Steel tenon key and assembling method for improving shear strength of precast beam segment assembling

Abstract

The present invention discloses a steel tenon key and an assembling method for improving the shear strength of precast beam segment assembling, which includes a matching tenon head component and a tenon hole component. The tenon head component and the tenon hole component are respectively installed at the opposite ends of the first segment and the second segment. The tenon head component includes a first embedded segment embedded inside the first segment and a tenon head protruding from the end face of the first segment. The tenon hole component includes a second embedded segment embedded inside the second segment and a tenon hole opened at the end of the second embedded segment. At least the two axial ends of the first embedded segment and the second embedded segment are rectangular prism structures. The steel tenon key and the assembling method for improving the shear strength of precast beam segment assembling disclosed by the present invention transfer the bearing capacity through the plane of the rectangular prism, with a small stress concentration area between the steel tenon key and the concrete and high shear strength.

Description

Technical Field

[0001] The present invention relates to a shear key for assembling precast beam segments, and particularly to a steel tenon key and an assembling method for improving the shear strength of precast beam segment assembly. Background Art

[0002] At present, in the assembly of precast beam segments, two forms are usually adopted to improve the shear strength: First, the opposite segment end faces are connected by inserting a toothed concrete structure. The forms of the toothed concrete structure include rectangle, trapezoid, triangle, etc. The toothed structure joint can play a shear resistance role and improve the strength at the joint. However, the toothed key joint needs to be precast by the close pouring method, and a complex toothed key model needs to be installed, with complex technology. At the same time, the positioning accuracy of the concrete toothed key is low. Second, tenon keys are embedded inside the beam end bearing area. The cross-sections of the existing tenon keys are all circular structures. Under the action of force at the beam end, the force exerted by the tenon key on the concrete generates vertical and horizontal component forces. The horizontal component force generates horizontal tensile stress on the concrete bearing area under the tenon key. Since the axial tensile strength of concrete is about 1 / 10 of the axial compressive strength, it is easy to damage the beam end concrete. And there is a problem of contact stress concentration between the cylindrical tenon key and the concrete. When machining the anchorage groove, the structure and technology are complex, which also reduces the strength of the steel tenon key. Summary of the Invention

[0003] In view of the above problems, the present invention provides a steel tenon key and an assembling method for improving the shear strength of precast beam segment assembly, aiming to solve the problems that the concrete of the existing precast beam segment is easily damaged under the action of horizontal force, the shear strength of the shear key for segment assembly is low, the stress concentration area between the tenon key and the concrete is large, and the preparation process is cumbersome.

[0004] The present invention adopts the following technical solutions to achieve the above object:

[0005] A steel tenon key for improving the shear strength of precast beam segment assembly, the precast beam at least includes a first segment and a second segment; the steel tenon key includes a matching tenon head assembly and tenon hole assembly, and the tenon head assembly and tenon hole assembly are respectively installed at the opposite ends of the first segment and the second segment; the tenon head assembly includes a first embedded segment embedded inside the first segment and a tenon head protruding from the end face of the first segment, and the first embedded segment and the tenon head are coaxial and integrally formed; the tenon hole assembly includes a second embedded segment embedded inside the second segment and a tenon hole opened at the end of the second embedded segment, the tenon hole is coaxial with the second embedded segment and is inserted with the tenon head, wherein, the tenon head and the tenon hole are in clearance fit; at least the two axial ends of the first embedded segment and the second embedded segment are rectangular parallelepiped structures.

[0006] In this technical solution, at least the two axial ends of the first pre-embedded section and the second pre-embedded section are made into a cuboid structure. The bearing capacity of the first section and the second section is transmitted to the concrete through the side surface of the cuboid in the vertical direction. The concrete only bears the vertical pressure, and it is not easy to damage the concrete structure at the beam end. Moreover, the bearing capacity is transmitted through the plane, and the stress concentration area between the steel tenon key and the concrete is small, and the shear strength is high. In the prior art, for the cylindrical tenon key, the bearing capacity of the first section and the second section is transmitted to the concrete through the side surface of the cylinder. The force exerted by the cylinder on the concrete is decomposed into vertical and horizontal component forces. The horizontal component force generates horizontal tensile stress on the concrete bearing area under the tenon key. Since the axial tensile strength of concrete is about 1 / 10 of the axial compressive strength, the cylindrical tenon key is prone to damage the concrete structure at the beam end due to the action of the horizontal component force, and the stress concentration area between the tenon key and the concrete is relatively large, and the shear strength is low.

[0007] A further technical solution thereof is that the whole of the first pre-embedded section and the second pre-embedded section is a cuboid structure.

[0008] A further technical solution thereof is that an anchoring structure is provided between the two axial ends of the first pre-embedded section and the second pre-embedded section respectively. The anchoring structure of this technical solution is used to improve the anchoring force between the steel tenon key and the concrete.

[0009] A further technical solution thereof is that the two axial ends of the first pre-embedded section and the second pre-embedded section are cuboid structures; the anchoring structure is a cylindrical structure with the top surface and the bottom surface respectively connecting the end faces of the two cuboids at both ends, and the outer diameter of the cylindrical structure is smaller than the outer diameters of the two cuboids at both ends. In this technical solution, an anchoring structure is formed by cuboids and cylinders with different outer diameters to improve the anchoring force between the steel tenon key and the concrete.

[0010] A further technical solution thereof is that the anchoring structure is an anchoring rib protruding from the periphery of the first pre-embedded section and the second pre-embedded section. In this technical solution, the anchoring force between the steel tenon key and the concrete is improved by installing anchoring ribs on the periphery of the first pre-embedded section and the second pre-embedded section.

[0011] A further technical solution thereof is that the anchoring rib is one of a semi-circular or polygonal structure.

[0012] A further technical solution thereof is that the joint between the first section and the second section is a flat joint. In this technical solution, by using a flat joint with a steel tenon key to replace the toothed joint in the prior art, the design of the beam end of the segment can be simplified, the close pouring of the segment assembly joint in the past can be cancelled, and the precast process can be simplified.

[0013] A method for assembling precast beam segments, including the above-mentioned steel tenon key, and its assembling method includes the following steps:

[0014] A) Install the formwork, which is for precast segments and has flat joint structures at both ends. Reserve prestressed ducts at preset positions and tie the steel bar mesh.

[0015] B) Embed steel tenon keys. Embed the mating tenon components and mortise components at the opposite ends of the first segment and the second segment respectively, and pour concrete. Among them, the quantity, size and layout positions of the steel tenon keys are determined according to the shear force that the splicing joint of the segment beam needs to bear.

[0016] C) Assemble and position. Control the relative positions of the first segment and the second segment through a hoisting device to make the tenon and the mortise coaxial.

[0017] D) Assemble and connect. Connect the first segment and the second segment through the tenon and the mortise, where the tenon and the mortise are inserted and have a clearance fit.

[0018] E) Tension construction. Thread prestressing tendons through the reserved prestressed ducts, install gaskets and anchors at both ends and tension the prestressing tendons.

[0019] In the connection method of this technical solution, a flat joint with a steel tenon key is used to replace the toothed key joint in the prior art, which can simplify the design of the segment beam end, cancel the close pouring of the prior segment assembly joint, and simplify the precast process.

[0020] The beneficial effects of the present invention are:

[0021] A steel tenon key and an assembly method for improving the shear strength of precast beam segments provided by the present invention make at least the two axial ends of the first embedded section and the second embedded section into a cuboid structure. The bearing capacities of the first segment and the second segment are transmitted to the concrete through the vertical side surfaces of the cuboid. The concrete only bears the vertical pressure and is not easily damaged to the concrete structure at the beam end. Moreover, the bearing capacity is transmitted through the plane, and the stress concentration area between the steel tenon key and the concrete is small, and the shear strength is high. By using a flat joint with a steel tenon key to replace the toothed key joint in the prior art, the design of the segment beam end can be simplified, the close pouring of the prior segment assembly joint can be cancelled, and the precast process can be simplified. Description of the Drawings

[0022] Figure 1 It is: a schematic structural diagram of a precast beam with a cylindrical tenon key in the prior art.

[0023] Figure 2 It is: a schematic structural diagram of a cylindrical tenon key in the prior art.

[0024] Figure 3 It is: a schematic diagram of the force analysis of the beam end concrete with a cylindrical tenon key in the prior art.

[0025] Figure 4It is: Schematic diagram of the precast beam structure with steel tenon keys having cuboid shapes at both ends according to the present invention.

[0026] Figure 5 It is: Schematic diagram of the structure of the steel tenon key with cuboid shapes at both ends according to the present invention.

[0027] Figure 6 It is: Schematic diagram of the insertion structure of the steel tenon key with cuboid shapes at both ends according to the present invention.

[0028] Figure 7 It is: Schematic diagram of the stress analysis of the concrete at the beam end of the precast beam with steel tenon keys having cuboid shapes at both ends according to the present invention.

[0029] Figure 8 It is: Schematic diagram of the precast beam structure with steel tenon keys having an overall cuboid shape according to the present invention.

[0030] Figure 9 It is: Schematic diagram of the structure of the steel tenon key having an overall cuboid shape according to the present invention.

[0031] Figure 10 It is: Schematic diagram of the insertion structure of the steel tenon key having an overall cuboid shape according to the present invention.

[0032] Figure 11 It is: Schematic diagram of the precast beam structure with steel tenon keys having an overall cuboid shape and without an anchoring structure according to the present invention.

[0033] Figure 12 It is: Schematic diagram of the structure of the steel tenon key having an overall cuboid shape and without an anchoring structure according to the present invention.

[0034] In the figure:

[0035] 1. First segment; 2. Second segment; 10. Tenon head assembly; 100. First embedded segment; 11. Tenon head; 12. First end of the first embedded segment; 13. Second end of the first embedded segment; 14. Cylindrical anchoring structure of the first embedded segment; 15. Anchoring rib of the first embedded segment; 20. Mortise hole assembly; 200. Second embedded segment; 21. Mortise hole; 22. First end of the second embedded segment; 23. Second end of the second embedded segment; 24. Cylindrical anchoring structure of the second embedded segment; 25. Anchoring rib of the second embedded segment; 3. Concrete. Detailed implementation manners

[0036] Next, the present invention will be described in detail with reference to the attached Figures 1 to 12 , comparative examples and detailed implementation manners. Without conflict, the following embodiments and the features in the embodiments can be combined with each other.

[0037] Comparative example, such as Figures 1 to 3As shown, a steel tenon key for assembling precast beam segments of the prior art is provided. The precast beam includes a first segment 1 and a second segment 2 assembled through a flat joint. The steel tenon key includes a tenon head assembly 10 and a tenon hole assembly 20, and the tenon head assembly 10 and the tenon hole assembly 20 are respectively installed at the opposite ends of the first segment 1 and the second segment 2. The tenon head assembly 10 includes a first embedded segment 100 embedded inside the first segment 1 and a tenon head 11 protruding from the end face of the first segment 1. The first embedded segment 100 and the tenon head 11 are coaxial and integrally formed. The tenon hole assembly 20 includes a second embedded segment 200 embedded inside the second segment 2 and a tenon hole 21 opened at the end of the second embedded segment 200. The tenon hole 21 is coaxial with the second embedded segment 200 and is inserted into the tenon head 11. Among them, the tenon head 11 and the tenon hole 21 are in clearance fit. Both the first end 12 and the second end 13 of the first embedded segment 100 along the axial direction of the first embedded segment 100 are cylindrical structures. Both the first end 22 and the second end 23 of the second embedded segment 200 along the axial direction of the second embedded segment 200 are cylindrical structures. The first end 12 and the second end 13 of the first embedded segment 100 are connected by a first embedded segment cylindrical anchoring structure 14, and the outer diameter of the first embedded segment cylindrical anchoring structure 14 is smaller than the outer diameters of the first end 12 and the second end 13 of the first embedded segment 100. The first end 22 and the second end 23 of the second embedded segment 200 are connected by a second embedded segment cylindrical anchoring structure 24, and the outer diameter of the second embedded segment cylindrical anchoring structure 24 is smaller than the outer diameters of the first end 22 and the second end 23 of the second embedded segment 200.

[0038] In this comparative example, as Figure 3 shown, when the first segment 1 and the second segment 2 undergo relative shear movement, the steel tenon key transmits the acting force Fq to the concrete 3 through the cylindrical structure. Fq3 is the acting force vertically downward, and Fq1 and Fq2 are the acting forces in the inclined directions. For example, Fq1 can be decomposed into a horizontal acting force F1 and a vertical acting force F2. The horizontal acting force F1 generates a horizontal tensile stress on the concrete 3 bearing area under the tenon key. The axial tensile strength of the concrete 3 is about 1 / 10 of the axial compressive strength. Therefore, for the cylindrical steel tenon key in this comparative example, the horizontal acting force F1 acting on the concrete 3 can cause damage to the concrete structure at the beam end.

[0039] Another embodiment, as Figures 4 to 7As shown in the figure, this embodiment provides a steel tenon key for improving the shear strength of precast beam segment assembly. The precast beam includes a first segment 1 and a second segment 2 assembled through a flat joint. The steel tenon key includes a tenon head assembly 10 and a tenon hole assembly 20. The tenon head assembly 10 and the tenon hole assembly 20 are respectively installed at the opposite ends of the first segment 1 and the second segment 2. The tenon head assembly 10 includes a first embedded segment 100 embedded inside the first segment 1 and a tenon head 11 protruding from the end face of the first segment 1. The first embedded segment 100 and the tenon head 11 are coaxial and integrally formed. The tenon hole assembly 20 includes a second embedded segment 200 embedded inside the second segment 2 and a tenon hole 21 opened at the end of the second embedded segment 200. The tenon hole 21 is coaxial with the second embedded segment 200 and is inserted with the tenon head 11. Among them, the tenon head 11 and the tenon hole 21 are in clearance fit. Both the first end 12 and the second end 13 of the first embedded segment 100 along the axial direction of the first embedded segment 100 are rectangular parallelepiped structures. Both the first end 22 and the second end 23 of the second embedded segment 200 along the axial direction of the second embedded segment 200 are rectangular parallelepiped structures. The first end 12 and the second end 13 of the first embedded segment 100 are connected by a first embedded segment cylindrical anchoring structure 14. The outer diameter of the first embedded segment cylindrical anchoring structure 14 is smaller than the outer diameters of the first end 12 and the second end 13 of the first embedded segment 100, which is used to improve the anchoring force between the first embedded segment 100 and the concrete 3. The first end 22 and the second end 23 of the second embedded segment 200 are connected by a second embedded segment cylindrical anchoring structure 24. The outer diameter of the second embedded segment cylindrical anchoring structure 24 is smaller than the outer diameters of the first end 22 and the second end 23 of the second embedded segment 200, which is used to improve the anchoring force between the second embedded segment 200 and the concrete 3.

[0040] In this embodiment, as Figure 7 shown, when the first segment 1 and the second segment 2 undergo relative shear movement, the steel tenon key transfers the acting force Fq of the first segment 1 and the second segment 2 to the concrete 3 through the rectangular parallelepiped structures on the side surfaces in the vertical direction at both ends of the first embedded segment 100 and the second embedded segment 200. Fq are all acting forces vertically downward. The steel tenon key structure in this embodiment only transfers the acting force vertically downward to the concrete and has no acting force in the horizontal direction. Therefore, it is not easy to damage the concrete structure at the beam end. The planar structure in this embodiment can reduce the stress concentration between the steel tenon key and the concrete compared with the curved surface structure in the prior art, and improve the shear strength. In addition, the splicing structure with a flat joint can simplify the process design of the tooth joint segment beam end in the prior art, and can cancel the close pouring of the segment assembly joint in the past, simplifying the precast process.

[0041] The above embodiment exemplarily shows the specific structure of the first segment 1 and the second segment 2 assembled through a flat joint. According to other embodiments or practical applications, the first segment 1 and the second segment 2 can also be assembled through a structure form of dense teeth or sparse teeth.

[0042] The above embodiments exemplarily show a precast beam assembly structure including a first section 1 and a second section 2. A tenon assembly 10 is embedded at the end face of the first section 1 relative to the second section 2, and a mortise assembly 20 is embedded at the end face of the second section 2 relative to the first section 1. In other embodiments or practical applications, the precast beam further includes a third section assembled with the other end of the first section 1 and a fourth section assembled with the other end of the second section 2. Tenon assemblies 10 and mortise assemblies 20 are respectively embedded at the opposite end faces of the first section 1 and the third section, and tenon assemblies 10 and mortise assemblies 20 are respectively embedded at the opposite end faces of the second section 2 and the fourth section; or tenon assemblies 20 and mortise assemblies 10 are respectively embedded at the opposite end faces of the first section 1 and the third section, and tenon assemblies 20 and mortise assemblies 10 are respectively embedded at the opposite end faces of the second section 2 and the fourth section, etc.; that is, both ends of the first section 1 can be tenon assemblies 10 or one end is a tenon assembly 10 and the other end is a mortise assembly 20, and both ends of the second section 2 can be mortise assemblies 20 or one end is a tenon assembly 10 and the other end is a mortise assembly 20.

[0043] The above embodiments exemplarily show a structure in which both ends of the first embedded section 100 and the second embedded section 200 are rectangular parallelepipeds and are connected by a cylindrical anchoring structure with an outer diameter smaller than that of the two ends of the rectangular parallelepipeds; according to other embodiments or practical applications, it can also be replaced by the first embedded section 100, the second embedded section 200 and the anchoring structure of other shapes, such as Figures 8 to 10 , on the basis of the above embodiments, both the first embedded section 100 and the second embedded section 200 are rectangular parallelepiped structures. Among them, four side faces in the axial direction of the first embedded section 100 are provided with protruding first embedded section anchoring ribs 15, and four side faces in the axial direction of the second embedded section 200 are provided with protruding second embedded section anchoring ribs 25. The first embedded section anchoring ribs 15 and the second embedded section anchoring ribs 25 can be specifically connected by welding, integral molding, etc., and the specific shape can be a semicircle, a polygon, etc. The connection method and the specific shape of the anchoring ribs can be determined according to specific construction conditions and are not limited here; similarly, the steel tenon key in this embodiment transfers the acting force Fq of the first section 1 and the second section 2 to the concrete 3 through the side faces in the vertical direction of the rectangular parallelepiped structure. Fq are all acting forces vertically downward. The steel tenon key structure in this embodiment only transfers the acting force vertically downward to the concrete and has no acting force in the horizontal direction. Therefore, it is not easy to damage the concrete structure at the beam end; the plane structure in this embodiment can reduce the stress concentration at the end of the segment beam compared with the curved surface structure in the prior art.

[0044] The above embodiments exemplarily show that the first embedded section 100 and the second embedded section 200 are respectively provided with anchoring structures (cylindrical anchoring structure and anchoring ribs). The above anchoring structures are only for improving the anchoring force between the embedded section and the concrete, such as Figure 11, Figure 12 As shown, in embodiments where other anchoring forces are sufficient, this anchoring structure is a non-essential technical feature.

[0045] In another embodiment, based on the above embodiment, this embodiment provides a method for assembling precast beam segments, including the following steps:

[0046] A) Install the formwork. Install the formwork for precast segments. The two ends of the formwork are flat joint structures, and prestressed ducts are reserved at preset positions, and the steel bar mesh is tied. The flat joint structure can simplify the process design of the tooth joint segment beam end in the prior art, cancel the close pouring of the segment assembly joint in the past, and simplify the precast process;

[0047] B) Embed steel tenon keys. Determine the quantity, size and layout positions of the steel tenon keys according to the shear force design required by the segment beam splicing joint. Embedded mating tenon components 10 and tenon hole components 20 are respectively embedded at the opposite end parts of the first segment 1 and the second segment 2, and concrete is poured. The first embedded section 100 and the second embedded section 200 are respectively embedded in the concrete of the first segment 1 and the second segment 2, so that the tenon 11 protrudes from the first segment 1, and the tenon hole 21 is exposed at the end of the second segment 2;

[0048] C) Assembly and positioning. Control the relative positions of the first segment 1 and the second segment 2 through a hoisting device to make the tenon 11 and the tenon hole 21 coaxial;

[0049] D) Assembly connection. Connect the first segment 1 and the second segment 2 through the tenon 11 and the tenon hole 21, wherein the tenon 11 and the tenon hole 21 are inserted and have a clearance fit;

[0050] E) Tensioning construction. Pass prestressed tendons through the reserved prestressed ducts, install gaskets and anchors at both ends and tension the prestressed tendons.

[0051] A steel tenon key and an assembly method for improving the shear strength of precast beam segment assembly provided by the present invention make at least the axial two ends of the first embedded section 100 and the second embedded section 200 into cuboid structures. The bearing capacity of the first segment 1 and the second segment 2 is transmitted to the concrete 3 through the side surfaces of the cuboid in the vertical direction. The concrete 3 only bears the vertical pressure, and it is not easy to damage the concrete structure at the beam end. Moreover, the bearing capacity is transmitted through the plane, and the stress concentration area between the steel tenon key and the concrete is small, and the shear strength is high; by using a flat joint with a steel tenon key to replace the tooth key joint in the prior art, the design of the segment beam end can be simplified, the close pouring of the segment assembly joint in the past can be cancelled, and the precast process can be simplified.

Claims

1. A steel tenon key for improving the shear strength of precast beam segment assembly, the precast beam at least comprising a first segment and a second segment; characterized in that, The steel tenon key includes a mating tenon head assembly and tenon hole assembly. The tenon head assembly and tenon hole assembly are respectively installed at the opposite ends of the first segment and the second segment. The tenon head assembly includes a first embedded segment embedded inside the first segment and a tenon head protruding from the end face of the first segment. The first embedded segment and the tenon head are coaxial and integrally formed. The tenon hole assembly includes a second embedded segment embedded inside the second segment and a tenon hole opened at the end of the second embedded segment. The tenon hole is coaxial with the second embedded segment and is inserted into the tenon head. Among them, the tenon head and the tenon hole are in clearance fit, and the ends of the tenon head and the tenon hole are of planar structure. At least the axial two ends of the first embedded segment and the second embedded segment are of cuboid structure. The joint between the first segment and the second segment is a flat joint.

2. The steel tenon key for improving the shear strength of precast beam segment assembly according to claim 1, wherein The whole of the first embedded segment and the second embedded segment is of cuboid structure.

3. A steel tenon key for improving the shear strength of precast beam segment assembly according to any one of claims 1 or 2, characterized in that, The first embedded segment and the second embedded segment are respectively provided with an anchoring structure between the two axial ends.

4. A steel tenon key for improving the shear strength of precast beam segment assembly according to claim 3, characterized in that, The axial two ends of the first embedded segment and the second embedded segment are of cuboid structure. The anchoring structure is a cylindrical structure with the top and bottom respectively connecting the end faces of the two cuboids at both ends. The outer diameter of the cylindrical structure is smaller than the outer diameters of the two cuboids at both ends.

5. A steel tenon key for improving the shear strength of precast beam segment assembly according to claim 3, characterized in that, The anchoring structure is an anchoring rib protruding from the periphery of the first embedded segment and the second embedded segment.

6. The steel tenon key for improving the shear strength of precast beam segment assembly according to claim 5, characterized in that, The anchoring rib is one of a semi-circular or polygonal structure.

7. A method for assembling precast beam segments, characterized in that, Including the steel tenon key according to any one of claims 1 to 6, the assembling method thereof includes the following steps: A) Install the formwork, install the formwork for the precast segment. The two ends of the formwork are of flat joint structure, and prestressing ducts are reserved at preset positions, and the steel bar mesh is tied. B) Embed the steel tenon key, respectively embed the mating tenon head assembly and tenon hole assembly at the opposite ends of the first segment and the second segment, and pour concrete. C) Assemble and position, control the relative positions of the first segment and the second segment through a hoisting device to make the tenon head and the tenon hole coaxial. D) Assemble and connect, connect the first segment and the second segment through the tenon head and the tenon hole, wherein the tenon head and the tenon hole are inserted and in clearance fit. E) Tension construction, pass prestressing tendons through the reserved prestressing ducts, install gaskets and anchorages at both ends and tension the prestressing tendons.

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