Pull-down type pre-pressing structure of cast-in-place beam support
By adopting a pull-down pre-pressing structure on the cast-in-place beam bracket, pull-down pre-pressing of the cast-in-place beam bottom formwork is achieved using a pull-in-place beam and a wire tightener, which solves the problem of high material consumption and difficult to control the accuracy in the existing pre-pressing method. , achieves the effect of simplifying construction, reducing costs and improving accuracy.
Patent Information
- Application Number
- CN202411902378.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-23
- Publication Date
- 2025-02-14
AI Technical Summary
The pre-pressing method of the existing bracket molding method has problems such as high material consumption, high cost, safety hazards, impact on construction progress and difficult to control the pre-pressing accuracy.
Using a pull-down pre-pressing structure, by erecting a bracket on the top of the cast-in-place beam bracket and setting a temporary support device between the bracket and the ground surface, pull-down pre-pressing of the cast-in-place beam bottom formwork is achieved using a drawstring and a wire tightening device.
It simplifies pre-pressure construction, reduces construction costs, improves pre-pressure accuracy, adapts to the conditions of narrow terrain and limited, and saves construction period.
Smart Images
Figure CN119434122A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the field of bridges, and in particular to a structure for pre-pressing a cast-in-place beam support by pulling down. Background Art
[0002] The bracket formwork method is a common method for the construction of bridge superstructures. Affected by factors such as assembly gaps, inelastic deformation, and uneven foundation settlement, the bracket must be pre-stressed after installation. The load distribution applied by the pre-stressing needs to simulate the construction load and bridge structure load to ensure the construction quality of the bridge superstructure.
[0003] At present, the preloading of the support formwork method generally adopts the sandbag preloading method and the water tank preloading method. After the bottom formwork of the support and the bridge superstructure is installed, sandbags or water tanks filled with water are piled on the bottom formwork, and the gravity of the sandbags and water tanks is used to preload the support formwork. The sandbag preloading method and the water tank preloading method have the following shortcomings: First, a large number of sandbags or water tanks filled with water need to be hoisted to the support during preloading, which consumes a large amount of preloading materials, is costly, and has safety hazards; second, the sandbags and water tanks occupy a large part of the space on the support, and subsequent construction can only be carried out after the water tanks and sandbags are removed, and the application and removal of the preloading load takes a lot of time, which seriously affects the construction progress; third, it is difficult to control the preloading accuracy of water tank and sandbag preloading, and it is difficult to accurately simulate the construction load and bridge structure load. It is difficult to achieve precise control in terms of load control, and accurate preloading cannot be achieved. Summary of the invention
[0004] The invention provides a pull-down pre-pressing structure of a cast-in-place beam support, aiming to simplify the structure of the support pre-pressing and improve the accuracy of the pre-pressing.
[0005] The technical solution adopted by the present invention is: a pull-down prestressing structure of a cast-in-place beam support, a support is set up between the tops of the piers, a temporary support device is provided between the support and the ground surface, the top of the support is a cast-in-place beam bottom formwork, and the cast-in-place beam bottom formwork is connected to at least one pull rope, the upper end of the pull rope is fixedly connected to the cast-in-place beam bottom formwork, and the lower end of the pull rope is fixedly connected to the ground anchor, and each pull rope is also provided with a tensioner.
[0006] In order to facilitate the measurement of the tension of each pull rope, further: a force measuring device is also provided on each pull rope, and the tensioner and the force measuring device on the same pull rope are arranged in series.
[0007] In order to facilitate the operation of the tensioner and the acquisition of data from the force measuring device, further: the tensioner and the force measuring device are arranged at a position close to the ground anchor.
[0008] The ground anchor remains fixed and provides downward tension to the pull rope when the tensioner tightens the pull rope. Specifically: The ground anchor is set under the ground or on the bridge pier.
[0009] When the tensioner tightens the pull rope, the upper end of the pull rope pulls down the cast-in-place beam bottom template to achieve pre-compression of the cast-in-place beam bottom template. Further, one anchor is connected to only one pull rope, or one anchor is connected to two or more pull ropes.
[0010] The pull rope directly applies a downward pulling force to the cast-in-place beam bottom formwork, thereby pre-pressing the cast-in-place beam bottom formwork. In order to accurately apply a vertical downward pre-compression load to the cast-in-place beam bottom formwork and reduce the force on the pull rope, further: the pull rope is arranged vertically.
[0011] In order to increase the force on the ground anchor and to provide stable support for the temporary supporting device, further: a support foundation is provided on the ground between the piers, the temporary supporting device is erected on the support foundation, the ground anchor is set in the stratum under the support foundation, the ground anchor is connected with a joint, the joint is exposed on the top surface of the support foundation, and the lower end of the pull rope is connected to the joint.
[0012] In order to disperse the downward pulling force of the pull rope on the cast-in-place beam bottom formwork, further: a pad and an anchor are placed on the top of the cast-in-place beam bottom formwork in sequence from bottom to top, a clip is provided in the anchor hole of the anchor, and the upper end of the pull rope passes through the cast-in-place beam bottom formwork, the pad and the anchor hole of the anchor and is fixed to the anchor through the clip.
[0013] Specifically: the pull rope is a steel wire rope, the pad is a steel plate, and the bracket is a Bailey frame.
[0014] The beneficial effects of the present invention are as follows: First, the present invention replaces the gravity of the traditional sandbags and water tanks with the downward pulling force of the pull rope, thus avoiding the work of hoisting the sandbags and filling the water tank, avoiding the waste of water resources, simplifying the construction of preloading, reducing the construction cost, and being able to adapt to the conditions of areas with narrow and restricted terrain and difficult lifting and hoisting. Second, a tensioner is arranged on the pull rope. When the tensioner tightens the pull rope, the upper end of the pull rope pulls down the cast-in-place beam bottom template, so as to achieve the effect of applying a preloading load to the cast-in-place beam bottom template, thereby achieving the effect of eliminating the assembly gap, inelastic deformation, and uneven settlement of the foundation of the temporary support device, and the downward pulling force of the pull rope is provided by operating the tensioner, and the downward pulling force is accurately controlled. Third, the present invention does not occupy the space above the cast-in-place beam bottom template, and the construction of the upper steel bars, templates and other processes can be carried out during the preloading period. The application and removal of the preloading load will not interfere with other processes, and the installation and disassembly are simple, which can effectively save the construction period. Fourth, through pre-design and calculation, under the premise of simulating construction load and bridge structure load, the pre-stressing position is accurately selected, and the connection position between the upper end of the pull rope and the bottom formwork of the cast-in-place beam is arranged accordingly, which can effectively control the pre-stressing accuracy, ensure the pre-stressing quality, and improve the quality of bridge construction. Fifth, components such as pull ropes and tensioners can be recycled and reused, and some buildings and structures under the bridge can be used as anchors, reducing resource waste and practicing the concept of green construction. BRIEF DESCRIPTION OF THE DRAWINGS
[0015] Figure 1 It is a schematic diagram of an embodiment of the pull-down prestressing structure of the cast-in-place beam support of the present invention.
[0016] Figure 2 yes Figure 1 Schematic diagram of the embodiment shown in which the upper end of the pull rope is fixedly connected to the cast-in-place beam bottom formwork.
[0017] Figure numerals: bridge pier 1, support 2, temporary supporting device 3, cast-in-place beam bottom formwork 4, pull rope 5, ground anchor 6, tensioner 7, force measuring device 8, support foundation 9, pad 10, anchor 11, clip 12. DETAILED DESCRIPTION
[0018] The present invention will be further described below in conjunction with the accompanying drawings.
[0019] like Figure 1 As shown, in the pull-down prestressing structure of the cast-in-place beam support of the present invention, a support 2 is set between the tops of the piers 1, a temporary support device 3 is set between the support 2 and the ground surface, and the top of the support 2 is a cast-in-place beam bottom template 4. In order to provide a stable support for the temporary support device 3, a support foundation 9 is constructed on the ground between the piers 1, and the temporary support device 3 is set on the support foundation 9. The pier 1 includes a pile foundation, a cap, a pier column, a cap beam and a cushion stone from bottom to top, and the top surface of the cast-in-place beam bottom template 4 is at the same height as the top surface of the cushion stone. The support 2 plays the role of directly supporting the cast-in-place beam bottom template 4, and the support 2 is generally a Bailey frame. The temporary support device 3 plays the role of supporting the support 2, and the temporary support device 3 is generally a scaffold. The cast-in-place beam bottom template 4 is connected to at least one pull rope 5, the upper end of the pull rope 5 is fixedly connected to the cast-in-place beam bottom template 4, and the lower end of the pull rope 5 is fixedly connected to the anchor 6, and each pull rope 5 is also provided with a tensioner 7. The anchor 6 remains fixed. When the tensioner 7 tightens the rope 5, the anchor 6 provides a downward pulling force for the lower end of the rope 5, and the upper end of the rope 5 pulls down the cast-in-place beam bottom formwork 4, so as to achieve the effect of pre-stressing the cast-in-place beam bottom formwork 4. The anchor 6 can be set under the ground or on the pier 1, for example, on the cap of the pier 1. The anchor 6 can also be set on an existing structure that can bear force, such as a retaining wall, a box culvert, and a roadbed. There are multiple ropes 5, and each rope 5 can be equipped with a ground anchor 6, that is, one anchor 6 is only connected to one rope 5, and the rope 5 corresponds to the anchor 6 one by one; in addition, multiple ropes 5 can be equipped with one anchor 6, that is, one anchor 6 connects two or more ropes 5. In order to reduce the force on a single anchor 6 and avoid the problem of too complicated structure caused by excessive force on a single anchor 6, it is best for the rope 5 to correspond to the anchor 6 one by one.
[0020] When determining the position of the guy rope 5 on the cast-in-place beam bottom formwork 4, the construction load and the bridge structure load are simulated according to the design of the bridge, and the prestressing load value and the distribution position of the prestressing point at various locations on the cast-in-place beam bottom formwork 4 are accurately calculated. Then, the connection position of the upper end of the guy rope and the cast-in-place beam bottom formwork is arranged accordingly, which can effectively control the prestressing accuracy, ensure the prestressing quality, and improve the bridge construction quality.
[0021] In order to facilitate the measurement of the tension of each pull rope 5, a force measuring device 8 is also provided on each pull rope 5, and the tensioner 7 and the force measuring device 8 on the same pull rope 5 are arranged in series. In order to facilitate the operation of the tensioner 7 and obtain the data of the force measuring device 8, the tensioner 7 and the force measuring device 8 are arranged near the anchor 6. In order for the pull rope 5 to accurately apply a vertical downward preload to the cast-in-place beam bottom formwork 4 and reduce the force on the pull rope 5, the pull rope 5 is preferably arranged vertically. In order to increase the force on the anchor 6, a support foundation 9 is constructed on the ground between the piers 1, and the anchor 6 is set in the stratum below the support foundation 9. The anchor 6 is connected with a joint, and the joint is used to connect with the lower end of the pull rope 5. For example, the joint is a pull ring, and the joint is exposed on the top surface of the support foundation 9. The lower end of the pull rope 5 is connected to the joint.
[0022] The pull rope 5 is generally a steel wire rope, and the upper end of the pull rope 5 is fixedly connected to the cast-in-place beam bottom template 4. Figure 2 As shown, the top of the cast-in-place beam bottom formwork 4 is sequentially placed with a pad 10 and an anchor 11 from bottom to top, the anchor 11 is provided with an anchor hole, a clip 12 is provided in the anchor hole, the cast-in-place beam bottom formwork 4 and the pad 10 are provided with aligned through holes, the upper end of the pull rope 5 passes through the through holes of the cast-in-place beam bottom formwork 4 and the pad 10, as well as the anchor hole of the anchor 11 and is fixed to the anchor 11 through the clip 12. The pad 10 plays a role in dispersing stress, and is generally a steel plate, and the through hole of the pad 10 is generally set at its center.
[0023] When preloading the cast-in-place beam bottom formwork 4, the tensioner 7 is used to tighten the drawstring 5 according to the pre-calculated preloading load until the downward pulling force of the drawstring 5 on the cast-in-place beam bottom formwork 4 reaches the preloading load. When tightening the drawstring 5, the tensioner 7 can be operated point by point and multiple times. After the downward pulling force of all the drawstrings 5 reaches the preloading load, it is maintained for a certain period of time to complete the preloading work. After the preloading is completed, the tensioner 7 is loosened, and all components except the anchor 6 are dismantled and recycled to carry out the subsequent construction process.
Claims
1. A cast-in-place beam support pull-down prestressing structure, wherein a support (2) is arranged between the tops of the bridge piers (1), a temporary support device (3) is arranged between the support (2) and the ground surface, and the top of the support (2) is a cast-in-place beam bottom formwork (4), characterized in that: The cast-in-place beam bottom formwork (4) is connected to at least one draw rope (5), the upper end of the draw rope (5) is fixedly connected to the cast-in-place beam bottom formwork (4), the lower end of the draw rope (5) is fixedly connected to the ground anchor (6), and each draw rope (5) is also provided with a tensioner (7).
2. The cast-in-place beam support pull-down pre-stressing structure according to claim 1, characterized in that: A force measuring device (8) is also provided on each pull rope (5), and the tensioner (7) and the force measuring device (8) on the same pull rope (5) are arranged in series.
3. The cast-in-place beam support pull-down pre-stressing structure according to claim 2, characterized in that: The tensioner (7) and the force measuring device (8) are arranged at positions close to the ground anchor (6).
4. The cast-in-place beam support pull-down pre-stressing structure according to claim 1, characterized in that: The ground anchor (6) is arranged under the ground, or arranged on the bridge pier (1).
5. The cast-in-place beam support pull-down pre-stressing structure according to claim 1, characterized in that: One ground anchor (6) is connected to only one pull rope (5), or one ground anchor (6) is connected to two or more pull ropes (5).
6. The cast-in-place beam support pull-down pre-stressing structure according to claim 1, characterized in that: The pull rope (5) is arranged vertically.
7. The cast-in-place beam support pull-down pre-stressing structure according to any one of claims 1 to 6, characterized in that: A support foundation (9) is constructed on the ground between the bridge piers (1), a temporary support device (3) is erected on the support foundation (9), a ground anchor (6) is set in the stratum below the support foundation (9), the ground anchor (6) is connected with a joint, the joint is exposed on the top surface of the support foundation (9), and the lower end of the pull rope (5) is connected to the joint.
8. The cast-in-place beam support pull-down pre-stressing structure according to any one of claims 1 to 6, characterized in that: A pad (10) and an anchor (11) are placed on the top of the cast-in-place beam bottom formwork (4) in order from bottom to top, a clip (12) is provided in the anchor hole of the anchor (11), and the upper end of the pull rope (5) passes through the cast-in-place beam bottom formwork (4), the pad (10) and the anchor hole of the anchor (11) and is fixed to the anchor (11) through the clip (12).
9. The cast-in-place beam support pull-down pre-stressing structure according to claim 8, characterized in that: The pull rope (5) is a steel wire rope, the pad (10) is a steel plate, and the bracket (2) is a Bailey frame.