WO2023213068A1 - Hoisting method for entire large diameter variable circular cross section steel bar segment - Google Patents

Abstract

A hoisting method for an entire large diameter variable circular cross section steel bar segment (1), where an adjustable disc-shaped lifting tool (2) is utilized, and shape and deformation characteristics of the large-diameter variable circular cross section steel bar segment (1) are sensibly taken into account; first, arced section main steel bars having lower deformation are connected, and after most of the stress of a main lifting hook is unloaded, the form of the steel bar segment (1) is restored, and then connection to main steels bars having greater linear section deformation is performed. By this means, no other measures for reducing deformation when hoisting the entire steel bar segment (1) are necessary, material is saved, and the speed of connecting steel bars is increased.

Description

Overall hoisting method for large diameter rounded section steel bar segments Technical field

This application relates to the field of bridge construction, and in particular to a method for integrally hoisting large-diameter rounded-section steel bar segments.

Background technique

The hoisting of large-diameter steel bar segments requires controlling the deformation amplitude of the steel bar after lifting. It is easier to control the deformation degree of steel bar segments with a centrally symmetrical cross-section through existing technology, but for large-diameter steel bar segments with a non-centrally symmetrical cross-sectional shape It is difficult to control the deformation of steel bar segments after lifting, mainly because the deformation characteristics and deformation amount of steel bar segments with larger diameters and non-center symmetrical cross-sectional shapes when hoisted as a whole are different from the conventional situation. Currently, the existing In the overall hoisting process of steel bar segments, there is no overall hoisting method and corresponding special hoisting tools for large diameter rounded (elliptical) cross-section tower (pier) body segments with a diameter of 9-18m. If the steel bar segments are installed according to conventional construction methods, When setting up internal bracing structures or reinforcing ring supports, due to the large cross-section size of the steel bar segments, the deformation improvement effect is poor, resulting in a low pass rate of the steel bar protective layer, and the total hoisting weight is increased, making the connection between steel bar segments difficult and affecting the construction efficiency. .

Contents of the invention

The purpose of this application is to at least partially improve the shortcomings of the existing technology and provide an easy-to-operate and effective method for integrally hoisting large-diameter rounded cross-section steel bar segments.

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

An overall hoisting method for large-diameter rounded-section steel bar segments, which includes the following steps:

Bind the steel bar segments according to the preset rounded cross-section profile;

Set lifting points and connect corresponding lifting devices according to the deformation of the steel bar segments after lifting;

Use the hoisting device to hoist the steel bar segments as a whole to the docking position;

After docking the first main bar at the arc section, unload the spreader for the first time;

After docking the second main reinforcement at the straight section, evacuate the spreader.

Preferably, the binding of steel bar segments according to a preset rounded cross-sectional profile includes:

Pre-positioning tooth plates according to the docking requirements of the top and bottom openings of the steel bar segments;

Use the positioning tooth plate to tie the steel bar segments;

Wherein, the steel bar segments include a stiff frame, most of the main bars and stirrups connecting the main bars.

Further, after the spreader is evacuated, the binding of the remaining steel bars is completed.

Optionally, the hanging points are configured to be non-coplanar to adapt to the deformation of the steel bar segments.

Further optionally, the hanging points are arranged on the main ribs.

In a possible implementation, the spreader includes a coplanar upper structure and a non-coplanar lower structure. The lower structure includes a number of movable hangers suspended below the upper structure. The movable hangers correspond to the hanging points.

Optionally, the movable hanger is connected to the upper structure through an adjustable connecting piece for adjusting the height and plane position of the movable hanger.

Further, the first unloading of the spreader includes: unloading a load of 60% to 85% of the total load.

Compared with the existing technology, this application has the following advantages:

(1) The method of this application makes reasonable use of the shape and deformation characteristics of the large-diameter rounded cross-section steel bar segments. First, connect the main bars of the arc segments with smaller deformation, and then unload most of the stress on the main hook, allowing the steel bar segments to Restore the shape, and then connect the main bars at the straight line section with large deformation. In this way, there is no need to take other deformation measures to reduce the overall hoisting of the steel segment, such as adding reinforcing rings or increasing the stiffness of the rigid frame to increase the overall hoisting. Weight measures, saving materials and speeding up the connection of steel bars.

(2) The method of this application uses prefabricated positioning tooth plates to tie steel bar segments, which can accurately control the steel bar segments with variable cross-sections, reduce human errors, and improve construction quality.

(3) The spreader used in the method of this application has a double-layer structure. The upper structure is stable and the lower structure is adjustable. It can adapt to the calculated deformation of the cross section of the steel bar section to accurately determine the position and height of the lifting point. The adjustment effectively improves the overall lifting deformation of large-diameter rounded-section steel bar segments.

Description of the drawings

Figure 1 is a schematic cross-sectional view of a steel bar segment applicable to the embodiment of the present application.

Figure 2 is a schematic top structural view of an embodiment of the adjustable disc-shaped spreader of the present application.

Figure 3 is a schematic side structural view of an embodiment of the adjustable disc-shaped spreader of the present application.

Figure 4 is a schematic structural diagram of the movable hanger in the embodiment of the present application.

Figure 5 is a schematic side structural view of Figure 4.

Figure 6 is a schematic structural diagram of the first movable hanger of the present application.

Figure 7 is a schematic structural diagram of the second movable hanger of the present application.

Figure 8 is a physical diagram of the positioning tooth plate of this application.

Figure 9 is an on-site view of the aerial suspension state of the large-diameter rounded-section steel bar segments of this application being hoisted as a whole.

Detailed ways

The present application will be described in further detail below in conjunction with the accompanying drawings and specific embodiments.

The cross-section of a cable tower in a certain bridge project changes from a circular cross-section to a circular cross-section and then back to a circular cross-section from bottom to top, and the overall radial size of the cable tower changes from large to small and then to large, so the different characteristics of the cable tower The assembly height corresponds to the size and shape of the different steel bar segments. Among them, the deformation of the overall hoisting of the rounded cross-section steel bar segments is particularly prominent, which is mainly reflected in the large flexibility of a single steel bar. Due to the large diameter of the spliced steel cage, the overall stiffness of the steel bar segments cannot be significantly improved by forming a three-dimensional structure. Reinforcement, and the rounded cross-section steel bar segment has an arc segment curve and an arc-shaped top and bottom plane. After lifting the steel bar segment as a whole without setting up additional reinforcing structures, the arc segment The deformation amplitude of the top and bottom openings increases, which increases the difficulty of docking the upper and lower steel bar segments after the overall hoisting. Therefore, this application designs an overall hoisting method and an adjustable disc-shaped hoist 2 for use in view of the deformation of large-diameter rounded-section steel bar segments. This application is suitable for the overall hoisting process of large-diameter rounded-section steel bar segments.

Referring to Figure 1, the "large diameter" referred to in the embodiment of the present application refers to the situation where the widest point of the steel bar section cross-section reaches more than 9m, and "rounding" means that the steel bar section cross-section includes a circular part. The steel segment section includes two arc segments and two straight line segments connecting the end points of different arc segments. The steel bar segment 1 shown in Figure 1 is a hollow structure, so the main bars of the steel bar segment 1 are configured as an outer ring structure 1a and an inner ring structure 1b.

Referring to Figures 2 and 3, this application provides an adjustable disc-shaped spreader 2, including a main load-bearing rod 21, a connecting rod 22, a distribution beam 23 and a movable hanger 24. details as follows:

The main load-bearing rods 21 extend radially based on the center point, and each of the main load-bearing rods 21 is distributed in a disc shape on the same plane; the contact rod 22 connects the adjacent main load-bearing rods 21. The main load-bearing rod 21 and the contact rod 22 are connected by welding to form a non-detachable stable structure. Preferably, the main load-bearing rods 21 are evenly distributed on the plane, and several contact rods 22 are arranged from the edge of the main load-bearing rod 21 to the center point. Preferably, the radial spacing of each contact rod 22 is the same. In a possible implementation, the adjustable disc-shaped spreader 2 of the present application is provided with eight main load-bearing rods 21, and four contact rods 22 are provided between each two main load-bearing rods 21. The adjacent ones with the same distance from the center point The connecting rod 22 intersects at the same point on the main load-bearing rod 21. The main load-bearing rod 21 and the connecting rod 22 form a uniform spider web-like structure, or a uniform disk-like structure. The lifting points directly connected to the lifting equipment, according to the force The balance requirements are distributed on the main load-bearing rod 21, and the spreader 2 of the present application and the lifting equipment are connected through wire ropes (as shown in Figure 9). To adapt to the overall hoisting of the aforementioned steel bar segment 1, the radial length of the main load-bearing rod 21 needs to cover the largest and widest steel bar segment. Assuming that the rounded cross-section steel bar segment 1 is the largest steel bar segment, the main load-bearing rod 21 needs to cover the largest and widest steel bar segment. The length of 21 should be greater than the longest distance from the aforementioned center point (also the center point of steel bar segment 1) to the arc segment of steel bar segment 1. The radial spacing of the connecting rods 22 is suitable so that the inner ring structure 1b and the outer ring structure 1a fall under the projection of the spacing respectively, so as to avoid blocking the position where the main bar is provided in the steel bar segment 1 and affecting the subsequent setting of the movable hanger 24. . Furthermore, the main load-bearing rod 21 and the connecting rod 22 can be made of I-beam steel, and the specific model should be determined according to the load requirements.

The distribution beam 23 is fixed above the connecting rod 22 and spans at least two of the connecting rods 22 . The distribution beam 23 and the contact rod 22 are connected in the form of bolts, that is, the connection between the distribution beam 23 and the contact rod 22 is detachable. When in use, the distribution beam 23 can be configured as needed, and the distribution beam 23 can be increased where the load is greater. configuration, or reduce the configuration at a place where the load is small, or adjust the specific connection position of the distribution beam 23, which is not limited to the position shown in the figure. In this embodiment, adapted to the inner ring structure 1b and outer ring structure 1a of the steel bar segment 1, the length of the distribution beam 23 should cover the top of the inner ring structure 1b and the outer ring structure 1a. At this time, the distribution beam 23 is horizontal Three continuous connecting rods 22 are spanned. Correspondingly, the connecting rods 22 that support the distribution beam 23, especially the connecting rods 22 that support the distribution beam 23 with a movable hanger 24, need to be structurally reinforced at the supporting locations, such as It is to set up the stiffening plate. The distribution beam 23 is preferably made of I-beam steel, and the specific model should be determined according to the load requirements.

The movable hanger 24 is sleeved on the main load-bearing rod 21 and/or the distribution beam 23 , and is suspended below the main load-bearing rod 21 . Specifically, as shown in Figures 4 to 7, the movable hanger 24 includes a steel pipe 241 for casing steel bars, a clamp 244 for clamping a single steel bar, a lifting eye 243 extending from the steel pipe 241, and a sleeve. Rope loops 245 provided on the main load-bearing rod 21 and/or the distribution beam 23, and adjustable connectors 246 connecting the rope loops 245 and lifting lugs 243.

The steel pipe 241 body is provided with positioning holes 2411 for steel bars to penetrate. Each steel pipe 241 may have more than one positioning hole 2411, preferably two or three. The spacing of the positioning holes 2411 on the same steel pipe 241 is adapted. Regarding the spacing of the steel bars of the structure that needs to be hoisted, the size of the positioning holes 2411 should also be adapted to the type of steel bars of the structure that needs to be hoisted. In the spreader of the present application, the steel bars that penetrate the positioning holes 2411 are essentially the main bars of the steel bar segment 1. After the main bars penetrate the steel pipe 241, the top of each main bar is clamped by a drogue clamp, so that the drogue clamp is against The steel pipe 241 thus becomes a lifting point for the steel bar segment 1 . Preferably, the steel pipe 241 is a square steel pipe, thereby providing a top plane to abut against the taper sleeve clamp to increase the stress-bearing area. The taper sleeve clamp includes a taper sleeve and a clip that are nested with each other, and a gasket packed between the taper sleeve and the square steel pipe.

The embodiment of the present application provides two types of movable hangers. The main difference is that the number of steel pipes 241 is different. The first movable hanger 24a shown in Figure 6 contains two or more steel pipes 241; Each steel pipe 241 is arranged in parallel according to a preset spacing, and a pair of support steel plates 242 is provided to intersect with the steel pipe 241. At this time, at least a pair of lifting lugs 243 extend from the support steel plate 242, and a pair of lifting lugs 243 can pass through. The adjusting connector 246 is connected to a rope ring 245 to realize the installation with the main load-bearing rod 21 or the distribution beam 23 . The first movable hanger 24a of this embodiment is provided with three steel pipes 241. Each steel pipe 241 is provided with three positioning holes 2411. A pair of support steel plates 242 are connected at both ends of the steel pipe 241. The support steel plates 242 are provided with two For the lifting lugs 243, the hole axes of the two pairs of lifting lugs 243 are parallel to the axis of the steel pipe 241, so the first movable hanger 24a uses two rope rings 245 correspondingly. The first movable hanger 24a simultaneously clamps nine main bars. These nine main bars form a hanging point and are mainly used in the outer ring structure 1a of the steel bar segment 1 in this embodiment.

The second movable hanger 24b shown in Figure 7 contains one of the steel pipes 241. At this time, a pair of lifting lugs 243 are provided extending from the body of the steel pipe 241. The pair of lifting lugs 243 are connected to each other through an adjustable connector 246. The rope loop 245 can be connected to the main load-bearing rod 21 or the distribution beam 23 . The steel pipe 241 of the second movable hanger 24b of this embodiment has three positioning holes 2411. A pair of lifting lugs 243 extend from the middle of the steel pipe 241 body. The hole axes of the pair of lifting lugs 243 are parallel to the axis of the steel pipe 241. , so the second movable hanger 24b uses a rope ring 245 correspondingly. The second movable hanger 24b simultaneously clamps three main bars. These three main bars form a hanging point and are mainly used in the inner ring structure 1b of the steel bar segment 1 in this embodiment.

As shown in Figures 4 and 5, the rope ring 245 is directly sleeved on the main load-bearing rod 21 or the distribution beam 23. The position of the rope ring 245 is set with a limiting groove 25 to prevent the rope ring 245 from sliding and shifting. Alternatively, a pair of steel bar heads can be temporarily fixed on the top surface of the main load-bearing rod 21 or the distribution beam 23 to form the limiting groove 25 . Further, the position where the rope loop 245 is set is provided with a protective structure that disperses pressure and buffers. One possible implementation is to lay wooden boards 26 on the sides of the main load-bearing rod 21 and the distribution beam 23, and the wooden boards 26 pass through the main load-bearing rod 21 or The tie rod 27 of the distribution beam 23 body is fixed. When the main load-bearing rod 21 and the distribution beam 23 are made of I-beam, the wooden board 26 and the beam body cannot fit firmly, so the space between the wooden board 26 and the beam body is filled with square wood 28. To achieve support for plank 26. Further preferably, rubber 29 is sleeved on the upper and lower end surfaces of the main load-bearing rod 21 and the distribution beam 23. A 2cm thick rubber skin can be used. The wooden board 26 and the rubber 29 fully protect the surfaces of the main load-bearing rod 21 and the distribution beam 23, preventing the tension and friction generated by the rope ring 245 during the hoisting process from adversely affecting the main load-bearing rod 21 and the distribution beam 23. In addition, the loss of The wooden board 26 and the rubber skin are easy to replace, saving costs.

The rope loop 245 of the present application can be made of steel wire rope, and the length of the rope loop 245 should be adjusted according to the height of the hanging point. The adjustable connector of this application adopts a flower basket screw, a hand chain hoist, or other connecting devices that can adjust the length of the body longitudinally. The rope loop 245 can be used with the adjustable connector to easily adjust the height of the lifting point. Before lifting the steel bar segment 1, the length of the rope loop 245 can be selected and the installation length of the adjustable connector can be set. When the steel bar segment 1 is lifted, After being in the air and when docking in place, only adjusting the adjustable connector can realize instant adjustment of the height of the lifting point or the force balance of the lifting point to control the lifting posture of the steel bar segment 1.

It can be seen from this that the adjustable disc-shaped spreader 2 of the present application has a double-layer structure: an upper structure composed of a main load-bearing rod 21, a connecting rod 22 and a distribution beam 23, and a lower structure composed of a movable hanger 24. The upper structure is stable, and the lower structure is adjustable, which can adapt to the calculated deformation of each cross section of steel segment 1 to accurately adjust the position and height of the lifting point, effectively improving the deformation of the overall lifting of large diameter rounded section steel segments. Condition.

Further, the adjustable disc-shaped spreader 2 is used to realize the overall hoisting of large-diameter rounded cross-section steel bar segments. The specific method is as follows:

S1, tie the steel bar segments according to the preset rounded cross-section profile.

The lashing of steel bar segments is usually arranged at the lashing platform. At the bottom position of the steel bar segment of the lashing platform, a prefabricated positioning tooth plate (as shown in Figure 8) is placed. The positioning tooth plate is CNC cut to conform to each steel bar section. Requirements for the joint between the top and bottom of the section, especially the requirements for the inclination of the main reinforcement when binding. The positioning tooth plate defines the spacing and inclination angle at the bottom of each main bar through each positioning hole to accurately match the top of the butt steel segment. Use the positioning tooth plate to bind the steel bar segments. The steel bar segments that are bound at the binding platform include the rigid skeleton, most of the main bars and the stirrups connecting the main bars. If necessary, some tie bars are also included. The remaining small amount of steel bars are placed on the binding platform. Install in situ after alignment connection.

S2: Set the lifting point and connect the corresponding lifting device according to the deformation of the steel bar segment after lifting.

Calculation shows that when the large-diameter rounded cross-section steel bar segment of this embodiment is lifted in a conventional manner, its own weight will cause an increase in the deformation of the first main bar 11 of the circular arc segment, and the deformation situation is also different from the conventional situation. Therefore, It is necessary to increase the lifting stability of the arc segment and control the deformation after lifting. One of the control methods is to increase the lifting points. Another optional control method is to increase the lifting area of a single lifting point. In addition, for the outer ring structure 1a with dense main ribs in the embodiment of the present application, it is also necessary to set a denser tensile force to control the amount of deformation. Therefore, the aforementioned adjustable disc-shaped hanger 2 is used to set lifting points on the steel bar segments according to the predicted deformation of the large-diameter rounded cross-section. Specifically, the position of the connecting movable hanger 24 is determined at the steel bar segment. The first movable hanger 24a with a larger number of permanently fixed main bars is evenly fixed on the outer ring structure 1a of the steel bar segment, and the second movable hanger 24b with a smaller number of one-time fixed main bars is evenly fixed on the inner ring structure of the steel bar segment. 1b. The relative height of each movable hanger 24 needs to be adjusted adaptively, which is mainly determined by the length of the rope loop 245 and the length of the adjustable connector. Therefore, in most cases, all hanging points are not coplanar. However, those skilled in the art should understand that when using the adjustable disc-shaped spreader 2 of the present application to lift steel bar segments with circular cross-sections (or other centrally symmetrical cross-sections), the lifting points should be set according to the lifting requirements. At this time, The individual lifting points can be coplanar.

S3, use the hoisting device to hoist the steel bar segments as a whole to the docking position;

Before hoisting the steel bar segment as a whole, perform aerial lifting posture leveling. That is, lift the steel bar segment about 10cm away from the binding platform and observe the inclination of the steel bar segment. At this time, use adjustable connectors for leveling. Specifically, you can use a flower basket screw to match A hand chain hoist levels the rebar segments. After the initial leveling is completed, continue to lift the steel bar segments, and use gradual lifting and translation to lift the steel bar segments above the docking position to prepare for the alignment connection. In fact, the steel bar segment is not guaranteed to be completely deformed when it is in the air, but its controllable deformation can be used to complete the docking later.

S4, after docking the first main reinforcement 11 at the arc section, unload the spreader for the first time; after docking the second main reinforcement 12 at the straight section, evacuate the spreader.

When docking, the bottom opening of the current steel bar segment should be docked and connected with the top opening of the bottom steel bar segment, that is, the main bar connection of the upper and lower steel bar segments should be completed. When installing large-diameter circular cross-section steel bar segments, the steel bar segments are hoisted in place and first connected to the first main bar 11 of the circular arc segment whose deformation is controlled to be small during hoisting. Then the lifting equipment unloads most of the hoisting weight. The unloaded load can be 60% to 85% of the total load, that is, part of the weight of the actual steel segment is transferred from the lifting equipment to the constructed segment. After the support state of the steel segment changes, its overall shape returns to a state closer to the actual connection, that is, The second main bar 12 at the straight line segment whose deformation is controlled to be large during hoisting is reduced from inward or outward deformation and returned to the assembled state, thereby facilitating the connection of the upper and lower steel bar segments. After docking the second main reinforcement at the straight section, evacuate the spreader. After the spreader is evacuated, the binding of the remaining steel bars of the steel bar segment is completed, thereby completing the overall hoisting process of the steel bar segment.

In summary, the overall hoisting method of large-diameter rounded-section steel bar segments in this application utilizes an adjustable disc-shaped spreader, and rationally utilizes the shape and deformation characteristics of large-diameter rounded-section steel bar segments. The deformation is connected first. After connecting the main bars in the smaller arc section, unloading most of the stress on the main hook, let the steel bar sections recover their shape, and then connect the main bars in the straight line section where the deformation is large. In this way, there is no need to take other steps to reduce the steel bar sections. Deformation measures for the overall hoisting of the section, such as adding reinforcing rings or increasing the stiffness of the rigid frame, are measures to increase the overall hoisting weight, save materials and speed up the connection of steel bars.

The above embodiments are preferred implementation modes of the present application, but they are not limited only by the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present application shall be made. Equivalent replacement methods are all included in the protection scope of this application.

Claims (8)

1. A method for integrally hoisting large-diameter rounded-section steel bar segments, which is characterized in that it includes the following steps:

   Bind the steel bar segments according to the preset rounded cross-section profile;

   Set lifting points and connect corresponding lifting devices according to the deformation of the steel bar segments after lifting;

   Use the hoisting device to hoist the steel bar segments as a whole to the docking position;

   After docking the first main bar at the arc section, unload the spreader for the first time;

   After docking the second main reinforcement at the straight section, evacuate the spreader.
2. The method of claim 1, wherein tying steel bar segments according to a preset rounded cross-sectional profile includes:

   Pre-positioning tooth plates according to the docking requirements of the top and bottom openings of the steel bar segments;

   Use the positioning tooth plate to tie the steel bar segments;

   Wherein, the steel bar segments include a stiff frame, most of the main bars and stirrups connecting the main bars.
3. The method according to claim 2, characterized in that after the spreader is evacuated, the binding of remaining steel bars is completed.
4. The method according to claim 1, characterized in that the hanging points are arranged non-coplanar to adapt to the deformation of the steel bar segments.
5. The method according to claim 4, characterized in that the hanging points are arranged on main bars.
6. The method of claim 4, wherein the spreader includes a coplanar upper structure and a non-coplanar lower structure, and the lower structure includes a number of movable hangers suspended below the upper structure, The movable hanger corresponds to the hanging point one-to-one.
7. The method according to claim 6, wherein the movable hanger is connected to the upper structure through an adjustable connector for adjusting the height and plane position of the movable hanger.
8. The method of claim 1, wherein unloading the spreader for the first time includes: unloading 60% to 85% of the total load.

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