A prestressed reinforcement structure for concrete beam-column joints

Abstract

This utility model relates to a prestressed reinforcement structure for concrete beam-column joints, comprising a split steel sleeve consisting of multiple arc-shaped steel plates temporarily fixed to the outside of the frame column by high-strength bolts, with butt joints welded together to form a closed ring structure; a lower connecting steel plate horizontally welded to the bottom of the sleeve; an upper connecting steel plate covering the top of the beam and welded to the sleeve; chemical anchor bolts penetrating the lower connecting steel plate and anchored to the side wall of the prestressed concrete beam; additional longitudinal reinforcement including: steel bars within the beam width fully welded to the steel plate through Φ25mm plug weld holes; longitudinal reinforcement extending to the floor slab outside the beam width and anchored thereto, tied to the stirrups to form a grid; and a grouting layer filling the space between the column and the sleeve. This utility model avoids cutting off the beam, fully preserving the performance of the prestressed tendons; the sleeve and anchor bolts work together to improve the joint's load-bearing capacity and seismic resistance; the modular design adapts to different beam and column sizes, offering strong versatility; construction requires no large equipment, reducing interruptions to building functions.

Description

Technical Field

[0001] This utility model relates to the field of building structure reinforcement technology, and in particular to a prestressed reinforcement structure for concrete beam and column joints. Background Technology

[0002] In the field of building engineering, prestressed concrete structures are constructed by artificially applying prestress to the components before they bear external loads. This utilizes the excellent compressive properties of concrete to compensate for its insufficient tensile strength, effectively delaying cracking in the tension zone and thus significantly improving the crack resistance and stiffness of the structure.

[0003] With socio-economic development and changing building functional requirements, the number of existing building renovation and reinforcement projects is increasing. In the reinforcement of frame columns, the traditional method of increasing the cross-section usually requires cutting off the frame beam connected to the column for construction. However, when the connecting beam is a prestressed concrete beam, cutting off the beam will cause the prestressing tendons to fail, resulting in the destruction of the original prestressing system and a significant reduction in load-bearing capacity. This makes it difficult to meet the requirements of modern building functional upgrades and load increases, exposing the obvious limitations of traditional reinforcement methods in the treatment of prestressed concrete beam-column joints.

[0004] Currently, there is a technological gap in reinforcement techniques for special working conditions of prestressed concrete beam-column joints, namely, in ensuring the integrity of the prestressed system and the structural safety. Utility Model Content

[0005] The technical problem to be solved by this utility model is to provide a prestressed reinforcement structure for concrete beam and column joints, which wraps the joint area with steel sleeve components and connects the original structure with chemical anchors to achieve effective load transfer.

[0006] The technical solution adopted by this utility model to solve its technical problem is: a prestressed reinforcement structure for concrete beam-column joints, comprising:

[0007] The split steel sleeve consists of multiple arc-shaped steel plates temporarily fixed to the outside of the frame column by high-strength bolts, and the joint is connected into a ring by bevel welds;

[0008] The lower connecting steel plate is horizontally welded and fixed to the bottom of the steel sleeve, parallel to the bottom surface of the prestressed concrete beam;

[0009] The upper connecting steel plate covers the top surface of the prestressed concrete beam, and its two ends are welded to the top bevel of the steel sleeve.

[0010] Chemical anchor bolt assembly, penetrating the lower connecting steel plate and anchoring to the side wall of the prestressed concrete beam;

[0011] The newly added longitudinal reinforcement includes: longitudinal reinforcement within the beam width, which is fully welded through the plug weld holes of the lower connecting steel plate; and longitudinal reinforcement outside the beam width, which extends upward and is anchored to the area to be removed from the floor slab.

[0012] A grouting layer is applied between the frame column and the steel sleeve.

[0013] Furthermore, the thickness of the arc-shaped steel plate of the split steel sleeve described in this utility model is ≥20mm, and the height of the butt joint weld is ≥8mm.

[0014] Furthermore, the thickness of both the lower connecting steel plate and the upper connecting steel plate of this utility model is 20mm, and the elevation error of the top surface of the upper connecting steel plate is ≤2mm.

[0015] Furthermore, the chemical anchor assembly of this utility model includes an M16 high-strength chemical anchor, the borehole diameter of which is 2mm larger than the anchor diameter, the anchoring depth is ≥150mm, and the distance from the center of the anchor hole to the prestressed duct inside the beam is ≥3 times the anchor diameter.

[0016] Furthermore, the anchorage length of the newly added longitudinal reinforcement in the floor slab removal area is ≥Lae, and it is tied with the stirrups to form a grid; the plug weld hole diameter is 25mm, the spacing is ≤200mm, the newly added longitudinal reinforcement is HRB400 steel bar with a diameter ≥20mm, and the thickness of the plug weld with the steel plate is ≥8mm.

[0017] The beneficial effect of this utility model is that it solves the defects existing in the background technology.

[0018] 1. Better preservation of structural performance: For prestressed concrete beams connected to frame columns, there is no need to cut the beams, avoiding the failure of prestressing tendons, and fully preserving the prestressing performance of the beams, ensuring the rationality and safety of the entire structure's stress distribution, which greatly improves the reliability of the structure compared to traditional reinforcement methods.

[0019] 2. The steel sleeve tightly wraps the prestressed concrete beam, and together with the chemical anchors, the reinforcement device forms an integral whole with the original structure. This effectively transfers and distributes the load, improves the bearing capacity and seismic performance of the column-beam joint, and enhances the overall stability of the building structure.

[0020] 3. The modular design adapts to different beam and column sizes; the design of the steel sleeve and the arrangement of the chemical anchors can be flexibly adjusted, making it highly versatile and practical.

[0021] 4. No large equipment is required for construction, reducing interruptions to building functions and making the construction process simple and quick. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the reinforcement structure of this utility model;

[0023] Figure 2 This is a schematic diagram of the steel sleeve structure of this utility model;

[0024] Figure 3 This is a schematic diagram of the connection structure between the steel sleeve and the upper steel plate of this utility model;

[0025] In the diagram: 1-Steel hoop, 11-Arc-shaped steel plate one, 12-Arc-shaped steel plate two, 13-Upper connecting steel plate, 2-Hole one (through-hole plug-welded hole), 3-Hole two (chemical anchor bolt hole), 4-Chemical anchor bolt, 5-Outer longitudinal reinforcement within beam width, 6-Longitudinal reinforcement within beam width, 7-Floor slab, 8-Frame column, 9-Prestressed concrete beam, 10-Stirrup. Detailed Implementation

[0026] The present invention will now be described in further detail with reference to the accompanying drawings and preferred embodiments. These drawings are simplified schematic diagrams, illustrating only the basic structure of the present invention, and therefore only show the components relevant to the present invention.

[0027] like Figures 1-3 The prestressed concrete beam-column joint reinforcement structure shown includes:

[0028] The split steel sleeve 1 is temporarily fixed to the outside of the frame column 8 by multiple arc-shaped steel plates (arc-shaped steel plate 11 and arc-shaped steel plate 22) with high-strength bolts, and the joint is connected into a ring by bevel weld.

[0029] The lower connecting steel plate is horizontally welded and fixed to the bottom of the steel sleeve, parallel to the bottom surface of the prestressed concrete beam 9;

[0030] The upper connecting steel plate 13 covers the top surface of the prestressed concrete beam, and its two ends are welded to the top of the steel sleeve through the hole 2 bevel.

[0031] The chemical anchor bolt 4-component is anchored to the prestressed concrete beam sidewall through hole 2-3, penetrating the lower connecting steel plate;

[0032] The newly added longitudinal reinforcement includes: longitudinal reinforcement 6 within the beam width range, which is fully welded through the plug weld hole of the lower connecting steel plate; and longitudinal reinforcement 5 outside the beam width range, which extends upward and is anchored to the chiseled area of ​​the floor slab 7; the newly added longitudinal reinforcement has stirrups 10 on the outside.

[0033] A grouting layer is applied between the frame column and the steel sleeve.

[0034] The reinforcement method steps are as follows:

[0035] 1. Erecting scaffolding: A full-span scaffolding will be erected around the frame columns to be reinforced and the connected prestressed concrete beams. The spacing between scaffold uprights and the step distance of horizontal bars will be determined according to the construction plan. Scaffold boards will be fully laid and secured, and guardrails and safety nets will be installed around the perimeter to form a safe working platform. A level will be used to measure and position the scaffolding, ensuring that the elevation meets the operational space requirements for chiseling and installation, with an error controlled within ±5mm.

[0036] 2. Removal of the floor slab surrounding the prestressed beam: Using a hydraulic breaker in conjunction with manual chiseling, remove the concrete from the floor slab within a 100mm radius on both sides of the prestressed beam, down to the surface of the bottom reinforcing steel bars, while preserving the reinforcing steel bars within the slab. Use a rebar detector to locate the reinforcing steel bars within the slab to avoid damage during the chiseling process. After chiseling, clean up the debris, remove rust from the exposed reinforcing steel bars at the edges of the slab, and apply epoxy anti-corrosion coating.

[0037] 3. Remove concrete around the frame column: Along the entire height of the frame column, remove loose concrete and protective layer from the column surface, with a removal thickness of 30-50mm (determined according to the design reinforcement dimensions), exposing the solid base layer. When using a pneumatic hammer, leave a 10mm manual trimming layer from the surface of the longitudinal reinforcement and stirrups inside the column to avoid mechanical vibration damaging the original reinforcement. After removal, roughen the column surface to form a rough surface with a depth ≥6mm and a spacing ≤100mm, and clean away dust and debris.

[0038] 4. Install the lower steel sleeve assembly: The steel sleeve is made of hot-rolled steel plate (the specific steel type depends on the design drawings). The lower sleeve includes the column body ring sleeve and the beam bottom connecting steel plate. First, put the ring sleeve (20mm thick, in two pieces) on the outside of the frame column and temporarily fix it with bolts. Adjust the verticality of the sleeve to ensure that the deviation between its center and the column center is ≤3mm.

[0039] 5. Welded connection between sleeves: The joint of the sleeves is welded with a bevel, and the weld height is ≥8mm. Before welding, remove oil and rust from the joint surface, use symmetrical welding method to reduce welding deformation, and perform weld flaw detection after welding to ensure effective force transmission between the sleeve and the bottom of the beam.

[0040] 6. Connection between the hoop and the prestressed beam chemical anchor: Drill holes at the corresponding positions on the connecting steel plate on the side of the beam (hole diameter 2mm larger than the anchor diameter), using M16 high-strength chemical anchors (anchoring depth 150mm, the type of chemical anchor depends on the design drawings), and tighten using an electric torque wrench to ensure the anchor tension design value ≥60kN. Avoid drilling the prestressing tendons inside the beam, and locate the prestressing ducts using a radar detector, ensuring the drilling spacing is ≥3d (d is the anchor diameter).

[0041] 7. Install the upper connecting steel plate: Install a steel plate (20mm thick) on the top surface of the prestressed beam. The two ends of the steel plate are welded to the lower steel sleeve using bevel welding, with a weld height ≥10mm, forming a continuous steel sleeve support system. During welding, a rigid fixing method is used to control deformation and ensure that the top surface of the steel plate is at a consistent elevation (error ≤2mm).

[0042] 8. Tying reinforcing bars:

[0043] 1) Longitudinal reinforcement within the beam width: The through-hole plug welding process is adopted. Φ25mm plug welding holes (spacing ≤200mm) are opened in the steel plate under the steel sleeve. The newly added longitudinal reinforcement (HRB400, diameter 20mm, depending on the design drawings) is passed through the plug welding holes and fully welded to the bottom surface of the steel plate. The weld thickness is ≥8mm.

[0044] 2) Longitudinal reinforcement outside the beam width: The longitudinal reinforcement extends upward and passes through the area of ​​the removed floor slab. The anchorage length is ≥ Lae. The upper longitudinal reinforcement of the remaining prestressed beam is connected to the upper steel plate by through-hole plug welding and is fully welded to the top surface of the upper steel plate. The weld thickness is ≥ 8mm.

[0045] 3) Perform tasks such as tying stirrups according to the design drawings.

[0046] 9. Formwork Erection and Grouting: Formwork is used to enclose the column body for pouring high-strength, non-shrink grout (compressive strength ≥ 60 MPa). Sealing strips are applied to the formwork joints to prevent grout leakage. The column surface is moistened with water 24 hours before grouting. Pressure grouting is used to inject grout from the bottom injection holes of the formwork until grout overflows from the top outlet holes. After compaction, the outlet holes are sealed.

[0047] 10. Maintenance and Finished Product Protection:

[0048] 1) After grouting is completed, cover with plastic film for moisture retention and curing. When the ambient temperature is ≥15℃, the curing time should be ≥7 days, during which time water should be sprinkled 3-4 times a day. Vibration of scaffolding and impact of construction loads are prohibited during the curing period. After the strength of the grout reaches 80% of the design value (tested by test blocks under the same conditions), the formwork and scaffolding should be removed.

[0049] 2) Apply concrete interface treatment agent to the outside of the steel sleeve, one coat each in the longitudinal and transverse directions, to enhance the adhesion between the mortar and the steel. The mortar should be polymer cement mortar with a thickness of 20-30mm (depending on the design drawings).

[0050] The above description is only a specific embodiment of the present utility model. Various examples and illustrations do not constitute a limitation on the substantive content of the present utility model. Those skilled in the art can make modifications or variations to the above-described specific embodiments after reading the description without departing from the essence and scope of the utility model.

Claims

1. A prestressed reinforcement structure for concrete beam-column joints, characterized in that: include, The split steel sleeve consists of multiple arc-shaped steel plates temporarily fixed to the outside of the frame column by high-strength bolts, and the joint is connected into a ring by bevel welds; The lower connecting steel plate is horizontally welded and fixed to the bottom of the steel sleeve, parallel to the bottom surface of the prestressed concrete beam; The upper connecting steel plate covers the top surface of the prestressed concrete beam, and its two ends are welded to the top bevel of the steel sleeve. Chemical anchor bolt assembly, penetrating the lower connecting steel plate and anchoring to the side wall of the prestressed concrete beam; The newly added longitudinal reinforcement includes: longitudinal reinforcement within the beam width, which is fully welded through the plug weld holes of the lower connecting steel plate; and longitudinal reinforcement outside the beam width, which extends upward and is anchored to the floor slab removal area. A grouting layer is applied between the frame column and the steel sleeve.

2. The prestressed reinforcement structure for concrete beam-column joints as described in claim 1, characterized in that: The thickness of the arc-shaped steel plate of the split steel sleeve is ≥20mm, and the height of the butt joint weld is ≥8mm.

3. A prestressed reinforcement structure for concrete beam-column joints as described in claim 1, characterized in that: The thickness of both the lower and upper connecting steel plates is 20mm, and the elevation error of the top surface of the upper connecting steel plate is ≤2mm.

4. A prestressed reinforcement structure for concrete beam-column joints as described in claim 1, characterized in that: The chemical anchor assembly includes an M16 high-strength chemical anchor with a drilled hole diameter 2 mm larger than the anchor diameter, an anchoring depth ≥ 150 mm, and a distance from the center of the anchor hole to the prestressed duct inside the beam ≥ 3 times the anchor diameter.

5. A prestressed reinforcement structure for concrete beam-column joints as described in claim 1, characterized in that: The newly added longitudinal reinforcement has an anchorage length of ≥Lae in the floor slab removal area and is tied with the stirrups to form a grid; the plug weld hole diameter is 25mm, the spacing is ≤200mm, the newly added longitudinal reinforcement is HRB400 steel bar with a diameter ≥20mm, and the plug weld thickness with the steel plate is ≥8mm.

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