Installation and construction method of gymnasium atrium steel structure spiral staircase

Abstract

The invention belongs to the technical field of building construction, and particularly relates to an installation and construction method of a gymnasium atrium steel structure spiral staircase, and the gymnasium atrium steel structure spiral staircase can smoothly enter and exit a gymnasium atrium through a gymnasium doorway by selecting a small crane. According to the construction method, the stair body is divided into the multiple stair sections meeting the hoisting requirement of the small crane, and the multiple stair sections are hoisted in the courtyard of the stadium through the small crane so that hoisting and splicing of the stair sections in the stadium can be completed. The problem of limitation of a stadium structure on stair hoisting is solved, stadium wall bodies do not need to be disassembled and changed, and the operation process is simplified; the assembling and welding of each stair section of the stair are controlled in a hoisting and temporary supporting manner, so that not only is the stability of each stair section during the assembling and welding operation ensured, but also the deformation of the stair sections of the steel structure under the action of gravity in the welding process is reduced, the assembling and welding precision of the stair sections is improved, and the mounting progress of the whole stair is ensured.

Description

Technical Field

[0001] This invention belongs to the field of building construction technology, specifically relating to a method for installing a steel structure spiral staircase in a stadium atrium. Background Technology

[0002] Steel spiral staircases are widely used in public buildings such as outdoor sky bridges, sports venues, and libraries due to their aesthetic appeal and high space utilization. Generally, steel spiral staircases are welded and assembled as a whole on-site, then hoisted directly to the predetermined position using lifting equipment and welded to the main structure such as floor slabs or bridges. Finally, steel locks are used for layered tensioning. This construction method is only suitable for installing steel spiral staircases when construction space is not limited. However, for the construction of multi-story steel structure staircases with large outer diameters and heights in the atriums of large stadiums, where the surrounding walls, floors, ceilings, and other main structures are already completed, and the entrance width and height are relatively small, the above method can still be used for steel staircases with relatively small overall weight. However, when construction space is limited and the overall weight and dimensions of the staircase are large, the above common method cannot be used to complete the overall hoisting of the steel structure staircase.

[0003] Currently, a large stadium's atrium features a four-story steel spiral staircase. This staircase has an outer diameter exceeding 10 meters, a height exceeding 20 meters, and a total weight exceeding 60 tons. Its overall size and weight are substantial. The staircase is located on one side of the atrium, and its distance from the wall is limited, making it inaccessible to cranes. Therefore, the operating space is restricted, and cranes can only perform lifting operations on the side of the staircase closest to the center of the atrium. Furthermore, the largest door in the stadium is less than 6 meters wide and less than 4 meters high. The lifting equipment required to hoist the entire steel spiral staircase is too large and would be difficult to pass through the completed doors into the stadium. On-site attempts were made to create a sufficiently large opening in one wall to allow large hoisting equipment to enter the venue and hoist the entire spiral staircase. However, due to the large total weight and size of the steel spiral staircase to be installed, there were not only issues such as center of gravity shift and excessive spatial positioning deviation during the overall hoisting and welding, making it difficult to guarantee the installation accuracy and construction safety of the staircase, but also posing a risk of collapsing the floor slab. After the staircase was installed and the large hoisting equipment was moved out, the reserved opening had to be sealed, making the construction process complicated. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a construction method for installing a steel structure spiral staircase in the atrium of a venue, thereby improving the installation accuracy of the staircase and enhancing construction safety and reliability.

[0005] The technical solution adopted by this invention to solve this technical problem is: a method for installing a steel structure spiral staircase in a stadium atrium, including the following steps.

[0006] S1. Construction preparation work, including:

[0007] S1-a. Select a crane that can enter the atrium of the venue based on the size of the venue entrance;

[0008] S1-b: Divide the main body of the staircase into multiple platform stair sections and spiral stair sections. The weight of the spiral stair section and the platform stair section are both within the safe load of the crane selected in step S1-a. The platform stair section at the bottom is called the first platform stair section, and the spiral stair section at the bottom is called the first spiral stair section.

[0009] S1-c, Level the ground in the atrium of the venue and draw the outline of the stairs on the ground;

[0010] S1-d, manufacture a first bracket for supporting the lower end of the first platform stair section, a second bracket for supporting the lower end of the first spiral stair section, and a third bracket for supporting the upper end of the first spiral stair section;

[0011] S2. Lifting operations include:

[0012] S2-a. Erect the first and second supports on the ground of the venue according to the outline of the first platform ladder section;

[0013] After the crane enters the atrium of the venue and is in place, the crane is started to lift the first platform stair section to the preset position on the upper side of the first and second supports, and weld the platform end of the first platform stair section to the main steel beam of the first support and the second floor slab of the venue, and weld the other end of the first platform stair section to the second support.

[0014] S2-b, Install the connecting beam assembly so that its upper end is on the top surface of the second support, and then assemble and weld the upper end of the connecting beam assembly to the end of the first platform ladder that is away from its upper platform ladder. The lower end of the connecting beam assembly has a support leg fixed to the venue floor.

[0015] S2-c, Erect a third support on the ground of the venue, hoist the first spiral stair section and weld its lower end to the end face of the platform stair section of the first platform stair section, and weld the upper end of the first spiral stair section to the top surface of the third support;

[0016] S2-d. Temporary supports are welded on the ladder surface directly below the spiral ladder section and platform ladder section to be hoisted. The remaining spiral ladder sections and platform ladder sections to be hoisted are hoisted and assembled and welded to each other in the order of distribution from bottom to top. The platform ladder sections are all welded to the main steel beams on the corresponding floor slab.

[0017] When the connecting beam assembly is directly below the spiral stair section to be hoisted, the temporary support is welded to the third support.

[0018] When the height difference between the top of the process staircase and the ceiling of the venue directly above it is within 6m during the hoisting process, the remaining platform staircases and spiral staircases are hoisted in the order of distribution from top to bottom.

[0019] S2-e, the crane was driven out of the venue, and then the bottom extension frame section was installed;

[0020] S3. Install multiple cables on the ceiling of the venue, connect the lower end of the cables to each spiral stair section and platform stair section for layered tensioning, and tension the cables symmetrically on the same spiral stair section or platform stair section.

[0021] After the layered tensioning is completed, the first support, second support, third support, and temporary support are removed.

[0022] Furthermore, the crane is a truck crane, and a single load-bearing steel plate is laid on the ground of the venue below the outriggers of the truck crane.

[0023] Furthermore, step S1 also includes step S1-e, which is carried out after step S1-d is completed;

[0024] Step S1-e includes: setting and marking at least 4 lifting points on the platform stair section and the spiral stair section respectively, the shape formed by the sequential connection of the at least 4 lifting points is a rectangular structure, lifting lugs are welded at the ends of the platform stair section and the spiral stair section, and the center line of gravity of the platform stair section and the spiral stair section is marked.

[0025] Furthermore, the first support includes at least four first columns and a first crossbar perpendicular to the first columns, with the upper ends of two adjacent first columns connected by the first crossbar; the top surface height of the first crossbar is the same as the bottom surface installation height of the platform section on the first platform staircase; the second support is a portal frame structure and its top surface is at the same height as the bottom surface of the end of the first platform staircase away from its platform section.

[0026] It also includes at least two connecting rods, through which the first column and the second bracket are connected; the top surface of the connecting rod is flush with the top surface of the second bracket.

[0027] Furthermore, step S1-b is carried out after the crane selection in step S1-a is confirmed, and steps S1-c and S1-d are carried out simultaneously with step S1-a or S1-b.

[0028] Furthermore, the second support includes two second columns distributed on both sides of the first platform stair section and a second crossbar connecting the two second columns; the bottom surface of the first platform stair section away from its platform section end and the bottom surface of the upper end of the connecting beam assembly are both welded to the top surface of the second crossbar.

[0029] Furthermore, before step S2-b begins, a trial lifting operation must be performed on the platform ladder section and the spiral ladder section;

[0030] The trial lifting operation includes: lifting the ladder section to 200mm above the ground and letting it stand for 10 minutes to observe the settlement of the crane outriggers. Subsequent lifting operations can only be carried out if the outrigger settlement is within 5mm and the angle between the sling and the horizontal plane is within 60°-90°. During the trial lifting, a force gauge should also be used to monitor and compare the force difference of each sling. If the center of gravity offset of the ladder section is greater than 100mm, a counterweight should be added to the raised end to make the horizontal deviation of the ladder section within 2mm / m.

[0031] Furthermore, before hoisting the spiral stair section adjacent to the platform stair section in step S2-d, the platform stair section located above and adjacent to it is first hoisted and installed.

[0032] Furthermore, after step S3-b tensions the staircase to 100% of the design value in each layer, the top-floor staircase needs to be additionally tensioned to 102% of the design value.

[0033] Compared with the prior art, the beneficial effects of the present invention are as follows: It provides a construction method for installing a steel spiral staircase in a stadium atrium. By using a small crane, it can smoothly enter and exit the stadium atrium through the stadium entrance. The staircase main body is divided into multiple stair sections that meet the lifting requirements of the small crane. These sections are then lifted and assembled within the stadium atrium using the small crane. This construction method allows installation to be carried out after the main stadium structure is completed, overcoming the limitations imposed by the stadium structure on staircase lifting. It eliminates the need to demolish or alter stadium walls, simplifying the work process. Furthermore, the use of lifting and temporary supports to control the assembly and welding of each stair section not only ensures the stability of each section during assembly and welding but also reduces deformation of the steel structure sections under gravity during welding, improving the accuracy of stair section assembly and welding, and ensuring the overall installation progress of the staircase. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of the steel spiral staircase installed inside the venue in this invention;

[0035] Figure 2 This is an axonometric view of the main structure of the steel spiral staircase of the present invention after hoisting.

[0036] Figure 3 This is a schematic diagram of the assembly structure of the first support, the second support, and the first portal frame in this invention;

[0037] Figure 4 This is a schematic diagram of the structure of the third and fourth supports in this invention;

[0038] Figure 5This is a schematic diagram of the structure of the second platform support in this invention;

[0039] Figure 6 This is a schematic diagram of the connection structure between the columns of each support and the venue floor in this invention;

[0040] Figures 7a-7j This is a schematic diagram of the hoisting process in step S2 of the present invention;

[0041] Reference numerals: 1-First support; 11-First column; 12-First crossbar; 123-Anchor plate; 2-Second support; 21-Connecting rod; 22-Second column; 23-Second crossbar; 3-Third support; 31-Third column; 32-Third crossbar; 4-Fourth support; 51-First portal frame support; 52-Second portal frame support; 61-Second platform support; 611-Fourth column; 612-Fourth crossbar; 62 - Third platform support; 71- First spiral staircase; 72- Second spiral staircase; 73- Third spiral staircase; 74- Fourth spiral staircase; 80- Lifting lug; 81- First platform staircase; 82- Second platform staircase; 83- Third platform staircase; 90- Cable; 91- Bottom extension frame section; 92- Connecting beam assembly; 93- Second floor slab; 94- Third floor slab; 95- Fourth floor slab; 98- Crane; 99- Stadium ceiling. Detailed Implementation

[0042] The present invention will be further described below with reference to the accompanying drawings and embodiments. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention. For ease of explanation, the term "staircase" in the present invention refers to a pre-installed steel structure spiral staircase with a height of 28m. Figures 7a-7j The arrangement is based on the sequence of hoisting the ladder sections.

[0043] Reference Figure 1 -7. A construction method for installing a steel spiral staircase in the atrium of a stadium, including the following steps.

[0044] S1. Construction preparation work, including:

[0045] S1-a. Select a crane that can enter the atrium of the venue based on the size of the venue entrance;

[0046] S1-b: Divide the main body of the staircase into multiple platform stair sections and spiral stair sections. The weight of the spiral stair section and the platform stair section are both within the safe load of the crane selected in step S1-a. The platform stair section at the bottom is called the first platform stair section 81, and the spiral stair section at the bottom is called the first spiral stair section 71.

[0047] S1-c, Level the ground in the atrium of the venue and draw the outline of the stairs on the ground;

[0048] S1-d, manufacture a first support 1 for supporting the lower end of the first platform stair section, a second support 2 for supporting the lower end of the first spiral stair section 71, and a third support 3 for supporting the upper end of the first spiral stair section 71;

[0049] S2. Lifting operations include:

[0050] S2-a. Erect the first support 1 and the second support 2 on the ground of the venue according to the outline of the first platform ladder section;

[0051] After the crane 98 enters the atrium of the venue and is in place, the crane 98 is started to lift the first platform stair section 81 to the preset position on the upper side of the first support 1 and the second support 2, and weld the platform end of the first platform stair section 81 to the main steel beam of the first support 1 and the second floor slab 93 of the venue, and weld the other end of the first platform stair section 81 to the second support 2.

[0052] S2-b, Install the connecting beam assembly 92 so that its upper end is located on the top surface of the second bracket 2, and then assemble and weld the upper end of the connecting beam assembly 92 to the end of the first platform ladder section 81 away from its upper platform ladder section. The lower end of the connecting beam assembly 92 has a support leg fixed to the venue floor.

[0053] S2-c, Erect the third support 3 on the ground of the venue, hoist the first spiral stair section 71 and weld its lower end to the end face of the platform stair section 81, and weld the upper end of the first spiral stair section 71 to the top surface of the third support 3.

[0054] S2-d. Temporary supports are welded on the ladder surface directly below the spiral ladder section and platform ladder section to be hoisted. The remaining spiral ladder sections and platform ladder sections to be hoisted are hoisted and assembled and welded to each other in the order of distribution from bottom to top. The platform ladder sections are all welded to the main steel beams on the corresponding floor slab.

[0055] When the connecting beam assembly 92 is directly below the spiral stair section to be hoisted, the temporary support is welded onto the third support 3;

[0056] When the height difference between the top of the process staircase and the ceiling of the venue directly above it is within 6m during the hoisting process, the remaining platform staircases and spiral staircases are hoisted in the order of distribution from top to bottom.

[0057] S2-e and crane 98 were driven out of the venue, and then the bottom extension frame section 91 was installed;

[0058] S3. Install multiple cables 90 on the ceiling 99 of the venue, and connect the lower end of the cables 90 to each spiral stair section and platform stair section for layered tensioning. Cables 90 are symmetrically tensioned in the same spiral stair section or platform stair section.

[0059] After the layered tensioning is completed, remove the first support 1, the second support 2, the third support 3, and the temporary support.

[0060] like Figure 2 As shown, the overall structure of the staircase involved in this invention includes a bottom extension frame section 91 arranged from bottom to top, a connecting beam assembly 92, and a staircase body; the bottom extension frame section 91 is a straight staircase structure arranged at an incline upward, which extends out of the outer ring of the staircase and is erected on the venue floor; the connecting beam assembly 92 is used to connect the bottom extension frame section 91 and the staircase body, which is assembled from steps and crossbeams, and has multiple legs at the bottom.

[0061] Due to the limited size of the venue's main entrance, and to ensure that crane 98 can freely enter and exit the venue's atrium, a smaller rated lifting load is selected for crane 98. Generally, a truck crane with a rated load of 13t is chosen. This type of crane 98 is small in size and can easily enter and exit the venue. The maximum rated load of crane 98 is 13.9 tons. Because of the small size and rated load of crane 98, its boom length is also small, generally only suitable for lifting spiral staircases with a total height of less than 30m. During the lifting process, the load transmitted to the venue floor by crane 98 includes the weight of crane 98 itself and the weight of the lifted object. Concentrating the load at the outriggers of crane 98 can easily damage the venue floor. Preferably, crane 98 is a truck crane; a single load-bearing steel plate is laid on the venue floor below the outriggers of the truck crane. The area of ​​the load-bearing steel plate must be large enough to distribute the weight of the truck crane across a larger area of ​​the venue floor, meeting the floor slab bearing capacity requirements and preventing pressure concentration at the outriggers from causing overload and damage to the venue floor.

[0062] To utilize the small-sized, low-load-rated crane 98 for stair installation, the large-volume, heavy-duty multi-story steel spiral staircase needs to be divided into multiple segments. The segments directly connected to the main steel beams on each floor slab are called platform segments. Platform segments generally include a platform section parallel to the horizontal plane and a segment sloping upwards from the end furthest from the platform section to the end closest to it. The segment connecting two platform segments is called a spiral segment. To ensure the crane 98 can safely and reliably lift and assemble these segments, the weight of a single segment is generally within 80% of the crane 98's rated lifting capacity, and the crane 98's safe load is 80% of its rated lifting capacity. For ease of explanation, as... Figure 2As shown, the lowest platform staircase is called the first platform staircase 81, which connects to the main steel beam on the second-floor slab 93 of the venue. The platform staircase connecting to the main steel beam on the third-floor slab 94 of the venue is called the second platform staircase 82, and so on. The platform staircase connecting to the main steel beam on the Nth floor slab of the venue is called the (N-1)th platform staircase. The lowest spiral staircase is called the first spiral staircase 71, whose lower end connects to the platform segment of the first platform staircase 81. Counting from bottom to top, the second spiral staircase is called the second spiral staircase 72, and so on for the remaining spiral staircases. The number of spiral staircases between two adjacent platform staircases is determined by the total weight of the spiral staircases between them, and they are cut as close as possible to the landing platform between them for easier installation. Generally, BIM software is used to model the entire staircase structure and estimate the weight of each segment before designing and cutting.

[0063] To facilitate subsequent hoisting operations, preferably, step S1 further includes step S1-e, which is performed after step S1-d. Step S1-e includes: setting and marking at least four lifting points on the platform stair section and the spiral stair section respectively. The shape formed by the sequential connection of the at least four lifting points is a rectangular structure. Lifting lugs 80 are welded to the ends of both the platform stair section and the spiral stair section, and the center lines of gravity of the platform stair section and the spiral stair section are marked. The lifting lugs 80 are generally made of 20mm thick steel plate and have lifting through holes for hooking hooks or threading binding ropes. The distance between the lifting point and the end of the stair section is generally 1.2m.

[0064] The venue floor is a smooth concrete formwork structure. To ensure construction safety, step S1-c generally requires roughening and leveling the venue floor, marking the center coordinates of the stairs using a total station, and projecting the outlines of the bottom extension frame section 91, connecting beam assembly 92, platform stair sections, and spiral stair sections onto the ground. In step S1-d, the first support 1, second support 2, and third support 3 are all welded from multiple steel bars and can be configured as a portal frame structure. Preferably, the first support 1 includes at least four first columns 11 and a first crossbar 12 perpendicular to the first columns 11. The upper ends of two adjacent first columns 11 are connected by the first crossbar 12. The top surface height of the first crossbar 12 is the same as the bottom surface installation height of the platform section 81 of the first platform ladder. The second support 2 is a portal frame structure, and its top surface is at the same height as the bottom surface of the end of the first platform ladder section away from its platform section. It also includes at least two connecting rods 21, and the first columns 11 and the second support 2 are connected by the connecting rods 21. The top surface of the connecting rods 21 is flush with the top surface of the second support 2. The first support 1 and the second support 2 are designed as an integrated structure that is interconnected, which facilitates erection and disassembly. The first columns 11, the first crossbars 12, the connecting rods 21, and the rods used to make the portal frame are generally made of steel pipes with a rectangular cross-section. The connecting rods 21 and the first crossbars 12 are welded to the first columns 11, and the connecting rods 21 are welded to the second support 2 of the portal frame structure.

[0065] Step S1 is the construction preparation work. During this process, the cut platform stair sections and spiral stair sections, etc., should be transported to the construction site in advance to facilitate hoisting by the crane 98. Preferably, step S1-b is carried out after the crane 98 selection in step S1-a is confirmed. Steps S1-c and S1-d are carried out simultaneously with steps S1-a or S1-b to save construction time.

[0066] Step 2, the hoisting operation, is a key construction step of this invention. During this hoisting process, a boom lift and a scissor lift are used to assist the crane 98. The first support 1, the second support 2, and the third support 3 are all temporary support structures, which can be cast and connected to the venue ground or fixed to the venue ground by bolts. Preferably, the bottom of the first support 1, the second support 2, and the third support 3 are all welded with anchor plates 123 parallel to the ground. The anchor plates 123 are fixed to the venue ground by expansion bolts, which facilitates the erection and dismantling of the temporary support structures and provides flexibility.

[0067] Preferably, the second support 2 includes two second columns 22 distributed on both sides of the first platform stair section 81 and a second crossbar 23 connecting the two second columns 22; the bottom surface of the first platform stair section 81 at the end away from its platform section and the bottom surface of the upper end of the connecting beam assembly 92 are both welded to the top surface of the second crossbar 23. Considering that the connecting beam assembly 92 is a component structure assembled on site, its structural strength is insufficient to bear the weight of the subsequently assembled spiral stair section or platform stair section. Therefore, the second columns 22 are set on both sides of the connecting beam assembly 92 as the main load-bearing structure, which facilitates the subsequent direct welding of the imaginary support to the top surface of the second columns 22 to support the subsequent stair section and realize the positioning and installation of the subsequent stair section.

[0068] To ensure hoisting safety, specifically, a trial hoisting operation must be performed on the platform and spiral stair sections before step S2-b. This trial hoisting includes: lifting the stair section to 200mm above the ground and holding it for 10 minutes to observe the settlement of the crane outriggers. Subsequent hoisting operations can only proceed if the outrigger settlement is within 5mm and the angle between the slings and the horizontal plane is between 60° and 90°. During the trial hoisting, a force gauge should be used to monitor and compare the force differences of each sling. If the center of gravity offset of the stair section is greater than 100mm, a counterweight should be added to the raised end to ensure the levelness deviation of the stair section is within 2mm / m. Performing a trial hoisting before actual hoisting ensures the stability and safety of subsequent hoisting operations, guarantees construction safety, and ensures the welding accuracy of the stair sections. During hoisting, the high-altitude alignment and connection of the stair sections is generally achieved using a boom lift, with coordinate measurements taken using a total station. The connection between the stair section and the main steel beam of the floor slab, as well as the connection between adjacent stair sections, is achieved through a combination of temporary bolt connections and welding.

[0069] Preferably, before hoisting the spiral stair section adjacent to the platform stair section below it in step S2-d, the platform stair section located above and adjacent to it is hoisted and installed first. For example... Figure 7c-7fAs shown, there are two spiral stair sections between the first platform stair section 81 and the second platform stair section 82. The spiral stair section located on the lower side is the first spiral stair section 71, and the other spiral stair section is the second spiral stair section 72. After the first platform stair section 81 and the first spiral stair section 71 are installed, the second platform bracket 61 is first welded to the top surface of the first platform stair section 81. The height of the support surface of the second platform bracket 61 is flush with the height of the bottom surface of the platform section of the second platform stair section 82. Then, the second platform stair section 82 is hoisted to the designated position and its platform section is welded and fixed to the main steel beam of the third floor slab 94 and the second platform bracket 61. Then, the first portal bracket 51 is welded to the top of the second bracket 2 below the end of the second platform stair section 82 away from the platform section. Finally, the second spiral stair section 72 is hoisted and its upper end is welded and fixed to the second platform stair section 82 and the first portal bracket 51, and the lower end of the second spiral stair section 72 is welded and fixed to the third bracket 3 and the first spiral stair section 71. During this process, the pre-installed second platform stair section 82 is fixedly connected to the main steel beam of the third floor slab 94. It can not only provide a stable connection structure for the adjacent second spiral stair section 72 connected to its lower side, but also be used for positioning and providing a stable connection for the first portal frame 51.

[0070] Because the spiral staircase is located on one side of the stadium's atrium and its distance from the wall is small, the operating space is limited. Crane 98 can only perform hoisting operations on the side of the staircase closest to the center of the atrium. Furthermore, the stadium has a suspended ceiling 99 structure. If the spiral staircase section closest to crane 98 is hoisted and fixed first, it will interfere with the hoisting of the upper spiral staircase section and the platform staircase section. Therefore, in step S2-d, "when the height difference between the top of the process staircase section and the suspended ceiling 99 directly above it is within 6m, the remaining platform staircase section and spiral staircase section are hoisted in a top-down distribution sequence" to achieve the hoisting of the entire staircase within the limited space of the stadium. Taking a four-story stadium as an example... Figure 7h-7jAs shown, after the first spiral stair section 71, the second spiral stair section 72, and the second platform stair section 82 are all hoisted and fixed, the third platform support 62 is first erected on the top surface of the second platform stair section 82, and then the third platform stair section 83 is hoisted above the third platform support 62, and the third platform stair section 83 is welded and fixed to the third platform support 62 and the main steel beam on the fourth floor slab 94 respectively; then, the second portal frame support 52 is welded to the top surface of the second spiral stair section 72 below the end of the third platform stair section 83 away from its platform stair section. The top surface of the second portal frame support 52 is welded and fixed to the third platform stair section 83 and protrudes from the end face of the third platform stair section 83 away from its platform stair section. A fourth spiral stair section is welded on the third support 3. The fourth support 4 is installed at the lower part of the third spiral stair section 74 and the upper part of the third spiral stair section 73. Then, the fourth spiral stair section 74 is hoisted to the top of the fourth support 4 and the second portal frame support 52 and welded to them respectively. The upper end of the fourth spiral stair section 74 is assembled and welded to the lower end of the third platform stair section 83. Finally, the third spiral stair section 72 is hoisted to the top of the fourth support 4. The lower end of the third spiral stair section 72 is assembled and welded to the second platform stair section 82. The upper end of the third spiral stair section 72 is assembled and welded to the lower end of the fourth spiral stair section 74 respectively. The bottom surface of the third spiral stair section 72 is welded to the fourth support 4. At this time, the hoisting of the third platform stair section 83, the fourth spiral stair section 74 and the third platform stair section 73 at the top of the staircase is completed under the limited height space.

[0071] After the main structure of the staircase is hoisted, the bottom extension frame 91 is assembled. The bottom extension frame 91 extends beyond the outer edge of the spiral staircase section and is generally located on the side closer to the center of the stadium atrium. That is, the bottom extension frame 91 is located on the side of the crane 98. Therefore, space can be made for the fixed assembly of the bottom extension frame 91 only after the crane 98 is moved away in step S2-e.

[0072] The first portal frame 51 and the second portal frame 52 mentioned above can be common portal frames. To ensure the stability of the structure, preferably, the columns of the first portal frame 51 and the second portal frame 52 are provided with reinforcing diagonal bars welded to their upper ends, and the reinforcing diagonal bars are arranged inclined upwards; the lower ends of the reinforcing diagonal bars on the first portal frame 51 are welded to the second support 2, and the lower ends of the reinforcing diagonal bars on the second portal frame 52 are welded to the second spiral stair section 72.

[0073] The third support 3 is mainly used to support the upper end of the first spiral stair section 71 and the lower end of the second spiral stair section 72. To ensure the stability of the support, preferably, the third support 3 includes at least four third columns 31 and at least four third crossbars 32. The upper parts of two adjacent third columns 31 are connected by the third crossbars 32. The length of the two third crossbars 32 is arranged radially along the main body of the staircase. The height of the third crossbar 32 near the second spiral stair section 72 is higher than the height of the third crossbar 32 near the first spiral stair section 72. The third columns 31 are distributed on both sides of the first spiral stair section 71 and the second spiral stair section 72, with a distance of about 200mm from the spiral stair section. They are used to limit the spiral stair section. The third crossbars 32 arranged radially along the main body of the staircase are used to support the spiral stair section. The structure of the fourth support 4 is generally the same as that of the third support 3.

[0074] The second platform support 61 supports the second platform stair section 82, and the third platform support 62 supports the third platform stair section 83. The second and third platform supports 61 and 62 can be portal frame structures or other frame structures. Preferably, the second platform support 61 includes at least three fourth uprights 611 and at least three fourth crossbars 612, with the upper ends of two adjacent fourth uprights 611 connected by the fourth crossbars 612. The third platform support 62 has the same structure as the second platform support 61. Compared to the portal frame structure of the second and third platform supports 61 and 62, this structure has a larger area and is more stable.

[0075] The aforementioned supports 1, 2, 3, 3, 4, 51, 52, 61, and 62 are all temporary support structures and need to be cut and removed after the entire staircase installation is completed. Generally, this is done after the staircase tensioning is completed. This invention uses hoisting and temporary support methods to control the assembly and welding of each staircase segment. This not only ensures the stability of each segment during assembly and welding but also prevents deformation of the steel structure segments during welding, improving the accuracy of the staircase assembly and welding, and ensuring the overall staircase installation progress.

[0076] In step S3, the lower end of the cable 90 is typically connected to the lifting lugs of the platform and spiral stair sections via pins, forming a symmetrical tensioning structure. The cable 90 is pre-tensioned to 20% of the design tension value. Tensioning then begins, requiring a tensioning speed of ≤5kN / s for the cable 90, with each tensioning operation at 25% of the design value. The support reaction force on each individual stair section is measured every 12 hours. When the support reaction force decreases by 30%, the corresponding temporary supports are cut and removed, leaving 10% of the weld seam on each support as a safety reserve. The support reaction force refers to the weight of the stair section itself and the temporary loads experienced during construction. Once the support reaction force is ≤5kN and the displacement sensor data is stable, the remaining weld seams are cut, and all supports, including the first support 1, second support 2, third support 3, fourth support 4, first portal support 51, second portal support 52, second platform support 61, and third platform support 62, are completely cut and removed, completing the load transfer. Generally speaking, the cables bear 60% of the weight of the entire staircase, while the floor slab structure bears 40%.

[0077] Considering the minute structural deformations and geometric displacements that occur during the layered tensioning of the staircase, these minor deformations will propagate upwards along the spiral direction and accumulate. By the time construction reaches the top floor, its final elevation, position, and internal force distribution may have deviated from the initial design values. Furthermore, the cables will experience relaxation deformation after long-term tensioning. Therefore, supplementary tensioning of the top-floor platform staircase is necessary. Specifically, after layered tensioning of the staircase to 100% of the design value in step S3-b, supplementary tensioning of the top-floor staircase is required. Generally, the top-floor staircase should be tensioned to 102% of the design value within 48 hours to balance the internal forces of the entire staircase and correct the geometric deviations of the entire staircase.

[0078] The embodiments described herein are preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Therefore, all equivalent changes made in accordance with the structure, shape, and principle of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A method for installing a steel spiral staircase in the atrium of a stadium, characterized in that, Including steps, S1. Construction preparation work, including: S1-a. Select a crane that can enter the atrium of the venue based on the size of the venue entrance; S1-b, Divide the main body of the staircase into multiple platform stair sections and spiral stair sections. The weight of the spiral stair section and the platform stair section are both within the safe load of the crane selected in step S1-a. The platform stair section at the bottom is called the first platform stair section (81), and the spiral stair section at the bottom is called the first spiral stair section (71). S1-c, Level the ground in the atrium of the venue and draw the outline of the stairs on the ground; S1-d, make a first support (1) for supporting the lower end of the first platform stair section, a second support (2) for supporting the lower end of the first spiral stair section (71), and a third support (3) for supporting the upper end of the first spiral stair section (71). S2. Lifting operations include: S2-a. Erect the first support (1) and the second support (2) on the ground of the venue according to the outline of the first platform ladder section. After the crane enters the atrium of the venue and is in place, the crane is started to lift the first platform ladder section (81) to the preset position on the upper side of the first support (1) and the second support (2), and weld the platform end of the first platform ladder section (81) to the main steel beam of the first support (1) and the second floor slab of the venue, and weld the other end of the first platform ladder section (81) to the second support (2); S2-b, Install the connecting beam assembly (92) so that its upper end is on the top surface of the second bracket (2), and then assemble and weld the upper end of the connecting beam assembly (92) to the end of the first platform ladder (81) away from its upper platform ladder. The lower end of the connecting beam assembly (92) has a support leg fixed to the ground of the venue. S2-c, erect a third support (3) on the ground of the venue, hoist the first spiral stair section (71) and weld its lower end to the end face of the platform stair section of the first platform stair section (81), and weld the upper end of the first spiral stair section (71) to the top surface of the third support (3); S2-d. Temporary supports are welded on the ladder surface directly below the spiral ladder section and platform ladder section to be hoisted. The remaining spiral ladder sections and platform ladder sections to be hoisted are hoisted and assembled and welded to each other in the order of distribution from bottom to top. The platform ladder sections are all welded to the main steel beams on the corresponding floor slab. When the connecting beam assembly (92) is directly below the spiral stair section to be hoisted, the temporary support is welded to the third support (3); When the height difference between the top of the process staircase formed during the hoisting process and the ceiling (99) of the venue directly above it is within 6m, the remaining platform staircases and spiral staircases are hoisted in the order of distribution from top to bottom. S2-e, the crane leaves the venue and then the bottom extension frame section (91) is installed. S3. Install multiple cables (90) on the ceiling (99) of the venue, and connect the lower end of the cables (90) to each spiral stair section and platform stair section for layered tensioning. Cables (90) are symmetrically tensioned in the same spiral stair section or platform stair section. After the layered tensioning is completed, remove the first support (1), the second support (2), the third support (3) and the temporary support.

2. The method for installing a steel spiral staircase in a stadium atrium according to claim 1, characterized in that, The crane is a truck crane, and a single load-bearing steel plate is laid on the ground of the venue below the outriggers of the truck crane.

3. The method for installing a steel spiral staircase in a stadium atrium according to claim 1, characterized in that, Step S1 further includes step S1-e, which is carried out after step S1-d is completed; Step S1-e includes: setting and marking at least 4 lifting points on the platform stair section and the spiral stair section respectively, the shape formed by the sequential connection of the at least 4 lifting points is a rectangular structure, lifting lugs (80) are welded at the ends of the platform stair section and the spiral stair section, and the center line of gravity of the platform stair section and the spiral stair section is marked.

4. The method for installing a steel spiral staircase in a stadium atrium according to claim 1, characterized in that, The first support (1) includes at least four first columns (11) and a first crossbar (12) perpendicular to the first columns (11). The upper ends of two adjacent first columns (11) are connected by the first crossbar (12). The top surface height of the first crossbar (12) is the same as the bottom surface installation height of the platform section of the first platform staircase (81). The second support (2) is a portal frame structure and its top surface is at the same height position as the bottom surface of the end of the first platform staircase away from its platform section. It also includes at least two connecting rods (21), the first column (11) and the second bracket (2) are connected by the connecting rods (21); the top surface of the connecting rods (21) is flush with the top surface of the second bracket (2).

5. The installation and construction method for the steel structure spiral staircase in the atrium of a venue according to claim 3, characterized in that, Step S1-b is carried out after the crane selection in step S1-a is confirmed. Steps S1-c and S1-d are carried out simultaneously with steps S1-a or S1-b.

6. The method for installing a steel spiral staircase in a stadium atrium according to claim 4, characterized in that, The second support (2) includes two second columns (22) distributed on both sides of the first platform stair section (81) and a second crossbar (23) connecting the two second columns (22); the bottom surface of the first platform stair section (81) away from its platform section end and the bottom surface of the upper end of the connecting beam assembly (92) are both welded to the top surface of the second crossbar (23).

7. The method for installing a steel spiral staircase in a stadium atrium according to claim 1, characterized in that, Before starting step S2-b, a trial lifting operation must be performed on the platform ladder section and the spiral ladder section. The trial lifting operation includes: lifting the ladder section to 200mm above the ground and letting it stand for 10 minutes to observe the settlement of the crane outriggers. Subsequent lifting operations can only be carried out if the outrigger settlement is within 5mm and the angle between the sling and the horizontal plane is within 60°-90°. During the trial lifting, a force gauge should also be used to monitor and compare the force difference of each sling. If the center of gravity offset of the ladder section is greater than 100mm, a counterweight should be added to the raised end to make the horizontal deviation of the ladder section within 2mm / m.

8. The method for installing a steel spiral staircase in a stadium atrium according to claim 1, characterized in that, Before hoisting the spiral stair section located below the platform stair section in step S2-d, the platform stair section located above and adjacent to it is first hoisted and installed.

9. The method for installing a steel spiral staircase in a stadium atrium according to any one of claims 1-8, characterized in that, After step S3-b tensions the staircase to 100% of the design value in each layer, the top-floor staircase needs to be additionally tensioned to 102% of the design value.

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