Construction method for newly-added fabricated staircase of reinforced concrete frame structure

Abstract

The invention discloses a construction method of a reinforced concrete frame structure newly-added fabricated staircase. The construction method comprises the steps of site survey and factory prefabrication; original local beam columns are reinforced according to the reinforcement and reinforcement scheme; two first anchor plates and two reinforcing steel beams are sequentially arranged on the two sides of an existing concrete beam reinforcing area, base plates are arranged between the reinforcing steel beams and a concrete floor, and then long screws are matched with cushion blocks and locking nuts to fix the two reinforcing steel beams to the two sides of an existing concrete beam; dismantling operation is conducted, and a hole space is formed in the concrete floor; for the steel columns in the first-layer building space, when the steel columns are located on the column net, the steel columns directly root on the first-layer foundation straining beams in the erecting process, and when the steel columns are not located on the column net, the steel columns are additionally used as foundations; the four new steel beams are arranged at the building position of the steel platform plate in a square shape; the steel platform plate is fixedly installed among the four new steel beams; and steel stairs are additionally arranged. According to the method, the implementation process is simple, the construction process is safe, and the newly-added operation of the assembly type stair can be efficiently completed.

Description

Technical Field

[0001] The invention belongs to the technical field of building engineering reinforcement, and specifically is a construction method for newly adding assembled stairs in a reinforced concrete frame structure. Background Art

[0002] As my country vigorously promotes prefabricated buildings, prefabricated components have gradually been promoted in the field of building reinforcement and renovation. Prefabricated buildings refer to buildings that transfer a large number of on-site operations in traditional construction methods to factories, process and manufacture building components and accessories (such as floor slabs, wall panels, stairs, balconies, etc.) in factories, transport them to construction sites, and assemble and install them on site through reliable connection methods. When renovating large space frame structures, due to changes in building functions, stairs must be added in special areas as important evacuation passages. Compared with concrete stairs, prefabricated steel structure stairs have the advantages of flexible layout, improved construction efficiency, and shortened overall construction period. Therefore, steel stairs, as a common component of prefabricated buildings, have played an increasingly important role in the process of renovating large space frame structures, and their popularity has gradually increased. However, in the process of adding prefabricated stairs, it is bound to destroy part of the original building structure, which will reduce the bearing capacity and safety performance of the original building structure. Therefore, in the process of adding prefabricated stairs, how to ensure the bearing capacity and safety performance of the original building structure has become a technical problem that needs to be solved urgently. Summary of the invention

[0003] In view of the problems existing in the above-mentioned prior art, the present invention provides a construction method for adding prefabricated stairs to a reinforced concrete frame structure. The method has a simple implementation process, a safe construction process, high construction efficiency, and a flexible construction method. The method can efficiently complete the addition of prefabricated stairs and is suitable for various building function transformation needs. It is not only suitable for the transformation and reinforcement projects of existing large-space frame structure buildings, but also suitable for staircase construction in newly built buildings, and has broad application prospects.

[0004] In order to achieve the above object, the present invention provides a construction method for a newly added assembled staircase in a reinforced concrete frame structure, comprising the following steps: Step 1: Site survey and factory prefabrication; S11: Conduct on-site surveys based on building functional requirements and the actual conditions of the building, and determine the areas on the concrete floor to be demolished; S12: Combined with the on-site survey, the original reinforced concrete frame structure is subjected to force analysis and calculation, and the reinforcement and reinforcement scheme of the local beams and columns outside the area to be demolished is determined based on the force analysis and calculation results to ensure that the installation process of the new staircase will not cause adverse effects on the original structure; based on the reinforcement and reinforcement scheme, the size of the reinforced steel beam, the size of the L-shaped angle steel, the size of the anchor plate, and the size of the pad required for the reinforcement of the existing concrete beam are determined; at the same time, based on the force analysis and calculation results, the size, structure, weight, bearing strength and installation position of the new steel staircase are determined, the size, structure, weight, bearing strength and installation position of the steel platform plate are determined, the size and bearing strength of the new steel beam are determined, and the size and bearing strength of the steel column are determined; S13: prefabricate reinforced steel beams, L-shaped angle steels, anchor plates 1, pads, steel stairs, steel columns, and steel platform plates in a factory, wherein the reinforced steel beams are made of I-shaped steels, and a pair of L-shaped angle steels are connected to both ends of the reinforced steel beams, and the transverse sections of the pair of L-shaped angle steels are relatively distributed on both sides of the web plate at the end of the reinforced steel beams. Each pair of L-shaped angle steels and the reinforced steel beams are fixedly connected to each other by a plurality of high-strength bolts 1 penetrating through the transverse sections of the two L-shaped angle steels and the web plate at the end of the reinforced steel beams. At the same time, a plurality of through holes A are opened on the longitudinal sections of the pair of L-shaped angle steels, and a plurality of through holes B are opened on the anchor plate 1; Step 2: Strengthen the original local beams and columns according to the reinforcement and reinforcement plan; The reinforcement process for the existing concrete beams at the edge of the area to be demolished is as follows: S21: Drill multiple screw installation holes in the reinforcement area on the existing concrete beam in the width direction; S22: two anchor plates 1 and two reinforced steel beams are arranged in sequence on both sides of the existing concrete beam reinforcement area, and two pads are arranged on the upper wing plates of the two reinforced steel beams and the bottom surface of the concrete floor slab, and then a plurality of long screws are passed through the plurality of screw installation holes, and the two ends of the screws are sequentially passed through the plurality of through holes B on the two anchor plates 1 and the plurality of through holes A on the longitudinal sections of the two pairs of L-shaped angle steels. Then, two pads and two sets of locking nuts are sequentially installed on the two ends of each long screw from the inside to the outside, and the two pairs of L-shaped angle steels are locked on both sides of the existing concrete beam reinforcement area by using the locking nuts, so as to fix the ends of the two reinforced steel beams that are close to each other to the two sides of the existing concrete beam; finally, for the ends of the two reinforced steel beams that are far away from each other, a plurality of chemical anchor bolts that pass through the longitudinal sections of a pair of L-shaped angle steels are used to fix them to the concrete columns or concrete beams at the opposite ends of the existing concrete beams; Step 3: Demolition of some areas of the existing concrete floor; Demolition work is performed on the area to be demolished on the concrete floor slab, and a hole space is formed on the concrete floor slab; Step 4: Add steel platform plate; S41: According to the determined steel platform slab construction position, four steel columns are erected at the four corners of the corresponding steel platform slab; during the steel column erection process, for the steel columns in the first-floor building space, when the steel columns are located on the column net, they are directly rooted on the first-floor foundation tie beam during the erection process. For the steel columns that are not on the column net, another foundation is made during the erection process. The foundation uses small-diameter bored piles, and steel pipes are inserted inside to replace steel bars. Cement mortar is then poured into the steel pipes so that the bearing layer at the pile end is coarse sand. At the same time, the pile side post-grouting technology is used to improve the compressive bearing capacity of the foundation; for the steel columns in the non-first-floor building space, professional hoisting equipment is used to hoist the steel columns to the upper-floor building space, and the steel columns are erected on the existing concrete beams or reinforced steel beams, and it is ensured that the steel columns are firmly connected to the steel bars in the concrete beams or the reinforced steel beams; S42: Use professional lifting equipment to lift four new steel beams to the required installation height, and arrange the four new steel beams in a square shape at the construction position of the steel platform plate. Then, fix the two ends of each new steel beam to the two adjacent steel columns respectively; S43: Fix and install the steel platform plate between the four new steel beams; Step 5: Add steel stairs; For the first section of steel stairs in the first floor building space, the second anchor plate is arranged at the bottom end of the first section of steel stairs, and the bottom end of the steel ladder beam of the first section of steel stairs is fixedly connected to the second anchor plate by using the first connecting plate, and then the second anchor plate is anchored to the surface of the concrete foundation by using the inverted cone chemical anchor bolt, and then the top end of the steel ladder beam of the first section of steel stairs is fixedly connected to the new steel beam at the location of the steel platform plate by using the second connecting plate; For the remaining steel stairs, they are installed section by section from bottom to top. During the installation process, professional lifting equipment is used to lift the steel stairs through the hole space to the corresponding building space on the upper floor, and the corresponding connection method is selected according to the position of the end of the steel stairs. When the end position of the steel stairs corresponds to the steel platform plate, the steel ladder beam at the end of the steel stairs is fixedly connected to the new steel beam at the location of the steel platform plate by using connecting plate 2. When the end position of the steel stairs corresponds to the edge of the hole space in the original reinforced concrete frame, the steel ladder beam at the end of the steel stairs is fixedly connected to the reinforced steel beam at the corresponding position by using connecting plate 3.

[0005] As a preferred embodiment, in step 1 S13, the steel column and the new steel beam are both made of I-beams.

[0006] Furthermore, in order to ensure the bearing capacity and durability so as to meet the strength and stability requirements of the newly added structural system, in step 1 S13, the new steel beams, reinforced steel beams and steel columns are all made of high-strength steel.

[0007] Preferably, in step 2 S22, the thickness of the cushion block is greater than 6 mm.

[0008] As a preferred embodiment, in step 2 S22, when installing anchor plate 1, ensure that the upper edge of anchor plate 1 is flush with the lower end surface of the concrete floor slab, and at the same time, ensure that the lower end edge of anchor plate 1 is flush with the lower end surface of the existing concrete beam.

[0009] As a preferred option, in step three, during the demolition process, use professional equipment to accurately cut out parts of the concrete floor slab, and strictly control the construction quality and safety to avoid unnecessary damage to the original building structure. At the same time, take noise reduction measures to reduce the impact on the surrounding environment and residents.

[0010] Furthermore, in order to significantly improve the connection strength between the long screw and the existing concrete beam, and to ensure that the subsequently installed reinforced steel beam can be stably and reliably connected to the existing concrete beam, in step two S22, high-strength grouting material or adhesive is poured into the gap between the long screw and the screw mounting hole.

[0011] Furthermore, in order to effectively improve the bearing strength of the existing concrete columns, in step two, the existing concrete columns are reinforced by adding steel bars or pasting steel plates or using carbon fiber composite materials.

[0012] In the present invention, before construction, the original reinforced concrete frame structure is first subjected to force analysis and calculation in combination with the on-site survey, so that the bearing capacity and weak links of the original reinforced concrete frame structure can be determined, and then the reinforcement and reinforcement scheme can be obtained in a targeted manner. At the same time, the position of the newly added steel staircase can be reasonably determined, ensuring the stability and safety of the original building structure after the newly added steel staircase. Before opening the hole space, the original reinforced concrete frame structure is first reinforced, so that it can be ensured that the opening of the hole space and the addition of the steel staircase will not cause adverse effects on the original building structure. In the process of reinforcing the existing concrete beam, two reinforced steel beams are added on both sides of the existing concrete beam, and the two reinforced steel beams are firmly connected to the two sides of the existing concrete beam by using multiple long screws, one anchor plate, two pairs of L-shaped angle steels and multiple sets of locking nuts, effectively connecting the two reinforced steel beams added later to the existing concrete beam stably into an integral structure, so that the force of the overall structure can be more reasonable, and the force requirements and stability requirements of the overall structure can be met under the loss of a certain strength of the original concrete beam. At the same time, the newly added reinforced steel beams greatly improve the bearing capacity and stability of local beams and columns outside the area to be demolished. This reinforcement method solves the problem that the existing connection method cannot achieve stable connection between the existing reinforced concrete beams and the newly added reinforced steel beams. While meeting the needs of the reinforcement function, it also ensures the strength and rigidity of the existing reinforced concrete beams. At the same time, this reinforcement method provides an effective solution for the integral connection of the reinforced steel beams on both sides and the coordinated force of the reinforced steel beams and the concrete floor slabs, ensuring the integrity and reliability of the reinforced structure. By opening the hole space, it is easy to lift the prefabricated steel stairs, steel platform plates, reinforced steel beams, steel columns, new steel beams and other components required for the renovation through the hole space to the superstructure space, improving the convenience during the construction process. New steel beams, steel platform plates, steel stairs, reinforced steel beams, L-shaped angle steels, anchor plates, pads, and steel columns are all prefabricated in the factory, then transported to the construction site, and then precisely assembled according to the design requirements to form a complete reinforced structure and steel staircase structure, effectively improving the construction efficiency and reducing the impact of the construction process on the site environment. Using multiple high-strength steel bolts to fix a pair of L-shaped angle steels on both sides of the web at the end of the reinforced steel beam not only makes the installation and disassembly process more convenient, but also ensures the firmness and reliability of the connection, effectively improving the stability and safety of the overall structure. During the erection of the steel columns, for the steel columns on the column net, they are directly rooted on the first-floor foundation beams. For the steel columns not on the column net, another foundation is used. This design not only takes into account the stability of the foundation, but also simplifies the construction process on the basis of ensuring the support strength and stability of the steel columns.The present invention aims to solve the problems of long construction period and low efficiency in the construction method of adding stairs in traditional reinforced concrete frame structures, and proposes a new construction method. The method realizes efficient and flexible transformation and reinforcement of existing large space frame structure buildings through precise structural analysis and reinforcement design to meet the functional requirements after transformation. The technical scheme of the present invention is mainly based on the design concept of prefabricated assembled stairs. Specifically, the steel beams, steel platform plates and other components of the stairs are prefabricated in the factory, and then installed on site using hoisting equipment. This prefabricated assembly method has simple material connection structure, simple construction process, high construction quality reliability, significantly reduces the amount of wet work on site, and greatly reduces the construction links on site, reduces the construction difficulty and cost, and is suitable for adding steel beams and composite structural beam-slab systems on existing reinforced concrete frame beams. At the same time, the assembled steel structure staircase has the advantages of flexible layout, position adjustment according to actual needs, short construction period, etc., which greatly improves the construction efficiency and shortens the overall construction period, providing an effective solution for the transformation and reinforcement of large space frame structure buildings.

[0013] The present invention realizes the factory-based, standardized and prefabricated construction of stairs by adopting the newly added operations of assembled steel structure stairs and factory prefabricated component assembled stairs, thereby improving the construction efficiency. At the same time, the use of prefabricated components reduces the on-site processing links, shortens the construction period, and effectively reduces the construction cost, providing an efficient, flexible and safe construction solution for the field of building engineering reinforcement and transformation. The method has a simple implementation process, a safe construction process, high construction efficiency, and a flexible construction method. It is suitable for a variety of building function transformation needs, not only for the transformation and reinforcement projects of existing large space frame structure buildings, but also for the staircase construction in new buildings. It has a wide range of application prospects, and at the same time improves the construction efficiency, shortens the overall construction period, and reduces the construction cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a plan view of the building after the prefabricated staircase is added in the present invention; Figure 2 It is a top view of the building after the assembled staircase is added in the present invention; Figure 3 It is a structural schematic diagram of the existing concrete beam after reinforcement in the present invention; Figure 4 yes Figure 3 Schematic cross-section diagram; Figure 5 It is a schematic diagram of the assembly of the steel staircase and the concrete foundation in the present invention; Figure 6 It is a schematic diagram of the assembly of the steel column and the new steel beam in the present invention; Figure 7It is a schematic diagram of the assembly of the steel ladder beam and the steel beam in the present invention.

[0015] In the figure: 1. steel column, 2. new steel beam, 3. steel stairs, 4. steel platform plate, 5. concrete foundation, 6. connecting plate one, 7. inverted cone chemical anchor, 8. anchor plate one, 9. existing concrete beam, 10. concrete floor, 11. long screw, 12. pad, 13. pad, 14. L-shaped angle steel, 15. locking nut, 16. reinforced steel beam, 17. anchor plate two, 18. connecting plate two, 19. high-strength bolt one, 20. existing concrete column. DETAILED DESCRIPTION

[0016] The present invention will be further described below in conjunction with the accompanying drawings.

[0017] like Figures 1 to 7 As shown, the present invention provides a construction method for a newly added assembled staircase in a reinforced concrete frame structure, comprising the following steps: Step 1: Site survey and factory prefabrication; S11: Conducting on-site survey according to the functional requirements of the building and the actual conditions of the building, and determining the area to be demolished on the concrete floor 10; S12: Combined with the on-site survey, the force analysis and calculation of the original reinforced concrete frame structure is carried out, and the reinforcement and reinforcement scheme of the local beams and columns outside the area to be demolished is determined based on the force analysis and calculation results to ensure that the installation process of the new staircase will not cause adverse effects on the original structure; based on the reinforcement and reinforcement scheme, the size of the reinforced steel beam 16, the size of the L-shaped angle steel 14, the size of the anchor plate 8, and the size of the pad 13 required for the reinforcement of the existing concrete beam 9 are determined; at the same time, based on the force analysis and calculation results, the size, structure, weight, bearing strength and installation position of the newly added steel staircase 3 are determined, the size, structure, weight, bearing strength and installation position of the steel platform plate 4 are determined, the size and bearing strength of the new steel beam 2 are determined, and the size and bearing strength of the steel column 1 are determined; S13: Prefabricate the reinforced steel beam 16, L-shaped angle steel 14, anchor plate 8, pad 13, steel staircase 3, steel column 1, and steel platform plate 4 in the factory, wherein the reinforced steel beam 16 is made of I-beam, and a pair of L-shaped angle steels 14 are connected to both ends of the reinforced steel beam 16, and the transverse sections of the pair of L-shaped angle steels 14 are relatively distributed on both sides of the web of the end of the reinforced steel beam 16. Each pair of L-shaped angle steels 14 and the reinforced steel beam 16 are fixedly connected to each other by a plurality of high-strength bolts 19 penetrating the transverse sections of the two L-shaped angle steels 14 and the web of the end of the reinforced steel beam 16. At the same time, a plurality of through holes A are opened on the longitudinal sections of the pair of L-shaped angle steels 14, and a plurality of through holes B are opened on the anchor plate 8; Step 2: Strengthen the original local beams and columns according to the reinforcement and reinforcement plan; The reinforcement process of the existing concrete beam 9 at the edge of the area to be demolished is as follows: S21: Drilling a plurality of screw mounting holes in the reinforcement area on the existing concrete beam 9 in the width direction; S22: Two anchor plates 8 and two reinforced steel beams 16 are sequentially arranged on both sides of the reinforcement area of ​​the existing concrete beam 9, and two pads 13 are arranged on the upper wing plates of the two reinforced steel beams 16 and the bottom surface of the concrete floor slab 10, and then a plurality of long screws 11 are passed through the plurality of screw installation holes, and the two ends of the screws are sequentially passed outward through the plurality of through holes B on the two anchor plates 8 and the plurality of through holes A on the longitudinal sections of the two pairs of L-shaped angle steels 14, and then, the two ends of each long screw 11 are connected from the inside to the outside. Two pads 12 and two sets of locking nuts 15 are sequentially installed, and two pairs of L-shaped angle steels 14 are locked on both sides of the reinforcement area of ​​the existing concrete beam 9 by using the locking nuts 15, so as to fix the ends of the two reinforcement steel beams 16 that are close to each other to the two sides of the existing concrete beam 9; finally, for the ends of the two reinforcement steel beams 16 that are far away from each other, multiple chemical anchor bolts that pass through the longitudinal sections of the pair of L-shaped angle steels 14 are used to fix them to the concrete columns or concrete beams at the opposite ends of the existing concrete beam 9; As a preferred embodiment, after the connection, a quality inspection is required to ensure the firmness of the connection and at the same time, to ensure that there are no defects in the reinforcement scheme.

[0018] As a preference, the long screw 11 is a high-strength full-thread screw.

[0019] Step 3: Demolition of part of the existing concrete floor 10; Demolition work is performed on the area to be demolished on the concrete floor 10, and a hole space is formed in the concrete floor 10; Step 4: Add a steel platform plate 4; S41: According to the determined construction position of the steel platform plate 4, four steel columns 1 are erected at the four corners of the corresponding steel platform plate 4; during the erection process of the steel columns 1, for the steel columns 1 in the first-floor building space, when the steel columns 1 are located on the column net, they are directly rooted on the first-floor foundation tension beam during the erection process, and when the steel columns 1 are not on the column net, another foundation is made during the erection process, and the foundation adopts small-diameter bored piles, and steel pipes are inserted inside to replace steel bars, and then cement mortar is poured into the steel pipes so that the bearing layer at the pile end is coarse sand. At the same time, the pile side post-grouting technology is used to improve the compressive bearing capacity of the foundation; for the steel columns 1 in the non-first-floor building space, professional hoisting equipment is used to hoist the steel columns 1 to the upper building space, and the steel columns 1 are erected on the existing concrete beams 9 or reinforced steel beams 16, and it is ensured that the steel columns 1 are firmly connected to the steel bars in the concrete beams 9 or the reinforced steel beams 16; S42: Use professional lifting equipment to lift the four new steel beams 2 to the required installation height, and arrange the four new steel beams 2 in a U-shape at the construction position of the steel platform plate 4, and then fix the two ends of each new steel beam 2 to the two adjacent steel columns 1 respectively; as a preferred method, the new steel beams 2 and the steel columns can be connected by welding, or by high-strength screws.

[0020] S43: Fix the steel platform plate 4 between the four new steel beams 2; Step 5: Add steel stairs 3; For the first section of steel stairs 3 in the first floor building space, an anchor plate 2 17 is arranged at the bottom end of the first section of steel stairs 3, and the bottom end of the steel ladder beam of the first section of steel stairs 3 is fixedly connected to the anchor plate 2 17 by using the connecting plate 1 6, and then the anchor plate 2 17 is anchored to the surface of the concrete foundation 5 by using the inverted cone chemical anchor bolt 7, and then the top end of the steel ladder beam of the first section of steel stairs 3 is fixedly connected to the new steel beam 2 at the location of the steel platform plate 4 by using the connecting plate 2 18; For the remaining steel stairs 3, they are installed section by section from bottom to top. During the installation process, professional lifting equipment is used to lift the steel stairs 3 through the hole space to the corresponding building space on the upper floor, and the corresponding connection method is selected according to the position of the end of the steel stairs 3. When the end position of the steel staircase 3 corresponds to the steel platform plate 4, the steel ladder beam at the end of the steel staircase 3 is fixedly connected to the new steel beam 2 at the position of the steel platform plate 4 by using the second connecting plate 18. When the end position of the steel staircase 3 corresponds to the edge of the hole space in the original reinforced concrete frame, the steel ladder beam at the end of the steel staircase 3 is fixedly connected to the reinforced steel beam 16 at the corresponding position by using the third connecting plate.

[0021] As a preferred embodiment, in order to ensure the stability and safety of the steel staircase 3, special reinforcement treatment is performed on the connection nodes, such as increasing welding points or increasing the number of high-strength bolts.

[0022] As a preferred embodiment, in step 1 S13, the steel column 1 and the new steel beam 2 are both made of I-beams.

[0023] In order to ensure the bearing capacity and durability so as to meet the strength and stability requirements of the newly added structural system, in step 1 S13, the new steel beam 2, the reinforced steel beam 16 and the steel column 1 are all made of high-strength steel.

[0024] Preferably, in step 2 S22, the thickness of the cushion block 12 is greater than 6 mm, and more preferably, the thickness is not greater than 2 cm.

[0025] As a preferred embodiment, in step 2 S22, when installing the anchor plate 8, ensure that the upper edge of the anchor plate 8 is flush with the lower end surface of the concrete floor 10, and at the same time, ensure that the lower end edge of the anchor plate 8 is flush with the lower end surface of the existing concrete beam 9.

[0026] As a preferred option, in step three, during the demolition process, use professional equipment to accurately cut out parts of the concrete floor slab, and strictly control the construction quality and safety to avoid unnecessary damage to the original building structure. At the same time, take noise reduction measures to reduce the impact on the surrounding environment and residents.

[0027] In order to significantly improve the connection strength between the long screw and the existing concrete beam and ensure that the subsequently installed reinforced steel beam can be stably and reliably connected to the existing concrete beam, in step 2 S22, high-strength grouting material or adhesive is poured into the gap between the long screw 11 and the screw mounting hole.

[0028] In order to effectively improve the bearing strength of the existing concrete column, in step 2, the existing concrete column 20 is reinforced by adding steel bars or pasting steel plates or using carbon fiber composite materials.

[0029] In the present invention, before construction, the original reinforced concrete frame structure is first subjected to force analysis and calculation in combination with the on-site survey, so that the bearing capacity and weak links of the original reinforced concrete frame structure can be determined, and then the reinforcement and reinforcement scheme can be obtained in a targeted manner. At the same time, the position of the newly added steel staircase can be reasonably determined, ensuring the stability and safety of the original building structure after the newly added steel staircase. Before opening the hole space, the original reinforced concrete frame structure is first reinforced, so that it can be ensured that the opening of the hole space and the addition of the steel staircase will not cause adverse effects on the original building structure. In the process of reinforcing the existing concrete beam, two reinforced steel beams are added on both sides of the existing concrete beam, and the two reinforced steel beams are firmly connected to the two sides of the existing concrete beam by using multiple long screws, one anchor plate, two pairs of L-shaped angle steels and multiple sets of locking nuts, effectively connecting the two reinforced steel beams added later to the existing concrete beam stably into an integral structure, so that the force of the overall structure can be more reasonable, and the force requirements and stability requirements of the overall structure can be met under the loss of a certain strength of the original concrete beam. At the same time, the newly added reinforced steel beams greatly improve the bearing capacity and stability of local beams and columns outside the area to be demolished. This reinforcement method solves the problem that the existing connection method cannot achieve stable connection between the existing reinforced concrete beams and the newly added reinforced steel beams. While meeting the needs of the reinforcement function, it also ensures the strength and rigidity of the existing reinforced concrete beams. At the same time, this reinforcement method provides an effective solution for the integral connection of the reinforced steel beams on both sides and the coordinated force of the reinforced steel beams and the concrete floor slabs, ensuring the integrity and reliability of the reinforced structure. By opening the hole space, it is easy to lift the prefabricated steel stairs, steel platform plates, reinforced steel beams, steel columns, new steel beams and other components required for the renovation through the hole space to the superstructure space, improving the convenience during the construction process. New steel beams, steel platform plates, steel stairs, reinforced steel beams, L-shaped angle steels, anchor plates, pads, and steel columns are all prefabricated in the factory, then transported to the construction site, and then precisely assembled according to the design requirements to form a complete reinforced structure and steel staircase structure, effectively improving the construction efficiency and reducing the impact of the construction process on the site environment. Using multiple high-strength steel bolts to fix a pair of L-shaped angle steels on both sides of the web at the end of the reinforced steel beam not only makes the installation and disassembly process more convenient, but also ensures the firmness and reliability of the connection, effectively improving the stability and safety of the overall structure. During the erection of the steel columns, for the steel columns on the column net, they are directly rooted on the first-floor foundation beams. For the steel columns not on the column net, another foundation is used. This design not only takes into account the stability of the foundation, but also simplifies the construction process on the basis of ensuring the support strength and stability of the steel columns.The present invention aims to solve the problems of long construction period and low efficiency in the construction method of adding stairs in traditional reinforced concrete frame structures, and proposes a new construction method. The method realizes efficient and flexible transformation and reinforcement of existing large space frame structure buildings through precise structural analysis and reinforcement design to meet the functional requirements after transformation. The technical scheme of the present invention is mainly based on the design concept of prefabricated assembled stairs. Specifically, the steel beams, steel platform plates and other components of the stairs are prefabricated in the factory, and then installed on site using hoisting equipment. This prefabricated assembly method has simple material connection structure, simple construction process, high construction quality reliability, significantly reduces the amount of wet work on site, and greatly reduces the construction links on site, reduces the construction difficulty and cost, and is suitable for adding steel beams and composite structural beam-slab systems on existing reinforced concrete frame beams. At the same time, the assembled steel structure staircase has the advantages of flexible layout, position adjustment according to actual needs, short construction period, etc., which greatly improves the construction efficiency and shortens the overall construction period, providing an effective solution for the transformation and reinforcement of large space frame structure buildings.

[0030] The present invention realizes the factory-based, standardized and prefabricated construction of stairs by adopting the newly added operations of assembled steel structure stairs and factory prefabricated component assembled stairs, thereby improving the construction efficiency. At the same time, the use of prefabricated components reduces the on-site processing links, shortens the construction period, and effectively reduces the construction cost, providing an efficient, flexible and safe construction solution for the field of building engineering reinforcement and transformation. The method has a simple implementation process, a safe construction process, high construction efficiency, and a flexible construction method. It is suitable for a variety of building function transformation needs, not only for the transformation and reinforcement projects of existing large space frame structure buildings, but also for the staircase construction in new buildings. It has a wide range of application prospects, and at the same time improves the construction efficiency, shortens the overall construction period, and reduces the construction cost.

Claims

1. A construction method for newly added assembled stairs in a reinforced concrete frame structure, characterized in that: The following steps are involved: Step 1: Site survey and factory prefabrication; S11: Conducting on-site survey according to the functional requirements of the building and the actual conditions of the building, and determining the area on the concrete floor (10) to be demolished; S12: Based on the on-site survey, a force analysis and calculation is performed on the original reinforced concrete frame structure, and a reinforcement and strengthening plan for the local beams and columns outside the area to be demolished is determined based on the force analysis and calculation results to ensure that the installation process of the new staircase will not cause adverse effects on the original structure; based on the reinforcement and strengthening plan, the size of the reinforcement steel beam (16), the size of the L-shaped angle steel (14), the size of the anchor plate (8), and the size of the pad (13) required for reinforcing the existing concrete beam (9) are determined; at the same time, based on the force analysis and calculation results, the size, structure, weight, bearing strength and installation position of the new steel staircase (3) are determined, the size, structure, weight, bearing strength and installation position of the steel platform plate (4) are determined, the size and bearing strength of the new steel beam (2) are determined, and the size and bearing strength of the steel column (1) are determined; S13: Prefabricate in a factory a reinforced steel beam (16), an L-shaped angle steel (14), an anchor plate (8), a pad (13), a steel staircase (3), a steel column (1), and a steel platform plate (4), wherein the reinforced steel beam (16) is made of an I-beam, and a pair of L-shaped angle steels (14) are connected to each end of the reinforced steel beam (16), the transverse sections of the pair of L-shaped angle steels (14) are relatively distributed on both sides of the web plate at the end of the reinforced steel beam (16), and each pair of L-shaped angle steels (14) and the reinforced steel beam (16) are fixedly connected to each other by a plurality of high-strength bolts (19) that penetrate the transverse sections of the two L-shaped angle steels (14) and the web plate at the end of the reinforced steel beam (16). At the same time, a plurality of through holes A are opened on the longitudinal sections of the pair of L-shaped angle steels (14), and a plurality of through holes B are opened on the anchor plate (8); Step 2: Strengthen the original local beams and columns according to the reinforcement and reinforcement plan; The reinforcement process for the existing concrete beams (9) at the edge of the area to be demolished is as follows: S21: drilling a plurality of screw mounting holes extending through the width direction in the reinforcement area of ​​the existing concrete beam (9); S22: Two anchor plates (8) and two reinforced steel beams (16) are sequentially arranged on both sides of the reinforcement area of ​​the existing concrete beam (9), and two pads (13) are arranged on the upper wing plates of the two reinforced steel beams (16) and the bottom surface of the concrete floor slab (10). Then, a plurality of long screws (11) are passed through the plurality of screw mounting holes, and the two ends of the screws are sequentially passed outward through the plurality of through holes B on the two anchor plates (8) and the plurality of through holes A on the longitudinal sections of the two pairs of L-shaped angle steels (14). Then, the two ends of each long screw (11) are screwed from the inside to the outside. Two pads (12) and two sets of locking nuts (15) are sequentially installed, and two pairs of L-shaped angle steels (14) are locked on both sides of the reinforcement area of ​​the existing concrete beam (9) using the locking nuts (15) to fix the ends of the two reinforced steel beams (16) that are close to each other to the two sides of the existing concrete beam (9); finally, the ends of the two reinforced steel beams (16) that are far away from each other are fixedly connected to the concrete columns or concrete beams at the opposite ends of the existing concrete beam (9) using a plurality of chemical anchor bolts that pass through the longitudinal sections of the pair of L-shaped angle steels (14); Step 3: demolition of part of the existing concrete floor slab (10); Performing demolition work on the area to be demolished on the concrete floor slab (10), and forming a hole space in the concrete floor slab (10); Step 4: Add a steel platform plate (4); S41: According to the determined steel platform plate (4) erection position, four steel columns (1) are erected at the four corners of the corresponding steel platform plate (4); during the erection of the steel columns (1), for the steel columns (1) in the first-floor building space, when the steel columns (1) are located on the column net, they are directly rooted on the first-floor foundation tie beam during the erection process; when the steel columns (1) are not on the column net, another foundation is made during the erection process, and the foundation adopts small-diameter bored piles, and steel pipes are inserted to replace steel bars, and cement mortar is poured into the steel pipes so that the bearing layer at the pile end is coarse sand. At the same time, the pile side post-grouting technology is used to improve the compressive bearing capacity of the foundation; for the steel columns (1) in the non-first-floor building space, the steel columns (1) are hoisted to the upper building space by professional hoisting equipment, and the steel columns (1) are erected on the existing concrete beams (9) or reinforced steel beams (16), and it is ensured that the steel columns (1) are firmly connected to the steel bars in the concrete beams (9) or the reinforced steel beams (16); S42: Using professional lifting equipment to lift the four new steel beams (2) to the required installation height, and arrange the four new steel beams (2) in a U-shaped manner at the construction position of the steel platform plate (4), and then fix the two ends of each new steel beam (2) to the two adjacent steel columns (1) respectively; S43: Fixing the steel platform plate (4) between the four new steel beams (2); Step 5: Add steel stairs (3); For the first section of steel stairs (3) in the first floor building space, an anchor plate 2 (17) is arranged at the bottom end of the first section of steel stairs (3), and the bottom end of the steel ladder beam of the first section of steel stairs (3) is fixedly connected to the anchor plate 2 (17) by using the connecting plate 1 (6), and then the anchor plate 2 (17) is anchored to the surface of the concrete foundation (5) by using the inverted cone chemical anchor bolt (7), and then the top end of the steel ladder beam of the first section of steel stairs (3) is fixedly connected to the new steel beam (2) at the location of the steel platform plate (4) by using the connecting plate 2 (18); The remaining steel stairs (3) are installed section by section from bottom to top. During the installation process, the steel stairs (3) are lifted through the hole space to the corresponding building space on the upper floor using professional lifting equipment, and the corresponding connection method is selected according to the position of the end of the steel stairs (3). When the end position of the steel stairs (3) corresponds to the steel platform plate (4), the steel ladder beam at the end of the steel stairs (3) is fixedly connected to the new steel beam (2) at the location of the steel platform plate (4) using the second connection plate (18). When the end position of the steel stairs (3) corresponds to the edge of the hole space in the original reinforced concrete frame, the steel ladder beam at the end of the steel stairs (3) is fixedly connected to the reinforced steel beam (16) at the corresponding position using the third connection plate.

2. The construction method of a newly added assembled staircase in a reinforced concrete frame structure according to claim 1, characterized in that: In step 1 S13, the steel column (1) and the new steel beam (2) are both made of I-beams.

3. The construction method of a newly added assembled staircase in a reinforced concrete frame structure according to claim 2 is characterized in that: In step 1 S13, the new steel beam (2), the reinforced steel beam (16) and the steel column (1) are all made of high-strength steel.

4. The construction method of a newly added assembled staircase in a reinforced concrete frame structure according to claim 3 is characterized in that: In step 2 S22, the thickness of the cushion block (12) is greater than 6 mm.

5. The construction method of a newly added assembled staircase in a reinforced concrete frame structure according to claim 4 is characterized in that: In step 2 S22, when installing the anchor plate 1 (8), ensure that the upper edge of the anchor plate 1 (8) is flush with the lower end surface of the concrete floor slab (10), and at the same time, ensure that the lower edge of the anchor plate 1 (8) is flush with the lower end surface of the existing concrete beam (9).

6. The construction method of a newly added assembled staircase in a reinforced concrete frame structure according to claim 5, characterized in that: In step three, during the demolition operation, professional equipment is used to accurately remove part of the concrete floor slab (10), and the construction quality and safety are strictly controlled to avoid unnecessary damage to the original building structure. At the same time, noise reduction measures are taken to reduce the impact on the surrounding environment and residents.

7. The construction method of a newly added assembled staircase in a reinforced concrete frame structure according to claim 6, characterized in that: In step 2 S22, high-strength grouting material or adhesive is poured into the gap between the long screw (11) and the screw mounting hole.

8. The construction method of a newly added assembled staircase in a reinforced concrete frame structure according to claim 7, characterized in that: In step 2, the existing concrete column (20) is reinforced by adding steel bars or bonding steel plates or using carbon fiber composite materials.

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