Truss arch bridge lower chord prestress reinforcing structure and concrete pouring system
Patent Information
- Application Number
- CN202611512934.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-09-28
- Publication Date
- 2026-11-03
AI Technical Summary
In existing technologies, the shear resistance of the old and new concrete interface of the lower chord of truss arch bridges is poor, the prestressing reinforcement efficiency is low and secondary reinforcement is not possible, the concrete in the arch back arc section is prone to segregation, and the sealing and venting effects of the formwork are poor, making it difficult to guarantee the quality of reinforcement.
The structure employs a dual-interface shear-resistant structure with toothed groove mechanical interlocking and expanded hole anchoring. The prestressed pipes are arranged horizontally with reserved reinforcement channels. The hinged pipe grooves are adapted to the arched contour. Concrete is poured in combination with guide ribs and arc-shaped sealing templates. High-pressure grouting components fill micro-cracks.
It significantly improves the bonding strength between new and old concrete, ensures uniform prestress coverage, has high reinforcement efficiency, enables secondary tensioning reinforcement, and significantly improves pouring density and construction quality.
Smart Images
Figure CN123027809A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of bridge reinforcement engineering technology, specifically to a prestressed reinforcement structure for the lower chord of a truss arch bridge and its concrete pouring system. Background Technology
[0002] Truss arch bridges are a common bridge type for mountain highways. The lower chord arch back section exhibits significant stress concentration at the corresponding nodes of the web members. Under long-term vehicle loads, environmental corrosion, and material aging, the upper edge of the lower chord is prone to transverse tensile cracking. If not reinforced in time, this cracking will continue to propagate, threatening the overall structural safety of the bridge. Currently, the common remedial method for this type of damage is to thicken the upper edge of the lower chord with concrete and apply prestressed reinforcement. Construction typically employs conventional techniques such as on-site formwork erection and pumped concrete pouring.
[0003] Existing reinforcement schemes have several shortcomings. First, the interface between new and old concrete is often roughened using ordinary flat surfaces, resulting in insufficient shear capacity. Under the repeated action of prestressing tension reaction and vehicle dynamic loads, the reinforced layer is prone to slippage and peeling. Conventional rebar anchoring uses straight bars with bonded anchorage, which has limited anchoring force and poor force transmission, failing to effectively disperse interface shear force. Second, prestressed ducts are mostly arranged in single-pipe configurations, leading to uneven coverage of the prestress field, low reinforcement efficiency, and often a one-time design without reserved reinforcement channels. This makes it impossible to implement secondary tensioning reinforcement later if the defects further develop. Third, the arch back has an arc-shaped profile, and the reinforcement section is narrow. During the inclined transport of high-flowability concrete, aggregates are prone to settlement and segregation, resulting in uneven strength of the cast body. Conventional formwork cannot adapt to the arc-shaped surface, leading to poor fit and grout leakage. Furthermore, poor ventilation at the top easily forms honeycomb voids, making it difficult to guarantee the quality of the casting.
[0004] Therefore, there is an urgent need to develop a prestressed reinforcement structure for the lower chord of a truss arch bridge, which features reliable interface anchorage, reasonable prestressing arrangement, the ability to be reinforced later, adaptability to arch-back arc construction scenarios, and guarantees the quality of concrete pouring. This structure, along with its supporting concrete pouring system, is suitable for the construction of arch-back arcs. Summary of the Invention
[0005] This invention aims to solve the problems in the prior art, such as poor shear resistance at the interface between new and old concrete, low efficiency of prestressed reinforcement and inability to perform secondary reinforcement, easy segregation of concrete in the arched section of the arch back, and poor sealing and venting effect of the formwork. It provides a prestressed reinforcement structure for the lower chord of a truss arch bridge and its concrete pouring system.
[0006] To achieve the above objectives, the present invention provides the following technical solution:
[0007] A prestressed reinforcement structure for the lower chord of a truss arch bridge includes a concrete substrate, prestressing components, and interface anchors. The concrete substrate includes a reinforcement section and tensioning sections with anchor heads at both ends. The reinforcement section is cast in close contact with the upper surface of the lower chord. The tensioning sections with anchor heads are located at both ends of the reinforcement section and are integrally cast with the reinforcement section. The prestressing components include a plurality of prestressing tubes, all of which are embedded in the reinforcement section. Within the anchor tensioning sections extending to both sides, at least one prestressed tube contains a steel strand, and the other prestressed tube contains a reserved channel; the interface anchor is located at the interface between the concrete substrate and the lower chord, and includes a toothed groove and multiple reinforcing bars. The toothed groove is a continuous toothed concave-convex structure formed by roughening the upper surface of the lower chord. The toothed groove extends transversely along the lower chord. One end of the reinforcing bar is anchored into the lower chord, and the other end is bent and placed within the concrete substrate.
[0008] Furthermore, the anchor tensioning section includes a stepped expansion section and an anchor force transmission component. The stepped expansion section gradually expands its cross-section outward from the end of the reinforced section and is cast into the upper surface of the lower chord. The joint surface between the stepped expansion section and the lower chord is provided with a shear groove.
[0009] Furthermore, the anchor head force transmission component includes a pressure-bearing anchor plate and a shear plate. The pressure-bearing anchor plate is vertically sleeved on the outer side of the end of the prestressed component, and the shear plate is vertically welded to the pressure-bearing anchor plate and embedded in the shear groove.
[0010] Furthermore, an anchoring expansion hole is provided in the lower chord, the reinforcing steel bar is embedded in the anchoring expansion hole, and the anchoring expansion hole is filled with expanding anchoring adhesive.
[0011] Furthermore, the two ends of the reserved channel are provided with detachable seals, and steel strands can be inserted after the seals are removed.
[0012] A concrete pouring system for a prestressed reinforcement structure of the lower chord of a truss arch bridge includes a conveying pipe unit and a sealed formwork unit. The conveying pipe unit includes multiple conveying pipe sections, fixed supports, and guide ribs. The conveying pipe sections are sequentially hinged together by hinged flanges to form a continuous conveying channel. The fixed supports are arranged at intervals along the upper surface of the lower chord and are hinged at the top to support each conveying pipe section. Guide ribs are provided on the inner wall of each conveying pipe section. The sealed formwork unit includes a formwork panel, outer ribs, and exhaust components. The formwork panel includes a side plate and a top plate. The top plate is located on the upper side of the side plate. The outer ribs are fixed to the outer side of the side plate. The exhaust components are spaced apart on the top plate. The sealed formwork unit and the surface of the lower chord form a closed pouring cavity that matches the shape of the concrete substrate. The discharge end of the conveying pipe unit is connected to the inlet of the sealed formwork unit.
[0013] Furthermore, the outer frame includes multiple vertical ribs and an arc-shaped base. The vertical ribs are arranged at intervals along the side plate. The bottom end of each vertical rib is fixed with the arc-shaped base. The bottom surface of the arc-shaped base is an arc surface that matches the curvature of the upper surface of the lower chord. The bottom surface of the arc-shaped base is provided with a sealing groove, and a sealing strip is installed in the groove.
[0014] Furthermore, the spacing of the guide ribs satisfies the design formula for preventing segregation of high-flowability concrete:
[0015]
[0016] In the formula, The spacing between the guide ribs; This refers to the inner diameter of the conveying pipe section; The slump spread of the high-flowability concrete to be poured; The reference spread of self-compacting concrete; The angle between the axis of the conveying pipe section and the horizontal plane; This is the lead factor, with a value ranging from 0.8 to 1.2; The flow regime matching index has a value of 0.4 to 0.6. The tilt angle influence index has a value of 0.2 to 0.3.
[0017] Furthermore, it also includes a high-pressure grouting assembly, which is disposed on the side plate at the lowest end of the sealed template unit and connected to the position of the prestressed pipe.
[0018] Furthermore, a grouting hole is provided on the side plate at the lowest end of the sealed template unit. The high-pressure grouting assembly includes a grouting pump, a grouting pipe, and a grouting end seat. The grouting end seat is sealed and fixed on the grouting hole. The grouting pump pumps the grout into the prestressed assembly through the grouting pipe.
[0019] Compared with the prior art, the present invention has the following significant advantages:
[0020] 1. The dual-interface shear structure, which combines toothed groove mechanical interlocking with enlarged hole anchoring, significantly improves the bonding strength between new and old concrete, avoids slippage and peeling of the reinforcement layer, and greatly enhances the reliability of the reinforcement.
[0021] 2. The prestressed pipes are arranged horizontally and have reserved reinforcement channels, resulting in uniform stress coverage, high reinforcement efficiency, and the ability to meet the secondary tensioning and reinforcement needs after the development of defects. They also have strong durability.
[0022] 3. The articulated pipe channel is adapted to the arched back arc contour, the spiral guide rib optimizes anti-segregation according to the inclination angle, and the arc-shaped sealing template is combined with staged venting, which significantly improves the pouring density and construction quality. Attached Figure Description
[0023] Figure 1 This is a schematic diagram of the overall layout of the concrete pouring system according to an embodiment of the present invention;
[0024] Figure 2 for Figure 1 A magnified view of part A in the image;
[0025] Figure 3 for Figure 1 A magnified view of part B in the image;
[0026] Figure 4 for Figure 1 A magnified view of part C;
[0027] Figure 5 This is a schematic diagram of a prestressed reinforcement structure according to an embodiment of the present invention. Figure 1 ;
[0028] Figure 6 for Figure 5 A magnified view of part D;
[0029] Figure 7 This is a schematic diagram of a prestressed reinforcement structure according to an embodiment of the present invention. Figure 2 ;
[0030] Figure 8 for Figure 7 A magnified view of part E in the image;
[0031] Figure 9 for Figure 7 A magnified view of part of F;
[0032] Figure 10 This is a schematic diagram of a prestressed reinforcement structure according to an embodiment of the present invention. Figure 3 ;
[0033] The components include: 1. Lower chord; 2. Concrete matrix; 21. Reinforced section; 22. Anchor head tensioning section; 221. Stepped expansion section; 222. Anchor head force transmission component; 2221. Bearing anchor plate; 2222. Shear plate; 223. Shear groove; 3. Prestressed component; 31. Prestressed pipe; 32. Steel strand; 33. Reserved channel; 331. Sealing component; 4. Interface anchor; 41. Toothed groove; 42. Reinforcing steel. 43. Anchoring and expanding hole; 5. Conveying pipe unit; 51. Conveying pipe section; 52. Hinged flange; 53. Fixed bracket; 54. Guide rib; 6. Sealed template unit; 61. Template panel; 611. Side plate; 612. Top plate; 62. Outer rib; 621. Vertical rib; 622. Sealing strip; 63. Exhaust device; 7. High-pressure grouting assembly; 71. Grouting pipe; 72. Grouting end seat. Detailed Implementation
[0034] To facilitate understanding of the present invention, a more complete description will be given below with reference to the accompanying drawings. Preferred embodiments of the invention are shown in the drawings. However, the invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the invention.
[0035] The following is combined Figures 1 to 10 The following describes embodiments of the present invention.
[0036] According to an embodiment of the present invention, a prestressed reinforcement structure for the lower chord of a truss arch bridge is provided, comprising a concrete substrate 2, prestressing components 3, and interface anchors 4. The concrete substrate 2 includes a reinforcement section 21 and anchor tensioning sections 22 at both ends. The reinforcement section 21 is cast in close contact with the upper surface of the lower chord 1. The anchor tensioning sections 22 are located at both ends of the reinforcement section 21 and are integrally cast with the reinforcement section 21. The prestressing components 3 include a plurality of prestressing tubes 31, all of which are embedded within the reinforcement section 21. The prestressing tubes 31 extend into the anchor tensioning sections 22 on both sides. At least one prestressing tube 31 contains a steel strand 32, and the other prestressing tube 31 contains a reserved channel 33. The interface anchor 4 is set at the joint surface between the concrete substrate 2 and the lower chord 1, including a toothed groove 41 and multiple reinforcing bars 42. The toothed groove 41 is a continuous toothed concave-convex structure formed by roughening the upper surface of the lower chord 1. The toothed groove 41 runs through the lower chord 1 laterally. One end of the reinforcing bar 42 is anchored into the lower chord 1, and the other end is bent and set in the concrete substrate 2.
[0037] Specifically, the concrete substrate 2 serves as the carrier structure for prestressed reinforcement, providing enclosure and support for the prestressed components 3, while simultaneously increasing the cross-sectional area of the lower chord 1 to enhance the structure's bending capacity. The reinforced section 21 is the main thickened load-bearing section, corresponding to the stress concentration area of the lower chord 1, and shares the load through the added concrete cross-section. The anchor tensioning section 22 is the end anchorage area for prestressed tensioning, providing sufficient space to arrange tensioning anchors and force transmission structures to ensure effective prestress transfer.
[0038] The prestressed component 3 applies prestress to the tension zone at the upper edge of the lower chord 1 through the tensioned steel strands 32, counteracting the tensile stress generated by the load and inhibiting crack propagation. The prestressed tube 31 provides a passage and protection for the steel strands 32, preventing grout from encasing the steel strands 32 and affecting tensioning. The reserved channel 33 provides a backup channel for later reinforcement; if defects develop, additional steel strands 32 can be inserted for secondary tensioning without the need for re-grooving and drilling.
[0039] Interface anchor 4 is a key anchoring structure for the bonding of new and old concrete, ensuring that the concrete substrate 2 and the original lower chord 1 work together and preventing the reinforcement layer from peeling and slipping. The toothed groove 41, formed by roughening, creates a continuous concave-convex structure, increasing the friction coefficient and mechanical interlocking force at the interface between the new and old concrete, and bearing the interface shear force along the bridge axis. The reinforcing steel bar 42, inserted into the original beam and anchored into the new concrete, forms a cross-interface force transmission skeleton, transferring the internal force of the reinforcement layer to the interior of the original beam, thus improving the overall shear resistance of the interface.
[0040] In some embodiments, the anchor tensioning section 22 includes a stepped expansion section 221 and an anchor force transmission member 222. The stepped expansion section 221 gradually expands its cross-section outward in a stepped shape along the end of the reinforced section body 21 and is cast into the upper surface of the lower chord 1. The joint surface between the stepped expansion section 221 and the lower chord 1 is provided with an anti-shear groove 223.
[0041] Specifically, the stepped expansion section 221 gradually enlarges the end cross-section to disperse the concentrated reaction force at the end of the prestressed tensioning, thus avoiding localized bearing failure of the end concrete. The shear groove 223 is embedded in the original beam surface and cooperates with the anchor head force transmission component 222 to transmit the horizontal shear force at the end and prevent the anchor head from slipping along the joint surface.
[0042] In some embodiments, the anchor head force transmission component 222 includes a pressure-bearing anchor plate 2221 and a shear plate 2222. The pressure-bearing anchor plate 2221 is vertically sleeved on the outer side of the end of the prestressed component 3, and the shear plate 2222 is vertically welded to the pressure-bearing anchor plate 2221 and embedded in the shear groove 223.
[0043] Specifically, the pressure-bearing anchor plate 2221 is a direct load-bearing component for prestressed tensioning, which evenly distributes the tension reaction force of the steel strand 32 to the end concrete to avoid stress concentration. The shear plate 2222 is embedded in the shear groove 223 of the original beam to form a mechanical interlock, which transmits the shear force at the end interface and improves the anti-slip performance of the anchor head.
[0044] In some embodiments, an anchoring expansion hole 43 is provided in the lower chord 1, the reinforcing steel bar 42 is embedded in the anchoring expansion hole 43, and the anchoring expansion hole 43 is filled with expansion anchoring adhesive.
[0045] Specifically, the anchoring hole 43 is a drilled hole with an enlarged bottom. After curing with the expanding anchoring adhesive, it forms an inverted conical anchoring structure, which significantly improves the pull-out resistance of the reinforcing steel bar 42 and prevents the rebar from being pulled out and failing. The expanding anchoring adhesive fills the gap in the drilled hole, bonding the reinforcing steel bar 42 to the original beam concrete. At the same time, the micro-expansion effect tightens the hole wall, further enhancing the anchoring force.
[0046] In some embodiments, the two ends of the reserved channel 33 are provided with detachable seals 331, and steel strands 32 can be inserted after the seals 331 are removed.
[0047] Specifically, the seal 331 blocks the port of the reserved channel 33 during construction to prevent concrete slurry and debris from entering the channel and causing blockage, thus ensuring unobstructed passage. During later reinforcement, the seal 331 can be removed to insert the steel strand 32, making the operation convenient.
[0048] According to an embodiment of the present invention, a concrete pouring system for a prestressed reinforcement structure of the lower chord of a truss arch bridge is also provided, including a conveying pipe unit 5 and a sealed formwork unit 6. The conveying pipe unit 5 includes multiple conveying pipe sections 51, fixed supports 53, and guide ribs 54. The conveying pipe sections 51 are sequentially hinged together by hinged flanges 52 to form a continuous conveying channel. The fixed supports 53 are arranged at intervals along the upper surface of the lower chord 1, and are hinged at the top to support each conveying pipe section 51. Each conveying pipe section 51 has guide ribs 54 on its inner wall. The sealed template unit 6 includes a template panel 61, an outer frame 62, and an exhaust device 63. The template panel 61 includes a side plate 611 and a top plate 612. The top plate 612 is located on the upper side of the side plate 611. The outer frame 62 is fixed to the outer side of the side plate 611. The exhaust device 63 is spaced on the top plate 612. The sealed template unit 6 and the surface of the lower chord 1 form a closed pouring cavity that matches the shape of the concrete substrate 2. The discharge end of the conveying pipe unit 5 is connected to the inlet of the sealed template unit 6.
[0049] Specifically, the conveying pipe unit 5 serves as the channel for concrete delivery, adapting to the arc-shaped profile of the arch back to transport concrete from the lower level to the pouring section. The conveying pipe section 51 is a rigid section, ensuring conveying strength. It is rotatably connected via a hinged flange 52, allowing adjustment of the angle between adjacent pipe sections to conform to the arc-shaped profile of the arch back without bending the pipe. The fixed support 53 suspends the conveying pipe section 51 and fixes it to the surface of the arch back, preventing pipe displacement and providing hinged support to accommodate pipe section angle adjustments. The guide ribs 54 are located on the inner wall of the pipe, generating radial turbulence on the conveyed concrete, suppressing aggregate settlement, and preventing concrete segregation.
[0050] The sealed formwork unit 6 serves as the molding die for concrete pouring, enclosing and forming the designed cross-sectional shape of the reinforced section to ensure accurate concrete molding dimensions. The formwork panel 61 directly contacts the concrete, providing the molding surface. The side plates 611 and the top plate 612 together form a U-shaped groove structure, corresponding to the cross-sectional profile of the reinforced section. The outer frame 62 provides support rigidity for the formwork panel 61, preventing the formwork from bulging and deforming during pouring. The venting component 63 is used to expel air from the sealed pouring cavity, preventing the formation of air pockets and honeycomb inside the concrete and improving the compactness of the pouring.
[0051] In some embodiments, the outer frame 62 includes multiple vertical ribs 621 and an arc-shaped base. The vertical ribs 621 are arranged at intervals along the side plate 611. An arc-shaped base is fixed to the bottom end of each vertical rib 621. The bottom surface of the arc-shaped base is an arc surface that matches the curvature of the upper surface of the lower chord 1. A sealing groove is provided on the bottom surface of the arc-shaped base, and a sealing strip 622 is installed in the groove.
[0052] Specifically, the vertical ribs 621 are the main vertical support components of the formwork, bearing the lateral pressure of the concrete and ensuring the lateral stiffness of the formwork. The arc-shaped base conforms to the arched surface of the lower chord 1, increasing the contact area between the bottom of the formwork and the original beam, thus improving the stability of the support. The sealing groove is used to install and fix the sealing strip 622. When the sealing strip 622 is compressed, it fills the gap between the bottom of the formwork and the surface of the original beam, achieving a seal and preventing grout leakage during pouring.
[0053] In some embodiments, the spacing of the guide ribs 54 satisfies the design formula for preventing segregation of high-flowability concrete:
[0054]
[0055] In the formula, The spacing of the guide ribs 54; The inner diameter of the conveying pipe section 51; The slump spread of the high-flowability concrete to be poured; The reference spread of self-compacting concrete; The angle between the axis of the conveying pipe section 51 and the horizontal plane; This is the lead factor, with a value ranging from 0.8 to 1.2; The flow regime matching index has a value of 0.4 to 0.6. The tilt angle influence index has a value of 0.2 to 0.3.
[0056] Specifically, in this embodiment, the formula couples the inclination angle of the arched back pipe with the concrete flow parameters into the spacing design, solving the problem that conventional fixed spacing cannot adapt to the differences in aggregate settlement under different inclination angles.
[0057] in, The spacing of the guide ribs 54 is such that the smaller the spacing, the higher the turbulence intensity and the stronger the anti-segregation effect, but the greater the transport resistance. The inner diameter of the conveying pipe section 51 is a fundamental parameter that determines the conveying capacity and the scale of turbulence. The slump spread of high-flowability concrete to be poured reflects the flowability of the concrete. The greater the spread, the thinner the slurry, and the easier it is for the aggregate to settle. The reference spread of self-compacting concrete provides a reference benchmark for design. The angle between the axis of the conveying pipe section 51 and the horizontal plane is the angle of inclination. The larger the angle, the greater the component of gravity along the vertical direction of the pipe, and the stronger the tendency of aggregate to settle. is the lead factor, and is the correction factor, which matches the roughness of the pipe inner wall with the viscosity of the concrete. The flow regime matching index reflects the degree to which the flow regime of concrete affects settlement. The tilt angle influence index reflects the degree of influence of the tilt angle on aggregate settlement.
[0058] In the specific formula design, the design is carried out for the reinforcement of the lower chord of a commonly used truss arch bridge, with a conveying pipe section inner diameter of 51. Take 100mm as the slump spread of the high-flowability concrete to be poured. Take 650mm as the reference spread for self-compacting concrete. Take 600mm. The lower end of the arched back conveying pipe section has an inclination angle of 51. Take 12°, lead factor Set to 1.0, flow regime matching index Take 0.5, the tilt angle influence index Take 0.25. Substitute into the formula to calculate the spacing between the lower pipe sections. The arched high-end conveying pipe section has an inclined angle of 51. Taking 3°, we calculate the high-end pipe section spacing. .
[0059] In some embodiments, a high-pressure grouting assembly 7 is also included. The high-pressure grouting assembly 7 is disposed on the side plate 611 at the lowest end of the sealed template unit 6 and is connected to the position of the prestressed pipe 31.
[0060] Specifically, the high-pressure grouting component 7 is used to inject cement grout into the periphery and end gaps of the prestressed pipe 31 under high pressure after the concrete is poured, filling the micro-cracks and voids around the pipe caused by concrete shrinkage, improving the bonding performance between the prestressed component 3 and the concrete, and ensuring the effective transfer of prestress.
[0061] In some embodiments, a grouting hole is provided on the side plate 611 at the lowest end of the sealed template unit 6. The high-pressure grouting assembly 7 includes a grouting pump, a grouting pipe 71 and a grouting end seat 72. The grouting end seat 72 is sealed and fixed on the grouting hole. The grouting pump pumps the grout into the prestressed assembly 3 through the grouting pipe 71.
[0062] Specifically, the grouting holes are the channels and interfaces for grouting, and are located at the ends of the prestressed pipes 31. The grouting end seats 72 seal the connection between the grouting pipes 71 and the formwork side plates 611 to prevent grout leakage during grouting. The grouting pump provides high-pressure grouting power to force cement grout into the gaps around the prestressed pipes 31, filling them densely.
[0063] In this embodiment, the construction process of the reinforcement structure and casting system is as follows: First, clean the surface of the reinforcement section of the lower chord 1 arch back, chisel out the toothed groove 41 according to the design position, drill the anchoring expansion hole 43, insert the reinforcement steel bar 42 and inject the expansion anchoring adhesive. Install the anchor head force transmission component 222, embed the shear plate 2222 into the shear groove 223, and align the pressure anchor plate 2221 with the position of the prestressed pipe 31. Erect the sealed template unit 6, adjust the arc base to fit the arch back curved surface, and press the sealing strip 622 to achieve bottom sealing. Arrange the conveying pipe unit 5 along the arch back, fix the conveying pipe section 51 through the fixed bracket 53, adjust the angle of the hinge flange 52 to make the pipe fit the arc direction, and connect the discharge end of the conveying pipe section 51 to the low end inlet of the sealed template unit 6. Pump high-flowability concrete, the concrete is conveyed along the conveying pipe unit 5, and after being turbulent and preventing segregation by the guide rib 54, it enters the closed casting cavity. After the concrete is poured, grout is injected around the prestressed pipe 31 through the high-pressure grouting component 7 to fill the gaps. Once the concrete reaches its strength, steel strands 32 are inserted for tensioning and anchoring, completing the reinforcement. If further reinforcement is needed later, the sealing element 331 at the end of the reserved channel 33 is removed, and additional steel strands 32 are inserted for tensioning.
[0064] The specific embodiments described above do not constitute a limitation on the scope of protection of this application. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the scope of protection of this application.
Claims
1. A prestressed reinforcement structure for the lower chord of a truss arch bridge, characterized in that, Including concrete substrate, prestressed components, and interface anchors; The concrete matrix includes a reinforced section and two anchor tensioning sections at both ends. The reinforced section is cast in close contact with the upper surface of the lower chord. The anchor tensioning sections are located at both ends of the reinforced section and are integrally cast with the reinforced section. The prestressed component includes several prestressed tubes, all of which are embedded in the reinforced section. The prestressed tubes extend to the anchor tensioning sections on both sides. At least one prestressed tube contains a steel strand, and the other prestressed tube contains a reserved channel. The interface anchor is located at the interface between the concrete substrate and the lower chord, and includes a toothed groove and multiple reinforcing bars. The toothed groove is a continuous toothed concave-convex structure formed by roughening the upper surface of the lower chord. The toothed groove runs transversely along the lower chord. One end of the reinforcing bar is anchored into the lower chord, and the other end is bent and placed in the concrete substrate.
2. The prestressed reinforcement structure for the lower chord of a truss arch bridge according to claim 1, characterized in that, The anchor tensioning section includes a stepped expansion section and an anchor force transmission component. The stepped expansion section gradually expands its cross-section outward from the end of the reinforced section and is cast into the upper surface of the lower chord. The joint surface between the stepped expansion section and the lower chord is provided with a shear groove.
3. The prestressed reinforcement structure for the lower chord of a truss arch bridge according to claim 2, characterized in that, The anchor head force transmission component includes a pressure-bearing anchor plate and a shear plate. The pressure-bearing anchor plate is vertically sleeved on the outer side of the end of the prestressed component. The shear plate is vertically welded to the pressure-bearing anchor plate and is embedded in the shear groove.
4. The prestressed reinforcement structure for the lower chord of a truss arch bridge according to claim 1, characterized in that, An anchoring hole is provided in the lower chord, the reinforcing steel bar is embedded in the anchoring hole, and the anchoring hole is filled with expanding anchoring adhesive.
5. The prestressed reinforcement structure for the lower chord of a truss arch bridge according to claim 1, characterized in that, The two ends of the reserved channel are equipped with detachable seals, and steel strands can be inserted after the seals are removed.
6. A concrete pouring system for a prestressed reinforcement structure of the lower chord of a truss arch bridge, characterized in that, Includes delivery pipe unit and sealed template unit; The conveying pipe unit includes multiple conveying pipe sections, fixed supports, and flow guide ribs. The conveying pipe sections are sequentially hinged together by hinged flanges to form a continuous conveying channel. The fixed supports are arranged at intervals along the upper surface of the lower chord and are hinged at the top to support each of the conveying pipe sections. Flow guide ribs are provided on the inner wall of each of the conveying pipe sections. The sealed template unit includes a template panel, an outer frame, and venting components. The template panel includes a side plate and a top plate. The top plate is located on the upper side of the side plate. The outer frame is fixed to the outer side of the side plate. The venting components are spaced apart on the top plate. The sealed template unit and the surface of the lower chord form a closed pouring cavity that matches the shape of the concrete substrate. The discharge end of the conveying pipe unit is connected to the inlet of the sealed template unit.
7. The concrete pouring system for the prestressed reinforcement structure of the lower chord of a truss arch bridge according to claim 6, characterized in that, The outer frame includes multiple vertical ribs and an arc-shaped base. The vertical ribs are arranged at intervals along the side plate. The bottom end of each vertical rib is fixed with an arc-shaped base. The bottom surface of the arc-shaped base is an arc surface that matches the curvature of the upper surface of the lower chord. The bottom surface of the arc-shaped base is provided with a sealing groove, and a sealing strip is installed in the groove.
8. The concrete pouring system for the prestressed reinforcement structure of the lower chord of a truss arch bridge according to claim 6, characterized in that, The spacing of the guide ribs meets the design formula for preventing segregation of high-flowability concrete: ； In the formula, The spacing of the guide ribs; This refers to the inner diameter of the conveying pipe section; The slump spread of the high-flowability concrete to be poured; The reference spread of self-compacting concrete; The angle between the axis of the conveying pipe section and the horizontal plane; This is the lead factor, with a value ranging from 0.8 to 1.2; The flow regime matching index has a value of 0.4 to 0.
6. The tilt angle influence index has a value of 0.2 to 0.
3.
9. The concrete pouring system for a prestressed reinforcement structure of the lower chord of a truss arch bridge according to claim 6, characterized in that, It also includes a high-pressure grouting assembly, which is disposed on the side plate at the lowest end of the sealed template unit and connected to the position of the prestressed pipe.
10. The concrete pouring system for a prestressed reinforcement structure of the lower chord of a truss arch bridge according to claim 9, characterized in that, A grouting hole is provided on the side plate at the lowest end of the sealed template unit. The high-pressure grouting assembly includes a grouting pump, a grouting pipe and a grouting end seat. The grouting end seat is sealed and fixed on the grouting hole. The grouting pump pumps the grout into the prestressed assembly through the grouting pipe.