Active balance cable tower concrete tooth block anchoring structure and design method

Abstract

The application discloses an active balance type cable tower concrete tooth block anchoring structure and a design method, which comprises a cable tower body, concrete tooth blocks and an anchoring assembly, the concrete tooth blocks are arranged on the inner side of the cable tower body in a relative arrangement mode, and the anchoring assembly is arranged on the two concrete tooth blocks. The application has the following predictable technical effects: the prestressed beam arranged between the two tooth blocks in the bridge direction of the cable tower is tensioned, the adverse load of the horizontal component of the stay cable on the concrete structure of the cable tower is greatly eliminated, the cable tower structure is in the best stress state, the balance force of the main span and the side span stay cable is actively applied, the annular prestress of the concrete cable tower anchoring area can be completely cancelled, and a series of problems, such as the main tower steel cutting, the inconvenient concrete vibration, the weakened structure bearing capacity and the complicated construction of the existing cable tower tooth block anchoring area caused by the annular prestress, are solved.

Description

TECHNICAL FIELD

[0001] The present application relates to a concrete anchoring structure, in particular to an active balance type cable tower concrete tooth block anchoring structure and a design method. BACKGROUND

[0002] Under the strong horizontal component force of the cable, the tower wall generates tensile stress. In order to ensure that the cable tower (cable) anchoring area has sufficient crack resistance and bearing capacity, the cable tower tooth block anchoring area currently bears the strong tension generated by the cable on the tower wall by setting U-shaped or cross-shaped prestressed beams, but the length of such prestressed beams, especially the transverse bridge direction, is too short, and the prestress loss is large. Since the passive force state of the cable tower anchoring area has not been fundamentally solved, the cable tower needs to be arranged with a large number of U-shaped or cross-shaped prestressed beams along the height direction, which has low work efficiency. In construction, it often conflicts with ordinary steel bars, and the ordinary steel bars need to be cut off, which not only seriously weakens the bearing capacity of the tower column itself structure, but also complicates the construction.

[0003] Chinese patent CN106835981B discloses a self-balancing type cable anchoring structure suitable for bridge piers and bridge towers, which comprises a column of a bridge pier and a bridge tower, and left and right cables anchored to the column. The column is a hollow structure with an arbitrary cross-sectional shape, a solid section is arranged in the column at the anchoring position of the left and right cables, and a trapezoidal anchoring tooth block structure is arranged at the upper part of the solid section. The trapezoidal anchoring tooth block structure and the solid section adopt a reinforced concrete structure, and the slope of the two sides of the trapezoidal anchoring tooth block structure ensures that the left and right cables can be vertically anchored on the trapezoidal anchoring tooth block structure along the axis thereof.

[0004] This structure directly transmits the vertical centripetal force to the column through a zipper, relies on the structure itself to bear the tension generated by the cable, and still belongs to a passive force state. It is easy to cause the main tower steel bar to be cut off due to the extrusion of the circumferential prestress, and has a series of problems such as inconvenience of concrete vibration, weakening of structure bearing capacity, and complicated construction. SUMMARY

[0005] The present application aims at the problems existing in the prior art, and provides an active balance type cable tower concrete tooth block anchoring structure and a design method.

[0006] To achieve the above-mentioned purpose, the technical scheme adopted by the present application is as follows:

[0007] The application discloses an active balance type cable tower concrete tooth block anchoring structure which comprises a cable tower body, concrete tooth blocks and anchoring assemblies, the concrete tooth blocks are arranged on the two sides of the inner wall of the cable tower body in a symmetrical mode, and the anchoring assemblies are arranged on the two concrete tooth blocks respectively.

[0008] Through the technical scheme, the cable tower body and the concrete tooth blocks provide stable installation positions for the anchoring assemblies, the anchoring assemblies apply prestressed beams to the two concrete tooth blocks, the horizontal component of the cable is greatly eliminated, the cable tower structure is in the best stress state, the steel beam anchoring steel lug facilitates the installation of the prestressed beam, the cable anchor plate can effectively spread the stress during tension to the cable tower body, disperses the concentrated force, and makes the structure more stable and durable, thereby prolonging the service life of the structure.

[0009] Optionally, the concrete tooth block is internally provided with a plurality of steel bars, and the plurality of steel bars extend to the inside of the cable tower body.

[0010] Through the technical scheme, the concrete tooth block is more closely connected with the cable tower body through the steel bars, the stability of the structure is effectively improved, the load upper limit of the structure is strengthened, the steel bar and the concrete are combined to have good integrity, the wrapped steel bar is not easy to be corroded, and the material is easy to obtain.

[0011] Optionally, the prestressed beam is composed of a plurality of low-retraction anchors, the plurality of low-retraction anchors are arranged in a horizontal mode and connected to the top of the steel beam anchoring steel lug at two ends respectively.

[0012] Through the technical scheme, compared with a conventional anchor structure, the low-retraction anchor greatly reduces the retraction amount of the prestressed steel cable after tensioning, effectively reduces the prestress loss, and obviously improves the stress state of the web plate.

[0013] A design method of the active balance type cable tower concrete tooth block anchoring structure comprises the following steps.

[0014] (1) Calculation of the material; according to the design drawings, the horizontal component force of the cable-stayed cable is calculated to obtain the balance force size provided by the prestressed beam, and the balance force can obtain the number of the required prestressed beam, and the number of the prestressed beam can obtain the size of the anchoring steel plate and the anchoring opening position;

[0015] (2) Anchoring preset; when the tower body and the concrete tooth block are poured, the cable-stayed cable anchor pad and the steel beam anchoring steel lug plate are pre-set on the concrete tooth block, and the steel beam anchoring steel lug plate is arranged on both sides of the cable-stayed cable anchor pad;

[0016] (3) Installation and tensioning of the prestressed beam; after the concrete tooth block reaches the design strength, the prestressed beam is installed, and the prestressed beam can be tensioned 1-4 times according to the structure stress condition, so as to ensure that the cable-stayed tower structure stress condition is good.

[0017] By actively applying the balance force of the main and side span cable-stayed cable, the annular prestress of the concrete cable-stayed tower anchoring area can be completely cancelled, and a series of problems caused by the annular prestress of the existing cable-stayed tower tooth block anchoring area, such as cutting of the main tower reinforcement, inconvenience of concrete vibration, weakening of the structure bearing capacity, and complicated construction, are solved.

[0018] Optionally, the cable-stayed cable corresponding to the top end of the tower body forms a bridge cable force T and a vertical angle a of the top end of the tower body, and the horizontal component force T of the cable-stayed cable is calculated as T 水平 = T·sina, and the maximum value of the two is taken, then the balance force size F provided by the prestressed beam is T N = T 水平 , the cross-sectional area of a single prestressed beam is A P , the prestressed beam tension control stress is δ obtained by material selection, and the coefficient λ is obtained by considering the prestress loss reduction in actual operation, so the number of the required prestressed beam is calculated as n

[0019] Through the above technical scheme, the worker can calculate the force value required by the prestressed beam according to the bearing value, which is convenient for the worker to select the material of the prestressed beam, can effectively save the cost under the condition of ensuring the stability of the structure, and can also use the corresponding material in different occasions.

[0020] Optionally, the number of prestressed anchoring points is determined by the number n of the prestressed beam, the arrangement of the prestressed anchoring point should meet the space requirement of the prestressed beam tensioning, the size of the anchoring steel plate and the anchoring opening position of the steel beam anchoring steel lug plate are determined according to the maximum horizontal cable force of the prestressed beam, and the steel beam anchoring steel lug plate is arranged on both sides of the cable-stayed cable anchor pad to ensure that the prestressed beam has enough tensioning operation space.

[0021] Through the technical scheme, the staff can arrange through the calculated anchoring point, accelerate the construction progress, and guarantee the stability of the structure, and reduce the intensity of manual operation.

[0022] Optionally, the pre-stressed beam can be tensioned for 1-4 times according to the structure stress condition, to ensure the good stress condition of the cable tower structure, and before the n-th tensioning of the cable, the maximum tension value of a single cable in the same side is T n ; when the pre-stressed beam is tensioned, the tension control stress of a single low-retraction anchor is T The pre-stress of the pre-stressed beam can balance the horizontal component of the cable after the tensioning, and when the pre-stressed beam is tensioned before the last tensioning of the cable, the tension control stress of a single low-retraction anchor is T

[0023] Through the technical scheme, the pre-stressed beam is calculated to calculate the stress condition of the cable tower structure, further guarantee the stability of the cable tower, and analyze the use condition and service life of the structure under different tensions, so that the structure can be further improved.

[0024] Compared with the prior art, the beneficial effects of the present application are:

[0025] 1. The cooperation of the tower body and the concrete tooth block provides a stable installation position for the anchoring assembly, the anchoring assembly installs the pre-stressed beam in the two concrete tooth blocks and actively applies tension to the two concrete tooth blocks, so that the pre-stressed beam is tensioned and tension is maintained on the two concrete tooth blocks, which greatly eliminates the adverse load of the horizontal component of the cable-stayed cable on the cable tower concrete structure, so that the cable tower structure is in the best stress state, the steel beam anchoring steel lug plate facilitates the installation of the pre-stressed beam, the cable-stayed cable anchor pad can effectively spread the stress during tensioning to the cable tower body, disperse the concentrated force, make the structure more stable and durable, and prolong the service life of the structure;

[0026] 2. By actively applying the balance force of the main and side span cable-stayed cables, the annular pre-stress of the concrete cable tower anchoring area can be completely cancelled, and a series of problems such as main tower steel bar cutting, concrete vibration inconvenience, structure bearing capacity weakening and complicated construction caused by annular pre-stress in the existing cable tower tooth block anchoring area are solved. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 It is a structure diagram of the active balance type cable tower concrete tooth block anchoring structure of the present application;

[0028] Figure 2 It is a structure diagram of a section of the concrete tooth block of the present application;

[0029] Figure 3 For the common tooth block force analysis diagram;

[0030] Figure 4 For the common tooth block force analysis diagram;

[0031] In the figure: 1, cable tower body; 2, concrete tooth block; 3, anchoring assembly; 21, steel bar; 31, steel beam anchoring steel lug plate; 32, cable anchoring plate; 33, prestressed beam; 331, low retraction anchor. DETAILED DESCRIPTION

[0032] The technical solutions of the present application will be clearly and completely described below with reference to the drawings in the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0033] In combination Figure 1 As shown in the figure, an active balance type cable tower concrete tooth block anchoring structure, comprising a cable tower body 1, a concrete tooth block 2 and an anchoring assembly 3, the concrete tooth block 2 is provided with two and is arranged on the inner walls of the cable tower body 1 on both sides respectively, and the anchoring assembly 3 is provided with two groups and is located on the two concrete tooth blocks 2 respectively; the anchoring assembly 3 comprises a cable anchoring plate 32 arranged on the inner wall of the concrete tooth block 2, and a steel beam anchoring steel lug plate 31 is vertically arranged on the concrete tooth block 2, the steel beam anchoring steel lug plate 31 is arranged on both sides of the cable anchoring plate 32, and the bottom of the steel beam anchoring steel lug plate 31 extends into the concrete tooth block 2; a prestressed beam 33 is further arranged between the two concrete tooth blocks 2, the two ends of the prestressed beam 33 are connected to the top of the two steel beam anchoring steel lug plates 31 respectively, and the prestressed beam 33 is used for applying tension to the two concrete tooth blocks 2; the cooperation of the cable tower body 11 and the concrete tooth block 2 provides a stable installation position for the anchoring assembly 3, the anchoring assembly 3 greatly eliminates the adverse load of the horizontal component of the cable on the cable tower concrete structure by applying the prestressed beam 33 in the two concrete tooth blocks 2, so that the cable tower structure is in the best stress state, the steel beam anchoring steel lug plate 31 facilitates the installation of the prestressed beam 33, the cable anchoring plate 32 can effectively spread the stress during tensioning to the cable tower body 11, disperse the concentrated force, make the structure more stable and durable, and prolong the service life of the structure.

[0034] The inside of the concrete tooth block 2 is provided with a plurality of steel bars 21, the plurality of steel bars 21 extend into the inside of the cable tower body 1, the concrete tooth block 2 is connected more closely through the steel bars 21 and the cable tower body 11, effectively improving the stability of the structure, and at the same time, strengthening the upper limit of the bearing capacity of the structure, the structure of the steel bar 21 and the concrete has good integrity, the wrapped steel bar 21 is not easy to corrode, and the material is easy to obtain.

[0035] The prestressed strand 33 is composed of multiple low-retraction anchors 331. The multiple low-retraction anchors 331 are arranged horizontally and their two ends are respectively connected to the steel strand anchoring lugs 31. Compared with the conventional anchor structure, the low-retraction anchors 331 significantly reduce the amount of retraction after the prestressed steel strand is released, effectively reducing its prestress loss and significantly improving the stress state of the web.

[0036] A design method for an actively balanced concrete toothed block anchorage structure for cable towers includes the following steps:

[0037] (1) Calculate the materials; calculate the horizontal component of the cable generated by the cable according to the design drawings to obtain the magnitude of the balancing force required by the prestressed tendons, and obtain the number of prestressed tendons required through the balancing force, and then obtain the size of the anchoring steel plate and the position of the anchoring hole through the number of prestresses.

[0038] (2) Anchoring pre-setting; When the main body of the cable tower and the concrete tooth block are poured, the cable anchor plate and the steel strand anchor ear plate are pre-set on the concrete tooth block, and the steel strand anchor ear plate is arranged on both sides of the cable anchor plate.

[0039] (3) Installation and tensioning of prestressed tendons; After the concrete toothed blocks reach the design strength, the prestressed tendons are installed. The prestressed tendons can be tensioned in 1 to 4 stages according to the stress condition of the structure to ensure that the stress condition of the tower structure is good.

[0040] By actively applying the balancing force of the main and side span cable stays, the circumferential prestress in the concrete tower anchorage zone can be completely eliminated, solving a series of problems caused by the circumferential prestress in the existing tower tooth block anchorage zone, such as the cutting of the main tower reinforcement 21, inconvenience of concrete vibration, weakening of structural bearing capacity, and complicated construction.

[0041] The angle α between the cable force T formed by the stay cables at the top of the main tower 1 and the top of the main tower 1 and the vertical angle between the stay cables and the top of the main tower 1 is calculated. The horizontal component T generated by the stay cables is calculated respectively. 水平 =T·sina, taking the maximum of the two, then the magnitude of the balancing force F that the prestressed tendon 33 needs to provide is... N =T 水平 The cross-sectional area of ​​a single prestressed tendon 33 is A, as measured. P By selecting materials, the tension control stress of the prestressed tendon 33 is determined to be δ. Then, considering the reduction of prestress loss during actual operation, a coefficient λ is obtained. Therefore, the required number of prestressed tendons 33 is calculated. Workers can calculate the required force value of the prestressed tendons based on the load-bearing values, which facilitates the selection of materials for the prestressed tendons 33. This can effectively save costs while ensuring structural stability, and also allows for the use of appropriate materials in different situations.

[0042] The number of prestressed anchoring points is determined by the number n of prestressed beams 33, and the arrangement of the prestressed anchoring points should meet the tensioning space requirement of the prestressed beam 33. The size of the anchoring steel plate used and the position of the anchoring opening are determined according to the maximum horizontal cable force of the prestressed beam. The steel beam anchoring steel plate 31 is arranged on both sides of the cable anchorage plate 32 to ensure sufficient tensioning operation space for the prestressed beam 33, and workers can arrange the anchoring points calculated to speed up the construction progress while ensuring the stability of the structure and reducing the intensity of manual operation.

[0043] The prestressed beam 33 can be tensioned 1-4 times according to the structure stress condition to ensure good stress condition of the cable tower structure. Before the n-th tensioning of the cable, the maximum tension value of a single cable in the same side is T n ; and the tensioning force of a single low-retraction anchor 331 during tensioning of the prestressed beam is The prestress of the prestressed beam 33 can balance the horizontal component of the cable after this tensioning. Before the last tensioning of the cable, the tensioning control stress of a single low-retraction anchor 331 during tensioning of the prestressed beam 33 is The prestressed beam 33 is calculated to calculate the stress condition of the cable tower structure, further to ensure the stability of the cable tower, and also to analyze the use and service life of the structure under different tensions, which is convenient for further improvement of the structure.

[0044] The tensioning force of the prestressed beam 33 actively balances the horizontal component of the cable. By arranging the prestressed beam 33 near the anchoring area of the concrete tooth block 2, the passive increase in sectional resistance is changed to active reduction of the load bearing capacity of the anchoring area, so that the cable tower is in the best stress state, more stable and durable, and the service life of the structure is prolonged. By actively applying the balance force of the main and side span cable, the ring prestress of the concrete cable tower anchoring area can be completely cancelled.

[0045] Table 1: Stress calculation and analysis of MIDAS FEA three-dimensional entity modeling

[0046]

[0047] In combination Figure 2As shown in Table 1, the MIDAS FEA finite element is used to build a three-dimensional entity to calculate and analyze the stress of the entity of the application, and one segment of the upper tower column tooth block is selected for analysis; the concrete pylon and tooth block are stacked with C50 concrete, the elastic modulus is 34.5 GPa, the Poisson's ratio is 0.2, and only the elastic stage is considered; the top of the pylon is a free end, the concrete tower wall is extended downward by about 3 segment heights and the three horizontal translation degrees of freedom of the bottom surface are constrained, the pylon tower column and the tooth block are coupled, the cable and the prestress are loaded as a surface load. Among them, NB13 is the cable at the edge of the tooth block, and NZ13 is the cable at the middle position of the tooth block. Through the data in Table 1, the key components can be improved, the appropriate material is selected for stacking, which greatly enhances the reliability of the structure, auxiliary improves the design efficiency, and also reduces the use cost.

[0048] In combination Figure 3 and Figure 4 As shown, Figure 3 is a common tooth block structure, Figure 4 is the tooth block structure of the application, under the action of the same cable force, the maximum tensile stress generated by the cable force of the common tooth block structure on the tower wall is 2.18 Mpa, and the maximum tensile stress generated by the cable force of the tooth block structure of the application on the tower wall is 0.12 Mpa; the tensile stress generated by the tooth block structure of the application is much smaller than that generated by the common tooth block, and is in a safe state, which can realize the complete cancellation of the hoop prestress of the concrete pylon anchoring area, solve a series of problems such as main tower steel cutting, concrete vibration inconvenience, structure bearing capacity weakening and complex construction caused by the hoop prestress of the existing pylon tooth block anchoring area, reduce the construction cost, and further improve the safety and construction efficiency of the pylon structure.

[0049] Although embodiments of the application have been shown and described, it is to be understood that the application is not limited to the details of the foregoing embodiment, and that various changes in the form and details thereof can be made by those skilled in the art without departing from the spirit and scope of the application. The scope of the application is defined by the appended claims and their equivalents.

Claims

1. A design method of an actively balanced cable tower concrete tooth block anchoring structure, characterized by, The anchoring structure comprises a cable tower body, concrete tooth blocks and anchoring assemblies, the concrete tooth blocks are arranged on opposite sides of the inner wall of the cable tower body, and the anchoring assemblies are arranged on the two concrete tooth blocks; The design method comprises the following steps: (1) material calculation; the horizontal component force of the cable-stayed cable is calculated according to the design drawing to obtain the balance force provided by the prestressed beam, and the number of the prestressed beam required is obtained through the balance force, and the size of the anchoring steel plate and the anchoring opening position are obtained through the number of the prestressed force; (2) anchoring presetting; the cable-stayed cable anchor pad and the steel beam anchoring steel lug are prearranged on the concrete tooth block when the cable tower body and the concrete tooth block are poured, and the steel beam anchoring steel lug is arranged on both sides of the cable-stayed cable anchor pad; (3) prestressed beam installation and tensioning; when the concrete tooth block reaches the design strength, the prestressed beam is installed, and the prestressed beam is tensioned 1-4 times according to the structure stress condition, so as to ensure that the cable tower structure stress condition is good; The prestressed beam is composed of a plurality of low-retraction anchors, and the plurality of low-retraction anchors are arranged horizontally and spaced apart and connected to the steel beam anchoring steel lug at both ends.

2. The design method of the active balance type cable tower concrete tooth block anchoring structure according to claim 1, characterized in that, The inside of the concrete tooth block is provided with a plurality of steel bars, and the plurality of steel bars extend into the inside of the cable tower body.

3. The design method of the active balance type cable tower concrete tooth block anchoring structure according to claim 1, characterized in that, The calculation method of the cable-stayed cable horizontal component force, the prestressed beam balance force and the required number of prestressed beams in step (1) is: The cable tower body and the concrete tooth block correspond to the cable of the cable tower body top end to form a bridge cable force The vertical angle with the cable tower body top end The horizontal component force of the cable is calculated respectively The maximum value of the two is the size of the balance force provided by the prestressed beam According to the measurement, the cross-sectional area of a single low-retraction anchor is Through material selection, the tension control stress of the prestressed beam is According to the specification, the coefficient considering the prestress loss reduction is λ, so the number of the required prestressed beam is calculated .

4. The design method of the active balance type cable tower concrete tooth block anchoring structure according to claim 1, characterized in that, The calculation method of the size of the anchoring steel plate and the anchoring opening position through the number of the prestressed force in step (1) is: The number of prestressed anchoring points is determined by the number of the prestressed beam, the arrangement of the prestressed anchoring points should meet the space requirement of the prestressed beam tensioning, the size of the anchoring steel plate and the anchoring opening position used by the steel beam anchoring steel lug are determined according to the maximum horizontal cable force of the prestressed beam, and the steel beam anchoring steel lug is arranged on both sides of the cable-stayed cable anchor pad to ensure that the prestressed beam has enough tensioning operation space.

5. The design method of an actively balanced cable tower concrete tooth block anchorage structure according to claim 3, characterized in that, The multiple tension test method in step (3) is: The prestressed beam is tensioned according to the stress condition of the structure in 1-4 times, so as to ensure that the stress condition of the cable tower structure is good, and the maximum tension value of a single cable in the same side of the cable is taken as ; when the prestressed beam is tensioned, the tension of a single low-retraction anchor is , and the prestress of the prestressed beam can balance the horizontal component of the cable after the n-th tension, and the tension control stress of a single low-retraction anchor is when the prestressed beam is tensioned before the last tension of the cable.

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