A method for strengthening reinforced concrete beams by rear opening
By using steel casing reinforcement method on reinforced concrete beams and bonding structural adhesive to concrete, the problem of weakening the bearing capacity of the rear hole is solved, and a simple and efficient reinforcement effect is achieved, and the safety of the house is improved.
Patent Information
- Application Number
- CN201911012537.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2019-10-23
- Publication Date
- 2024-12-31
- Estimated Expiration
- 2039-10-23
AI Technical Summary
In reinforced concrete houses, rear openings will weaken the bearing capacity of the beams. The existing reinforcement methods are complex and affect the appearance and lack effective reinforcement measures.
Using the steel casing reinforcement method, drilling out the pipeline to pass through the beam, determining the steel casing size according to the beam width and hole diameter, setting up a head plate and threaded connection, and using high-strength structural adhesive to bond with concrete to ensure the casing and hole wall Close connection to avoid unfull structural adhesive and damage to the hole wall.
It effectively compensates for the weakening of the beam bearing capacity by the rear hole, and simply and efficiently strengthens the bearing capacity of reinforced concrete beams, avoids local damage and structural defects, and improves the overall safety of the house.
Smart Images
Figure CN110700615B_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the field of concrete reinforcement, and in particular to a method for strengthening a reinforced concrete beam by rear-hole drilling. Background Art
[0002] During the construction or use of reinforced concrete houses, it is often encountered that the use function needs to be partially changed. Once the use function changes, the house equipment pipelines that guarantee the function need to be rearranged. Equipment pipelines are generally arranged within the indoor ceiling height so as not to affect the indoor space net height. Once the pipeline layout is adjusted, it often collides with the reinforced concrete floor beams of the house structure in height. Therefore, it is often necessary to open holes in the existing floor beams to pass the pipelines. However, as the main component of the main structure, the reinforced concrete floor beam plays a role in vertical load-bearing and resisting lateral earthquakes and wind loads. Directly opening holes in the existing reinforced concrete beams will significantly weaken the bearing capacity of the beams themselves and affect the overall safety of the house. Unlike the reserved openings and corresponding strengthening measures during the construction of reinforced concrete beams, there is a lack of effective measures to compensate for the adverse effects of the openings on the bearing capacity of the beams. The practice of pasting high-strength fiber materials or steel plates on the outer surface of the beams generally adopted in engineering is complicated to construct and affects the appearance, which easily leaves users with a bad impression that the reinforced structure is defective. Summary of the invention
[0003] In view of the shortcomings of the prior art, the present invention proposes a method for strengthening reinforced concrete beams after opening a hole, which effectively plays a strengthening role by adding a steel casing to compensate for the weakening of the bearing capacity of the beam caused by the opening after opening, making the reinforcement of the reinforced concrete beam after opening a hole more simple and effective.
[0004] The purpose of the present invention is achieved through the following technical solutions:
[0005] A method for strengthening a reinforced concrete beam by rear opening, characterized in that the method specifically comprises the following steps:
[0006] S1: Drill a round hole for the pipeline to pass through the beam as required, clean the hole and paint the surface layer on the side of the beam;
[0007] S2: Determine the size of the reinforced steel casing according to the beam width and the hole diameter, wherein the outer diameter of the steel casing is the hole diameter minus 4-6mm, and the wall thickness is determined based on the principle of equal strength of the beam cross section before and after the hole opening combined with the commonly used specifications of the steel casing; the steel casing is divided into two long and short sections along the hole opening direction, and both sections are provided with a head plate at the outer ends, and a plurality of grooves and bayonet holes are provided on the head plate for rotating the steel casing; the long section and the short section of the steel casing are connected to each other by setting internal and external threads at the junction, the long section of the steel casing adopts external threads, and the long section of the steel casing adopts internal threads;
[0008] S3: Before installing the steel casing, the structural adhesive is brushed on the side wall of the opening, and the structural adhesive is also brushed on the surface of the long section and the short section of the steel casing. The thickness of the structural adhesive is based on filling the gap between the outer wall of the steel casing and the hole wall; the structural adhesive has a bearing capacity higher than the strength of concrete and a slow setting function;
[0009] S4: First, extend the long section of the steel casing coated with structural adhesive into the hole until the head plate presses against the concrete surface of the beam side. Then, on the other side of the hole, extend the short section of the steel casing coated with structural adhesive into the hole. Then, use the groove of the head plate to tighten the connection, and finally ensure that the head plates at both ends of the casing are close to the concrete surface of the beam side.
[0010] S5: Avoid disturbance before the structural adhesive solidifies and hardens. After hardening, the hole reinforcement is completed.
[0011] Furthermore, the short section of the steel casing is provided with an internal thread, the long section is provided with an external thread, and the thread length is 15-30 mm.
[0012] Furthermore, the width of the head plate is 25 to 30 mm, and the thickness is 3 to 6 mm.
[0013] Furthermore, the length of the short straight pipe section of the steel casing is 50-80 mm, and the length of the long straight pipe section is the hole depth minus the short section length plus the overlapping length of the threaded connection of the two pipe sections. The overlapping length of the threaded connection can be taken as the pipe section thread length minus 5 mm.
[0014] Furthermore, the number of groove snaps on the head plates at both ends of the steel casing are 4.
[0015] The beneficial effects of the present invention are as follows:
[0016] The reinforced concrete beam post-hole strengthening method of the present invention uses structural adhesive to bond the steel casing to the inner wall of the concrete hole as a whole, thereby using the high-strength performance of the steel casing itself to compensate for the weakening of the bearing performance caused by the concrete hole opening; at the same time, the casing is divided into long and short segments and the short segment internal thread wraps the long segment external thread, thereby avoiding the situation that the front end structural adhesive may be incomplete due to the friction of the hole wall during the insertion of the long segment casing into the hole, and ensuring that the outer surface of the casing and the inner wall of the hole are filled with structural adhesive. At the same time, through the threaded tightening connection of the long and short casings and the setting of the head plate, the concrete on both sides of the hole is locally compressed, and a small amount of overflowed structural adhesive is also filled between the head plate and the concrete surface. These measures are helpful to eliminate the local damage to the hole wall concrete caused by the post-hole opening, and play a comprehensive strengthening role on the hole. BRIEF DESCRIPTION OF THE DRAWINGS
[0017] Figure 1This is the elevation view of the reinforced concrete beam with the opening strengthened after opening;
[0018] Figure 2 It is the AA section view;
[0019] Figure 3 is a three-dimensional schematic diagram of a steel casing;
[0020] Figure 4 Schematic diagram of the connection between the long section and the short section of the steel casing.
[0021] In the figure, 1-concrete beam, 2-floor slab, 3-opening, 4-reinforced steel casing, 5-structural adhesive, 41-reinforced steel casing long section, 42-reinforced steel casing short section, 43-head plate, 44-groove snap-on. DETAILED DESCRIPTION
[0022] The present invention will be described in detail below based on the accompanying drawings and preferred embodiments, and the purpose and effects of the present invention will become more clear. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.
[0023] like Figure 1-4 As shown, a method for strengthening a reinforced concrete beam by rear opening is provided, and the method specifically comprises the following steps:
[0024] S1: Drill a round hole for the pipeline to pass through the beam as required, clean the hole and paint the surface layer on the side of the beam;
[0025] S2: Determine the size of the steel casing for reinforcement according to the beam width and the hole diameter, wherein the outer diameter of the steel casing is the hole diameter minus 4-6mm, and the wall thickness is determined based on the principle of equal strength of the beam cross section before and after the hole opening combined with the commonly used specifications of the steel casing; the steel casing is divided into two long and short sections along the hole opening direction, and both sections are provided with a head plate at the outer ends, and a plurality of grooves and bayonet holes are provided on the head plate for rotating the steel casing; the long section and the short section of the steel casing are connected to each other by setting internal and external threads at the junction, the long section of the steel casing adopts external threads, and the short section of the steel casing adopts internal threads;
[0026] S3: Before installing the steel casing, the structural adhesive is brushed on the side wall of the opening, and the structural adhesive is also brushed on the surface of the long section and the short section of the steel casing. The thickness of the structural adhesive is based on filling the gap between the outer wall of the steel casing and the hole wall; the structural adhesive has a bearing capacity higher than the strength of concrete and a slow setting function;
[0027] S4: First, extend the long section of the steel casing coated with structural adhesive into the hole until the head plate presses against the concrete surface on the beam side. Then, on the other side of the hole, extend the short section of the steel casing coated with structural adhesive into the hole. Then, use the groove of the head plate to tighten the connection, and finally ensure that the head plates at both ends of the casing are close to the concrete surface on the beam side.
[0028] S5: Avoid disturbance before the structural adhesive solidifies and hardens. After hardening, the hole reinforcement is completed.
[0029] The long section of the steel casing is provided with an external thread, and the short section is provided with an internal thread, and the thread length is 15-30mm. The width of the head plate is 25-30mm, and the thickness is 3-6mm. Before installing the steel casing, it is necessary to first apply structural adhesive to the side wall of the opening to ensure that the tiny pits that may exist on the inner wall of the concrete of the opening are filled with structural adhesive; in the process of putting the casing with structural adhesive on the surface into the hole, the longer the length of the casing extended into the hole, the greater the possibility of contact and friction between the front end of the casing and the hole wall. In this way, the structural adhesive at the front end of the casing may be partially scraped backwards, resulting in incomplete filling of the structural adhesive between the front end pipe wall and the hole wall. The present invention divides the casing into long and short sections, first puts the long section and then the short section, and combines the long and short sections with threaded connection, and the short section internal thread wraps the long section external thread, so as to ensure that the structural adhesive between the casing wall and the hole wall is fully filled after the casing is installed. At the same time, through the threaded tightening connection of the long and short sleeves and the setting of the head plate, the concrete on both sides of the hole is locally compressed, and a small amount of overflowed structural adhesive is also filled between the head plate and the concrete surface. These measures are helpful to eliminate the local damage to the hole wall concrete caused by the subsequent opening of the hole, and play a comprehensive strengthening role on the hole.
[0030] In order to achieve the above purpose, the straight pipe length of the short section of the steel casing is set to 50-80mm, and the straight pipe length of the long section is the hole depth minus the short section length plus the overlap length of the threaded connection of the two sections, and the overlap length of the threaded connection is taken as the section thread length minus 5mm. In order to tighten the long section and the short section, the groove bayonet of the head plate at both ends of the steel casing is 4.
[0031] Those skilled in the art can understand that the above are only preferred examples of the invention and are not intended to limit the invention. Although the invention is described in detail with reference to the above examples, those skilled in the art can still modify the technical solutions recorded in the above examples or replace some of the technical features therein with equivalents. Any modification, equivalent replacement, etc. made within the spirit and principle of the invention shall be included in the protection scope of the invention.
Claims
1. A method for strengthening a reinforced concrete beam by rear opening, characterized in that: The method specifically comprises the following steps: S1: Drill a round hole for the pipeline to pass through the beam as required, clean the hole and paint the surface layer on the side of the beam; S2: Determine the size of the reinforced steel casing according to the beam width and the hole diameter, wherein the outer diameter of the steel casing is the hole diameter minus 4-6mm, and the wall thickness is determined based on the principle of equal strength of the beam cross section before and after the hole opening combined with the commonly used specifications of the steel casing; the steel casing is divided into two long and short sections along the hole opening direction, and both sections are provided with a head plate at the outer ends, and a plurality of grooves and bayonet holes are provided on the head plate for rotating the steel casing; the long section and the short section of the steel casing are connected to each other by setting internal and external threads, the long section of the steel casing adopts external threads, and the short section of the steel casing adopts internal threads; S3: Before installing the steel casing, the structural adhesive is brushed on the side wall of the opening, and the structural adhesive is also brushed on the outer surface of the long and short sections of the steel casing. The thickness of the structural adhesive is based on filling the gap between the outer wall of the steel casing and the hole wall; the structural adhesive has a bearing capacity higher than the strength of concrete and a slow setting function; S4: First, extend the long section of the steel casing coated with structural adhesive into the hole until the head plate presses the concrete surface of the beam side, and then extend the short section of the steel casing coated with structural adhesive into the hole on the other side of the hole, and then tighten the connection using the groove of the head plate, and finally ensure that the head plates at both ends of the casing are close to the concrete surface of the beam side; S5: Avoid disturbance before the structural adhesive solidifies and hardens. After hardening, the hole reinforcement is completed; The short section of the steel casing is provided with an internal thread, the long section is provided with an external thread, and the thread length is 15-30 mm; The length of the short straight pipe section of the steel casing is 50-80 mm, and the length of the long straight pipe section is the hole depth minus the short section length plus the overlap length of the threaded connection of the two pipe sections. The overlap length of the threaded connection is taken as the pipe section thread length minus 5 mm.
2. The reinforced concrete beam rear hole strengthening method according to claim 1, characterized in that: The width of the head plate is 25-30 mm, and the thickness is 3-6 mm.
3. The method for strengthening reinforced concrete beams by rear opening according to claim 1, characterized in that: The number of groove snap-fits of the head plates at both ends of the steel casing are 4.