Circular roof space tube truss structure and its construction method

Abstract

The present invention is a circular roof space tube truss structure and its construction method. The structure consists of five annular trusses, twelve radial trusses and twelve groups of radial support rods. The construction method is: add steel columns → manufacture, install and fix the conversion beam and the central support frame → move the radial truss support frame → hoist, assemble and install the inner ring truss → symmetrically install the radial truss → complete the whole circle of trusses in this cycle → the central support frame is synchronously unloaded in batches → qualified inspection → remove the support frame. The structure of the present invention is suitable for circular roofs with high height and large span built above the steel structure mezzanine. It has a high degree of matching with the main building and has sufficient strength, rigidity and stability. The construction method adopts a segmented assembly method, and multiple support systems are used to assist the construction, which ensures the accuracy of the component assembly size, improves the installation accuracy, and makes the installation quality deviation control higher than the national standard, and finally meets the requirements of quality, construction period, and safe construction.

Description

Technical Field

[0001] The invention belongs to the technical field of building construction, and particularly relates to a circular roof space tube truss structure which is suitable for a high height, a large span and is built above a steel structure interlayer, and a construction method thereof. Background Art

[0002] With the development of the times, various building structures have been applied, among which steel structure buildings are one of the most common building structures in current construction projects. However, in the context of rapid development of urban construction, the implementation of steel structure buildings often encounters many restrictions, such as: the shape of the main building, the height of the main building is too high, the span of the main building is too large, the construction period is tight, the construction site is narrow, the structural components are not suitable for factory prefabrication, the surrounding environment is not suitable for the use of large cranes, etc. These factors will limit the further development and popularization of steel structure buildings in terms of both structural design and construction methods. In addition, for some steel structure buildings with special requirements, the precision of their production, assembly and installation is relatively high, and the construction is relatively difficult. Summary of the invention

[0003] The purpose of the present invention is to solve the problems existing in the above-mentioned prior art and to provide a circular roof space tube truss structure suitable for high height, large span and built above the steel structure mezzanine and a construction method thereof.

[0004] The present invention is achieved through the following technical solutions:

[0005] A circular roof space tube truss structure built above the steel structure mezzanine, consisting of five circumferential trusses, twelve radial trusses and twelve groups of radial support rods;

[0006] The five ring trusses are the inner ring truss, the second ring truss, the third ring truss, the fourth ring truss and the outer ring truss which are concentrically arranged from the inside to the outside. The outer ring truss is supported and fixed by twelve bearings arranged on the top of the surrounding concrete columns.

[0007] Twelve radial trusses are evenly distributed and installed between five ring trusses in radial shape. The inner end and outer end of each radial truss are connected and installed with the inner ring truss and the outer ring truss respectively, and the part between the inner and outer ends is cross-connected and installed with the second ring truss, the third ring truss and the fourth ring truss respectively; each radial truss is assembled from two pieces of single trusses, and the single trusses are arranged in an arc shape in the plane, and the two pieces of single trusses are assembled in the way of arc joint connection;

[0008] Twelve groups of radial support rods are evenly distributed and installed radially between the three-ring trusses and the outer ring trusses, and the twelve groups of radial support rods and the twelve radial trusses are arranged in sequence; each group of radial support rods is composed of an upper chord arc rod and a lower chord arc rod with the same structure, and each chord arc rod is assembled from two arc rods, the outer ends of the two arc rods are butt-jointed and fixed to the outer ring truss, and the inner ends are separated and fixed to the three-ring truss.

[0009] As a preferred technical solution, the upper and lower chords of the inner ring truss are φ500×16, and the upper and lower chords of the other annular trusses are φ168×6; the upper chord of the radial truss is φ325×10, and the lower chord is φ273×14.

[0010] Furthermore, the construction method of the circular roof space tube truss structure built above the steel structure mezzanine includes the following steps:

[0011] 1) Add steel columns to the mezzanine

[0012] Four steel columns are added to the top of the concrete columns in the mezzanine facing the center of the circular roof, and the column heads of the steel columns are tightly connected to the top of the floor slab;

[0013] 2) Support of transfer beam and central support frame

[0014] The transfer beam is installed at the location where the steel column is set, the central support frame is installed on the transfer beam, and the top layer of the central support frame is laid with a platform plate, as follows:

[0015] The conversion beam and the central support frame are load-bearing frames composed of a lower structure and an upper structure. The conversion beam is the lower structure, specifically a quadrilateral frame structure formed by four conversion truss beams, with 25mm thick footboards at the four corners, which are installed at the floor position where the steel columns are installed; the central support frame is the upper structure, which is installed on the upper part of the conversion beam. The upper part of the central support frame is a regular hexagonal frame. The circumscribed circle of the regular hexagon is the center line of the inner ring truss. The top layer of the central support frame is paved with a platform plate, and the height of the platform plate is 400mm lower than the lower chord of the inner ring truss. I-beam piers are installed at the six columns outside the regular hexagon to form six support points for supporting the inner ring truss to be installed.

[0016] 3) Inner ring truss installation

[0017] First, divide the inner ring truss into four pieces and place them on the ground, then hoist them to the central support frame for assembly and welding, as follows:

[0018] Before installation, lay out the lines on the platform plate of the center support frame, lay out the center origin and the inner ring plane positioning control line, lay out the node positions of the twelve radial trusses on the platform plate, and support the six columns on the platform plate located outside the center support frame as the support points for the inner ring trusses. Due to the weight limitation of the on-site tower crane, the inner ring trusses are assembled on the floor. First, the lower chord ring and the vertical web members and diagonal web members of the inner ring truss are assembled and formed, and then divided into four pieces and hoisted to the center support frame for assembly and welding. Then, the upper chord ring made on the floor is divided into four pieces and hoisted and assembled to form and complete the welding of the connecting nodes.

[0019] 4) Radial truss installation

[0020] The radial trusses are installed symmetrically, specifically: install the first radial truss, then install the seventh radial truss → install the second radial truss, then install the eighth radial truss → install the third radial truss, then install the ninth radial truss → install the fourth radial truss, then install the tenth radial truss → install the fifth radial truss, then install the eleventh radial truss → install the sixth radial truss, then install the twelfth radial truss;

[0021] Each radial truss is installed in a piece-by-piece vertical bulk manner, that is, one piece of arc-shaped single truss is installed first, and then the other piece of arc-shaped single truss is installed; the inner end of each radial truss is connected and installed with the inner ring truss, and the outer end is connected and installed with the support set on the top of the surrounding concrete column; after the installation of each radial truss is completed, the second ring truss, the third ring truss, and the fourth ring truss are installed, which are located between the two pieces of arc-shaped single trusses of each radial truss. When installing, the third ring truss in the middle should be installed first, and then the second ring truss and the fourth ring truss on both sides should be installed;

[0022] When installing the next adjacent radial truss, after one of the arc-shaped mono-trusses of the next radial truss is installed, first install the second ring truss, the third ring truss, the fourth ring truss, and the outer ring truss located between the two adjacent radial trusses. After the installation of the second ring truss, the third ring truss, the fourth ring truss, and the outer ring truss are installed. After the installation of the second ring truss, the third ring truss, and the fourth ring truss are installed between the two arc-shaped mono-trusses. This process is repeated to complete the installation of all radial trusses in the circumference.

[0023] During the installation of the radial truss, a radial truss support frame is provided in the middle support thereof;

[0024] 5) Unloading of support frame

[0025] Install and weld according to the above process sequence and method, and unload after completion; the unloading is divided into two parts, the first part is the unloading of the radial truss support frame, and the second part is the unloading of the central support frame. After all the radial truss support frames are unloaded, the central support frame is unloaded;

[0026] The unloading of the radial truss support frame is performed by first unloading the first radial truss support frame and the seventh radial truss support frame, and then sequentially unloading the second radial truss support frame and the eighth radial truss support frame, the third radial truss support frame and the ninth radial truss support frame, the fourth radial truss support frame and the tenth radial truss support frame, the fifth radial truss support frame and the eleventh radial truss support frame, the sixth radial truss support frame and the twelfth radial truss support frame;

[0027] The unloading of the central support frame adopts the stepwise synchronous unloading method. When unloading, a 25t hydraulic jack is used next to each of the six supporting points of the inner ring truss to push up to the lower chord of the inner ring truss, and the I-beam pier is removed. At this time, the six jacks are used for support. The six jacks are controlled to unload synchronously each time, and the unloading height is 10mm each time until the unloading is completed and the structure completes the force conversion;

[0028] 6) Installation of twelve sets of radial support rods

[0029] After unloading is completed, twelve groups of radial support rods are assembled and welded in sequence on the integral roof truss structure using the high-altitude bulk method;

[0030] 7) Support fixation

[0031] After all structural members are installed, tighten the surrounding support bolts again and secure them firmly. The entire structure is inspected and tested, and the center support frame can be removed after passing the inspection.

[0032] As a preferred technical solution, the height of the steel column is 4 cm lower than the net height of the mezzanine. After the steel column is in place, four jacks are used to tighten the column head to the floor slab, and inclined pads are added around the bottom of the column. After the jacks are removed, a 600*600 side formwork is supported and C60 high-strength non-shrinkage grouting material is poured from one end to fill the gap at the bottom of the column tightly.

[0033] As a preferred technical solution, the central support frame includes seven vertically arranged main support steel columns, six of which are evenly distributed along a circle of the inner ring truss, and the remaining main support steel column is distributed along the center of the inner ring truss. Horizontal rods are connected and fixed between adjacent main support steel columns; the platform plate on the top of the central support frame is 12 mm thick, and a jack is arranged on the platform plate to fine-tune the position of the assembled inner ring truss. During adjustment, two people raise the jack synchronously, and prepare steel plates of different thicknesses for adjustment. After adjustment and verification, the steel plate is welded and fixed.

[0034] As a preferred technical solution, when the first radial truss is installed, four guy ropes are used for temporary tensioning to prevent it from tipping over, so as to ensure the stability of one side of the central support frame when loaded; when the first arc-shaped single truss of the adjacent second radial truss is not tensioned with the first radial truss, the tower crane is connected to the annular truss without loosening the hook.

[0035] The space tube truss structure of the present invention is suitable for circular roofs with high heights and large spans built above the steel structure mezzanine. It is assembled by reasonable segmentation, has a high degree of matching with the main building, and has sufficient strength, rigidity and stability. The construction method of the space tube truss structure of the present invention is scientific and reasonable. It can be completed by hoisting construction through an on-site tower crane and utilizing the effective radius and rated lifting capacity of the tower crane itself, which well solves the problem of difficulty in activating other equipment for construction due to the small construction site. The method uses a clever segmented assembly method to install the truss structure, and at the same time, multiple support systems are set up to assist in construction, ensuring the accuracy of the component assembly size, playing a key role in the assembly and welding quality of the truss, improving the installation accuracy, and making the installation quality deviation control higher than the national standard, ultimately meeting the requirements of quality, construction period, safe construction, etc., and giving full play to the role of science and technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The drawings herein are used to provide further explanation of the present invention and constitute a part of this application. The illustrative embodiments of the present invention and their description are used to explain the present invention and do not constitute improper limitations on the present invention.

[0037] Figure 1 It is a three-dimensional schematic diagram of the circular roof space tube truss structure of the present invention.

[0038] Figure 2 It is a cross-sectional schematic diagram of the circular roof space tube truss structure of the present invention.

[0039] Figure 3 It is a schematic diagram of the conversion beam and the central support frame in the present invention.

[0040] Figure 4 for Figure 3 Top view of the .

[0041] Figure 5 It is a schematic diagram of the building axis of the circular roof space tube truss structure of the present invention.

[0042] Figure 6 It is a schematic diagram of the distribution of steel columns in the present invention.

[0043] Figure 7 It is a schematic diagram of the installation of steel columns in the present invention.

[0044] Figure 8It is a schematic diagram of the single truss and tire frame in the present invention.

[0045] Fig. 9 for Figure 8 Elevation drawing of .

[0046] Fig.10 for Figure 8 Vertical cross-sectional view of .

[0047] Fig.11 Schematic diagram of the radial truss installation sequence in the method of the present invention.

[0048] Fig.12 The diagram is a schematic diagram of the first arc-shaped single truss for installing the first radial truss in the method of the present invention.

[0049] Fig.13 The diagram is a schematic diagram of the second arc-shaped single truss for installing the first radial truss in the method of the present invention.

[0050] Fig.14 The diagram is a schematic diagram of installing the two-ring truss, three-ring truss and four-ring truss parts within the first radial truss in the method of the present invention.

[0051] Fig.15 It is a schematic diagram of installing the seventh radial truss in the method of the present invention.

[0052] Fig.16 It is a schematic diagram of the first arc-shaped single truss for installing the second radial truss in the method of the present invention, and the second ring truss, the third ring truss, the fourth ring truss and the outer ring truss between the first and second radial trusses.

[0053] Fig.17 It is a schematic diagram of the second arc-shaped single truss for installing the second radial truss in the method of the present invention and the two-ring truss, three-ring truss and four-ring truss parts between the second radial truss.

[0054] Fig.18 It is a schematic diagram of installing the eighth radial truss in the method of the present invention.

[0055] In the figure: 1-inner ring truss, 2-two-ring truss, 3-three-ring truss, 4-four-ring truss, 5-outer ring truss, 6-radial truss, 6-1-monomeric truss, 7-steel column, 8-jack, 9-conversion beam, 10-center support frame, 11-radial truss support frame, 12-tire frame, 13-radial support rod, a-first radial truss, b-seventh radial truss, c-second radial truss, d-eighth radial truss. DETAILED DESCRIPTION

[0056] In order to make those skilled in the art better understand the present invention, the present invention is further clearly and completely described below in conjunction with the accompanying drawings and embodiments. It should be noted that the embodiments and features in the embodiments of the present application can be combined with each other without conflict.

[0057] like Figure 1 As shown, a circular roof space tube truss structure built above the steel structure mezzanine is composed of five circumferential trusses, twelve radial trusses 6 and twelve groups of radial support rods 13;

[0058] The five ring trusses are respectively an inner ring truss 1, a second ring truss 2, a third ring truss 3, a fourth ring truss 4 and an outer ring truss 5 which are arranged concentrically from the inside to the outside. The outer ring truss 5 is supported and fixed by twelve bearings arranged on the tops of the surrounding concrete columns.

[0059] Twelve radial trusses 6 are evenly distributed and installed between the five annular trusses in a radial shape. The inner end and the outer end of each radial truss 6 are connected and installed with the inner ring truss 1 and the outer ring truss 5 respectively, and the part between the inner and outer ends is cross-connected and installed with the second ring truss 2, the third ring truss 3, and the fourth ring truss 4 respectively; each radial truss 6 is assembled by two pieces of single trusses 6-1, and the single truss 6-1 is arranged in an arc shape in the plane, and the two pieces of single trusses 6-1 are assembled in a way of arc joint;

[0060] Twelve groups of radial support rods 13 are evenly distributed radially between the three-ring truss 3 and the outer ring truss 5, and the twelve groups of radial support rods 13 and the twelve radial trusses 6 are arranged in sequence; each group of radial support rods 13 is composed of an upper chord arc rod and a lower chord arc rod with the same structure, and each chord arc rod is assembled from two arc rods, the outer ends of the two arc rods are butt-jointed and fixed to the outer ring truss 5, and the inner ends are separately arranged and both are fixed to the three-ring truss 3.

[0061] In the above structure, the upper and lower chords of the inner ring truss 1 are φ500×16, and the upper and lower chords of the other annular trusses are φ168×6; the upper chord of the radial truss 6 is φ325×10, and the lower chord is φ273×14.

[0062] The construction method of the circular roof space tube truss structure built above the steel structure mezzanine includes the following steps:

[0063] 1) Add steel columns to the mezzanine

[0064] like Figure 6 , Figure 7As shown, four steel columns 7 are added to the top of the concrete column at the center of the circular roof in the mezzanine, and the column heads of the steel columns 7 are pressed tightly against the floor slab; the height of the steel columns 7 is 4 cm lower than the net height of the mezzanine. After the steel columns 7 are in place, four jacks 8 are used to press the column heads against the floor slab, and inclined pads are added around the bottom of the column. After the jacks 8 are removed, a 600*600 side form is supported and C60 high-strength non-shrinkage grouting material is poured from one end to fill the gap at the bottom of the column tightly.

[0065] 2) Support of transfer beam and central support frame

[0066] like Figure 3 , Figure 4 As shown, the conversion beam 9 and the central support frame 10 are load-bearing frames composed of a lower structure and an upper structure. The conversion beam 9 is a lower structure, specifically a quadrilateral frame structure formed by four conversion truss beams, and 25mm thick support plates are set at the four corners. The support plates are installed at the floor position where the steel column 7 is set; the central support frame 10 is an upper structure, which is installed on the upper part of the conversion beam 9. The central support frame 10 includes seven vertically arranged columns, six of which are arranged along the inner ring truss 1. Evenly distributed, the remaining column is distributed along the center of the inner ring truss 1, and horizontal rods are connected and fixed between adjacent columns. The upper part of the central support frame 10 is a regular hexagonal frame, and the circumscribed circle of the regular hexagon is the center line of the inner ring truss 1. The top layer of the central support frame 10 is paved with a platform plate, and the height of the platform plate is 400mm lower than the lower chord of the inner ring truss 1. I-beam piers are installed at the six column positions outside the regular hexagon respectively, forming six support points for supporting the inner ring truss 1 to be installed.

[0067] 3) Inner ring truss installation

[0068] First, the inner ring truss 1 is evenly divided into four pieces and placed on the ground, and then hoisted to the central support frame 10 for assembly and welding, as follows:

[0069] Before installation, lay out the lines on the platform plate of the central support frame 10, lay out the center origin and the inner ring plane positioning control lines, lay out the node positions of the twelve radial trusses 6 on the platform plate, and support the six columns on the platform plate located on the periphery of the central support frame 10 as the support points for the inner ring truss 1. The inner ring truss 1 is assembled and manufactured on the floor. First, the lower chord ring and the vertical web members and diagonal web members of the inner ring truss 1 are assembled and formed, and then divided into four pieces and hoisted onto the central support frame 10 for assembly and welding. Then, the upper chord ring manufactured on the floor is divided into four pieces and hoisted and assembled to complete the welding of the connecting nodes.

[0070] 4) Radial truss installation

[0071] The radial trusses 6 are installed symmetrically. Figure 6As shown, specifically: install the first radial truss a, then install the seventh radial truss b → install the second radial truss c, then install the eighth radial truss d → install the third radial truss, then install the ninth radial truss → install the fourth radial truss, then install the tenth radial truss → install the fifth radial truss, then install the eleventh radial truss → install the sixth radial truss, then install the twelfth radial truss;

[0072] Each radial truss 6 is installed in a piecewise vertical bulk manner, that is, one piece of arc-shaped single truss 6-1 is installed first, and then another piece of arc-shaped single truss 6-1 is installed; the inner end of each radial truss 6 is connected and installed with the inner ring truss 1, and the outer end is connected and installed with the support set on the top of the surrounding concrete column; after each radial truss 6 is installed, the second ring truss 2, the third ring truss 3, and the fourth ring truss 4 are installed, which are respectively located between the two pieces of arc-shaped single trusses 6-1 of each radial truss 6. When installing, the third ring truss 3 in the middle should be installed first, and then the second ring truss 2 and the fourth ring truss 4 on both sides should be installed;

[0073] When installing the next adjacent radial truss 6, after one of the arc-shaped monolithic trusses 6-1 of the next radial truss 6 is installed, the second ring truss 2, the third ring truss 3, the fourth ring truss 4, and the outer ring truss 5, which are respectively located between the two adjacent radial trusses 6, must be installed first. After the installation of this part is completed, continue to install another arc-shaped monolithic truss 6-1. After the installation of the two arc-shaped monolithic trusses 6-1 is completed, continue to install the second ring truss 2, the third ring truss 3, and the fourth ring truss 4, which are respectively located between the two arc-shaped monolithic trusses 6-1; and so on, complete the installation of all radial trusses 6 in the circumference;

[0074] When the first radial truss is installed, four guy ropes are used for temporary tensioning to prevent it from falling. When the first arc-shaped single truss of the adjacent second radial truss is not tensioned with the first radial truss, the tower crane is connected to the annular truss without releasing the hook;

[0075] During the installation of the radial truss 6, a radial truss support frame 11 is provided in the middle thereof. Figure 2 shown.

[0076] 5) Unloading of support frame

[0077] Install and weld according to the above process sequence and method, and unload after completion; the unloading is divided into two parts, the first part is the unloading of the radial truss support frame 11, and the second part is the unloading of the central support frame 10. After all the radial truss support frames 11 are unloaded, the central support frame 10 is unloaded;

[0078] The unloading of the radial truss support frame 11 is performed by first unloading the first radial truss support frame and the seventh radial truss support frame, and then sequentially unloading the second radial truss support frame and the eighth radial truss support frame, the third radial truss support frame and the ninth radial truss support frame, the fourth radial truss support frame and the tenth radial truss support frame, the fifth radial truss support frame and the eleventh radial truss support frame, the sixth radial truss support frame and the twelfth radial truss support frame;

[0079] The unloading of the central support frame 10 adopts the stepwise synchronous unloading method. When unloading, a 25t hydraulic jack is used to push up to the lower chord of the inner ring truss 1 next to each of the six supporting points supporting the inner ring truss 1, and the I-beam pier is removed. At this time, six jacks are used for support, and the six jacks are controlled to unload synchronously each time. The unloading height is 10mm each time until the unloading is completed and the structure completes the force conversion.

[0080] 6) Installation of twelve sets of radial support rods

[0081] After unloading is completed, twelve groups of radial support rods 13 are assembled and welded in sequence on the integral roof truss structure using a high-altitude bulk method. For the sake of simplicity and clarity of the attached drawings, Figure 1 Only a schematic diagram of a group of radial support rods 13 is shown, but in reality a group of radial support rods 13 is provided between adjacent radial trusses 6;

[0082] 7) Support fixation

[0083] After all structural members are installed, the peripheral support bolts are tightened again and fixed firmly, and the entire structure is inspected and tested. After passing the inspection, the central support frame 10 can be removed.

[0084] A specific embodiment is listed below to further illustrate the technical solution of the present invention:

[0085] 1. Project Overview and Features

[0086] 1. Project Overview

[0087] The specific embodiment project listed is the roof steel structure project of the control center of the first phase of the Taiyuan Metro Line 2 project in Shanxi Province. The steel structure is a circular roof space tube truss structure with a span of 59.4 meters. It is composed of twelve radial trusses 6, five annular trusses and twelve groups of "small petal"-shaped radial support rods 13. The outer ring truss 5 is supported by twelve supports set on the tops of the surrounding concrete columns. The elevation of the surrounding supports of the roof steel structure is 40.500m, and the floor elevation is 30.420m. The upper and lower chords of the inner ring truss 5 are φ500×16, and the upper and lower chords of the other annular trusses are φ168×6; the upper chord of the radial truss 6 is φ325×10, and the lower chord is φ273×14. The circular roof space tube truss structure is as follows Figure 1 , Figure 2 , Figure 5 shown.

[0088] The single curved monolithic truss of the radial truss in this project is as follows Figure 8 , Fig. 9 As shown, the weight is approximately 6.15t tons.

[0089] 2. Project Features

[0090] (1) This project is a circular roof steel structure with a large span and a diameter of 58.8m. The components are arc-shaped in the plane, which requires high precision in manufacturing, assembly and installation, and is difficult to construct.

[0091] (2) The project was under tight schedule and had a narrow site. The structural components were not suitable for factory prefabrication and had to be shipped to the site for assembly and installation, which brought certain difficulties to the construction organization and management.

[0092] (3) The steel structure layer is located at the upper part of the frame structure. It is high and has a large span. The surrounding environment is not suitable for the use of large cranes outside the span. Only the tower crane on site can be used. According to the rated lifting capacity of the tower crane within the effective radius, the central support frame is designed to support the inner ring truss. The inner ring truss is divided into four pieces and hoisted separately. The twelve radial trusses are divided into 24 arc-shaped single trusses and hoisted separately. The high-altitude assembly and installation is somewhat difficult.

[0093] (4) The welding quality of the tube-to-tube butt welds and intersecting connection node welds of steel tube trusses has a significant impact on structural safety. Strict welding procedures must be formulated to ensure welding quality.

[0094] 2. Site conditions

[0095] 1. The lower layer of the circular roof layer is a steel structure mezzanine, the mezzanine plate is a floor deck, the plate top elevation is 30.42m, the plate thickness is 125mm, and the concrete strength is C30; the lower part of the mezzanine is a concrete frame, the plate top elevation is 28.48m, the frame column is 800mm*800mm, and the column distance is 8.4m*8.4m.

[0096] 2. The perimeter support of the on-site roof steel structure is at the top of the reinforced concrete beam at 40.5m.

[0097] 3. The tower cranes arranged on site are TC7013 tower crane with a 70m arm length and 6015 tower crane with a 60m arm length.

[0098] 3. Overall construction plan

[0099] According to the roof structure and on-site construction conditions, a temporary support frame positioning and installation method is used. This support frame positioning and installation method is to design and install a reasonable central support frame with a conversion beam and a middle support frame with an arc-shaped radial beam, and then hoist and install the components to the designed position of the structural components in a certain installation process sequence, and then assemble, calibrate, and weld to connect and fix them. This installation method requires setting up a support system under the components, and then reasonably unloading after the components are connected, so as to convert the structural force to the structural design force system.

[0100] First, four steel columns are added to the top of the concrete column at the center support frame position in the mezzanine. A conversion beam is set on the upper part of the mezzanine plate, and a fixed center support frame is set at the lower part of the inner ring truss to install the inner ring truss. The center support frame is set on the conversion beam to transfer the upper load to the additional steel column at the lower part. A tower crane is used for lifting. In order to meet the lifting requirements within the operating radius, the inner ring truss is divided into four pieces and installed on the center support frame. The radial truss is installed in bulk in pieces, and a radial truss support frame is added in the middle. It is installed symmetrically. After the installation of two adjacent radial trusses and connecting rods is completed, it can be unloaded. After all structural components are installed, the center support frame can be unloaded.

[0101] The overall construction sequence is: add steel columns → manufacture, install and fix the conversion beam and center support frame → move the radial truss support frame (consider the symmetrical number) → hoist, assemble and install the inner ring truss → symmetrically install the radial truss → complete the entire circle of trusses in this cycle → unload the center support frame synchronously in batches → pass the inspection → remove the center support frame.

[0102] 4. Design of transfer beam and central support frame

[0103] The central support frame of this project is designed with a diameter of 10m according to the inner ring truss. Seven H-shaped steel columns of 500*200**12*16 are evenly distributed on the circle with a diameter of 10m and at the center of the circle, and four H-shaped steel columns of 250*250*9*12 are added on the transfer beam; the column height of the central support frame steel column is 9.6m, and horizontal bars are set every 3.2m in the middle of the steel column. The top is a platform beam, and the horizontal bars and platform beams are made of H-shaped steel 200*200*8*12; the central support frame is equipped with a lattice transfer beam on the ground, and the transfer beam support is 500*50*20, the upper and lower chords of the transfer beam are made of H-shaped steel 200*200*8*12, the web members are made of H-shaped steel 150*150*7*10, and the upper part is fully covered with 10mm platform plates; the sandwich steel columns are made of 350*350*20 square tubes. According to the predetermined construction conditions, MIDAS software is used to perform finite element analysis and safety verification to meet the construction technology and safety requirements. Figure 3 , Figure 4 shown.

[0104] 5. Tire frame design

[0105] The arc-shaped monomer truss of the radial truss is assembled vertically, and the design assembly frame 12 is used. The bottom platform frame and the column are H250*125*6*9, the base width is 3m, the column height is 3.6m, the upper column and the column are connected with a square tube of 120*120*4, the column diagonal brace is 60*60*3 square tube, the upper column bracket is H250*125*6*9, which is used to support and adjust the height of the upper chord steel pipe. The end of the bracket and the outer side of the lower chord pipe are connected with the stop iron with bolts. Figure 8 , Fig. 9 , Fig.10 shown.

[0106] 6. Radial Truss Support Frame Design

[0107] Since the radial truss is arc-shaped outside the plane, it needs three-point support at both ends and the middle area during installation to prevent eccentric flipping or twisting. A lattice radial truss support frame is set in the middle, and a 6m long 200*200*8*12H-shaped steel base is set at the bottom of the frame. The column height is 9.6m, and φ60*3.5 round tubes are used. The plane size of the frame is 1.2m*1.2m. The column center plate is made of φ60*3.5 round tubes with a spacing of 1.3m. The radial truss support frame is as follows Figure 2 The radial truss support frame is fixed with a guy rope, and the two adjacent radial trusses (four-piece arc-shaped single trusses) are removed after installation and welding, and the radial trusses are installed symmetrically in sequence.

[0108] 7. Construction technology

[0109] 1. Processing requirements

[0110] (1) Draw an enlarged sample of the nodes on the drawing (the intersection line part is completed online by the intersection line equipment), and all materials can be cut after the enlarged sample is completed and verified.

[0111] (2) All materials must be inspected and qualified before they can be put into use (the original materials must be re-inspected).

[0112] 2. Add steel columns to the mezzanine

[0113] (1) If Figure 5 , Figure 6 As shown, a 350*350*20 box-type steel column is added to the top of the concrete column where the mezzanine 4, 5 axes intersect with the P, N axes. The column head plate and column foot plate are both 500*500*20 steel plates. In order to facilitate on-site installation, they are manufactured in sections and butt-welded during on-site installation.

[0114] (2) If Figure 7 As shown in the figure, the height of the steel column is 4cm lower than the net height of the mezzanine. After the steel column is in place, four jacks are used to tighten the column head to the floor slab, and inclined pads are added around the bottom of the column. After the jacks are removed, a 600*600 side form is supported and C60 high-strength non-shrinkage grouting material is poured from one end to fill the gap at the bottom of the column tightly.

[0115] 3. Installation of transfer beam and central support frame

[0116] (1) Before installation, the frame foundation and center support frame should be positioned, laid out and closed.

[0117] (2) Lay out the center position on the ground and install the transfer beam and center support frame according to the laid out position. Figure 2 shown.

[0118] (3) A 500*500*20 thick steel plate is installed at the support position of the transfer beam, and a 12mm thick rib is added to strengthen the node.

[0119] (4) The connection nodes of the transfer beam and the center support frame shall be constructed according to the detailed drawings of the design standard nodes, and the node welds shall strictly comply with the quality requirements of the detailed drawings to ensure the quality of the welds.

[0120] (5) The transfer beam and center support frame are assembled and installed in situ, and monitoring is carried out during the installation process to ensure installation accuracy.

[0121] (6) In the calculation of the simulated construction process, the frame meets the stability requirements. The dynamic load during the construction process is taken into account to avoid the frame from deflecting under the load. After the installation is completed, the surrounding cables are evenly distributed and tied to the surrounding frame columns.

[0122] (7) After the overall installation of the center support frame is accepted, a 12mm thick platform board is laid on the top layer.

[0123] 4. Inner ring truss installation

[0124] (1) The inner ring truss located in the center circle has a diameter of 10m and a total length of 31.416m. After being assembled in a full circle on the ground, it can be disassembled into four pieces and hoisted to the top of the center support frame for assembly.

[0125] (2) A jack is set up on the top of the middle support frame to fine-tune the position of the assembled inner ring truss. During the adjustment, two people lift the jack simultaneously, and prepare steel plates of different thicknesses such as 3mm and 5mm for adjustment. After the adjustment is verified, the steel plates are welded and fixed.

[0126] (3) To ensure the stability of the arc tube during high-altitude assembly, four additional support points are added and supported by brackets. To ensure the stability of the bracket, it is reliably connected to the central support frame. During the support process, the deviation between the positioning pile point and the frame is monitored at any time, and timely adjustments are made to ensure the accurate positioning of the inner ring truss.

[0127] (4) After segmentation, the weight of each curved beam is 4.8 t. It is hoisted by a 7015 tower crane with a hoisting distance of 37 m. A three-point hoisting method is adopted. A 10 t fall chain is set in the middle of the curved beam to adjust the balance of the curved beam.

[0128] (5) After the inner ring truss assembly and welding are accepted, the nodes connected to the radial truss are positioned, assembled and welded.

[0129] 5. Radial truss installation

[0130] (1) After the inner ring truss installation inspection is passed, the radial truss can be installed.

[0131] (2) Install the first curved monolithic truss of the first radial truss, such as Fig.12 shown.

[0132] (3) Install the second curved monolithic truss of the first radial truss, such as Fig.13 shown.

[0133] (4) Install the annular truss part inside the first truss, that is, the part of the second-ring truss, third-ring truss, and fourth-ring truss located inside the first radial truss. First install the third-ring truss in the middle, and then install the second and fourth-ring trusses on both sides. Fig.14 shown.

[0134] (5) Install the seventh radial truss using the same method as steps (2), (3), and (4) above. Fig.15 shown.

[0135] (6) Install the first arc-shaped monolithic truss of the second radial truss, and install the annular truss portion between the first and second radial trusses, i.e., the portion of the second-ring truss, the third-ring truss, the fourth-ring truss, and the outer-ring truss located between the first and second radial trusses, such as Fig.16 shown.

[0136] (7) Install the second curved monolithic truss of the second radial truss and the two-ring truss, three-ring truss, and four-ring truss parts located within the second radial truss, such as Fig.17 shown.

[0137] (8) Install the eighth radial truss in the same way. Fig.18 shown.

[0138] (9) Similarly, complete the installation of the circumferential radial truss. Figure 1 shown.

[0139] (10) During the installation of the radial truss, a radial truss support frame is set in the middle of the truss beam. The support base is put in place by laying out the wires. The support is hoisted into place by a tower crane and connected to the base with bolts. The two supports of the same radial truss are connected by horizontal rods and cross supports. The radial direction is supported by 70*7 equilateral angle steels, such as Figure 2 shown.

[0140] (11) When the first radial truss is installed, four guy ropes are used for temporary tensioning to prevent it from tipping over. When the first arc-shaped single truss of the second radial truss is not tied to the first radial truss, the tower crane is connected to the ring truss without releasing the hook.

[0141] (12) During the specific implementation, the lifting distance of the fourth, fifth, sixth, seventh and eighth radial trusses exceeded 45 meters, and the tower crane did not meet the lifting operation conditions, so it was split into two parts and assembled and connected in the air. In order to ensure the assembly accuracy of the trusses, the curved trusses were made as a whole on the ground and then split and hoisted.

[0142] (13) Before a single hoisting component forms a structural system, it is secured with cables.

[0143] (14) Temporary vertical poles are added at the end support positions of the segmented beams to ensure that the structure does not deform when spliced.

[0144] 6. Installation of twelve sets of radial support rods

[0145] After the unloading is completed, twelve groups of radial support rods 13 are assembled and welded in sequence on the integral roof truss structure formed by high-altitude bulk method;

[0146] 7. Unloading of support frame

[0147] (1) The whole truss can be unloaded only after it has been installed and monitored. The unloading is divided into two parts. The first part is the unloading of the radial truss support frame 11, and the second part is the unloading of the central support frame 10. After all the radial truss support frames 11 are unloaded, the central support frame 10 is unloaded;

[0148] The unloading of the radial truss support frame 11 is performed by first unloading the first radial truss support frame and the seventh radial truss support frame, and then sequentially unloading the second radial truss support frame and the eighth radial truss support frame, the third radial truss support frame and the ninth radial truss support frame, the fourth radial truss support frame and the tenth radial truss support frame, the fifth radial truss support frame and the eleventh radial truss support frame, the sixth radial truss support frame and the twelfth radial truss support frame;

[0149] The unloading of the central support frame 10 adopts the stepwise synchronous unloading method. When unloading, a 25t hydraulic jack is used to push up to the lower chord of the inner ring truss 1 next to each of the six supporting points supporting the inner ring truss 1, and the I-beam pier is removed. At this time, six jacks are used for support, and the six jacks are controlled to unload synchronously each time. The unloading height is 10mm each time until the unloading is completed and the structure completes the force conversion.

[0150] (2) After the structure completes the force conversion, the deflection of the roof truss structure is tested.

[0151] 8. Peripheral support fixation

[0152] After the deflection test of the roof truss structure meets the design requirements, check and tighten the support fixing bolts again, and spot weld the fixing nuts according to the design requirements.

[0153] 9. Removal of support frame

[0154] (1) The jack and bracket can be removed only after the overall deflection meets the requirements and the surrounding support bolts are tightened.

[0155] (2) When dismantling the central support frame, use gas cutting to dismantle it in layers. When hoisting, use the inner circle space of 10m diameter of 7015 tower crane to prevent structural instability during the dismantling process. If necessary, add temporary support at any time.

[0156] (3) The lifting weight must be calculated when removing parts, and the removal and movement can only be carried out after confirming that the removed section is completely separated from the lower section.

[0157] (4) During the demolition process, a sliding rope is installed in the demolished section to prevent collision with the installed roof truss structure; a wind cable is promptly installed in the undemolished section to prevent tipping.

[0158] 10. Key points of construction control

[0159] (1) A lining plate with a thickness of 6 mm is added to the connection node between the inner ring truss HJ-2 and the radial truss HJ-1 in the 500×18 diameter tube. The weld is a full penetration weld.

[0160] (2) The butt welds between all horizontal members of the inner ring truss and radial truss are full penetration welds.

[0161] (4) The bending of the rod should be done on a pipe bending machine. The heating temperature should be strictly controlled during hot bending. The rod should be cooled naturally after hot bending. The bending arc is allowed to be negative but not positive, and the bending arc diameter deviation is ≤10mm.

[0162] (5) The cutting length of the rod should take into account the welding shrinkage allowance. The cutting length should be controlled at ±1mm. A reasonable assembly gap should be retained at the intersection of the diagonal web and the upper and lower diaphragm rods to ensure the thickness of the weld.

[0163] (6) Production and installation

[0164] 1) Process flow

[0165] Deepen the design of drawings → Acceptance and re-inspection of raw materials → Bending pipe processing → Cutting → Rust removal and painting → Steel column reinforcement → Erection of center support frame 10 → Fabrication and installation of inner ring truss 1 → Fabrication and installation of radial truss 6 → Assembly of twelve sets of “small petals” radial support rods 13 → Weld inspection → Truss unloading → Deflection detection → Repainting and topcoat spraying → Data sorting and archiving → Handover.

[0166] 2) Use BIM software to establish a three-dimensional model, and compile component and part processing details, component assembly and structural installation layout drawings in accordance with the predetermined manufacturing, assembly and installation processes, laying the foundation for accurate component manufacturing and installation, and conduct engineering simulation analysis and safety verification to eliminate safety hazards during the construction process.

[0167] 3) On-site acceptance of steel is carried out in accordance with document acceptance and physical acceptance. Document acceptance is to check and verify whether the purchase list and order contract are consistent, and whether the accompanying product certificate and performance test report meet the requirements of relevant specifications and order contracts. Physical acceptance is to carefully check whether the specifications, appearance quality, and surface corrosion degree of the steel meet the design and relevant specifications, and witness sampling and re-inspection in accordance with the current national standards to ensure that the steel used meets the requirements of engineering construction.

[0168] 4) Pipe bending

[0169] The pipe bending process is carried out in the factory. Pipes with a diameter of less than 325mm are processed by hydraulic cold bending equipment, and steel pipes with a diameter of 500mm are processed by high-frequency hot bending equipment. The heating temperature is strictly controlled during processing to prevent the steel material from being affected, and the bending accuracy is controlled. The bending height of the steel pipe is ≤5mm, and the roundness deviation of the pipe mouth is not more than 2mm.

[0170] 5) Cutting

[0171] The cutting process is carried out in the factory. The cutting of pipe fittings is completed by CNC intersecting line cutting cutting machine. A reasonable cutting sequence is adopted and cutting line compensation is added during cutting. The size of pipe fittings, the geometric shape of the intersecting line, the size and accuracy of the groove are strictly controlled.

[0172] 6) Rust removal and painting

[0173] Use shot blasting machine to remove rust, control the rust removal level and surface roughness, and control the surface roughness within 50-80μm to enhance the adhesion of the coating. When painting, use tape to protect the area within 100mm where welding is required.

[0174] 7) Steel column reinforcement

[0175] Steel columns 7 are added between the concrete columns of the lower layer of the mezzanine floor and the top of the mezzanine for reinforcement, so that the upper load is transferred to the concrete columns of the lower layer that can be used for bearing through the central support frame 10, the transfer beam 9, and the steel columns 7. When reinforcing the steel columns 7, in order to ensure the quality of reinforcement, the steel columns 7 are lifted up with jacks 8, so that the top plate of the columns fits tightly with the floor slab, and inclined pads are installed at the bottom, and the gap at the bottom of the columns is filled with C60 high-strength non-shrinkage grouting material to make it dense.

[0176] 8) Installation of transfer beam 9 and center support frame 10

[0177] Before installation, a total station is used to accurately lay out the lines and accurately determine the plane position. The conversion beam 9 is installed first and then the central support frame 10 is installed. The nodes are welded firmly and reliably according to the node form required by the frame design.

[0178] 9) Fabrication and installation of inner ring truss 1

[0179] To ensure accuracy during the production of the inner ring truss 1, the upper and lower chords are assembled into full circles on the ground, and then hoisted in blocks for assembly on the platform. The docking interfaces of the upper and lower chord steel pipes should be staggered. The assembly sequence is the lower chord tube, the vertical pole, and the upper chord tube of the web member. Before assembly on the platform, an overall installation measurement and layout should be carried out. When laying out the lines, the center point of the component should be marked on the platform, and the positioning line of the overall steel structure should be laid out. The dimensional deviation between each support point is ≤3mm, and the elevation deviation is ≤3mm. The position where the inner ring is connected to the 12 radial trusses 6 is laid out, and the deviation of the embedded bolts at the surrounding supports is checked to see if it meets the design and installation requirements, and then the inner ring truss 1 is accurately positioned.

[0180] 10) Fabrication and installation of radial truss 6

[0181] The prefabrication, assembly and welding of the radial truss 6 is carried out on the membrane. The design and assembly of the membrane adopts the vertical assembly method. First, the upper and lower chord members are installed on the plane, and the plane geometry is measured and fixed. Auxiliary positioning can be used. In order to ensure the positioning of the upper and lower chords with the corresponding side columns and inner ring trusses, temporary vertical rods are added at both ends to control the size between the upper and lower chords of the truss;

[0182] When welding, attention should be paid to the welding sequence to prevent out-of-plane deformation and excessive deformation of the truss sagittal height. The dimensions between the two ends of the radial truss 6 at the three-ring truss position should be strictly controlled to ensure the consistency of the shape between the petals. When welding the truss, first weld the butt weld of the lower chord to ensure that the truss arch is a positive value; then weld the butt weld of the upper chord, then weld the lower chord web, and finally weld the web nodes between the upper chords;

[0183] The two ends of the same web should not be welded at the same time: the welding of the branch pipe and the main pipe should be welded first at the lower chord node weld and then at the upper chord node weld; the two ends of the same web should not be welded at the same time, and the other end should be welded after one end is welded and cooled. For KK and KT type nodes where the chord and the web are connected, the staggered welding method is used to reduce stress concentration;

[0184] After the node welds are welded, the welds shall be inspected according to the design requirements. Unqualified welds shall be repaired and welded properly. After the repair welding is completed, re-inspection shall be carried out;

[0185] The installation sequence of the radial truss 6 should be symmetrical. Before installation, install the columns with support posts of the truss first, and use temporary diagonal rods to support it to achieve stability. When installing a single radial truss 6, support the radial truss support frame 11 in the middle, accurately position one end of the radial truss 6 with the upper and lower chords of the inner ring truss 1, and the other end with the column with support posts. After they are welded reliably, the crane can be used to release the hook. When installing the two-ring truss 2, the three-ring truss 3, the four-ring truss 4, and the outer ring truss 5, pay attention to the plane size and position deviation ≤3mm to avoid strong pulling and pulling to generate secondary stress.

[0186] 11) Twelve sets of "small petals" radial support rods 13

[0187] After the unloading is completed, twelve groups of "small petal" radial support rods 13 are assembled and welded in sequence on the formed integral roof truss structure using a high-altitude bulk method.

[0188] 12) Truss unloading

[0189] During unloading, the radial truss support frame 11 of the radial truss 6 is unloaded first, and then the central support frame 10 is unloaded. The radial truss support frame 11 adopts a symmetrical unloading method, and the central support frame 10 is unloaded by a multiple synchronous unloading method.

[0190] 13) Deflection detection

[0191] Test four points at the cross diameter position, the middle point of the lower chord of the arc-shaped radial truss 6 and the corresponding lower chord point of the inner ring truss 1. The tested deflection value should not be greater than the corresponding deflection value provided by the design.

[0192] 14) Touch-up and topcoat spraying

[0193] The re-coating of welding parts must be carried out in layers according to the original coating requirements, and the topcoat can be applied after acceptance. The coating should be applied evenly, with consistent color, and no pinholes, pores or dripping should appear on the surface. The dry film thickness of the coating should meet the design requirements.

[0194] The above is a clear and complete description of the technical solutions in the embodiments of the present invention. The described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

Claims

1. A circular roof space tube truss structure, characterized in that: It consists of five hoop trusses, twelve radial trusses and twelve groups of radial support rods; The five ring trusses are the inner ring truss, the second ring truss, the third ring truss, the fourth ring truss and the outer ring truss which are concentrically arranged from the inside to the outside. The outer ring truss is supported and fixed by twelve bearings arranged on the top of the surrounding concrete columns. Twelve radial trusses are evenly distributed and installed between five ring trusses in radial shape. The inner end and outer end of each radial truss are connected and installed with the inner ring truss and the outer ring truss respectively, and the part between the inner and outer ends is cross-connected and installed with the second ring truss, the third ring truss and the fourth ring truss respectively; each radial truss is assembled from two pieces of single trusses, and the single trusses are arranged in an arc shape in the plane, and the two pieces of single trusses are assembled in the way of arc joint connection; Twelve groups of radial support rods are evenly distributed and installed radially between the three-ring trusses and the outer ring trusses, and the twelve groups of radial support rods and the twelve radial trusses are arranged in sequence; each group of radial support rods is composed of an upper chord arc rod and a lower chord arc rod with the same structure, and each chord arc rod is assembled from two arc rods, the outer ends of the two arc rods are butt-jointed and fixed to the outer ring truss, and the inner ends are separated and fixed to the three-ring truss.

2. The circular roof space tube truss structure according to claim 1, characterized in that: The upper and lower chords of the inner ring truss are φ500×16, and the upper and lower chords of the other annular trusses are φ168×6; the upper chord of the radial truss is φ325×10, and the lower chord is φ273×14.

3. The construction method of the circular roof space tube truss structure according to claim 1, characterized in that: The steps include: 1) Add steel columns to the mezzanine Four steel columns are added to the top of the concrete columns in the mezzanine facing the center of the circular roof, and the column heads of the steel columns are tightly connected to the top of the floor slab; 2) Support of transfer beam and central support frame The transfer beam is installed at the location where the steel column is set, the central support frame is installed on the transfer beam, and the top layer of the central support frame is laid with a platform plate, as follows: The conversion beam and the central support frame are load-bearing frames composed of a lower structure and an upper structure. The conversion beam is the lower structure, specifically a quadrilateral frame structure formed by four conversion truss beams, with 25mm thick footboards at the four corners, which are installed at the floor position where the steel columns are installed; the central support frame is the upper structure, which is installed on the upper part of the conversion beam. The upper part of the central support frame is a regular hexagonal frame. The circumscribed circle of the regular hexagon is the center line of the inner ring truss. The top layer of the central support frame is paved with a platform plate, and the height of the platform plate is 400mm lower than the lower chord of the inner ring truss. I-beam piers are installed at the six columns outside the regular hexagon to form six support points for supporting the inner ring truss to be installed. 3) Inner ring truss installation First, divide the inner ring truss into four pieces and place them on the ground, then hoist them to the central support frame for assembly and welding, as follows: Before installation, lay out the lines on the platform plate of the center support frame, lay out the center origin and the inner ring plane positioning control line, lay out the node positions of the twelve radial trusses on the platform plate, and support the six columns on the platform plate located outside the center support frame as the support points for the inner ring trusses. The inner ring trusses are assembled on the floor. First, the lower chord ring and the vertical web members and diagonal web members of the inner ring truss are assembled and formed, and then divided into four pieces and hoisted to the center support frame for assembly and welding. Then, the upper chord ring made on the floor is divided into four pieces and hoisted and assembled, and the welding of the connection nodes is completed. 4) Radial truss installation The radial trusses are installed symmetrically, specifically: install the first radial truss, then install the seventh radial truss → install the second radial truss, then install the eighth radial truss → install the third radial truss, then install the ninth radial truss → install the fourth radial truss, then install the tenth radial truss → install the fifth radial truss, then install the eleventh radial truss → install the sixth radial truss, then install the twelfth radial truss; Each radial truss is installed in a piece-by-piece vertical bulk manner, that is, one piece of arc-shaped single truss is installed first, and then the other piece of arc-shaped single truss is installed; the inner end of each radial truss is connected and installed with the inner ring truss, and the outer end is connected and installed with the support set on the top of the surrounding concrete column; after the installation of each radial truss is completed, the second ring truss, the third ring truss, and the fourth ring truss are installed, which are located between the two pieces of arc-shaped single trusses of each radial truss. When installing, the third ring truss in the middle should be installed first, and then the second ring truss and the fourth ring truss on both sides should be installed; When installing the next adjacent radial truss, after one of the arc-shaped mono-trusses of the next radial truss is installed, first install the second ring truss, the third ring truss, the fourth ring truss, and the outer ring truss located between the two adjacent radial trusses. After the installation of the second ring truss, the third ring truss, the fourth ring truss, and the outer ring truss are installed. After the installation of the second ring truss, the third ring truss, and the fourth ring truss are installed between the two arc-shaped mono-trusses. This process is repeated to complete the installation of all radial trusses in the circumference. During the installation of the radial truss, a radial truss support frame is provided in the middle support thereof; 5) Unloading of support frame Install and weld according to the above process sequence and method, and unload after completion; the unloading is divided into two parts, the first part is the unloading of the radial truss support frame, and the second part is the unloading of the central support frame. After all the radial truss support frames are unloaded, the central support frame is unloaded; The unloading of the radial truss support frame is performed by first unloading the first radial truss support frame and the seventh radial truss support frame, and then sequentially unloading the second radial truss support frame and the eighth radial truss support frame, the third radial truss support frame and the ninth radial truss support frame, the fourth radial truss support frame and the tenth radial truss support frame, the fifth radial truss support frame and the eleventh radial truss support frame, the sixth radial truss support frame and the twelfth radial truss support frame; The unloading of the central support frame adopts the stepwise synchronous unloading method. When unloading, a 25t hydraulic jack is used next to each of the six supporting points of the inner ring truss to push up to the lower chord of the inner ring truss, and the I-beam pier is removed. At this time, the six jacks are used for support. The six jacks are controlled to unload synchronously each time, and the unloading height is 10mm each time until the unloading is completed and the structure completes the force conversion; 6) Installation of twelve sets of radial support rods After unloading is completed, twelve groups of radial support rods are assembled and welded in sequence on the integral roof truss structure using the high-altitude bulk method; 7) Support fixation After all structural members are installed, tighten the surrounding support bolts again and secure them firmly. The entire structure is inspected and tested, and the center support frame can be removed after passing the inspection.

4. The construction method of the circular roof space tube truss structure according to claim 3 is characterized in that: The height of the steel column is 4cm lower than the net height of the mezzanine. After the steel column is in place, four jacks are used to tighten the column head to the floor slab, and inclined pads are added around the column base. After removing the jacks, a 600*600 side formwork is supported and C60 high-strength non-shrinkage grouting material is poured from one end to fill the gap at the bottom of the column tightly.

5. The construction method of the circular roof space tube truss structure according to claim 3 is characterized by: The central support frame includes seven vertically arranged main support steel columns, six of which are evenly distributed along a circle of the inner ring truss, and the remaining main support steel column is distributed along the center of the inner ring truss. Horizontal rods are connected and fixed between adjacent main support steel columns. The platform plate on the top of the central support frame is 12mm thick. Jacks are set on the platform plate to fine-tune the position of the assembled inner ring truss. During adjustment, two people raise the jacks synchronously and prepare steel plates of different thicknesses for adjustment. After adjustment and verification, the steel plates are welded and fixed.

6. The construction method of the circular roof space tube truss structure according to claim 3 is characterized by: When the first radial truss is installed, four guy ropes are used for temporary tensioning to prevent it from tipping over. When the first arc-shaped single truss of the adjacent second radial truss is not tensioned with the first radial truss, the tower crane is connected to the annular truss without releasing the hook.

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