Annular prestressed member for reinforcing tensile member
By using annular prestressed components on the bridge beam, the problems of insufficient tensile resistance, poor durability and high maintenance costs in the prior art are solved, and efficient reinforcement and durability improvement of the structure are achieved.
Patent Information
- Application Number
- CN202421663169.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-07-15
- Publication Date
- 2025-04-18
- Estimated Expiration
- 2034-07-15
AI Technical Summary
When the prior art improves the tensile resistance of bridge beams, there are problems such as passive stress on the steel bars that cause cracks to occur in the concrete structure, difficulty in handling the interface between the outsourcing steel plate and the concrete material, and strong reaction frames are required for external prestresses and high maintenance costs.
The annular prestressed member is used to implant steel bars on the surface of the original concrete beam, install prestressed pipelines and prestressed bundles, and tensioning is used to form an annular prestressed system to enhance the tensile bearing capacity of the beam.
It effectively improves the tensile bearing capacity of bridge beams, has good durability, has the same service life as existing structures, reduces the cost of later maintenance, and has small changes to the appearance of existing structures, without affecting the overall effect of the bridge.
Smart Images
Figure CN222771303U_ABST
Abstract
Description
Technical Field
[0001] The utility model belongs to the technical field of building components, and in particular relates to a circumferential prestressed component used for reinforcing a tensile component. Background Art
[0002] There are many bridge components that are mainly tensile, such as the upper crossbeam of the V-shaped pier. The tensile resistance of the crossbeam is the key to the entire component. When some existing bridges need to be rebuilt or expanded, how to improve the tensile resistance of the crossbeam is a key issue due to the increase in the load on the upper structure. The design of the tensile reinforcement of the crossbeam is directly related to the safety of the structure and its later durability.
[0003] Conventional structures for reinforcing this type of component mainly include: (1) adding concrete and steel bars to the outside of the component to be reinforced, and improving the bearing capacity by the tensile resistance of the steel bars; (2) installing an external steel plate on the outside of the existing structure, and improving the bearing capacity by the tensile resistance of the steel plate; (3) adding external prestressing force, setting reaction force brackets on both sides of the beam, and transferring the pressure of the prestressing force to the beam through the reaction force bracket, thereby increasing the tensile resistance of the beam.
[0004] For structure (1), it can be used when the load increase is not large. Since the steel bars are passively stressed, the concrete structure is still under tension, which is prone to cracks during operation, affecting the durability of the structure. For structure (2), the steel plate is externally wrapped. Since the steel plate and concrete are two different materials, the treatment of their interface becomes the key. If the treatment is not appropriate, the two materials will be poorly stressed together, affecting the joint participation of the structure in stress. For structure (3), external prestressing is used, and strong reaction frames need to be set on both sides of the beam, which has a great impact on the appearance of the structure. At the same time, the external prestressing needs to be replaced within a certain lifespan, and the subsequent maintenance cost is also high. Summary of the invention
[0005] The purpose of the utility model is to provide a circumferential prestressed member for reinforcing a tensile member. The utility model can achieve three goals: (1) strengthening the tensile bearing capacity of the structure; (2) having good durability, having the same service life as the existing structure, and reducing the subsequent maintenance costs; (3) having little change to the appearance of the existing structure, and not affecting the overall effect of the bridge.
[0006] The utility model proposes a circumferential prestressed member for tensile member reinforcement, which introduces the circumferential prestressed system commonly used in silo structures into bridge reinforcement, and combines it with the traditional cross-section enlargement reinforcement method to form a circumferential prestressed member for tensile member reinforcement. Combined with the stress characteristics and material properties of the member, the structural safety and durability are fully considered to determine the functions, layout methods and construction procedures of each part of the utility model.
[0007] The utility model proposes a circumferential prestressed member for reinforcing a tensile member, comprising: a newly added concrete layer, a prestressed beam, a prestressed pipe, an anchor plate and a deflector; wherein:
[0008] Transverse and longitudinal steel bars are implanted around the surface of the original concrete beam, and the prestressed pipe is arranged in an annular manner. Several prestressed pipes are sleeved from top to bottom on the original concrete beam implanted with steel bars. An anchor plate is provided in each prestressed pipe. Several tapered holes are opened on the anchor plate. The tapered holes on both sides of the anchor plate are in opposite directions to the tapered holes in the middle of the anchor plate, and the number of tapered holes on both sides of the anchor plate is the same as the number of tapered holes in the middle of the anchor plate. The prestressed bundle is composed of several sub-bundles, and the number of prestressed bundles is the same as the number of prestressed pipes. The sub-bundle at one end of the prestressed bundle is anchored in the tapered hole in the middle of the anchor plate through a clip, and the other end passes through the prestressed pipe, and its sub-bundle is anchored in the tapered holes on both sides of the anchor plate through a clip. The sub-bundles at both ends of the prestressed bundle are connected to jacks through deflectors respectively, and the prestressed bundle is tensioned by the jacks. A new concrete layer is cast around the original concrete beam with the prestressed bundle arranged in an annular manner, and a tensioning anchor groove is provided in the new concrete layer. The number of the tensioning anchor grooves is the same as the number of prestressed pipes, and the prestressed pipes are embedded in the tensioning anchor grooves.
[0009] In the utility model, the material of the newly added concrete layer adopts shrinkage-compensating self-compacting concrete to reduce the shrinkage effect of the new concrete.
[0010] In the present invention, the total cross-sectional area of the prestressed tendons is determined according to the stress conditions under the ultimate load-bearing capacity condition, and the arrangement of each tendon should comprehensively consider the structural dimensions of the beam and the need for tensioning in batches during the construction process.
[0011] In the utility model, the prestressed pipe is filled with slurry.
[0012] In the utility model, the prestressed pipe adopts a steel pipe at the turning part and a plastic corrugated pipe at the inner part.
[0013] The construction method of the utility model is as follows: measurement and layout, pretreatment of the surface of the original concrete beam, planting of reinforcement, tying of steel bars on the beam, installation of prestressed pipes, insertion of prestressed bundles (such as steel strands) into the prestressed pipes, formwork support, pouring of new concrete layers, and when the strength meets the requirements, prestressing is performed. When the construction requirements are met, grouting of the prestressed pipes and backfilling of the anchor grooves are performed.
[0014] The specific operation process of the circumferential prestressed component used for the reinforcement of the tensile component of the utility model is: measurement and layout → original concrete surface treatment → planting reinforcement → tying reinforcement → installing prestressed pipes → passing steel strands → supporting formwork → pouring concrete → tensioning prestress after the strength meets the requirements → pipe grouting → anchor groove backfilling.
[0015] The beneficial effects of the utility model are: the utility model uses annular prestressed steel bundles to actively apply pressure to improve the tensile resistance of the structure, and has good applicability and durability in similar structures. The device uses annular prestressed steel bundles as the main load-bearing components, giving full play to the characteristics of the prestressed steel bundles actively applying pressure to strengthen the tensile bearing capacity of the structure; at the same time, it has good durability, has the same service life as the existing structure, and reduces the cost of later maintenance; the appearance of the existing structure is slightly changed, and the overall effect of the bridge is not affected. BRIEF DESCRIPTION OF THE DRAWINGS
[0016] Figure 1 Schematic diagram of the facade layout of prestressed tendons.
[0017] Figure 2 Schematic diagram of the cross section of the beam.
[0018] Figure 3 Schematic diagram of the plane layout of prestressed tendons.
[0019] Figure 4 This is a plan view of the prestressing arrangement at the body turning position.
[0020] Figure 5 It is a plan view of the anchoring notch.
[0021] Figure 6 This is a schematic diagram of the annular prestressing of the fixed groove.
[0022] The numbers in the figure are: 1 is the newly added concrete layer; 2 is the prestressed steel strand; 3 is the tensioning anchor groove; 4 is the original concrete beam; 5 is the plastic corrugated pipe; 6 is the steel pipe; 7 is the anchor plate; 8 is the deflector; 9 is the jack. DETAILED DESCRIPTION
[0023] The present invention is further described below by way of embodiments in conjunction with the accompanying drawings.
[0024] Embodiment 1: Taking the reinforcement of a certain V-pier as an engineering example, the original concrete beam 4 is reinforced by using the utility model.
[0025] The original structure uses a V-shaped pier with a crossbeam (i.e., the original concrete beam 4). The original concrete beam 4 uses a solid section with dimensions of 3m (height) x 3.7m (width). It is a prestressed concrete structure. Due to the increase in upper loads, the tensile capacity of the existing beam is insufficient, and the tensile bearing capacity of the beam needs to be increased.
[0026] This time, the beam is reinforced by adding reinforced concrete sections on both sides of the existing beam. Annular prestressed tendons are set in the newly added concrete. After being tensioned by the annular prestressed anchors, pressure is actively applied to the beam to increase the tensile bearing capacity.
[0027] The cross-sectional width of the newly added concrete layer 1 is 50cm. The new concrete layer adopts shrinkage-compensating self-compacting concrete to reduce the shrinkage effect of the new concrete. The joint surface of the original concrete beam 4 needs to be roughened first, and then rebars are planted, and transverse and longitudinal steel bars are implanted to enhance the bonding effect. The newly added cross-sectional part of the original concrete beam 4 is arranged with circumferential prestressed steel strands 2, with a specification of 22-φ15.20, a total of 10 strands, arranged from top to bottom. For all components involving the combination of new and old concrete, the joints between the original components and the newly poured concrete must be roughened before construction. It is required to thoroughly remove the plaster layer or the damaged old concrete surface layer on the surface of the original concrete beam 4, and the coarse aggregate of the concrete should be exposed. The roughness of the roughened surface should reach more than 6.0mm. Drill holes and plant rebars in the roughened concrete beam section, and the bonding between the new and old concrete can be better increased by planting rebars.
[0028] Prestressed steel strand 2 uses epoxy coated prestressed steel strand. The steel strand specification is 1×7-φ15.20mm, and the nominal area of a single steel strand is 140mm 2 , standard strength is 1860Mpa, and controlled stress under anchor σcon=1395MPa. The anchor adopts an integrated annular prestressed tension anchor. The annular prestressed beam is set in the newly added section of the beam, which is the main load-bearing member and bears the horizontal force that needs to be reinforced; the total cross-sectional area of the prestressed beam is determined according to the stress condition under the limit of bearing capacity. The arrangement of each beam should comprehensively consider the structural dimensions of the beam and the need for batch tensioning during construction, and be evenly arranged up and down along the beam to ensure that the structural force distribution is uniform and reasonable.
[0029] The radial pressure is taken into consideration at the turning position of the prestressed beam, and the steel pipe 6 is used at the turning position of the prestressed pipe, and the remaining straight part is a plastic corrugated pipe 5. The annular prestressed tensioning anchor is set in the tensioning anchor groove of the newly added concrete, on the same anchor plate 7 with the same number of tapered holes but in opposite directions, and the head and tail of the steel bundle are anchored on the anchor plate 7 by a clip, and the steel bundle is led out through the deflector 8 and tensioned by a jack 9, and the anchor groove is sealed after grouting.
Claims
1. A hoop prestressed member for reinforcing a tensile member, comprising: Add concrete layer, prestressed tendons, prestressed pipes, anchor plates and deflectors; the features are: Transverse and longitudinal steel bars are implanted around the surface of the original concrete beam, and the prestressed pipe is arranged in an annular manner. Several prestressed pipes are sleeved from top to bottom on the original concrete beam implanted with steel bars. An anchor plate is provided in each prestressed pipe. Several tapered holes are opened on the anchor plate. The tapered holes on both sides of the anchor plate are in opposite directions to the tapered holes in the middle of the anchor plate, and the number of tapered holes on both sides of the anchor plate is the same as the number of tapered holes in the middle of the anchor plate. The prestressed bundle is composed of several sub-bundles, and the number of prestressed bundles is the same as the number of prestressed pipes. The sub-bundle at one end of the prestressed bundle is anchored in the tapered hole in the middle of the anchor plate through a clip, and the other end passes through the prestressed pipe, and its sub-bundle is anchored in the tapered holes on both sides of the anchor plate through a clip. The sub-bundles at both ends of the prestressed bundle are connected to jacks through deflectors respectively, and the prestressed bundle is tensioned by the jacks. A new concrete layer is cast around the original concrete beam with the prestressed bundle arranged in an annular manner, and a tensioning anchor groove is provided in the new concrete layer. The number of the tensioning anchor grooves is the same as the number of prestressed pipes, and the prestressed pipes are embedded in the tensioning anchor grooves.
2. The annular prestressed member for reinforcing a tensile member according to claim 1, characterized in that: The material of the new concrete layer is shrinkage-compensating self-compacting concrete.
3. The annular prestressed member for reinforcing a tensile member according to claim 1, characterized in that: The total cross-sectional area of the prestressed tendons is determined based on the stress conditions under the ultimate bearing capacity condition. The arrangement of each tendon should take into account the structural dimensions of the beam and the need for batch tensioning during construction.
4. The annular prestressed member for reinforcing a tensile member according to claim 1, characterized in that: The prestressed pipe is filled with slurry.
5. The annular prestressed member for reinforcing a tensile member according to claim 1, characterized in that: The prestressed pipe uses steel pipes at the turning points and plastic corrugated pipes at the inner parts.