CN114541248A - Variable-slope large-section prefabricated superposed beam lifting lug structure and construction method thereof - Google Patents

Abstract

The invention provides a lifting lug structure of a prefabricated superimposed beam with variable slope and large cross-section, which includes a lifting lug main plate, the upper part of the lifting lug main plate is provided with lifting holes, and the lower part of the lifting lug main plate is provided with a lifting lug stiffening plate. The bottom end of the lifting lug main board is provided with a lifting lug bottom plate, and the lifting lug bottom plate is provided with several mounting holes. The invention also provides a construction method of the variable-slope large-section prefabricated composite beam lifting lug structure. The invention solves the problems that the superimposed beam is difficult to install in a complex environment, and the structural stress of the superimposed beam is uneven under special hoisting conditions, and greatly improves the construction safety and saves the construction cost.

Description

A variable-slope large-section prefabricated composite beam lifting lug structure and its construction method

technical field

The invention relates to the technical field of hoisting construction of superimposed beams, in particular to a lifting lug structure of a variable-slope large-section prefabricated superimposed beam and a construction method thereof.

Background technique

With the acceleration of social development, prefabricated components have become the mainstream of modern construction, and the frequency of use of prefabricated components in urban viaducts and highways is becoming more and more common.

Considering the construction work efficiency and cost investment and the convenience of construction, urban viaducts and expressways, in order to improve the work efficiency of prefabricated composite beams in the prefabricated component factory, lifting and installation at the construction site, so the prefabrication process of composite beams and other components Corresponding hoisting points are set according to the predetermined positions. After the maintenance period of the prefabricated components meets the requirements, the prefabricated components are transported to the installation site for hoisting and installation directly.

The conventional methods of pre-embedding hooks include the method of installing steel strand hooks and the method of installing carbon structural steel hooks. Multiple steel strands are used side by side in combination. When the superimposed beam is inclined at any angle, the steel strand hook will be converted from multiple simultaneous forces to single force, which is easy to cause the danger of steel strands breaking one by one; The installation of carbon structural steel hooks is similar to that of steel strand hooks, and is limited to horizontal and stable hoisting of superimposed beams; steel strand hooks and carbon structural steel hooks have high requirements on the anchoring length, and the anchoring ends must be calculated according to the requirements. The corresponding anchor plate is set up and used only once. The one-time use of a large amount of materials is not in line with the concept of energy saving and environmental protection; the conventional method of bottom-housing without pre-embedded hooks causes great difficulty in demoulding and shifting of the superimposed beams in the prefabricated component factory. During the hoisting and installation process, the edges and corners of the superimposed beams are seriously worn on the steel wire ropes, and the consumption of the wire ropes is second only to the pre-embedded hooks, and the appearance of the superimposed beams is easily damaged during the lifting process.

SUMMARY OF THE INVENTION

In order to overcome the deficiencies of the above technologies, the present invention provides a variable-slope and large-section prefabricated composite beam lifting lug structure and a construction method thereof, so as to solve the difficulty in installation and fixation of conventional pre-embedded lifting points on the existing prefabricated composite beams, and the one-time The technical problem is that the material loss is serious and the horizontal lifting of the superimposed beam cannot be realized.

The technical solution adopted by the present invention to overcome its technical problems is as follows: a variable-slope large-section prefabricated composite beam lifting lug structure includes a lifting lug main plate, the upper part of the lifting lug main plate is provided with a lifting hole, and the lifting lug The lower part of the main board is provided with a lifting lug stiffening plate, the bottom end of the main plate of the lifting lug is provided with a lifting lug bottom plate, and a plurality of installation holes are arranged on the lifting lug bottom plate.

Preferably, the lifting lug structure is made of steel material not lower than Q355.

Preferably, the minimum thickness of the lifting lug main plate is 32 mm, the minimum thickness of the lifting lug stiffening plate is 30 mm, and the minimum thickness of the lifting lug bottom plate is 44 mm.

The present invention also provides a construction method of the described variable-slope large-section prefabricated composite beam lifting lug structure, comprising the following steps:

S1, in the prefabrication process of the superimposed beam, a number of fixing holes corresponding to the installation holes are opened on the superimposed beam, a reinforced concrete wet joint is poured on the upper end of the superimposed beam, and a number of reinforced concrete wet joints are opened on the reinforced concrete wet joint. For the reserved holes corresponding to the installation holes, the prefabricated superimposed beams are transported to the site, and the lifting lug structure is lifted. Vertical, the suspension rod is used to pass through the installation hole, the reserved hole and the fixing hole in turn, and fastened by the nut;

S2, using the method of step 1 to install several of the lifting lug structures on the superimposed beam, and by using the combination of different sizes of the lifting lug structures, the vertical and top elevations of the lifting lug structures are consistent;

S3. After all the 8 lifting lugs of a superimposed beam are installed, lift the superimposed beam slowly, leave the installation site by the beam transport ship, and hoist it to the installed/completed cover beam or bracket, and finally install it. to the predetermined location;

S4. After the installation is in place, check whether the center line of the superimposed beam is consistent with the design line of the bridge. After confirming that it is correct, remove the lifting lug structure and hoist the next superimposed beam.

Preferably, in S1, before the lifting lug structure is installed, a wall-protecting steel pipe is pre-buried in the reserved hole for pouring concrete.

Preferably, in S1, the upper part of the boom is fastened by a flat nut, the lower part is fastened by a conical nut, and a steel backing plate is installed between the conical nut and the reinforced concrete wet joint.

Preferably, in S1, the yield strength of the boom is ≥235 MPa, the tensile strength is ≥365 MPa, and the elongation is ≥25%.

Preferably, the thickness of the steel backing plate is 35-44mm.

Compared with the prior art, the beneficial effects of the present invention are: the present invention adopts lifting lugs to lift when the prefabricated composite beam is installed, and solves the conventional methods of pre-embedded hooks, including the method of installing steel strand hooks and the installation of carbon structures. The steel hook method has technical and economic problems such as uneven force on the lifting point, the danger of breaking the steel strands one by one, the inability to achieve inclined hoisting conditions, the easy displacement of the hook during the pre-embedding process, and the increased cost of one-time use. The lifting lug and the superimposed beam installation method of the present invention have the advantages of high strength of the lifting lug, low processing cost, long-term cyclic use after one-time investment, easy replacement of worn parts (high-strength screws and nuts), horizontal hoisting of the superimposed beam, stable hoisting, etc. advantage. It has a very important reference value for the hoisting safety, stability and technical performance of similar prefabricated composite beams, reduces the construction cost investment, and has significant social and economic benefits.

Description of drawings

FIG. 1 is a schematic structural diagram of a variable-slope large-section prefabricated composite beam lifting lug structure of the present invention.

2 and 3 are schematic diagrams of partial structures of FIG. 1 .

FIG. 4 is a schematic view of the construction of a prefabricated composite beam structure with variable slope and large section according to the present invention.

FIG. 5 is a schematic diagram of a partial structure of FIG. 4 .

In the figure, 1. Main board of the lifting lug; 2. Lifting holes; 3. The stiffening plate of the lifting lug; 4. The bottom plate of the lifting lug; 9. Cone nut; 10. Reinforced concrete wet joint; 11. Composite beam; 12. Spreader; 13. Hoisting distribution beam; 14. Lifting equipment.

Detailed ways

In order to make it easy to understand the technical means, creation features, achieved goals and effects of the present invention, the present invention will be further described below with reference to the specific figures.

Example

A prefabricated superimposed beam lifting lug structure with variable slope and large cross-section, as shown in Figure 1-3, includes a lifting lug main plate 1, the upper part of the lifting lug main plate 1 is provided with a lifting hole 2, and the diameter of the lifting hole 2 is 160mm, it can be hoisted by connecting the shaft pin + spreader to the lifting equipment. The lifting hole 2 is connected to the spreader with a shackle of ≥50T level. The 3 fillet welds of the lug stiffening plate are welded, fixed and strengthened. They are located on the left and right sides of the lifting lug main plate 1, and two on each side. Fixing, the lifting lug bottom plate 4 is horizontally arranged along the left and right direction of the lifting lug main plate 1, the lifting lug stiffening plate 3 and the lifting lug main plate 1 and the lifting lug bottom plate 4 are semi-penetrated and welded to be fixed and strengthened, and the lifting lug bottom plate 4 is provided with 8 evenly distributed Mounting holes, the length of the mounting holes is 450mm×32mm.

Further, the lifting lug structure is made of steel material not lower than Q355. According to the weight of the highway and urban elevated superimposed beams, the lifting capacity of a single lifting lug structure is 50t, which can meet the current box girder lifting performance requirements. The minimum thickness of the lifting lug main plate 1 is 32 mm, the minimum thickness of the lifting lug stiffening plate 3 is 30 mm, and the minimum thickness of the lifting lug bottom plate 4 is 44 mm.

A construction method of the variable-slope large-section prefabricated composite beam lifting lug structure, as shown in Figures 1-5, includes the following steps:

S1. During the prefabrication process of the superimposed beam 11, a fixing hole corresponding to the installation hole is opened on the superimposed beam 11, a reinforced concrete wet joint 10 is poured on the upper end of the superimposed beam 11, and a reinforced concrete wet joint 10 is opened. The through reserved holes corresponding to the installation holes are embedded with φ32*3mm protective wall steel pipes 7 in the reserved holes to serve as the guide and protection for the installation of the boom 5 in the later stage. Lifting the lifting lug structure, the lifting lug bottom plate 4 is closely attached to the top surface of the reinforced concrete wet joint 10, so that the lifting lug main plate 1 is kept vertical, and the height of the lifting lug main plate 1 is adjusted so that the top surface elevation of the lifting lug structure is consistent, The hanger rod 5 is used to pass through the installation hole, the reserved hole and the fixing hole in turn, and is fastened and connected by nuts. The upper part of the hanger rod 5 is fastened by the high-strength flat nut 6, and the lower part is fastened by the high-strength cone nut 9. The cone nut 9 is connected to the steel bar. A steel backing plate 8 is installed between the concrete wet joints 10;

S2. The method of step 1 is used to install the lifting lug structure on the superimposed beam 11. Each lateral hoisting section of the superimposed beam 11 is composed of 4 lifting lug structures, and each superposed beam contains 2 hoisting sections in total. There are 8 lifting lug structures, and the vertical and top elevations of the lifting lug structure are consistent by using the combination of different sizes of lifting lug structures to ensure that the superimposed beam 11 can lift the beam under horizontal conditions;

S3. After the 8 lifting lugs of a composite beam are all installed, check the torsion value of the hanging rod 5, check the appearance quality and qualification certificate of the prefabricated concrete components, and check again whether the mileage direction of the composite beam is wrong before lifting. , Review the plane position and elevation of the cover beam/support 15; after checking, connect and fix the hoisting distribution beam 13 and the lifting hole 2 installed on the superimposed beam 11 through the hanger 12. After checking that there is no problem, slowly lift it by about 30cm Carry out a trial hoisting, and leave the installation site by the beam transporting ship. Hoisting to the predetermined drop beam position;

S4. After the installation is in place, check whether the center line of the superimposed beam is consistent with the design line of the bridge. After confirmation, remove the hanger rod 5, flat nut 6 and cone nut 9, release the connection between the superimposed beam 11 and the lifting lug structure, and proceed to the next piece Laminated beam hoisting.

Further, the boom 5 is made of PSB830, grade 25 or higher finishing rebar, its yield strength is ≥235MPa, the tensile strength is ≥365MPa, and the elongation is ≥25%. 35-44mm.

In the present invention, the lifting lug structure is effectively fixed to the superimposed beam 11 by means of high-strength finishing threaded steel and high-strength nuts. , Adjust the height of the main board 1 of the lifting lug, the slope and thickness of the bottom 4 of the lifting lug to make lifting ears of different sizes, and the combined use of the lifting ears of different sizes makes the vertical and top elevations of the lifting ears consistent, which can ensure that the beam is lifted and lifted under the horizontal condition of the superimposed beam. After the height exceeds the cover beam/support 15, adjust the posture of the superimposed beam 11 and install it to the designated drop beam position, the posture of the superimposed beam 11 is more flexible when hoisting, and the connection between the lifting lug structure and the superimposed beam 11 will not cause any disadvantage to the superimposed beam itself influences.

Finally, it should be noted that the above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, for those skilled in the art, the The technical solutions described in the foregoing embodiments may be modified, or some technical features thereof may be equivalently replaced. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims (8)

1. The utility model provides a prefabricated superposed beam lug structure of variable slope large-section, its characterized in that, includes the lug mainboard, the upper portion of lug mainboard is equipped with the jack-up lifting eye, the lower part of lug mainboard is equipped with lug stiffener, the bottom of lug mainboard is equipped with the lug bottom plate, be equipped with a plurality of mounting holes on the lug bottom plate.

2. The variable-slope large-section precast composite beam lifting lug structure according to claim 1, wherein the lifting lug structure is made of steel materials not lower than Q355 grade.

3. The variable-slope large-section precast composite beam lifting lug structure according to claim 1, wherein the minimum thickness of the lifting lug main plate is 32mm, the minimum thickness of the lifting lug stiffening plate is 30mm, and the minimum thickness of the lifting lug bottom plate is 44 mm.

4. A construction method for constructing a lifting lug structure of a variable-slope large-section precast composite beam as claimed in any one of claims 1 to 3, which is characterized by comprising the following steps:

s1, in the process of prefabricating the composite beam, arranging a plurality of fixing holes corresponding to the mounting holes on the composite beam, pouring a reinforced concrete wet joint at the upper end of the composite beam, arranging a plurality of preformed holes corresponding to the mounting holes on the reinforced concrete wet joint, transporting the composite beam to the site after prefabrication is completed, lifting the lifting lug structure, enabling the lifting lug bottom plate to be closely attached to the top surface of the reinforced concrete wet joint, enabling the lifting lug main plate to be vertical, sequentially penetrating the mounting holes, the preformed holes and the fixing holes by using a lifting rod, and fastening by using nuts;

s2, mounting a plurality of lifting lug structures on the superposed beam by adopting the method in the step 1, and realizing the vertical consistency of the lifting lug structures and the top elevation consistency by using the lifting lug structure combinations with different sizes;

s3, after the 8 lifting lug structures of one laminated beam are completely installed, slowly lifting the laminated beam, driving the laminated beam away from an installation site through a beam transporting ship, hoisting the laminated beam to an installed/constructed cover beam or a bracket, and finally installing the laminated beam to a preset position;

and S4, after the composite beam is installed in place, whether the central line of the composite beam is consistent with the designed line type of the bridge or not is checked, and the lifting lug structure is removed after the error is determined to hoist the next composite beam.

5. The construction method according to claim 4, wherein in S1, before the installation of the lifting lug structure, a wall-protecting steel pipe is embedded in the prepared hole of the cast concrete in advance.

6. The construction method according to claim 4, wherein in S1, the upper part of the hanger rod is fastened by a flat nut, the lower part is fastened by a cone nut, and a steel shim plate is installed between the cone nut and the wet joint of the reinforced concrete.

7. The construction method according to claim 4, wherein in S1, the yield strength of the hanger rod is not less than 235MPa, the tensile strength is not less than 365MPa, and the elongation is not less than 25%.

8. The construction method according to claim 6, wherein the thickness of the steel backing plate is 35-44 mm.

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