Large-inclination cable tower tensile stress control method and tensile stress adjusting device construction method

Abstract

The invention discloses a large-inclination cable tower tensile stress control method which is used for regulating and controlling cable tower bottom tensile stress in real time and comprises the following steps that S1, a large-inclination cable tower comprises two symmetrically-arranged tower columns, and the two tower columns are constructed section by section at the same time; s2, the tower bottom tensile stress measured value of the large-inclination cable bent tower is detected in real time, and whether transverse supporting force needs to be applied between the two tower columns of the current section or not is judged according to the tower bottom tensile stress measured value; s3, if yes, skipping to execute the step S4; if not, skipping to execute the step S5; s4, calculating the size of the required transverse supporting force, carrying out transverse supporting between the two tower columns, and then skipping to execute the step S5; and S5, the next sections of the two tower columns continue to be built and constructed, the step S2 and the step S3 are executed again till construction of the large-inclination cable bent tower is completed, and all the transverse supporting force between the two tower columns is removed.

Description

Technical Field

[0001] The invention relates to the field of bridges, in particular to the field of cable tower construction of cable-stayed bridges, and to a tensile stress control method for a large-inclination cable tower and a tensile stress adjustment device construction method. Background Art

[0002] A cable-stayed bridge is a bridge structure consisting of a main beam, a cable tower, and cable stays. The cable stays connect the main beam to the cable tower, and the tension of the cable stays is used to support the main beam and share the load. The larger the span of a cable-stayed bridge, the higher the cable tower.

[0003] At present, between the cable towers on both sides of the common cable-stayed bridge, upper and lower beams are fixed near the top and bottom respectively. The lower beam is installed with a support to support the main beam. However, the structure of this cable tower is complex and requires precise design and construction. The connection between the lower beam and the cable tower needs to consider a variety of force conditions, including tension, pressure and bending moment. This requires the use of high-precision measurement and positioning equipment during the construction process to accurately control the structure, which increases the difficulty of controlling construction accuracy and scheduling construction processes. At the same time, it also prolongs the construction period and increases construction costs.

[0004] In order to improve the above situation, the following Figure 1 The cable tower structure shown does not have a lower crossbeam, and only has an upper crossbeam fixed to the top of the cable tower, which can effectively shorten the construction period.

[0005] In adopting Figure 1 When designing the cable tower structure shown in the figure, you may encounter a situation where you need to design the cable tower as a large-angle cable tower (the inclination angle of the cable tower relative to the vertical line exceeds 30°), for example, to adapt to the terrain, such as valleys and river bends, to reduce damage to the terrain; for example, to more effectively transfer loads and reduce the bending moment and shear force of the main beam to improve the overall efficiency of the structure; from the perspective of design aesthetics, choose a large-angle cable tower to increase the visual impact and artistic effect of the bridge, etc.

[0006] Then, during the construction of a large-inclination cable tower, due to the excessive inclination of the cable tower, the bottom of the cable tower column will have excessive tensile stress. If effective measures are not taken, it may affect the safety of the entire bridge structure.

[0007] It is necessary to improve the design for this situation in order to adjust the tensile stress at the bottom of the tower and improve the safety of the entire bridge structure without increasing the difficulty of construction and extending the construction period. Summary of the invention

[0008] The purpose of the present invention is to provide a method for controlling the tensile stress of a large-inclination cable tower and a method for constructing a tensile stress adjustment device, so as to solve the technical problem that when a large-inclination cable tower structure with only an upper crossbeam but no lower crossbeam is adopted, the tensile stress at the bottom of the tower is easily excessive due to the large inclination of the tower column, thereby affecting the safety of the entire bridge structure.

[0009] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0010] In a first aspect, the present invention discloses a method for controlling the tensile stress of a large-inclination tower, which is used to control the tensile stress of the bottom of the tower in real time, comprising the following steps:

[0011] S1. The steeply inclined cable tower includes two symmetrically arranged tower columns, which are constructed simultaneously and section by section.

[0012] S2, real-time detection of the measured value of the tensile stress at the bottom of the steeply inclined cable tower, and judging whether it is necessary to apply a lateral support force between two tower columns of the current segment according to the measured value of the tensile stress at the bottom of the tower;

[0013] S3, if necessary, jump to step S4; if not necessary, jump to step S5;

[0014] S4, calculating the required lateral support force, and performing lateral support between the two tower columns, and then jumping to step S5;

[0015] S5, continue to construct the next section of the two tower columns, and return to execute steps S2 and S3 until the construction of the large-angle cable tower is completed and all lateral support forces between the two tower columns are cancelled.

[0016] This solution can be applied to cable-stayed bridges with large inclination towers that only have upper crossbeams but no lower crossbeams. It can overcome the situation where the tensile stress at the bottom of the tower is too large due to the large inclination of the tower column. It can dynamically control the tensile stress at the bottom of the tower during the construction process and maintain the tensile stress at the bottom of the tower at a low level close to or equal to 0, thereby improving the safety of the bridge structure.

[0017] Preferably, in step S2, whether it is necessary to apply a lateral support force between two tower columns of the current segment is determined by the following method:

[0018] S2.1. Obtain the allowable tensile stress [σ] of the tower concrete;

[0019] S2.2. When it is determined that the measured value of the tensile stress σ at the bottom of the tower satisfies 0≤σ≤[σ] / 2, it is determined that a lateral support force needs to be applied between the two tower columns of the current segment.

[0020] Preferably, in step S4, the method for calculating the required lateral support force comprises the following steps:

[0021] S4.1. Establish a finite element model for segmental construction of large-inclination cable towers;

[0022] S4.2, construct a calculation formula for the lateral support force, and set the target tower bottom tensile stress value to 0;

[0023] S4.3, set the initial value F0 of the lateral support force, and substitute the initial value F0 of the lateral support force into the finite element model of the segmented construction of the high-inclination cable tower to simulate the tensile stress value δ1 at the bottom of the tower at this time;

[0024] S4.4, increase the initial value of the lateral support force F0, obtain the lateral support force adjustment value F′=F0+δ, and substitute the lateral support force adjustment value F′ into the finite element model of the segmented construction of the high-inclination cable tower to simulate the tower bottom tensile stress value δ2 at this time;

[0025] S4.5. Using the F0, δ1, and δ2 values ​​in step S4.3 and step S4.4, the required lateral support force is calculated according to the calculation formula for the lateral support force constructed in step S4.2.

[0026] Preferably, in step S4.2, the calculation formula for the magnitude of the lateral support force F is:

[0027] F = F0 + ΔF;

[0028] Among them, the solution equation of ΔF is:

[0029]

[0030] In the above formula, F0 is the initial value of the lateral support force; ΔF is the lateral support force value that needs to be increased when the target tower bottom tensile stress value is 0; δ1 is the tower bottom tensile stress value measured when the two tower columns are laterally supported according to the initial value of the lateral support force F0; 0 is the target tower bottom tensile stress value; δ is the lateral support force adjustment increment; δ2 is the tower bottom tensile stress value measured when the two tower columns are laterally supported according to the lateral support force adjustment value F′.

[0031] Preferably, in step S4, lateral support is provided between two tower columns by installing a tensile stress adjustment device, the two tower columns are respectively a first tower column and a second tower column, the tensile stress adjustment device comprises a steel pipe extending horizontally, one end of the steel pipe is fixed to the outer wall of the first tower column or the second tower column facing the opposite tower column, and a jack is fixed to the other end of the steel pipe, the jack can be extended and retracted horizontally, and when the jack is extended, it can provide a jacking force to the outer wall of the second tower column or the first tower column, thereby achieving lateral support between the two tower columns.

[0032] In order to make the tensile stress adjustment device more stably installed between the two towers, as a preferred solution of the tensile stress adjustment device, when the corresponding sections of the first tower and the second tower that need lateral support are constructed, the first embedded part and the second embedded part are symmetrically pre-embedded on the opposite sides of the first tower and the second tower in advance; the first embedded part and the second embedded part respectively include a first steel plate and a second steel plate, and the first steel plate and the second steel plate are respectively located on the outer side of the outer wall of the first tower and the second tower. When installing the steel pipe, first weld one end of the steel pipe to the first steel plate or the second steel plate, and then install a jack on the other end of the steel pipe.

[0033] In order to ensure that the threshold range of the thrust force adjustment can meet the requirements, as a preferred solution for the tensile stress adjustment device, the steel pipe includes a first steel pipe and a second steel pipe, the first steel pipe and the second steel pipe are arranged in parallel, one end of the first steel pipe and the second steel pipe are respectively welded and fixed to the first steel plate or the second steel plate, and the other end of the first steel pipe and the second steel pipe corresponds to the second steel plate or the first steel plate, and the first jack and the second jack are respectively installed between them.

[0034] During construction, the jacking force of the first jack and the second jack is adjusted according to the required lateral support force, so that the jacking force applied by the first jack and the second jack between the two tower columns is the same, and the sum of the jacking force of the first jack and the second jack is consistent with the required lateral support force.

[0035] In order to enable the tensile stress adjustment device to be installed more stably between the two tower columns, as a preferred solution for the tensile stress adjustment device, a first bracket and a second bracket are respectively installed on the side walls of the first tower column and the second tower column below the first embedded part and the second embedded part, and the first bracket and the second bracket can serve as installation platforms for the tensile stress adjustment device; a plurality of pads are placed between the bottoms of the first steel pipe and the second steel pipe and the first bracket and the second bracket respectively, and the height of each pad can be adjusted.

[0036] During the specific construction, the first bracket and the second bracket are installed first, and then the first steel pipe and the second steel pipe are hoisted onto the corresponding brackets in batches and installed in parallel. A plurality of pads with adjustable heights are used to support the first steel pipe and the second steel pipe. The height of each pad is adjusted so that the first steel pipe and the second steel pipe maintain a horizontal and laterally extended state, and the first jack and the second jack installed at the end can be supported within the range of the first steel plate or the second steel plate, thereby optimizing the stress condition of the first tower column or the second tower column when subjected to the top thrust, and making the stress more uniform and stable.

[0037] Preferably, a first flat bracket and a second flat bracket are fixed between the first steel pipe and the second steel pipe respectively, and the purpose of the first flat bracket and the second flat bracket is to increase the integrity of the first steel pipe and the second steel pipe and ensure the safety of the device.

[0038] In a second aspect, the present invention further discloses a construction method of a tensile stress adjustment device, using the tensile stress adjustment device as described above, comprising the following steps:

[0039] A1. When it is determined that a lateral support force needs to be applied between the two tower columns of the current segment, the first embedded part and the second embedded part are symmetrically pre-embedded on opposite sides of the first tower column and the second tower column in advance during the construction of the current segment, to ensure that the first steel plate and the second steel plate are respectively located outside the outer walls of the first tower column and the second tower column;

[0040] A2. Install the first bracket and the second bracket on the side walls of the first tower column and the second tower column below the first embedded part and the second embedded part respectively, and evenly place a plurality of pads on the upper surfaces of the first bracket and the second bracket;

[0041] A3. Lift the first steel pipe and the second steel pipe onto the bracket in batches, and install them in parallel, and adjust the height of each cushion block so that the first steel pipe and the second steel pipe remain in a horizontally extended state;

[0042] A4. Weld one end of the first steel pipe and the second steel pipe to the first steel plate or the second steel plate respectively, install the first jack and the second jack to the other end of the first steel pipe and the second steel pipe respectively, and support the first jack and the second jack on the second steel plate or the first steel plate;

[0043] A5. According to the required lateral support force, adjust the thrust of the first jack and the second jack so that the thrust applied between the two towers by the first jack and the second jack is consistent with the required lateral support force;

[0044] A6. Continue to construct the next section of the two tower columns;

[0045] A7. Repeat steps A1 to A6 until the construction of the steep-angle cable tower is completed, and remove all tensile stress adjustment devices installed between the two tower columns.

[0046] The present invention has the following beneficial effects: the present invention can be applied to a cable-stayed bridge with a large inclination tower which is only provided with an upper crossbeam but not a lower crossbeam, and can solve the technical problem that the large inclination of the tower column of the tower easily causes excessive tensile stress at the bottom of the tower, thereby affecting the safety of the entire bridge structure, and avoids the situation in which the tensile stress at the bottom of the tower is excessive due to the large inclination of the tower column of the tower, and can dynamically control the tensile stress at the bottom of the tower during the construction process, maintain the tensile stress at the bottom of the tower at a low level close to or equal to 0, thereby improving the safety of the bridge structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] In order to make the purpose, technical solution and advantages of the invention more clear, the present invention will be further described in detail below with reference to the accompanying drawings, in which:

[0048] Figure 1 It is a schematic diagram of the cable tower structure of a cable-stayed bridge in the prior art.

[0049] Figure 2 The present invention is a schematic diagram of the structure of a large-angle cable tower of a cable-stayed bridge without a lower crossbeam.

[0050] Figure 3 It is a structural schematic diagram of the tensile stress adjustment device of the present invention.

[0051] Figure 4 for Figure 3 Center A view.

[0052] Figure 5 for Figure 4 Center B view.

[0053] Figure 6 It is a finite element model of segmented construction of a large-inclination cable tower established in an embodiment of the present invention.

[0054] Figure 7 It is a schematic diagram of the finite element simulation of the tensile stress of the tower when the large-angle tower tensile stress control method is not used to perform real-time regulation of the tensile stress at the bottom of the tower in an embodiment of the present invention.

[0055] Figure 8 It is a schematic diagram of the finite element verification results after the tensile stress of the bottom of the tower is controlled in real time by using the large-angle tower tensile stress control method in an embodiment of the present invention.

[0056] Explanation of the reference numerals: 101, first tower column; 102, second tower column; 103, upper crossbeam; 104, first support; 105, second support; 200, tensile stress adjustment device; 201, steel pipe; 202, jack; 203, cushion block; 204, first steel pipe; 205, second steel pipe; 206, first horizontal bracket; 207, second horizontal bracket; 301, first embedded part; 302, second embedded part; 303, first steel plate; 304, second steel plate; 305, first bracket; 306, second bracket. DETAILED DESCRIPTION

[0057] To make the purpose, technical solution and advantages of the embodiments of the present invention more clear, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0058] It should be noted that similar numbers and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further defined and explained in the subsequent drawings. In the description of the present invention, it should be noted that the orientation or position relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inside", "outside", etc. is based on the orientation or position relationship shown in the drawings, or the orientation or position relationship in which the invention product is usually placed when used, which is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present invention. In addition, the terms "first", "second", "third", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance. In addition, the terms "horizontal", "vertical", etc. do not mean that the components are absolutely horizontal or suspended, but can be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "vertical", and does not mean that the structure must be completely horizontal, but can be slightly tilted. In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0059] The present invention can be applied to the field of cable tower construction of cable-stayed bridges, and solves the technical problem that when a large-inclination cable tower structure with only an upper crossbeam but no lower crossbeam is adopted, the large inclination of the tower column of the cable tower may easily cause excessive tensile stress at the bottom of the tower, thereby affecting the safety of the entire bridge structure.

[0060] It should be noted that the large-angle cable tower described in this application refers to a cable tower structure in which the inclination angle of a single-side tower column exceeds 30° relative to the vertical line.

[0061] Based on the technical problems solved above, the present invention discloses a method for controlling the tensile stress of a large-inclination cable tower, which is used to control the tensile stress of the bottom of the cable tower in real time, comprising the following steps:

[0062] S1. The steeply inclined cable tower includes two symmetrically arranged tower columns, which are constructed simultaneously and section by section.

[0063] S2, real-time detection of the measured value of the tensile stress at the bottom of the steeply inclined cable tower, and judging whether it is necessary to apply a lateral support force between two tower columns of the current segment according to the measured value of the tensile stress at the bottom of the tower;

[0064] S3, if necessary, jump to step S4; if not necessary, jump to step S5;

[0065] S4, calculating the required lateral support force, and performing lateral support between the two tower columns, and then jumping to step S5;

[0066] S5, continue to construct the next section of the two tower columns, and return to execute steps S2 and S3 until the construction of the large-angle cable tower is completed and all lateral support forces between the two tower columns are cancelled.

[0067] The present invention can be applied to a cable-stayed bridge with a large inclination tower which is only provided with an upper crossbeam but not a lower crossbeam, and can solve the technical problem that the large inclination of the tower column of the tower easily causes excessive tensile stress at the bottom of the tower, thereby affecting the safety of the entire bridge structure, and avoids the situation where the tensile stress at the bottom of the tower is excessive due to the large inclination of the tower column of the tower. The tensile stress at the bottom of the tower can be dynamically controlled during the construction process, and the tensile stress at the bottom of the tower can be maintained at a low level close to or equal to 0, thereby improving the safety of the bridge structure.

[0068] Preferably, in step S2, whether it is necessary to apply a lateral support force between two tower columns of the current segment is determined by the following method:

[0069] S2.1. Obtain the allowable tensile stress [σ] of the tower concrete;

[0070] S2.2. When it is determined that the measured value of the tensile stress σ at the bottom of the tower satisfies 0≤σ≤[σ] / 2, it is determined that a lateral support force needs to be applied between the two tower columns of the current segment.

[0071] Specifically, in step S2.1, [σ] is the allowable tensile stress of the tower concrete, which can be found in the specification.

[0072] Preferably, in step S4, the method for calculating the required lateral support force comprises the following steps:

[0073] S4.1. Establish a finite element model for segmental construction of large-inclination cable towers;

[0074] S4.2, construct a calculation formula for the lateral support force, and set the target tower bottom tensile stress value to 0;

[0075] S4.3, set the initial value F0 of the lateral support force, and substitute the initial value F0 of the lateral support force into the finite element model of the segmented construction of the high-inclination cable tower to simulate the tensile stress value δ1 at the bottom of the tower at this time;

[0076] S4.4, increase the initial value of the lateral support force F0, obtain the lateral support force adjustment value F′=F0+δ, and substitute the lateral support force adjustment value F′ into the finite element model of the segmented construction of the high-inclination cable tower to simulate the tower bottom tensile stress value δ2 at this time;

[0077] S4.5. Using the F0, δ1, and δ2 values ​​in step S4.3 and step S4.4, the required lateral support force is calculated according to the calculation formula for the lateral support force constructed in step S4.2.

[0078] Preferably, in step S4.2, the calculation formula for the magnitude of the lateral support force F is:

[0079] F=F0+ΔF (1)

[0080] Among them, the solution equation of ΔF is:

[0081]

[0082] In formula (1) and formula (2), F0 is the initial value of the lateral support force; ΔF is the lateral support force value that needs to be increased when the target tower bottom tensile stress value is 0; δ1 is the tower bottom tensile stress value measured when the two tower columns are laterally supported according to the initial value of the lateral support force F0; 0 is the target tower bottom tensile stress value; δ is the lateral support force adjustment increment; δ2 is the tower bottom tensile stress value measured when the two tower columns are laterally supported according to the lateral support force adjustment value F′.

[0083] As a preference, see Figure 2 and Figure 3 In step S4, a tensile stress adjustment device 200 is installed between two tower columns for lateral support. The two tower columns are a first tower column 101 and a second tower column 102. The tensile stress adjustment device

[0084] 200 includes a steel pipe 201 extending horizontally, one end of the steel pipe 201 is fixed to the outer wall of the first tower column 101 or the second tower column 102 facing the opposite tower column, and the other end of the steel pipe 201 is fixed with a jack 202, and the jack 202 can be extended and retracted horizontally. When the jack 202 is extended, it can provide a thrust to the outer wall of the second tower column 102 or the first tower column 101, thereby realizing lateral support between the two tower columns.

[0085] In order to make the tensile stress adjustment device 200 be more stably installed between the two towers, as a preferred solution of the tensile stress adjustment device 200, please refer to Figure 3When the corresponding sections of the first tower column 101 and the second tower column 102 that need to be supported laterally are constructed, the first embedded parts 301 and the second embedded parts 302 are symmetrically embedded in advance on the opposite sides of the first tower column 101 and the second tower column 102; the first embedded parts 301 and the second embedded parts 302 respectively include the first steel plate 303 and the second steel plate 304, which are respectively located outside the outer walls of the first tower column 101 and the second tower column 102. When installing the steel pipe 201, one end of the steel pipe 201 is first welded and fixed to the first steel plate 303 or the second steel plate 304, and then the jack 202 is installed on the other end of the steel pipe 201.

[0086] In order to ensure that the thrust force adjustment threshold range can meet the requirements, please refer to Figure 3 As a preferred solution of the tensile stress adjustment device 200, the steel pipe 201 includes a first steel pipe 204 and a second steel pipe 205, the first steel pipe 204 and the second steel pipe 205 are arranged in parallel, one end of the first steel pipe 204 and the second steel pipe 205 are respectively welded and fixed to the first steel plate 303 or the second steel plate 304, and the other end of the first steel pipe 204 and the second steel pipe 205 is respectively installed with the first jack 202 and the second jack 202 between the corresponding second steel plate 304 or the first steel plate 303. During construction, according to the required lateral support force, the jacking force of the first jack 202 and the second jack 202 is adjusted, so that the jacking force applied by the first jack 202 and the second jack 202 between the two towers is the same, and the sum of the jacking force of the first jack 202 and the second jack 202 is consistent with the required lateral support force.

[0087] In order to make the tensile stress adjustment device 200 more stably installed between the two towers, please refer to Figure 3As a preferred solution of the tensile stress adjustment device 200, a first bracket 305 and a second bracket 306 are respectively installed on the side walls of the first tower column 101 and the second tower column 102 below the first embedded part 301 and the second embedded part 302, and the first bracket 305 and the second bracket 306 can serve as installation platforms for the tensile stress adjustment device 200; a plurality of cushion blocks 203 are respectively placed between the bottom of the first steel pipe 204 and the second steel pipe 205 and the first bracket 305 and the second bracket 306, and the height of each cushion block 203 can be adjusted. During the specific construction, the first bracket 305 and the second bracket 306 are installed first, and then the first steel pipe 204 and the second steel pipe 205 are hoisted onto the corresponding brackets in batches and installed in parallel. A plurality of height-adjustable pads 203 are used to support the first steel pipe 204 and the second steel pipe 205. The height of each pad 203 is adjusted so that the first steel pipe 204 and the second steel pipe 205 maintain a horizontal and transversely extended state, and the first jack 202 and the second jack 202 installed at the end can be supported within the range of the first steel plate 303 or the second steel plate 304, thereby optimizing the stress condition of the first tower column 101 or the second tower column 102 when subjected to the top thrust, and making the stress more uniform and stable.

[0088] For details, please refer to Figure 3 Before installing the first bracket 305 and the second bracket 306, it is also necessary to embed a plurality of bracket embedded parts in the first tower column 101 and the second tower column 102 corresponding to the force support points of each bracket, and each bracket embedded part is exposed on the surface of the first tower column 101 and the second tower column 102. Each bracket embedded part serves as an attachment point for the first bracket 305 and the second bracket 306. The first bracket 305 and the second bracket 306 are respectively welded to the surfaces of the corresponding bracket embedded parts to provide a construction platform and a force-bearing platform for the first steel pipe 204 and the second steel pipe 205.

[0089] In addition, using the tensile stress adjustment device 200 as described above, the present invention also discloses a construction method of the tensile stress adjustment device 200, comprising the following steps:

[0090] A1. When it is determined that a lateral support force needs to be applied between the two tower columns of the current section, the first embedded part 301 and the second embedded part 302 are symmetrically pre-embedded on the opposite sides of the first tower column 101 and the second tower column 102 in advance during the construction of the current section, ensuring that the first steel plate 303 and the second steel plate 304 are respectively located outside the outer walls of the first tower column 101 and the second tower column 102;

[0091] A2. Install the first bracket 305 and the second bracket 306 on the side walls of the first tower column 101 and the second tower column 102 below the first embedded part 301 and the second embedded part 302, respectively, and evenly place a plurality of cushion blocks 203 on the upper surfaces of the first bracket 305 and the second bracket 306;

[0092] A3. Lift the first steel pipe 204 and the second steel pipe 205 onto the bracket in batches, and install them in parallel, and adjust the height of each cushion block 203 so that the first steel pipe 204 and the second steel pipe 205 maintain a horizontal and transversely extended state;

[0093] A4. Weld one end of the first steel pipe 204 and the second steel pipe 205 to the first steel plate 303 or the second steel plate 304, respectively, install the first jack 202 and the second jack 202 to the other end of the first steel pipe 204 and the second steel pipe 205, respectively, and support the first jack 202 and the second jack 202 on the second steel plate 304 or the first steel plate 303;

[0094] A5. According to the required lateral support force, adjust the jacking force of the first jack 202 and the second jack 202 so that the jacking force applied between the two tower columns by the first jack 202 and the second jack 202 is consistent with the required lateral support force;

[0095] A6. Continue to construct the next section of the two tower columns;

[0096] A7. Repeat steps A1 to A6 until the construction of the steep-angle cable tower is completed, and remove all tensile stress adjustment devices 200 installed between the two tower columns.

[0097] As a preference, see Figure 4 and Figure 5 A first flat bracket 206 and a second flat bracket 207 are fixed between the first steel pipe 204 and the second steel pipe 205, respectively. The first flat bracket 206 and the second flat bracket 207 are arranged in parallel; both sides of the first flat bracket 206 are fixed to the first steel pipe 204 and the second steel pipe 205 near the top, respectively, and both sides of the second flat bracket 207 are fixed to the first steel pipe 204 and the second steel pipe 205 near the bottom; the purpose of the first flat bracket 206 and the second flat bracket 207 is to increase the integrity of the first steel pipe 204 and the second steel pipe 205 and ensure the safety of the device.

[0098] The large-angle cable tower tensile stress control method disclosed in the present invention has the following technical effects:

[0099] 1. The present invention can be applied to a cable-stayed bridge with a large inclination tower which is only provided with an upper crossbeam but not a lower crossbeam, and can solve the technical problem that the large inclination of the tower column of the tower easily causes excessive tensile stress at the bottom of the tower, thereby affecting the safety of the entire bridge structure, and avoids the situation where the tensile stress at the bottom of the tower is excessive due to the large inclination of the tower column of the tower. The tensile stress at the bottom of the tower can be dynamically controlled during the construction process, and the tensile stress at the bottom of the tower can be maintained at a low level close to or equal to 0, thereby improving the safety of the bridge structure.

[0100] 2. The method for quickly calculating the required lateral support force proposed in the present invention has a simple formula and utilizes the constructed finite element model of segmented construction of large-angle cable towers to quickly and accurately obtain the actual required lateral support force. The method is simple and clear, and has the characteristics of being fast and highly accurate. The result feedback can be flexibly and quickly performed at the construction site without affecting the construction progress and quality.

[0101] 3. The tensile stress control device of the present invention adopts steel pipes and jacks, and utilizes a simple structure to assist in realizing the dynamic regulation of the tensile stress at the bottom of the tower, and utilizes a parallel pipe to strengthen the integrity of the tensile stress control device to ensure the safety and reliability of the device.

[0102] Example

[0103] In order to further illustrate the method of the present invention, the present invention discloses the following application examples. This example takes the cable tower of the Dongying Yellow River Bridge as an example. Figure 2 The cable tower is a high-inclination cable tower, and has no lower crossbeam. The top of the cable tower is connected only by an upper crossbeam. According to the high-inclination cable tower tensile stress control method disclosed in the present invention, the tensile stress at the bottom of the cable tower is controlled in real time, including the following steps:

[0104] D1. The high-inclination cable tower includes two symmetrically arranged tower columns, namely the first tower column and the second tower column. The two tower columns are constructed simultaneously and section by section.

[0105] D2. Real-time detection of the measured value of the tensile stress at the bottom of the steeply inclined cable tower, and judging whether it is necessary to apply a lateral support force between the two tower columns of the current segment according to the measured value of the tensile stress at the bottom of the tower, specifically using the following method: first, obtaining the allowable tensile stress [σ] of the cable tower concrete. In this embodiment, the cable tower adopts C55 concrete, and the corresponding allowable tensile stress [σ] of the cable tower concrete is 1.8 MPa; then, when it is judged that the measured value of the tensile stress at the bottom of the tower σ satisfies 0≤σ≤[σ] / 2, that is, when 0≤σ≤0.9 MPa, it is judged that a lateral support force needs to be applied between the two tower columns of the current segment;

[0106] D3, if necessary, jump to step D4; if not necessary, jump to step D5;

[0107] In this embodiment, it is monitored that when the construction reaches the fifth section, the tensile stress σ at the bottom of the tower is 0.1Mpa, which meets the condition of 0≤σ≤0.9Mpa, and then the process jumps to step D4;

[0108] D4, calculate the required lateral support force, and provide lateral support between the two tower columns, then jump to step D5;

[0109] Specifically, the method for calculating the required lateral support force includes the following steps:

[0110] D4.1. Establish the finite element model for the segmental construction of the high-inclination cable tower. Figure 6 ;

[0111] D4.2, using the calculation formula of the lateral support force, i.e., formula (1) and formula (2), and setting the target tower bottom tensile stress value to 0;

[0112] D4.3. Set the initial value of the lateral support force F0 = 100KN, and substitute the initial value of the lateral support force F0 into the finite element model of the segmented construction of the high-inclination cable tower to simulate the tensile stress value δ1 = 0.09MPa at the bottom of the tower at this time;

[0113] D4.4. Increase the initial value of the lateral support force F0 to obtain the lateral support force adjustment value

[0114] F′=F0+δ=(100+100)KN, and according to the lateral support force adjustment value F′, the finite element model of the segmented construction of the high-inclination cable tower is substituted to simulate the tensile stress value δ2=0.06Mpa at the bottom of the tower at this time;

[0115] D4.5. Substitute the F0, δ1, and δ2 values ​​in steps D4.3 and D4.4 into equations (2) and (1) respectively, that is,

[0116] can be We get ΔF=300KN, and then F=F0+ΔF=100+300=400KN. At this time, we determine that the required lateral support force F of the current segment is 400KN.

[0117] This result is verified by substituting it into the finite element model. Figure 8 , we can see that the tensile stress at the bottom of the tower returns to zero. Figure 7 , which is the tensile stress condition of the tower when the large-angle tower tensile stress control method disclosed in the present invention is not used to perform real-time regulation on the tensile stress at the bottom of the tower. After the tower construction is completed, the tensile stress at the bottom of the tower is 6MPa, which is far more than 1.8Mpa.

[0118] D5. Continue to construct the next segment of the two tower columns, and return to execute steps D2 and D3 until the construction of the high-angle cable tower is completed and all lateral support forces between the two tower columns are cancelled.

[0119] In this example, see Figures 3 to 5 , a tensile stress adjustment device 200 is installed between the two tower columns for lateral support, wherein the tensile stress adjustment device 200 comprises a first steel pipe 204 and a second steel pipe 205 extending horizontally and arranged in parallel. In this embodiment, the outer diameters of the first steel pipe 204 and the second steel pipe 205 are both 630 mm, and the wall thicknesses are both 10 mm;

[0120] A first parallel bracket 206 and a second parallel bracket 207 are fixed between the first steel pipe 204 and the second steel pipe 205, respectively. Both are made of a steel pipe 201 with an outer diameter of 100 and a wall thickness of 8 mm according to the structure in the figure. The first parallel bracket 206 and the second parallel bracket 207 are used to increase the integrity of the first steel pipe 204 and the second steel pipe 205 to ensure the safety of the device.

[0121] One end of the first steel pipe 204 and the second steel pipe 205 are respectively welded and fixed to the first steel plate 303 or the second steel plate 304, and the other end of the first steel pipe 204 and the second steel pipe 205 are respectively installed with the first jack 202 and the second jack 202 between the second steel plate 304 or the first steel plate 303; the first jack 202 and the second jack 202 can be stretched and retracted horizontally at the same time, and when the first jack 202 and the second jack 202 are extended, they can provide a thrust to the outer wall of the second tower column 102 or the first tower column 101, thereby realizing lateral support between the two tower columns. During construction, according to the required lateral support force, the thrust of the first jack 202 and the second jack 202 is adjusted, so that the thrust applied by the first jack 202 and the second jack 202 between the two tower columns is the same, and the sum of the thrusts of the first jack 202 and the second jack 202 is consistent with the required lateral support force.

[0122] In order to enable the tensile stress adjustment device 200 to be installed more stably between the two tower columns, when the corresponding sections of the first tower column 101 and the second tower column 102 that need lateral support are constructed, the first embedded parts 301 and the second embedded parts 302 are symmetrically pre-embedded on the opposite sides of the first tower column 101 and the second tower column 102 in advance; the first embedded parts 301 and the second embedded parts 302 respectively include the first steel plate 303 and the second steel plate 304, and the first steel plate 303 and the second steel plate 304 are respectively located on the outer sides of the outer walls of the first tower column 101 and the second tower column 102.

[0123] In order to enable the tensile stress adjustment device 200 to be installed more stably between the two tower columns, a first bracket 305 and a second bracket 306 are respectively installed on the side walls of the first tower column 101 and the second tower column 102 below the first embedded parts 301 and the second embedded parts 302, and the first bracket 305 and the second bracket 306 can be used as installation platforms for the tensile stress adjustment device 200; a plurality of cushion blocks 203 are respectively placed between the bottom of the first steel pipe 204 and the second steel pipe 205 and the first bracket 305 and the second bracket 306, and the height of each cushion block 203 can be adjusted.

[0124] During the specific construction, the first bracket 305 and the second bracket 306 are installed first, and then the first steel pipe 204 and the second steel pipe 205 are hoisted onto the corresponding brackets in batches and installed in parallel. A plurality of height-adjustable pads 203 are used to support the first steel pipe 204 and the second steel pipe 205. The height of each pad 203 is adjusted so that the first steel pipe 204 and the second steel pipe 205 maintain a horizontal and transversely extended state, and the first jack 202 and the second jack 202 installed at the end can be supported within the range of the first steel plate 303 or the second steel plate 304, thereby optimizing the stress condition of the first tower column 101 or the second tower column 102 when subjected to the top thrust, and making the stress more uniform and stable.

[0125] Specifically, before installing the first bracket 305 and the second bracket 306, it is also necessary to pre-embed a plurality of bracket embedded parts in the first tower column 101 and the second tower column 102 corresponding to the force support points of each bracket, and each bracket embedded part is exposed on the surface of the first tower column 101 and the second tower column 102. Each bracket embedded part serves as an attachment point for the first bracket 305 and the second bracket 306. The first bracket 305 and the second bracket 306 are respectively welded to the surfaces of the corresponding bracket embedded parts to provide a construction platform and a force-bearing platform for the first steel pipe 204 and the second steel pipe 205.

[0126] The construction process of the tensile stress adjustment device of this embodiment is:

[0127] (1) When it is determined that a lateral support force needs to be applied between the two tower columns of the current section, the first embedded part 301 and the second embedded part 302 are symmetrically pre-embedded on the opposite sides of the first tower column 101 and the second tower column 102 in advance during the construction of the current section, ensuring that the first steel plate 303 and the second steel plate 304 are respectively located outside the outer walls of the first tower column 101 and the second tower column 102;

[0128] (2) The first bracket 305 and the second bracket 306 are respectively installed on the side walls of the first tower column 101 and the second tower column 102 below the first embedded part 301 and the second embedded part 302, and a plurality of cushion blocks 203 are evenly placed on the upper surfaces of the first bracket 305 and the second bracket 306;

[0129] (3) The first steel pipe 204 and the second steel pipe 205 are hoisted onto the bracket in batches and installed in parallel, and the first horizontal bracket 206 and the second horizontal bracket 207 are respectively fixed between the first steel pipe 204 and the second steel pipe 205, and the height of each cushion block 203 is adjusted so that the first steel pipe 204 and the second steel pipe 205 maintain a horizontally extended state;

[0130] (4) Weld one end of the first steel pipe 204 and the second steel pipe 205 to the first steel plate 303 or the second steel plate 304, respectively, install the first jack 202 and the second jack 202 to the other end of the first steel pipe 204 and the second steel pipe 205, respectively, and support the first jack 202 and the second jack 202 on the second steel plate 304 or the first steel plate 303;

[0131] (5) According to the required lateral support force, adjust the thrust of the first jack 202 and the second jack 202 so that the thrust applied between the two tower columns by the first jack 202 and the second jack 202 is consistent with the required lateral support force;

[0132] (6) Continue to construct the next section of the two tower columns;

[0133] (7) Repeat steps (1) to (6) until the construction of the steep-angle cable tower is completed, and remove all tensile stress adjustment devices 200 installed between the two tower columns.

[0134] It is understood that the present invention is described by some embodiments, and those skilled in the art are aware that various changes or equivalent substitutions may be made to these features and embodiments without departing from the spirit and scope of the present invention. Under the teachings of the present invention, these features and embodiments may be modified to adapt to specific circumstances and materials without departing from the spirit and scope of the present invention. The embodiments described in the present invention are part of the embodiments of the present invention, rather than all of the embodiments. The components of the embodiments of the present invention generally described and shown in the drawings herein may be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed herein, and all other embodiments obtained by ordinary technicians in the art without creative work based on the embodiments in the present invention belong to the scope of protection of the present invention.

Claims

1. A method for controlling the tensile stress of a large-inclination cable tower, which is used to control the tensile stress at the bottom of the cable tower in real time, characterized in that: The following steps are involved: S1. The steeply inclined cable tower includes two symmetrically arranged tower columns, which are constructed simultaneously and section by section. S2. Real-time detection of the measured value of the tensile stress at the bottom of the steeply inclined cable tower, and judging whether it is necessary to apply a lateral support force between two tower columns of the current segment according to the measured value of the tensile stress at the bottom of the tower; S3, if necessary, jump to step S4; if not necessary, jump to step S5; S4, calculating the required lateral support force, and performing lateral support between the two tower columns, and then jumping to step S5; S5, continue to construct the next section of the two tower columns, and return to execute steps S2 and S3 until the construction of the large-angle cable tower is completed and all lateral support forces between the two tower columns are cancelled.

2. The method for controlling tensile stress of a high-inclination cable tower according to claim 1, characterized in that: In step S2, whether it is necessary to apply a lateral support force between two tower columns in the current segment is determined by the following method: S2.

1. Obtain the allowable tensile stress [σ] of the tower concrete; S2.

2. When the measured value σ of the tensile stress at the bottom of the tower satisfies 0≤σ≤[σ] / 2, it is determined that a lateral support force needs to be applied between the two tower columns of the current segment.

3. The method for controlling tensile stress of a high-inclination cable tower according to claim 1, characterized in that: In step S4, the method for calculating the required lateral support force includes the following steps: S4.

1. Establish a finite element model for segmental construction of large-inclination cable towers; S4.2, construct a calculation formula for the lateral support force, and set the target tower bottom tensile stress value to 0; S4.3, set the initial value of the lateral support force F0, and substitute the initial value of the lateral support force F0 into the finite element model of the segmented construction of the high-inclination cable tower to simulate the tensile stress value δ1 at the bottom of the tower at this time; S4.4, increase the initial value of the lateral support force F0, obtain the lateral support force adjustment value F′=F0+δ, and substitute the lateral support force adjustment value F′ into the finite element model of the segmented construction of the high-inclination cable tower to simulate the tower bottom tensile stress value δ2 at this time; S4.

5. Using the F0, δ1, and δ2 values ​​in step S4.3 and step S4.4, the required lateral support force is calculated according to the calculation formula for the lateral support force constructed in step S4.

2.

4. The method for controlling the tensile stress of a high-inclination cable tower according to claim 3, characterized in that: In step S4.2, the calculation formula for the lateral support force F is: F = F0 + ΔF; Among them, the solution equation of ΔF is: In the above formula, F0 is the initial value of the lateral support force; ΔF is the lateral support force value that needs to be increased when the target tower bottom tensile stress value is 0; δ1 is the tower bottom tensile stress value measured when the two tower columns are laterally supported according to the initial value of the lateral support force F0; 0 is the target tower bottom tensile stress value; δ is the lateral support force adjustment increment; δ2 is the tower bottom tensile stress value measured when the two tower columns are laterally supported according to the lateral support force adjustment value F′.

5. The method for controlling tensile stress of a high-inclination cable tower according to any one of claims 1 to 4, characterized in that: In step S4, a tensile stress adjustment device is installed between two tower columns for lateral support, the two tower columns are respectively a first tower column and a second tower column, the tensile stress adjustment device comprises a steel pipe extending in a horizontal lateral direction, one end of the steel pipe is fixed to the outer wall of the first tower column or the second tower column facing the opposite tower column, and a jack is fixed to the other end of the steel pipe, the jack can be extended and retracted in a horizontal lateral direction, and when the jack is extended, it can provide a jacking force to the outer wall of the second tower column or the first tower column, thereby achieving lateral support between the two tower columns.

6. The method for controlling tensile stress of a high-inclination cable tower according to claim 5, characterized in that: When constructing the corresponding sections of the first tower column and the second tower column that require lateral support, the first embedded part and the second embedded part are symmetrically pre-embedded on opposite sides of the first tower column and the second tower column in advance; the first embedded part and the second embedded part include a first steel plate and a second steel plate, respectively, and the first steel plate and the second steel plate are respectively located on the outer sides of the outer walls of the first tower column and the second tower column.

7. The method for controlling tensile stress of a high-inclination cable tower according to claim 6, characterized in that: The steel pipe includes a first steel pipe and a second steel pipe, the first steel pipe and the second steel pipe are arranged in parallel, one end of the first steel pipe and the second steel pipe are respectively welded and fixed to the first steel plate or the second steel plate, and the other end of the first steel pipe and the second steel pipe corresponds to the second steel plate or the first steel plate, and the first jack and the second jack are respectively installed between them.

8. The method for controlling tensile stress of a high-inclination cable tower according to claim 7, characterized in that: The first bracket and the second bracket are respectively installed on the side walls of the first tower column and the second tower column below the first embedded part and the second embedded part; a plurality of pads are respectively placed between the bottom of the first steel pipe and the second steel pipe and the first bracket and the second bracket, and the height of each pad can be adjusted.

9. The method for controlling tensile stress of a high-inclination cable tower according to claim 8, characterized in that: A first parallel bracket and a second parallel bracket are fixed between the first steel pipe and the second steel pipe, respectively.

10. A method for constructing a tensile stress adjustment device, using the tensile stress adjustment device according to claim 8, characterized in that: The following steps are involved: A1. When it is determined that a lateral support force needs to be applied between the two tower columns of the current segment, the first embedded part and the second embedded part are symmetrically pre-embedded on opposite sides of the first tower column and the second tower column in advance during the construction of the current segment, to ensure that the first steel plate and the second steel plate are respectively located outside the outer walls of the first tower column and the second tower column; A2. Install the first bracket and the second bracket on the side walls of the first tower column and the second tower column below the first embedded part and the second embedded part respectively, and evenly place a plurality of pads on the upper surfaces of the first bracket and the second bracket; A3. Lift the first steel pipe and the second steel pipe onto the bracket in batches, and install them in parallel, and adjust the height of each cushion block so that the first steel pipe and the second steel pipe remain in a horizontally extended state; A4. Weld one end of the first steel pipe and the second steel pipe to the first steel plate or the second steel plate respectively, install the first jack and the second jack to the other end of the first steel pipe and the second steel pipe respectively, and support the first jack and the second jack on the second steel plate or the first steel plate; A5. According to the required lateral support force, adjust the thrust of the first jack and the second jack so that the thrust applied between the two towers by the first jack and the second jack is consistent with the required lateral support force; A6. Continue to construct the next section of the two tower columns; A7. Repeat steps A1 to A6 until the construction of the steep-angle cable tower is completed, and remove all tensile stress adjustment devices installed between the two tower columns.

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