CN118498528A - A modular composite steel-concrete building unit and its production method and installation method - Google Patents

Abstract

The invention discloses a modularized superposed steel-concrete building unit, a production method and an installation method thereof, wherein the steel-concrete building unit comprises upright posts, top beams, bottom beams and beam-to-beam assemblies; the top beam is H-shaped steel, and two ends of the top beam are welded with the upright posts; the bottom beam is a steel-concrete beam, two ends of the bottom beam are welded with the upright posts; the inter-beam assembly comprises an outer sleeve and an inner sleeve, the outer sleeve is welded at the bottom of the bottom beam, the inner sleeve is welded at the top of the top beam, and when one steel-concrete building unit is stacked on the other steel-concrete building unit, the upper outer sleeve is sleeved on the lower inner sleeve. When the steel-concrete building unit is applied, the steel-concrete beams with concrete are adopted as the bottom beams when bearing pressure load, so that the advantage of strong compressive capacity of the concrete is fully utilized, and the problem that the traditional steel-structure modularized building is insufficient in rigidity and easy to tremble is solved.

Description

A modular composite steel-concrete building unit and its production method and installation method

Technical Field

The invention relates to the field of construction, and in particular to a modular composite steel-concrete building unit and a production method and an installation method thereof.

Background Art

The construction method of modular construction (MIC) is to split the building into modular "building units", efficiently complete the construction processes of the building unit's structure, decoration, water and electricity, equipment pipelines, bathroom facilities, etc. in the factory, and then quickly assemble the whole building on site through reliable connection technology. This modular construction method moves the building from the construction site to the factory, greatly shortens the construction period, reduces the difficulty of construction, and realizes "building a house like building a car". It is currently the most industrialized green construction method.

The existing mainstream structural forms of modular buildings are mainly divided into two types: precast concrete structure and steel structure. The former is widely used in prefabricated residential buildings due to its low cost and good comfort. Its disadvantages are bulkiness and poor connection performance. The latter is easy to achieve large span and large space layout due to its light weight, high strength and easy installation. It is mostly used in public buildings. Its disadvantages are weak rigidity, vibration and poor comfort. Another disadvantage is that the latter is mostly steel frame structure. Steel columns and steel beams will protrude from the building walls or floor slabs as structural members, lowering the net height and affecting the building plan. These pain points hinder the application of steel structure modular buildings.

Summary of the invention

The technical problem to be solved by the present invention is that the prefabricated concrete modular buildings in the prior art are bulky and have poor connection performance, while the steel structure modular buildings have weak rigidity, are prone to vibration during use, and have poor comfort.

In order to solve the above technical problems, the technical solution adopted by the present invention is: a modular composite steel-concrete building unit, including columns, top beams, bottom beams and inter-beam components;

The top beam is an H-shaped steel, and both ends of the top beam are welded to the columns;

The bottom beam is a steel-concrete beam (i.e., a PEC beam), including an H-shaped steel and concrete poured on both sides of the H-shaped steel web, and both ends of the bottom beam are welded to the columns;

The inter-beam component includes an outer sleeve and an inner sleeve, wherein the outer sleeve is welded to the bottom of the bottom beam and the inner sleeve is welded to the top of the top beam. When one steel-concrete building unit is stacked on top of another steel-concrete building unit, the upper outer sleeve is sleeved on the lower inner sleeve.

The steel-concrete building units of the present invention are stacked and installed when used, with one steel-concrete building unit superimposed on another steel-concrete building unit. The inter-beam assembly allows the bottom beam of the upper steel-concrete building unit and the top beam of the lower steel-concrete building unit to be superimposed together to form a whole beam that bears force together. Its bearing capacity and rigidity are greater than those of two separate beams. When bearing pressure loads, since the bottom beam adopts a steel-concrete beam with concrete (PEC beam), the advantage of the strong compressive resistance of concrete is fully utilized, and the problem of insufficient rigidity and easy vibration of traditional steel structure modular buildings is solved. On the other hand, the combination of the bottom beam (steel-concrete beam) and the top beam (pure steel beam) in the present invention still maintains the advantage of strong connection performance compared to traditional prefabricated concrete structure modular buildings, and its own weight also has an advantage.

Specifically, the inter-beam assembly further includes bolts, lining plates and nuts, the lining plates are welded to the inner surface of the inner sleeve, the surface of the outer sleeve is provided with a first through hole, the surface of the inner sleeve is provided with a second through hole, the surface of the lining plates is provided with a third through hole, and the nut is welded at the third through hole on the surface of the lining plates; when the outer sleeve is sleeved on the inner sleeve, the first through hole, the second through hole and the third through hole are aligned, the bolts pass through the first through hole, the second through hole and the third through hole and connect the nuts, locking the inner sleeve and the outer sleeve; the inter-beam assembly is used to realize the connection of two steel-concrete building units superimposed on each other, in the production stage, the inner sleeve and the outer sleeve will be welded to the top beam and the bottom beam respectively, and during on-site installation, it is only necessary to insert the inner sleeve and the outer sleeve and then install the bolts;

In order to facilitate installation, the dimensions of the inner sleeve and the outer sleeve should satisfy the following requirements: when the outer sleeve is inserted into the inner sleeve, there is a gap between the outer sleeve and the inner sleeve.

Specifically, the column is made of steel square tube, and the square cross-section column is convenient for welding with the top beam and the bottom beam; on the other hand, in order to ensure the strength of the welding position, the inner cavity at both ends of the column is provided with a horizontal stiffening plate, and the position of the horizontal stiffening plate is aligned with the wing plate of the H-shaped steel of the top beam and the bottom beam.

The present invention also provides a method for producing a modular composite steel-concrete building unit, comprising the following steps:

Step 1: Cut steel square tubes of appropriate size, process them into columns, outer sleeves and inner sleeves, weld lining plates inside the inner sleeves, and weld horizontal stiffening plates at the inner cavities at both ends of the columns. The positions of the horizontal stiffening plates should be reasonably set to ensure that the horizontal stiffening plates are in the same horizontal plane as the flanges of the top beam and bottom beam subsequently welded on the columns. The horizontal stiffening plates are welded to the inner cavity of the columns through groove penetration welding, and the thickness of the horizontal stiffening plates should not be less than the thickness of the flanges of the corresponding top beam or bottom beam;

Step 2: Cut H-shaped steel of appropriate size to be used as top and bottom beams;

Step 3: Weld multiple inner sleeves on the upper surface of the top beam, and weld multiple outer sleeves on the lower surface of the bottom beam; generally, multiple inner sleeves are arranged in a row along the length direction of the top beam and are evenly spaced. The number and spacing of the inner sleeves should be obtained by mechanical calculation based on the size, weight and other parameters of the building; the number and arrangement of the outer sleeves correspond to the inner sleeves one by one;

Step 4: Pour concrete on one side of the web of the H-shaped steel of the bottom beam, and reserve a non-casting node area of a set length at both ends of the H-shaped steel. The non-casting node area is used for subsequent welding of the bottom beam and the column;

Step 5: Weld the top beam and bottom beam to the columns to form a box-shaped frame; after the bottom beam is welded, pour concrete in the non-casting node area.

Furthermore, the production method of the modular composite steel-concrete building unit also includes:

Step 6: Tie the floor slab steel bars, bend and anchor the floor slab steel bars to the unconcreted area on the web side of the H-shaped steel of the bottom beam, and then pour the floor slab concrete. The floor slab concrete enters the belly cavity of the bottom beam, so that the PEC bottom beam and the floor slab form a whole.

Furthermore, the production method of the modular composite steel-concrete building unit also includes:

Step 7: Install the wall on the floor. The wall can be various prefabricated walls in the prior art, such as light steel keel walls. The specific method is to pre-assemble C-shaped keels into keel wall panels, pre-embed pipelines and insulation layers inside the wall panels, and finally embed the wall panels into the frame formed by beams and columns.

When installing the steel-concrete building unit of the present invention, the outer sleeves and inner sleeves of the upper and lower steel-concrete building units need to be completely aligned, and then inserted and fixed; due to the large number of outer sleeves and inner sleeves, it is very difficult to ensure the alignment of multiple outer sleeves and multiple inner sleeves in practical applications, which requires the installation of each outer sleeve and inner sleeve to be precisely positioned, which places high demands on welding workers. In order to improve welding efficiency, the present invention improves the welding method of the outer sleeve and the inner sleeve in step 3, and the specific method of step 3 is:

Step 3-1: Weld multiple inner sleeves on the upper surface of the top beam. The multiple inner sleeves are arranged in a row along the length direction of the top beam and are evenly spaced. The number and spacing of the inner sleeves should be obtained by mechanical calculation based on the size, weight and other parameters of the building. In this step, workers only need to use a tape measure to roughly control the spacing between the inner sleeves, and do not need to spend too much effort on precise positioning;

Step 3-2: insert an auxiliary pin into the first through hole of the outer sleeve, the auxiliary pin comprising a pin shaft and a top cap arranged at one end of the pin shaft, the middle of the pin shaft is provided with a groove having a width equal to the wall thickness of the inner sleeve; the four vertical surfaces of the outer sleeve with a rectangular cross-section need to be inserted with the auxiliary pin;

Step 3-3: half of the outer sleeve is inserted into the inner sleeve, and the groove of the auxiliary pin inserted into the first through hole is stuck in the upper edge of the inner sleeve; the distance between the groove of the auxiliary pin and the top cap should ensure that: after the outer sleeve is half-inserted into the inner sleeve, the gap between the outer sleeve and the inner sleeve is equal to the set gap;

Steps 3-4: stack the H-shaped steel of the bottom beam on the outer casing, and then weld the bottom beam and the outer casing;

Steps 3-5: Separate the bottom beam and the top beam, number the bottom beam and the top beam, and use the bottom beam and the top beam in two steel-concrete building units in an upper and lower relationship respectively.

In the above step 3 of the present invention, the inner sleeves and outer sleeves on the top beam and the bottom beam are essentially inserted into each other first, and then the outer sleeves are welded to the bottom beam; this ensures that when the subsequent steel-concrete building units are installed, the outer sleeves and inner sleeves of the upper and lower steel-concrete building units must be aligned and can be inserted into each other successfully (because the outer sleeves and inner sleeves have been aligned and welded in the production stage). However, this production method also determines that the produced steel-concrete building units must be installed strictly according to the designed position and cannot be arbitrarily replaced.

The present invention also provides an installation method for modular composite steel-concrete building units, which specifically comprises the following steps: hoisting a steel-concrete building unit to the top of another steel-concrete building unit, lowering the upper steel-concrete building unit, and sleeve- ing the outer sleeve under the bottom beam of the upper steel-concrete building unit onto the inner sleeve on the lower top beam; then inserting bolts from the first through holes of all the outer sleeves and locking the inner sleeves and the outer sleeves.

Furthermore, when installing the bolts, start tightening the bolts from the outer sleeve in the middle of the bottom beam, and then install other bolts in order from the middle to both ends. After all the bolts are installed, the columns of the upper steel-concrete building unit and the columns of the lower steel-concrete building unit are connected and fixed by bevel penetration welding; finally, an external curtain wall or a shaped gusset plate is used to cover the joints between adjacent steel-concrete building units.

Beneficial effects: (1) The steel-concrete building unit of the present invention utilizes a steel-concrete beam with concrete to bear the pressure load, making full use of the advantage of the strong compressive resistance of concrete, and solving the problem of insufficient rigidity and easy vibration of traditional steel structure modular buildings. (2) The steel-concrete building unit of the present invention uses an inner sleeve and an outer sleeve to connect the top beam and the bottom beam to form a new composite beam. Compared with the traditional prefabricated concrete structure modular building, it still maintains the advantage of strong connection performance and has its own weight advantage. (3) The steel-concrete building unit of the present invention pre-inserts the top beam and the bottom beam during production, ensuring that when the subsequent steel-concrete building unit is installed, the outer sleeve and the inner sleeve of the upper and lower steel-concrete building units must be aligned and can be successfully inserted.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a structural diagram of a steel-concrete building unit according to an embodiment.

FIG. 2 is a front view of the steel-concrete building unit of the embodiment.

Fig. 3 is a cross-sectional view taken along line A-A of Fig. 2 .

FIG. 4 is an enlarged view of A in FIG. 3 .

FIG. 5 is an enlarged view of B in FIG. 3 .

FIG. 6 is a structural diagram of an inter-beam assembly in an embodiment.

FIG. 7 is a parts diagram of the outer sleeve in the embodiment.

FIG8 is a structural diagram of an inner sleeve, a liner and a nut in an embodiment.

FIG. 9 is a structural diagram of a liner and a nut in an embodiment.

FIG. 10 is an exploded view of the columns and horizontal stiffening plates in the embodiment.

FIG. 11 is a schematic diagram of the installation of the steel-concrete building unit of the embodiment.

FIG. 12 is a welding flow chart (part 1) of the inner sleeve and the outer sleeve in the embodiment.

FIG. 13 is a welding flow chart of the inner sleeve and the outer sleeve in the embodiment (part 2).

FIG. 14 is a welding flow chart of the inner sleeve and the outer sleeve in the embodiment (part 3).

15 is a welding flow chart of the inner sleeve and the outer sleeve in the embodiment (fourth).

FIG. 16 is a parts diagram of the auxiliary pin in the embodiment.

Among them: 100, column; 110, horizontal stiffening plate; 200, top beam; 300, bottom beam; 400, beam assembly; 410, outer sleeve; 411, first through hole; 420, inner sleeve; 421, second through hole; 430, bolt; 440, lining plate; 441, third through hole; 450, nut; 500, floor; 600, wall; 700, auxiliary pin; 710, pin shaft; 720, top cap; 730, groove.

DETAILED DESCRIPTION

The present invention is further described in detail below in conjunction with specific implementation modes.

Example

As shown in FIGS. 1 to 10 , the modular composite steel-concrete building unit of this embodiment includes a column 100 , a top beam 200 , a bottom beam 300 , an inter-beam assembly 400 , a floor slab 500 and a wall 600 .

As shown in FIG. 4 , the top beam 200 is an H-shaped steel, and both ends of the top beam 200 are welded to the column 100 ; as shown in FIG. 5 , the bottom beam 300 is a steel-concrete beam (i.e., a PEC beam), including an H-shaped steel and concrete poured on both sides of the H-shaped steel web, and both ends of the bottom beam 300 are welded to the column 100 .

As shown in Figures 6 to 9, the inter-beam assembly 400 includes an outer sleeve 410, an inner sleeve 420, bolts 430, a lining plate 440 and a nut 450. The outer sleeve 410 is welded to the bottom of the bottom beam 300, and the inner sleeve 420 is welded to the top of the top beam 200. When one steel-concrete building unit is stacked on top of another steel-concrete building unit, the upper outer sleeve 410 is sleeved on the lower inner sleeve 420. The lining plate 440 is welded to the inner surface of the inner sleeve 420, the surface of the outer sleeve 410 is provided with a first through hole 411, the surface of the inner sleeve 420 is provided with a second through hole 421, the surface of the lining plate 440 is provided with a third through hole 441, and the nut 450 is welded at the third through hole 441 on the surface of the lining plate 440; when the outer sleeve 410 is sleeved on the inner sleeve 420, the first through hole 411, the second through hole 421 and the third through hole 441 are aligned, the bolt 430 passes through the first through hole 411, the second through hole 421 and the third through hole 441 and is connected to the nut 450, locking the inner sleeve Tube 420 and outer sleeve 410; the beam assembly 400 is used to connect two steel-concrete building units stacked up and down. During the production stage, the inner sleeve 420 and the outer sleeve 410 will be welded to the top beam 200 and the bottom beam 300 respectively. During on-site installation, it is only necessary to insert the inner sleeve 420 and the outer sleeve 410 and then install the bolt 430; for easy installation, the dimensions of the inner sleeve 420 and the outer sleeve 410 should meet the following requirements: when the outer sleeve 410 is inserted into the inner sleeve 420, there is a gap between the outer sleeve 410 and the inner sleeve 420, and the gap is designed to be 2 mm in this embodiment.

As shown in Figure 10, the column 100 is made of a steel square tube. The square cross-section of the column 100 is convenient for welding with the top beam 200 and the bottom beam 300. On the other hand, in order to ensure the strength of the welding position, the inner cavity at both ends of the column 100 is provided with a horizontal stiffening plate 110, and the position of the horizontal stiffening plate 110 is aligned with the wing plate of the H-shaped steel of the top beam 200 and the bottom beam 300.

As shown in FIG. 5 , the floor slab 500 is aligned with the bottom beam 300 , and the concrete of the floor slab 500 will enter the belly cavity of one side of the H-shaped steel of the bottom beam 300 during pouring, so that the PEC bottom beam 300 and the floor slab 500 form a whole.

The wall 600 in this embodiment can be various prefabricated walls in the prior art, such as a light steel keel wall. The specific method is to pre-assemble C-shaped keels into keel wall panels, pre-embed pipelines and insulation layers inside the wall panels, and finally embed the wall panels into a frame composed of beams and columns.

The installation method of the steel-concrete building unit of this embodiment is as follows: as shown in FIG. 11, a steel-concrete building unit is hoisted to the top of another steel-concrete building unit, the upper steel-concrete building unit is lowered, the outer sleeve 410 under the bottom beam 300 of the upper steel-concrete building unit covers the inner sleeve 420 on the lower top beam 200, and then the bolts 430 are inserted from the first through holes 411 of all the outer sleeves 410 and the inner sleeves 420 and the outer sleeves 410 are locked. When installing the bolts 430, the bolts 430 are tightened from the outer sleeve 410 in the middle of the bottom beam 300, and then other bolts 430 are installed in the order from the middle to the two ends. After all the bolts 430 are installed, the columns 100 of the upper steel-concrete building unit and the columns 100 of the lower steel-concrete building unit are connected and fixed by groove penetration welding; finally, the joints between adjacent steel-concrete building units are covered by external curtain walls or shaped gussets. After the steel-concrete building unit is installed, the state of the beam assembly 400 between the upper and lower steel-concrete building units will be as shown in FIG. 6 , where the outer sleeve 410 and the inner sleeve 420 are inserted into each other and fixed by bolts 430 .

The modular composite steel-concrete building units of this embodiment are all prefabricated in the factory and then transported to the construction site for installation. The specific production method is:

Step 1: Cut steel square tubes of appropriate size, process them into columns 100, outer sleeves 410 and inner sleeves 420, weld lining plates 440 inside the inner sleeves 420, weld horizontal stiffening plates 110 at the inner cavities at both ends of the columns 100, and the positions of the horizontal stiffening plates 110 should be reasonably set to ensure that the horizontal stiffening plates 110 and the flanges of the top beam 200 and the bottom beam 300 subsequently welded on the columns 100 are in the same horizontal plane, and the horizontal stiffening plates 110 are welded to the inner cavity of the columns 100 by groove penetration welding, and the thickness of the horizontal stiffening plates 110 should not be less than the thickness of the flanges of the corresponding top beam 200 or bottom beam 300;

Step 2: Cut H-shaped steel of appropriate size to be used as the top beam 200 and the bottom beam 300;

Step 3: Weld a plurality of inner sleeves 420 on the upper surface of the top beam 200, and weld a plurality of outer sleeves 410 on the lower surface of the bottom beam 300; generally, the plurality of inner sleeves 420 are arranged in a row along the length direction of the top beam 200 and are evenly spaced, and the number and spacing of the inner sleeves 420 should be obtained by mechanical calculation based on parameters such as the size and weight of the building; the number and arrangement of the outer sleeves 410 correspond to the inner sleeves 420 one by one;

Step 4: pour concrete on one side of the web of the H-shaped steel of the bottom beam 300, and reserve a non-casting node area of a set length at both ends of the H-shaped steel, and the non-casting node area is used for subsequent welding of the bottom beam 300 and the column 100;

Step 5: Weld the top beam 200 and the bottom beam 300 to the column 100 to form a box-shaped frame; after the bottom beam 300 is welded, pour concrete in the non-casting node area;

Step 6: Tie the steel bars of the floor slab 500, bend and anchor the steel bars of the floor slab 500 to the unconcreted area on the web side of the H-shaped steel of the bottom beam 300, and then pour the concrete of the floor slab 500, so that the concrete of the floor slab 500 enters the belly cavity of the bottom beam 300, so that the PEC bottom beam 300 and the floor slab 500 form a whole;

Step 7: Install the wall 600 on the floor 500. The wall 600 can be various prefabricated walls in the prior art, such as a light steel keel wall. The specific method is to pre-assemble C-shaped keels into keel wall panels, pre-embed pipelines and insulation layers inside the wall panels, and finally embed the wall panels into a frame formed by beams and columns.

In the production method of this embodiment, the welding of the inner sleeve 420 and the outer sleeve 410 in step 3 is directly related to whether the inner sleeve 420 and the outer sleeve 410 can be smoothly inserted during the subsequent installation of the steel-concrete building unit. Therefore, all the inner sleeves 420 and the outer sleeve 410 in step 3 need to be accurately positioned, which is very time-consuming. In order to improve the efficiency of step 3, this embodiment improves step 3. The specific method of step 3 is:

Step 3-1: As shown in FIG. 12 , a plurality of inner sleeves 420 are welded on the upper surface of the top beam 200 . The plurality of inner sleeves 420 are arranged in a row along the length direction of the top beam 200 and are evenly spaced. The number and spacing of the inner sleeves 420 should be obtained by mechanical calculation based on parameters such as the size and weight of the building. In this step, the worker only needs to use a tape measure to roughly control the spacing between the inner sleeves 420 , and does not need to spend too much effort on precise positioning.

Step 3-2: insert the auxiliary pin 700 into the first through hole 411 of the outer sleeve 410. The structure of the auxiliary pin 700 is shown in FIG. 16, including a pin shaft 710 and a top cap 720 arranged at one end of the pin shaft 710. The middle of the pin shaft 710 is provided with a groove 730 with a width equal to the wall thickness of the inner sleeve 420. The four vertical surfaces of the outer sleeve 410 with a rectangular cross-section need to be inserted with the auxiliary pin 700.

Step 3-3: As shown in FIGS. 13 and 14 , the outer sleeve 410 is half-inserted into the inner sleeve 420, and the groove 730 of the auxiliary pin 700 inserted into the first through hole 411 is stuck in the upper edge of the inner sleeve 420; the distance between the groove 730 of the auxiliary pin 700 and the top cap 720 should ensure that: after the outer sleeve 410 is half-inserted into the inner sleeve 420, the gap between the outer sleeve 410 and the inner sleeve 420 is equal to the set gap;

Step 3-4: As shown in FIG. 15 , the H-shaped steel of the bottom beam 300 is stacked on the outer sleeve 410 , and then the bottom beam 300 and the outer sleeve 410 are welded;

Sub-steps 3-5: separate the bottom beam 300 and the top beam 200, number the bottom beam 300 and the top beam 200, and use the bottom beam 300 and the top beam 200 in two steel-concrete building units in an upper and lower relationship, respectively.

In the above specific step 3, the inner sleeve 420 and the outer sleeve 410 on the top beam 200 and the bottom beam 300 are first inserted into each other, and then the outer sleeve 410 is welded to the bottom beam 300; this ensures that when the subsequent steel-concrete building units are installed, the outer sleeve 410 and the inner sleeve 420 of the upper and lower steel-concrete building units must be aligned and can be inserted successfully (because the outer sleeve 410 and the inner sleeve 420 have been aligned and welded in the production stage). However, this production method also determines that the produced steel-concrete building units must be installed strictly according to the designed position and cannot be arbitrarily replaced.

Although the embodiments of the present invention are described in the specification, these embodiments are only for reference and should not limit the protection scope of the present invention. Various omissions, substitutions and changes within the scope of the present invention should be included in the protection scope of the present invention.

Claims (10)

1. A modular composite steel-concrete building unit, characterized by comprising columns, top beams, bottom beams and inter-beam components; The top beam is an H-shaped steel, and both ends of the top beam are welded to the columns; The bottom beam is a steel-concrete beam, including H-shaped steel and concrete poured on both sides of the H-shaped steel web, and both ends of the bottom beam are welded to the columns; The inter-beam component includes an outer sleeve and an inner sleeve, wherein the outer sleeve is welded to the bottom of the bottom beam and the inner sleeve is welded to the top of the top beam. When one steel-concrete building unit is stacked on top of another steel-concrete building unit, the upper outer sleeve is sleeved on the lower inner sleeve. 2. The modular composite steel-concrete building unit according to claim 1 is characterized in that: the inter-beam assembly further comprises bolts, lining plates and nuts, the lining plates are welded to the inner surface of the inner sleeve, the surface of the outer sleeve is provided with a first through hole, the surface of the inner sleeve is provided with a second through hole, the surface of the lining plates is provided with a third through hole, and the nut is welded at the third through hole on the surface of the lining plates; when the outer sleeve is sleeved on the inner sleeve, the first through hole, the second through hole and the third through hole are aligned, the bolts pass through the first through hole, the second through hole and the third through hole and connect with the nuts, locking the inner sleeve and the outer sleeve; When the outer sleeve is inserted into the inner sleeve, a gap is formed between the outer sleeve and the inner sleeve. 3. The modular composite steel-concrete building unit according to claim 2 is characterized in that: the columns are made of steel square tubes, and the inner cavities at both ends of the columns are provided with horizontal stiffening plates, and the positions of the horizontal stiffening plates are aligned with the wing plates of the H-shaped steel of the top beam and the bottom beam. 4. A method for producing a modular composite steel-concrete building unit as claimed in claim 2 or 3, characterized in that it comprises the following steps: Step 1: Cut the steel square tube of appropriate size, process it into columns, outer sleeves and inner sleeves, weld the lining plate inside the inner sleeve, and weld the horizontal stiffening plates at the inner cavities at both ends of the columns; Step 2: Cut H-shaped steel of appropriate size to be used as top and bottom beams; Step 3: Weld multiple inner sleeves on the upper surface of the top beam, and weld multiple outer sleeves on the lower surface of the bottom beam; Step 4: Pour concrete on one side of the web of the H-shaped steel of the bottom beam, and reserve a non-casting node area of a set length at both ends of the H-shaped steel. The non-casting node area is used for subsequent welding of the bottom beam and the column; Step 5: Weld the top beam and bottom beam to the columns to form a box-shaped frame; after the bottom beam is welded, pour concrete in the non-casting node area. 5. The method for producing modular composite steel-concrete building units according to claim 4, characterized in that it also includes: Step 6: Tie the floor slab reinforcement, bend and anchor the floor slab reinforcement to the unconcreted area on the web side of the H-shaped steel of the bottom beam, and then pour the floor slab concrete, and the floor slab concrete enters the belly cavity of the bottom beam. 6. The method for producing modular composite steel-concrete building units according to claim 5, characterized in that it also includes: Step 7: Install the wall above the floor. 7. The method for producing modular composite steel-concrete building units according to claim 6, characterized in that the specific steps of step 3 include: Sub-step 3-1: welding a plurality of inner sleeves on the upper surface of the top beam; Sub-step 3-2: inserting an auxiliary pin into the first through hole of the outer sleeve, the auxiliary pin comprising a pin shaft and a top cap arranged at one end of the pin shaft, and a groove having a width equal to the wall thickness of the inner sleeve is arranged in the middle of the pin shaft; Step 3-3: half-insert the outer sleeve into the inner sleeve, and the groove of the auxiliary pin inserted into the first through hole is stuck in the upper edge of the inner sleeve; the distance between the groove of the auxiliary pin and the top cap makes the gap between the outer sleeve and the inner sleeve equal to the set gap; Steps 3-4: stack the H-shaped steel of the bottom beam on the outer casing, and then weld the bottom beam and the outer casing; Steps 3-5: Separate the bottom beam and the top beam, number the bottom beam and the top beam, and use the bottom beam and the top beam in two steel-concrete building units in an upper and lower relationship respectively. 8. A method for installing modular composite steel-concrete building units as described in claim 2 or 3, characterized in that: one steel-concrete building unit is hoisted to the top of another steel-concrete building unit, the upper steel-concrete building unit is lowered, the outer sleeve under the bottom beam of the upper steel-concrete building unit is sleeved over the inner sleeve on the lower top beam, and then bolts are inserted from the first through holes of all the outer sleeves and the inner sleeves and outer sleeves are locked. 9. The installation method of modular composite steel-concrete building units according to claim 8 is characterized in that: when installing bolts, the bolts are tightened starting from the outer sleeve in the middle of the bottom beam, and then other bolts are installed in order from the middle to both ends. After all bolts are installed, the columns of the upper steel-concrete building units are welded to the columns of the lower steel-concrete building units. 10. The method for installing modular composite steel-concrete building units according to claim 9, characterized in that external curtain walls or shaped gussets are used to cover the joints between adjacent steel-concrete building units.