Construction structure for adding underground floors to existing buildings based on original pile replacement

Abstract

The construction structure for adding underground floors to existing buildings based on the original pile underpinning includes a new pile foundation cap fixed to the original engineering piles, and frame columns located above the new pile foundation cap and attached to the original engineering piles. The new pile foundation cap includes a bottom cushion layer and a brick formwork set on the bottom cushion layer. The brick formwork on all four sides is fixed to the bottom cushion layer to form the space for pouring concrete for the foundation. It also includes circumferential steel members, a reinforcement layer, and water-swellable waterstops. The circumferential steel members are fixed to the original engineering piles, and the reinforcement layer is welded to the circumferential steel members on both sides. Two water-swellable waterstops are fixed to the original engineering piles and are respectively set in the middle and lower middle parts of the new pile foundation cap. The application of T-shaped circumferential steel members and the reasonable use of steel bar welding and anchoring techniques in this application make the new structure and the original structure form an integral whole, improving the overall integrity and load-bearing capacity of the structure and meeting the requirements for underground floor addition.

Description

Technical Field

[0001] This application pertains to the field of building construction, specifically to the construction of underground additions to existing buildings based on the replacement of original piles. Background Technology

[0002] With the acceleration of urbanization and the increasing scarcity of urban land resources, the development and utilization of underground space in existing buildings has become particularly important. Numerous technical challenges exist in adding underground floors to existing buildings. Traditional construction methods often require extensive demolition of the original structure, resulting in resource waste, serious environmental problems, long construction periods, and high costs. Furthermore, how to achieve underground floor addition without compromising the structural safety of the existing building, ensuring a reliable connection between the new and existing structures, and guaranteeing the structural stability and waterproofing performance of the added floors are urgent problems to be solved.

[0003] (1) Safety assurance of existing building structure: During the construction of underground floors, it is necessary to ensure that the superstructure of the existing building is not affected during and after construction, so as to avoid structural deformation, cracking or even collapse caused by construction.

[0004] (2) Reliability of connection between new and old structures: The newly added underground structure needs to be firmly connected with the existing building's pile foundation, abutment and other structures to ensure the integrity and load-bearing capacity of the entire structural system. (3) Structural stability and waterproof performance issues.

[0005] (3) After the underground layer is added, it is necessary to ensure that the new structure has sufficient stability and good waterproof performance to prevent groundwater leakage from affecting the structural safety and functionality. Utility Model Content

[0006] The purpose of this utility model is to provide a construction structure for adding underground floors to existing buildings based on original pile underpinning, in order to solve the problems mentioned in the background art.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] The construction structure for adding underground floors to existing buildings based on the original pile underpinning method is characterized by: including a newly added pile foundation cap fixed on the original engineering piles, and a frame column located above the newly added pile foundation cap and attached to the original engineering piles. The newly added pile foundation cap includes a bottom cushion layer and a brick formwork set on the bottom cushion layer. The brick formwork on all four sides is fixed to the bottom cushion layer to form a concrete pouring space for the foundation. It also includes a circumferential steel member, a reinforcing steel layer, and water-swellable waterstop strips. The circumferential steel member is fixed to the original engineering piles, and the reinforcing steel layer is welded to the circumferential steel member on both sides. The two water-swellable waterstop strips are fixed to the original engineering piles and are respectively set in the middle and lower middle parts of the newly added pile foundation cap.

[0009] More preferably, an additional basement floor slab is provided between adjacent newly added pile foundation caps, the additional basement floor slab including a cushion layer and a foundation waterproof slab provided on the cushion layer.

[0010] Furthermore, the circumferential steel component is fixed to the original engineering pile using special structural adhesive. The circumferential steel component is formed by welding three T-shaped circumferential steel plates, with oblique cuts at both ends of the T-shaped circumferential steel plates.

[0011] Furthermore, the T-shaped circumferential steel plate includes a vertical circumferential plate that fits onto the original engineering pile and a horizontal plate located in the middle of the outer wall of the vertical circumferential plate. The horizontal plate is welded and fixed to the reinforcing steel layer.

[0012] Furthermore, the water-swellable sealing strip is ring-shaped and is fixed to the original engineering pile by U-shaped clips and steel nails.

[0013] Furthermore, the top surface of the foundation waterproof slab is flush with the top surface of the newly added pile foundation cap.

[0014] In addition, the frame column includes anchor bars that are set perpendicular to the outer wall of the original engineering pile and enlarged section column reinforcement bars and concrete connected to the anchor bars. The total length of the anchor bars is 200mm, and they are inserted into the original engineering pile by 100mm.

[0015] More preferably, the two circumferential steel members are respectively provided on the upper and lower parts of the newly added pile foundation, and the top surface of the upper circumferential steel member and the bottom surface of the lower circumferential steel member are respectively flush with the top and bottom surfaces of the newly added pile foundation.

[0016] Compared with the prior art, this utility model has the following features and beneficial effects:

[0017] Achieving a reliable connection between the old and new structures: The application of T-shaped circumferential steel components and the rational use of steel bar welding and anchoring techniques have enabled the new structure to form an integral whole with the original structure, improving the overall integrity and load-bearing capacity of the structure and meeting the requirements for underground floor additions.

[0018] Ensuring structural stability and waterproofing performance: The added pile foundation cap and raft slab (foundation waterproofing slab) increase foundation rigidity and improve structural stability. The installation of expansion sealing strips and strict concrete construction techniques effectively prevent groundwater leakage, ensuring the waterproofing performance of the underground layer and creating favorable conditions for subsequent use.

[0019] Significant economic benefits: This method makes full use of existing engineering piles and structures, reduces earthwork excavation and structural demolition, saves labor, materials, and machinery, and greatly improves construction efficiency. Compared with the traditional anchor-driven static pressure pile replacement method, it can save a lot of costs and has significant economic benefits.

[0020] Significant social benefits: The underground addition of floors without demolishing the original building preserves the original building's appearance, makes rational use of urban underground space, and meets the increased demand. It is of great significance for alleviating urban land shortages and improving land utilization, and has broad social benefits. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the construction structure for adding underground floors to an existing building based on the original pile underpinning method in this application.

[0022] Figure 2 This diagram illustrates the positional relationship between the newly added pile caps and the original piles involved in this application.

[0023] Figure 3 This diagram illustrates the positional relationship between the anchor bars involved in this application and the original engineering piles.

[0024] Attached reference numerals: 1-Original engineering pile; 2-New pile foundation cap; 21-Bottom cushion layer; 22-Brick formwork; 23-Pile cap concrete; 24-Circumferential steel member; 25-Reinforcing steel layer; 26-Water-swellable sealing strip; 3-Frame column; 31-Anchor bar; 32-Enlarged cross-section column reinforcement bar; 4-Additional basement floor slab; 41-Cushion layer; 42-Foundation waterproof slab. Detailed Implementation

[0025] To make the technical means, innovative features, objectives and effects of this utility model easier to understand, the utility model will be further described below.

[0026] The embodiments described herein are specific implementations of this utility model, used to illustrate the concept of this utility model. They are all illustrative and exemplary, and should not be construed as limiting the implementation methods or scope of this utility model. In addition to the embodiments described herein, those skilled in the art can employ other obvious technical solutions based on the content disclosed in the claims and specification of this application. These technical solutions include those that make any obvious substitutions and modifications to the embodiments described herein.

[0027] Example 1

[0028] The underground addition structure of an existing building based on the original pile underpinning includes a new pile cap 2 fixed to the original engineering pile 1, and a frame column 3 located above the new pile cap 2 and attached to the original engineering pile 1. The new pile cap 2 includes a bottom cushion 21 and a brick formwork 22 set on the bottom cushion 21. The four sides of the brick formwork 22 are fixed to the bottom cushion 21 to form the space for pouring the pile cap concrete 23. The new pile cap 2 also includes a circumferential steel member 24, a steel reinforcement layer 25, and a water-swellable... Waterstop strip 26 and circumferential steel member 24 are fixed to the original engineering pile 1. The steel reinforcement layer 25 is welded to the circumferential steel member 24 on both sides. Two water-swellable waterstop strips 26 are fixed to the original engineering pile 1 and are respectively set in the middle and lower middle parts of the newly added pile foundation 2. The steel reinforcement layer 25 is a rectangular structure with an overall shape that matches the shape of the foundation. It is poured into concrete. Each side of the steel reinforcement layer includes horizontal and vertical steel bars. The outside of the steel reinforcement layer is a concrete protective layer. The basement floor slab and the basement beam are connected between the newly added pile foundation 2.

[0029] An additional basement slab 4 is provided between adjacent newly added pile caps 2. The additional basement slab 4 includes a cushion layer 41 and a foundation waterproof slab 42 (raft slab) on the cushion layer 41. The circumferential steel member 24 is fixed to the original engineering pile 1 by special structural adhesive. The circumferential steel member 24 is formed by welding three T-shaped circumferential steel plates. The two ends of the T-shaped circumferential steel plate are beveled. The T-shaped circumferential steel plate includes a vertical circumferential plate that fits with the original engineering pile 1 and a horizontal plate located in the middle of the outer wall of the vertical circumferential plate. The horizontal plate is welded and fixed to the reinforcing steel layer 25. The water-swellable waterstop strip 26 is annular and is fixed to the original engineering pile 1 by several U-shaped clips and steel nails. The U-shaped clips hold the water-swellable waterstop strip 26 and are fixed to the original engineering pile 1 by steel nails.

[0030] The top surface of the foundation waterproof base plate 42 is flush with the top surface of the newly added pile foundation cap 2. The frame column 3 includes anchor bars 31 set perpendicular to the outer wall of the original engineering pile 1, and enlarged section column reinforcement bars 32 connected to the anchor bars 31 and concrete. The anchor bars 31 have a total length of 200mm and are inserted into the original engineering pile 1 by 100mm. Two circumferential steel members 24 are respectively set at the upper and lower parts of the newly added pile foundation cap 2. The top surface of the upper circumferential steel member 24 and the bottom surface of the lower circumferential steel member 24 are flush with the top and bottom surfaces of the newly added pile foundation cap 2, respectively. The upper part of the enlarged section column reinforcement bar 32 is anchored into the original pile cap, and the lower part is anchored into the newly added pile foundation cap 2.

[0031] Example 2

[0032] Construction method for adding underground floors to existing buildings based on original pile replacement:

[0033] (1) Safety assurance measures for existing building structures

[0034] This application utilizes the existing engineering piles as a vertical support system: the existing engineering piles are tested to ensure their bearing capacity meets the load requirements of the underground layer addition. During construction, the construction load is strictly controlled to avoid excessive impact on the existing engineering piles;

[0035] A segmented, layered, and symmetrical earthwork excavation method was adopted: by establishing an earth pressure calculation model, the characteristics of unbalanced excavation of existing building pile foundations were analyzed to ensure the stability of the pile foundation under unbalanced excavation conditions. It was determined that segmented and layered excavation would be adopted, with each layer not exceeding 2m in thickness, and the excavation would be advanced from the side in a stepped manner to ensure symmetrical excavation.

[0036] Real-time monitoring of structural deformation: During the construction process, the structural deformation of the existing building is monitored in real time, including settlement, displacement, cracks, etc. Once an abnormality is found, reinforcement measures are taken in a timely manner.

[0037] (2) Reliability measures for the connection between the old and new structures

[0038] 1) T-shaped circumferential steel component connection: Based on the diameter of the original engineering pile, T-shaped circumferential steel components are prefabricated in the factory and installed at the junction of the pile body and the new pile cap. The T-shaped circumferential steel component is deepened into three sections, and each section is welded together. One side of each section is deepened into a bevel to ensure welding quality. Special structural adhesive is injected into the gap between the steel component and the pile body to ensure a firm connection.

[0039] 2) Reinforcing bar welding and anchoring technology: The reinforcing bars of the newly added pile cap are welded to the T-shaped circumferential steel members on both sides, with a weld length of not less than 5d. In the pile-to-column conversion construction, anchoring technology is used to anchor the longitudinal reinforcement of the column into the original pile cap. Before anchoring, positioning and layout are carried out and reinforcement detection is performed to ensure accurate drilling positions. The anchoring adhesive is fully injected. After the anchoring is completed, a pull-out test is performed to ensure the anchoring quality.

[0040] (3) Measures to ensure structural stability and waterproof performance

[0041] 1) Add pile foundation caps and raft slabs: Pile foundation caps are installed at the new basement foundation location, along with a foundation raft slab (waterproof slab) to increase the overall rigidity and stability of the foundation. The reinforcement of the pile caps and raft slabs is arranged and tied according to design requirements to ensure the load-bearing capacity of the structure.

[0042] 2) Installation of expansion waterstop strips: Install two water-swellable waterstop strips in the middle and lower part of the pile cap respectively. Before installation, clean the dust off the pile body surface. Press the waterstop strip tightly against the pile body evenly and fix it with steel nails to increase the waterproof performance of the foundation.

[0043] 3) Concrete Construction and Curing: Before pouring concrete, remove debris, loose sand, and laitance from the joints, rinse thoroughly with water, and moisten completely. Use a method of "sloping layering, thin-layer pouring, and cyclical overall advancement" for concrete pouring, ensuring compaction and avoiding defects such as honeycomb and pitting. After pouring, promptly carry out curing for at least 14 days to ensure the concrete strength meets design requirements.

[0044] The foregoing has shown and described the basic principles, main features, and advantages of this utility model. It will be apparent to those skilled in the art that this utility model is not limited to the details of the exemplary embodiments described above, and that it can be implemented in other specific forms without departing from the spirit or basic characteristics of this utility model. Therefore, the embodiments should be considered exemplary and non-limiting in all respects. The scope of this utility model is defined by the appended claims rather than the foregoing description, and thus all variations falling within the meaning and scope of equivalents of the claims are intended to be included within this utility model. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0045] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A construction structure for adding underground floors to existing buildings based on original pile underpinning, characterized in that: The new pile foundation (2) is fixed on the original engineering pile (1) and a frame column (3) located above the new pile foundation (2) and attached to the original engineering pile (1). The new pile foundation (2) includes a bottom cushion layer (21) and a brick formwork (22) set on the bottom cushion layer (21). The brick formwork (22) on all four sides is fixed on the bottom cushion layer (21) to form a space for pouring concrete (23) of the foundation. The new pile foundation (23) also includes a circumferential steel member (24), a steel reinforcement layer (25) and a water-swellable waterstop strip (26). The circumferential steel member (24) is fixed on the original engineering pile (1). The steel reinforcement layer (25) is welded to the circumferential steel member (24) on both sides. The two water-swellable waterstop strips (26) are fixed on the original engineering pile (1) and are respectively set in the middle and lower part of the new pile foundation (2).

2. The construction structure for adding underground floors to existing buildings based on original pile underpinning as described in claim 1, characterized in that: An additional basement floor slab (4) is provided between adjacent newly added pile foundation caps (2). The additional basement floor slab (4) includes a cushion layer (41) and a foundation waterproof slab (42) provided on the cushion layer (41).

3. The construction structure for adding underground floors to existing buildings based on original pile underpinning as described in claim 1, characterized in that: The circumferential steel component (24) is fixed to the original engineering pile (1) by special structural adhesive. The circumferential steel component (24) is formed by welding three T-shaped circumferential steel plates. The two ends of the T-shaped circumferential steel plates are oblique cuts.

4. The construction structure for adding underground floors to existing buildings based on original pile underpinning as described in claim 1, characterized in that: The T-shaped circumferential steel plate includes a vertical circumferential plate that fits onto the original engineering pile (1) and a horizontal plate located in the middle of the outer wall of the vertical circumferential plate. The horizontal plate is welded and fixed to the reinforcing steel layer (25).

5. The construction structure for adding underground floors to existing buildings based on original pile underpinning as described in claim 1, characterized in that: The water-swellable sealing strip (26) is ring-shaped and is fixed to the original engineering pile (1) by U-shaped clips and steel nails.

6. The construction structure for adding underground floors to existing buildings based on original pile underpinning as described in claim 1, characterized in that: The top surface of the foundation waterproof base plate (42) is flush with the top surface of the newly added pile foundation cap (2).

7. The construction structure for adding underground floors to existing buildings based on original pile underpinning as described in claim 1, characterized in that: The frame column (3) includes anchor bars (31) set perpendicular to the outer wall of the original engineering pile (1) and expanded section column reinforcement bars (32) connected to the anchor bars (31) and concrete. The anchor bars (31) are 200mm long and 100mm embedded in the original engineering pile (1).

8. The construction structure for adding underground floors to existing buildings based on original pile underpinning as described in any one of claims 1 to 7, characterized in that: The two circumferential steel members (24) are respectively located on the upper and lower parts of the newly added pile foundation cap (2), and the top surface of the upper circumferential steel member (24) and the bottom surface of the lower circumferential steel member (24) are respectively flush with the top and bottom surfaces of the newly added pile foundation cap (2).

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