Construction method of loose assembly of integral steel anchor beam on tower of single-tower cable-stayed bridge

Abstract

The present application discloses a method for assembling an integral steel anchor beam on a tower of a single-tower cable-stayed bridge, comprising the following steps: prefabricating a left module and a right module of the steel anchor beam, and prefabricating a steel bracket supporting the steel anchor beam; installing the steel bracket at the current installation position of the tower column; hoisting the left module and the right module at the current installation position; connecting the left module and the right module to form the steel anchor beam; allowing the steel anchor beam to fall onto the steel bracket and connect. The present application splits the integral steel anchor beam into four parts for prefabrication, and assembles them after hoisting them to the installation position, thereby reducing the load of each hoisting, achieving the construction requirements of small-scale transportation and the use of small hoisting equipment, and is suitable for construction areas with poor transportation and hoisting conditions.

Description

Technical Field

[0001] The present application relates to the field of cable-stayed bridge construction, and in particular to a method for loosely assembling an integral steel anchor beam tower of a single-tower cable-stayed bridge. Background Art

[0002] The integral steel anchor beam of the cable-stayed bridge generally adopts the construction method of integral lifting and segmented positioning and connection. Generally, for the installation process of the integral steel anchor beam on the tower column, it is necessary to use a positioning cradle or installation bracket to pre-assemble or pre-position the steel anchor beam and the steel corbel, or even to connect the steel anchor beam and the steel corbel and then lift the whole to the tower column for positioning and installation.

[0003] In South China and East China, when water transport conditions are available, the use of large-tonnage lifting tower cranes to hoist the steel anchor beam as a whole has the characteristics of simple construction, small factors affecting the quality of in-plant processing, and relatively short construction period. However, in mountainous areas such as southwest and northwest my country, where geological conditions such as crossing valleys are complex, transportation conditions are limited, and the existing tower cranes are insufficient in lifting weight, the method of hoisting and installing the steel anchor beam as a whole will increase the difficulty and cost of the project. Summary of the invention

[0004] The purpose of this application is to overcome the shortcomings of the prior art and provide a method for loosely assembling the tower of a single-tower cable-stayed bridge with an integral steel anchor beam that is suitable for situations where transportation conditions are poor and tower cranes are limited.

[0005] In order to achieve the above technical objectives, the technical solutions adopted in this application are as follows:

[0006] A method for loosely assembling an integral steel anchor beam tower of a single-tower cable-stayed bridge comprises the following steps:

[0007] prefabricating a left module and a right module of a steel anchor beam, and prefabricating a steel bracket supporting the steel anchor beam;

[0008] Installing the steel corbel at the current installation position of the tower column;

[0009] Hoisting the left module and the right module at the current installation position;

[0010] Connecting the left module and the right module to form the steel anchor beam;

[0011] The steel anchor beam is dropped onto the steel corbel and connected.

[0012] Specifically, the steel anchor beam is divided into the left module, the right module, and an installation interval between the left module and the right module along its longitudinal direction.

[0013] Furthermore, the left module and the right module are prefabricated and then hoisted to installation positions corresponding to the tower columns, and the installation intervals are assembled on-site at the installation positions.

[0014] Furthermore, the installation interval is defined by a process plate connecting the left module and the right module.

[0015] Optionally, before connecting the left module and the right module, a steel plate is padded at the weld to set a pre-camber.

[0016] Preferably, before hoisting the left module and the right module, the tower column positioning of the cable guide tube, the top plate elevation and theoretical anchor point of the corresponding steel bracket are measured to confirm the installation positions of the left module and the right module.

[0017] Further preferably, before the steel corbels are hoisted into place, the steel corbels installation base is measured and leveled with steel plates; after the steel corbels are hoisted into place, the steel corbels are fixed to the rigid frame of the tower column with angle steels.

[0018] Optionally, the method for hoisting the steel bracket includes:

[0019] A set of lifting holes is provided on the upper end of the wall plate of the steel corbel;

[0020] Use a sling to penetrate the hoisting hole to connect the steel corbel and the crane;

[0021] The hanger comprises a steel pipe passing through the hanging hole, a pair of steel plates clamping both ends of the steel pipe, ear plates connecting the tops of the pair of steel plates, and nuts locking the ends of the steel pipe.

[0022] Furthermore, before hoisting the left module and the right module at the current installation position, a steel anchor beam lifting system is arranged on the installed steel corbel.

[0023] Preferably, before the steel anchor beam is dropped onto the steel corbel, the edges of the steel anchor beam and the steel corbel are marked.

[0024] Further preferably, a steel anchor beam mounting bracket is installed at the current installation position of the tower column to position the steel corbel and the steel anchor beam.

[0025] Compared with the prior art, this application has the following advantages:

[0026] (1) The method of the present application separates the integral steel anchor beam into four parts for prefabrication, and assembles them after hoisting them to the installation location, thereby reducing the load of each hoisting and achieving the construction requirements of small-scale transportation and the use of small hoisting equipment;

[0027] (2) In the method of the present application, the steel anchor beam used has an increased installation interval, which is installed after the left module and the right module of the steel anchor beam are hoisted into place. On the one hand, it ensures the relative independence of the left module and the right module in terms of structural function, and on the other hand, it also maintains the structural integrity.

[0028] (3) In the method of the present application, the steel anchor beam is first jacked up and then dropped off the frame before being connected to the steel corbel. After jacking up, manual operation space for installing the installation interval is reserved, and the docking position between the steel anchor beam and the steel corbel can also be corrected, so that they can be accurately positioned after being dropped off the frame. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 The present invention is a construction flow chart of the loose assembly construction method of the integral steel anchor beam tower of the single-tower cable-stayed bridge for this application.

[0030] Figure 2 This is a schematic diagram of the structure of the steel anchor beam used in this application. DETAILED DESCRIPTION

[0031] The present application is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0032] refer to Figure 1 The single-tower cable-stayed bridge integral steel anchor beam tower loose assembly construction method of the present application comprises the following steps:

[0033] S1: prefabricate the left and right modules of the steel anchor beam, and prefabricate the steel brackets supporting the steel anchor beam. Figure 2 As shown, the steel anchor beam 1 of the present application is divided into a left module 11, a right module 12, and an installation interval 13 between the left module 11 and the right module 12 along its longitudinal direction. The left module 11 includes a bottom plate, two webs vertically connected to the bottom plate, and an anchoring portion arranged between the two webs; the structure of the right module 12 is mirror-symmetrical to the left module 11; the left module 11 and the right module 12 are transported to the construction site as a whole after being prefabricated in the factory and wait for hoisting in place. The installation interval 13 is defined by the process plate connecting the left module 11 and the right module 12. In a possible embodiment, the process plate includes a temporary code plate (not shown) connecting the bottom plate of the left module 11 and the bottom plate of the right module 12, and a plurality of connecting plates connecting the web of the left module 11 and the upper edge of the web of the right module 12. The plurality of connecting plates can prevent the overall deformation of the steel anchor beam 1 in terms of function, and can maintain consistency with the left module 11 and the right module 12 in terms of appearance. These process panels are assembled on site after the left module 11 and the right module 12 are initially positioned on the tower column.

[0034] The steel corbels are usually configured to include wall panels, upper decks, webs, sleeves, connection plates, flange plates, stiffening plates, shear nails, etc. The steel corbels are usually prefabricated in factories to ensure quality. However, when the cranes and conventional hoists used on site cannot properly hoist the steel corbels, the steel corbels and hoists are modified as follows:

[0035] A group of lifting holes are opened on the upper end of the wall panel of the steel corbel, and a lifting tool is used to penetrate the lifting holes to connect the steel corbel and the crane. In this embodiment, there are two lifting holes, and it is intended to use a two-point lifting method for lifting. However, the distance between the two lifting holes and the upper edge of the steel corbel wall panel is large, and the conventional simple clamp cannot meet the lifting requirements. Therefore, a special lifting tool is set up: including a steel pipe for penetrating the lifting holes, a pair of steel plates clamping the two ends of the steel pipe, ear plates connecting the top of the pair of steel plates, and nuts locking the ends of the steel pipes. A stiffening plate can also be added between the nut and the steel plate to prevent the steel plate and the steel pipe from deforming. The length of the pair of steel plates can be selected to suit the lifting size, and the lifting tool can be processed using materials on the construction site, which is easy to use.

[0036] The middle span and side span of a single-column cable-stayed bridge in a certain engineering project are of different lengths, making the entire bridge an asymmetric structure with the tower column as the center. Therefore, each steel anchor beam designed has a large-mileage anchorage part and a small-mileage anchorage part. When the steel anchor beam is in place at the installation position corresponding to the tower column, the corresponding anchorage part must be confirmed, and the large-mileage steel bracket and the small-mileage steel bracket are set according to the stress conditions of the steel anchor beam. When each steel bracket is in place at the installation position corresponding to the tower column, the corresponding correct steel bracket must also be confirmed.

[0037] S2: installing the steel bracket at the current installation position of the tower column;

[0038] In this embodiment, the steel anchor beam is installed as the tower column increases in height, and the tower column is divided into sections for installation of the rigid frame, steel bar binding and concrete pouring. For the current section, after the installation of the rigid frame is completed, the first steel anchor beam of the current section can be installed. The steel anchor beam is supported by the steel corbel, so the steel corbel at the current installation position is installed first.

[0039] Before the steel corbel is hoisted into place, the steel corbel installation base is measured and leveled with a steel plate; in order to improve the positioning accuracy, it is preferred to use a steel anchor beam installation bracket to assist the positioning of the steel corbel and the subsequent steel anchor beam, but in other embodiments, when the role of the steel anchor beam installation bracket can be omitted after the positioning method is improved, the steel anchor beam installation bracket is not a necessary structure. Further, the steel corbel needs to be installed according to the correspondence between the large mileage and the small mileage mentioned above.

[0040] After the steel corbels are hoisted into place, they are first temporarily fixed to the rigid frame, the center positions of the cable guide tubes entering and exiting the tower are checked, and the elevations of the top plates of the large and small mileage steel corbels are checked to see if they are in the same horizontal plane. Based on this, precise positioning is performed and the steel corbels are fixed to the rigid frame with L75 angle steels, thereby completing the precise positioning of the steel corbels.

[0041] S3: hoisting the left module and the right module at the current installation position;

[0042] In this embodiment, a steel anchor beam lifting system is arranged on the installed steel corbel, and the steel anchor beam lifting system includes four 32-ton jacks. The four jacks are controlled to lift synchronously, so that the steel anchor beam is lifted steadily before being formed into a whole, which is convenient for subsequent welding processes.

[0043] Furthermore, before hoisting the left module and the right module, it is necessary to measure the theoretical anchor points to confirm the installation positions of the left module and the right module, and retest is required after the left module and the right module are hoisted into place.

[0044] S4: Connect the left module and the right module to form the steel anchor beam;

[0045] Mark the edges of the steel anchor beam and the steel corbel to facilitate accurate positioning after lifting the steel anchor beam, insert a 3mm steel plate at the butt weld of the steel anchor beam to set the pre-arch; weld temporary code plates, set a code plate at both ends and in the middle of the left and right steel anchor beams and weld them to the steel anchor beam; weld the vertical and top connection plates; synchronously lift the steel anchor beam 50cm high through the aforementioned steel anchor beam Dingsheng system to facilitate the installation of ceramic linings for butt welds, weld grinding, flatness inspection, etc.; weld the butt welds of the bottom plates of the left and right steel anchor beams, weld other rib plates, inspect the welds, and grind the bottom surface of the welds after passing the test. The welding of temporary code plates and connection plates is mainly to ensure that the steel anchor beam does not deform after the lifting and subsequent welding of the bottom plate butt welds are completed.

[0046] S5: drop the steel anchor beam onto the steel corbel and connect them.

[0047] In this embodiment, the steel anchor beam and the steel corbel are precisely positioned according to the marking lines on the edges of the previously marked steel anchor beam and the steel corbel. After the steel anchor beam is precisely positioned on the steel corbel, the steel anchor beam and the steel corbel on the side span are fixed by three-sided circumferential welding, and the steel anchor beam and the steel corbel on the middle span are temporarily fixed by high-strength bolts, so as to facilitate the subsequent adjustment of the cable force of the inclined cable.

[0048] After the first steel anchor beam of each segment concrete is in place, the steel bars of the corresponding segment of the main tower can be tied. The second set of steel anchor beams in the segment and the main tower steel bars can be constructed simultaneously. The welding time of a single set of steel anchor beams is 2 to 2.5 days.

[0049] To summarize, the present application discloses a method for assembling the integral steel anchor beam on the tower of a single-tower cable-stayed bridge, in which the integral steel anchor beam is split into four parts for prefabrication, which are then assembled after being hoisted to the installation location, thereby reducing the load for each hoisting and achieving the construction requirements of small-scale transportation and the use of small hoisting equipment. The method is suitable for construction areas with poor transportation and hoisting conditions.

[0050] The above embodiments are preferred implementation modes of the present application, but are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present application should be equivalent replacement methods and are included in the protection scope of the present application.

Claims

1. A method for loosely assembling an integral steel anchor beam tower of a single-tower cable-stayed bridge, characterized in that: The steps include: prefabricating a left module and a right module of a steel anchor beam, and prefabricating a steel bracket supporting the steel anchor beam; Installing the steel corbel at the current installation position of the tower column; Hoisting the left module and the right module at the current installation position; Connecting the left module and the right module to form the steel anchor beam; The steel anchor beam is dropped onto the steel bracket and connected; The method for hoisting the steel bracket includes: Two lifting holes are provided on the upper end of the wall plate of the steel corbel; Use a sling to penetrate the hoisting hole to connect the steel corbel and the crane; The hanger includes a steel pipe passing through the lifting hole, a pair of steel plates clamping both ends of the steel pipe, ear plates connecting the tops of the pair of steel plates, and nuts locking the ends of the steel pipe; the length of the pair of steel plates is selected to adapt to the distance between the two lifting holes.

2. The method according to claim 1, characterized in that The steel anchor beam is divided into the left module, the right module, and an installation interval between the left module and the right module along its longitudinal direction.

3. The method according to claim 2, characterized in that The left module and the right module are prefabricated and then hoisted to the installation positions corresponding to the tower columns, and the installation intervals are assembled on-site at the installation positions.

4. The method according to claim 3, characterized in that The installation interval is defined by a process plate connecting the left module and the right module.

5. The method according to claim 3, characterized in that Before connecting the left module and the right module, a steel plate is inserted at the weld to set a pre-camber.

6. The method according to claim 1, characterized in that Before hoisting the left module and the right module, the tower column positioning of the cable guide tube, the top plate elevation and theoretical anchor point of the corresponding steel bracket are measured to confirm the installation positions of the left module and the right module.

7. The method according to claim 1, characterized in that Before the steel corbels are hoisted into place, the steel corbel installation foundation is measured and leveled using steel plates; after the steel corbels are hoisted into place, the steel corbels are fixed to the rigid frame of the tower column using angle steels.

8. The method according to claim 1, characterized in that Before hoisting the left module and the right module at the current installation position, a steel anchor beam lifting system is arranged on the installed steel corbel.

9. The method according to claim 8, characterized in that Before the steel anchor beam is dropped onto the steel corbel, the edges of the steel anchor beam and the steel corbel are marked.

10. The method according to claim 1, characterized in that A steel anchor beam mounting bracket is installed at the current installation position of the tower column to position the steel corbel and the steel anchor beam.

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