A bending-shear member based on combined prestressed square piles and its process

Abstract

The present invention provides a bending-shear member and process based on combined prestressed square piles, belonging to the field of building construction technology. Its technical solution is: a bending-shear member based on combined prestressed square piles, characterized in that it includes a plurality of hollow square piles arranged in a matrix, the square pile holes of the hollow square piles are filled with high-strength mortar; it also includes a plurality of shear steel bars uniformly distributed in the square pile holes and passing through the high-strength mortar; the working surfaces of adjacent hollow square piles are bonded by epoxy resin. The beneficial effects of the present invention are: it effectively solves the problem of combined connection of multiple prestressed square piles and local stress reinforcement of the structure when prestressed concrete square piles are used as bending-shear members, fully utilizes the good compressive and tensile properties of prestressed concrete square piles, has a convenient structure, improves construction quality and efficiency, and transforms the bulky prestressed reinforced concrete structure into a light prefabricated structure, which has extremely high social significance for the standardization, intensification and factory production of components.

Description

Technical Field

[0001] The present invention relates to the technical field of building construction, and in particular to a bending-shear member based on combined prestressed square piles and a process thereof. Background Art

[0002] With the continuous development of the precast concrete pile industry, the product specifications of precast concrete piles in my country are becoming increasingly diverse and the combinations are becoming more reasonable. Prestressed concrete square piles are one of the more common types. Currently, the commonly used square pile types in China are mainly divided into two categories: pre-tensioned prestressed centrifugal concrete hollow square piles and pre-tensioned prestressed concrete solid square piles. Each pile type has different advantages and disadvantages.

[0003] Prestressed centrifugal concrete hollow square piles are manufactured using a prestressing process and a concrete centrifugal forming method. They feature a square exterior and a round interior. They combine the excellent shear resistance and high soil lateral friction of solid concrete square piles with the advantages of concrete pipe piles, such as high concrete strength and low material cost. However, as bending-shear components, prestressed concrete square piles are currently only used in foundation construction and serve a limited purpose. To further promote the application of prestressed concrete square piles, we now provide a bending-shear component and process based on modular prestressed square piles. Summary of the Invention

[0004] The purpose of the present invention is to provide a bending-shear member based on combined prestressed square piles and a process.

[0005] The present invention is achieved through the following measures: a bending-shear member based on combined prestressed square piles, characterized in that it includes a plurality of hollow square piles arranged in a matrix, the square pile holes of the hollow square piles are filled with high-strength mortar; the hollow square piles generally adopt 400mm×400mm C60 prestressed concrete hollow square piles.

[0006] The piles are also constructed with several shear reinforcements evenly distributed around the circumference of the pile holes and running through the high-strength mortar to enhance the vertical shear resistance of the pile group. Typically, there are four shear reinforcements evenly distributed around the circumference, with the specific number determined based on actual conditions.

[0007] Adjacent hollow square piles are bonded together with epoxy resin to form a pile group, which is used as a bending-shear member. Typically, a pile group consists of n x m hollow square piles, preferably with n and m being equal, such as 3 x 3 or 4 x 4.

[0008] The number of the longitudinal hollow square piles is greater than three layers, and horizontal cables are arranged through the square pile holes of all the hollow square piles located in the outermost layers at both longitudinal ends. The horizontal cables are concentrically arranged in the square pile holes.

[0009] Several failure sections are provided on the horizontal cables. Some prestressed horizontal cables are wrapped with interlayers or sleeves to separate them from the mortar, preventing further arching and allowing the component to better withstand its own weight and load. The length of the failure section can be determined based on bending moment calculations based on the actual on-site component forces and structural support constraints, and the length of the prestressed failure section can be determined based on the component's tension and compression conditions.

[0010] The horizontal cable is composed of 5 high-strength steel strands with a diameter of 15.24 mm.

[0011] The epoxy resin is 50MPa epoxy resin, and the high-strength mortar is C60 high-strength mortar.

[0012] The shear reinforcement is HRB400 reinforcement with a diameter of 32 mm.

[0013] The location of the failure section in each square pile is different.

[0014] Two vertically adjacent hollow square piles are connected by a connector, which includes a pin steel pipe cast inside one end of the hollow square pile, with the outer end of the pin steel pipe extending out of the hollow square pile; and a steel pipe slot is reserved at the other end for matching with the pin steel pipe;

[0015] A plurality of plug rods are symmetrically arranged on one end of the hollow square pile close to the bolt steel pipe, and a plug rod slot that cooperates with the plug rod is provided at the other end of the hollow square pile;

[0016] The pin steel pipes and the steel pipe slots of two adjacent hollow square piles cooperate with each other and a connecting steel plate is provided between the two hollow square piles, and the connecting steel plate is sleeved on the pin steel pipes.

[0017] A process for forming a bending-shear member based on a combined prestressed square pile, characterized in that shear reinforcement bars are first installed through the pile, and then the horizontal cables are installed by a pre-tensioning method. When the horizontal cables are tensioned, the square pile holes are simultaneously subjected to internal grouting treatment.

[0018] When the grouting strength is greater than 80% of the design strength, the horizontal cables are tensioned.

[0019] Before setting the shear reinforcement, it is necessary to ensure that the bonding strength of the epoxy resin reaches 100% of the square pile strength or to use epoxy resin for bonding installation after the grouting strength is greater than 80% of the design strength.

[0020] The beneficial effects of the present invention are: effectively solving the problem of combined connection of multiple prestressed concrete square piles and local stress reinforcement of the structure when prestressed concrete square piles are used as bending and shear components, making full use of the good compression and tension properties of prestressed concrete square piles, convenient structure, improving construction quality and construction efficiency, and transforming the bulky prestressed reinforced concrete structure into a light assembled structure, which has extremely high social significance for the standardization, intensification and factory production of components. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is the cross-sectional structural diagram of the combined prestressed square pile structure;

[0022] Figure 2 This is a schematic diagram of the longitudinal section of the combined prestressed square pile structure;

[0023] Figure 3 is a structural diagram of the connecting piece;

[0024] Among them, the accompanying drawings are marked as: 1. horizontal cable; 2. hollow square pile; 3. epoxy resin; 4. shear steel bar; 5. mortar; 6. failure section; 7. pin steel pipe; 8. plug rod; 9. steel pipe slot; 10. plug rod slot; 11. connecting steel plate. DETAILED DESCRIPTION

[0025] In order to clearly illustrate the technical features of this solution, this solution is described below through specific implementation methods.

[0026] Example 1:

[0027] See also Figure 1-Figure 2 A flexural-shear member based on combined prestressed square piles includes a plurality of hollow square piles 2 arranged in a matrix, the square pile holes of the hollow square piles 2 are filled with high-strength mortar 5; the hollow square piles 2 generally adopt 400mm×400mm C60 prestressed concrete hollow square piles 2.

[0028] It also includes a number of shear steel bars 4 that are evenly distributed in the square pile holes and penetrate the high-strength mortar 5 to improve the vertical shear resistance of the overall structure of the square pile group.

[0029] The working surfaces of adjacent hollow square piles 2 are bonded together with epoxy resin 3. A certain number of square piles are combined into a square pile group for use as bending-shear members. Generally, a square pile group consists of n x m hollow square piles 2, and preferably n and m are the same, such as 3 x 3, 4 x 4, etc.

[0030] The number of the longitudinal hollow square piles 2 is greater than three layers and the square pile holes of all the hollow square piles 2 located in the outermost layers at both ends of the longitudinal direction are penetrated by horizontal cables 1, which are concentrically arranged in the square pile holes.

[0031] Several failure sections 6 are provided on the horizontal cables 1. Some prestressed horizontal cables 1 are wrapped with interlayers or sleeves to separate them from the mortar 5, preventing further arching and allowing the component to better withstand its own weight and load. The length of the failure section 6 can be determined based on bending moment calculations based on the actual on-site component forces and structural support constraints. The length of the prestressed failure section 6 is then determined based on the component's tension and compression conditions.

[0032] The horizontal cable 1 is composed of 5 high-strength steel strands with a diameter of 15.24 mm.

[0033] Epoxy resin 3 is 50 MPa epoxy resin 3, and high-strength mortar 5 is C60 high-strength mortar 5.

[0034] The shear reinforcement 4 is HRB400 steel bar with a diameter of 32 mm.

[0035] The position of the failure section 6 in each square pile is different.

[0036] Example 2:

[0037] See also Figure 1-Figure 2 Based on the first embodiment, a process for forming a bending-shear member based on a combined prestressed square pile is characterized in that shear reinforcement bars 4 are firstly provided through the pile, and then horizontal cables 1 are provided by a pre-tensioning method. When the horizontal cables 1 are tensioned, internal grouting treatment is simultaneously performed on the pile holes.

[0038] When the grouting strength is greater than 80% of the design strength, the horizontal cable 1 is tensioned.

[0039] Before setting the shear reinforcement 4, it is necessary to ensure that the bonding strength of the epoxy resin 3 reaches 100% of the square pile strength or to perform bonding installation with the epoxy resin 3 after the grouting strength is greater than 80% of the design strength.

[0040] Example 3:

[0041] See also Figure 3 On the basis of the first or second embodiment, two vertically adjacent hollow square piles 2 are connected by a connecting piece, which includes a latch steel pipe 7 cast at one end of the hollow square pile 2, with the outer end of the latch steel pipe 7 extending out of the hollow square pile 2; and a steel pipe slot 9 is reserved at the other end for matching with the latch steel pipe 7;

[0042] A plurality of plug rods 8 are symmetrically arranged on one end of the hollow square pile 2 and close to the bolt steel pipe 7, and a plug rod slot 10 is provided at the other end of the hollow square pile 2 to cooperate with the plug rod 8;

[0043] The pin steel pipes 7 and the steel pipe slots 9 of two adjacent hollow square piles 2 cooperate with each other and a connecting steel plate 11 is provided between the two hollow square piles 2 , and the connecting steel plate 11 is sleeved on the pin steel pipe 7 .

[0044] Among them, the pin steel pipe 7 can reserve holes that cooperate with the horizontal cable 1 and the shear reinforcement 4 according to actual conditions.

[0045] Technical features not described in the present invention can be achieved through or by adopting existing technologies and will not be described in detail here. Of course, the above description is not a limitation of the present invention, and the present invention is not limited to the above examples. Changes, modifications, additions or substitutions made by ordinary technicians in this technical field within the essential scope of the present invention should also fall within the scope of protection of the present invention.

Claims

1. A bending-shear member based on combined prestressed square piles, characterized in that: It comprises a plurality of hollow square piles arranged in a matrix, wherein the square pile holes of the hollow square piles are filled with high-strength mortar; It also includes a number of shear reinforcement bars uniformly distributed circumferentially within the square pile hole and penetrating the high-strength mortar; The working surfaces of adjacent hollow square piles are bonded by epoxy resin; The number of longitudinal hollow square piles is greater than three layers, and horizontal cables are installed through the square pile holes of all the hollow square piles located in the outermost layers at both ends of the longitudinal direction. The horizontal cables are concentrically installed in the square pile holes. The horizontal cable is provided with a plurality of failure sections, and the positions of the failure sections in each square pile are different.

2. The bending-shear member based on combined prestressed square piles according to claim 1 is characterized in that: The horizontal cable is composed of 5 high-strength steel strands with a diameter of 15.24 mm.

3. The bending-shear member based on combined prestressed square piles according to claim 1, characterized in that: The epoxy resin is 50MPa epoxy resin, and the high-strength mortar is C60 high-strength mortar.

4. The bending-shear member based on combined prestressed square piles according to claim 1, characterized in that: The shear reinforcement is HRB400 reinforcement with a diameter of 32 mm.

5. The bending-shear member based on combined prestressed square piles according to claim 1, characterized in that: Two vertically adjacent hollow square piles are connected by a connector, which includes a pin steel pipe cast inside one end of the hollow square pile, with the outer end of the pin steel pipe extending out of the hollow square pile; and a steel pipe slot is reserved at the other end for matching with the pin steel pipe; A plurality of plug rods are symmetrically arranged on one end of the hollow square pile close to the bolt steel pipe, and a plug rod slot that cooperates with the plug rod is provided at the other end of the hollow square pile; The pin steel pipes and the steel pipe slots of two adjacent hollow square piles cooperate with each other and a connecting steel plate is provided between the two hollow square piles, and the connecting steel plate is sleeved on the pin steel pipes.

6. A process for producing a bending-shear member based on a combined prestressed square pile according to claim 1, characterized in that: First, shear reinforcement is installed through the holes, and then the horizontal cables are installed by pre-tensioning. When the horizontal cables are tensioned, the pile holes are simultaneously subjected to internal grouting. When the grouting strength is greater than 80% of the design strength, the horizontal cables are tensioned.

7. A process for producing a bending-shear member based on a combined prestressed square pile according to claim 1, characterized in that: Before setting the shear reinforcement, it is necessary to ensure that the bonding strength of the epoxy resin reaches 100% of the square pile strength or to use epoxy resin for bonding installation after the grouting strength is greater than 80% of the design strength.

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