Construction method of super-large-diameter full-pin-shaft connection transfer truss

Abstract

The invention discloses a construction method for a super-large-diameter full-pin-shaft connection conversion truss. The construction method comprises the following steps that 1, a supporting system and an operation platform are designed; 2, an installation sequence is formulated according to a finite element analysis result, so that the whole transfer truss is completed in place according to the original elevation; the method specifically comprises the following steps that 2.1, a lower chord member is installed; 2.2, a lower chord three-pin-shaft joint is installed; step 2.3, mounting a middle lower chord member; 2.4, mounting a lower chord web member; 2.5, a diagonal web member operation platform is installed; 2.6, upper chord diagonal web members are installed; step 2.7, mounting an upper chord member; (2.8) two pin shaft nodes of the upper chord are installed; step 2.9, mounting diagonal web members in the middle of the upper chord; step 2.10, folding the truss; 3, after the trusses are folded, construction of the super-large-diameter full-pin-shaft connection conversion truss is completed; according to the invention, partial high-altitude operation can be avoided, the mounting precision is improved, and meanwhile, the construction cost of high-altitude temporary supporting and high-altitude hoisting is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of steel structure building engineering, and in particular to a construction method for an ultra-large diameter full-pin-shaft connected conversion truss. Background Art

[0002] With the development of the construction industry, the application of super high-rise steel structure projects has become increasingly widespread. With the advancement of construction technology, the conversion trusses with full pin connections have gradually been used in super high-rise structures. Since the conversion trusses with full pin connections involve high-altitude loose assembly and high-altitude shaft penetration, and the truss nodes are generally heavy and require high installation accuracy, the above construction difficulties will lead to difficulties in on-site installation and high safety risks. In addition, in the existing technology, no construction method using super large diameter full pin connection conversion trusses has been found. For example, a Chinese patent with publication number CN 117552527 A discloses a method for installing a large-span truss rectangular cross-section web member without adding any gaps, the steps of which are as follows: installing a support frame and installing a lower chord beam on the support frame, and installing a lower cross bar connecting beam between the two lower chord beams; pre-assembling an upper chord beam and an inclined web member on the working surface, and assembling the upper chord beam and the two inclined web members into a K-shaped unit; synchronously installing a K-shaped unit on the two lower chord beams and welding the K-shaped unit to the lower chord beam; installing an upper cross bar connecting beam between the two K-shaped units to connect the two K-shaped units into a whole; welding and fixing the upper chord beam of the K-shaped unit to the position to be fixed; and completing the construction of all sections one by one. This patent is a construction method for large-span truss rectangular cross-section web members, and does not involve a construction method for trusses using full pin connection; publication number CN Chinese Patent No. 113833107A discloses a welding method for a conversion truss and its truss nodes, a conversion truss, comprising: steel columns, chords, diagonal webs and truss nodes, the conversion truss as a whole presents a square frame structure with upper and lower openings, the steel columns, chords and diagonal webs are connected through truss nodes, the steel columns include Japanese-shaped columns and box-shaped columns, the steel columns are all vertically arranged, and the chords are all horizontally arranged; this patent is an improvement on the conversion truss, and does not involve the truss adopting a full pin shaft connection method.

[0003] Therefore, a construction method of an ultra-large diameter full pin-connected conversion truss is provided to solve the above technical problems. Summary of the invention

[0004] The purpose of the invention is to provide a construction method for an ultra-large diameter full pin-shaft connection conversion truss.

[0005] The object of the present invention is achieved in that: A construction method for an ultra-large diameter all-pin-connected conversion truss comprises the following steps: Step 1: Design a support system and operating platform based on actual needs to provide support for subsequent operations; Step 2: According to the results of finite element analysis, formulate the installation sequence so that the entire conversion truss can be completed in place according to the original elevation; the details are as follows: Step 2.1: Install the lower chord; Step 2.2: Install the three-pin node of the lower chord; Step 2.3: Install the middle lower chord; Step 2.4: Install the lower chord web member; Step 2.5: Install the diagonal web member operating platform; Step 2.6: Install the upper chord diagonal web member; Step 2.7: Install the upper chord; Step 2.8: Install the two-pin node of the upper chord. First, install the lattice support, and then assemble the upper chord node and the diagonal web member on the ground. After the pins are installed, hoist the entire truss to the installation site, as follows: 2.8.1. Slowly raise the upper chord two pin nodes of the tower crane, align them with the web lugs, and adjust the angles. Slowly insert the upper chord lug into the belly bar lug.

[0006] 2.8.2. Install the pin hanger. Install the pin hanger on the upper chord. Use a small hand chain hoist to connect the fixed ring and pin to the pin hanger. The hand chain hoist also has the function of adjusting the pin angle. 2.8.3. Apply lubricant to the pin and pin hole to reduce the friction resistance during the traction process; 2.8.4. Install the traction screw. After confirming that the pin shaft hole is concentric, screw the M30 traction screw into the reserved inner thread opening in the center of the pin shaft. Install the pad, fixing plate, backing plate and nut in sequence. During the installation of the traction screw, control the time to avoid the pin shaft hole from being offset again. 2.8.5. Pull the pin in and pull the pin, pin guide plate and traction screw to one end synchronously by screwing the nut of the traction screw. As the pin is inserted, remove the lifting ring near the node side. 2.8.6. Pull the pin into place and pull the pin to the designed position by continuously tightening the nut; 2.8.7. Install the belly bar fall chain and install a hand chain hoist at the end of the belly bar, with the other end connected to the wire rope to assist in adjusting the belly bar angle; 2.8.8. For overall hoisting, slowly lift the hook, and when the web gradually leaves the ground, slowly adjust the fall chain to make the web angle gradually approach the design angle; 2.8.9. Lift the combined components to the predetermined position, slowly loosen the chain, and adjust the Angle the rod until the docking port is flush; 2.8.10. Fixing and adjustment: After the web bar is adjusted, it is temporarily fixed with a code plate. The jack is used to fine-tune the upper chord rod; after the coordinates are adjusted, the code plate is temporarily welded and fixed; 2.8.11. Butt welding: After the coordinates of the components are adjusted, the web and chord welding operations are carried out; Step 2.9 Install the diagonal brace in the middle of the upper chord and use a shoulder pole to hoist the diagonal brace to the predetermined location, as follows: 2.9.1. In the ground stage, according to the construction plan, the shoulder pole beam is processed in advance. The cross section of the shoulder pole beam is HW250X250X9X14, length 2.0m, quantity 2; apply lubricant to the pin and pin hole to reduce the friction resistance during traction; 2.9.2. For overall hoisting, slowly lift the hook, and when the web gradually leaves the ground, slowly adjust the fall chain to make the web angle gradually approach the design angle; 2.9.3. Install the operating hanging basket on both sides of the upper chord pin hole. The height of the hanging basket is 2.7m, the width is 1.2m, and the cross section of the main limb is L50*3; 2.9.4. Hoist the web into place. Hoist the web as a whole to the predetermined position. Use a tower crane to slowly insert the web ear plate into the upper chord ear plate. Use a jack and a crowbar to make fine adjustments to align the center of the pin shaft hole. 2.9.5. Install the traction screw. After confirming that the pin shaft hole is concentric, screw the M30 traction screw into the reserved inner thread hole in the center of the pin shaft. Install the pad, fixing plate, backing plate and nut in sequence. During the installation of the traction screw, control the time to avoid the pin shaft hole from being offset again. 2.9.6. Pull the pin in and tighten the nut of the pull screw to pull the pin, pin guide plate and pull screw to one end simultaneously. As the pin is inserted, remove the lifting ring near the node side. 2.9.7. Pull the pin into place and pull the pin to the designed position by continuously tightening the nut; 2.9.8. Adjust the hoist. After the pin is installed, adjust the hand chain hoist to adjust the angle of the belly bar until the belly bar is flush with the interface; 2.9.9. Fix the yard plate and temporarily fix the yard plate welded at the interface of the web bar; 2.9.10. Butt welding: After the code plate is temporarily fixed, the web butt welding is carried out.

[0007] Step 2.10: Close the trusses and install the middle upper chord and support; Step 3: After the trusses are closed, the construction of the extra-large diameter full pin-connected conversion truss is completed.

[0008] In the step 2, the truss is installed and arched by using the three-pin node of the lower chord and the two-pin node of the upper chord for overall arching. The arching of the lower chord of the truss is installed in combination with the standard layer construction. The three-pin node of the lower chord is connected to the suspension column by a pin. The key to the arching of the lower chord of the truss is that the elevation of the pin hole of the suspension column reaches the arching position. When the suspension column is installed, a temporary support is set at the bottom of the column, and the support height is determined through calculation and analysis to ensure the installation position of the pin hole of the suspension column.

[0009] In the step 2, in combination with the site conditions and the complexity of high-altitude shaft penetration, the ground shaft penetration method is adopted for the second pin shaft node of the upper chord, and the combined component is hoisted as a whole with the web member; first, the web member is hoisted to the assembly area, and the second pin shaft node of the upper chord is slowly lifted by a tower crane and moved to the top of the web member ear plate. This process ensures that the web member and the chord member are on the same surface, and the upper chord member is slowly dropped and inserted into the web member ear plate. The concentricity of the pin shaft hole is adjusted by a crowbar or a jack. After confirming that the pin shaft hole is concentric, butter is applied to the ear plate hole wall and the pin shaft surface.

[0010] In step 2.1, the installation of the lower chord is as follows: first, the lower chords at both ends are installed, and after the pin is installed, one end is placed on a temporary support, and the hook is loosened after being welded and fixed.

[0011] In step 2.2, the installation of the lower chord three-pin node is specifically as follows: before installing the node, a round tube support needs to be set up, and after the lower chord pin is installed, the upper flange of the chord rod and the side chord rod are welded and fixed using a code plate.

[0012] In step 2.3, the installation of the middle lower chord is specifically as follows: after installing the lower chord nodes in sequence, the lower chord of the truss is closed, and the floor steel beam is installed in time after the chord is connected.

[0013] In step 2.4, the installation of the lower chord web member is as follows: after the lower chord is penetrated, the diagonal web member is installed, and after the pin shaft is installed and the coordinates are corrected, a round tube support is used for welding and fixing.

[0014] In step 2.5, the diagonal brace operating platform is installed as follows: after the diagonal brace is installed, the diagonal brace docking interface operating platform is installed.

[0015] In step 2.6, the installation of the upper chord diagonal brace is specifically as follows: first, an operating platform and a pin hanger are installed at the upper chord end of the giant column, and then the installation of the diagonal brace at the end of the giant column begins.

[0016] In step 2.7, the upper chord rod is installed as follows: after the side chord rods are installed, the upper chord rod is installed, and after the pin shaft is installed, one end is placed on the round tube support.

[0017] The beneficial effects of the present invention are as follows: 1. The present invention can avoid some high-altitude operations, improve the installation accuracy, and reduce the construction costs of high-altitude temporary support and high-altitude hoisting; 2. The present invention can improve construction efficiency and shorten the construction period; 3. The present invention can ensure stability and safety during the construction process. The risk of construction accidents is reduced, the lives of construction workers are protected, and construction delays and additional costs caused by accidents are also reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 A schematic diagram of the truss of the present invention being closed; Figure 2 A schematic diagram of installing an intermediate diagonal web node of the present invention; Figure 3 It is a schematic diagram of installing the upper chord two-pin node of the present invention; Figure 4 A schematic diagram of installing the upper chord at the end of a giant column according to the present invention; Figure 5 It is a schematic diagram of installing the diagonal brace at the end of a giant column according to the present invention; Figure 6 A schematic diagram of installing a temporary support for the upper chord according to the present invention; Figure 7 A schematic diagram of installing a diagonal brace according to the present invention; Figure 8 A schematic diagram of installing the middle lower chord of the present invention; Fig. 9 This is a schematic diagram of the lower chord tripod node of the present invention; Fig.10 This is a schematic diagram of installing the lower chord at the end of the giant column according to the present invention; Fig.11 A schematic diagram of temporary support for the installation of the lower chord rod of the present invention; Figures 12 to 25 It is the on-site construction drawing of the present invention. DETAILED DESCRIPTION

[0019] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0020] A construction method for an ultra-large diameter all-pin-connected conversion truss, such as Figures 1 to 11 As shown, the following steps are included: Step 1: Design a support system and operating platform based on actual needs to provide support for subsequent operations; First, conduct a construction analysis of the truss structure, and design the layout and configuration of the support system according to the truss construction sequence. Consider the location, spacing, and connection method of the support points to ensure that the support system can effectively support the truss structure and prevent it from deformation or instability. Determine the installation sequence and location of the support system according to the design requirements and construction sequence. Use measuring instruments to locate and ensure the accuracy and precision of the support points. After the installation is completed, adjust and calibrate the temporary support. Use measuring instruments to check the verticality of the support system to ensure that it meets the requirements of the specifications. And conduct a comprehensive safety inspection to check whether the connection is firm, whether the support materials are damaged or deformed, and whether the support system is stable.

[0021] The operating platform is a key link to ensure the safety and efficiency of aerial work. During the design and installation process, relevant safety specifications and standards should be strictly followed to ensure the structural safety and functional perfection of the platform. According to the truss operation requirements and the component installation sequence, the operating platform can be personalized to meet special work requirements.

[0022] Stability is the primary consideration in the design of an operating platform. Its load capacity should be accurately calculated and designed to ensure that it can withstand the predetermined load during operation and prevent safety accidents caused by overloading.

[0023] The installation process must be carried out step by step in strict accordance with the design drawings and construction sequence. After the installation is completed, the operating platform should be inspected and accepted. Check whether the main force points are welded and whether the platform is stable.

[0024] Step 2: According to the finite element analysis results, formulate the installation sequence so that the entire conversion truss can be completed in place according to the original elevation; the details are as follows: Step 2.1, install the lower chord; the details are as follows: first install the lower chords at both ends. After the pin is installed, place one end on a temporary support, weld it and then loosen the hook.

[0025] Step 2.2, install the lower chord three-pin node; the details are as follows: before installing the node, it is necessary to set up a round tube support. After the lower chord pin is installed, use a code plate to weld the upper flange of the chord and the side chord to fix it.

[0026] Step 2.3, install the middle lower chord; the details are as follows: after installing the lower chord nodes in sequence, close the lower chord of the truss, and install the floor steel beam in time after the chord is connected.

[0027] Step 2.4, install the lower chord web member; the details are as follows: after the lower chord is connected, start installing the diagonal web member, and after the pin shaft is installed and the coordinates are corrected, use round tube supports to weld and fix them.

[0028] Step 2.5, install the diagonal brace operating platform; the details are as follows: after the diagonal brace is installed, start installing the diagonal brace interface operating platform.

[0029] Step 2.6, install the upper chord diagonal brace; the details are as follows: first install the operating platform and pin hanger at the upper chord end of the giant column, and then start installing the diagonal brace at the end of the giant column.

[0030] Step 2.7, install the upper chord; the details are as follows: after the side chord is installed, start installing the upper chord, and after the pin is installed, place one end on the round tube support.

[0031] Step 2.8: Install the upper chord two-pin node. First install the lattice support. Then assemble the upper chord node and the diagonal web on the ground. After the pin is installed, hoist the entire structure to the installation site. 2.8.1: Slowly lift the upper chord two-pin node with the tower crane, align it with the web ear plate, and adjust the angle. Slowly insert the upper string lug into the belly bar lug; 2.8.2. Install the pin hanger. Install the pin hanger at the upper chord. Use a small hand chain hoist to connect the fixing ring and the pin to the pin hanger. The hand chain hoist also has the function of adjusting the pin angle.

[0032] 2.8.3. Apply lubricant to the pin and pin hole to reduce the friction resistance during the traction process.

[0033] 2.8.4. Install the traction screw. After confirming that the pin shaft hole is concentric, screw the M30 traction screw into the reserved inner thread opening in the center of the pin shaft. Install the spacer, fixing plate, backing plate and nut in sequence. During the installation of the traction screw, control the time to avoid the pin shaft hole from being offset again.

[0034] 2.8.5. Pull the pin in and pull the pin, pin guide plate and traction screw to one end simultaneously by turning the nut of the traction screw. As the pin is inserted, remove the lifting ring near the node side.

[0035] 2.8.6. Pull the pin into place and pull the pin to the designed position by continuously tightening the nut.

[0036] 2.8.7. Install the belly bar fall chain and install a hand winch at the end of the belly bar, with the other end connected to the wire rope to assist in adjusting the belly bar angle.

[0037] 2.8.8. Lift the whole structure and slowly lift the hook. When the belly bar gradually leaves the ground, slowly adjust the fall chain to make the belly bar angle gradually approach the design angle.

[0038] 2.8.9. Lift the combined components to the predetermined position, slowly loosen the chain, and adjust the Angle the rod until the butt joint is flush.

[0039] 2.8.10. Fixing and adjustment: After the web bar is adjusted, it is temporarily fixed with a code plate. The jack is used to make fine adjustments to the upper chord; after the coordinates are adjusted, a code plate is used to temporarily weld and fix them.

[0040] 2.8.11. Butt welding: After the coordinates of the components are adjusted, the web and chord welding operations are carried out.

[0041] Step 2.9: Install the middle diagonal brace of the upper chord and use a shoulder pole to lift the diagonal brace to the designated location.

[0042] 2.9.1. In the ground stage, according to the construction plan, the shoulder pole beam is processed in advance. The cross section of the shoulder pole beam is HW250X250X9X14, length 2.0m, quantity 2; apply lubricant to the pin shaft and pin shaft hole to reduce the friction resistance during the traction process.

[0043] 2.9.2. Lift the whole structure and slowly lift the hook. When the web gradually leaves the ground, slowly adjust the fall chain to make the web angle gradually approach the design angle.

[0044] 2.9.3. Install the operating hanging basket on both sides of the upper chord pin hole. The height of the hanging basket is 2.7m, the width is 1.2m, and the cross-section of the main limb is L50*3.

[0045] 2.9.4. Lift the web into place. Lift the web as a whole to the predetermined position. Use a tower crane to slowly insert the web ear plate into the upper chord ear plate. Use a jack and a crowbar to make fine adjustments to align the centers of the pin shaft holes.

[0046] 2.9.5. Install the traction screw. After confirming that the pin shaft hole is concentric, screw the M30 traction screw into the reserved inner thread opening in the center of the pin shaft. Install the spacer, fixing plate, backing plate and nut in sequence. During the installation of the traction screw, control the time to avoid the pin shaft hole from being offset again.

[0047] 2.9.6. Pull the pin in and, by tightening the nut of the pulling screw, pull the pin, pin guide plate and pulling screw to one end simultaneously. As the pin is inserted, remove the lifting ring near the node side.

[0048] 2.9.7. Pull the pin into place and pull the pin to the designed position by continuously tightening the nut.

[0049] 2.9.8. Adjust the hoist. After the pin is installed, adjust the hand chain hoist to adjust the angle of the belly bar until the belly bar is flush with the interface.

[0050] 2.9.9. Fix the yard plate and weld the yard plate temporarily at the interface of the belly bar.

[0051] 2.9.10. Butt welding: After the code plate is temporarily fixed, the web butt welding is carried out.

[0052] Step 2.10 Close the trusses and install the middle upper chord and support.

[0053] In the step 2, the truss is installed and arched by using the three-pin node of the lower chord and the two-pin node of the upper chord for overall arching. The arching of the lower chord of the truss is installed in combination with the standard layer construction. The three-pin node of the lower chord is connected to the suspension column by a pin. The key to the arching of the lower chord of the truss is that the elevation of the pin hole of the suspension column reaches the arching position. When the suspension column is installed, a temporary support is set at the bottom of the column, and the support height is determined through calculation and analysis to ensure the installation position of the pin hole of the suspension column.

[0054] In the step 2, in combination with the site conditions and the complexity of high-altitude shaft penetration, the ground shaft penetration method is adopted for the second pin shaft node of the upper chord, and the combined component is hoisted as a whole with the web member; first, the web member is hoisted to the assembly area, and the second pin shaft node of the upper chord is slowly lifted by a tower crane and moved to the top of the web member ear plate. This process ensures that the web member and the chord member are on the same surface, and the upper chord member is slowly dropped and inserted into the web member ear plate. The concentricity of the pin shaft hole is adjusted by a crowbar or a jack. After confirming that the pin shaft hole is concentric, butter is applied to the ear plate hole wall and the pin shaft surface.

[0055] Step 3: After the trusses are closed, the construction of the extra-large diameter full pin-connected conversion truss is completed.

[0056] like Figures 12 to 25 As shown in the figure, the upper chord two-pin node adopts the method of ground assembly and overall hoisting. Compared with high-altitude assembly, it saves the cost of temporary tire frames required for the installation of the belly rods, and the tire frames save a total of 20t of raw materials. At the same time, a reasonable construction plan was adopted, which saved part of the construction period and created economic benefits. During the construction of the pin shaft conversion truss, the labor team implemented two shifts. Among them, there were 16 installers and 16 welders in the day shift.

[0057] There are 14 night shift installers and 10 welders. The labor cost of welders is 500 yuan / man-day, and the labor cost of installers is 370 yuan / man-day. The price of steel is 5,900 yuan / ton. The labor cost saving calculation is: 30×370×32+26×500×32=771200 yuan Calculation of tire frame cost: raw material cost + processing and manufacturing cost + installation and removal cost = total cost savings 20×5900+20×2400+20×800=182000 yuan The total savings were RMB 953,200.

Claims

1. A construction method for an ultra-large diameter all-pin-connected conversion truss, characterized in that it comprises the following steps: Step 1: Design a support system and operating platform based on actual needs to provide support for subsequent operations; Step 2: According to the results of finite element analysis, formulate the installation sequence so that the entire conversion truss can be completed in place according to the original elevation; the details are as follows: Step 2.1: Install the lower chord; Step 2.2: Install the three-pin node of the lower chord; Step 2.3: Install the middle lower chord; Step 2.4: Install the lower chord web member; Step 2.5: Install the diagonal web member operating platform; Step 2.6: Install the upper chord diagonal web member; Step 2.7: Install the upper chord; Step 2.8: Install the two-pin node of the upper chord. First, install the lattice support, and then assemble the upper chord node and the diagonal web member on the ground. After the pins are installed, hoist the entire truss to the installation site, as follows: 2.8.

1. Slowly raise the upper chord two pin nodes of the tower crane, align them with the web lugs, and adjust the angles. Slowly insert the upper string lug into the belly bar lug; 2.8.

2. Install the pin hanger. Install the pin hanger on the upper chord. Use a small hand chain hoist to connect the fixed ring and pin to the pin hanger. The hand chain hoist also has the function of adjusting the pin angle. 2.8.

3. Apply lubricant to the pin and pin hole to reduce the friction resistance during the traction process; 2.8.

4. Install the traction screw. After confirming that the pin shaft hole is concentric, screw the traction screw into the reserved inner thread opening in the center of the pin shaft. Install the pad, fixing plate, backing plate and nut in sequence. During the installation of the traction screw, control the time to avoid the pin shaft hole from being offset again. 2.8.

5. Pull the pin in and pull the pin, pin guide plate and traction screw to one end synchronously by screwing the nut of the traction screw. As the pin is inserted, remove the lifting ring near the node side. 2.8.

6. Pull the pin into place and pull the pin to the designed position by continuously tightening the nut; 2.8.

7. Install the belly bar fall chain and install a hand chain hoist at the end of the belly bar, with the other end connected to the wire rope to assist in adjusting the belly bar angle; 2.8.

8. For overall hoisting, slowly lift the hook, and when the web gradually leaves the ground, slowly adjust the fall chain to make the web angle gradually approach the design angle; 2.8.

9. Lift the combined components to the predetermined position, slowly loosen the chain, and adjust the Angle the rod until the docking port is flush; 2.8.

10. Fixing and adjustment: After the web bar is adjusted, it is temporarily fixed with a code plate. The jack is used to fine-tune the upper chord rod; after the coordinates are adjusted, the code plate is temporarily welded and fixed; 2.8.

11. Butt welding: After the coordinates of the components are adjusted, the web and chord welding operations are carried out; Step 2.9 Install the diagonal brace in the middle of the upper chord and use a shoulder pole to hoist the diagonal brace to the predetermined location, as follows: 2.9.

1. In the ground stage, according to the construction plan, the shoulder pole beam is processed in advance. The cross section of the shoulder pole beam is HW250X250X9X14, length 2.0m, quantity 2; apply lubricant to the pin and pin hole to reduce the friction resistance during traction; 2.9.

2. For overall hoisting, slowly lift the hook, and when the web gradually leaves the ground, slowly adjust the fall chain to make the web angle gradually approach the design angle; 2.9.

3. Install the operation hanging basket. Install the hanging basket on both sides of the upper chord pin hole. The height of the hanging basket is 2.7m and the width is 1.2m, the main limb section adopts L50*3; 2.9.

4. Hoist the web into place. Hoist the web as a whole to the predetermined position. Use a tower crane to slowly insert the web ear plate into the upper chord ear plate. Use a jack and a crowbar to make fine adjustments to align the center of the pin shaft hole. 2.9.

5. Install the traction screw. After confirming that the pin shaft hole is concentric, screw the traction screw into the reserved inner thread opening in the center of the pin shaft. Install the pad, fixing plate, backing plate and nut in sequence. During the installation of the traction screw, control the time to avoid the pin shaft hole from being offset again. 2.9.

6. Pull the pin in and tighten the nut of the pull screw to pull the pin, pin guide plate and pull screw to one end simultaneously. As the pin is inserted, remove the lifting ring near the node side. 2.9.

7. Pull the pin into place and pull the pin to the designed position by continuously tightening the nut; 2.9.

8. Adjust the hoist. After the pin is installed, adjust the hand chain hoist to adjust the angle of the belly bar until the belly bar is flush with the interface; 2.9.

9. Fix the yard plate and temporarily fix the yard plate welded at the interface of the web bar; 2.9.

10. Butt welding: After the code plate is temporarily fixed, the web bar butt welding is carried out; Step 2.10: Close the trusses and install the middle upper chord and support; Step 3: After the trusses are closed, the construction of the extra-large diameter full pin-connected conversion truss is completed.

2. The construction method of the super-large diameter all-pin-connected conversion truss according to claim 1 is characterized in that: In the step 2, the truss is installed and arched by using the three-pin node of the lower chord and the two-pin node of the upper chord for overall arching. The arching of the lower chord of the truss is installed in combination with the standard layer construction. The three-pin node of the lower chord is connected to the suspension column by a pin. The key to the arching of the lower chord of the truss is that the elevation of the pin hole of the suspension column reaches the arching position. When the suspension column is installed, a temporary support is set at the bottom of the column, and the support height is determined through calculation and analysis to ensure the installation position of the pin hole of the suspension column.

3. The construction method of the super-large diameter all-pin-connected conversion truss according to claim 1 is characterized in that: In the step 2, in combination with the site conditions and the complexity of high-altitude shaft penetration, the ground shaft penetration method is adopted for the second pin shaft node of the upper chord, and the combined component is hoisted as a whole with the web member; first, the web member is hoisted to the assembly area, and the second pin shaft node of the upper chord is slowly lifted by a tower crane and moved to the top of the web member ear plate. This process ensures that the web member and the chord member are on the same surface, and the upper chord member is slowly dropped and inserted into the web member ear plate. The concentricity of the pin shaft hole is adjusted by a crowbar or a jack. After confirming that the pin shaft hole is concentric, butter is applied to the ear plate hole wall and the pin shaft surface.

4. The method for constructing a super-large diameter all-pin-connected conversion truss according to claim 1, characterized in that: In step 2.1, the installation of the lower chord is as follows: first, the lower chords at both ends are installed, and after the pin is installed, one end is placed on a temporary support, and the hook is loosened after being welded and fixed.

5. The construction method of the super-large diameter all-pin-connected conversion truss according to claim 1 is characterized in that: In step 2.2, the installation of the lower chord three-pin node is specifically as follows: before the node is installed, a round tube support needs to be set up, and after the lower chord pin is installed, a code plate is used to weld and fix the upper flange of the chord rod to the side chord rod.

6. The construction method of the super-large diameter all-pin-connected conversion truss according to claim 1 is characterized in that: In step 2.3, the installation of the middle lower chord is specifically as follows: after installing the lower chord nodes in sequence, the lower chord of the truss is closed, and the floor steel beam is installed in time after the chord is connected.

7. The construction method of the super-large diameter all-pin-connected conversion truss according to claim 1 is characterized in that: In step 2.4, the installation of the lower chord web member is as follows: after the lower chord is penetrated, the diagonal web member is installed, and after the pin shaft is installed and the coordinates are corrected, a round tube support is used for welding and fixing.

8. The construction method of the super-large diameter all-pin-connected conversion truss according to claim 1 is characterized in that: In step 2.5, the diagonal brace operating platform is installed as follows: after the diagonal brace is installed, the diagonal brace docking interface operating platform is installed.

9. The method for constructing a super-large diameter all-pin-connected conversion truss according to claim 1 is characterized in that: In step 2.6, the installation of the upper chord diagonal brace is specifically as follows: first, an operating platform and a pin hanger are installed at the upper chord end of the giant column, and then the installation of the diagonal brace at the end of the giant column begins.

10. The method for constructing a super-large diameter all-pin-connected conversion truss according to claim 1 is characterized in that: In step 2.7, the upper chord rod is installed as follows: after the side chord rods are installed, the upper chord rod is installed, and after the pin shaft is installed, one end is placed on the round tube support.

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