A large segment prefabricated T-beam with step-by-step beam arrangement and its splicing method

Abstract

The present application relates to a prefabricated T-beam with large segments and a splicing method thereof, which belongs to the field of prefabricated concrete bridges; the T-beam is composed of a plurality of prefabricated segments with a length of 6 to 16 meters, a single prefabricated segment adopts pre-tensioned prestressed tendons to resist the forces in the hoisting and transportation stages, and the entire T-beam adopts full-length post-tensioned prestressed tendons to withstand the forces in the bridge completion and operation stages, forming a step-type force-bearing structure; the webs at the ends of the prefabricated T-beam segments are provided with shear-resistant concave key teeth, and a certain length of longitudinal main steel bars are extended from the top and bottom plates; a locking connection device with steel bar insertion holes, convex key teeth and corrugated pipe corrugated pipe bundle-through reserved holes is provided between adjacent segments; when splicing, the concave key teeth at the ends of the segments are closely spliced ​​with the convex key teeth, and the longitudinal main steel bars extending from the prefabricated segments are engaged and connected through radial locking members preset in the steel bar insertion holes, so as to realize the plug-in locking between the prefabricated segments, significantly reduce the construction difficulty and prestress loss, and effectively improve the spanning capacity and steel bar utilization rate of the prefabricated T-beam.

Description

Technical Field

[0001] The present application relates to the technical field of assembled concrete bridges, and in particular to a large-segment prefabricated T-beam with staged beams and a splicing method thereof. Background Art

[0002] Prestressed concrete T-beam bridges have the advantages of simple structure, clear force, material saving, easy erection and installation, and large span capacity. However, its maximum span should not exceed 40m in plain areas, and should not exceed 30m in mountainous areas. The main reasons for the limited span are, on the one hand, the limited transportation and hoisting construction, and on the other hand, the use of prestressed structure, which has a large arch after prestressing, affecting the bridge deck line shape and requiring the thickening of the bridge deck pavement.

[0003] In order to solve these problems, segmental prefabricated T-beams came into being. Compared with whole-hole prefabricated T-beams, segmental prefabricated T-beams are light in weight, small in size, and easy to transport, making them particularly suitable for the construction of large-span prefabricated bridges in urban and mountainous areas. However, segmental beams also have the problem of low shear bearing capacity, mainly because the joints are their weak links and are easily damaged under shear loads. Although traditional small-sized segmental beams can solve the problems of transportation and hoisting of large-span bridges, they have a large number of joints, which have an adverse effect on the integrity and durability of the bridge.

[0004] Therefore, segmental beams are gradually developing in the direction of large segments and fewer joints. Large segment T-beams not only solve the transportation and hoisting problems of large-span bridges, but are also closer to integral beams in terms of force. This idea is gradually being tried in the industry. For example, patent CN 111778864 A discloses a bridge and construction method of longitudinal segmented prefabricated small box beams, with segment length increased to 8m to 20m, and segments are spliced ​​with adhesive joints; however, the current design and application of such bridges mainly refers to traditional segment prefabrication and assembly technology, so there are certain problems and defects in prestressing technology and splicing technology.

[0005] In terms of prestressing technology, according to the above research findings, most large segment beams refer to traditional practices and adopt post-tensioned internal prestressing, or post-tensioned internal damage reduction external combined prestressing. However, when designing and calculating the structure of large segment T beams, it was found that since the self-weight of large segment beams is several times that of small segments, the tensile stress on the bottom edge is relatively large during the construction, lifting and transportation stages; and the pre-tensioned straight reinforcement is discontinuous at the joint, which leads to insufficient connection of the bottom edge joint, which is easier to open than traditional segment beams. Figure 1 Status shown.

[0006] In terms of splicing technology, traditional segmental beams use continuous wet joints with steel bars, which are closer to integral beams in terms of bending and shear performance than discontinuous dry joints and adhesive joints. However, the wet joint construction process is cumbersome and does not meet the needs of rapid construction. Therefore, how to improve the durability of the joints and the splicing speed has become an urgent problem to be solved. Summary of the invention

[0007] The embodiment of the present application provides a large-segment prefabricated T-beam with staged beam distribution and a splicing method thereof, so as to solve the problem in the related art that the large-segment beam has a self-weight several times that of the small segment, the bottom edge tensile stress is relatively large during the construction lifting and transportation stages, and the pre-tensioned straight reinforcement is discontinuous at the splicing point, resulting in insufficient connection of the bottom edge seam, which is easier to open than traditional segmental beams.

[0008] In a first aspect, a large segment prefabricated T-beam with step-by-step beam arrangement is provided, comprising:

[0009] Locking connection device;

[0010] A plurality of prefabricated segments, each of which is provided with a steel cage, and prestressed tendons and a corrugated pipe passing through the steel cage; a locking connection device is provided between two adjacent prefabricated segments; part of the longitudinal main steel bars of the steel cage extend out of the prefabricated segment and are connected in the locking connection device;

[0011] Post-tensioned prestressed tendons, which run through the corrugated tubes of all precast segments and connect multiple precast segments and lock-type connection devices in series to form a staged load-bearing precast beam;

[0012] The pre-tensioned prestressed tendons of the prefabricated segments of the step-type load-bearing prefabricated beam are used to resist the forces in the lifting and transportation stages, and the post-tensioned prestressed tendons are used to withstand the forces in the bridge completion and operation stages.

[0013] In some embodiments, part of the longitudinal main steel bars of the steel cage are located in the top plate and the bottom plate of the prefabricated segment; the prestressed tendons are located in the lower half of the prefabricated segment and above part of the longitudinal main steel bars of the steel cage of the bottom plate; and the corrugated pipe is located above the prestressed tendons.

[0014] In some embodiments, the end webs of two adjacent prefabricated segments are provided with anti-shear concave key teeth; the cross-sectional shape of the locking connection device is the same as the cross-sectional shape of the prefabricated segments; and convex key teeth that fit tightly and are spliced ​​with the anti-shear concave key teeth are provided on both end surfaces of the locking connection device.

[0015] In some embodiments, the locking connection device is provided with a steel bar insertion hole for aligning and inserting with part of the longitudinal main steel bars of the steel cage; a radial locking piece is provided on the inner wall of the steel bar insertion hole;

[0016] The lock-type connection device is also provided with a bellows bundle-passing reserved hole, which is connected to the bellows and allows post-tensioned prestressed tendons to pass through.

[0017] In some embodiments, the radial locking members are multiple in number and are divided into multiple groups along the axial direction of the steel bar insertion hole; each group of radial locking members is distributed in a circle with the center of the steel bar insertion hole as the center.

[0018] In some embodiments, the outer side of some longitudinal main steel bars of the steel cage is provided with outer edge threads; the inner wall of the steel bar insertion hole is provided with a connection groove;

[0019] The radial locking member comprises a spring and a limiting protrusion; one end of the limiting protrusion extends into the connecting groove and is connected to the inner wall of the connecting groove through the spring; the other end of the limiting protrusion is used to be connected in the thread gap of the outer edge thread.

[0020] In some embodiments, between two adjacent prefabricated segments, the length of a steel bar insertion hole is equal to the sum of the protruding length of part of the longitudinal main steel bars of the steel cage at the corresponding end in one of the prefabricated segments and the protruding length of part of the longitudinal main steel bars of the steel cage at the corresponding end in the other prefabricated segment.

[0021] In a second aspect, a method for splicing large segment prefabricated T-beams with step-by-step beam arrangement is provided, comprising the following steps:

[0022] An assembly platform is set up at the assembly construction site, and spaced jacking devices are arranged on the assembly platform; the jacking directions of the two jacking devices are arranged opposite to each other;

[0023] Hoist at least two prefabricated segments onto the assembly pedestal and between the two jacking devices; then hoist a locking connection device between two adjacent prefabricated segments;

[0024] Structural adhesive is applied to both ends of the locking connection device, and then at least one of the pushing devices is used to push the prefabricated segment, so that part of the longitudinal main steel bars of the steel cage are connected to the locking connection device, and the end face of the locking connection device is fitted with the end face of the prefabricated segment to form a structure to be post-tensioned;

[0025] The post-tensioning prestressed tendons are pulled and inserted into the corrugated pipe of the post-tensioning structure by a winch, and then tensioned to form a prefabricated beam with a step-by-step load.

[0026] The prefabricated load-bearing beams are hoisted to the designed position of the bridge, and then the joints between the beams, the cross diaphragms at the supports and the bridge deck pavement are constructed.

[0027] In some embodiments, prefabricating a single prefabricated segment comprises the following steps:

[0028] Build a steel cage of a single prefabricated segment, and insert corrugated pipes and pre-tensioned prestressed tendons inside the steel cage;

[0029] The formwork is erected, and then the concrete is poured and cured to form a single precast segment.

[0030] In some embodiments, the assembly base includes a slide rail on the top, a plurality of positioning plates located in the same straight line are movably provided on the slide rail, and the positioning plates are provided with limiting grooves in the same extension direction as the straight line; the limiting grooves are used to connect with the prefabricated segments and the bottom of the locking connection device.

[0031] The beneficial effects of the technical solution provided by this application include:

[0032] The embodiment of the present application provides a large-segment prefabricated T-beam with step-by-step bundles and a method for splicing the same. The prefabricated sections are provided with a locking connection device, a plurality of prefabricated sections, a steel cage is provided in the prefabricated section, and pre-tensioned prestressed tendons and a corrugated tube are passed through the steel cage. A locking connection device is provided between two adjacent prefabricated sections. Part of the longitudinal main steel bars of the steel cage extend out of the prefabricated section and are connected to the locking connection device. The post-tensioned prestressed tendons are passed through the corrugated tube, and the plurality of prefabricated sections and the locking connection device are connected in series to form a step-by-step load-bearing prefabricated beam. Combining the advantages of pre-tensioning and post-tensioning, the method of prestressing in a divided process is adopted. Pre-tensioning prestressed tendons are arranged in the precast segment to resist the bottom edge stress during the transportation and hoisting stages, prevent the occurrence of construction cracks, and make the force more reasonable. Post-tensioning prestressed tendons connect multiple precast segments and locking-type connection devices in series to withstand the forces during the completion and operation stages of the bridge. The pre-tensioning prestressed tendons of adjacent precast segments and part of the longitudinal main steel bars of the steel cage are inserted into the locking-type connection device, which also has the functions of bending and shear resistance of the precast segment joints and steel bar continuity, so it is not easy to open compared with traditional segment beams.

[0033] During splicing, the shear-resistant concave key teeth and the convex key teeth are closely spliced, and part of the longitudinal main steel bars and pre-tensioned prestressed bars of the extended steel cage are engaged with the radial locking pieces of the steel bar insertion holes to achieve rapid plug-in and locking between prefabricated segments. The present invention significantly reduces the construction difficulty and prestress loss, and effectively improves the spanning capacity and steel bar utilization rate of large-segment prefabricated T-beams. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0035] Figure 1This is a schematic diagram of the linear reinforcement and the discontinuous bottom of the reinforcement provided in the related art, and the seam is easy to open;

[0036] Figure 2 A schematic diagram of the internal reinforcement and stress reinforcement distribution of a single prefabricated segment provided in an embodiment of the present application;

[0037] Figure 3 A schematic diagram of the connection between two prefabricated segments and a locking connection device provided in an embodiment of the present application;

[0038] Figure 4 A schematic diagram of the structure of a locking connection device provided in an embodiment of the present application;

[0039] Figure 5 A schematic diagram of the connection between the radial locking member and the steel bar insertion hole provided in the embodiment of the present application;

[0040] Figure 6 A schematic diagram of the construction process of splicing large-segment prefabricated T-beams with staged bundles provided in an embodiment of the present application.

[0041] In the figure: 1. Prefabricated segment; 2. Part of the longitudinal main reinforcement of the reinforcement cage; 3. Pre-tensioned prestressed tendons; 4. Post-tensioned prestressed tendons; 5. Locking connection device; 500. Rebar insertion hole; 501. Reserved hole for the corrugated pipe bundle; 6. Protruding key teeth; 7. Radial locking piece; 700. Spring; 701. Limiting protrusion; 8. Assembly pedestal; 9. Shear-resistant recessed key teeth; 10. Pushing device. DETAILED DESCRIPTION

[0042] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0043] In terms of prestressing technology, according to the above research findings, most large segment beams refer to traditional practices and adopt post-tensioned internal prestressing, or post-tensioned internal combined with external prestressing. However, when designing and calculating the structure of large segment T beams, it was found that since the self-weight of large segment beams is several times that of small segments, the tensile stress on the bottom edge is relatively large during the construction, lifting and transportation stages; and the pre-tensioned straight reinforcement is discontinuous at the joints, which leads to insufficient connection of the bottom edge joints, making them easier to open than traditional segment beams. Figure 1 The open crack shown is marked A.

[0044] The embodiment of the present application provides a large-segment prefabricated T-beam with staged beam distribution and a splicing method thereof, so as to solve the problem in the related art that the large-segment beam has a self-weight several times that of the small segment, the bottom edge tensile stress is relatively large during the construction lifting and transportation stages, and the pre-tensioned straight reinforcement is discontinuous at the splicing point, resulting in insufficient connection of the bottom edge seam, which is easier to open than traditional segmental beams.

[0045] Please refer to Figure 2-Figure 6 A large segment prefabricated T-beam with step-by-step bundle arrangement, which is composed of a plurality of prefabricated segments with a length of 6 to 16 m, and includes:

[0046] Locking connection device 5;

[0047] A plurality of prefabricated segments 1, each of which is 6 to 16 m long; a steel cage, prestressed tendons 3 and a corrugated pipe passing through the steel cage are arranged in the prefabricated segment 1; a locking connection device 5 is arranged between two adjacent prefabricated segments 1; part of the longitudinal main steel bars 2 of the steel cage extend out of the prefabricated segment 1 and are connected in the locking connection device 5;

[0048] The post-tensioned prestressed tendons 4 pass through the corrugated tubes of all precast segments 1, and connect multiple precast segments 1 and the locking connection devices 5 in series to form a staged load-bearing precast beam; the pre-tensioned prestressed tendons 3 of the precast segments 1 of the staged load-bearing precast beam are used to resist the forces in the lifting and transportation stages, and the post-tensioned prestressed tendons 4 are used to withstand the forces in the bridge completion and operation stages.

[0049] The advantages of pre-tensioning and post-tensioning are combined above, and the method of prestressing in stages is adopted. Pre-tensioning prestressing tendons 3 are arranged in the precast segment 1 to resist the bottom edge stress in the transportation and hoisting stage, prevent the occurrence of construction cracks, and make the force more reasonable. Post-tensioning prestressing tendons 4 bear the force in the bridge completion and operation stages; part of the longitudinal main steel bars 2 of the steel cage of adjacent precast segments 1 are inserted into the locking connection device 5, which makes up for the defect of difficult setting of shear steel bars at the joints, improves the flexural ductility and durability of the joints, and also has the functions of bending and shear resistance and steel bar continuity of the precast segment 1 joints, so it is not easy to open compared with traditional segment beams.

[0050] The locking connection device 5 is made of weather-resistant steel, which has the effect of corrosion resistance and durability.

[0051] In some preferred embodiments, the specific arrangement of part of the longitudinal main steel bars 2, the prestressed tendons 3 and the corrugated tube of the steel cage is as follows:

[0052] Part of the longitudinal main steel bars 2 of the steel cage are located in the top and bottom plates of the precast segment 1; the prestressed prestressed tendons 3 are located in the lower half of the precast segment 1 and above the part of the longitudinal main steel bars 2 of the steel cage of the bottom plate; the corrugated pipe is located above the prestressed prestressed tendons 3. Such a structural arrangement makes the part of the longitudinal main steel bars 2 of the steel cage more effective in suppressing the bottom opening.

[0053] In some preferred embodiments, the end webs of two adjacent prefabricated segments 1 are provided with anti-shear concave key teeth 9; the cross-sectional shape of the lock-type connection device 5 is the same as the cross-sectional shape of the prefabricated segment 1; and the two end surfaces of the lock-type connection device 5 are provided with convex key teeth 6 that are closely fitted and spliced ​​with the anti-shear concave key teeth 9;

[0054] The locking connection device 5 is provided with a steel bar insertion hole 500 for aligning and inserting with part of the longitudinal main steel bars 2 and the pre-tensioned prestressed bars 3 of the steel cage; a radial locking member 7 is provided on the inner wall of the steel bar insertion hole 500;

[0055] The lock-type connection device 5 is also provided with a bellows bundle-passing reserved hole 501 , which is connected to the bellows and allows the post-tensioned prestressed tendons 4 to pass through.

[0056] The above realizes that when two adjacent prefabricated segments 1 are connected through a locking connection device 5, only part of the longitudinal main steel bars 2 of the steel cage need to be inserted into the steel bar insertion hole 500 to complete the connection, thereby realizing the rapid insertion and locking between the prefabricated segments 1. The present invention significantly reduces the construction difficulty and prestress loss, and effectively improves the spanning capacity and steel bar utilization rate of large-segment prefabricated T-beams.

[0057] To further improve the stability and firmness of the connection, the number of radial locking members 7 is multiple and they are divided into multiple groups along the axial direction of the steel bar insertion hole 500; each group of radial locking members 7 is distributed in a circle with the center of the steel bar insertion hole 500 as the center.

[0058] The principle structure of the mechanical automatic locking of the radial locking member 7 is as follows: the outer side of some longitudinal main steel bars 2 of the steel cage is provided with an outer edge thread; the inner wall of the steel bar insertion hole 500 is provided with a connecting groove;

[0059] The radial locking member 7 includes a spring 700 and a limiting protrusion 701; one end of the limiting protrusion 701 extends into the connection groove and is connected to the inner wall of the connection groove through the spring 700; the other end of the limiting protrusion 701 is used to connect to the thread gap of the outer edge thread. The above specifically illustrates the structure that only part of the longitudinal main steel bars 2 and the pre-tensioned prestressed bars 3 of the steel cage need to be extended into the steel bar insertion hole 500 to complete the connection, realize quick connection and locking, and ensure the effective transmission of stress between the steel bars.

[0060] In addition, in order to ensure the continuity of steel bars and stress bars, improve the bending and shear resistance of the joints of precast segment 1, and ensure the continuity of steel bars, the following settings are made:

[0061] Between two adjacent prefabricated segments 1, the length of a steel bar insertion hole 500 is equal to the sum of the protruding length of part of the longitudinal main steel bars 2 of the corresponding end steel bar cage in one prefabricated segment 1 and the protruding length of part of the longitudinal main steel bars 2 of the corresponding end steel bar cage in the other prefabricated segment 1. Figure 5 .

[0062] The present application also proposes a method for splicing large segment prefabricated T-beams with step-by-step beam arrangement, comprising the following steps:

[0063] Step 1: Set up an assembly platform 8 at the assembly construction site, and set spaced jacking devices 10 on the assembly platform 8; the jacking directions of the two jacking devices 10 are set opposite to each other;

[0064] Step 2: hoist at least two prefabricated segments 1 onto the assembly pedestal 8 and between the two jacking devices 10; then hoist a locking connection device 5 between two adjacent prefabricated segments 1; wherein, prefabricating a single prefabricated segment 1 includes the following steps: building a steel cage of a single prefabricated segment 1, inserting a corrugated pipe and prestressed tendons 3 inside the steel cage; setting up a formwork, then pouring concrete and curing it to form a single prefabricated segment 1. The hoisting equipment is Figure 6 The mark B in the figure is a beam lifting machine; specifically:

[0065] In the prefabrication factory, a plurality of segmental T-beams are prefabricated by the long-line method or the short-line method, a steel cage is built, a corrugated pipe and prestressed tendons 3 are inserted inside the steel cage, a side form and an end form with a shear key are set up, concrete is poured and cured, and after the formwork is removed, a shear-resistant recessed key tooth 9 is set at the end of the prefabricated segment 1.

[0066] The above locking connection device 5 reserves a steel bar insertion hole 500 in the factory according to the design connection position requirements. The inner diameter of the steel bar insertion hole 500 corresponds to the main steel bar connection joint. A radial locking piece 7 is arranged in the hole, and shear-resistant concave key teeth 9 are welded at the design position. Protective measures are taken after the production is completed.

[0067] Step 3: Apply structural glue to both ends of the locking connection device 5, and then use at least one of the pushing devices 10 to push the prefabricated segment 1, so that part of the longitudinal main steel bars 2 of the steel cage are connected to the locking connection device 5, and the end face of the locking connection device 5 is fitted with the end face of the prefabricated segment 1 to form a post-tensioned structure; refer to the attached Figure 6 , specifically:

[0068] Hoist the 1# prefabricated segment 1 onto the assembly pedestal 8 and between the two jacking devices 10, clean the impurities in the connection end surface and the hole, first splice the lock-type connection device 5 with the 1# prefabricated segment 1, and apply structural glue on the splicing surface of the prefabricated segment 1; the jacking device 10 supports the 1# prefabricated segment 1, and aligns the lock-type connection device 5 with the part of the longitudinal main steel bars 2 of the steel cage extending from the 1# prefabricated segment 1, and the other side jacking device 10 supports the lock-type connection device 5, and gives a jacking force to make the part of the longitudinal main steel bars 2 of the steel cage completely inserted into the lock-type connection device 5, and the shear-resistant concave key teeth 9 are closely attached to the convex key teeth 6;

[0069] Hoist the 2# prefabricated segment 1 onto the assembly pedestal 8, between the jacking device 10 and the 1# prefabricated segment 1, splice the 1# prefabricated segment 1 with the 2# prefabricated segment 1, apply structural adhesive on the splicing surface of the 2# prefabricated segment 1, slide the 2# prefabricated segment 1 to the splicing position through the jacking device 10, and before assembling, check whether there is deviation in the splicing surface height and center line of each segment, whether the slope of the top surface is consistent, and whether some longitudinal main steel bars 2 of the steel cage of the 2# prefabricated segment 1 and the lock-type connection device 5 are aligned; the jacking device 10 supports the 1# prefabricated segment 1, and the jacking device 10 on the other side pushes the 2# prefabricated segment 1 to achieve steel bar insertion and key teeth close contact. The subsequent segments are sequentially processed as above.

[0070] As described above, during the alignment splicing, the jacking device 10 should apply a certain jacking force in the radial direction so that the steel bars and stress bars engage with the radial locking members 7 in the steel bar insertion holes 500 to form a connection device to transmit the axial force.

[0071] Step 4: Use a winch to pull and install the post-tensioned prestressed tendons 4 in the corrugated pipe of the post-tensioned structure, and then tension them to form a step-type prefabricated beam; this step is specifically as follows:

[0072] The post-tensioned prestressed tendons 4 are pulled through the corrugated tube by a winch, and the post-tensioned prestressed tendons 4 are tensioned in accordance with the tensioning sequence and stages required by the design. After the tensioning is completed, the excess post-tensioned prestressed tendons 4 are cut off, and grouting is completed within the specified time to form a complete beam.

[0073] Step 5: Hoist the prefabricated load-bearing beams to the designed position of the bridge, and then carry out the construction of the joints between the beams, the cross diaphragms at the supports, and the bridge deck pavement.

[0074] In some preferred embodiments, a slide rail is provided on the top of the assembly base 8, and a plurality of positioning plates located in the same straight line are movably provided on the slide rail, and a limiting groove is provided on the positioning plate in the same direction as the straight line extension; the limiting groove is used to connect with the bottom of the prefabricated segment 1 and the locking connection device 5.

[0075] The limit groove ensures that the vertical center line of each segment beam is consistent. At the same time, the segment beam plate is slid through the positioning plate to check whether the joint surfaces are consistent and make adjustments in time.

[0076] Through the above description, the step-by-step combined prestressing is that the pre-tensioning and post-tensioning prestressed tendons are subjected to force in steps and in combination. During the prefabrication process of a single prefabricated segment 1, pre-tensioning prestressed tendons 3 are applied by the pre-tensioning method. The pre-tensioning prestressed tendons 3 bear their own weight and external loads during the hoisting and transportation stages of the prefabricated segment 1, thereby ensuring the structural safety of the prefabricated segment 1 during transportation and installation. After all the prefabricated segments 1 are spliced, the corrugated pipes of all the prefabricated segments 1 are inserted into the post-tensioning prestressed tendons 4 and tensioned to form the main load-bearing structure of the entire large-segment prefabricated T-beam during the bridge completion and operation stages. The design of the post-tensioning prestressed tendons 4 takes into account the stress characteristics and deformation requirements of the bridge, and can more effectively resist the effects of long-term loads and live loads, thereby improving the overall stiffness and durability of the bridge.

[0077] This application should note that:

[0078] The position, quantity and tension of the pre-tensioned prestressed tendons 3 and the post-tensioned prestressed tendons 4 require accurate prestress calculation and structural design to achieve efficient use of steel bars and prestressed tendons and reduce material consumption.

[0079] The prefabricated segment 1 needs to determine the maximum size and weight of the assembly unit according to the actual possible prefabrication, transportation and lifting conditions at the bridge construction site; preferably, the length of the prefabricated segment 1 is 6m to 16m, the number of segments is an odd number (≥3), and it is strictly forbidden to set segmented joints at the mid-span position. At the same time, the shape and size of the prefabricated segment 1 should be standardized to enhance interchangeability.

[0080] In the description of the present application, it should be noted that the terms "upper", "lower", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. Unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be a connection between the two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to the specific circumstances.

[0081] It should be noted that, in this application, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0082] The above description is only a specific implementation of the present application, so that those skilled in the art can understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest range consistent with the principles and novel features applied for herein.

Claims

1. A large segment prefabricated T-beam with step-by-step beam arrangement, characterized in that: It includes: Locking connection device (5); A plurality of prefabricated segments (1), each of which is provided with a steel cage, and prestressed tendons (3) and a corrugated tube passing through the steel cage; a locking connection device (5) is provided between two adjacent prefabricated segments (1); a portion of the longitudinal main steel bars (2) of the steel cage extends out of the prefabricated segment (1) and is connected to the locking connection device (5); the end webs of two adjacent prefabricated segments (1) are provided with shear-resistant concave key teeth (9); the cross-sectional shape of the locking connection device (5) is The cross-sectional shape is the same as that of the prefabricated segment (1); the two end surfaces of the locking connection device (5) are provided with convex key teeth (6) that are tightly fitted and spliced ​​with the shear-resistant concave key teeth (9); part of the longitudinal main steel bars (2) of the steel cage are located in the top plate and the bottom plate of the prefabricated segment (1); the prestressed prestressed tendons (3) are located in the lower half of the prefabricated segment (1) and above part of the longitudinal main steel bars (2) of the steel cage of the bottom plate; the corrugated pipe is located above the prestressed prestressed tendons (3); Post-tensioned prestressed tendons (4) penetrate the corrugated tubes of all prefabricated segments (1) and connect multiple prefabricated segments (1) and lock-type connection devices (5) in series to form a step-type load-bearing prefabricated beam; The pre-tensioned prestressed tendons (3) of the prefabricated segments (1) of the step-type load-bearing prefabricated beam are used to resist the forces in the hoisting and transportation stages, and the post-tensioned prestressed tendons (4) are used to withstand the forces in the bridge completion and operation stages.

2. The large segment prefabricated T-beam with step-by-step arrangement as claimed in claim 1, characterized in that: The locking connection device (5) is provided with a steel bar insertion hole (500) for being inserted into and aligned with a portion of the longitudinal main steel bars (2) of the steel cage; a radial locking piece (7) is provided on the inner wall of the steel bar insertion hole (500); The lock-type connection device (5) is also provided with a bellows bundle-passing reserved hole (501), the bellows bundle-passing reserved hole (501) is connected to the bellows and allows the post-tensioned prestressed tendons (4) to pass through.

3. The large segment prefabricated T-beam with step-by-step arrangement as claimed in claim 2 is characterized in that: The radial locking members (7) are multiple in number and are divided into multiple groups along the axial direction of the steel bar insertion hole (500); each group of radial locking members (7) is distributed in a circle with the center of the steel bar insertion hole (500) as the center.

4. The large segment prefabricated T-beam with step-by-step arrangement as claimed in claim 2, characterized in that: The outer sides of some longitudinal main steel bars (2) of the steel cage are provided with outer edge threads; the inner wall of the steel bar insertion hole (500) is provided with a connection groove; The radial locking member (7) comprises a spring (700) and a limiting protrusion (701); one end of the limiting protrusion (701) extends into the connecting groove and is connected to the inner wall of the connecting groove via the spring (700); the other end of the limiting protrusion (701) is used to be connected in the thread gap of the outer edge thread.

5. The large segment prefabricated T-beam with step-by-step arrangement as claimed in claim 4 is characterized in that: Between two adjacent prefabricated segments (1), the length of one of the steel bar insertion holes (500) is equal to the sum of the protruding length of part of the longitudinal main steel bars (2) of the steel bar cage at the corresponding end in one of the prefabricated segments (1) and the protruding length of part of the longitudinal main steel bars (2) of the steel bar cage at the corresponding end in the other prefabricated segment (1).

6. A method for splicing large segment prefabricated T-beams with step-by-step arrangement as claimed in claim 1, characterized in that: The following steps are involved: An assembly platform (8) is set up at the assembly construction site, and spaced jacking devices (10) are arranged on the assembly platform (8); the jacking directions of the two jacking devices (10) are arranged opposite to each other; At least two prefabricated segments (1) are hoisted onto an assembly pedestal (8) and positioned between two jacking devices (10); and then a locking connection device (5) is hoisted between two adjacent prefabricated segments (1); Structural adhesive is applied to both ends of the locking connection device (5), and then at least one of the pushing devices (10) is used to push the prefabricated segment (1) so that part of the longitudinal main steel bars (2) of the steel cage are connected to the locking connection device (5), and the end surface of the locking connection device (5) is affixed to the end surface of the prefabricated segment (1), thereby forming a structure to be post-tensioned; Using a winch to pull and insert post-tensioned prestressed tendons (4) in the corrugated pipe of the structure to be post-tensioned, and then tensioning to form a step-type prefabricated beam; The prefabricated load-bearing beams are hoisted to the designed position of the bridge, and then the joints between the beams, the cross diaphragms at the supports and the bridge deck pavement are constructed.

7. The method for splicing large segment prefabricated T-beams with step-by-step arrangement as claimed in claim 6 is characterized in that: Prefabrication of a single prefabricated segment (1) comprises the following steps: Building a steel cage of a single prefabricated segment (1), and inserting a corrugated tube and prestressed tendons (3) inside the steel cage; The formwork is erected, and then concrete is poured and cured to form a single precast segment (1).

8. The method for splicing large segment prefabricated T-beams with step-by-step arrangement as claimed in claim 6 is characterized by: The assembly platform (8) includes a slide rail on the top, a plurality of positioning plates located on the same straight line are movably provided on the slide rail, and the positioning plates are provided with limiting grooves extending in the same direction as the straight line; the limiting grooves are used to connect with the prefabricated segments (1) and the bottom of the locking connection device (5).

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