CN117248530A - Joint construction device and construction method for adding elevator foundation pit structure to existing building - Google Patents

Abstract

The invention provides a conjuncted construction device and a construction method for an existing building additionally provided with an elevator foundation pit structure, wherein the conjuncted construction device comprises a foundation pit which is arranged on a foundation, a lifting structure layer is erected at the bottom of the foundation pit, a cement cover plate is paved on the periphery of a fourth lifting structure layer, an outer membrane wallboard is erected at the edge of an inner ring of the cement cover plate, an outer layer gallery is formed by the surrounding of the inner wall of the foundation pit, the cement cover plate and the outer membrane wallboard, backfill is filled in the outer layer gallery, a vertical steel bar frame is arranged in the outer membrane wallboard Zhou Bang, a steel inner membrane square box is arranged in the inner periphery of the vertical steel bar frame, a plurality of height adjusting support legs are connected at the bottom of the inner membrane square box, the height adjusting support legs are inserted into the lifting structure layer, and the vertical steel bar frame and the lifting structure layer are integrally constructed by pouring concrete. According to the invention, the supporting edge is adopted for backfilling and one-time pouring operation is carried out, so that good foundation strength, waterproof compactness of a foundation pit are realized, the construction cost is saved, the construction efficiency is improved, and the construction period is shortened.

Description

Joint construction device and construction method for adding elevator foundation pit structure to existing building

Technical field

The invention belongs to the technical field of civil engineering, and relates to the construction of an elevator foundation, in particular to a joint construction device and a construction method for adding an elevator foundation pit structure to an existing building.

Background technique

With the advancement of urbanization and population growth, the installation of elevators in existing buildings has become an important demand to improve the transportation convenience of old urban buildings. However, due to the constraints of the old building structure and limited space, the traditional method of installing elevators may require large-scale demolition and reconstruction projects, which will bring high costs and great inconvenience. It will also cause damage to the original building structure and Users pose risks.

To address these issues, researchers and engineers have been working to develop new construction techniques and devices to efficiently and safely add elevators to existing buildings. One of the innovative solutions is the conjoined construction unit, which enables the installation of elevators by integrating the foundation pit with the existing building, thereby avoiding the hassle of large-scale demolition and reconstruction.

However, in practical applications, conjoined construction devices still face some challenges and technical difficulties. One of them is how to ensure the construction safety and structural stability of the elevator installation. Due to the uncertainty of the structural conditions of the existing building and the geological conditions of the soil, the device needs to be able to adapt to various complex situations and ensure construction safety during the construction process.

In addition, the construction process of adding an elevator also needs to meet technical requirements and relevant regulations, such as elevator operation stability, load-bearing capacity, waterproof performance, etc. Various pipelines are buried underground in front of existing building units, such as heating pipelines, gas pipelines, water pipelines, sewage pipelines, weak current pipelines, etc. The large number of pipelines makes excavation more difficult. The larger the excavation size of the foundation pit, the higher the difficulty. At the same time, it has a direct impact on the cost of the pipelines. Using traditional construction, you need to excavate and pour the floor concrete first, and then start to tie the vertical steel bars around the walls and start supporting the internal/external formwork. Therefore, a foundation pit foundation needs to be constructed with a high-mixing truck twice, which not only increases the construction cost, but also delays the construction progress.

Contents of the invention

The purpose of the present invention is to solve the above-mentioned problems in the existing technology and propose a joint construction device for adding an elevator pit structure to an existing building to achieve the integrated formation of the floor and the surrounding wall through one pouring, thereby improving the construction efficiency.

The object of the present invention can be achieved through the following technical solutions: a joint construction device for adding an elevator foundation pit structure to an existing building, which includes a foundation pit excavated on the foundation, and a high-ceiling structural layer is erected at the bottom of the foundation pit. , lay a cement cover plate around the perimeter of the elevated structure layer 4, and erect an outer membrane wall panel on the inner edge of the cement cover plate. The inner wall of the foundation pit, the cement cover plate and the outer membrane The wall panels are surrounded to form an outer corridor, and the outer corridor is filled with backfill soil. A vertical steel frame is tied around the inner periphery of the outer membrane wall panels, and a steel inner membrane square box is placed around the inner periphery of the vertical steel frame. , the bottom of the inner membrane square box is connected with a number of height-adjusting legs, the height-adjusting legs are inserted into the high-ceiling structural layer, and the vertical steel frame and the concrete poured in the high-ceiling structural layer form an integrated structure.

In the above-mentioned joint construction device for adding an elevator foundation pit structure to an existing building, the elevated structural layer includes a bottom frame of horizontal and vertical ribs laid flat on the bottom of the pit, and the outer periphery of the bottom frame of horizontal and vertical ribs is in contact with the The inner peripheral walls of the foundation pit are connected through brick partitions, and the brick partitions include a plurality of bricks.

In the above-mentioned joint construction device for adding an elevator pit structure to an existing building, the cement cover plate is covered above the brick partition, and the inner ring of the cement cover plate is overlapped with the horizontal and vertical bars. above the outer perimeter of the bottom frame.

In the above-mentioned joint construction device for adding an elevator pit structure to an existing building, the outer membrane wall panels include a number of hollow panels spliced together from bottom to top, and the outer membrane wall panels circle to form a square wall structure.

In the above-mentioned joint construction device for adding an elevator pit structure to an existing building, the vertical steel bar frame includes a square frame steel bar structure formed by binding a number of vertical bars, and a number of square frame steel bar structures are connected in the corners. A screw rod, the penetrating ends of several of the screw rods are connected to the right-angle embedded parts, the upper section of the screw rod is sleeved with a fixing nut, and the fixed nut presses the right-angled embedded parts.

In the above-mentioned joint construction device for adding an elevator pit structure to an existing building, the inner membrane square box includes a square cylinder box surrounded by steel formwork on four sides, and the inner right-angled sides of the right-angle embedded parts are Lean against the corner outer wall of the square tube box.

In the above-mentioned joint construction device for adding an elevator pit structure to an existing building, reinforcing components are assembled inside the square cylindrical box. The reinforcing components include several angle steels. The edges between each two adjacent steel formworks are Several angle steels are fixed longitudinally and parallel to each other.

In the above-mentioned joint construction device for adding an elevator pit structure to an existing building, the height-adjusting legs include inverted adjusting bolts, and an adjusting nut is sleeved on the upwardly erected screw rod of the adjusting bolt. The square cylinder A sleeve is correspondingly fixed on the bottom edge of the box, and the sleeve is sleeved on the top of the screw and carried on the adjusting nut.

A construction method for a joint construction device for adding an elevator foundation pit structure to an existing building, including the following steps:

S1. Excavate a square foundation pit, set up a circle of brick partitions at the bottom of the foundation pit along the pit wall, and tie a horizontal and vertical reinforced bottom frame around the inner periphery of the brick partitions;

S2. Set up a cement cover plate on the top surface of the brick partition and the peripheral edge of the horizontal and vertical rib bottom frame, fix the outer membrane wall panel on the inner edge of the square-shaped cement cover plate, and place it between the pit wall and the outer membrane wall panel. The corridor between rooms is filled with backfill soil;

S3. Bind the vertical steel frame to the inner periphery of the outer membrane wall panel. Insert a number of screw rods into each corner of the vertical steel frame. Place right-angle embedded parts on each corner to connect with several screw rods. The top of the screw rods are socketed and fixed. Nut and lock the right-angle embedded parts;

S4. Place the inner membrane square box on the inner periphery of the vertical steel frame, and twist the adjusting nut to adjust the height and level of the inner membrane square box;

S5. Concrete is poured from the top of the vertical steel frame between the outer membrane wall panel and the inner membrane square box until the concrete flows to fill the bottom frame of horizontal and vertical ribs and the vertical steel frame;

S6. After the concrete is completely solidified, remove the inner membrane square box to separate the sleeve from the adjusting bolt. The adjusting bolt remains in the concrete, and the construction of the elevator foundation pit is completed.

In the above-mentioned construction method of a joint construction device for adding an elevator pit structure to an existing building, in step S2, a layer of hollow plates is erected around the inner edge of the cement cover plate, and a hollow plate is placed on the top edge of the hollow plate. Installation slot, the bottom edge of the hollow board is provided with a protruding installation strip. Through the insertion and matching of the installation strip and the installation slot, the second layer of hollow boards is overlapped on the first layer of hollow board, and the overlap is completed in sequence until the required height is reached.

Compared with the existing technology, the joint construction device and construction method of adding an elevator foundation pit structure to an existing building have the following beneficial effects:

1. This construction method uses supporting edge backfilling and one-time pouring operations to achieve good foundation strength and waterproof tightness of the foundation pit, thereby saving construction costs, improving construction efficiency, and shortening the construction period.

2. By using this joint construction device and method, elevators can be quickly and efficiently added to existing buildings without the need for large-scale reconstruction of the building, which helps to improve the function and value of existing buildings in the city.

3. By establishing a strong bottom frame and walls in the foundation pit and using concrete to form an integrated fixed structure, the stability and load-bearing capacity of the elevator foundation pit are ensured, thereby improving the quality and safety of the entire structure.

4. The use of lightweight materials such as hollow slabs and angle steel, as well as intelligent joint construction devices, can reduce the labor and material costs required for construction. In addition, it also reduces large-scale damage and reconstruction of buildings, thus saving time and resources. .

5. Through the design of the elevated structure and outer corridor, the water tightness of the structure can be effectively improved, the risk of groundwater penetration can be reduced, and the dryness and stability of the elevator foundation pit can be ensured.

6. The use of components such as height-adjusting legs and inner membrane square boxes can achieve precise control of the height and level of the structure, ensuring the accuracy and controllability of the construction process.

7. By using lightweight materials and reducing the need for building modifications, the negative impact on the environment is reduced, while the life of existing buildings is extended and sustainability is improved.

To sum up, when using this patent to install an elevator in an existing building, construction workers can operate more conveniently, reduce damage to the original building, and improve the safety and reliability of the construction. The device's innovation, reliability and efficiency give it a wide range of application prospects and can meet the needs of urban development and renovation of old buildings. This patent makes the installation of elevators more convenient, faster and feasible, providing urban residents with a more comfortable and convenient way to travel.

Description of drawings

Figure 1 is an overall three-dimensional structural view of the joint construction device for adding an elevator pit structure to an existing building.

Figure 2 is an internal three-dimensional structural view of the joint construction device for adding an elevator pit structure to an existing building.

Figure 3 is an overall upward structural view of the joint construction device for adding an elevator pit structure to an existing building.

Figure 4 is an internal front structural view of the joint construction device for adding an elevator pit structure to an existing building.

In the picture, 1. Foundation; 2. Brick partition; 3. Bottom frame with horizontal and vertical reinforcements; 4. Cement cover; 5. Backfill; 6. Hollow slab; 7. Vertical steel frame; 8. Screw rod; 9. Right-angle embedded parts; 10. Fixing nut; 11. Inner membrane square box; 12. Angle steel; 13. Sleeve; 14. Adjusting bolt.

Detailed ways

The following are specific embodiments of the present invention combined with the accompanying drawings to further describe the technical solution of the present invention, but the present invention is not limited to these embodiments.

Embodiment 1

As shown in Figures 1 to 4, this joint construction device for adding an elevator foundation pit structure to an existing building includes a foundation pit excavated on foundation 1, a high-rise structural layer set up at the bottom of the foundation pit, and The cement cover plate 4 is laid on the periphery of the fourth layer, and an outer membrane wall panel is erected on the inner edge of the cement cover plate 4. An outer corridor is formed by the inner wall of the foundation pit, the cement cover plate 4 and the outer membrane wall panel. The backfill soil 5 is filled in, and a vertical steel frame 7 is tied around the inner periphery of the outer membrane wall panel. A steel inner membrane square box 11 is inserted into the inner periphery of the vertical steel frame 7. A number of height-adjusting feet are connected to the bottom of the inner membrane square box 11. The high legs are inserted into the high-ceiling structural layer, and the vertical steel frame 7 and the concrete poured in the high-ceiling structural layer form an integrated structure.

The elevated structural layer includes a horizontal and vertical reinforced bottom frame 3 laid flat on the bottom of the foundation pit. The outer periphery of the horizontal and vertical reinforced bottom frame 3 and the inner peripheral wall of the foundation pit are connected through a brick partition 2. The brick partition 2 includes a number of bricks.

The cement cover plate 4 is placed above the brick partition 2, and the inner ring of the cement cover plate 4 is overlapped above the outer periphery of the horizontal and vertical rib bottom frame 3. The outer part of the cement cover plate 4 overlaps the brick partition 2, and the inner part of the cement cover plate 4 overlaps the horizontal and vertical rib bottom frame 3, thereby extending the pouring space to the bottom of the cement cover plate 4 to form a hollow structure. . Through the hollow structure, the poured concrete is extended to the bottom of the cement cover plate 4, thereby improving the stability, load-bearing strength and dense waterproofing of the poured foundation 1.

The outer membrane wall panel includes a number of hollow panels 6 spliced together from bottom to top, and is surrounded by a circle of outer membrane wall panels to form a square wall structure. The hollow board 6 has the characteristics of high strength and light weight. The support strength of the backfill soil 5 is achieved through the support assembly of the hollow board 6. Using the hollow board 6 as the main body of the outer membrane wall panel can not only ensure the strength requirements, but also reduce the weight of the wall. The body weight is reduced, the excavation size is reduced, and installation and construction are facilitated.

The vertical steel frame 7 includes a square frame steel structure formed by binding a number of vertical bars. Several screw rods 8 are connected in the corners of the square frame steel bar structure, and the outgoing ends of the several screw rods 8 are connected to right-angle embedded parts 9 , the upper section of the screw rod 8 is sleeved with a fixing nut 10, and the fixing nut 10 presses the right-angle embedded part 9. The vertical bars are tied to form an overall square frame structure, and the right-angle embedded parts 9 at the four corners are fixed and installed through the locking cooperation of the screw rod 8 and the fixing nut 10, further improving the stability and strength of the overall vertical steel frame 7.

The inner membrane square box 11 includes a square cylinder box surrounded by steel formwork on four sides, and the inner right-angled edge of the right-angle embedded part 9 is close to the corner outer wall of the square cylinder box. The square cylindrical box is assembled with four right-angled embedded parts 9 to form a plane positioning, thereby ensuring the accurate position of the inner membrane and the accurate angle of the inner membrane wall.

Reinforcement components are assembled in the square tube box. The reinforcement components include several angle steels 12, and several angle steels 12 are fixed longitudinally and parallel between each adjacent two steel formwork pieces. The two ends of the angle steel 12 are connected to the inner wall of the steel formwork by welding. The angle between the angle steel 12 and the steel formwork is 45°. The structure is connected through a large number of multi-layer hooks of the angle steel 12, which is supported by the inside of the square tube box. Strengthen the support strength of the surrounding wall of the square cylinder box to ensure the flatness of the inner membrane wall.

The height-adjusting legs include an inverted adjusting bolt 14. The adjusting bolt 14 is socketed with an adjusting nut on the upwardly erected screw rod. A corresponding fixed sleeve 13 is installed on the bottom edge of the square tube box. The sleeve 13 is socketed with the top of the screw rod and is carried on the on the adjusting nut. A total of 8 sleeves 13 are provided on the bottom edge of the square tube box, and 8 adjusting bolts 14 are connected to each other one by one. By screwing 8 adjusting nuts, the height of the 8 sleeves 13 is adjusted to ensure the levelness and height requirements of the square tube box, that is, to complete the required raft thickness elevation. There is a sleeve annular gap left between the sleeve 13 and the screw, so that when the square cylinder box is pulled out, the sleeve 13 can be separated from the screw.

Embodiment 2

Based on Embodiment 1, the differences of this embodiment are:

A construction method for a joint construction device for adding an elevator foundation pit structure to an existing building, including the following steps:

S1. Dig a square foundation pit, set a circle of brick partitions 2 around the bottom of the foundation pit along the pit wall, and tie a horizontal and vertical reinforced bottom frame 3 around the inner periphery of the brick partitions 2;

S2. Set up a cement cover plate 4 on the top surface of the brick partition 2 and the circumferential edges of the horizontal and vertical rib bottom frame 3. Fix the outer membrane wall panel on the inner edge of the square-shaped cement cover plate 4, facing the pit wall and the outside. The corridor between the membrane wall panels is filled with backfill soil 5;

S3. Bind the vertical steel frame 7 to the inner periphery of the outer membrane wall panel. Insert several screw rods 8 into each corner of the vertical steel frame 7. Place right-angle embedded parts 9 on each corner and connect them with several screw rods 8. The top of the rod 8 is sleeved with the fixing nut 10 and locked with the right-angle embedded part 9;

S4. Place the inner membrane square box 11 on the inner periphery of the vertical steel frame 7, and twist the adjusting nut to adjust the height and level of the inner membrane square box 11;

S5. Concrete is poured from the top of the vertical steel frame 7 between the outer membrane wall panel and the inner membrane square box 11 until the concrete flows to fill the horizontal and vertical rib bottom frame 3 and the vertical steel frame 7; the elevator foundation pit is formed through the horizontal and vertical rib bottom frame 3. The bottom plate forms the surrounding wall panels of the elevator foundation pit through the vertical steel frame 7. After the pouring is completed, the bottom plate and the surrounding wall panels form an integrated fixed structure through concrete;

S6. After the concrete is completely solidified, remove the inner membrane square box 11 so that the sleeve 13 is separated from the adjusting bolt 14, and the adjusting bolt 14 remains in the concrete. The construction of the elevator foundation pit is completed.

In step S2, a layer of hollow plate 6 is erected around the inner edge of the cement cover plate 4. A mounting groove is recessed on the top edge of the hollow plate 6, and a mounting strip is protruding on the bottom edge of the hollow plate 6. Through the mounting strip and The installation grooves are inserted and matched, and the second layer of hollow boards 6 are overlapped on the first layer of hollow boards 6, and the joints are overlapped in sequence until the required height is reached.

A square wall structure is formed by surrounding the hollow plates 6 on four sides, and each two adjacent hollow plates 6 are connected at right angles. Specifically, a cross-jointed butt-joining method is adopted. For example, one side of the hollow plate 6 has an upper notch and a lower protrusion, and the adjacent surface of the hollow plate 6 has an upper protrusion and a lower notch correspondingly, so that the two are butted together so that the upper protrusion and the upper notch are combined, and the lower protrusion is combined with the lower notch. , thereby improving the stability of vertical docking.

Compared with the existing technology, the joint construction device and construction method of adding an elevator foundation pit structure to an existing building have the following beneficial effects:

1. This construction method uses supporting edge backfilling and one-time pouring operations to achieve good foundation strength and waterproof tightness of the foundation pit, thereby saving construction costs, improving construction efficiency, and shortening the construction period.

2. By using this joint construction device and method, elevators can be quickly and efficiently added to existing buildings without the need for large-scale reconstruction of the building, which helps to improve the function and value of existing buildings in the city.

3. By establishing a strong bottom frame and walls in the foundation pit and using concrete to form an integrated fixed structure, the stability and load-bearing capacity of the elevator foundation pit are ensured, thereby improving the quality and safety of the entire structure.

4. The use of lightweight materials such as hollow slabs and angle steel, as well as intelligent joint construction devices, can reduce the labor and material costs required for construction. In addition, it also reduces large-scale damage and reconstruction of buildings, thus saving time and resources. .

5. Through the design of the elevated structure and outer corridor, the water tightness of the structure can be effectively improved, the risk of groundwater penetration can be reduced, and the dryness and stability of the elevator foundation pit can be ensured.

6. The use of components such as height-adjusting legs and inner membrane square boxes can achieve precise control of the height and level of the structure, ensuring the accuracy and controllability of the construction process.

7. By using lightweight materials and reducing the need for building modifications, the negative impact on the environment is reduced, while the life of existing buildings is extended and sustainability is improved.

To sum up, when using this patent to install an elevator in an existing building, construction workers can operate more conveniently, reduce damage to the original building, and improve the safety and reliability of the construction. The device's innovation, reliability and efficiency give it a wide range of application prospects and can meet the needs of urban development and renovation of old buildings. This patent makes the installation of elevators more convenient, faster and feasible, providing urban residents with a more comfortable and convenient way to travel.

The specific embodiments described herein are merely illustrative of the spirit of the invention. Those skilled in the art to which the present invention belongs can make various modifications or additions to the described specific embodiments or substitute them in similar ways, but this will not deviate from the spirit of the present invention or exceed the definition of the appended claims. range.

Although this article mostly uses foundation 1; brick partition 2; horizontal and vertical reinforced bottom frame 3; cement cover plate 4; backfill soil 5; hollow slab 6; vertical steel frame 7; screw rod 8; right-angle embedded parts 9; Fixed nut 10; inner membrane square box 11; angle steel 12; sleeve 13; adjusting bolt 14 and other terms, but the possibility of using other terms is not excluded. These terms are used only to more conveniently describe and explain the essence of the present invention; interpreting them as any additional limitations is contrary to the spirit of the present invention.

In the description of the present invention, it should be noted that, unless otherwise clearly stated and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense. For example, it can be a fixed connection or a detachable connection. Connection, or integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be an internal connection between two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood on a case-by-case basis.

Claims (10)

1. A joint construction device for adding an elevator foundation pit structure to an existing building, which includes a foundation pit excavated on the foundation. It is characterized in that a raised structural layer is set up at the bottom of the foundation pit, and a raised structural layer is set up at the bottom of the foundation pit. A cement cover plate is laid around the periphery of the fourth structural layer, and an outer membrane wall panel is erected on the inner edge of the cement cover plate. The outer wall is formed by the inner wall of the foundation pit, the cement cover plate and the outer membrane wall panel. The outer corridor is filled with backfill soil, the inner periphery of the outer membrane wall panel is tied with a vertical steel frame, and the inner periphery of the vertical steel frame is placed with a steel inner membrane square box. The inner membrane square box is A number of height-adjusting legs are connected to the bottom of the box, and the height-adjusting legs are inserted into the elevated structural layer. The vertical steel frame and the concrete poured in the elevated structural layer form an integrated structure. 2. The joint construction device for adding an elevator foundation pit structure to an existing building as claimed in claim 1, characterized in that the high-ceiling structural layer includes a bottom frame of horizontal and vertical ribs laid flat on the bottom of the foundation pit, so The outer periphery of the horizontal and vertical reinforced bottom frame and the inner peripheral wall of the foundation pit are connected through a brick partition, and the brick partition includes a plurality of bricks. 3. The joint construction device for adding an elevator foundation pit structure to an existing building as claimed in claim 2, characterized in that the cement cover plate is installed above the brick partition, and the cement cover plate is The inner ring overlaps above the outer periphery of the horizontal and vertical rib bottom frame. 4. The combined construction device for adding an elevator pit structure to an existing building as claimed in claim 1, characterized in that the outer membrane wall panels include a number of hollow panels spliced from bottom to top, and the outer membrane wall panels The enclosure forms a square wall structure. 5. The combined construction device for adding an elevator foundation pit structure to an existing building as claimed in claim 1, characterized in that the vertical steel bar frame includes a square frame steel bar structure formed by binding a number of vertical bars, and the square steel bar structure is Several screw rods are connected in the corners of the frame steel structure, and the outgoing ends of the screw rods are connected to right-angle embedded parts. The upper section of the screw rod is sleeved with a fixing nut, and the fixed nut presses the right-angle Embedded parts. 6. The joint construction device for adding an elevator foundation pit structure to an existing building as claimed in claim 5, wherein the inner membrane square box includes a square tube box surrounded by steel formwork on four sides. The inner right-angled edge of the right-angle embedded part is close to the corner outer wall of the square cylinder box. 7. The joint construction device for adding an elevator pit structure to an existing building as claimed in claim 6, characterized in that reinforcing components are assembled inside the square tube box, and the reinforcing components include several angle steels, each adjacent Several angle steels are fixed longitudinally and parallel between the two steel formwork pieces. 8. The joint construction device for adding an elevator pit structure to an existing building as claimed in claim 6, characterized in that the height-adjusting legs include inverted adjusting bolts, and the adjusting bolts are upwardly erected on the screw rods. The adjusting nut is sleeved, and a sleeve is correspondingly fixed on the bottom edge of the square tube box. The sleeve is sleeved on the top of the screw and is carried on the adjusting nut. 9. A construction method for a joint construction device for adding an elevator foundation pit structure to an existing building, which is characterized by including the following steps: S1. Excavate a square foundation pit, set up a circle of brick partitions at the bottom of the foundation pit along the pit wall, and tie a horizontal and vertical reinforced bottom frame around the inner periphery of the brick partitions; S2. Set up a cement cover plate on the top surface of the brick partition and the peripheral edge of the horizontal and vertical rib bottom frame, fix the outer membrane wall panel on the inner edge of the square-shaped cement cover plate, and place it between the pit wall and the outer membrane wall panel. The corridor between rooms is filled with backfill soil; S3. Bind the vertical steel frame to the inner periphery of the outer membrane wall panel. Insert a number of screw rods into each corner of the vertical steel frame. Place right-angle embedded parts on each corner to connect with a number of screw rods. The top of the screw rods are socketed and fixed. Nut and lock the right-angle embedded parts; S4. Place the inner membrane square box on the inner periphery of the vertical steel frame, and twist the adjusting nut to adjust the height and level of the inner membrane square box; S5. Concrete is poured from the top of the vertical steel frame between the outer membrane wall panel and the inner membrane square box until the concrete flows to fill the bottom frame of horizontal and vertical ribs and the vertical steel frame; S6. After the concrete is completely solidified, remove the inner membrane square box to separate the sleeve from the adjusting bolt. The adjusting bolt remains in the concrete, and the construction of the elevator foundation pit is completed. 10. The construction method of a joint construction device for adding an elevator pit structure to an existing building as claimed in claim 9, characterized in that, in step S2, a layer of hollow slabs is erected around the inner edge of the cement cover plate. , a mounting groove is recessed on the top edge of the hollow board, and a mounting strip is protruding on the bottom edge of the hollow board. Through the insertion and mating of the mounting bar and the mounting groove, the second-layer hollow board is overlapped on the first-layer hollow board, and the two-layer hollow boards are overlapped in sequence. until the desired height is reached.