolt sleeve, 300 crown beam, 310 corbel, 320 rubber bearing, 330 ear wall, 340 ground-connected wall. DETAILED DESCRIPTION

[0031] This embodiment introduces a detachable beam-slab support-bearing UHPC paving structure system and installation method. The main structure of the system adopts a construction system composed of prefabricated beams and prefabricated bridge panels. These components are all industrial prefabricated components, which are prefabricated and formed in a prefabrication factory, and have the advantages of high standardization and high surface forming quality. The formed components are transported, hoisted, and wet-connected for rapid operation, meeting the requirements of prefabricated construction.

[0032] In the following embodiments, the directional noun longitudinal refers to the length direction of the support, also called the axial direction, represented by the X-axis, and the lateral refers to the length direction of the crown beam, represented by the Y-axis.

[0033] Embodiment 1 In order to make the objectives, technical solutions and advantages of the present invention more clear, the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0034] like Figures 1 to 9As shown, a detachable beam-slab support-bearing UHPC blanket structure system and installation method are provided, wherein the structure system realizes the detachability of the steel-UHPC I-beam precast beam and the crown beam structure through a modular connection device, realizes the detachability between the precast beam and the UHPC board through connectors welded on the steel, and realizes the detachable support and bearing integrated UHPC blanket structure system of the blanket system through bolt connection between the blanket boards.

[0035] The inner core of a steel-wrapped UHPC prefabricated beam 100 is a steel 110, which is preferably an I-beam. The UHPC shell 120 is wrapped and covered on the outside of the steel, and the UHPC shell 120 forms an increased cross-sectional area of ​​the steel-wrapped UHPC prefabricated beam 100 on the cross section, thereby improving the anti-overturning performance of the steel-wrapped UHPC prefabricated beam 100.

[0036] Furthermore, the steel in the steel-encased UHPC precast beam is an I-beam, which has the advantages of torsion resistance and bending resistance, and has sufficient strength and rigidity to withstand axial tension and pressure, as well as the traffic load on the precast bridge deck after laying. Under the action of bending load, the steel-encased UHPC precast beam structure can give full play to the excellent high strength and high toughness characteristics of UHPC materials, promote the synergistic working effect of steel and UHPC materials, and significantly enhance the bending bearing capacity of the precast beam. In the design, the I-shaped section is preferred as the profile of the support beam. This is based on its inherent advantages in resisting torsion and bending, and can show higher structural strength with the same amount of material used. Under other design requirements, the I-beam can also be replaced by steel with other sections.

[0037] Furthermore, the above-mentioned steel-wrapped UHPC precast beams replace the role of the first support, play the integrated function of "support-bearing", and bear the axial tension and pressure while assuming the bearing capacity of the traffic above.

[0038] Furthermore, the bottom plate of the steel section 110 is located at the bottom of the UHPC, that is, the entire steel section is wrapped around the bottom of the UHPC prefabricated beam, which can better play a bending-resistant role when subjected to upper loads.

[0039] Furthermore, the above-mentioned steel-wrapped UHPC prefabricated beam is provided with steel-wrapped 110 inside, and longitudinal reinforcement and steel cage are no longer required, and the end beam end steel plate and the steel-wrapped bottom plate can be used as casting templates, saving materials. And the section of the prefabricated beam formed after the UHPC is also an I-shaped section.

[0040] Further, refer to Figure 2 Studs are welded at the web of the steel section 110 to form a shear key 111, and anchor holes 112 are set at the web. The studs and anchor holes are mainly used to enhance the bonding between the steel section and UHPC.

[0041] Furthermore, no anchor holes are provided at the places where the steel 110 is subjected to shear (the two ends of the steel) and where the bending moment is the largest (the middle section of the steel), that is, the anchor holes avoid the places where the bending moment is the largest, so as to meet the load-bearing requirements and prevent structural damage.

[0042] The two ends of the above-mentioned steel-clad UHPC prefabricated beam and the crown beam are connected by a wet connection structure.

[0043] Furthermore, the wet connection structure 130 as a whole includes a beam end steel plate 131, a tension screw 132, a crown beam embedded steel plate 133, anchoring steel bars 134 and poured concrete 135. Among them, the anchoring steel bar 134 is welded to the back of the crown beam embedded steel plate to form a whole and is embedded in the crown beam 300, and is in a state to be connected. At the same time, the beam end steel plate 131 is welded to both ends of the prefabricated beam medium steel 110, that is, it is fixed to both ends of the prefabricated beam, and a threaded hole is drilled and threaded on the beam end steel plate 131. During installation, one end of the tension screw 132 is mechanically connected to the beam end steel plate 131, and the other end passes through the crown beam embedded steel plate and is welded at the node to achieve the preliminary mechanical fixation of the above-mentioned prefabricated beam.

[0044] After the precast beam is hoisted, the crown beam and the wet connection formwork are supported, and concrete is poured at the same time. When the concrete solidifies, a rigid fixed connection is formed between the end of the precast beam and the crown beam 300. This cast-in-place construction method is called wet connection, and this rigid connection structure is defined as a wet connection structure. When the wet connection structure is subjected to axial tension, it can be transmitted to the tension screw 132 through the crown beam embedded steel plate 133 pre-embedded in the crown beam, and then transmitted to the beam end steel plate 131, and finally the axial tension is borne by the steel section; when the wet connection structure is subjected to axial pressure, it is directly transmitted to the precast beam section by the poured concrete, and finally the axial pressure is borne by the entire section of the UHPC shell.

[0045] Furthermore, the thickness of the beam end steel plate 131 is about three times that of the crown beam embedded steel plate 133, so as to prevent the tensioning screw from transmitting the tension force and causing the steel plate to deform.

[0046] Furthermore, the size of the crown beam embedded steel plate 133 is slightly smaller than the beam end steel plate to prevent the crown beam embedded steel plate from being exposed after pouring wet connection concrete. At the same time, the upper template for pouring concrete can be assumed to be on the upper part of the crown beam embedded steel plate.

[0047] Furthermore, after the lifting is completed, the positions of the tension bolts and the beam end steel plates are adjusted, and the outer ends of the tension bolts are made to abut against the embedded steel plates of the crown beams through adjustment. The tension screws are welded to the embedded steel plates of the crown beams to prevent the tension screws from changing due to the shrinkage creep of the concrete, thereby ensuring that the position of the tension screws is fixed.

[0048] refer to Fig. 9A cross brace is preset on the above-mentioned steel-wrapped UHPC prefabricated beam, and the cross brace is welded and fixed to the web of the I-beam and exposed. Every two steel-wrapped UHPC prefabricated beams 100 are mechanically connected to the cross braces on the prefabricated beams on both sides through a cross brace 150. The cross brace is a small-sized I-beam. Connecting ends are set at both ends of the cross brace, which are mechanically connected to the cross brace through high-strength bolts, which is also a detachable cross brace connection form.

[0049] Furthermore, for connecting two steel-wrapped UHPC prefabricated beams, either a transverse brace or a scissors brace can be used.

[0050] Furthermore, the cross brace 150 is composed of two sections and is connected by externally provided steel plates 151 and fixed by bolts 152. Through this structure, the length of the cross brace can be adjusted to adapt to the construction of steel-encased UHPC prefabricated beams with different spacings, thereby realizing customized installation.

[0051] Furthermore, the cross brace 150 can evenly distribute the load to the nearby steel-wrapped UHPC prefabricated beams, thereby enhancing the lateral force resistance and overall stability of the structure and preventing damage to the supporting structure caused by excessive load concentration.

[0052] Furthermore, the bottom of the connector 140 is welded above the upper wing plate of the steel section, and a high-strength bolt 141 is welded above the connector to fix it when connected to the prefabricated bridge deck. Anchor steel bars 142 are welded outside to enhance the anchoring force and bonding force with the UHPC.

[0053] A UHPC prefabricated bridge deck 200 is structurally divided into a prefabricated bridge deck body 210, a socket 220, and a splicing seam connection section 230 at both ends. The bridge deck body 210 is prefabricated with steel bars and UHPC and has specific technical parameters.

[0054] Furthermore, a bolt hole 221 is reserved at the top of the socket 220, and two layers of anchoring steel bars 142 are welded on the outside to enhance the bonding strength with the UHPC in the prefabricated bridge deck.

[0055] Furthermore, both the connector and the socket are cylindrical steel components, both are steel shell structures, and they are basically the same in appearance, except for the size of the circle diameter. The outer diameter of the connector is similar to the inner diameter of the socket, and there is no filling material inside, so that the two can be interlocked and connected in a parent-child groove form.

[0056] Furthermore, the socket is embedded in the prefabricated bridge deck as an embedded part, and is precisely aligned with the connector welded on the steel section when the beam and the slab are connected. The two are embedded and connected in the form of a mother-and-child groove, and at the same time, through fine adjustment, the high-strength bolts welded on the upper part of the connector pass through the bolt holes reserved on the upper part of the socket, and then the nut is installed to complete the assembly of the beam-slab connector.

[0057] Furthermore, taking into account the human errors, environmental errors and random errors of construction workers during construction, the inner diameter of the above-mentioned socket is slightly larger than the outer diameter of the connector by 1-2mm, and the diameter of the bolt hole is slightly larger than the diameter of the high-strength bolt by 1mm, that is, when the beam-slab is plug-in connected, it can be ensured that the connector can be inserted into the socket, and the high-strength bolt can be fitted into the bolt hole by slightly adjusting the inside.

[0058] Further, refer to Figure 8 The joint connection sections at both ends adopt an overlapping assembly structure. Connection sections 230 are respectively arranged at both ends of the two prefabricated bridge panels. The high-strength bolts 233 embedded in the lower connection section 232 and the bolt sleeves 234 embedded in the upper connection section 231 can be accurately fitted together to complete the assembly. Furthermore, in order to enhance the mechanical properties of the connection portion, the edge of the connection section may be set to a serrated edge, and the two prefabricated bridge panels are mechanically engaged with each other through the serrated connection section, thereby increasing the stability of the overall connection structure.

[0059] A crown beam 300, which can be a reinforced concrete crown beam or a steel structure crown beam. In this embodiment, the description is based on a reinforced concrete crown beam. The construction process and technical points of the crown beam are as follows: The crown beam 300 is provided with a corbel 310 , which may be continuous in the horizontal direction or segmented in the horizontal direction, and functions to provide a support point for the first support beam.

[0060] Furthermore, a rubber bearing 320 is provided on the above-mentioned corbel 310 to ensure that the position of the steel-wrapped UHPC prefabricated beam on the corbel is stable. Through the provision of the rubber bearing, the vertical load and horizontal load borne can be effectively transferred to the corbel, ensuring the overall stability and safety; the rubber bearing has good elasticity and adaptability, and can adapt to the expansion and contraction deformation of the steel-wrapped UHPC prefabricated beam under the influence of environmental factors such as temperature and humidity, as well as the deformation caused by other loads, thereby extending the service life of the support.

[0061] Furthermore, a pair of ear walls 330 are provided on the above-mentioned corbel 310, and the ear walls constrain the ends of the steel-wrapped UHPC prefabricated beams and both sides of the wet connection structure to improve the lateral stability thereof.

[0062] Furthermore, the ear wall 330 can also be arranged on the crown beam, that is, on the crown beams on both sides of the wet connection structure, which can also serve the purpose of constraining the steel-wrapped UHPC prefabricated beam and both sides of the wet connection structure.

[0063] Furthermore, the cap beam is constructed above the ground-connected wall 340 , and the cap beam and the wet connection structure are cast simultaneously after the ground-connected wall and the corbel construction are completed.

[0064] The above-mentioned beam-crown beam wet connection method has a positive significance in the installation stage. It is to ensure the tight installation of the support and the crown beams on both sides. After installation, the support can transmit the axial tension to the steel section through the connection between the end tension screws and the steel plate, so that the steel part in the steel-wrapped UHPC precast beam bears the tension, and the pressure is transmitted through the concrete at the wet connection part, so that the UHPC part in the steel-wrapped UHPC precast beam bears the pressure, which optimizes the force structure and ensures stable force transmission.

[0065] During the construction of the wet connection structure, the steel plates at the ends of the steel-wrapped UHPC precast beams are first welded to the tension screws, and then precise measurements are made using equipment such as total stations or theodolites to determine the position and elevation of the support installation. The steel-wrapped UHPC precast beams are hoisted by a gantry and slowly moved to the predetermined position. Through the fine adjustment function of the gantry, the embedded steel plates of the crown beams at both ends of the steel-wrapped UHPC precast beams are located directly above the side of the crown beam reinforcement cage of the foundation pit, with the error controlled at the millimeter level. The steel-wrapped UHPC precast beams are then slowly dropped down, and the bottom of the UHPC precast beams and the rubber bearings are bolted to ensure that the centers of the two are aligned. Finally, the concrete formwork for the crown beam and the wet connection is erected, and concrete is poured at the crown beam and the wet connection at the same time, so that the crown beam and the wet connection become a whole, which better guarantees the axial tension transmission mechanism.

[0066] After the prefabricated beams are installed, the prefabricated bridge deck is hoisted, and the connectors, high-strength bolts and bolt holes are accurately aligned. The prefabricated bridge deck is then slowly lowered, and the connectors and high-strength bolts of the prefabricated bridge deck connection section are fixed with nuts. After all the bolts are fixed, the stability of the support system is comprehensively checked to confirm that all connection parts are stable and the bolt torque meets the standards.

[0067] After the construction of this project is completed, when the connecting structure is dismantled, the last safety check before dismantling is first carried out to confirm the status of the supporting structure and the safety of the surrounding environment. The bolts of the UHPC prefabricated bridge deck connection section are removed one by one in diagonal order. After ensuring that all the connecting bolts are loose, the UHPC prefabricated bridge deck is then lifted by a gantry, and the UHPC prefabricated bridge deck is slowly separated from the connector and slowly lifted out of position. The wet connection is then chiseled open, the tension screws on the steel plate at the end of the beam and the bolts of the rubber bearing are unscrewed, and the steel-wrapped UHPC prefabricated beam is slowly lifted out of position, avoiding obstacles and smoothly transferred to the designated storage or recycling area to ensure that no collision damage occurs during the process, so that the UHPC prefabricated components can continue to be recycled in the next project.

[0068] A method for installing a detachable beam-slab support-bearing UHPC blanket structure, the method comprising the following steps: S1: Forming of UHPC prefabricated beams wrapped with steel: Process I-shaped steel, weld shear keys on the web of the steel, and form anchor holes by laser cutting in the factory at the position avoiding the shear point and the maximum bending moment. After processing, weld 3-5cm thick steel plates on the end faces of the steel to form beam end steel plates to ensure that the beam end steel plates are tightly connected. Because of the beam end steel plates at the ends, there is no need to set up templates at the ends when pouring UHPC; then mechanically connect the tension screws to the beam end steel plates through suitable nuts.

[0069] Process the connector and weld the anchor steel bars outside the connector. After completion, weld the connector to the top of the upper wing plate of the steel section according to the position set in the drawing; Processing cross braces; A casting mold for UHPC prefabricated beams with steel sections is customized according to the design drawings, the processed steel sections are placed at the predetermined position in the mold, fixed with a positioning fixture, and UHPC is made according to the required UHPC mix ratio. Subsequently, UHPC is cast, and after high-temperature steaming for 24 hours, the above-mentioned template is removed, and then static curing for about 14 days is performed to obtain a prefabricated beam. The inner core of the prefabricated beam is steel sections, and the outer side is coated with UHPC material. It is a steel-concrete prefabricated component and is ready for use.

[0070] S2: Forming of prefabricated bridge deck: According to the design drawings, the template of the overlapped part of the prefabricated bridge deck is processed to facilitate the pouring of the prefabricated bridge deck; the tongue and groove are formed at the end of the prefabricated bridge deck and high-strength bolts are embedded in advance. Similarly, the splicing seam connection section is prefabricated or machine-formed, and bolt sleeves are embedded in the splicing seam connection section. The prefabricated bridge deck and splicing seam connection section are obtained through curing and are ready for use.

[0071] Furthermore, the prefabricated bridge deck is a customized UHPC prefabricated bridge deck according to the design drawings, and has higher strength. The prefabricated bridge deck contains a steel skeleton inside, and the steel skeleton is formed by cutting, bending and tying the steel bars, placed in a predetermined position in a mold, and fixed with a positioning fixture. UHPC is manufactured according to the required UHPC mix ratio, and then UHPC is poured. After high-temperature steaming for 24 hours, the above-mentioned template is removed, and it can be used after subsequent static curing for about 14 days.

[0072] S3: Forming of ground-connected walls, crown beams and corbels: According to the design drawings, the soil layer at the crown beam and corbel setting point is excavated, and the concrete formwork is erected. Then the steel cage is installed, and the crown beam embedded steel plate and anchor steel bars are pre-embedded. At the same time, the ground-connected walls, crown beams and corbels are cast. After curing for 72 hours, the above formwork is removed, and rubber bearings are set above the corbels to facilitate the installation of prefabricated UHPC prefabricated beams. At the same time, ear walls are set to increase lateral support, and you can choose whether to configure them.

[0073] S4: Transportation and hoisting: Use hoisting equipment to hoist the steel-wrapped UHPC precast beams, precast bridge decks and other components to the support area of ​​the foundation pit. During hoisting, adjust the angle and state of the steel-wrapped UHPC precast beams through the fine adjustment function of the gantry so that the bottom of the beam is located directly above the bridge support. Then slowly drop it to place the steel-wrapped UHPC precast beam in the middle of the ear wall so that the subsequent crown beam and wet connection can be cast simultaneously.

[0074] After hoisting into place, measure the verticality between the steel-wrapped UHPC prefabricated beams and the ground-connected walls on both sides, select a fixed point on the ground-connected wall as the measurement reference point, install the total station on a stable bracket, ensure that the instrument is level and stable, align the total station with the reference point, perform initial settings, use the laser ranging and angle measurement functions of the total station to measure multiple points on both sides of the prefabricated beam and the ground-connected wall respectively, directly read and record the verticality data, and adjust the verticality between the steel-wrapped UHPC prefabricated beams and the ground-connected wall according to the measurement results until an H-shaped support structure is formed. Finally, weld the tension bolts to the embedded steel plates of the crown beam for temporary fixation.

[0075] S5: Forming of crown beam and wet connection: Before pouring, comprehensively check the stability of the support system, confirm that all connection parts are stable and reliable, ensure that the tension screws at both ends of the precast beam are tightly connected with the welded steel plate and the embedded steel plate of the crown beam, and the stability of the bolts between the precast beam and the rubber bearing.

[0076] According to the design drawings, the casting formwork for the crown beam and wet connection is erected. The upper formwork is placed on the upper part of the embedded steel plate of the crown beam, and the bottom formwork is set above the corbel. Then the steel cage inside the crown beam is installed, and ordinary concrete is poured for the crown beam and wet connection. After 72 hours of curing, the above formwork is removed.

[0077] During the concrete pouring process, a vibrating rod is used to help the concrete slurry fill every corner of the mold and ensure that there are no air bubbles inside to avoid possible cracks and structural weaknesses in the future. The vibration of the concrete also helps to improve the bonding strength of the corner structure and ensure seamless connection between the corner structures. After the concrete is completely cured, the wet connection of the precast beam, beam end steel plate, tension screw, crown beam embedded steel plate and crown beam is officially completed.

[0078] S6: Cross brace, beam-plate, plate-plate connection: After the wet connection construction is completed, the cross brace is lifted by a gantry and moved to the cross brace position at the web of the precast beam. After fine adjustment, the steel plate is used to align the bolt holes, and then it is fixed with high-strength bolts.

[0079] After the cross brace connection is completed, the precast bridge deck is lifted by a gantry and moved above the UHPC precast beam wrapped with steel sections. The angle and state of the precast bridge deck are adjusted so that the socket is directly above the connector in the precast beam, and then it is slowly dropped to fit the connector with the socket. The high-strength bolts on the connector are passed through the bolt holes and tightened with nuts. The two precast bridge decks are connected using the splicing seam connection section and fixed with nuts.

[0080] S7: Disassembly of precast bridge decks: Disassembly of the bolts between precast bridge decks is the preliminary stage of the entire disassembly work. Before starting the disassembly, conduct appropriate safety checks to confirm that all disassembly tools are in good condition and the work area is safe and unobstructed. After the inspection, use appropriate safety equipment to gradually disassemble the bolts from the periphery to the center to maintain the stability of the structure. Construction workers need to use appropriate power tools to repeatedly rotate the bolt heads in a clockwise direction to eventually loosen them to remove the bolts connecting adjacent UHPC precast bridge decks.

[0081] After the high-strength bolts connecting the prefabricated bridge decks are removed, the same method is used to remove the high-strength bolts on the connectors. After ensuring that all the connecting bolts are loose, the UHPC prefabricated bridge deck is then lifted by a gantry, and the UHPC prefabricated bridge deck is slowly pulled out of the connectors, slowly lifted out of place, avoiding obstacles, and smoothly transferred to the designated storage or recycling area.

[0082] S8: Dismantling of precast beams: Dismantling work is usually done when the foundation pit construction project is completed. A vibrating chisel is usually used to open the wet connection. The remaining concrete on the outside of the beam end steel plate is removed by a cutting machine to ensure the integrity of the beam end steel plate. The nuts are then unscrewed to remove the bolts of the tension screws and rubber bearings, so that the entire steel-wrapped UHPC precast beam is separated from it. The precast beam is slowly lifted out of place, avoiding obstacles, and smoothly transferred to the designated storage or recycling area.

[0083] Because the removal of concrete is a relatively complicated measure, it is necessary to ensure that the precast beams are firmly fixed during the operation to prevent the precast beams from accidentally falling when the wet connection is damaged, and to provide high-altitude protection for the removal of waste. During the removal and transportation of the steel-wrapped UHPC precast beams and UHPC precast bridge decks, it is necessary to ensure that no collision damage occurs during the process, so that the steel-wrapped UHPC precast beams and UHPC precast bridge decks can be recycled in the next project.

[0084] In this example, the steel is outsourced to the UHPC prefabricated beam structure, where the steel structure has excellent tensile and bending properties, can provide excellent strength and rigidity, and UHPC has high compressive strength and durability, and can effectively withstand compressive stress and load. The steel and UHPC are combined to form a composite structure, making full use of the advantages of both materials. The steel is mainly subjected to tension and shear force, and the UHPC is mainly subjected to compressive stress. The two are subjected to force together, which improves the bearing capacity of the overall structure, reduces local stress concentration, and prolongs the use of the structure, thereby achieving the "support-bearing" integrated function.

Claims

1. A detachable beam-slab support-bearing UHPC blanket structure system, which adopts a structural system of UHPC prefabricated beams, prefabricated bridge decks and crown beams wrapped with steel, characterized by: The main body of the steel-wrapped UHPC prefabricated beam is a composite structural beam with internal steel and external UHPC shell, and beam end steel plates are arranged at both ends of the steel-wrapped UHPC prefabricated beam, and there is an upwardly extending plug-in on the steel-wrapped UHPC prefabricated beam; The prefabricated bridge deck (200) comprises a prefabricated bridge deck body (210) and a socket component (220), wherein the socket component is embedded in the prefabricated bridge deck as an embedded component, and two adjacent prefabricated bridge decks are fastened and connected via a splicing seam connection section (230); A wet connection structure is formed between the UHPC precast beam wrapped with steel and the crown beam, and a corbel (310) is arranged on the crown beam corresponding to the wet connection structure. Rubber bearings are arranged between the two ends of the UHPC precast beam wrapped with steel and the corbel for transition support. The wet connection structure (130) comprises a beam end steel plate (131), a tension screw (132), a crown beam embedded steel plate (133), anchoring steel bars (134) and cast concrete (135), wherein the anchoring steel bars (134) are welded to the back of the crown beam embedded steel plate and embedded in the crown beam (300), and the beam end steel plate (131) is welded to the steel (110) in the precast beam; one end of the tension screw (132) is mechanically connected to the beam end steel plate (131), and the other end is welded to the crown beam embedded steel plate; and the cast concrete (135) is filled in the space between the beam end steel plate (131) and the crown beam embedded steel plate; The plug-in connector and the socket connector are embedded and connected by interlocking in the form of male and female grooves.

2. A detachable beam-slab support-bearing UHPC blanket structure system according to claim 1, characterized in that: A pair of ear walls (330) are provided on the corbel (310), and the ear walls constrain the ends of the steel-encased UHPC prefabricated beams and both sides of the wet connection structure.

3. The detachable beam-slab support-bearing UHPC blanket structure system according to claim 1 is characterized in that: A high-strength bolt is welded on the upper part of the plug-in component, a bolt hole (221) is reserved on the top of the socket component, two layers of anchor steel bars (142) are welded on the outside, and the high-strength bolt passes through the bolt hole and is fastened by a nut.

4. A detachable beam-slab support-bearing UHPC blanket structure system according to claim 3, characterized in that: The connector and the socket are both cylindrical steel components, and both are steel shell structures.

5. A detachable beam-slab support-bearing UHPC blanket structure system according to claim 4, characterized in that: The inner diameter of the socket is slightly larger than the outer diameter of the connector by 1 mm to 2 mm, the bolt hole diameter is slightly larger than the high-strength bolt diameter by 1 mm, and the high-strength bolt is embedded in the bolt hole.

6. The detachable beam-slab support-bearing UHPC blanket structure system according to claim 1 is characterized in that: The edge of the joint connection section is configured as a serrated edge, and the two prefabricated bridge panels are mechanically engaged with each other via the serrated connection section.

7. The detachable beam-slab support-bearing UHPC blanket structure system according to claim 1 is characterized in that: Two adjacent steel-wrapped UHPC prefabricated beams are mechanically connected by cross braces or scissor braces.

8. The detachable beam-slab support-bearing UHPC blanket structure system according to claim 1 is characterized in that: Studs are welded at the web of the inner steel section (110) of the steel section outer-wrapped UHPC prefabricated beam to form a shear key (111), and anchor holes (112) are arranged at the web, wherein the anchor holes avoid the two ends of the steel section and the point with the maximum bending moment.

9. A method for installing a detachable beam-slab support-bearing UHPC blanket structure, comprising the following steps: S1: Forming of UHPC prefabricated beams wrapped with steel: Processing I-shaped steel, welding shear keys on the web of the steel, forming anchor holes by laser cutting at locations avoiding shearing and maximum bending moments, welding beam end steel plates on both ends of the steel, and then mechanically connecting the tension screws to the beam end steel plates through matching nuts; Process the connector and weld the anchor steel bars outside the connector. After completion, weld the connector to the upper wing plate of the steel section according to the position set in the drawing; Processing cross braces; Customize the casting mold for UHPC precast beams wrapped with steel according to the design drawings, place the processed steel at the predetermined position in the mold, fix it with a positioning fixture, cast UHPC, and remove the mold after high-temperature steam curing for 24 hours. Then, static curing is performed to obtain the UHPC precast beams wrapped with steel; S2: Forming of prefabricated bridge deck: according to the design drawings, the template is processed and the prefabricated bridge deck is cast and formed. The end of the prefabricated bridge deck has a tongue and groove and high-strength bolts are pre-embedded. The splicing seam connection section is prefabricated or machine-formed. Bolt sleeves are pre-embedded on the splicing seam connection section. The prefabricated bridge deck and the splicing seam connection section are obtained through curing and are ready for use; S3: Forming of ground-connected walls, crown beams and corbels: According to the design drawings, dig the soil layer at the crown beam and corbel setting point, set up the concrete formwork, then install the steel cage, and pre-embed the crown beam pre-embedded steel plate and anchor steel bars. At the same time, cast the ground-connected walls, crown beams and corbels. After curing, remove the formwork, set rubber bearings above the corbels, and set ear walls. S4: Transportation and hoisting: Use hoisting equipment to hoist the steel-wrapped UHPC precast beams and precast bridge decks to the area to be supported in the foundation pit. During hoisting, adjust the angle and state of the steel-wrapped UHPC precast beams so that the bottom of the beams are located directly above the bridge bearings, and then slowly drop them to place the ends of the steel-wrapped UHPC precast beams in the middle of the ear walls. After hoisting in place, measure the verticality between the steel-wrapped UHPC precast beams and the ground-connected walls on both sides. Select a fixed point on the ground-connected wall as the measurement reference point and install the total station. Align the total station with the reference point and perform initial settings. Use the laser ranging and angle measurement functions of the total station to measure multiple points on both sides of the steel-wrapped UHPC precast beams and the ground-connected wall, directly read and record the verticality data, and adjust the verticality between the steel-wrapped UHPC precast beams and the ground-connected wall based on the measurement results. Finally, weld the tension bolts to the crown beam embedded steel plate for temporary fixation. S5: Forming of crown beam and wet connection: Before pouring, fully check the stability of the support system, confirm that all connection parts are stable and reliable, ensure the effective connection between the tension screws at both ends of the steel-wrapped UHPC prefabricated beam and the welded steel plate, the crown beam embedded steel plate, and the stability of the steel-wrapped UHPC prefabricated beam and the rubber bearing bolts; According to the design drawings, the casting formwork for the crown beam and wet connection position is erected, the upper formwork is placed on the upper part of the embedded steel plate of the crown beam, and the bottom formwork is set above the corbel. Then the steel cage inside the crown beam is installed, and the ordinary concrete of the crown beam and wet connection is poured at the same time. After curing, the formwork is removed; S6: Cross brace, beam-slab, and slab-slab connection: After the wet connection construction is completed, the cross brace is lifted by a gantry and moved to the precast beam. After fine adjustment, it is fixed with high-strength bolts. After the cross brace connection is completed, the precast bridge deck is lifted by a gantry and moved above the steel-wrapped UHPC precast beam. The angle and state of the precast bridge deck are adjusted so that the socket is located directly above the connector in the precast beam, and then slowly dropped, the connector is engaged with the socket and fixed with nuts, and then the two precast bridge decks are connected using the splicing seam connection section and fixed with nuts.

10. The installation method of a detachable beam-slab support-bearing UHPC blanket structure according to claim 9, characterized in that: After step S6, a dismantling step S7 is also included: dismantling the prefabricated bridge deck: dismantling the bolts step by step from the periphery to the center, and dismantling the bolts connecting adjacent UHPC prefabricated bridge decks; after the high-strength bolts connecting the prefabricated bridge decks are dismantled, the high-strength bolts on the connectors are dismantled using the same method, and after ensuring that all the connecting bolts are loosened, the prefabricated bridge deck is lifted by a gantry, and the prefabricated bridge deck is slowly pulled out of the connector, slowly lifted out of the original position, avoiding obstacles, and smoothly transferred to a designated storage or recycling area; S8: Dismantling precast beams: Use a vibrating chisel to open the wet connection. For the remaining concrete on the outside of the beam end steel plate, use a cutting machine to cut it off to ensure the integrity of the beam end steel plate. Then unscrew the nuts to remove the bolts of the tension screws and rubber bearings, so that the entire steel-wrapped UHPC precast beam is separated and slowly lifted away, avoiding obstacles, and smoothly transferred to the designated storage or recycling area.

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