Local compression-resistant protection device for existing beam jacking stress
By installing steel plates on the sides and bottom of existing beams and a structural grouting area, and using chemical bolts and grouting adhesive for connection, the problems of local stress concentration and uneven load transfer during the jacking process were solved, thereby improving the construction safety and load-bearing capacity of existing buildings.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-26
- Publication Date
- 2026-03-06
AI Technical Summary
In the construction of existing buildings, the addition of floors and the "stealing beams and replacing columns" process can lead to problems such as local stress concentration, accumulation of structural damage, uneven load transfer and poor stability during the jacking process, resulting in high construction safety risks and difficulty in ensuring quality.
The design employs a combination of side steel plates, bottom steel plates, and a structural adhesive grouting area. By fixing with chemical bolts and connecting with adhesive grout, the overall force is evenly distributed, avoiding local breakage and slippage, and enhancing load-bearing capacity and stability.
This ensured uniform stress distribution on the existing beams during the jacking process, preventing localized concrete breakage and structural failure, improving construction safety and load-bearing capacity, and guaranteeing the smooth progress of the renovation project.
Smart Images
Figure CN223974913U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of improving the quality of existing buildings in urban renewal, specifically a local compressive protection device for the lifting force of existing beams. Background Technology
[0002] With the advancement of urbanization and the gradual disappearance of the demographic dividend, the growth potential of the construction industry's incremental market is shrinking, while the importance of the existing market is becoming increasingly prominent. Quality improvement projects such as the maintenance, renovation, and revitalization of existing buildings will become the main market for urban renewal.
[0003] Due to the need to improve the quality of existing buildings, their functional requirements may change during their life cycle, such as adding floors, expanding, or renovating to extend the space of existing buildings. In many cases, this necessitates adding floors and "replacing beams and columns" in the existing load-bearing structure. The entire process of adding floors and "replacing beams and columns" requires first lifting the existing load-bearing structure (such as existing beams), with the lifting supports temporarily bearing the original upper load. Once the upper load is transferred to the newly added load-bearing components through a reasonable force transfer control method, subsequent renovation work can proceed. However, if the lifting supports directly apply force to the existing beams during the lifting process, several problems arise. Firstly, existing structures often accumulate varying degrees of damage during long-term service, such as surface cracking, flexural deformation, concrete carbonation and spalling, and steel reinforcement corrosion. These damages are particularly pronounced in humid and corrosive environments, especially in coastal areas, frigid regions, and areas with severe industrial pollution. The concentrations of water vapor, salt, or other harmful substances in the air are often high, and physical effects such as wet-dry cycles, diurnal temperature variations, or freeze-thaw cycles are also more intense. Under the dual effects of chemical corrosion and physical erosion, existing structural damage is very likely to occur, and once it occurs, it will accumulate and expand rapidly. This will result in a thinner concrete cover, a smaller effective load-bearing area, and a decrease in material strength, ultimately leading to a significant decline in structural durability and load-bearing capacity. In particular, concrete in areas with relatively severe damage is more likely to be damaged during the jacking process. On the other hand, the existing structure has poor surface flatness, making it impossible for the jacking support to achieve a seamless and tight fit with the existing structure. At the same time, the force exerted by the jacking support on the existing load-bearing structure is often large and extremely unevenly distributed, especially near the jacking support point, where stress concentration is particularly significant. The peak stress level in this area is much higher than the overall average stress, and once it reaches the concrete strength limit, the structure in this area will suffer strength failure. This will not only cause concrete cracking, steel bar yielding, structural surface collapse and deformation, but will also lead to a sudden drop in jack pressure, roof collapse at the top of the support, and a series of safety problems such as support breakage and lateral instability. This not only seriously affects the construction progress and quality of the renovation project, but also greatly increases the construction safety risks. Furthermore, as the service life increases, the material properties will gradually degrade, such as the gradual decrease in the compressive strength and elastic modulus of concrete, the degradation of the mechanical properties of steel bars, the weakening of the bond between steel bars and concrete, as well as concrete creep and steel bar stress relaxation. These factors will accelerate the deterioration of the overall structural performance. In addition, the combined effect of damage accumulation and uneven jacking force will make the existing load-bearing structure prone to strength failure or deformation instability during the jacking process if effective local compressive protection measures are not taken.
[0004] Existing beams, as the main objects to be lifted in the construction of additional floors and "beam-for-column" projects, are usually protected by steel plates or steel pads for localized compressive strength. This involves adding steel plates or pads between the lifting support and the existing beam to increase the bearing area, distribute concentrated loads, and reduce stress concentration. While this method is simple to operate, it still has the following significant drawbacks: First, the load-bearing capacity is relatively low. Because the surface of the existing beam is not flat, it is difficult to achieve a complete fit between the steel plate or steel pad and the beam, often resulting in small gaps. In the initial stage of lifting, the lifting force will be mainly transmitted through the contact points, leading to excessive stress at these points. When the stress at the contact points exceeds the concrete's strength limit, the contact points will break, and the gaps will close, easily causing problems such as displacement of the steel plates or steel pads and support collapse. Second, the overall stability is poor. The steel plate or steel pad is only used to transfer lateral force to the existing beam through friction. Without effective connection measures such as mechanical anchoring or chemical bonding, the steel plate or steel pad may slip laterally at the contact position on the beam surface under dynamic jacking load, which may lead to accidents such as jack depressurization, support collapse, and lateral instability of the support.
[0005] With the increasing number of existing building quality improvement and renovation projects, the renovation of existing load-bearing structures, including adding floors and "replacing beams with columns," is becoming more and more common. As the main objects to be lifted during the renovation process, how to effectively protect the existing beams from localized compressive stress remains a technological gap. This protection measure should not only be easy to construct but also ensure the load-bearing capacity and overall stability of the existing beams during lifting. Overcoming this key technical bottleneck is of paramount importance for promoting the sound development of existing building quality improvement in urban renewal. Utility Model Content
[0006] The purpose of this utility model is to provide a local compressive protection device for existing beams subjected to jacking stress, which has the advantages of high load-bearing capacity, strong overall stability, safety and reliability, and easy implementation.
[0007] The objective of this utility model is achieved through the following technical solution:
[0008] A localized compressive protection device for existing beams subjected to jacking stress includes:
[0009] The existing beams extend to the left and right sides;
[0010] Two beam side steel plates are fixed to the front and rear sides of the existing beam, respectively;
[0011] The bottom steel plate is located on the bottom side of the existing beam and welded to the two side steel plates of the beam.
[0012] The lifting support is placed on the bottom side of the steel plate at the bottom of the beam.
[0013] The existing beam, the side steel plates, and the bottom steel plate form a structural adhesive injection zone. The existing beam is also coated with a first steel adhesive sealing strip to seal the periphery of the structural adhesive injection zone. Adhesive injection pipes are inserted at the bottom of the front and rear sides of the structural adhesive injection zone, and vent pipes are inserted at the top of the front and rear sides of the structural adhesive injection zone. One end of the adhesive injection pipe and the vent pipe are connected to the structural adhesive injection zone, and the other end of the adhesive injection pipe and the vent pipe pass through the first steel adhesive sealing strip and are connected to the outside atmosphere. Second steel adhesive is injected into the structural adhesive injection zone through the adhesive injection pipes.
[0014] Compared with the prior art, the advantages of this utility model are:
[0015] 1. By coordinating the steel plates on the sides of the beam, the steel plates at the bottom of the beam, and the grouting area of the structure, the existing beam is subjected to uniform stress during the jacking process, avoiding local concrete breakage and structural failure, reducing stress concentration, and improving load-bearing capacity and safety.
[0016] 2. By fixing the side steel plates of the beam to the existing beam with chemical bolts and filling the structural injection area with a second steel-filled adhesive, the side steel plates, bottom steel plates, and existing beam are integrated to prevent displacement or lateral slippage of the side and bottom steel plates during the jacking process. The support frame is welded to the bottom steel plate, which enables the jacking support to effectively transfer force during the jacking process, avoiding safety issues such as jack depressurization, support collapse, and lateral instability, thus improving the safety and reliability of the jacking process. Attached Figure Description
[0017] Figure 1 This is a schematic diagram of an embodiment of a local compressive protection device for lifting and stressing existing beams according to this utility model;
[0018] Figure 2 yes Figure 1 A cross-sectional schematic diagram.
[0019] Labeling explanation: 1 Existing beam, 2 Beam side steel plate, 3 Beam bottom steel plate, 4 Support frame, 5 First steel glue sealing strip, 6 Glue filling pipe, 7 Exhaust pipe, 8 Chemical bolt. Detailed Implementation
[0020] The present invention will now be described in detail with reference to the accompanying drawings and embodiments:
[0021] like Figure 1-2 The diagram shown is a schematic representation of an embodiment of a local compressive protection device for existing beams subjected to jacking stress provided by this utility model:
[0022] A localized compressive protection device for existing beams subjected to jacking stress includes:
[0023] Existing beam 1 extends to the left and right sides;
[0024] Two beam-side steel plates 2 are fixed to the front and rear sides of the existing beam 1, respectively;
[0025] The bottom steel plate 3 is located on the bottom side of the existing beam 1 and is welded to the two side steel plates 2 of the beam.
[0026] The lifting support is located on the bottom side of the steel plate 3 at the bottom of the beam.
[0027] The existing beam 1, the side steel plate 2, and the bottom steel plate 3 form a structural grouting area. The existing beam 1 is also coated with a first steel grout sealing strip 5 for sealing the periphery of the structural grouting area. A grouting pipe 6 is inserted at the bottom of the front and rear sides of the structural grouting area, and an exhaust pipe 7 is inserted at the top of the front and rear sides of the structural grouting area. One end of the grouting pipe 6 and the exhaust pipe 7 are connected to the structural grouting area, and the other end of the grouting pipe 6 and the exhaust pipe 7 pass through the first steel grout sealing strip 5 and are connected to the outside atmosphere. A second steel grout is injected into the structural grouting area through the grouting pipe 6.
[0028] Furthermore, based on stress calculations, the side steel plates 2 and bottom steel plates 3 should be selected with appropriate strength and thickness to ensure that under the jacking load, the side steel plates 2 and bottom steel plates 3 do not undergo significant deformation, and can evenly transfer the jacking load to the existing beam 1. In addition, the width of the side steel plates 2 and bottom steel plates 3 in the front-to-back direction should be greater than the width of the support frame 4 in the front-to-back direction to form an effective load diffusion zone. The surface of the bottom steel plate 3 should be flat to ensure uniform stress distribution.
[0029] Furthermore, the butt weld between the beam side steel plate 2 and the beam bottom steel plate 3 is a single V-groove weld. Based on the stress calculation and structural requirements, the electrode type, groove angle, groove depth, and weld quality grade are determined to ensure a firm connection between the beam side steel plate 2 and the beam bottom steel plate 3.
[0030] Preferably, a total of 8 chemical bolts 8 are provided, with 4 bolts on each of the front and rear sides of the existing beam 1, so as to meet the bearing capacity requirements under the self-weight of the beam side steel plate 2.
[0031] Furthermore, based on stress calculations and structural requirements, the performance grade, nominal diameter, insertion length, hole spacing, and end distance of the chemical bolt 8 are determined.
[0032] The beam side steel plate 2 has a number of mounting holes arranged in a rectangular array, and each mounting hole is provided with a chemical bolt 8 for fixing to the existing beam 1.
[0033] The lifting support includes a jack and a support frame 4. The jack is installed on the installation ground below the existing beam 1, and the support frame 4 is mounted on the lifting part of the jack. The upper end of the support frame 4 is welded and fixed to the bottom side of the bottom steel plate 3 of the beam.
[0034] Preferably, the support frame 4 can be made of H-beams, box-beams, or lattice sections according to the stress calculation and structural requirements, and should meet the requirements of bearing capacity and overall stability under the action of jacking force; the support frame 4 and the bottom steel plate 3 of the beam are welded together with full circumference welds. According to the stress calculation and structural requirements, the type of welding rod, the size of the weld leg, and the quality grade of the weld are determined to ensure that the support frame 4 and the bottom steel plate 3 are firmly connected and can effectively and evenly transfer the jacking load upward;
[0035] The glue-filling pipe 6 and the exhaust pipe 7, located on the same side of the structural glue-filling area, are arranged diagonally.
[0036] The exhaust pipe 7 is angled so that when the second steel-filled adhesive overflows, it can flow back immediately, ensuring that the adhesive fully fills the structural adhesive filling area. The adhesive filling pipe 6 is horizontally arranged.
[0037] Furthermore, the inner diameter of the exhaust pipe 7 is the same as the inner diameter of the glue-filling pipe 6.
[0038] The installation steps and usage methods of this utility model are roughly as follows:
[0039] S1. Remove the surface layer, plaster layer, damaged concrete and loose debris from the bottom and sides of the existing beam 1 to ensure that the beam surface is smooth and free of any debris; drill holes on both sides of the existing beam 1 with an electric drill, and use a cutting machine to open installation holes on the beam side steel plate 2. Install the beam side steel plate 2, ensuring that the installation holes of the beam side steel plate 2 are aligned with the holes in the existing beam 1. Insert chemical tubes into the holes, and then use an electric drill to install chemical bolts 8 to fix the beam side steel plate 2 to the existing beam 1.
[0040] S2. Use temporary support components to fix the bottom steel plate 3 of the beam. Use a level to measure in two vertical directions of the bottom steel plate 3 of the beam to accurately control the level of the bottom steel plate 3 of the beam. Then, weld the bottom steel plate 3 of the beam to the side steel plate 2 of the beam. After the weld strength meets the design requirements, remove the temporary support components.
[0041] S3. Using a grooving device, grooves are cut into the existing beam 1 at the preset positions of the glue-filling pipe 6 and the exhaust pipe 7. The glue-filling pipe 6 and the exhaust pipe 7 are embedded in the grooves. The first steel glue is evenly applied to the edge of the structural glue-filling area using a scraper to form a continuous closed first steel glue sealing strip 5.
[0042] S4. Connect the grouting machine to the grouting pipe 6 and continuously inject the second steel grout into the structural grouting area using the pressure grouting process. Stop grouting only after the vent pipe 7 continuously overflows with the same type and amount of steel grout as the injected grout, so as to ensure that the grout fully fills the structural grouting area.
[0043] S4. Install jacks on the installation ground below the existing beam 1, and splice the support frame 4 in sections from bottom to top until the support frame 4 is close to the bottom of the beam bottom steel plate 3. Start the jacks located at the bottom of the support frame 4 and apply a small lifting force to tighten the support frame 4 and the beam bottom steel plate 3. Finally, connect the support frame 4 and the beam bottom steel plate 3 with a full circumferential fillet weld.
[0044] S5. After the strength of the second steel glue inside the glue-filling area of the structure reaches the design value, the subsequent formal jacking and modification project will be carried out.
[0045] The above description is only a preferred embodiment of the present utility model, but the protection scope of the present utility model is not limited thereto. Any equivalent substitutions or changes made by those skilled in the art within the technical scope disclosed in the present utility model, based on the technical solution and the inventive concept of the present utility model, should be included within the protection scope of the present utility model.
Claims
1. A partial compression protection device for use in the jacking of existing beams, characterised in that, The utility model relates to a kind of structure of pouring glue for existing beam, including: Existing beam (1), extends to left and right sides; Two beam side steel sheets (2) are fixed to the front and rear sides of existing beam (1) respectively; Beam bottom steel sheet (3) is arranged at the bottom side of existing beam (1), and is welded with two beam side steel sheets (2); Jack-up support is supported at the bottom side of beam bottom steel sheet (3); Wherein, the structure pouring glue area is formed between the existing beam (1), beam side steel sheet (2) and beam bottom steel sheet (3), and the first pouring steel glue sealing band (5) for sealing the periphery of structure pouring glue area is coated on the existing beam (1);The bottom of the front and rear sides of structure pouring glue area is inserted with pouring glue pipe (6), and the top of the front and rear sides of structure pouring glue area is inserted with exhaust pipe (7), one end of pouring glue pipe (6) and exhaust pipe (7) is communicated with structure pouring glue area, the other end of pouring glue pipe (6) and exhaust pipe (7) is all through first pouring steel glue sealing band (5) and is communicated with external atmosphere;Second pouring steel glue is injected in structure pouring glue area through pouring glue pipe (6).
2. The partial compression protection device for the jacking of existing beams (1) according to claim 1, characterized in that: The mounting hole in the form of rectangular array is opened in beam side steel sheet (2), and chemical bolt (8) fixed with existing beam (1) is arranged in each mounting hole.
3. The partial compression protection device for the jacking of existing beams (1) according to claim 1, characterized in that: The jack-up support includes jack and support frame (4), the jack is installed on the installation ground below existing beam (1), the support frame (4) is erected on the jacking part of jack, and the upper end of support frame (4) is welded and fixed with the bottom side of beam bottom steel sheet (3).
4. The partial compression protection device for the jacking of existing beams (1) according to claim 1, characterized in that: Pouring glue pipe (6) and exhaust pipe (7) are diagonally arranged in the same side of structure pouring glue area.
5. Partial compression protection device for the jacking of forces of existing beams (1) according to claim 4, characterized in that: The exhaust pipe (7) is obliquely arranged, and the pouring glue pipe (6) is horizontally arranged.