Concrete dowel assembly and method of construction thereof

Abstract

The application provides a concrete anchor group, relates to the technical field of concrete construction, and comprises a plurality of anchor pieces arranged side by side, any anchor piece comprises a shank, a base arranged at the bottom of the shank and a bifurcated unit arranged on the shank, and the bifurcated units of any adjacent anchor pieces are staggered. The application can form a spatial three-dimensional extending anchoring network by arranging a plurality of bifurcated legs with specific included angles, establish multiple reverse engagement nodes in the concrete, change the concrete failure mode from a single cone to a spatial netted interlocking system, eliminate the stress concentration risk, and significantly improve the toughness of the anchoring system formed by the low-strength concrete and the base material. The application provides a construction method of the concrete anchor group, the plurality of anchor pieces are fixed in the concrete in a pre-buried manner, the bifurcated structures of the adjacent anchors form a spatial interlocking effect through directional deflection, break through the group anchor efficiency bottleneck under dense arrangement, and realize synergistic effect under high-density anchoring.

Description

Technical Field

[0001] This invention relates to the field of concrete construction technology, and more specifically, to a concrete stud assembly and its construction method. Background Technology

[0002] In the field of engineering, especially in concrete building structures and bridge engineering, studs are a very common and important anchoring connection component, and can also be used as cast-in-place anchors. Its core function is to firmly connect steel structural members (such as steel beams and steel plates) to the upper reinforced concrete slab (or profiled steel sheet composite floor slab), so that they can work together and share the load (called a composite structure).

[0003] The anchoring effect of the stud depends on the composite mechanical behavior of the steel-concrete interface: (1) Mechanical interlocking force (dominant mechanism): After the stud shank is wrapped by concrete, the resistance is formed by surface friction and the extrusion of concrete on the circumference of the stud. (2) Pull-out bearing capacity: The stud head acts as the "anchor end" to resist the vertical uplift force of the concrete slab relative to the steel member. (3) Bending / shear bearing capacity: When bearing longitudinal shear force and the bending moment generated at the root of the shank, the resistance is mainly provided by the constraint effect of the "anchor end" at the root and the surrounding concrete to prevent interface slippage and bending deformation. (4) Local bearing pressure: The concrete below the stud head bears compressive stress to avoid local crushing failure of the concrete.

[0004] However, traditional cylindrical head studs have no grooves or openings at the head and rely solely on end-face pressure bearing. The stud shank is a smooth cylinder, lacking designs such as threads, ribs, or barbs to enhance mechanical engagement. Under tension, they are prone to debonding from the concrete. Furthermore, traditional studs exhibit significant anchorage degradation under dynamic loads. After fatigue cyclic loading, the slippage at the stud-concrete interface increases significantly, and the engagement force decreases significantly. In other words, the alternating compressive force causes repeated debonding and resetting between the concrete and stud interface, resulting in a significant decrease in anchorage stiffness. Summary of the Invention

[0005] The purpose of this invention is to provide a concrete stud assembly, which consists of several stud members arranged side by side. The stud members can form a three-dimensional spatial anchoring network by setting several bifurcated legs with specific included angles, establishing multiple reverse interlocking nodes in the concrete, changing the concrete failure mode from a unidirectional cone to a spatial network interlocking system, eliminating the risk of stress concentration, and significantly improving the adaptability of low-strength concrete. Another objective of this invention is to provide a construction method for concrete stud assembly, which involves fixing multiple stud components in concrete by pre-embedding. As the bifurcated arms of adjacent stud components interlock in the concrete, a three-dimensional grid structure is formed, creating a multi-dimensional constraint system in the concrete. The bifurcated structure of adjacent studs forms a spatial interlocking effect through directional deflection, breaking through the efficiency bottleneck of group studs under dense arrangement and achieving synergistic efficiency under high-density anchoring.

[0006] The embodiments of the present invention are implemented as follows: In a first aspect, embodiments of this application provide a concrete stud assembly, comprising a plurality of stud members arranged side by side, each stud member comprising a stud body, a base disposed at the bottom of the stud body, and a bifurcated unit disposed on the stud body, wherein the bifurcated units of any adjacent stud members are interleaved. In some embodiments of the present invention, the bifurcation unit includes 4-12 identical bifurcation legs, the bifurcation legs are arranged around the bolt body, and the included angle between any bifurcation leg and the bolt body is 45-60°. Furthermore, the number of forked legs is 8, and the angle between any forked leg and the plug body is 55°; Furthermore, the bottom of the base is also provided with a heat buffer groove, and the bolt body, base and forked leg are integrally formed; Furthermore, the forked legs of any adjacent stud pieces cross each other but do not abut against each other.

[0007] Secondly, embodiments of this application provide a construction method for a concrete stud assembly, which uses the aforementioned stud components and includes the following steps: S1: Draw a positioning diagram. Based on the dimensions of the studs, set several stud positioning points on a straight line. The spacing between any adjacent positioning points is the same, and ensure that the bifurcated units can intersect each other. S2: Based on the positioning diagram in step S1, design the pre-embedded bracket and open positioning holes on the pre-embedded bracket according to the positioning points. S3: Fix the pre-embedded bracket to the construction site, then pass the studs through the positioning holes and fix them to the pre-embedded bracket with bolts; S4: Pour concrete into the embedded bracket, and remove the embedded bracket after pouring.

[0008] Furthermore, in step S1, the distance between any adjacent positioning points is greater than twice the diameter of the stud and less than four times the diameter.

[0009] Furthermore, in step S3, during the fixing process, a level is used to ensure that all the studs are at the same horizontal height.

[0010] Furthermore, in step S4, the pouring process is carried out using a chute for diversion. After the concrete slurry covers the bifurcated legs of the stud, the pouring is stopped, and the stud is corrected for deviation.

[0011] Furthermore, step S4 also includes removing the embedded support after the concrete has initially hardened for 24 hours.

[0012] Compared with the prior art, the embodiments of the present invention have at least the following advantages or beneficial effects: 1. This invention adds a bifurcated unit to the traditional stud and designs the included angle between the bifurcated leg and the stud body to be 45-60°. When the crack extends, it can generate a normal compressive force perpendicular to the crack surface, delay the initiation of the initial crack and the development of the crack, force the crack extension direction to deflect, and transform the original unidirectional main crack, or even through crack (split crack) failure, into a multidirectional micro-crack energy dissipation mode. This induces the formation of a spatial network of micro-cracks inside the concrete, decomposes the concentrated load into multi-level dispersed stress waves, and causes the development of concrete cracks to degenerate from a through main crack to a dispersed micro-crack network, effectively delaying and dispersing the through trend of the main crack, thereby inhibiting the complete formation of the classic failure cone surface. 2. This invention fixes multiple studs into concrete by pre-embedding them. As the bifurcated arms of adjacent studs interlock in the concrete, a three-dimensional grid structure is formed, creating a multi-dimensional constraint system in the concrete. The bifurcated structure of adjacent studs forms a spatial interlocking effect through directional deflection, breaking through the efficiency bottleneck of group studs under dense arrangement and achieving synergistic efficiency under high-density anchoring. Attached Figure Description

[0013] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0014] Figure 1 This is a schematic diagram of the structure of the stud component in an embodiment of the present invention; Figure 2 This is a schematic diagram illustrating the interaction of the stud components in an embodiment of the present invention; Figure 3 This is a schematic diagram illustrating how the stud assembly inhibits crack propagation in an embodiment of the present invention.

[0015] Icons: 1-bolt body; 2-base; 3-forked leg; 4-threaded section. Detailed Implementation

[0016] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0017] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0018] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0019] Example 1 Please refer to Figure 1 This embodiment provides a concrete stud assembly, including several stud members arranged side by side. Each stud member includes a stud body 11, a base 22 located at the bottom of the stud body 11, and a bifurcated unit located on the stud body 1. The bifurcated units of any adjacent stud members are interleaved. Furthermore, in this embodiment, the bolt body 1 is cylindrical, bearing the main axial tensile or compressive force and transferring the load to the anchoring part. The length of the bolt body 1 determines the effective embedding depth of the stud between the connector (such as a steel beam) and the concrete. The upper part of the bolt body 1 is also provided with a threaded section 4, the length of which does not exceed one-third of the length of the bolt body 1. The base 2 is disc-shaped, which can provide a stable starting point for the bifurcation unit, evenly distribute the load transferred from the bolt body 1 to the bifurcation unit, and reduce stress concentration. At the same time, its disc itself also forms a large horizontal resistance surface, increasing the difficulty of direct pull-out. The bifurcation unit is located at one end of the bolt body 1 near the base 2, and includes 4-12 bifurcation legs 3 of the same shape, material, and length. All bifurcation legs 3 are arranged around the bolt body 1, and the included angle between any bifurcation leg 3 and the bolt body 1 is the same, which is 45-60°. Moreover, the starting point of all bifurcation legs 3 is on the same horizontal plane, and the spacing between any adjacent bifurcation legs 3 is exactly the same.

[0020] It should be further explained that when the stud is subjected to external force, the initial cracking of the concrete begins at the base 2 and gradually develops towards the surface of the concrete substrate. Its morphology is usually a radial crack radiating outward from around the stud base 2, and as the load is applied, the cracks develop from finer to coarse cracks that can form a failure cone. According to the European standard ETAG 001, the cone cracks usually extend at an angle of 35-45° (35° is uniformly adopted in the simulation).

[0021] In this embodiment, multiple forked legs 3 are arranged around the anchor body 1 in a divergent topological structure. This multidirectional nature of the forked legs 3 ensures that the stud can provide effective anchoring force when subjected to loads in different directions. Furthermore, the presence of multiple forked legs 3 significantly increases the frictional contact surface between the stud and the concrete. After the concrete hardens, the entire stud is better fixed in the concrete matrix, greatly improving the pull-out resistance of the stud.

[0022] Furthermore, the angle between the bifurcated leg 3 and the anchor body 1 is set to 45-60°, which is perpendicular to the direction of crack extension (or has a certain angular deviation, with a difference of ±10°). This key angle design creates a cross-crack constraint mechanism in the concrete. Specifically, when the crack attempts to extend naturally at a 35° angle, the bifurcated leg 3 at 45-60° generates a normal compressive force perpendicular to the crack surface, forcing the crack extension direction to deflect. The crack will either bypass the bifurcated leg 3 or fork in its path. In this case, the single main crack will decompose into a large number of microcracks, forming a microcrack network. The resulting crack diffusion effect can significantly consume the extension energy, thereby greatly delaying the failure process.

[0023] The geometric parameters of the studs (such as rod length, rod diameter, and the number of bifurcated legs 3) can be adaptively adjusted according to the concrete performance grade and load spectrum characteristics. For situations where load requirements are clearly defined or space is limited, 4-6 bifurcated legs 3 can be selected; while for concrete environments with higher bearing capacity requirements or requiring more uniform stress distribution, the number of bifurcated legs 3 should be greater than 8.

[0024] In addition, under the constraint of the same anchorage depth, increasing the number of studs can significantly optimize the load transfer path, that is, induce the formation of a spatial network of microcracks inside the concrete, effectively delay and disperse the tendency of the main crack to penetrate, thereby inhibiting the complete formation of the classic failure cone.

[0025] As a preferred implementation, the number of forked legs 3 is 8, and the included angle between any forked leg 3 and the bolt body 1 is 55°. This design can ensure that the cross gap between the forked legs 3 between adjacent bolt parts is not too small, and at the same time, it can ensure that the included angle between the forked leg 3 and the crack is close to 90° to the greatest extent, thereby better promoting crack decomposition and forming a spatial network of microcracks, thus significantly delaying the process of failure.

[0026] Furthermore, the bottom of the base 2 is also equipped with a heat buffer groove. The heat buffer groove can be a U-shaped groove with a semi-circular cross-section, a square groove with a rectangular cross-section, a V-shaped groove with a V-shaped cross-section, or a composite groove with a U-shaped bottom and a V-shaped top transition. This can reduce the concentration of thermal stress under welding or high-temperature conditions and effectively solve the hidden dangers of the heat-affected zone during welding. The bolt body 1, base 2, and forked leg 3 are integrally formed; the integral forming process ensures the precision of the entire bolt structure.

[0027] Furthermore, the bifurcated legs 3 of any adjacent stud members intersect but do not abut against each other. Specifically, adjacent bifurcated legs 3 interlock but maintain a certain spacing, which further promotes the formation of a spatial network of microcracks, resulting in a discontinuous honeycomb-like fracture surface in the concrete, rather than the traditional inverted cone shape. In addition, the cooperation between multiple stud members forms a three-dimensional grid structure in the concrete, which evenly distributes the stress borne by the stud members. This can overcome the critical limitation of group anchor efficiency under traditional dense stud conditions (i.e., the key mechanical phenomenon that the load-bearing capacity and stiffness of a single stud decrease due to stress superposition when multiple stud members are densely arranged).

[0028] Example 2 This application provides a construction method for a concrete stud assembly, which uses the stud component described in Embodiment 1, and includes the following steps: S1: Draw a positioning diagram. Based on the dimensions of the sheathed components, set several positioning points for the sheathed components on a straight line, and design a set of sheathed components. The spacing between any adjacent positioning points is the same, and the spacing is greater than twice the diameter of the sheathed component and less than four times the stability radius. Then, according to the needs of the construction site, design multiple sets of identical sheathed components simultaneously, and the spacing between adjacent sheathed components is the same.

[0029] S2: Based on the positioning diagram in step S1, design the embedded bracket of the corresponding size, and open the corresponding number and position of positioning holes on the embedded bracket according to the number and position of positioning points. Each positioning hole is provided with threads to cooperate with the fixing studs. After the design is completed, measure and lay out the lines.

[0030] Among them, the embedded brackets are made of channel steel / angle steel to ensure tensile strength ≥500MPa and bracket stiffness calculation displacement ≤1mm, so as to avoid deformation of the brackets during concrete pouring, which would affect the position of the studs.

[0031] S3: Place the pre-embedded bracket on the construction site, weld and fix the bracket legs to the foundation reinforcement, then add 45° diagonal braces to further fix the bracket, and finally level the top surface using a level to ensure that the standard height deviation is ≤±3mm. After fixing, pass the studs through the positioning holes and fix them to the pre-embedded bracket with bolts; during the fixing process, pay attention to adjusting the position of the forked legs 3 to ensure that the forked legs 3 of adjacent studs are staggered but do not interfere with each other. After fixing, use a level to calibrate and ensure that all studs are at the same horizontal height.

[0032] S4: Pour concrete into the embedded support. The pouring process uses a chute for layered pouring, with each layer ≤500mm. During pouring, avoid direct impact of concrete on the studs. Stop pouring once the concrete completely submerges the bifurcated leg 3 of the stud. Allow the concrete to solidify. During solidification, use jacks to correct any deviations in the studs. After 24 hours of initial concrete hardening, remove the embedded support.

[0033] In summary, the embodiments of the present invention provide a device and method that, by adding a bifurcated unit to the traditional stud and designing the included angle between the bifurcated leg 3 and the stud body 1 to be 45-60°, can generate a normal compressive force perpendicular to the crack surface when the crack extends, forcing the crack extension direction to deflect, transforming the original unidirectional splitting failure into a multidirectional microcrack energy dissipation mode, thereby inducing the formation of a spatial network of microcracks inside the concrete, decomposing the concentrated load into multi-level dispersed stress waves, causing the concrete crack development to degenerate from a penetrating main crack to a dispersed microcrack network, effectively delaying and dispersing the penetrating trend of the main crack, thereby inhibiting the complete formation of the classic failure cone surface; By pre-embedding multiple studs into the concrete, a three-dimensional grid structure is formed due to the interlocking of the bifurcated arms of adjacent studs in the concrete. This creates a multi-dimensional constraint system within the concrete. The bifurcated structures of adjacent studs form a spatial interlocking effect through directional deflection, breaking through the efficiency bottleneck of densely arranged studs and achieving synergistic efficiency under high-density anchoring.

[0034] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A construction method for a concrete stud assembly, characterized in that, Includes the following steps: S1: Draw a positioning diagram. Based on the dimensions of the studs, set several stud positioning points on a straight line. The spacing between any adjacent positioning points is the same, and ensure that the branching units of adjacent studs can intersect each other. The stud assembly includes a stud body, a base located at the bottom of the stud body, and a bifurcated unit located on the stud body; The bifurcation unit includes 4-12 identical bifurcation legs, which are arranged around the bolt body, and the included angle between any bifurcation leg and the bolt body is 45-60°. The bottom of the base is also provided with a heat buffer groove, and the bolt, the base and the forked leg are integrally formed; The forked legs of any adjacent stud member cross each other but do not abut against each other; S2: Based on the positioning diagram described in step S1, design a pre-embedded bracket and open positioning holes on the pre-embedded bracket according to the positioning points. S3: Fix the pre-embedded bracket to the construction site, then pass the stud through the positioning hole and fix it to the pre-embedded bracket by bolt connection; S4: Pour concrete into the embedded support, and remove the embedded support 24 hours after the pouring is completed.

2. The construction method of a concrete stud assembly according to claim 1, characterized in that, In step S1, the distance between any adjacent positioning points is greater than twice the diameter of the stud and less than four times the stabilizing radius.

3. The construction method of a concrete stud assembly according to claim 2, characterized in that, In step S3, during the fixing process, a level is used to ensure that all the studs are at the same horizontal height.

4. The construction method of a concrete stud assembly according to claim 3, characterized in that, In step S4, the pouring process is carried out by using a chute for diversion. After the concrete liquid submerges the bifurcated leg of the stud, the pouring is stopped, and the stud is corrected for deviation.

5. The construction method of a concrete stud assembly according to claim 4, characterized in that, Step S4 also includes removing the embedded support after the concrete has initially hardened for 24 hours.

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