High-bite performance ribbed steel bar and its manufacturing roll

Abstract

The utility model relates to a reinforcing bar field discloses a high bite performance ribbed reinforcing bar, is equipped with vertical rib and a plurality of horizontal ribs on reinforcing bar, is equipped with a plurality of vertical rib horizontal teeth on vertical rib side, and vertical rib horizontal teeth and horizontal rib are set up along the longitudinal direction staggeredly, a kind of high bite performance ribbed reinforcing bar preparation roll, including the same structure, the upper preparation roll and the lower preparation roll of opposite rotation direction, the upper preparation roll and the lower preparation roll are all equipped with forming groove in circumference, each forming groove inner wall is equipped with the horizontal rib groove and the horizontal tooth groove corresponding with the horizontal rib of high bite performance ribbed reinforcing bar and vertical rib horizontal tooth respectively, and horizontal tooth groove is set between adjacent horizontal rib groove. Above together constitute finished product preparation pass, and the required reinforcing bar rib is rolled out when preparing, to improve rib nature, and actively promote reinforcing bar and concrete bite performance.

Description

Technical Field

[0001] This utility model relates to the field of reinforcing bars, specifically to a ribbed reinforcing bar with high interlocking performance and its preparation roll. Background Technology

[0002] In the field of building and infrastructure construction, the interlocking strength between ribbed steel bars and concrete (interlocking strength being the main component of bond strength) is a key performance indicator for ensuring the integrity and safety of the structure. However, as modern engineering structures develop towards higher, more complex structures with higher load-bearing requirements, the interlocking performance of existing ribbed steel bars is gradually becoming insufficient to meet the ever-increasing production and construction demands. It is worth noting that there is little research on the rib morphology of ribbed steel bars in my country, and the relevant technical standards for rib patterns have remained unchanged for over forty years.

[0003] Currently, due to insufficient interlocking performance between ribbed steel bars and concrete, the following main problems exist:

[0004] 1. The use of high-strength steel bars is restricted, resulting in low economic and social benefits and difficulty in guaranteeing project quality:

[0005] In large-span, heavy-load, earthquake-resistant, and long-life engineering projects, especially in my country's transportation construction sector, entry-level HRB400 steel bars are almost universally used, while HRB500 and HRB600 high-strength steel bars are rarely applied, especially in transportation construction projects in mountainous areas where bridges and tunnels account for a large proportion. The reason for this is that while the application of high-strength steel bars can theoretically reduce cross-sectional area and save materials, the reduced contact area between steel and concrete leads to a decrease in the interlocking force, resulting in reduced load-bearing capacity and excessively wide cracks, making it a practically undesirable choice for engineers. However, in advanced countries abroad, the widespread use of HRB500 and HRB600 high-strength steel bars has yielded significant economic and social benefits. Furthermore, the use of lower-grade steel bars results in high reinforcement ratios, especially at stress-prone joints, where excessively dense reinforcement makes it difficult to guarantee the quality of concrete pouring, posing a safety hazard and becoming a pain point in my country's engineering industry.

[0006] Passively improving interlocking performance by adopting structural design and construction techniques sacrifices cost and efficiency, and quality cannot be guaranteed: increasing stirrups, increasing the thickness of concrete cover, increasing the spacing of steel bars, increasing concrete strength, and passively improving interlocking performance by vibrating the concrete to make it self-compact.

[0007] However, such improvements have reached their limits. On the one hand, these improvements require sacrificing cost and construction efficiency. On the other hand, once the improvement parameters are increased to a certain extent, the increase in interlocking force becomes smaller and smaller, and the quality has a certain degree of uncertainty, which may reduce the safety of the structure.

[0008] Relying on imported high-performance steel bars increases project costs and hinders technological progress. For high-requirement buildings, directly purchasing advanced high-performance steel bar products from abroad is a viable solution. While this can quickly meet performance requirements, the high price of imported products significantly increases project costs and hinders the accumulation of technology and independent development in related domestic industries.

[0009] Based on the above-mentioned engineering pain points, we urgently need a high-interlocking-force steel bar that can proactively improve interlocking performance through ribbed design, thereby contributing to the iterative upgrading of engineering technology in my country. Utility Model Content

[0010] The present invention aims to provide a ribbed steel bar with high interlocking performance, which actively improves the interlocking performance through the inherent improvement of the rib pattern.

[0011] To achieve the above objectives, the present invention adopts the following technical solution: a ribbed steel bar with high interlocking performance, comprising a steel bar base circle, on which longitudinal ribs and several transverse ribs are provided, and on the side of the longitudinal ribs are several longitudinal rib transverse teeth, and the longitudinal rib transverse teeth and transverse ribs are arranged alternately along the longitudinal direction.

[0012] The research and development approach for this solution is as follows:

[0013] 1. In the existing technologies for increasing interlocking force, all of them are external improvements that are detached from the steel bar itself. Moreover, after the improvement parameters are increased to a certain extent, the improvement on interlocking force becomes smaller and smaller. Therefore, the inventor of the utility model decided to improve from the perspective of the steel bar itself and directly enhance the interlocking strength.

[0014] First, the projected area of ​​the longitudinal rib or transverse rib along the longitudinal direction of the steel bar is the longitudinal projected area. The interlocking strength is positively correlated with the longitudinal projected area of ​​the structure. In the prior art, the transverse ribs of the ribbed steel bars usually form a certain angle with the axis. The longitudinal projected area of ​​the transverse rib is smaller than the area of ​​the transverse rib itself. Therefore, the area of ​​the transverse rib itself is not fully utilized to maximize the interlocking strength.

[0015] 2. The inventor discovered that in the prior art, the transverse ribs of the ribbed steel bar are crescent-shaped ribs, and there is a gap between them and the longitudinal ribs (this type of rib is easy to process and not easy to jam the roller). Therefore, the gap position is relatively smooth and is comparable to the surface of the plain round steel bar. It cannot generate a biting force on the concrete structure, and the concrete cannot effectively transfer the stress to the steel bar at this position, resulting in insufficient overall biting force.

[0016] 3. This design improves upon the existing rib pattern while also meeting the requirements of current specifications and aligning with existing parameter data as closely as possible. The original crescent ribs are retained, complying with the provisions of standard GB 1499.2-2024 "Steel for Reinforced Concrete - Part 2: Hot-rolled Ribbed Steel Bars".

[0017] Therefore, this solution has the following effects: by making full use of the gap between the transverse and longitudinal ribs and adding transverse teeth to the longitudinal ribs, the longitudinal projected area is maximized, thereby significantly increasing the biting performance, with a maximum increase of 27.5%.

[0018] Furthermore, the included angle between the transverse rib and the circular axis of the reinforcing bar is 60°-90°.

[0019] Furthermore, the included angle between the longitudinal rib transverse teeth and the circular axis of the reinforcing bar base is 60°-90°.

[0020] Furthermore, the transverse ribs and longitudinal ribs are parallel to each other.

[0021] Furthermore, the included angle between the transverse ribs and the transverse teeth of the longitudinal ribs and the circular axis of the reinforcing bar base is 90°.

[0022] This configuration increases the angle between the transverse rib and the circular axis of the reinforcing bar. While keeping the longitudinal projected area unchanged, the extra area forms the transverse teeth of the longitudinal rib, further increasing the longitudinal projected area, thereby increasing the longitudinal force-bearing area and improving the interlocking performance.

[0023] Furthermore, the transverse ribs are all crescent-shaped.

[0024] Furthermore, the morphology of the longitudinal ribs and transverse teeth is 1 / 2 crescent shape. 1 / 2 crescent shape means that the complete crescent shape is divided into two symmetrical halves by the central axis, and one half is the 1 / 2 crescent shape.

[0025] Furthermore, the base circle of the reinforcing bar is provided with four rows of longitudinal ribs and transverse teeth, and the longitudinal cross-sectional area F of one longitudinal rib and transverse tooth is... R2 The calculation formula is:

[0026] F R2 = F R0 ×(1-sinβ0) / 2;

[0027] F R0 -Longitudinal cross-sectional area of ​​standard reinforcing bars;

[0028] β0 - The angle between the transverse ribs of the standard steel bar and the axis of the base circle of the steel bar.

[0029] Furthermore, the formula for calculating the relative rib area of ​​the reinforcing bar is:

[0030] f r =( K1×F R1 ×sinβ1) / (π×d×l)+φ×( K2×F R2 ×sinβ2) / (π×d×l);

[0031] K1 - Number of horizontal rib rows;

[0032] F R1- The longitudinal cross-sectional area of ​​a transverse rib; the longitudinal cross-sectional area of ​​an object refers to the cross-sectional area perpendicular to the thickness direction of the object.

[0033] β1 - The angle between the transverse rib and the circular axis of the reinforcing bar base;

[0034] d - Nominal diameter of the reinforcing bar;

[0035] l - Spacing between transverse ribs;

[0036] K2 - Number of rows of longitudinal ribs and transverse teeth;

[0037] F R2 - The longitudinal cross-sectional area of ​​a longitudinal rib and transverse tooth;

[0038] β2 - The angle between the longitudinal rib transverse tooth and the circular axis of the reinforcing bar base;

[0039] φ - the area reduction factor of the longitudinal rib and transverse tooth, which is 0.85-0.95.

[0040] Among them, the four rows of longitudinal ribs and transverse teeth refer to: there are two longitudinal ribs on the base circle of the steel bar, and longitudinal rib transverse teeth are provided on both sides of one longitudinal rib. The row of longitudinal ribs and transverse teeth refers to the transverse teeth of the longitudinal rib on one side of the longitudinal rib.

[0041] By increasing only the angle between the transverse rib and the axis, the volume of the transverse rib in this solution is smaller than that of the transverse rib in the prior art. The volume saved can be transferred to the gap between the transverse rib and the longitudinal rib to form the transverse teeth of the longitudinal rib, which enhances the biting force at this position and allows the circumferential biting effect to be fully exerted. At the same time, the longitudinal cross-sectional area and the overall volume remain unchanged before and after the rib pattern changes.

[0042] In this scheme, the relative rib area of ​​the reinforcing bars is calculated using a formula to facilitate comparison with existing reinforcing bars and enable equivalent replacement for industrial upgrading. The number of transverse rib rows refers to the number of transverse ribs per unit length of the reinforcing bar, usually K1=2; similarly, the number of longitudinal rib teeth rows refers to the number of longitudinal rib teeth per unit length of the reinforcing bar, usually K2=4.

[0043] The present invention aims to provide a high-interlocking-performance ribbed steel bar preparation roll for producing a high-interlocking-performance ribbed steel bar.

[0044] To achieve the above objectives, this utility model adopts the following technical solution: a high-interlocking-performance ribbed steel bar preparation roll, comprising an upper preparation roll and a lower preparation roll with identical structures but opposite rotation directions. Both the upper and lower preparation rolls are circumferentially provided with forming grooves. The inner wall of each forming groove is provided with transverse rib grooves and transverse tooth grooves corresponding to the transverse ribs and longitudinal rib teeth of the high-interlocking-performance ribbed steel bar, respectively. The transverse tooth grooves are located between adjacent transverse rib grooves. All of these together form the finished product preparation die, which rolls the required steel bar ribs (transverse ribs and longitudinal rib teeth) during preparation.

[0045] This design, with crescent-shaped grooves for the transverse ribs and half-crescent-shaped grooves for the transverse teeth, creates a smooth transition between the two, minimizing stress concentration in the resulting ribs. Furthermore, the crescent-rib design reduces the likelihood of roll jamming during rolling, resulting in smoother production. In contrast, other rib designs, such as spiral-ribbed steel bars, may present more technological challenges during production, while the crescent-rib design helps improve production efficiency and product quality stability.

[0046] The transverse ribs and longitudinal rib teeth are the main structures that provide interlocking force. During rolling, as much metal as possible needs to be pressed into the grooves. However, the part between the two ends is not easily squeezed and is difficult to fill effectively. In this solution, since the transverse rib grooves and transverse tooth grooves are crescent-shaped or 1 / 2 crescent-shaped, the surrounding metal is more easily pressed into the transverse rib grooves and transverse tooth grooves, thereby ensuring the density and strength of the transverse ribs and longitudinal rib teeth and ensuring the reliability of the reinforcing bar ribs under stress.

[0047] Even under long-term overload conditions, the longitudinal ribs and transverse teeth, acting as auxiliary structures, preferentially deform and absorb energy, transferring more load to the longitudinal ribs through the transverse teeth. This reduces the load on the transverse ribs and enhances the overall structural durability.

[0048] The horizontal ribs and longitudinal ribs are arranged in an alternating pattern, so that the part where the concrete and steel bars meet is arranged in an S-shape between the horizontal ribs and longitudinal ribs, which greatly increases the contact area between the concrete and steel bars and further enhances the interlocking effect. Attached Figure Description

[0049] Figure 1 This is a three-dimensional diagram of Example 1;

[0050] Figure 2 This is the front view of Example 1;

[0051] Figure 3 This is a top view of Example 1;

[0052] Figure 4 This is the front view of Example 2;

[0053] Figure 5 This is a three-dimensional diagram of the rolls prepared in Example 2. Detailed Implementation

[0054] The following detailed description illustrates the specific implementation methods:

[0055] The reference numerals in the accompanying drawings include: 1. Reinforcing bar base circle; 2. Longitudinal rib; 3. Transverse rib; 4. Longitudinal rib transverse tooth; 51. Upper preparation roll; 52. Lower preparation roll; 53. Forming groove; 54. Transverse tooth groove; 55. Transverse rib groove.

[0056] Example 1

[0057] Example 1 is basically as follows Figures 1-3 As shown: A high-interlocking-performance ribbed steel bar includes a steel bar base circle 1. In this design, the steel bar base circle 1 refers to a cylindrical base. Two longitudinal ribs 2 and several transverse ribs 3 are integrally formed on the steel bar base circle 1. The transverse ribs 3 are arranged in two rows between the two longitudinal ribs 2. A gap is left between the end of each transverse rib 3 and the longitudinal rib 2. The transverse ribs 3 are crescent-shaped ribs. The angle between the transverse ribs 3 and the axis of the steel bar base circle 1 is 90°, that is, perpendicular to the axis of the steel bar base circle 1.

[0058] The longitudinal rib 2 has several longitudinal rib transverse teeth on its side. The transverse rib 3 is parallel to the longitudinal rib transverse teeth. The longitudinal rib transverse teeth are arranged in pairs between adjacent transverse ribs. In this embodiment, the longitudinal rib transverse teeth 4 is a 1 / 2 crescent-shaped structure. One end of the longitudinal rib transverse teeth 4 is integrally formed with the longitudinal rib 2, and the other end extends to the space between two adjacent transverse ribs 3. That is, there is a partial overlap between the vertical projection of the longitudinal rib transverse teeth 4 and the transverse rib 3 on the axis of the steel base circle 1. That is, the longitudinal cross-sectional area F of the longitudinal rib transverse teeth is... R2 The calculation formula is:

[0059] F R2 = F R0 ×(1-sinβ0) / 2;

[0060] F R0 -Longitudinal cross-sectional area of ​​standard reinforcing bars;

[0061] β0 - The angle between the transverse rib of the standard steel bar and the axis of the steel bar base circle. In this embodiment, β0 = 50°.

[0062] The formula for calculating the relative rib area in this case (used to represent bond strength) is as follows:

[0063] f r =(K1×F R1 ×sinβ1) / (π×d×l)+φ×( K2×F R2 ×sinβ2) / (π×d×l);

[0064] K1 - Number of rows of transverse ribs (3 rows). In this embodiment, K1 = 2.

[0065] F R1 - The longitudinal cross-sectional area of ​​a transverse rib 3, in this embodiment, F R1 = F R0 ×sinβ0;

[0066] β1 - The angle between the axis of the transverse rib 3 and the axis of the base circle 1 of the steel bar; in this embodiment, it is taken as 90°;

[0067] d - Nominal diameter of the reinforcing bar base circle 1;

[0068] l- Spacing between transverse ribs;

[0069] K2 - Number of rows of longitudinal rib transverse teeth; in this embodiment, K2 = 4.

[0070] F R2 - The longitudinal cross-sectional area of ​​a longitudinal rib and transverse tooth;

[0071] β2 - The angle between the longitudinal rib transverse tooth and the axis of the base circle 1 of the steel bar; in this embodiment, it is taken as 90°;

[0072] φ - the area reduction factor of the longitudinal rib and transverse tooth, which is 0.85-0.95. In this embodiment, φ=0.9. This data is obtained through laboratory testing.

[0073] Relative rib area in this embodiment ） Substituting the values, we get f. r =(2×F R0 ×sin50°×1)) / (π×d×l)+0.9×(4×F R2 ×1) / (π×d×l)

[0074] Substitute into formula F R2 = F R0 ×(1-sinβ0) / 2;β0=50°

[0075] f r =(2sin50°×F R0 ) / (π×d×l)+0.9×(2F R0 ×(1-sin50°)) / (π×d×l)

[0076] =( 2 sin50°×F R0 +1.8×F R0 -1.8 sin50°×F R0 ) / (π×d×l)

[0077] = F R0 (1.8+0.2sin50°) / (π×d×l)

[0078] Relative rib area of ​​ordinary ribbed steel bars: according to specifications

[0079] f r ‘ =(K1×F R0 ×sinβ0) / (π×d×l);

[0080] Substituting the values, we get f r ‘ = F R0 (2×sin50°) / (π×d×l);

[0081] Therefore, it can be concluded that, compared with ordinary steel bars, the bond strength of this scheme is improved by (f) r / f r‘ )-100%=(1.8+0.2sin50°) / (2×sin50°)-100%=27.5%.

[0082] In practical applications, when the steel reinforcement strength is replaced by HRB500 or HRB600, in order to fully utilize the reinforcement strength, the cross-sectional radius is reduced, the contact area between the reinforcement and concrete is decreased, and the bond strength is reduced. The required average bond stress of the reinforcement can be calculated using the following formula, thus determining the percentage increase in bond strength required (using the average bond stress τ). b (This indicates) that only by compensating for the reduction in adhesion can the following be achieved:

[0083] F=σ s ×A=σ s ×πr 2 ;

[0084] τ b = F / (2πrL)

[0085] F - Maximum pull-out force;

[0086] σ s - The design tensile strengths are 360 ​​MPa, 435 MPa, and 520 MPa for HRB400, HRB500, and HRB600, respectively.

[0087] r - radius of the steel bar section

[0088] L: Calculated length of the reinforcing bar (e.g., embedment length, lap length)

[0089] As shown in the first formula, with the maximum pull-out force remaining constant and fully utilizing the strength of the reinforcing steel, the ratio of the cross-sectional radii corresponding to HRB400, HRB500, and HRB600 is 360. -（1 / 2） :435 -（1 / 2） 520 -（1 / 2） .

[0090] As shown in the second formula, with the maximum pull-out force remaining constant, and due to the change in cross-sectional radius, the calculated ratio of the required bond stress for HRB400, HRB500, and HRB600 is 360. （1 / 2） :435 （1 / 2） 520 （1 / 2） It can be seen that even if HRB400 is replaced with HRB500 or HRB600, the contact area between the steel bar and concrete is reduced, the original bonding force is reduced, and the bonding strength only needs to be increased by 9.9% or 20.2% to compensate, which is far less than the 27.5% increase in bonding strength in this case.

[0091] As can be seen from the above embodiments, the interlocking performance of this solution is significantly improved compared to the original solution, resulting in a comprehensive improvement in the performance of reinforced concrete structures. The specific beneficial effects are as follows:

[0092] 1. Anchorage / lap length is significantly reduced. 2. Concrete crack spacing becomes smaller and denser, and crack distribution becomes more uniform.

[0093] 3. The width of concrete cracks is significantly narrowed, greatly improving usability and durability.

[0094] 4. The stiffness of the components is increased, and the deflection deformation is reduced.

[0095] 5. Ensure that the yield strength of the reinforcing steel is fully utilized to avoid premature failure due to connection failure.

[0096] 6. Improved ductility prevents brittle splitting failure and enhances earthquake resistance.

[0097] 7. Durability is significantly improved. Due to the narrowing of cracks, harmful substances are less likely to penetrate, and the corrosion resistance life of steel bars is extended.

[0098] 8. The fatigue performance of steel bars is significantly improved, reducing repeated slip damage.

[0099] In conclusion, the interlocking performance of reinforced concrete is the core and cornerstone of its collaborative work, and its importance has become a consensus across the industry.

[0100] Example 2

[0101] Example 2 is basically as follows Figure 4 , Figure 5 As shown, a high-interlocking-performance ribbed steel bar preparation roll includes an upper preparation roll 51 and a lower preparation roll 52 with identical structures but opposite rotation directions. Taking the upper preparation roll 51 as an example, the upper preparation roll 51 has a forming groove 53 circumferentially opened. The specific structure of the forming groove 53 is as follows: Figure 5 As shown, the forming groove 53 has a transverse rib groove 55 and a transverse tooth groove 54 perpendicular to the rotation direction of the forming roll in the middle. The transverse tooth groove 54 is arranged between adjacent transverse rib grooves 55, and the end of the transverse tooth groove 54 is connected to the edge of the forming groove 53. In this embodiment, a high-interlocking ribbed steel bar forming roll is used to roll a high-interlocking ribbed steel bar of Example 1.

[0102] The manufacturing of ribbed steel bars involves several pressing processes. In this embodiment, the preparation roll is used in the final finished product process to press out the ribs.

[0103] Example 3

[0104] The difference between Example 3 and Example 1 is that the longitudinal ribs and transverse teeth are strip structures with rectangular cross sections.

[0105] The above descriptions are merely embodiments of this utility model. Commonly known technical solutions and / or characteristics are not described in detail here. It should be noted that those skilled in the art can make various modifications and improvements without departing from the technical solution of this utility model. These modifications and improvements should also be considered within the scope of protection of this utility model, and will not affect the effectiveness of the implementation of this utility model or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. A high-interlocking ribbed steel bar, comprising a base circle of the steel bar, wherein longitudinal ribs and a plurality of transverse ribs are provided on the base circle of the steel bar, characterized in that: The longitudinal ribs are provided with several longitudinal rib teeth on the side, and the longitudinal rib teeth and transverse ribs are arranged alternately along the longitudinal direction.

2. The high-interlocking-performance ribbed steel bar according to claim 1, characterized in that: The angle between the transverse rib and the circular axis of the reinforcing bar is 60°-90°.

3. The high-interlocking-performance ribbed steel bar according to claim 1, characterized in that: The angle between the longitudinal ribs and the transverse teeth and the circular axis of the reinforcing bar is 60°-90°.

4. A ribbed steel bar with high interlocking performance according to any one of claims 2 and 3, characterized in that: The transverse ribs and longitudinal ribs have parallel transverse teeth.

5. A ribbed steel bar with high interlocking performance according to claim 4, characterized in that: The included angle between the transverse ribs and longitudinal rib teeth and the circular axis of the reinforcing bar base is 90°.

6. The high-interlocking-performance ribbed steel bar according to claim 1, characterized in that: The transverse ribs are all crescent-shaped.

7. A ribbed steel bar with high interlocking performance according to claim 1, characterized in that: The longitudinal ribs and transverse teeth are both crescent-shaped.

8. A ribbed steel bar with high interlocking performance according to claim 5, characterized in that: The base circle of the reinforcing bar has four rows of longitudinal ribs with transverse teeth, and the longitudinal cross-sectional area F of one longitudinal rib with transverse teeth is... R2 The calculation formula is: F R2 = F R0 ×(1-sinβ0) / 2; F R0 -Longitudinal cross-sectional area of ​​standard reinforcing bars; β0 - The angle between the transverse ribs of the standard steel bar and the axis of the base circle of the steel bar.

9. A high-interlocking-performance ribbed steel bar according to any one of claims 2 and 3, characterized in that: The formula for calculating the relative rib area of ​​a reinforcing bar is: f r =( K1×F R1 ×sinβ1) / (π×d×l)+φ×( K2×F R2 ×sinβ2) / (π×d×l); K1 - Number of horizontal rib rows; F R1 - The longitudinal cross-sectional area of ​​a transverse rib; β1 - The angle between the transverse rib and the circular axis of the reinforcing bar base; d - Nominal diameter of the reinforcing bar; l - Spacing between transverse ribs; K2 - Number of rows of longitudinal ribs and transverse teeth; F R2 - The longitudinal cross-sectional area of ​​a longitudinal rib and transverse tooth; β2 - The angle between the longitudinal rib transverse tooth and the circular axis of the reinforcing bar base; φ - the area reduction factor of the longitudinal rib and transverse tooth, which is 0.85-0.95.

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