Cantilever beam structure
By adopting a combination of a fastening structure and an expanded anchor bolt in the cantilever structure, the problems of low safety and poor durability of the cantilever structure in the prior art are solved, and the stability and durability of the structure are improved.
Patent Information
- Application Number
- CN202420633553.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-03-29
- Publication Date
- 2025-03-07
- Estimated Expiration
- 2034-03-29
AI Technical Summary
The existing cantilever structures are prone to collapse when the planting ribs or chemical anchor bolts fail, and the planting ribs or chemical anchor bolts have lower safety and poor durability when adding new cantilever structures, and old concrete structures are prone to cracking and damage.
A fastening structure is adopted, including fastening steel bars and fastening steel plates, forming a sling to fix it on the original concrete column, and an expanded base anchor bolt is used, including a conical expanded base body and anchor rod, and the anchor rod is installed through drilling to increase the anchor force.
It effectively improves the safety and durability of the cantilever structure, avoids concrete cracking problems, ensures the stable fixation of anchor bolts, and ensures the reliability and durability of the cantilever beam structure.
Smart Images
Figure CN222576227U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of building structure reinforcement design, in particular to a cantilever beam structure. Background Art
[0002] With the continuous advancement of urban construction, reinforcement engineering is an important project to ensure the safety of buildings. Reinforcement engineering involves the structural transformation and reinforcement of buildings. Under the current trend of urbanization, there is a huge market demand. With the increase in urban population, the number of old buildings has increased sharply, and these buildings have many safety hazards. Therefore, it is very necessary to carry out reinforcement engineering.
[0003] At present, anchoring or chemical anchor bolt technology is a common reinforcement form for newly added concrete cantilever beams. However, as a cantilever structure with a single safety factor, if the anchoring or anchor bolt fails, the structure will collapse, resulting in serious consequences. When anchoring or chemical anchor bolt technology is used in newly added cantilever structures, it has the disadvantages of low safety, poor durability, and easy splitting damage of old concrete structures. Utility Model Content
[0004] The utility model provides a cantilever beam structure to solve the technical problem of how to improve the safety of a newly added cantilever structure and avoid splitting of an original concrete pile.
[0005] An embodiment of the utility model provides a cantilever beam structure, which includes: a fastening structure, the fastening structure includes fastening steel bars and fastening steel plates, the fastening steel bars and the fastening steel plates surround and form a hoop to be fixed on the original concrete column; an expanded bottom type anchor bolt, the expanded bottom type anchor bolt includes a conical expanded bottom body and an anchor rod, the original concrete column has a drill hole, the conical expanded bottom body and a part of the anchor rod are located in the drill hole, and the remaining part of the anchor rod protrudes from the first side surface of the original concrete column; a concrete beam, one end of the concrete beam is connected to the original concrete column and wraps the anchor rod.
[0006] Furthermore, the fastening steel plate is connected to the first side surface, and the fastening structure also includes an angle steel, one side of the angle steel is connected to the second side surface, the second side surface is a surface of the original concrete column opposite to the first side surface, and the fastening steel plate and the angle steel are connected through the fastening steel bar.
[0007] Furthermore, the cantilever beam structure further includes a longitudinal steel bar, and the expanded bottom anchor bolt further includes a connecting sleeve. The longitudinal steel bar, the connecting sleeve and the anchor rod are all provided with threads, and the longitudinal steel bar is connected to the anchor rod through the connecting sleeve.
[0008] Furthermore, the fastening steel bars are arranged in multiple rows in the vertical direction, and the spacing between two adjacent rows of the fastening steel bars is between 90 mm and 110 mm.
[0009] Furthermore, there are multiple bottom-enlarged anchor bolts, and two adjacent connecting sleeves are arranged in a staggered manner.
[0010] Furthermore, a length of a portion of the anchor rod protruding from the first side surface is 5 times the diameter of the anchor rod, and a length of a portion of the anchor rod protruding from the first side surface is 10 times the diameter of the anchor rod.
[0011] Furthermore, each of the connecting sleeves is connected to one of the longitudinal steel bars, and a distance between two adjacent longitudinal steel bars is greater than or equal to 50 mm.
[0012] Furthermore, the farthest distance from the borehole to the first side surface is 12 to 16 times the diameter of the anchor rod.
[0013] Furthermore, the bottom-expanding anchor bolt is a self-expanding anchor bolt, and the conical bottom-expanding body includes a bottom-expanding blade.
[0014] Furthermore, a roughened structure is provided between the concrete beam and the original concrete column.
[0015] The utility model provides a cantilever beam structure, which comprises a fastening structure, an expanded bottom anchor bolt and a concrete beam, wherein the fastening structure comprises fastening steel bars and a fastening steel plate, wherein the fastening steel bars and the fastening steel plate surround and form a hoop to be fixed on an original concrete column; the expanded bottom anchor bolt comprises a conical expanded bottom body and an anchor rod, the original concrete column has a drill hole, the conical expanded bottom body and a part of the anchor rod are located in the drill hole, and the remaining part of the anchor rod protrudes from a first side surface of the original concrete column; one end of the concrete beam is connected to the original concrete column and wraps the anchor rod. By adopting a fastening structure composed of fastening steel bars and fastening steel plates, and surrounding the fastening structure to form a hoop, the fastening structure is used to fix the original concrete column in the form of a hoop, thereby improving the structural stability of the original concrete column. Therefore, when drilling holes in the original concrete column, the concrete splitting problem caused by the original concrete column structure being subjected to stress can be effectively avoided, thereby avoiding the loosening and falling off of the expanded bottom type anchor bolt due to the splitting of the original concrete column, ensuring the stability of the fixation of the expanded bottom type anchor bolt, thereby ensuring the reliability and durability of the new cantilever beam structure formed by fixing the concrete beam on the expanded bottom type anchor bolt. BRIEF DESCRIPTION OF THE DRAWINGS
[0016] Figure 1 A schematic diagram of a cantilever beam structure provided by an embodiment of the utility model;
[0017] Figure 2 for Figure 1 Cross-sectional view of the AA section;
[0018] Figure 3 for Figure 1 Cross-sectional view of the BB part.
[0019] Description of Reference Numerals
[0020] 100. Cantilever beam structure; 110. Fastening structure; 111. Fastening steel bars; 112. Fastening steel plates; 113. Angle steels; 114. Welds; 120. Expanded bottom anchor bolts; 121. Conical expanded bottom body; 122. Anchor rods; 123. Connecting sleeves; 130. Concrete beam; 131. First side surface; 132. Second side surface; 133. Drilling; 140. Longitudinal steel bars; 200. Original concrete column; 300. Original concrete beam; D1. Spacing between fastening steel bars; D2. Length of anchor rods protruding from the first side surface; D3. Spacing between longitudinal steel bars; D4. Maximum distance from drilling to the first side surface. DETAILED DESCRIPTION
[0021] In order to make the purpose, technical solution and advantages of the utility model more clear, the utility model is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the utility model and are not used to limit the utility model.
[0022] The various specific technical features described in the specific embodiments can be combined in any suitable manner without contradiction, for example, different embodiments and technical solutions can be formed by combining different specific technical features. In order to avoid unnecessary repetition, the various possible combinations of the specific technical features in the utility model will not be described separately.
[0023] In the following description, the terms "first\second\..." are only used to distinguish different objects, and do not mean that the objects have the same or related points. It should be understood that the directions "above", "below", "outside" and "inside" are all directions in normal use, and the directions "left" and "right" refer to the left and right directions shown in the corresponding schematic diagrams, which may or may not be the left and right directions in normal use.
[0024] It should be noted that the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprising a ..." does not exclude the presence of other identical elements in the process, method, article or device including the element. The term "connected" includes both direct and indirect connections unless otherwise specified.
[0025] In a specific embodiment, the cantilever beam structure is used for reinforcement and fixation of any type of building. For example, the cantilever beam structure is suitable for reinforcement of above-ground building structures; for example, the cantilever beam structure is suitable for reinforcement of underground space structures. For ease of explanation, the following is an exemplary explanation using the cantilever beam structure being suitable for reinforcement of above-ground building structures as an example.
[0026] To facilitate understanding, we first briefly explain the principle of cantilever beam reinforcement. With the continuous advancement of urban construction, the number of old buildings has increased sharply. There are many safety hazards in old buildings, so old buildings need to be reinforced. Anchor bolts or chemical anchor bolts are common reinforcement methods for newly added concrete cantilever beams. However, as a single safety structure, if the anchor bolts or anchor bolts fail, the cantilever structure will collapse, resulting in serious consequences. When anchor bolts or chemical anchor bolts are used in newly added cantilever structures, they have the disadvantages of low safety, poor durability, and easy splitting damage to old concrete structures. These are mainly reflected in the following points: (1) The structural adhesive used in anchor bolts or chemical anchor bolts is prone to aging and often fails to meet the 50-year structural design service life requirement, which seriously affects the durability of the structure. (2) When anchor bolts or chemical anchor bolts are welded to the steel bars of the cantilever beam, If the construction workers do not operate properly and do not use towels soaked in ice water to wrap the embedded rebars, the structural adhesive will fail due to the increase in temperature; (3) The embedded rebar depth is greatly affected by the construction. In actual construction, due to insufficient technical training of construction workers, the embedded rebar depth often does not reach the designed depth, and it is difficult to detect the embedded rebar depth after the construction is completed, which affects the stress of the structure; (4) When drilling holes in the original concrete structure, it is inevitable to damage the original concrete. If the original concrete is not reinforced, it is easy to cause concrete splitting damage after the steel bars or anchors are implanted, resulting in the steel bars or anchors being pulled out. Based on the above problems, the present application provides a cantilever beam structure.
[0027] In some embodiments, Figures 1 to 3 As shown, the cantilever beam structure 100 includes a fastening structure 110, an expanded bottom anchor bolt 120 and a concrete beam 130. The fastening structure 110 includes a fastening steel bar 111 and a fastening steel plate 112. The fastening steel bar 111 and the fastening steel plate 112 surround and form a hoop to be fixed on the original concrete column 200; the expanded bottom anchor bolt 120 includes a conical expanded bottom body 121 and an anchor rod 122. The original concrete column 200 has a drill hole 230. The conical expanded bottom body 121 and a part of the anchor rod 122 are located in the drill hole 230, and the remaining part of the anchor rod 122 protrudes from the first side surface 210 of the original concrete column 200; one end of the concrete beam 130 is connected to the original concrete column 200 and wraps the anchor rod 122.
[0028] Specifically, the original building structure is reinforced by installing a new cantilever beam structure 100. The structure is first described. The original concrete column 200 is a cubic structure. The side of the original concrete column 200 is connected and fixed to the original concrete beam 300. The fastening steel plate 112 is attached to the side and corner of the original concrete column 200. The fastening steel bars 111 pass through the original concrete beam 300 and are respectively connected to the fastening steel plates 112 by welding. Therefore, the fastening steel plate 112 and the fastening steel bars 111 are combined to form a hoop fixed on the original concrete column 200. A borehole 230 is provided in the original concrete column 200, and a bottom-enlarged anchor bolt 120 is installed in the borehole 230. The bottom-enlarged anchor bolt 120 includes a conical bottom-enlarged body 121 and an anchor rod 122. The conical bottom-enlarged body 121 and the anchor rod 122 are connected. The conical bottom-enlarged body 121 and the concrete are squeezed to generate an anchoring force. Compared with the anchoring force of the embedded steel bar or the chemical anchor bolt, the anchoring force is generally increased by 1.5 to 2 times. The bottom-enlarged anchor bolt 120 can obtain a higher bearing capacity and cause less damage to the structure of the original concrete. The conical bottom-enlarged body 121 is completely located in the borehole 230, and part of the anchor rod 122 is also located in the borehole 230. The rest of the anchor rod 122 protrudes from the first side surface 210 of the original concrete column 200. The anchor rod 122 protruding from the original concrete column 200 has a concrete beam 130. The anchor rod 122 and the concrete beam 130 are combined to form a new cantilever concrete beam.
[0029] The bottom-expanding anchor bolt 120 forms an anchoring effect by locking the key between the bottom expansion hole of the drill hole 230 and the anchor bolt assembly. The bottom-expanding anchor bolt 120 can be a self-expanding anchor bolt or a molded bottom-expanding anchor bolt. For example, the bottom-expanding anchor bolt 120 is a self-expanding anchor bolt. The conical bottom-expanding body 121 includes an expansion sleeve and a bottom-expanding cutter head. The material of the bottom-expanding anchor bolt 120 is Q235 or Q345. The thickness of the expansion sleeve is usually 4 to 8 mm. When the diameter of the anchor rod 122 is less than 14 mm, its thickness is 4 mm; when the diameter of the anchor rod 122 is 16 to 22 mm, its thickness is 6 mm; when the diameter of the anchor rod 122 is greater than 22 mm, its thickness is 8 mm. The maximum diameter of the bottom-expanding cutter head is generally the straight hole diameter plus 8 mm. The diameter, quantity, and position of the anchor rod 122 need to be consistent with the steel bars of the newly added concrete beam.
[0030] The borehole 230 is a straight hole at the front end and an enlarged hole at the rear end. The straight hole is connected to the first side surface 210. The diameter of the straight hole is the sum of 2 times the wall thickness of the expansion sleeve and the diameter of the anchor rod. The diameter of the enlarged hole is generally the diameter of the straight hole plus 8 mm. The farthest distance from the borehole 230 to the first side surface 210 is defined as D4. The farthest distance D4 from the borehole 230 to the first side surface 210 is 12 to 16 times the diameter of the anchor rod 122. For example, the farthest distance D4 from the borehole 230 to the first side surface 210 is 15 times the diameter of the anchor rod 122.
[0031] The technical principle of this structural design is as follows: the cantilever concrete beam bears the constant load and live load transmitted from the upper structural plate. After the cantilever concrete beam is subjected to force, pressure and tension are generated simultaneously. The pressure is borne by the concrete and transmitted to the original concrete column 200, while the tension is borne by the longitudinal reinforcement 140 of the beam, and then transmitted to the expanded bottom anchor bolt 120 by the connecting sleeve 123. The expanded bottom anchor bolt 120 is then transmitted to the column through the locking key with the original concrete column 200. The fastening steel bars 111 and the fastening steel plates 112 reinforce the original concrete column 200 through the hoop effect formed to prevent it from splitting and damage, thereby improving the durability and safety of the structure, ensuring the quality of construction, improving the efficiency of construction, ensuring the safety and normal performance of the building, and creating good economic and social benefits.
[0032] For ease of understanding, the construction steps are briefly described below. First, in order to ensure the stability of the connection between the fastening structure 110 and the original concrete column 200, the paint layer on the surface of the component should be chiseled off to expose the concrete base before pasting the fastening steel plate 112. The defective parts of the concrete should be repaired as required, and the oil and slurry on the concrete surface should be removed and polished to a solid base. The uneven parts should be polished or repaired, and the surface dust should be removed and cleaned. Subsequently, the fastening steel plate 112 is polished and rust-removed, and cleaned to ensure that the gap between the fastening steel plate 112 and the concrete base is reasonable, for example, the gap is 3 mm. The fastening steel plate 112 and the original concrete column 200 are connected using structural adhesive, and the density is not less than 90%.
[0033] At the same time, according to the diameter and position of the fastening steel bar 111, a common drill is used to drill holes at the corresponding positions of the original concrete beam 300, and the fastening steel bar 111 is passed through the hole and welded to the fastening steel plate 112. The weld should meet the requirements of the secondary weld, and the weld size and welding quality should meet the requirements of the specification. After welding, the hole is filled with grouting material, and the strength of the grouting material is not less than the strength of C50 to ensure the density of the hole and the connection between the fastening steel bar 111 and the original concrete beam 300.
[0034] It should be emphasized that the installation of the bottom-enlarged anchor bolt 120 can be carried out on the original concrete column 200 only after the grouting of the original concrete beam 300 has been completed for more than 24 hours. The process of drilling the hole 230 is as follows: (1) Drilling a horizontal straight hole: According to the different hole diameters, use an electric hammer, a pneumatic pick or a water drill to drill a straight hole to the designed depth; (2) Enlarging the hole: After cleaning the hole, use an enlarging cone drill bit that matches the hole diameter of the straight hole to enlarge the hole so that the enlarging drill bit stroke meets the specified requirements; (3) Cleaning the hole: Remove the powder and water in the hole; (4) Testing: Use a hole measuring instrument to measure the diameter of the enlarged hole and record it. If it does not meet the requirements, continue to enlarge the hole; (5) Installation: Insert the anchor rod with a clean surface treatment into the bottom of the hole as soon as possible and mark it. (6) Testing: The pull-out bearing capacity of the anchor rod should be tested according to the specifications. Only after the test is qualified can the next step be carried out. Finally, pour the micro-expansion concrete. After the concrete is poured, it should be sprinkled with water for curing. The curing time should be no less than 28 days. The formwork can be removed only after the concrete reaches the designed strength. The structure and construction steps effectively solve the problem of concrete splitting when the structure is stressed, so that the expanded bottom anchor bolt 120 will not be pulled out due to the splitting of the original concrete column 200, ensuring the safety and reliability of the structure.
[0035] The utility model provides a cantilever beam structure, which comprises a fastening structure, an expanded bottom anchor bolt and a concrete beam, the fastening structure comprises fastening steel bars and a fastening steel plate, the fastening steel bars and the fastening steel plate surround and form a hoop to be fixed on an original concrete column; the expanded bottom anchor bolt comprises a conical expanded bottom body and an anchor rod, the original concrete column has a drill hole, the conical expanded bottom body and a part of the anchor rod are located in the drill hole, and the remaining part of the anchor rod protrudes from the first side surface of the original concrete column; one end of the concrete beam is connected to the original concrete column and wraps the anchor rod. By adopting a fastening structure composed of fastening steel bars and fastening steel plates, and surrounding the fastening structure to form a hoop, the fastening structure is used to fix the original concrete column in the form of a hoop, thereby improving the structural stability of the original concrete column. Therefore, when drilling holes in the original concrete column, the concrete splitting problem caused by the original concrete column structure being subjected to stress can be effectively avoided, thereby avoiding the loosening and falling off of the expanded bottom type anchor bolt due to the splitting of the original concrete column, ensuring the stability of the fixation of the expanded bottom type anchor bolt, thereby ensuring the reliability and durability of the new cantilever beam structure formed by fixing the concrete beam on the expanded bottom type anchor bolt.
[0036] In some instances, such as Figure 1As shown, the fastening steel plate 112 is connected to the first side surface 210, and the fastening structure 110 further includes an angle steel 113. One side of the angle steel 113 is connected to the second side surface 220. The second side surface 220 is a side of the original concrete column 200 opposite to the first side surface 210. The fastening steel plate 112 and the angle steel 113 are connected by the fastening steel bar 111. Specifically, in order to further enhance the stability of the fastening structure 110 surrounding the original concrete column 200, and considering that the number of original concrete beams 300 connected to different original concrete columns 200 is different, and to avoid interference problems, the fastening structure 110 further includes an angle steel 113, which is arranged on the inner side of the original concrete column 200, and the fastening steel plate 112 is arranged on the outer side of the original concrete column 200. The outer side here is the first side surface 210, and the inner side can be understood as the side opposite to the first side surface 210. Angle steel 113 is made of hot-rolled equilateral angle steel, which is bonded to the original concrete column 200 by structural adhesive. The corners of the original concrete column 200 should be rounded before the angle steel 113 is bonded. The material of angle steel 113 can be Q235, Q345, Q390, that is, the compressive strength is 235 MPa, 345 MPa, and 390 MPa respectively. Its thickness is generally 8 mm and 10 mm, and its width is 120 mm and 150 mm. Its model can be L50X4, L56X5, and L60X5, and its length is consistent with the cross-sectional height of the newly added cantilever concrete beam. The fastening steel plate 112 and the angle steel 113 are connected by the fastening steel bar 111, and there is a weld 114 between the fastening steel bar 111 and the angle steel 113, and the weld 114 is double-sided welded.
[0037] In some embodiments, Figure 1As shown, considering the length of the cantilever beam structure 100, the cantilever beam structure 100 also includes a longitudinal steel bar 140, and the expanded bottom anchor 120 also includes a connecting sleeve 123. The longitudinal steel bar 140, the connecting sleeve 123 and the anchor rod 122 are all provided with threads, and the longitudinal steel bar 140 is connected to the anchor rod 122 through the connecting sleeve 123. Specifically, the number of connecting sleeves 123 is consistent with the number of anchor rods 122. The connecting sleeves 123 are installed on the exposed anchor rods 122 of the expanded bottom anchor bolts 120, and then the longitudinal reinforcement 140 is installed on the other end of the connecting sleeve. The anchor rods 122 and the longitudinal reinforcement 140 are connected together by a torque wrench. The longitudinal reinforcement 140, the connecting sleeves 123 and the anchor rods 122 are all provided with threads to increase the tightness of the connection between the connecting sleeves 123 and the longitudinal reinforcement 140 and the anchor rods 122. The material of the connecting sleeves 123 is Q235 or Q345, and its diameter is the diameter of the anchor rod 122 plus 6 mm, and its length is 3 times the diameter of the longitudinal reinforcement 140. At the same time, the connection method using the connecting sleeves 123 is convenient to operate, has a good connection position quality, and has high construction efficiency compared to traditional welding. After the longitudinal reinforcement 140 is installed, the formwork can be supported according to the design drawings, and then the micro-expansion concrete can be poured. After pouring concrete, it should be watered and cured for no less than 28 days. The formwork can only be removed after the concrete reaches the designed strength.
[0038] In some embodiments, in combination Figure 1 and Figure 2 As shown, the fastening steel bars 111 are arranged in multiple rows in the vertical direction, and the spacing between two adjacent rows of fastening steel bars 111 is between 90 mm and 110 mm. Specifically, in order to enhance the stability of the connection of the fastening steel bars 111, the fastening steel bars 111 are set as a multi-row structure, and the spacing between two adjacent rows of fastening steel bars 111 is defined as D1, which is between 90 mm and 110 mm. The specific value is not limited. The number of rows arranged can be determined according to the height of the newly added cantilever concrete beam section. For example, the spacing D1 between two adjacent rows of fastening steel bars 111 is 90 mm, 100 mm or 110 mm. The transverse steel bars are HRB400 grade hot-rolled ribbed steel bars with a diameter of 16, which play the role of replacing the stirrups of the column and constraining the original concrete column. After passing through the original concrete beam, they are welded to the fastening steel plate 112 and the angle steel 113 on both sides.
[0039] In some embodiments, Figure 1As shown, in order to enhance the stability of the structure, the number of the expanded bottom anchor bolts 120 is multiple, and two adjacent connecting sleeves 123 are arranged in a staggered manner. The length of the anchor rod 122 protruding from the first side surface 210 is defined as D2. For example, when the number of the expanded bottom anchor bolts 120 is 2, the length of the anchor rod 122 protruding from the first side surface 210 is D2, which is 5 times the diameter of the anchor rod 122; for example, when the number of the expanded bottom anchor bolts 120 is greater than 2, in order to avoid that the connection joints of the anchor rod 122 and the longitudinal reinforcement 140 of the newly added cantilever beam are all set at the same position, two adjacent connecting sleeves 123 are arranged in a staggered manner, and the length D2 of some number of anchor rods 122 protruding from the first side surface 210 is 5 times the diameter of the anchor rod 122, and the length D2 of some number of anchor rods 122 protruding from the first side surface 210 is 10 times the diameter of the anchor rod 122.
[0040] In some embodiments, Figure 1 As shown, each connecting sleeve 123 is connected to a longitudinal steel bar 140, and the spacing between two adjacent longitudinal steel bars 140 is greater than or equal to 50 mm. The specific longitudinal steel bar 140 is the stress-bearing steel bar of the newly added concrete beam. In order to ensure the stability of the structure and avoid the longitudinal steel bars 140 being installed too closely, the longitudinal steel bars 140 can be divided into upper longitudinal steel bars and lower longitudinal steel bars. The upper longitudinal steel bars and the lower longitudinal steel bars are both HRB400 grade hot-rolled ribbed steel bars. The longitudinal steel bars 140 can be arranged in one row or two or three rows, and their total area needs to be determined according to the stress conditions of the cantilever beam in the actual engineering design. The margin between the longitudinal steel bar 140 and the newly added concrete beam should be greater than 6 times the diameter of the longitudinal steel bar 140, the spacing between the two longitudinal steel bars 140 should be greater than 6 times the diameter of the longitudinal steel bar 140, the spacing between the two adjacent longitudinal steel bars 140 is defined as D3, and the spacing D3 between the two adjacent longitudinal steel bars 140 is greater than or equal to 50 mm. For example, when the number of rows of the longitudinal steel bars 140 does not exceed 2, the spacing between each row of the longitudinal steel bars 140 should be greater than or equal to 50 mm; for example, when the number of rows of the longitudinal steel bars 140 exceeds 2, the spacing between each row of the longitudinal steel bars 140 should be greater than or equal to 75 mm.
[0041] In some embodiments, Figure 1As shown, there is a roughening structure between the concrete beam 130 and the original concrete column 200. Specifically, the concrete beam 130 is a concrete mixed with an expansion agent, which is used to cast the newly added cantilever concrete beam. Its limited expansion rate should be greater than or equal to 0.015, the amount of cementitious material should be greater than or equal to 300kg / m3, the coarse aggregate particle size of the micro-expansive concrete is less than 30 mm, and medium sand is used. The amount per cubic meter ranges from 0.38 to 0.41. It should be poured continuously with an interval of less than 60 minutes. Retarder can be added according to actual conditions. The strength grade of micro-expansive concrete can be selected as C30, that is, the compressive strength is not less than 14.3 MPa. The roughening treatment between the concrete beam 130 and the original concrete column 200 forms a roughening structure so that the concrete beam 130 and the original concrete column 200 can be tightly combined.
[0042] The above description is only a preferred embodiment of the present invention and is not intended to limit the protection scope of the present invention.
Claims
1. A cantilever beam structure, characterized in that: include: A fastening structure, the fastening structure comprising fastening steel bars and fastening steel plates, the fastening steel bars and the fastening steel plates surround and form a hoop fixed on the original concrete column; An expanded bottom anchor bolt, the expanded bottom anchor bolt comprising a conical expanded bottom body and an anchor rod, the original concrete column having a drill hole, the conical expanded bottom body and a portion of the anchor rod being located in the drill hole, and the remaining portion of the anchor rod protruding from a first side surface of the original concrete column; A concrete beam, one end of which is connected to the original concrete column and wraps the anchor rod.
2. The cantilever beam structure according to claim 1, characterized in that: The fastening steel plate is connected to the first side surface, and the fastening structure also includes an angle steel. One side of the angle steel is connected to the second side surface, and the second side surface is a side of the original concrete column opposite to the first side surface. The fastening steel plate and the angle steel are connected through the fastening steel bar.
3. The cantilever beam structure according to claim 2, characterized in that: The cantilever beam structure further includes a longitudinal steel bar, and the expanded bottom anchor bolt further includes a connecting sleeve. The longitudinal steel bar, the connecting sleeve and the anchor rod are all provided with threads, and the longitudinal steel bar is connected to the anchor rod through the connecting sleeve.
4. The cantilever beam structure according to claim 3, characterized in that: The fastening steel bars are arranged in multiple rows in the vertical direction, and the spacing between two adjacent rows of the fastening steel bars is between 90 mm and 110 mm.
5. The cantilever beam structure according to claim 3, characterized in that: There are multiple bottom-enlarged anchor bolts, and two adjacent connecting sleeves are arranged alternately.
6. The cantilever beam structure according to claim 5, characterized in that: The length of a portion of the anchor rod protruding from the first side surface is 5 times the diameter of the anchor rod, and the length of a portion of the anchor rod protruding from the first side surface is 10 times the diameter of the anchor rod.
7. The cantilever beam structure according to claim 5, characterized in that: Each of the connecting sleeves is connected to one of the longitudinal steel bars, and the distance between two adjacent longitudinal steel bars is greater than or equal to 50 mm.
8. The cantilever beam structure according to claim 1, characterized in that: The farthest distance from the drill hole to the first side surface is 12 to 16 times the diameter of the anchor rod.
9. The cantilever beam structure according to claim 1, characterized in that: The bottom-expanding anchor bolt is a self-expanding anchor bolt, and the conical bottom-expanding body includes a bottom-expanding blade.
10. The cantilever beam structure according to claim 1, characterized in that: A roughened structure is provided between the concrete beam and the original concrete column.