A main tower column using prestress as stress control and a construction method thereof

Abstract

A kind of main tower column using prestress as stress control, including tower bottom section, lower inclined section, upper inclined section and tower top section poured in turn from bottom to top, lower inclined section and upper inclined section are equipped with lower crossbeam, upper inclined section and tower top section are equipped with middle crossbeam, upper crossbeam is equipped in the middle of tower top section, and inclined cable is equipped on tower top section;The lower inclined section is inclinedly arranged on tower bottom section, and the lower inclined section includes two oppositely arranged lower pouring sections, and the lower pouring section is inclined outward from bottom to top;Compared with prior art, pre-tightening assembly and pre-support assembly are arranged on the upper and lower sides of tower limb section during tower column construction, and the prestress of pre-tightening assembly and pre-support assembly is tensioned, to realize the control of the inconsistent situation of internal and external compressive stress of tower column under the action of self weight, climbing formwork body and other temporary load, to ensure that tower column has better vertical line and stability during construction.

Description

Technical Field

[0001] This invention relates to the field of cable-stayed bridge main tower technology, specifically to a main tower column using prestress as stress control and its construction method. Background Technology

[0002] During the construction of the main tower of a concrete cable-stayed bridge, as the segmental construction of the main tower gradually begins, the axis of the main tower is not always perpendicular to the plane and remains vertical. The tower columns of the cable-stayed bridge begin to tilt outward or inward. In order to solve the problem of local stress in the tower columns exceeding the design specifications due to the tilting of the main tower columns, the common practice is to install tie rods and symmetrical struts. When the tower columns tilt outward, tie rods are set according to the tower column construction stage model, and the tension of the tie rods is determined by calculation to keep the compressive stress on the inner and outer sides of the tower columns within the design reserve range and not exceed the specified design value. When the tower columns tilt inward, struts are set according to the tower column construction stage model, and the support force of the struts is determined by calculation to keep the compressive stress on the inner and outer sides of the tower columns within the design reserve range and not exceed the specified design value.

[0003] This conventional approach requires the installation of steel supports and tie rods on the outside of the tower column. The welding and processing of components takes a long time, and the tower column partially obstructs the view, making subsequent dismantling difficult. Moreover, it requires working at height, which is dangerous.

[0004] Chinese Patent No. CN110184916A discloses a cable-stayed bridge main tower, comprising at least one anchorage segment, wherein the anchorage segment comprises multiple anchorage segments connected in sequence, each anchorage segment comprising: a first pressure-bearing shell having two sets of first cable-staying cable holes passing through both sides of the first pressure-bearing shell and located within a first reinforced concrete layer of the first pressure-bearing shell; further comprising two sets of first bending-resistant shells, both of which are steel shell structures, respectively located on both sides of the first pressure-bearing shell; and two sets of second cable-staying cable holes passing through the two sets of first bending-resistant shells, wherein the two sets of second cable-staying cable holes are matched with the two sets of first cable-staying cable holes.

[0005] The cable-stayed bridge main tower disclosed above is connected by multiple anchoring segments connected in sequence. However, during the construction process, the main tower column of the cable-stayed bridge begins to tilt outward or inward along the construction direction. The multiple anchoring segments connected in sequence may cause the local stress of the tower column to exceed the design specifications due to the tilting of the main tower column, which affects the processing accuracy and also poses certain safety hazards. Summary of the Invention

[0006] The present invention aims to overcome the defects in the prior art and provide a main tower column and its construction method that utilizes prestress as stress control to ensure consistent compressive stress on the inner and outer sides of the tower body, without the need for additional external tie rods and struts.

[0007] To achieve the aforementioned objectives, the present invention employs the following technical solution: a main tower column utilizing prestress as stress control, comprising a tower base section, a lower casting section, a lower crossbeam, an upper casting section, a middle crossbeam, and a tower top section, cast sequentially from bottom to top; the lower casting section is located on the tower base section and is composed of symmetrically arranged lower inclined sections, each lower inclined section being composed of several lower casting segments arranged sequentially from bottom to top, the lower casting segments inclined outwards from bottom to top; the upper casting section is... It is placed on the lower crossbeam, and the upper pouring section is composed of symmetrically arranged upper inclined sections. The upper inclined section is composed of several upper pouring segments arranged sequentially from bottom to top, and the upper pouring segments are inclined inward from bottom to top. The lower inclined section is provided with a lower prestressing component arranged along the length direction of the lower pouring section, and the upper pouring section is provided with an upper prestressing component arranged along the length direction of the upper pouring section. The lower prestressing component is arranged in segments from bottom to top, and the upper prestressing component is also arranged in segments from bottom to top.

[0008] As a preferred embodiment of the present invention, the lower inclined section is provided with lower prestressing components on both the inner and outer sides, and the lower prestressing components on the inner and outer sides gradually approach each other from bottom to top.

[0009] As a preferred embodiment of the present invention, upper prestressing components are provided on both the inner and outer sides of the upper inclined section, and the upper prestressing components on the inner and outer sides are arranged in parallel.

[0010] As a preferred embodiment of the present invention, upper prestressing components are provided on both the inner and outer sides of the upper inclined section, and the upper prestressing components on the inner and outer sides are arranged in parallel.

[0011] As a preferred embodiment of the present invention, the lower prestressed component is composed of several lower steel strands of different lengths, and the length of the several lower steel strands gradually increases from the outside to the inside.

[0012] As a preferred embodiment of the present invention, the bottom of several lower steel strands are pre-embedded in the bottom section of the tower, and the top of the longest lower steel strand is flush with the top of the uppermost lower cast-in-place segment.

[0013] As a preferred embodiment of the present invention, the tops of several lower steel strands are flush with the tops of the corresponding lower casting segments.

[0014] As a preferred embodiment of the present invention, the upper prestressed component is composed of several upper steel strands of different lengths, and the length of the several upper steel strands gradually increases from the outside to the inside.

[0015] As a preferred embodiment of the present invention, the bottom of several upper steel strands is flush with the bottom of the lowest upper casting segment, and the top of the longest upper steel strand is flush with the top of the highest upper casting segment.

[0016] As a preferred embodiment of the present invention, the tops of several upper steel strands are flush with the tops of the corresponding upper casting segments.

[0017] A construction method for a main tower column using prestressing as stress control includes the following steps: Step A: Draw the tower drawings according to actual needs, and divide the tower into several casting segments from bottom to top according to the tower height; Step B: Cast the bottom section of the tower. Cast several sections of the bottom section of the tower from bottom to top to form the bottom section of the tower. Embed the lower steel strands on the top section of the bottom section of the tower. Step C: Cast the lower casting section, casting the lower casting sections sequentially from bottom to top. After the lower casting section is completed, tension the corresponding lower steel strands of the lower casting section. After tensioning, cast the upper lower casting section. Step D: Cast the lower crossbeam. After all the lower casting segments have been cast and all the lower steel strands have been tensioned, cast the lower crossbeam. Step E: Cast the upper casting section. Cast the upper casting section sequentially from bottom to top on the lower crossbeam. After the upper casting section is cast, tension the corresponding lower steel strands of the upper casting section. After tensioning, cast the upper upper casting section of the upper layer. Step F: Cast the middle crossbeam and the top section of the tower. After all the upper casting sections are completed and all the upper steel strands are tensioned, cast the middle crossbeam and then cast the top section of the tower on the middle crossbeam.

[0018] Compared with the prior art, the beneficial effects of the present invention are: 1. The lower and upper inclined sections are divided into several casting segments that are poured sequentially from bottom to top. Steel strands are set in the lower and upper inclined sections respectively along the length of the lower and upper inclined sections. The tensioning of the steel strands is used to achieve the preload of the lower and upper inclined sections. 2. By setting steel strands of the same length as the pouring segments, the pre-tensioning force of the pouring segment can be applied in a timely manner after the corresponding pouring segment is poured. The multi-segment pre-tensioning of the pouring segments ensures that the pre-tensioning force of the lower or upper inclined segments can be adjusted in a timely manner to meet the construction requirements. Attached Figure Description

[0019] Figure 1 This is the front view of the present invention; Figure 2This is a side view of the present invention; Figure 3 This is a structural schematic diagram of the lower pouring section; Figure 4 This is a structural schematic diagram of the upper pouring section; Reference numerals: Tower base section 1, lower inclined section 2, lower inclined section 21, lower cast-in-place section 22, lower prestressed component 23, lower steel strand 24, upper inclined section 3, upper inclined section 31, upper cast-in-place section 32, upper prestressed component 33, upper steel strand 34, tower top section 4, lower crossbeam 5, middle crossbeam 6. Detailed Implementation

[0020] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0021] like Figure 1-4 As shown, a main tower column using prestressing as stress control includes a bottom section 1, a lower casting section 2, a lower crossbeam 5, an upper casting section 3, a middle crossbeam 6, and a top section 4, cast sequentially from bottom to top. The lower casting section 2 is located on the bottom section 1 and is composed of symmetrically arranged lower inclined sections 21. Each lower inclined section 21 is composed of several lower casting segments 22 arranged sequentially from bottom to top, with the lower casting segments 22 inclined outwards from bottom to top. The upper casting section 3 is located on the lower crossbeam 5, and the upper section... The casting section 3 is composed of symmetrically arranged upper inclined sections 31, which are composed of several upper casting segments 32 arranged sequentially from bottom to top. The upper casting segments 32 are inclined inward from bottom to top. The lower inclined section 21 is provided with a lower prestressing component 23 arranged along the length of the lower casting section, and the upper casting section is provided with an upper prestressing component 33 arranged along the length of the upper casting section. The lower prestressing component 23 is arranged in segments from bottom to top, and the upper prestressing component 33 is also arranged in segments from bottom to top.

[0022] The tower base section 1, lower casting section 2, lower crossbeam 5, upper casting section 3, middle crossbeam 6 and tower top section 4 are vertically arranged from bottom to top. The lower casting section 2 forms a V-shaped structure with an opening at the top and is arranged symmetrically along the center. The upper casting section 3 forms an inverted V-shaped structure with an opening at the bottom and is also arranged symmetrically along the center.

[0023] The lower inclined section 21 is provided with lower prestressing components 23 on both the inner and outer sides, and the lower prestressing components 23 on the inner and outer sides gradually approach each other from bottom to top. The lower prestressing components 23 are set along the width direction of the lower inclined section 21 and along the side length direction of the inner and outer sides. The size of the lower inclined section 21 gradually decreases from bottom to top. Under the action of the lower prestressing components 23 on the inner and outer sides, the prestress on the inner and outer sides of the lower inclined section 21 is tensioned and adjusted respectively, and the lower prestressing components 23 on the inner and outer sides are independent of each other.

[0024] Upper prestressing components 33 are provided on both the inner and outer sides of the upper inclined section 31, and the upper prestressing components 33 on the inner and outer sides are arranged in parallel. The upper prestressing components 33 are arranged along the width direction of the upper inclined section 31 and along the side length direction of the inner and outer sides. The dimensions of the upper inclined section 31 remain consistent from bottom to top. Under the action of the upper prestressing components 33 on the inner and outer sides, the prestress on the inner and outer sides of the upper inclined section 31 is tensioned and adjusted respectively, and the upper prestressing components 33 on the inner and outer sides are independent of each other.

[0025] The lower prestressed component 23 is composed of several lower steel strands 24 of different lengths, and the length of the lower steel strands 24 gradually increases from the outside to the inside. The number of lower steel strands 24 of different lengths in the lower prestressed component 23 is set according to the number of lower casting segments 22. A lower steel strand 24 of different length is provided in the lower casting segment 22 connected to the tower bottom segment 1. A lower steel strand 24 of different length is provided in the lower casting segment 22 above every two segments.

[0026] Several lower steel strands 24 are pre-embedded in the bottom section 1 of the tower, and the top of the longest lower steel strand 24 is flush with the top of the uppermost lower casting section 22. The tops of several lower steel strands 24 are flush with the tops of the corresponding lower casting sections 22.

[0027] Specifically, the lower steel strand 24 consists of 13 steel strands, including 7 middle steel strands, 2 outer steel strands, 2 second outer steel strands, and 2 second second outer steel strands. The bottoms of all 13 steel strands are pre-embedded in the tower bottom section 1, and the bottoms of the 13 steel strands are flush. The 7 middle steel strands are the longest, and their tops are flush with the top of the uppermost lower cast-in-place section 22. The 2 outer steel strands are of the same length, the 2 second outer steel strands are of the same length, and the 2 second second outer steel strands are of the same length. The outer steel strands, second outer steel strands, second second outer steel strands, and middle steel strands are arranged sequentially from the outside to the inside.

[0028] The lower casting segment 22 is divided into segments 14, 15, 16, 17, 18, 19, and 20 from bottom to top. The top of the outer steel strand is flush with the top of segment 14, the second outer steel strand is flush with the top of segment 16, the second outermost steel strand is flush with segment 18, and the middle steel strand is flush with the top of segment 20.

[0029] After processing segment #14, the prestress of segment #14 is adjusted by tensioning the outer steel strands. After processing segment #16, the prestress of segments #14, #15, and #16 is adjusted by tensioning the secondary outer steel strands. After processing segment #18, the prestress of segments #14, #15, #16, #17, and #18 is adjusted by tensioning the secondary outer steel strands. After processing segment #20, the prestress of the overall lower inclined segment 21 is adjusted by tensioning the middle steel strands.

[0030] The upper prestressed component 33 is composed of several upper steel strands 34 of different lengths, and the length of the upper steel strands 34 gradually increases from the outside to the inside. The number of upper steel strands 34 of different lengths in the upper prestressed component 33 is set according to the number of upper casting segments 32. Each upper casting segment 32 above every two segments is provided with a section of upper steel strand 34 of different lengths.

[0031] The bottom of several upper steel strands 34 is flush with the bottom of the lowest upper casting segment 32, and the top of the longest upper steel strand 34 is flush with the top of the highest upper casting segment 32. The tops of several upper steel strands 34 are flush with the tops of the corresponding upper casting segments 32.

[0032] Specifically, the upper steel strand 34 consists of 13 steel strands, including 9 middle steel strands, 2 outer steel strands, and 2 second outer steel strands. The bottoms of all 13 steel strands are flush with the bottom of the lowest upper casting segment 32. The 9 middle steel strands are the longest, and their tops are flush with the top of the highest upper casting segment 32. The 2 outer steel strands are of the same length, and the 2 second outer steel strands are of the same length. The outer steel strands, second outer steel strands, and middle steel strands are arranged sequentially from the outside to the inside.

[0033] The upper casting segment 32 is divided into segments 23#, 24#, 25#, 26#, 27# and 28# from bottom to top. The top of the outer steel strand is flush with the top of segment 24#, the second outer steel strand is flush with the top of segment 26#, and the middle steel strand is flush with the top of segment 28#.

[0034] After segment #24 is processed, the prestress of segments #23 and #24 is adjusted by tensioning the outer steel strands. After segment #26 is processed, the prestress of segments #23, #24, #25, and #26 is adjusted by tensioning the secondary outer steel strands. After segment #20 is processed, the prestress of the overall upper inclined segment 31 is adjusted by tensioning the middle steel strands.

[0035] A construction method for a main tower column using prestressing as stress control includes the following steps: Step A: Draw the tower drawings according to actual needs, and divide the tower into several casting segments from bottom to top according to the tower height. The number and size of the casting segments are set according to the actual tower height.

[0036] Step B: Cast the bottom section 1 of the tower. Cast each casting segment of the bottom section 1 from bottom to top to form the bottom section 1 of the tower. Embed the lower steel strand 24 on the casting segment at the top of the bottom section 1 of the tower.

[0037] Step C: Pour the lower pouring section 2, pour the lower pouring section 22 sequentially from bottom to top, and after the lower pouring section 22 is poured, tension the lower steel strand 24 corresponding to the lower pouring section 22. After tensioning, pour the upper lower pouring section 22.

[0038] After processing segment #14, the prestress of segment #14 is adjusted by tensioning the outer steel strands. After processing segment #16, the prestress of segments #14, #15, and #16 is adjusted by tensioning the secondary outer steel strands. After processing segment #18, the prestress of segments #14, #15, #16, #17, and #18 is adjusted by tensioning the secondary outer steel strands. After processing segment #20, the prestress of the overall lower inclined segment 21 is adjusted by tensioning the middle steel strands.

[0039] Step D: Cast the lower crossbeam 5. After all the lower casting segments 22 have been cast and all the lower steel strands 24 have been tensioned, cast the lower crossbeam 5.

[0040] Step E: Cast the upper casting section 3. Cast the upper casting section 32 sequentially from bottom to top on the lower crossbeam 5. After the upper casting section 32 is cast, tension the corresponding lower steel strand 24. After tensioning, cast the upper upper casting section 32.

[0041] After segment #24 is processed, the prestress of segments #23 and #24 is adjusted by tensioning the outer steel strands. After segment #26 is processed, the prestress of segments #23, #24, #25, and #26 is adjusted by tensioning the secondary outer steel strands. After segment #20 is processed, the prestress of the overall upper inclined segment 31 is adjusted by tensioning the middle steel strands.

[0042] Step F: Cast the middle crossbeam 6 and the tower top section 4. After all the upper casting sections 32 are cast and all the upper steel strands 34 are tensioned, cast the middle crossbeam 6 and cast the tower top section 4 on the middle crossbeam 6.

[0043] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention; therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

[0044] Although this document frequently uses reference numerals from the figures, such as: tower base section 1, lower inclined section 2, lower inclined section 21, lower cast-in-place section 22, lower prestressed component 23, lower steel strand 24, upper inclined section 3, upper inclined section 31, upper cast-in-place section 32, upper prestressed component 33, upper steel strand 34, tower top section 4, lower crossbeam 5, and middle crossbeam 6, the possibility of using other terms is not excluded. These terms are used merely for the convenience of describing and explaining the essence of the invention; interpreting them as any additional limitation would contradict the spirit of the invention.

Claims

1. A main tower column using prestress as stress control, comprising, from bottom to top, a bottom section (1), a lower casting section (2), a lower crossbeam (5), an upper casting section (3), a middle crossbeam (6), and a top section (4); characterized in that, The lower casting section (2) is located on the bottom section (1) of the tower, and the lower casting section (2) is composed of symmetrically arranged lower inclined sections (21). The lower inclined sections (21) are composed of several lower casting segments (22) arranged sequentially from bottom to top, and the lower casting segments (22) are inclined outward from bottom to top. The upper casting section (3) is located on the lower crossbeam (5), and the upper casting section (3) is composed of symmetrically arranged upper inclined sections (31), and the upper inclined sections are inclined outward from bottom to top. The segment (31) is composed of several upper casting segments (32) arranged sequentially from bottom to top, the upper casting segments (32) being inclined inward from bottom to top; the lower inclined segment (21) is provided with a lower prestressing component (23) arranged along the length of the lower casting segment, and the upper casting segment is provided with an upper prestressing component (33) arranged along the length of the upper casting segment; the lower prestressing component (23) is arranged in segments from bottom to top, and the upper prestressing component (32) is arranged in segments. 3) It is also set in segments from bottom to top; the lower prestressed component (23) is composed of several lower steel strands (24) of different lengths, and the length of the lower steel strands (24) gradually increases from the outside to the inside; the bottom of the lower steel strands (24) is embedded in the bottom section (1) of the tower, and the top of the longest lower steel strand (24) is flush with the top of the uppermost lower casting segment (22); the lower casting segment (22) is divided into several segments from bottom to top. The segments are provided with several steel strands that are flush with the top of the corresponding segments; the lower inclined segment (21) is provided with lower prestressing components (23) on both the inner and outer sides, and the lower prestressing components (23) on both the inner and outer sides gradually approach each other from bottom to top; the upper inclined segment (31) is provided with upper prestressing components (33) on both the inner and outer sides, and the upper prestressing components (33) on both the inner and outer sides are arranged in parallel, and the upper prestressing components (33) on both the inner and outer sides are independent of each other.

2. A main tower column using prestress as stress control according to claim 1, characterized in that, The tops of several lower steel strands (24) are flush with the tops of the corresponding lower cast-in-place segments (22).

3. A main tower column using prestress as stress control according to claim 1, characterized in that, The upper prestressed component (33) is composed of several upper steel strands (34) of different lengths, and the length of the several upper steel strands (34) gradually increases from the outside to the inside.

4. A main tower column using prestress as stress control according to claim 3, characterized in that, The bottom of several upper steel strands (34) is flush with the bottom of the lowest upper casting segment (32), and the top of the longest upper steel strand (34) is flush with the top of the highest upper casting segment (32).

5. A main tower column using prestress as stress control according to claim 4, characterized in that, The top of several upper steel strands (34) is flush with the top of the corresponding upper cast-in-place segment (32).

6. A construction method for a main tower column using prestressing as stress control, based on the main tower column using prestressing as stress control as described in any one of claims 1-5, characterized in that, Includes the following steps: Step A: Draw the tower drawings according to actual needs, and divide the tower into several casting segments from bottom to top according to the tower height; Step B: Cast the bottom section (1). Cast several casting sections of the bottom section (1) from bottom to top to form the bottom section (1). Embed the lower steel strand (24) on the casting section at the top of the bottom section (1). Step C: Cast the lower casting section (2), cast the lower casting segment (22) from bottom to top, and after the lower casting segment (22) is cast, tension the lower steel strand (24) corresponding to the lower casting segment (22), and after tensioning, cast the upper lower casting segment (22). Step D: Cast the lower crossbeam (5). After all the lower casting segments (22) have been cast and all the lower steel strands (24) have been tensioned, cast the lower crossbeam (5). Step E: Cast the upper casting section (3). Cast the upper casting section (32) sequentially from bottom to top on the lower crossbeam (5). After the upper casting section (32) is cast, tension the upper steel strand (34) corresponding to the upper casting section (32). After tensioning, cast the upper casting section (32) of the upper layer. Step F: Cast the middle crossbeam (6) and the tower top section (4). After all the upper casting sections (32) are cast and all the upper steel strands (34) are tensioned, cast the middle crossbeam (6) and cast the tower top section (4) on the middle crossbeam (6).

Images