Fabricated frame beam-column joint for prestressed large cantilever beam of elevated station

Abstract

The invention relates to an assembly type frame beam-column joint for a prestressed large cantilever beam of an elevated station, which comprises a lower-layer pier column, the prestressed large cantilever beam, an upper-layer pier column and a longitudinal frame beam which are integrally prefabricated, prestressed tendons are preset in the prestressed large cantilever beam, and tensioning and anchoring are completed in the prefabrication stage; the large prestressed cantilever beam is fixed on the lower-layer pier column, a vertical reserved steel bar on the lower-layer pier column is connected with a pre-buried grouting sleeve in the large prestressed cantilever beam, the upper-layer pier column is fixed on the large prestressed cantilever beam, and a vertical reserved steel bar on the large prestressed cantilever beam is connected with a pre-buried grouting sleeve in the upper-layer pier column; the longitudinal frame beams are fixed to brackets preset on the two side faces of the large prestress cantilever beam, and post-pouring areas are arranged between the large prestress cantilever beam and the longitudinal frame beams and between the large prestress cantilever beam and the lower-layer pier column and between the large prestress cantilever beam and the upper-layer pier column. The problems that in the prior art, the construction error-tolerant rate is low, the degree of dependence on construction quality is high, and mechanical performance is difficult to guarantee are solved.

Description

Technical Field

[0001] The invention belongs to the technical field of rail transit engineering, and in particular relates to an assembled frame beam-column node for a prestressed large cantilever beam of an elevated station. Background Art

[0002] The bridge-building integrated double-column double-cantilever elevated station has been widely used in the field of urban rail transit due to its advantages of flexible architectural layout and small urban space occupation. At present, this type of elevated station mainly adopts cast-in-place construction, in which double columns are supported on the first floor and prestressed large cantilever beams are set on the station hall to bear the loads of each floor. In recent years, with the development of prefabricated building technology, the use of prefabricated structures to construct prestressed large cantilever beam frame nodes has become a research hotspot. However, the existing prefabricated nodes are mainly based on standards such as the "Technical Standard for Prefabricated Concrete Buildings" (GB / T 51231-2016) and the "Technical Code for Prefabricated Concrete Structures" (JGJ 1-2014), and no mature technical solutions for prestressed large cantilever beams of elevated stations have been formed.

[0003] There are many problems with the existing prefabricated technology when it is applied to the prestressed large cantilever beam of the elevated station. First, the prestressed tendons need to pass through the interface between the prefabricated layer and the post-casting layer, which makes positioning difficult and the construction quality difficult to guarantee. In addition, the prestressed tendons cannot be tensioned during the prefabrication stage and need to be tensioned after the construction of the post-casting area on site is completed, which weakens the advantages of the prefabricated technology. In addition, the steel bar connection point and the concrete interface are usually located in the internal force peak area of ​​the node, which makes the mechanical properties of the node highly dependent on the sleeve grouting and concrete interface treatment, the construction quality is highly sensitive, and the reliability is difficult to guarantee. At the same time, the post-casting method is adopted in the core area of ​​the node, which leads to the truncation of the force transmission path of the prestressed tendons, making anchoring difficult and affecting the mechanical properties of the overall structure. In addition, the low construction fault tolerance rate is also a major problem. The alignment requirements of the steel bars and the sleeves are high, the grouting quality is difficult to control, and the contact parts of the prefabricated parts are prone to local collapse under the action of seismic loads, which further affects the safety of the structure. Therefore, there is an urgent need for an assembled frame beam-column node technology that can improve construction accuracy, enhance the mechanical properties of the node, and have both construction convenience and stability. Summary of the invention

[0004] In view of the problems existing in the prior art of assembled nodes of prestressed large cantilever beams in elevated stations, such as poor mechanical performance reliability, low construction fault tolerance, high dependence on construction quality and difficulty in ensuring mechanical performance, the present invention provides an assembled frame beam-column node for prestressed large cantilever beams in elevated stations.

[0005] To achieve the above object, the technical solution of the present invention is as follows:

[0006] An assembled frame beam-column node for prestressed large cantilever beams of elevated stations, characterized in that it comprises an integrally prefabricated lower pier, a prestressed large cantilever beam, an upper pier, and a longitudinal frame beam, wherein prestressed tendons are preset in the prestressed large cantilever beam, and tensioning and anchoring are completed in the prefabrication stage, the prestressed large cantilever beam is fixed to the lower pier, the vertical reserved steel bars on the lower pier are connected to the embedded grouting sleeves in the prestressed large cantilever beam, the upper pier is fixed to the prestressed large cantilever beam, the vertical reserved steel bars on the prestressed large cantilever beam are connected to the embedded grouting sleeves in the upper pier, the longitudinal frame beam is fixed to the preset corbels on both sides of the prestressed large cantilever beam to realize temporary support of the longitudinal frame beam, and post-casting areas are arranged between the prestressed large cantilever beam and the longitudinal frame beam, and between the prestressed large cantilever beam and the lower pier and the upper pier.

[0007] Preferably, the vertical reserved steel bars on the lower pier column and the vertical reserved steel bars on the prestressed large cantilever beam are positioned and fine-tuned in the post-casting area between the prestressed large cantilever beam and the lower pier column and the post-casting area between the prestressed large cantilever beam and the upper pier column, respectively.

[0008] Preferably, the first horizontal reserved steel bar of the prestressed large cantilever beam is connected to the first horizontal reserved steel bar of the longitudinal frame beam, the second horizontal reserved steel bar of the prestressed large cantilever beam is connected to the second horizontal reserved steel bar of the longitudinal frame beam, and the first horizontal reserved steel bar is located below the second horizontal reserved steel bar.

[0009] Preferably, the first horizontal reserved steel bars are connected by U-shaped mutual anchoring or welding.

[0010] Preferably, the second horizontal reserved steel bars are connected by overlapping, mechanical connection of steel bars or welding of steel bars.

[0011] Preferably, the first horizontal reserved steel bars and the second horizontal reserved steel bars are connected and positioned finely adjusted in the post-casting area between the prestressed large cantilever beam and the longitudinal frame beam before being cast.

[0012] Preferably, core columns are provided at the top of the lower pier column and the bottom of the prestressed large cantilever beam, and the core columns are engaged and connected by protrusions and grooves during the construction phase to achieve self-stabilization and anti-slip during the construction phase.

[0013] Preferably, a core column is arranged at the bottom of the upper pier column, and the core column is connected to the prestressed large cantilever beam by engaging with protrusions and grooves during the construction stage, so as to achieve self-stabilization and anti-slip during the construction stage.

[0014] Preferably, a chamfer is provided on the outer edge of the upper surface of the prefabricated corbel preset on the prestressed large cantilever beam.

[0015] Preferably, the prestressed tendon is tensioned at the end point of the first prestressed tendon and anchored at the end point of the second prestressed tendon; or is tensioned at the end point of the second prestressed tendon and anchored at the end point of the first prestressed tendon; or is tensioned at both the end point of the first prestressed tendon and the end point of the second prestressed tendon.

[0016] Compared with the prior art, the advantages of the present invention are:

[0017] The present invention proposes an assembled frame beam-column node for prestressed large cantilever beams in elevated stations, which is suitable for elevated stations with integrated bridges and buildings in the road, as well as various industrial and civil buildings with prestressed components. This node prefabricates the prestressed large cantilever beam as a whole, and completes the tensioning and anchoring of the prestressed tendons in the prefabrication stage, effectively overcoming the problems of the prestressed tendons passing through the interface between the prefabricated layer and the post-cast layer, the difficulty in anchoring, and the unreliable transmission of prestress in the prior art, thereby achieving high reliability in prestressed design and construction. At the same time, the steel bar connection part in the node avoids the peak area of ​​internal force, and the steel bars are positioned and fine-tuned in the post-cast connection area, so that the mechanical properties of the node are stable and reliable, reaching or even equivalent to the effect of cast-in-place components. In addition, in order to solve the problems of low construction fault tolerance, high dependence on construction quality and difficulty in ensuring the mechanical properties of nodes in the prior art, the present invention sets a post-cast connection area in the node area, realizes the appropriate position adjustment between the reserved steel bars and the grouting sleeve, and greatly improves the construction fault tolerance and connection quality; at the same time, by adopting the core column and the bite structure of the protrusion and the groove in the node connection component, the self-stabilization and anti-slip function in the construction stage is realized, the installation process is simplified, and the dependence on auxiliary measures such as scaffolding is eliminated, thereby giving full play to the high efficiency, convenience and safety advantages of the prefabricated construction technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a node diagram of the cross-section direction of an elevated station in an embodiment of the present invention;

[0019] Figure 2 It is a node diagram of the longitudinal section direction of an elevated station according to an embodiment of the present invention;

[0020] Figure 3 This is a node installation diagram of the cross-section direction of an elevated station according to an embodiment of the present invention;

[0021] Figure 4 It is a node installation diagram of the longitudinal section direction of an elevated station according to an embodiment of the present invention;

[0022] Figure 5 A detailed installation diagram of a node installation according to an embodiment of the present invention;

[0023] Figure 6 A detailed structural diagram of a node installation according to an embodiment of the present invention;

[0024] Figure 7 Schematic diagram of the chamfering of the edge of a prefabricated corbel according to an embodiment of the present invention.

[0025] Explanation of the reference numerals: 1-lower pier; 2-prestressed large cantilever beam; 3-upper pier; 4-longitudinal frame beam; 5-corbel; 6-prestressed tendons; 7-post-casting area; 8-grouting sleeve; 9-vertical reserved steel bars; 10-first prestressed tendon end point; 11-second prestressed tendon end point; 12-first horizontal reserved steel bars; 13-second horizontal reserved steel bars; 14-core column; 15-protrusion; 16-groove; 17-chamfer. DETAILED DESCRIPTION

[0026] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention belong to the present invention.

[0027] In addition, described feature, structure or characteristic can be combined in one or more embodiments in any suitable manner. In the following description, many specific details are provided to provide a full understanding of the embodiments of the present application. However, those skilled in the art will appreciate that the technical scheme of the present application can be put into practice without one or more of the specific details, or other methods, components, devices, steps, etc. can be adopted. In other cases, known methods, devices, realizations or operations are not shown or described in detail to avoid blurring the various aspects of the application.

[0028] like Figure 1-7As shown, this embodiment discloses an assembled frame beam-column node for prestressed large cantilever beams of elevated stations, including an integrally prefabricated lower pier 1, a prestressed large cantilever beam 2, an upper pier 3, and a longitudinal frame beam 4, wherein prestressed tendons 6 are preset in the prestressed large cantilever beam 2, and tensioning and anchoring are completed in the prefabrication stage, so that the prestressed effect can be exerted immediately after installation, thereby improving the mechanical stability of the overall structure. The prestressed large cantilever beam 2 is fixed on the lower pier 1, and the vertical reserved steel bars 9 on the lower pier 1 are connected to the embedded grouting sleeves 8 in the prestressed large cantilever beam 2. Through the cooperation of the vertical reserved steel bars 9 and the grouting sleeves 8, a reliable connection can be formed by grouting after installation, thereby improving the overall force performance. The upper pier 3 is fixed on the prestressed large cantilever beam 2, and the vertical reserved steel bars 9 on the prestressed large cantilever beam 2 are connected to the embedded grouting sleeve 8 in the upper pier 3. Similarly, through the cooperation of the vertical reserved steel bars 9 and the grouting sleeve 8, a reliable structural integrity is formed between the upper pier 3 and the prestressed large cantilever beam 2. The longitudinal frame beam 4 is fixed on the preset brackets 5 on both sides of the prestressed large cantilever beam 2 to realize the temporary support of the longitudinal frame beam 4, without the need to set up scaffolding, so that the longitudinal frame beam 4 can rely on the brackets 5 to provide initial stability during the installation process, without the need for additional support measures, thereby improving construction efficiency and reducing construction costs. Post-casting areas 7 are set between the prestressed large cantilever beam 2 and the longitudinal frame beam 4, and between the prestressed large cantilever beam 2 and the lower pier 1 and the upper pier 3. The setting of the post-casting area 7 makes the connection between the components more stable. By pouring concrete in the later stage, the overall mechanical properties of the node are improved, so that it can reach or even be equivalent to the force effect of the cast-in-place node.

[0029] Furthermore, the vertical reserved steel bars 9 on the lower pier 1 and the vertical reserved steel bars 9 on the prestressed large cantilever beam 2 are positioned and fine-tuned in the post-casting area 7 between the prestressed large cantilever beam 2 and the lower pier 1 and the post-casting area 7 between the prestressed large cantilever beam 2 and the upper pier 3, respectively, to achieve high fault tolerance in construction. By positioning and fine-tuning the vertical reserved steel bars 9 between the lower pier 1 and the prestressed large cantilever beam 2 and between the prestressed large cantilever beam 2 and the upper pier 3 in the post-casting area 7, high fault tolerance in construction is achieved, which can ensure accurate alignment and integrity between the components when the concrete is post-cast, and further improve the mechanical properties and construction quality of the nodes.

[0030] In this embodiment, the first horizontal reserved steel bars 12 of the prestressed large cantilever beam 2 are connected to the first horizontal reserved steel bars 12 of the longitudinal frame beam 4, and the second horizontal reserved steel bars 13 of the prestressed large cantilever beam 2 are connected to the second horizontal reserved steel bars 13 of the longitudinal frame beam 4. The first horizontal reserved steel bars 12 are located below the second horizontal reserved steel bars 13. The first horizontal reserved steel bars 12 are connected by U-shaped mutual anchoring or welding to ensure the strength and reliability of the connection. The second horizontal reserved steel bars 13 are connected by overlapping, mechanical connection of steel bars or welding of steel bars, providing flexible construction options. The first horizontal reserved steel bars 12 and the second horizontal reserved steel bars 13 are connected and positioned in the post-casting area 7 between the prestressed large cantilever beam 2 and the longitudinal frame beam 4, and then cast. This ensures that the entire node is accurately positioned and integrated during the construction process, thereby improving the overall mechanical properties and construction quality of the node.

[0031] Furthermore, core columns 14 are arranged at the top of the lower pier 1 and the bottom of the prestressed large cantilever beam 2. The core columns 14 are engaged with each other through protrusions 15 and grooves 16 during the construction stage. A core column 14 is arranged at the bottom of the upper pier 3. The core column 14 and the prestressed large cantilever beam 2 are engaged with each other through protrusions 15 and grooves 16 during the construction stage. By arranging core columns 14 between the lower pier 1 and the prestressed large cantilever beam 2 and between the upper pier 3 and the prestressed large cantilever beam 2, and adopting the engagement connection method of protrusions 15 and grooves 16, it can be effectively ensured that the nodes have self-stabilization and anti-slip capabilities during the construction stage, and have strong shear bearing capacity. During concrete pouring and other construction processes, each component maintains accurate alignment and integrity, thereby improving the construction quality and seismic performance of the overall structure.

[0032] A chamfer 17 is provided at the outer edge of the upper surface of the prefabricated corbel 5 preset on the prestressed large cantilever beam 2. The chamfer 17 can reduce the stress concentration at the contact portion between the corbel 5 and the longitudinal frame beam 4, improve the deformation coordination of the component under stress, and achieve high ductility performance of the node under the action of longitudinal earthquake alternating loads. The prestressed tendon 6 is tensioned at the first prestressed tendon end 10 and anchored at the second prestressed tendon end 11. This method is suitable for the standard construction process to ensure the effective transfer of prestress; or tensioned at the second prestressed tendon end 11 and anchored at the first prestressed tendon end 10 to adapt to different construction conditions and equipment layouts, and improve the flexibility of tensioning operations; or tensioned at the first prestressed tendon end 10 and the second prestressed tendon end 11 at the same time, so that the prestressed tendon 6 is evenly stressed in the entire component, thereby optimizing the prestress distribution and improving the overall stress performance and construction adaptability of the structure. By prefabricating the prestressed large cantilever beam 2 as a whole and completing the tensioning of the prestressed tendons 6 during the prefabrication stage, the tensioning process of the prestressed tendons 6 can be completed during the prefabrication stage, avoiding the influence of on-site construction on the prestress, achieving high reliability of the construction quality of the node prestressing, and at the same time reducing the on-site tensioning process and improving the convenience of on-site installation. The overall prefabrication ensures that the node is uniformly stressed and improves the high reliability of the node mechanical quality.

[0033] In this embodiment, the steel bar connection points and most of the superimposed interfaces between post-cast and precast concrete avoid the internal force peak area of ​​the node, so that the node connection parts are in the area with relatively small internal forces, reducing the adverse effects of high stress on the connection strength and improving the reliability of the force transmission performance. The post-cast area is set at the key force transmission part of the connection area, so that the post-cast concrete and precast components are effectively combined to form an overall force system, which enhances the overall stiffness and shear resistance of the node, makes the mechanical properties of the node more stable and reliable, and achieves a force effect equivalent to that of the cast-in-place structure.

[0034] In summary, the present invention discloses an assembled frame beam-column node for prestressed large cantilever beams of elevated stations, the node comprising an integrally prefabricated lower pier column 1, a prestressed large cantilever beam 2, an upper pier column 3 and a longitudinal frame beam 4, by pre-setting prestressed tendons 6 in the prestressed large cantilever beam 2 and completing tensioning and anchoring in the prefabrication stage, and by setting a post-casting area 7 between the prestressed large cantilever beam 2 and the lower pier column 1, the upper pier column 3 and the longitudinal frame beam 4, the high reliability of the prestressed construction quality and the stability of the mechanical properties of the node are achieved; the steel bar connection The points and most of the overlapped interfaces between post-cast and precast concrete avoid the peak area of ​​the internal force of the node, and a post-cast area 7 is set at the key force transmission position, so that the concrete and the precast components form an overall force system, thereby improving the overall stiffness and shear resistance of the node, and the force transmission performance reaches or is equivalent to that of the cast-in-place structure; at the same time, by adopting the bite structure of the core column 14 and the protrusion 15 and the groove 16 in the node connection component, and setting the chamfer 17 on the precast corbel 5, the construction fault tolerance, self-stabilization ability and installation convenience are significantly improved, and the seismic performance of the node is effectively improved. The technical solution of the present invention not only achieves the remarkable technical effects of high construction fault tolerance, convenient installation and reliable node mechanical properties, but also has the advantages of high market fit and low conversion difficulty. Based on the currently most widely used bridge-building integrated double-column and double-cantilever cast-in-place elevated station structure system, the prefabricated node technology of the present invention is easy to be accepted by design, construction and other engineering and technical personnel, has strong conversion feasibility, and is applicable to a wide range of scenarios. It can be used not only for urban rail transit elevated stations, but also for various industrial and civil buildings with prestressed components. At a time when prefabricated technology is developing rapidly in the field of urban rail transit, the prefabricated technology of elevated stations is still in its infancy. The prefabricated frame beam-column node technology provided by the present invention will promote the improvement of the technical level in this field, promote the prefabricated transformation of rail transit projects and other related construction projects, and has significant social and economic benefits.

[0035] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them. Under the concept of the present invention, the technical features in the above embodiments or different embodiments may also be combined, the steps may be implemented in any order, and there are many other changes in different aspects of the present invention as described above, which are not provided in detail for the sake of simplicity. Although the present invention has been described in detail with reference to the above embodiments, a person of ordinary skill in the art should understand that the technical solutions described in the above embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. An assembled frame beam-column node for prestressed large cantilever beams of elevated stations, characterized in that: The invention comprises an integrally prefabricated lower pier column (1), a prestressed large cantilever beam (2), an upper pier column (3), and a longitudinal frame beam (4), wherein the prestressed large cantilever beam (2) is prefabricated with prestressed tendons (6), and tensioning and anchoring are completed in the prefabrication stage, the prestressed large cantilever beam (2) is fixed on the lower pier column (1), the vertical reserved steel bars (9) on the lower pier column (1) are connected to the embedded grouting sleeve (8) in the prestressed large cantilever beam (2), and the upper pier column (3) is fixed on the prestressed large cantilever beam (2). On the cantilever beam (2), the vertical reserved steel bars (9) on the prestressed large cantilever beam (2) are connected to the embedded grouting sleeves (8) in the upper pier column (3), and the longitudinal frame beam (4) is fixed on the preset brackets (5) on both sides of the prestressed large cantilever beam (2) to realize the temporary support of the longitudinal frame beam (4). Post-casting areas (7) are arranged between the prestressed large cantilever beam (2) and the longitudinal frame beam (4) and between the prestressed large cantilever beam (2) and the lower pier column (1) and the upper pier column (3).

2. The assembled frame beam-column node for prestressed large cantilever beams of elevated stations according to claim 1, characterized in that: The vertical reserved steel bars (9) on the lower pier column (1) and the vertical reserved steel bars (9) on the prestressed large cantilever beam (2) are respectively positioned and finely adjusted in the post-casting area (7) between the prestressed large cantilever beam (2) and the lower pier column (1) and the post-casting area (7) between the prestressed large cantilever beam (2) and the upper pier column (3).

3. The assembled frame beam-column node for prestressed large cantilever beams of elevated stations according to claim 2, characterized in that: The first horizontal reserved steel bar (12) of the prestressed large cantilever beam (2) is connected to the first horizontal reserved steel bar (12) of the longitudinal frame beam (4), and the second horizontal reserved steel bar (13) of the prestressed large cantilever beam (2) is connected to the second horizontal reserved steel bar (13) of the longitudinal frame beam (4), and the first horizontal reserved steel bar (12) is located below the second horizontal reserved steel bar (13).

4. The assembled frame beam-column node for the prestressed large cantilever beam of the elevated station according to claim 3 is characterized in that: The first horizontal reserved steel bars (12) are connected by U-shaped mutual anchoring or welding.

5. The assembled frame beam-column node for the prestressed large cantilever beam of the elevated station according to claim 3, characterized in that: The second horizontal reserved steel bars (13) are connected by overlapping, mechanical connection of steel bars or welding of steel bars.

6. The assembled frame beam-column node for the prestressed large cantilever beam of an elevated station according to claim 4 or 5, characterized in that: The first horizontal reserved steel bars (12) and the second horizontal reserved steel bars (13) are connected and finely positioned in the post-casting area (7) between the prestressed large cantilever beam (2) and the longitudinal frame beam (4) before being cast.

7. The assembled frame beam-column node for prestressed large cantilever beams of elevated stations according to claim 1, characterized in that: Core columns (14) are arranged at the top of the lower pier column (1) and the bottom of the prestressed large cantilever beam (2). The core columns (14) are engaged and connected by protrusions (15) and grooves (16) during the construction phase, thereby achieving self-stabilization and anti-slip during the construction phase.

8. The assembled frame beam-column node for the prestressed large cantilever beam of an elevated station according to claim 7, characterized in that: A core column (14) is arranged at the bottom of the upper pier column (3), and the core column (14) is engaged with the prestressed large cantilever beam (2) through a protrusion (15) and a groove (16) during the construction phase, thereby achieving self-stabilization and anti-slip during the construction phase.

9. The assembled frame beam-column node for prestressed large cantilever beams of elevated stations according to claim 1, characterized in that: A chamfer (17) is provided on the outer edge of the upper surface of a prefabricated corbel (5) pre-set on the prestressed large cantilever beam (2).

10. The assembled frame beam-column node for prestressed large cantilever beams of elevated stations according to claim 1, characterized in that: The prestressed tendon (6) is tensioned at a first prestressed tendon end point (10) and anchored at a second prestressed tendon end point (11); or is tensioned at a second prestressed tendon end point (11) and anchored at a first prestressed tendon end point (10); or is tensioned simultaneously at both the first prestressed tendon end point (10) and the second prestressed tendon end point (11).

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