Method for reinforcing existing brick-concrete structure house without home entry through cooperation of prestress lifting and cable pulling

Abstract

The invention discloses a method for reinforcing an existing brick-concrete structure house without entering a house through cooperation of prestress lifting and cable pulling. The method comprises the following steps that (1) early-stage detection (including actual measurement of plane layout and wall perpendicularity, similarly hereinafter) and scheme design are conducted; (2) mounting a lifting system; (3) cable-stayed system construction; (4) carrying out cooperative stress on prestress lifting and cable pulling; and (5) monitoring and acceptance. The method has the remarkable advantages that home-entry construction is not needed, resident relocation and placement are not needed, indoor decoration is not damaged, agreements are easy to achieve, and the indoor area is not occupied; reinforcement efficiency is high, external construction is standardized, and the construction period is shortened by about 50% compared with traditional reinforcement; thirdly, a stress system is flexible, local or overall structures can be reinforced in a targeted manner, and different structures can be adapted; and fourthly, the cost is low, the direct cost is only about 50% of that of home-entry reinforcement, and the cost of relocation, placement and the like and a large amount of coordination time are saved.

Description

Technical Field

[0001] This invention relates to the field of building structure reinforcement technology, and in particular to a method for reinforcing existing brick-concrete structure houses without entering the house using a combination of prestressed support and cable tensioning. Background Technology

[0002] Brick-concrete structures rely primarily on brick walls for load-bearing, with concrete slabs or precast concrete slabs serving as horizontal structural members. Their seismic resistance, crack resistance, and durability are relatively weak. This is especially true for older brick-concrete buildings constructed between the 1970s and 1990s, particularly five-story or higher buildings with 24 load-bearing walls. These buildings typically have ring beams and structural columns, or none at all. The lower floors often suffer from insufficient compressive bearing capacity of the masonry, and are frequently identified as dangerous buildings after technical assessment, posing serious safety hazards and severely threatening the lives and property of residents. Therefore, improving their structural safety is urgently needed.

[0003] Traditional reinforcement methods require in-home installation, such as reinforcing interior walls with steel mesh and mortar. This necessitates the removal of the finishing layer and plaster layer, requiring relocation and resettlement of residents. This presents numerous problems, including high relocation and resettlement costs, difficulty in reaching agreements on decoration compensation, challenges in advancing the reinforcement project, long start-up periods, and compensation costs far exceeding the project cost. These issues not only incur huge expenses but also easily exacerbate conflicts.

[0004] To address the aforementioned issues, the "prestressed support and cable-stayed reinforcement method without entering the building" has emerged. This method enhances structural safety without requiring entry into the building. The construction process is primarily carried out externally, eliminating the need for residents to relocate or vacate their homes. This reduces indoor construction steps, saving on relocation and resettlement costs, renovation and restoration compensation, and other expenses. It maximizes the preservation of residents' normal lives, balancing safety, public welfare, and economic needs with minimal intervention, reducing social conflict, and improving the efficiency of renovation projects. This innovative approach is a significant advancement in the reinforcement industry. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a method for reinforcing existing brick-concrete structures with prestressed support and cable tension without entering the house, which solves many problems of traditional house reinforcement and effectively improves the structural safety of existing brick-concrete structures without disturbing the normal life of residents.

[0006] The technical problem to be solved by the present invention is achieved through the following technical solution:

[0007] A method for reinforcing existing brick-concrete structures without entering the building using a combination of prestressed support and cable tensioning includes the following steps:

[0008] (1) Preliminary inspection and scheme design: Inspect the current status of the building structure, measure the plan layout and wall verticality, determine the location of the support and cable tension points and the load distribution ratio; use structural calculation software to simulate the stress state, optimize the parameters of external support and cable tension, and form a "one building, one scheme";

[0009] (2) Installation of the support system: Anchor piles are constructed on the outside of the building and preloaded and sealed. Concrete support columns are poured and positions for hydraulic jacks are reserved. The ring beam under the extended load-bearing wall is extended above. Hydraulic jacks are installed in the gap between the extended ring beam and the outer support components to provide a source of prestress.

[0010] (3) Cable system construction: Using directional drilling technology, drill holes along the designed trajectory from the outdoor incident point to the anchorage section under the ring beam of the indoor load-bearing wall at the set angle, orientation and diameter; if necessary, use bottom hole enlargement technology to enlarge the diameter of the anchorage end to the target diameter; install anchor cables; inject anchoring material into the anchorage section; perform prestressing tensioning and anchor sealing; and fill the entire borehole with secondary grouting.

[0011] (4) Cooperative stress of prestressed support and cable tension: The external support structure is constructed from bottom to top. After each layer is constructed, the prestressed support of that layer is completed before constructing the layer above it. This process is repeated to complete the construction of the external support structure unit and its prestressed support. The prestressed cable tension is constructed from top to bottom. After the prestress of that layer is tensioned, locked, and the anchoring material is injected for the second time, the prestressed cable tension of the next layer is constructed. This process is repeated to complete the construction of the prestressed cable tension on the same external support structure unit. Each prestressed support and cable tension is precisely measured to ensure that the load distribution between the two reaches the design value.

[0012] (5) Monitoring and acceptance: Install displacement sensors and stress gauges to monitor the stress and strain of the structure in real time during the reinforcement process, and adjust the cable prestress value in an information-based manner to meet the requirements.

[0013] Preferably, in the above technical solution, the building structure in the preliminary testing and scheme design is a brick-concrete structure house that relies on brick walls for load-bearing and concrete floor slabs or precast slabs as horizontal components, which has relatively weak seismic performance, crack resistance and durability.

[0014] Preferably, in the above technical solution, in the preliminary testing and scheme design, the brick-concrete structure 24-wall load-bearing building with insufficient vertical component bearing capacity generally has a ring beam, and structural columns may or may not be present.

[0015] Preferably, in the above technical solution, during the installation of the lifting system, the pile foundation of the support structure adopts anchor static pressure piles, and the pile, pile cap parameters and load-bearing sealing parameters are designed according to the reaction force at the bottom of the support structure column and the geological conditions.

[0016] Preferably, in the above technical solution, during the installation of the lifting system, prestressed support components are set on the outside of the building's exterior wall or column base, and prestress is applied by hydraulic jacks to generate an upward lifting force in the support structure, directly sharing the load of the wall, beam, and slab.

[0017] Preferably, in the above technical solution, an inclined directional hole is dry-drilled inward at the incident point on the outside of the load-bearing wall according to the design parameters. If necessary, the hole is enlarged in the planned anchoring section. The hole is suspended downward to the bottom of the ring beam by steel cable. Prestress is applied by tensioning the anchor cable, and the equivalent lifting load generated by the cable tension is transferred to the external support structure.

[0018] Preferably, in the above technical solution, in the prestressed support and cable tensioning, the support system uses the prestress applied by the hydraulic jack to generate an upward support force on the supporting structure, directly sharing the load of the wall, beam, and slab; the cable tensioning system uses the prestress applied by the anchor cable tensioning to generate an upward component force, which, together with the support force, transfers the prestress to the vertical support members, reducing the original structural stress level.

[0019] Preferably, in the above technical solution, during the monitoring and acceptance process, the monitoring data from the displacement sensor and stress gauge are used to monitor the structural stress and strain in real time during the reinforcement process, and to adjust the cable prestress value in an information-based manner to meet the requirements.

[0020] Preferably, the above technical solution is applicable to old residential buildings with brick-concrete or bottom-frame structures where earthquake resistance or load-bearing capacity needs to be improved but residents have not been relocated; protective renovation scenarios where the original interior appearance needs to be preserved during the reinforcement of historical buildings; and scenarios where the reinforcement of street-facing buildings needs to avoid affecting commercial operations during construction.

[0021] The above-described technical solution of the present invention has the following beneficial effects:

[0022] 1. No need to enter the house for construction: No need to relocate or resettle residents, no damage to interior decoration, no need for compensation, and it is easy to reach an agreement with residents; it does not occupy the indoor usable area and is suitable for existing residential buildings, hospitals, schools and other buildings.

[0023] 2. High reinforcement efficiency: The external construction process is standardized, and the construction period is shortened by about 50% compared with traditional reinforcement, thus reducing the urban renewal cycle.

[0024] 3. Flexible load-bearing system: It can be used to reinforce local components (such as cantilever beams and old walls) or the entire structure, adapting to different structural forms.

[0025] 4. Significantly reduced costs: Compared with in-home reinforcement, the direct cost of non-in-home reinforcement is only about 50% of that; it also saves on resident relocation and resettlement costs, avoids damage to interior decoration and compensation and repair costs, and saves a lot of time and costs of "persuasion". Attached Figure Description

[0026] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments of the invention and, together with their description, serve to explain the principles of the invention.

[0027] Figure 1 A schematic diagram of prestressed support combined with prestressed suspension reinforcement for the gable wall;

[0028] Figure 2 This is a schematic diagram of prestressing tension and lifting force;

[0029] Figure 3 A schematic diagram of the cable-stayed bridge system construction;

[0030] Figure 4A This is a schematic diagram of step 1 in the construction of the shoulder beam;

[0031] Figure 4B This is a schematic diagram of step 2 in the construction of the shoulder beam;

[0032] Figure 4C This is a schematic diagram of step 3 in the construction of the shoulder beam;

[0033] Figure 4D This is a schematic diagram of step 4 in the construction of the shoulder beam;

[0034] Figure 5A This is one of the detailed flowcharts of an embodiment of this application.

[0035] Figure 5B This is the second detailed flowchart of an embodiment of this application.

[0036] Among them: 1-support column, 2-shoulder beam, 3-jack, 4-socket. Detailed Implementation

[0037] Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that, unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the invention.

[0038] Example 1

[0039] This example is a building with a total construction area of ​​2900m². 2 The building is a six-story brick-concrete residential structure. Structural testing revealed that the ratio of the wall resistance to the load effect on the first to third floors did not meet the required specifications, indicating insufficient compressive bearing capacity of the masonry. Reinforcement is necessary. The prestressed support and cable-stayed reinforcement method described in this invention, without requiring entry into the building, is applicable.

[0040] 1. Preliminary testing and solution design:

[0041] Structural condition inspection: A comprehensive inspection of the residence revealed that the load-bearing capacity of the walls on the first to third floors was insufficient.

[0042] Load calculation and simulation: The structural calculation software is used for simulation analysis. Specifically, the structural calculation software is used to establish a three-dimensional model of the building as a whole, and parameters such as load, material strength and floor height are input. The model is assembled into a whole calculation model through the floor assembly. Then, the load-effect ratio of the brick-concrete structure building is obtained through the whole calculation. Of course, this application is not limited to this. Those skilled in the art can also confirm the scheme based on engineering experience. For example, in the 1980s and 1990s, the 5-6 story brick-concrete structure buildings generally have insufficient load-bearing capacity in the walls of the 1st to 3rd floors. The general principles for selecting the scheme are: (1) At the ring beam of the 2nd to 6th floors, the outer side of the exterior wall (intersection of longitudinal and transverse walls) should be given priority to the support scheme. If the simple support scheme cannot solve the load-bearing capacity problem of the walls of the 1st to 3rd floors, the scheme of support + cable tension should be considered; (2) At the balcony, the partition wall is generally provided with a cantilever beam. The root of the cantilever beam can bear a large "support" force. Therefore, the transverse wall at the axis of the balcony partition wall can generally solve the problem of insufficient wall load-bearing capacity by using a simple support scheme.

[0043] Based on simulation results, this embodiment proposes a "lifting + cable pulling" collaborative reinforcement scheme:

[0044] A vertically upward prestress of 50kN is applied to the outer ring beam of the exterior wall of the 2nd to 4th floors to share the load of the wall of the 1st to 3rd floors;

[0045] A vertically upward prestress of 165kN is applied under the cantilever beams of balconies on floors 2 to 6 to reduce stress at the beam root.

[0046] At the outer floor level of the 3rd to 5th floors, a 70kN upward tension force at a 45° angle is applied through a cable system to distribute the pressure on the wall in conjunction with the lifting force.

[0047] 2. Lifting system installation:

[0048] Anchor pile construction: Anchor piles (pre-loaded sealing piles) are constructed on the outside of the building, with a pile length of 12m and a total of 52 piles; concrete support columns are poured, with reserved positions for hydraulic jacks, and the ring beam under the extended load-bearing wall is connected above.

[0049] Jack installation: Install digital display hydraulic jacks in the gap between the extended ring beam and the outer support column. Set up one jack at each lifting point to provide prestress.

[0050] 3. Cable system construction:

[0051] Directional drilling: Using directional drilling technology, a hole is drilled from an outdoor incident point to the indoor anchorage section located under the ring beam of the load-bearing wall, at a predetermined angle, azimuth, and diameter, following the designed trajectory. The hole diameter is 60mm. If necessary, bottom hole reaming technology is used to enlarge the hole diameter at the anchorage end to the target diameter.

[0052] Anchor cable installation: Install anchor cables using two high-strength, low-relaxation steel strands. The anchorage length should be at least 0.85 meters (the actual anchorage length and borehole diameter can be increased according to calculations), and the design tensile force should be 130 kN. Anchoring material should be poured into the anchorage section.

[0053] Prestressing tensioning and anchor sealing: The anchor cable is prestressed and then anchored after being tensioned to the design tension.

[0054] Filling the borehole: After the upper cable system is tensioned and locked, grout is injected into the borehole a second time until grout overflows from the borehole opening, ensuring that the steel strands are tightly bonded to the wall. The pre-tensioning method is adopted. The first grouting is used to form an anchoring section of 1 meter, then tensioning is performed at about 130KN, and the second grouting is performed until grout overflows from the borehole opening.

[0055] Construction of the lower layer cable system: After the upper layer cable system has completed the above steps, the lower layer prestressed cables are constructed sequentially from top to bottom according to the same process until all cable construction of the same external support structure unit is completed.

[0056] 4. Prestressed support and cable tension working together:

[0057] The external support structure is constructed from bottom to top. After each layer is constructed, the prestressing support for that layer is completed before constructing the layer above it. This principle is followed to complete the construction of each external support structure unit and the application of its prestressing support. For example, 50kN of vertical upward prestress is applied to the outer ring beam of the exterior wall on floors 2-4, and 165kN of vertical upward prestress is applied to the cantilever beam of the balcony on floors 2-6. The layer above is constructed only after the support for that layer is completed.

[0058] Construction proceeds layer by layer. After completing the construction of the supporting structure and prestressing support of the current floor, the supporting structure of the next floor is constructed in sequence. The process of "constructing the supporting structure → applying prestressing support" is repeated until the construction of the supporting structure units and the application of prestressing support of all floors are completed.

[0059] To achieve the "lifting" goal described in the construction method, the construction of the shoulder beams for each floor is carried out in the following four steps:

[0060] (1) Complete the prestressing application: Apply prestress between the shoulder beam 2 and the support column 1 (after the first concrete pour and the requirements are met) using miniature jacks 3 to ensure that the designed prestress value is reached, and complete the prestressing application operation of this stage (arrow indicates that the prestressing application is completed).

[0061] (2) Complete the second concrete pouring of the support column and reach the design strength: Perform the second concrete pouring of support column 1, and wait for its strength to reach the design requirements after the pouring is completed.

[0062] (3) Unload and remove the jacks to complete the prestressing conversion: After the concrete of the second pour of the support column 1 reaches the design strength, unload the jacks 3 and then remove them from the construction position.

[0063] (4) Grouting at the location where the jack is placed: High-strength micro-expansion grouting material is used to over-grout the gap where the jack 3 was originally placed to ensure the integrity and stability of the structure.

[0064] The prestressed cable tensioning is carried out from top to bottom. After the prestressing of this layer is tensioned, locked, and the anchoring material is injected for the second time, the prestressed cable tensioning of the next layer is constructed. This principle is followed to complete the prestressed cable tensioning construction on the same external support structure unit. For example, if a 70kN upward tension is applied through the cable tensioning system at the outer floor elevation of the 3rd to 5th floors of the exterior wall, after the tensioning, locking, and secondary grouting of this layer are completed, the next layer is constructed.

[0065] Each prestressed lift and cable tensioning operation involves precise load measurement to ensure that the load distribution reaches the design value.

[0066] 5. Monitoring and Acceptance:

[0067] Monitoring: Install displacement sensors and stress gauges to monitor the deformation of the reinforced structure in real time, and continue for 1 to 3 months to confirm stress stability.

[0068] Acceptance: The structural deformation and stress are within the allowable range, the reinforcement effect meets the design requirements, and the acceptance is qualified.

[0069] The method for reinforcing existing brick-concrete structures without intrusion using prestressed support and cable tensioning, as described in this application, has the following principle and synergistic mechanism:

[0070] 1. Lifting System: Prestressed support components are installed on the outside of the building's exterior walls or column bases. Prestress is applied by hydraulic jacks, which causes the support structure to generate an upward lifting force, directly sharing the load of the walls, beams, and slabs.

[0071] 2. Cable-stayed system: The target anchorage section is located at the bottom of the ring beam of the load-bearing wall outdoors. An inclined directional hole is drilled inward from the positioning incident point on the outside of the load-bearing wall. The cable is suspended downward to the bottom of the ring beam. Prestress is applied by tensioning the anchor cable, and the equivalent lifting load generated by the cable is transferred to the external support component.

[0072] 3. Synergistic effect: The jacking provides upward support force, and the cable tension provides upward component force. The two work together to transfer the applied prestress to the vertical support members, reduce the stress level of the original structure, and improve the load-bearing capacity and seismic performance of the original structure.

[0073] The key technical points of this application are:

[0074] 1. Lifting force control: The lifting force is precisely controlled by a digital display hydraulic jack to avoid local overload of the structure.

[0075] 2. Cable system design: The cable anchor points need to be embedded in the ring beam and the solid masonry below it. Through the incident point at the end of the outdoor load-bearing wall, a hole is drilled along the preset trajectory and predetermined diameter to the anchor section set at the bottom of the ring beam. If necessary, the hole in the anchor section located at the bottom of the ring beam is enlarged to ensure sufficient anchoring force.

[0076] This embodiment achieves the following effects through prestressed support and cable-stayed reinforcement without requiring in-house installation:

[0077] (1) Safety performance: The load-bearing capacity of the walls of the first to third floors of the building meets the standards, the seismic performance is improved by more than 30%, and the requirements for subsequent years of use are met;

[0078] (2) Construction impact: The entire construction was carried out outside the building, without disturbing residents' lives by entering their homes, and there were no relocation, resettlement, or decoration compensation costs.

[0079] (3) Economic efficiency: The total reinforcement cost is only about 50% of the cost of traditional door-to-door reinforcement;

[0080] (4) Construction period: The entire process from inspection to acceptance took 2 months, which is 50% shorter than the traditional door-to-door reinforcement (4 months).

[0081] This embodiment fully demonstrates that the method described in this invention can effectively improve the safety of old brick-concrete structure houses without disturbing residents' lives, and has significant technical, economic and social value.

[0082] Although the present invention has been disclosed above with reference to embodiments, it is not intended to limit the present invention. Any person skilled in the art can make various different choices and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention is defined by the claims and their equivalents: prestressed jacking and outer cable tensioning are both within the scope of protection of the present invention.

Claims

1. A method for reinforcing existing brick-concrete structures without entering the building using a combination of prestressed support and cable tensioning, characterized in that... Includes the following steps: (1) Preliminary inspection and scheme design: Inspect the current status of the building structure, measure the plan layout and wall verticality, determine the location of the support and cable tension points and the load distribution ratio; use structural calculation software to simulate the stress state, optimize the parameters of external support and cable tension, and form "one building, one scheme"; (2) Installation of the support system: Anchor piles are constructed on the outside of the building and preloaded and sealed. Concrete support columns are poured and positions for hydraulic jacks are reserved. The ring beam under the extended load-bearing wall is extended above. Hydraulic jacks are installed in the gap between the extended ring beam and the outer support components to provide a source of prestress. (3) Cable system construction: Using directional drilling technology, drill holes along the designed trajectory from the outdoor incident point to the anchorage section under the ring beam of the indoor load-bearing wall at the set angle, orientation and diameter; if necessary, use bottom hole enlargement technology to enlarge the diameter of the anchorage end to the target diameter; install anchor cables; inject anchoring material into the anchorage section; perform prestressing tensioning and anchor sealing; and fill the entire borehole with secondary grouting. (4) Cooperative stress of prestressed support and cable tension: The external support structure is constructed from bottom to top. After each layer is constructed, the prestressed support of that layer is completed before constructing the layer above it. This process is repeated to complete the construction of the external support structure unit and its prestressed support. The prestressed cable tension is constructed from top to bottom. After the prestress of that layer is tensioned, locked, and the anchoring material is injected for the second time, the prestressed cable tension of the next layer is constructed. This process is repeated to complete the construction of the prestressed cable tension on the same external support structure unit. Each prestressed support and cable tension is precisely measured to ensure that the load distribution between the two reaches the design value. (5) Monitoring and acceptance: Install displacement sensors and stress gauges to monitor the stress and strain of the structure in real time during the reinforcement process, and adjust the cable prestress value in an information-based manner to meet the requirements.

2. The method according to claim 1, characterized in that, In the preliminary testing and scheme design, the building structure is a brick-concrete structure house that relies on brick walls for load-bearing and concrete floor slabs or precast slabs as horizontal components. Its seismic performance, crack resistance and durability are relatively weak.

3. The method according to claim 2, characterized in that, In the preliminary testing and scheme design, the brick-concrete structure with 24 walls that are load-bearing and have insufficient vertical component bearing capacity generally has ring beams, and structural columns may or may not be present.

4. The method according to claim 1, characterized in that, During the installation of the lifting system, the pile foundation of the supporting structure adopts anchor static pressure piles, and the pile, pile cap parameters and load-bearing sealing parameters are designed according to the reaction force at the bottom of the supporting structure column and the geological conditions.

5. The method according to claim 1, characterized in that, During the installation of the lifting system, prestressed support components are installed on the outer side of the building's exterior walls or column bases. Prestress is applied by hydraulic jacks, causing the support structure to generate an upward lifting force, which directly shares the load of the walls, beams, and slabs.

6. The method according to claim 1, characterized in that, The incident point is located on the outside of the load-bearing wall, and inclined directional holes are drilled inward according to the design parameters. If necessary, the holes are enlarged in the planned anchoring section. The holes are suspended downward to the bottom of the ring beam by steel cables, and prestress is applied by tensioning the anchor cables to transfer the equivalent lifting load generated by the cables to the external support structure.

7. The method according to claim 1, characterized in that, In the prestressed jacking and cable tensioning, the jacking system uses hydraulic jacks to apply prestress, which causes the supporting structure to generate an upward jacking force, directly sharing the load of the wall, beam, and slab. The cable tensioning system generates an upward component force through the prestress applied by the anchor cable tensioning, which, together with the lifting force, transfers the prestress to the vertical support members, reducing the stress level of the original structure.

8. The method according to claim 1, characterized in that, During the monitoring and acceptance process, the monitoring data from displacement sensors and stress gauges are used to determine whether the structural deformation is within the allowable range, facilitating information-based control of the prestress application value and ensuring that the reinforcement meets the design requirements.

9. The method according to claim 1, characterized in that, The method is applicable to old residential buildings with brick-concrete or frame structures where earthquake resistance or load-bearing capacity needs to be improved but residents have not been relocated; protective renovation scenarios where the original interior appearance needs to be preserved during the reinforcement of historical buildings; and scenarios where the reinforcement of street-facing buildings needs to avoid affecting commercial operations during construction.

Images