A connection form between a prefabricated column and a cap and a construction method thereof

Abstract

The present invention provides a connection form between a prefabricated column and a cap and a construction method thereof, characterized in that the cap is divided into two parts, a prefabricated part and a cast-in-place part, the prefabricated part is used as a casting template for the cast-in-place part, and includes a prefabricated cap side wall and a bottom plate, a mortar leveling layer is arranged between the prefabricated bottom plate and the bottom cushion layer, the prefabricated column and the prefabricated cap bottom plate are first supported by a bracket, and finally the remaining part of the cap is cast and connected to form a whole. The connection form and the construction method of the present invention make the connection structure between the prefabricated column and the cap simple, the structure is safe and reliable in force, the requirements for the precision of the prefabrication and pre-embedded construction are low, the construction is convenient, the construction template can be saved, and the project cost can be reduced.

Description

Technical field:

[0001] The invention relates to the technical field of bridge structure design, in particular to a prefabricated assembly technology suitable for bridges, specifically a connection form between a prefabricated column and a cap and a construction method thereof. Background technology:

[0002] The concept of urban construction today is to practice green construction and sustainable development, and the prefabrication and assembly technology that matches this has been rapidly promoted and applied. In urban bridge construction, many bridge upper and lower structures have adopted prefabrication and assembly technology. Despite this, there are still many problems with bridge prefabrication and assembly technology, one of which is how to connect the prefabricated bridge columns and the pedestals.

[0003] Since the connection nodes between columns and caps are usually subjected to large forces and are located in the seismic plastic hinge area, how to ensure that the prefabricated columns and caps can be reliably connected is a key factor affecting the safety of the bridge substructure. At present, the commonly used connection methods between prefabricated columns and caps include grouting sleeve connection, bellows connection, prestressed tendon connection and socket connection. Grouting sleeve connection is easy to install, but the cost is high and the construction accuracy is high; bellows connection is low in cost, but the construction accuracy is high and the transportation and installation are inconvenient; prestressed tendon connection has good seismic self-recovery, but the on-site grouting workload is large and the cost is high; socket connection does not require high construction accuracy, but the depth of the socket is usually 70% to 150% of the column cross-sectional size, resulting in an increase in the amount of work for the cap and column, which reduces the economic efficiency to a certain extent. Summary of the invention:

[0004] The purpose of the present invention is to overcome the above-mentioned problems of the prior art and provide a connection form and construction method of prefabricated columns and pedestals, so as to reduce the connection construction accuracy requirements of prefabricated columns and pedestals, ensure safe and reliable node connections, improve construction convenience, and reduce project costs.

[0005] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0006] On the one hand, the present invention provides a connection form between a prefabricated column and a pedestal, wherein the pedestal is divided into two parts, a prefabricated part and a cast-in-place part. The prefabricated part serves as a casting template for the cast-in-place part, and includes a prefabricated pedestal side wall and a bottom plate. A mortar leveling layer is arranged between the prefabricated bottom plate and the bottom cushion layer. The prefabricated column and the prefabricated pedestal bottom plate are first supported by a bracket, and finally the remaining part of the pedestal is cast and connected to form a whole.

[0007] Furthermore, the cap is a single pile cap structure or a group pile cap structure.

[0008] Furthermore, steel bar joints are reserved at the top and middle of the precast pedestal side walls, and the length of the joints is determined according to the connection method between the cast-in-place steel bars and the joint steel bars, and the connection method is welding or lap joint.

[0009] Furthermore, the thickness of the prefabricated side walls and bottom plate of the pedestal is reduced on the basis of satisfying the requirements of serving as the formwork for the cast-in-place part of the pedestal and bearing the reaction force of the column bracket, thereby reducing the weight of the prefabricated components and facilitating lifting construction.

[0010] Furthermore, a mortar leveling layer is provided between the prefabricated bottom plate of the pedestal and the cushion layer to adjust the pedestal to a horizontal position while ensuring that the pedestal is in close contact with the cushion layer.

[0011] Furthermore, the brackets supporting the prefabricated columns are made of steel structures or concrete structures, and the supporting brackets and the steel bars of the cast-in-place part of the pedestal are staggered.

[0012] Furthermore, the prefabricated side walls and bottom plate of the foundation are roughened or provided with shear teeth to strengthen the connection strength between the cast-in-place part and the prefabricated part.

[0013] Furthermore, the prefabricated columns adopt a concrete structure or a steel structure.

[0014] Furthermore, the cross-section of the bottom of the prefabricated column is circular or polygonal.

[0015] Furthermore, the concrete strength grade of the precast part and the cast-in-place part of the pedestal is the same or the strength grade of the precast part is slightly higher than that of the cast-in-place part, and the concrete strength grade of the pedestal is not lower than C30.

[0016] On the other hand, the present invention also provides a construction method for connecting a prefabricated column with a cap, comprising the following steps:

[0017] A. Pile foundation and cushion layer are constructed on site, and the side wall and bottom plate of the platform are prefabricated in the factory;

[0018] B. The factory ties up the cast-in-place steel bars of the foundation and installs the supporting brackets;

[0019] C. Factory prefabricated columns;

[0020] D. Construct a mortar leveling layer on the cushion layer, and hoist and construct the prefabricated cap side walls and bottom plate on site;

[0021] E. On-site hoisting and construction of prefabricated columns and pouring of concrete in the pedestal to connect them to form a whole.

[0022] The connection form between the prefabricated column and the cap and the construction method thereof provided by the present invention are proposed based on the prefabricated assembly technology and the concept of green construction and sustainable development. Compared with the prior art, the advantages and effects thereof are as follows:

[0023] 1. Compared with the conventional prefabricated column and pedestal connection method, the requirements for construction accuracy can be reduced, and there is a large room for on-site adjustment, which can fully ensure the accuracy of the column pedestal elevation and plane position. Since there is no need for too high construction accuracy requirements, the prefabrication and transportation requirements of the column components are also reduced accordingly.

[0024] 2. Compared with the conventional connection method between prefabricated columns and pedestals, the steel bars at the bottom of the column are cast together with the pedestal. Unlike the grouting sleeve connection, corrugated pipe connection and prestressed tendon connection, which require special connectors, its stress performance is consistent with the cast-in-place structure, and the connection is safe and reliable.

[0025] 3. Compared with the grouting sleeve connection and the corrugated pipe connection, the reinforcement of the prefabricated column is not restricted by the connectors. A high reinforcement ratio design can be used on high piers and columns with greater stress, which provides engineers with more options and can also increase the prefabrication rate of engineering projects.

[0026] 4. Compared with the grouting sleeve connection, the bellows connection and the prestressed tendon connection, the connection between the prefabricated column and the cap does not require a connector or grouting filling material; compared with the socket-and-spigot connection, there is no need to set a socket slot, weaken the cap structure, and increase the length of the prefabricated column; the side wall and bottom plate of the prefabricated cap can be used as a casting template, which also reduces the amount of template engineering. Therefore, the present invention can reduce the amount of engineering and reduce the engineering cost. Description of the drawings:

[0027] Figure 1 It is one of the schematic diagrams of the construction method in the embodiment, Figure a is a schematic diagram of the prefabricated side wall and bottom plate of the pedestal and the prefabricated part of the reinforcement of the pedestal, and Figure b is a schematic diagram of the pile foundation, pile foundation reinforcement and bottom cushion layer.

[0028] Figure 2 This is the second schematic diagram of the construction method in the embodiment.

[0029] Figure 3 This is the third schematic diagram of the construction method in the embodiment.

[0030] Figure 4 This is the fourth schematic diagram of the construction method in the embodiment.

[0031] Figure 5 This is the fifth schematic diagram of the construction method of the embodiment.

[0032] In the figure:

[0033] Prefabricated cap side walls and bottom plate 1, prefabricated part steel bars of the cap 2, pile foundation 3, pile foundation steel bars 4, bottom cushion 5, supporting bracket 6, cast-in-place part steel bars of the cap 7, prefabricated concrete columns 8, column steel bars 9, prefabricated steel structure columns 10, column shear keys 11, mortar leveling layer 12, cast-in-place part of the cap 13. Specific implementation method:

[0034] The present invention is described clearly and completely below based on the drawings and specific embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field belong to the scope of protection of the present invention.

[0035] Example

[0036] The present embodiment is a connection form between a prefabricated column and a cap used in the prefabricated assembly of a bridge. The cap is divided into two parts, a prefabricated part and a cast-in-place part. The prefabricated part serves as a casting template for the cast-in-place part, including a prefabricated cap side wall and a bottom plate. A mortar leveling layer is arranged between the prefabricated bottom plate and the bottom cushion layer. The prefabricated column and the prefabricated cap bottom plate are first supported by a bracket, and finally the remaining part of the cap is cast and connected to form a whole.

[0037] During specific implementation, the cap may adopt a single pile cap structure or a group pile cap structure.

[0038] During the specific implementation, steel bar joints should be reserved at the top and middle of the side walls of the precast pedestal. The length of the joints can be determined according to the connection method between the cast-in-place steel bars and the joint steel bars. The connection method can be welding or overlapping according to the size of the pedestal structure and the construction equipment.

[0039] In the specific implementation, the thickness of the prefabricated side wall of the pedestal as the template for the cast-in-place part of the pedestal should ensure that the deformation of the side wall meets the requirements during pouring, and the prefabricated pedestal bottom plate should be partially thickened at the bracket position to withstand the reaction force of the column bracket. On this basis, the thickness of the side wall and bottom plate of the prefabricated pedestal should not be too conservative, and the weight of the prefabricated components should be reduced as much as possible to facilitate hoisting construction.

[0040] During specific implementation, a mortar leveling layer can be set between the prefabricated base plate of the pedestal and the cushion layer to adjust the pedestal to a horizontal position while ensuring that the pedestal is in close contact with the cushion layer.

[0041] During specific implementation, the bracket supporting the prefabricated column can be made of steel structure or concrete structure. When the supporting bracket conflicts with the main stress-bearing reinforcement of the cast-in-place part, the position of the bracket should be adjusted to ensure that the main stress-bearing reinforcement remains unchanged. When it conflicts with non-stress-bearing reinforcement, the reinforcement or bracket can be adjusted.

[0042] During specific implementation, in order to improve the connection strength between the cast-in-place part and the prefabricated part of the pedestal, the prefabricated side walls and the inside of the bottom plate of the pedestal may be roughened or shear teeth may be provided.

[0043] In specific implementation, prefabricated columns can be made of concrete structure or steel structure. The main reinforcement at the bottom of the concrete structure column extends into the pedestal, and the steel plate at the bottom of the steel structure column extends into the pedestal, and shear keys are set on the inside or outside of the steel plate or both the inside and outside.

[0044] During specific implementation, the bottom cross-section of the prefabricated column can be a common circle or rectangle, or a polygon with a large cut angle to enhance the three-dimensional landscape effect of the column.

[0045] During specific implementation, the concrete strength grade of the precast part and the cast-in-place part of the pedestal can be kept the same. When it is necessary to reduce the hoisting weight of the precast part and reduce the slab thickness, the concrete strength grade of the precast part can also be appropriately increased. The concrete strength grade of the pedestal should not be lower than C30.

[0046] A construction method for connecting a prefabricated column with a cap comprises the following steps:

[0047] A. See Figure 1 , construct the pile foundation steel bars 4 on site, pour the pile foundation 3 and the bottom cushion 5, and simultaneously erect the formwork in the prefabrication plant to tie the prefabricated part of the cap steel bars 2, and prefabricate the cap side walls and bottom plate 1;

[0048] B. See Figure 2 The factory ties the cast-in-place steel bars 7 of the foundation and installs the support bracket 6. If there is a conflict between the bracket and the steel bar during the tying process, the corresponding adjustment plan is determined according to whether the conflict is the stress-bearing steel bar or the non-stress-bearing steel bar;

[0049] C. See Figure 3 , prefabricated columns in the factory, if the columns are made of concrete, the column steel bars 9 should be tied in the factory and poured to form prefabricated concrete columns 8, if the columns are made of steel, the steel structure prefabricated columns 10 should be cut and welded in the factory, and the column shear keys 11 should be welded at the bottom of the columns;

[0050] D. See Figure 4 , construct a mortar leveling layer 12 on the bottom cushion layer 5, and use a crawler crane or a truck crane to hoist and construct the prefabricated cap side wall and bottom plate 1 on site;

[0051] E. See Figure 5 , the prefabricated columns are installed on site using crawler cranes, automobile cranes or integrated bridge erection machines. After the positions of the columns are adjusted, the cast-in-place part 13 of the cap is cast and connected to form a whole.

[0052] The connection form and construction method of the prefabricated column and the pedestal of the present invention can reduce the connection construction accuracy requirements of the prefabricated column and the pedestal, ensure the safety and reliability of the node connection, improve the construction convenience, and reduce the project cost.

[0053] Although the specific embodiments of the present invention are described above, it should be understood by those skilled in the art that these are only preferred embodiments of the present invention. For those skilled in the art to which the present invention belongs, it is obvious that various modifications and substitutions can be made on the premise of understanding the concept of the present invention, which should all be regarded as belonging to the protection scope of the present invention.

Claims

1. A connection form between a prefabricated column and a cap, characterized in that: The pedestal includes two parts, prefabricated and cast-in-place; the prefabricated part serves as a casting template for the cast-in-place part, including the side walls and bottom plate of the prefabricated pedestal, and steel bar joints are reserved at the top and middle of the side walls of the prefabricated pedestal. The length of the joint is determined according to the connection method between the steel bars of the cast-in-place part and the steel bars of the joint, and the connection method adopts welding or lap joint; the inside of the side walls and bottom plate of the prefabricated pedestal is roughened or shear teeth are provided; a mortar leveling layer is provided between the bottom plate of the prefabricated pedestal and the bottom cushion layer to adjust the pedestal to a horizontal position and make the pedestal and the cushion layer close to each other; the prefabricated columns and the bottom plate of the prefabricated pedestal are first supported by brackets, and the brackets are staggered with the steel bars of the cast-in-place part of the pedestal, and finally the remaining part of the pedestal is cast and connected to form a whole; the side walls and bottom plate of the prefabricated pedestal are thinned on the basis of meeting the requirements of serving as the template of the cast-in-place part of the pedestal and bearing the reaction force of the column bracket.

2. A connection form between a prefabricated column and a cap as claimed in claim 1, characterized in that: The cap is a single pile cap structure or a group pile cap structure.

3. The connection form between the prefabricated column and the cap according to claim 1 is characterized in that: The bracket supporting the prefabricated columns adopts a steel structure or a concrete structure.

4. The connection form between the prefabricated column and the cap according to claim 1 is characterized in that: The prefabricated columns are made of concrete structure or steel structure.

5. The connection form between the prefabricated column and the cap according to claim 1 is characterized in that: The bottom cross-section of the prefabricated column is circular or polygonal.

6. The connection form between the prefabricated column and the cap according to claim 1, characterized in that: The concrete strength grade of the prefabricated part and the cast-in-place part of the foundation is the same or the strength grade of the prefabricated part is slightly higher than that of the cast-in-place part, and the concrete strength grade is not lower than C30.

7. The connection form between the prefabricated column and the cap according to claim 1, characterized in that: The construction method includes the following steps: A. Pile foundation and cushion layer are constructed on site, and the side wall and bottom plate of the platform are prefabricated in the factory; B. The factory ties up the cast-in-place steel bars of the foundation and installs the supporting brackets; C. Factory prefabricated columns; D. Construct a mortar leveling layer on the cushion layer, and hoist and construct the prefabricated cap side walls and bottom plate on site; E. On-site hoisting and construction of prefabricated columns and pouring of concrete in the pedestal to connect them to form a whole.

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