Overall lifting construction method for multi-layer grid structure

Abstract

The present invention belongs to the technical field of building construction, and discloses a construction method for integral lifting of a multi-layer grid. The method includes: integrally assembling the roof grid in place on the ground; arranging a plurality of concrete columns at intervals along the periphery of the roof grid, installing a lifting bracket as the upper lifting point for lifting on the top of a part of the concrete columns, and installing a hydraulic device on the lifting bracket; respectively connecting each lower lifting point on the roof grid to each hydraulic device, and integrally and locally lifting the roof grid to a preset installation height; dividing the catwalk into a plurality of catwalk installation unit blocks, connecting the upper end of each catwalk installation unit block to the node ball at the corresponding spherical node of the catwalk installation position of the roof grid until the overall installation of the catwalk is completed; and then integrally lifting the roof grid and the catwalk to the designed height. The present invention can improve the construction efficiency, ensure the construction accuracy, reduce the construction safety risk, and is suitable for popularization and use.

Description

Technical Field

[0001] The present invention relates to the technical field of building construction. More specifically, the present invention relates to a construction method for integral lifting of a multi-layer grid. Background Art

[0002] With the continuous development of building technology, large-span roof grid structures have been widely used in large public buildings such as stadiums, exhibition halls, and airport terminals. Traditional construction methods for integral lifting of multi-layer grids usually adopt the methods of segmental hoisting or high-altitude bulk assembly, which have problems such as long construction periods, large safety hazards, and difficult precision control. Especially for the installation of catwalks, traditional methods often require a large amount of welding work at high altitudes, increasing the construction difficulty and risk. Therefore, there is an urgent need for an efficient and safe construction method for integral lifting of multi-layer grids to solve the deficiencies in the prior art. Summary of the Invention

[0003] An object of an embodiment of the present invention is to solve at least the above problems and / or deficiencies and provide at least the advantages described hereinafter.

[0004] Another object of the present invention is to provide a construction method for integral lifting of a multi-layer grid. The present invention realizes efficient and safe construction by integrally assembling the roof grid in-situ on the ground, adopting the integral lifting technology, and combining the modular installation of the catwalk.

[0005] One of the technical problems solved by the present invention: Traditional construction methods for integral lifting of multi-layer grids may have problems such as low construction efficiency and high risks of high-altitude operations. The construction method for integral lifting of multi-layer grids proposed by the present invention first integrally assembles the roof grid in-situ on the ground, and then lifts it in stages through hydraulic lifting equipment, combined with the installation of the catwalk in unit blocks, reducing the difficulty of high-altitude operations, improving the construction efficiency, and at the same time ensuring the accuracy and safety of the installation of the roof grid and the catwalk.

[0006] One of the technical problems solved by the present invention: During the construction process of the roof grid, adverse weather such as strong winds may affect its stability and increase the construction risk. The present invention enhances the stability of the roof grid and ensures construction safety by setting up temporary member balls, wind speed sensors, telescopic support members, and protection controllers to monitor the wind speed in real time and automatically adjust the support members when the wind speed exceeds the threshold value.

[0007] For this reason, the technical solution provided by the present invention is as follows:

[0008] A construction method for integral lifting of a multi-layer grid, comprising:

[0009] 1) Assemble the roof grid in-situ on the ground as a whole; 2) Set multiple concrete columns at intervals along the perimeter of the roof grid. Install a lifting bracket on the top of some of the concrete columns as the upper lifting point for lifting. Install hydraulic devices on the lifting brackets, and set pulling points on the concrete columns where the upper lifting points are set; 3) Connect each lower lifting point on the roof grid to each hydraulic device respectively, and lift the roof grid as a whole to a preset installation height; 4) Divide the catwalk into multiple catwalk installation unit blocks. Transport the assembled catwalk installation unit blocks to the ground below the hoisting position, conduct vertical hoisting. After lifting to the installation position, connect the upper end of the catwalk installation unit block to the node ball at the corresponding spherical node of the catwalk installation position on the roof grid until the whole installation of the catwalk is completed; 5) After installing the catwalk, lift the roof grid and the catwalk as a whole to the designed height.

[0010] Preferably, in the overall lifting construction method of the multi-layer grid, the projection plane of the roof grid is circular, the upper chord surface is spherical, the lower chord surface is a spherical surface similar to a horizontal center, the node connection form is welded spherical node, the structural form is a square pyramid grid, a plurality of two-way elastic spherical hinge supports are arranged around the roof grid, the support form is the lower chord column point, and the lower structure is a concrete frame;

[0011] The overall in-situ assembly of the roof grid on the ground includes the following steps:

[0012] Scaffold erection and lower chord ball installation: Erect the grid assembly scaffold. The scaffold uses steel pipes to support the lower chord balls of the grid, which are welded to the steel plates. The horizontal direction uses steel pipes, and the diagonal rods use angle steels to be connected into a whole;

[0013] Install the lower chord balls on the scaffold and weld them to the node balls;

[0014] Install the upper chord balls, adjust the elevation of the upper chord balls, install the diagonal web members and weld them to the node balls, install the upper chord members, and weld them to the node balls to form a whole;

[0015] Install the purlins to complete the overall assembly of the roof grid.

[0016] Preferably, in the overall lifting construction method of the multi-layer grid, the catwalk is an eccentric catwalk,

[0017] During the hoisting process of the eccentric catwalk, the lifting force provided by each hydraulic device is calculated by the following method:

[0018] F1 = k×G×L2 / (L1 + L2)

[0019] F2 = k×G×L1 / (L1 + L2)

[0020] Among them, F1 is the lifting force of the hydraulic actuator on the side close to the centroid, F2 is the lifting force of the hydraulic actuator on the side far from the centroid, G is the total gravity of the eccentric catwalk, L1 is the horizontal distance from the centroid of the eccentric catwalk to the nearest support point, L2 is the horizontal distance from the centroid of the eccentric catwalk to the farthest support point, and k is the dynamic load coefficient during the lifting process;

[0021] Among them, the determination methods for the side close to the centroid and the side far from the centroid are as follows:

[0022] a) In the ground pre-assembly stage, determine the geometric centroid position of the eccentric catwalk by the weighing method or three-dimensional modeling calculation, and mark the centroid projection point on the catwalk;

[0023] b) According to the design drawing of the eccentric catwalk, determine its structural eccentricity direction;

[0024] c) During hoisting, taking the centroid projection point of the eccentric catwalk as the reference, measure the horizontal distance between the support point corresponding to each hydraulic actuator and the centroid projection point: if the horizontal distance from a certain support point to the centroid projection point is less than or equal to that of other support points, the hydraulic actuator corresponding to this support point is on the side close to the centroid; if the horizontal distance from a certain support point to the centroid projection point is greater than that of other support points, the hydraulic actuator corresponding to this support point is on the side far from the centroid;

[0025] d) When there are multiple support points with equal distances, use the structural eccentricity direction as the determination basis.

[0026] Preferably, in the overall lifting construction method of the multi-layer grid, temporary member balls are provided on the roof grid. The temporary member balls are wrapped outside the temporary joint balls or on the upper chord members. The temporary member balls are arranged at the joints of the members of the roof grid. Among them, a horizontally telescopic support member is provided inside the temporary member ball close to the concrete column. A wind speed sensor is provided on the concrete column. Both the wind speed sensor and the support member are communicatively connected to a protection controller. The wind speed sensor detects the current wind speed in real time and transmits the wind speed data to the protection controller. The protection controller receives the current wind speed data and compares it with a preset wind speed threshold. If the current wind speed data exceeds the preset wind speed threshold, the protection controller controls the support member to telescopically extend horizontally until the distance between it and the concrete column does not exceed 1 centimeter. A displacement sensor is provided at the free end of the support member. The displacement sensor is used to detect the distance between the free end of the support member and the concrete column. The displacement sensor is communicatively connected to the protection controller.

[0027] Preferably, in the method for overall lifting construction of the multi-layer grid structure, in step 3), the overall lifting of the roof grid structure further includes: connecting the hydraulic devices to the hydraulic pump source and both being connected to the synchronous control system, connecting the suspension points of the roof grid structure to the hydraulic devices through steel strands, gradually loading the hydraulic pump pressure in sequence at 20%, 40%, 60%, 80%, and 100% until the roof grid structure is lifted a certain distance above the ground, staying for a period of time, and then proceeding with the lifting;

[0028] During the lifting process, measure each suspension point every several meters of lifting, perform single-point fine-tuning based on the measurement results to make each suspension point lift synchronously. When it is lifted to 1 m away from the designed position, perform fine-tuning on each suspension point and then lift it integrally to the designed position. Among them, stick a reflective sticker on the bottom of the temporary construction ball and mark a "cross", and use a total station for measurement, which facilitates the measurement operation at high altitude.

[0029] Preferably, in the method for overall lifting construction of the multi-layer grid structure, in step 4), the installation method of the catwalk includes: dividing the catwalk into multiple catwalk installation unit blocks, installing the 2 joists between the 4 suspension rods arranged vertically in each unit block on the lower support plates of the suspension rods on the ground, installing the catwalk platform plate on the two joists, placing the two ends of the support beams on both sides of the bottom of the catwalk platform plate on the welded steel plates on the two joists respectively, welding the two ends of the channel steel or rectangular pipe of the support beams on both sides of the bottom of the catwalk platform plate to the steel plates, then installing the railings on both sides of the catwalk above it, connecting the upper ends of the 4 suspension rods of the catwalk installation unit block to the corresponding spherical joints of the catwalk installation position of the roof grid structure. After the installation of the catwalk installation unit block between adjacent suspension rods is completed, supplement and install the platform plate and railing of one span between them and connect them to the adjacent joists, and install them in this order until the overall installation of the catwalk is completed.

[0030] Preferably, in the method for overall lifting construction of the multi-layer grid structure, during the assembly process of the roof grid structure: adopt the ground pattern method to conduct preliminary lofting of the plane positions of the spherical joints, and the positioning sequence is: first the lower chord balls, then the lower chord members, then the vertical web members and the upper chord balls, and finally the upper chord members and the diagonal web members; after the spherical joints are positioned and welded, perform temporary fixation, and recheck the coordinates after welding is completed; divide the assembly area and control the assembly accuracy piece by piece; set assembly control key points at the spherical joints on the outermost side of the assembly unit.

[0031] Preferably, in the method for overall lifting construction of the multi-layer grid structure, during the lifting process of the roof grid structure, hang a tape measure below the lower suspension points, mark the elevation of the center of the spherical joint at each lower suspension point on the side of the adjacent column, visually reflect the height increment of each lifting point through the tape measure, and compare it with the lifting values of each point on the lifting operation interface.

[0032] Preferably, in the overall lifting construction method of the multi-layer grid structure, in step 3), the lifting force of the hydraulic jack is dynamically adjusted by the following method: install a pressure sensor on each hydraulic jack to monitor the lifting force of the hydraulic jack in real time; transmit the data of the pressure sensor to the synchronous control system, and the synchronous control system dynamically adjusts the output pressure of the hydraulic pump according to the difference in the lifting force of each hydraulic jack; if the lifting force of a certain hydraulic jack exceeds the preset threshold, the synchronous control system automatically reduces the lifting force of this hydraulic jack and increases the lifting force of other hydraulic jacks. The synchronous control system is also communicatively connected to the protection controller.

[0033] Preferably, in the overall lifting construction method of the multi-layer grid structure, in step 5), after the roof grid structure and the catwalk are integrally lifted to the designed height, the following steps are further included: set up temporary support frames around the roof grid structure, the height of the temporary support frames is adjustable, and they are used to temporarily support the roof grid structure after the lifting is completed; by adjusting the height of the temporary support frames, align the connection points between the roof grid structure and the concrete columns; fix the roof grid structure and the concrete columns to complete the installation.

[0034] The embodiments of the present invention at least include the following beneficial effects:

[0035] In the present invention, the roof grid structure and the catwalk are lifted simultaneously. Compared with the traditional method of only lifting the roof, in the present invention, the overall assembly of the roof grid structure on the ground and the assembly of the catwalk installation unit blocks are carried out, reducing the amount of high-altitude work and greatly improving the construction efficiency.

[0036] In the present invention, by setting up retractable support members and taking wind protection measures, the telescoping of the support rods is controlled by a wind speed sensor and a protection controller. When the wind force reaches a certain level, the device starts to extend the fixing device towards the concrete column. When the device is about 1 centimeter or less (such as 2 mm) away from the main body, it stops, preventing the grid structure from shaking due to excessive wind force. After the wind force drops and stabilizes, it retracts. It can effectively protect the roof grid structure in strong wind weather and reduce the construction safety risk. At the same time, the reasonable construction process and lifting operation also reduce the potential safety hazards during the construction process.

[0037] In the process of assembling and lifting the roof grid structure of the present invention, a variety of precision control measures are adopted, such as lofting by the ground pattern method, coordinate review, lifting point measurement and fine-tuning, etc., which can effectively ensure the construction precision and ensure the stability and safety of the reticulated shell structure.

[0038] The present invention can improve the construction efficiency, reduce the construction safety risk, and ensure the construction precision, and is suitable for popularization and use in the field of building construction. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 It is the layout diagram of the lifting suspension points of the roof grid structure in one of the embodiments of the present invention.

[0040] Figure 2 This is the layout plan of the temporary grid ceiling in one embodiment of the present invention.

[0041] Figure 3 This is the schematic diagram for calculating the tray size in one embodiment of the present invention.

[0042] Figure 4 This is the schematic diagram for arranging hydraulic devices in one embodiment of the present invention.

[0043] Figure 5 This is the preparatory schematic diagram before lifting the roof space frame in one embodiment of the present invention.

[0044] Figure 6 This is the observation schematic diagram when the roof space frame stays 20 cm above the ground for more than 12 hours in one embodiment of the present invention.

[0045] Figure 7 This is the lifting schematic diagram after installing the catwalk in one embodiment of the present invention.

[0046] Figure 8 This is the schematic diagram for lifting the structure to a position 1 m away from the designed height in one embodiment of the present invention.

[0047] Figure 9 This is the schematic diagram for connecting the lifted structure to the support ball part in one embodiment of the present invention. Detailed implementation manners

[0048] The following further elaborates on the present invention in conjunction with the accompanying drawings, so that those skilled in the art can implement it with reference to the description in the specification.

[0049] The present invention provides a construction method for integral lifting of a multi - layer space frame, including:

[0050] 1) Integrally assemble the roof space frame in - situ on the ground; on the ground of the construction site, according to the design drawings and relevant specification requirements, carry out the integral assembly work of the roof space frame. This requires construction personnel to strictly follow the established technological processes and operation standards to ensure accurate connection and installation of each component of the space frame, laying a foundation for the subsequent lifting operation.

[0051] 2) A number of concrete columns are arranged at intervals along the perimeter of the roof grid. A lifting bracket 2 is installed at the top of a part of the concrete columns as the upper lifting point for lifting, and a hydraulic device 3 is installed on the lifting bracket 2. For example, upper lifting points are set on 1 / 3 to 1 / 2 of the concrete columns. These concrete columns with upper lifting points are evenly spaced along the perimeter of the roof grid. These concrete columns have sufficient strength and stability to bear the loads during subsequent lifting. In one embodiment of the present invention, there are always 40 concrete columns, 20 of which are provided with upper lifting points, and the models of the installed hydraulic devices are different. Pulling nodes are provided on the concrete columns with upper lifting points. The installation of the lifting bracket 2 must be firm and reliable to ensure that it can safely support the weight of the hydraulic device 3 and the roof grid. Then, the hydraulic device 3 is installed on the lifting bracket 2, and the model and performance of the hydraulic device 3 should be reasonably selected according to the weight of the roof grid and the lifting requirements.

[0052] 3) Each lower lifting point 1 on the roof grid is respectively connected to each hydraulic device 3 through a steel strand 4, and the whole roof grid is locally lifted to a preset installation height; during the connection process, the firmness and reliability of the connection should be ensured to avoid loosening or falling off during the lifting process. After the connection is completed, start the hydraulic lifting equipment and locally lift the whole roof grid to the preset installation height. During the lifting process, closely monitor the lifting state of the roof grid to ensure its smooth rise. The layout of the lifting points of the roof grid is as Figure 1 shown.

[0053] 4) The catwalk is divided into multiple catwalk installation unit blocks. The assembly work of each unit block is completed on the ground. The assembled catwalk installation unit blocks are transported to the ground below the hoisting position for vertical hoisting. After being lifted to the installation position, the upper end of the catwalk installation unit block is connected to the nodal ball at the corresponding spherical joint of the catwalk installation position on the roof grid. In this way, each catwalk installation unit block is installed in sequence until the whole catwalk is installed. During the catwalk installation process, pay attention to the connection accuracy and stability between each unit block to ensure the overall quality of the catwalk.

[0054] 5) After the catwalk is installed, the roof grid and the catwalk are lifted to the design height as a whole. During the lifting process, continuously monitor the lifting state of the roof grid and the catwalk to ensure that they safely and smoothly reach the design position. After the lifting is completed, carry out necessary fixing and inspection work to ensure the stability and safety of the entire reticulated shell structure.

[0055] In one solution of the present invention, preferably, the projection plane of the roof grid is circular, the upper chord plane is spherical, the lower chord plane is a quasi-spherical surface with a horizontal center, the node connection form is welded spherical joints, the structural form is a four-corner pyramid grid, a number of two-way elastic spherical hinge supports are arranged around the roof grid, the support form is the lower chord column point, and the lower structure is a concrete frame;

[0056] The overall in-situ assembly of the roof grid on the ground includes the following steps:

[0057] Scaffold erection and lower chord ball installation: Erection of the grid assembly scaffold, with the scaffold using steel pipes to support the lower chord balls of the grid, welded to the steel plate, using steel pipes in the horizontal direction and angle steel for the diagonal rods to form an integral whole;

[0058] Install the lower chord balls on the scaffold and weld them to the joint balls; Erection of the grid assembly scaffold is the basis for the entire assembly work. The scaffold uses steel pipes to support the lower chord balls of the grid, and the steel pipes are welded to the steel plate to ensure the stability of the scaffold. In the horizontal direction, steel pipes are used for connection, and angle steel is used for the diagonal rods to form an integral whole, forming a firm support system. Install the lower chord balls accurately on the scaffold and weld them to the joint balls. The welding process should be carried out strictly in accordance with the welding process requirements to ensure the welding quality.

[0059] After the installation of the lower chord balls is completed, carry out the installation of the upper chord balls. During the installation process, carefully adjust the elevation of the upper chord balls to meet the design requirements. Then, install the diagonal web members and weld them to the joint balls, and then install the upper chord members and weld them to the joint balls to form an integral whole. During the welding process, pay attention to controlling the welding deformation to ensure the overall shape and dimensional accuracy of the grid.

[0060] Install the purlins. The installation of the purlins should be carried out in accordance with the design requirements to ensure accurate and firm installation positions. After the installation of the purlins is completed, the overall assembly work of the roof grid is completed.

[0061] During the entire assembly process, operate strictly in accordance with the design drawings and relevant specification requirements. For the connection and welding of each component, conduct strict quality inspections to ensure the overall quality of the roof grid. At the same time, pay attention to the safety management at the construction site to avoid safety accidents.

[0062] In one embodiment of the present invention, preferably, the catwalk is an eccentric catwalk. When designing the construction of the reticulated shell, the specific dimensions and shape of the eccentric catwalk are designed according to the structural characteristics and usage requirements of the roof space frame. The eccentric catwalk is divided into multiple catwalk installation unit blocks to facilitate assembly on the ground and on-site hoisting. The division of each unit block should take into account the lifting capacity of the hoisting equipment and the convenience of transportation. The installation of each unit block of the eccentric catwalk is carried out in sequence. During the installation process, attention should be paid to the curvature and connection accuracy of the eccentric catwalk to ensure accurate connection between each unit block and form a complete ring structure. After the installation of adjacent unit blocks is completed, the platform plates and railings between them are supplemented and installed and connected to the adjacent supporting beams to gradually complete the overall installation of the eccentric catwalk. During the installation of the eccentric catwalk, it should be closely coordinated with the lifting and installation work of the roof space frame. After the local part of the roof space frame is lifted to the preset installation height, the installation work of the catwalk is carried out in a timely manner. After the installation is completed, it is lifted together with the roof space frame to the design height. Throughout the process, it is necessary to ensure the firm connection between the eccentric catwalk and the roof space frame without affecting the overall stability of the roof space frame. After the installation of the eccentric catwalk is completed, a comprehensive inspection and acceptance should be carried out. Check whether the connection parts of the catwalk are firm, whether the railings are installed in place, whether the platform plates are flat, etc. Ensure that the performance indicators of the eccentric catwalk meet the design requirements and relevant safety standards.

[0063] During the hoisting process of the eccentric catwalk, the lifting force provided by each hydraulic actuator is calculated by the following method:

[0064] F1 = k×G×L2 / (L1 + L2)

[0065] F2 = k×G×L1 / (L1 + L2)

[0066] Wherein, F1 is the lifting force of the hydraulic actuator on the side close to the center of gravity, F2 is the lifting force of the hydraulic actuator on the side far from the center of gravity, G is the total gravity of the eccentric catwalk, L1 is the horizontal distance from the center of gravity of the eccentric catwalk to the nearest support point, L2 is the horizontal distance from the center of gravity of the eccentric catwalk to the farthest support point, and k is the dynamic load coefficient during the lifting process;

[0067] Wherein, the determination methods for the side close to the center of gravity and the side far from the center of gravity are as follows:

[0068] a) During the ground pre-assembly stage, the geometric center of gravity position of the eccentric catwalk is determined by the weighing method or three-dimensional modeling calculation, and the center of gravity projection point is marked on the catwalk;

[0069] b) According to the design drawing of the eccentric catwalk, determine its structural eccentricity direction;

[0070] c) During hoisting, taking the center of gravity projection point of the eccentric catwalk as the reference, measure the horizontal distance between the corresponding support points of each hydraulic device and the center of gravity projection point: If the horizontal distance from a certain support point to the center of gravity projection point is less than or equal to that of other support points, the hydraulic device corresponding to this support point is on the side closer to the center of gravity; if the horizontal distance from a certain support point to the center of gravity projection point is greater than that of other support points, the hydraulic device corresponding to this support point is on the side farther from the center of gravity;

[0071] d) When there are multiple support points with equal distances, take the structural eccentricity direction as the judgment basis.

[0072] In one of the embodiments of the present invention, preferably, protective measures are added for the construction of the roof grid to cope with possible strong wind weather and ensure construction safety. As Figure 2 shown, temporary member balls 5 are provided on the roof grid. These temporary member balls 5 are wrapped outside the temporary joint balls or on the upper chord members, and are provided at the joints of the members of the roof grid. After installation, these temporary member balls 5 will be removed. Among them, a horizontally telescopic support member is provided inside the temporary member ball 5 close to the concrete column. A wind speed sensor is installed on the concrete column, and both the wind speed sensor and the support member are communicatively connected to a protection controller. The wind speed sensor can detect the current wind speed in real time and transmit the wind speed data to the protection controller. After receiving the current wind speed data, the protection controller compares it with a preset wind speed threshold. If the current wind speed data exceeds the preset wind speed threshold (such as a wind force of level 6), the protection controller will control the support member to expand and contract horizontally until the distance between it and the concrete column does not exceed 1 centimeter (such as 2 mm). At the same time, a displacement sensor is provided at the free end of the support member. The displacement sensor is used to detect the distance between the free end of the support member and the concrete column and feed back the detection data to the protection controller. The protection controller precisely controls the expansion and contraction of the support member according to the data fed back by the displacement sensor to ensure that the distance between it and the concrete column meets the requirements. Through this protection measure, the stability of the roof grid can be effectively enhanced in strong wind weather, the influence caused by strong wind on the roof grid can be reduced, and the safety and smooth progress of the construction process can be guaranteed.

[0073] In one of the embodiments of the present invention, preferably, in step 3), the hydraulic actuator 3 is connected to the hydraulic pump source, and both are connected to the synchronous control system. Through the synchronous control system, the synchronous operation of each hydraulic actuator 3 can be achieved, ensuring the smooth lifting of the roof grid. The suspension points of the roof grid are connected to the hydraulic actuator 3 through steel strands to ensure the firmness of the connection. Before lifting, the hydraulic pump pressure is gradually loaded to a certain distance above the ground of the roof grid structure in sequence according to 20%, 40%, 60%, 80%, and 100%. The loading process should be slow and stable to avoid excessive impact on the roof grid. After the loading is completed, stay for a period of time to observe the state of the roof grid to ensure its safety and stability. During the lifting process, each suspension point is measured every few meters. By measuring the height and position of each suspension point, the deviation that may occur during the lifting process can be detected in a timely manner. Single-point fine-tuning is performed according to the measurement results to enable the synchronous lifting of each suspension point. When the lifting reaches 1 m away from the design position, more precise fine-tuning is performed on each suspension point to ensure that the roof grid can accurately reach the design position. Finally, the roof grid is lifted as a whole to the design position. Through this step-by-step loading and precisely controlled lifting method, problems such as tilting and shaking of the roof grid during the lifting process can be effectively avoided, ensuring the safety and smooth progress of the lifting process and guaranteeing the installation accuracy of the roof grid.

[0074] In one of the embodiments of the present invention, preferably, in step 4), the installation method of the catwalk includes: dividing the catwalk into multiple catwalk installation unit blocks, installing the 2 joists between the 4 vertical hanger rods of each unit block on the lower support plates of the hanger rods on the ground, installing the catwalk platform plate on the two joists, placing the two ends of the support beams on both sides of the bottom of the catwalk platform plate on the welded steel plates on the two joists respectively, welding the two ends of the channel steel or rectangular tube of the support beams on both sides of the bottom of the catwalk platform plate to the steel plates, then installing the handrails on both sides of the catwalk platform above it, connecting the upper ends of the 4 hanger rods of the catwalk installation unit block to the corresponding spherical nodes of the catwalk installation position of the roof grid. After the installation of the catwalk installation unit block between adjacent hanger rods is completed, install a span of the platform plate and handrails in between and connect them to the adjacent joists, and install them in this order until the overall installation of the catwalk is completed. During the installation process, attention should be paid to the connection quality and overall coordination between each unit block to ensure that the overall performance of the catwalk meets the design requirements.

[0075] In one of the embodiments of the present invention, preferably, during the assembly of the roof grid: the ground pattern method is used for the preliminary lofting of the plane positions of the spherical joints. The positioning sequence is as follows: first the lower chord balls, then the lower chord members, followed by the vertical web members and the upper chord balls, and finally the upper chord members and the diagonal web members. Positioning in this order can ensure the accurate installation position of the spherical joints and lay a good foundation for the subsequent assembly work. After the spherical joints are positioned and welded, they are temporarily fixed, and the coordinates are rechecked after welding is completed. If any deviation is found, it should be adjusted in a timely manner. The assembly area is divided, and the assembly accuracy is controlled piece by piece. Assembly control key points are set at the spherical joints on the outermost side of the assembly unit. During the assembly process, operations should be carried out strictly in accordance with the design requirements and construction specifications to ensure the quality of each assembly unit. Through these methods, the accuracy and quality of the roof grid assembly can be improved, assembly errors can be reduced, and the overall performance of the roof grid can be ensured to meet the design requirements.

[0076] In one of the embodiments of the present invention, preferably, during the lifting of the roof grid, a tape measure is hung below the lower lifting point 1, and the elevation of the center of the spherical joint at each lower lifting point 1 is marked on the side of the adjacent column. The height increment of each lifting point is directly reflected by the tape measure and compared with the lifting values of each point on the lifting operation interface. Through the comparison, deviations that may occur during the lifting process can be discovered in a timely manner. If a large deviation is found, it should be adjusted in a timely manner to ensure that the heights of all lifting points are the same and to ensure the smooth lifting of the roof grid. This monitoring method is simple and intuitive, can effectively monitor the lifting process of the roof grid, discover and solve problems in a timely manner, and ensure the safety and smooth progress of the lifting process.

[0077] In one of the embodiments of the present invention, preferably, in step 3), the lifting force of the hydraulic actuator is dynamically adjusted by the following method: a pressure sensor is installed on each hydraulic actuator to monitor the lifting force of the hydraulic actuator in real time; the data of the pressure sensor is transmitted to the synchronous control system, and the synchronous control system dynamically adjusts the output pressure of the hydraulic pump according to the difference in the lifting forces of each hydraulic actuator; if the lifting force of a certain hydraulic actuator exceeds the preset threshold, the synchronous control system automatically reduces the lifting force of this hydraulic actuator and increases the lifting force of other hydraulic actuators. The synchronous control system is also communicatively connected to the protection controller.

[0078] In one of the embodiments of the present invention, preferably, in step 5), after the roof grid and the catwalk are integrally lifted to the designed height, the following steps are further included: temporary support frames are arranged around the roof grid, and the height of the temporary support frames is adjustable and used for temporarily supporting the roof grid after the lifting is completed; by adjusting the height of the temporary support frames, the connection points between the roof grid and the concrete columns are aligned; the roof grid is fixed to the concrete columns to complete the installation.

[0079] To enable those skilled in the art to better understand the technical solution of the present invention, the following embodiments are provided for further illustration:

[0080] This embodiment provides a construction method for the overall lifting of a multi-layer grid structure, including:

[0081] Integrally assembling the roof grid structure in-situ on the ground - installing lifting devices using concrete columns 2KZ1 (section size 1m×1m, column top elevation +25.55m) - locally lifting the grid structure as a whole to install the mezzanine catwalk - lifting the grid structure as a whole to the designed elevation - using a 200T crawler crane (because the surrounding component positions are far from the outside of the main body and ordinary cranes cannot reach) to scatter and assemble the surrounding components.

[0082] Overall shape and dimensions of the roof grid structure: The overall grid structure presents a "buckled bowl" shape. The projection plane of the grid is circular, the upper chord surface is spherical, and the lower chord surface is a quasi-spherical surface with a horizontal center. The span diameter of the grid is 70.4 meters, the structural height is between 2.46m - 5.5m, and the web members are sloped to form the roof spherical surface to meet the requirements of the shape and water drainage slope. The installation elevation of the grid is 25.550 meters.

[0083] Nodes and members: The node form is a welded hollow spherical node, and the structural form is a four-corner pyramid grid. The grid members are made of Q355B seamless steel pipes, and the node balls are made of Q355B steel plates by stamping and welding. Among them, the maximum thickness of the welded ball is 45mm, and the maximum thickness of the member is 30mm. Except for the butt welds of the members being of grade I, the rest of the welds are designed to be of grade II.

[0084] Supports and bearings: 40 two-way elastic spherical hinge supports are arranged around the grid, and the support form is the lower chord column point, and the lower structure is a concrete frame. The installation height of the two-way elastic spherical hinge support is +25.55m, and the highest elevation of the center point of the grid is +34.5m.

[0085] Fire protection and anti-corrosion: The fire resistance rating of the project is grade I. The fire resistance limit of the load-bearing members of the reticulated shell roof is 1.50 hours. There is no fire resistance requirement for purlins, etc. The fire protection material is of the intumescent type, with a thickness of not less than 3.0mm. The rust removal grade of the steel is not lower than sa21 / 2 level, the surface roughness is 30 - 75μm, and the anti-corrosion coating thickness is 200μm, which is composed of 2 coats of epoxy zinc-rich primer 70μm + 1 coat of epoxy mica iron intermediate paint 60μm + 2 coats of polyurethane topcoat 70μm. The fire protection coating is set inside the topcoat.

[0086] Purlins and roof panels: The primary and secondary purlins are made of Q355B hot-dip galvanized square steel pipes, and the outer roof panel is a 0.9mm thick fluorocarbon spraying (three coats and three baking) standing seam aluminum-magnesium-manganese alloy roof panel of type 65 - 400.

[0087] The flow section is divided into three construction sections: the overall lifting construction section of the grid, the installation of the mezzanine runway, and the high-altitude scattered assembly construction section.

[0088] Construction plan overview

[0089] The welding balls, rods, purlins and other components in the factory are made separately in the form of loose parts and sent to the site by land transportation; a cradle is set up on the ground, and the welding balls, rods and purlins are assembled on the ground, with the center point of the grid circle as the reference, spreading outward circle by circle; after the grid ground assembly is completed, fire retardant coating and topcoat spraying are carried out; the whole is lifted to the installation height of the horseway and mezzanine; the horseway and mezzanine are hoisted and installed in pieces, and fire retardant coating and topcoat spraying are carried out simultaneously. The whole is lifted to the design height, and the grid roof steel structure is installed; after reaching the positioning elevation, the positioning circle is docked at high altitude, and the grid is in place; the lifting equipment is removed; the outer cantilevered and downward-turned part is made in small pieces on the roof, and then hoisted by a crane to dock with the main grid, and finally the horizontal rods connecting the small pieces are installed to complete the entire grid; fire retardant coating and topcoat spraying are applied to the supplementary rods and the outer cantilevered and downward-turned part; roof panel installation.

[0090] Overall construction process: Finished poles and welded balls delivered to site → on-site inspection → overall assembly of grid ground → assembly inspection → on-site fire retardant coating and topcoat spraying → partial lifting → mezzanine and horseway installation → overall lifting → additional poles in place → overall inspection → removal of lifting equipment → installation of cantilevered and downward parts → on-site fire retardant coating and topcoat spraying → roof installation.

[0091] Technical Parameters

[0092] Lifting grid: After the roof grid (including purlin) is assembled on the ground, it is partially lifted to install the mezzanine runway, and then lifted to the designed position as a whole. The weight of the lifting grid is 580t + the weight of the purlin is 103.8t + the weight of the mezzanine runway is 297.7t, and the total lifting weight is about 981t.

[0093] Upgrading major equipment

[0094] In this project, a new type of lifting technology of hydraulic synchronous cumulative lifting was adopted, mainly using the following key technologies and equipment:

[0095] Hydraulic synchronous lifting technology for super-large components; TJJ-1100-ton hydraulic press 3; TJV-60 hydraulic pump source system; YT-1 computer synchronous control system.

[0096] 1) Hydraulic machine 3

[0097] The hydraulic press 3 is a through-core structure, with flexible steel strands as lifting rigging. This project uses hydraulic presses 3 of models TJJ-600 and TJJ-1100, which can meet engineering requirements.

[0098] 2) Hydraulic pump source system

[0099] The hydraulic pump source system provides hydraulic power for the hydraulic actuator 3 and completes corresponding actions under the control of various hydraulic valves. In different engineering applications, the requirements and models of the lifters are different. To improve the versatility and reliability of the hydraulic lifting equipment, the pump source hydraulic system is designed with a modular structure. The number of pump source systems is configured according to the number and model of the lifters, and multiple modules can be combined. Each set of modules takes a set of pump source systems as the core, can independently control a group of hydraulic actuators 3, and can simultaneously expand multiple lifting points to meet the needs of actual lifting projects. In this project, a hydraulic pump source system with a rated power of 60KW is selected.

[0100] 3) Synchronous control system

[0101] The hydraulic synchronous control system consists of a power control system, a power drive system, a computer control system, etc. It mainly completes the following two control functions: the coordinated control of the actions during the operation of the cluster lifters. Whether it is the main cylinder of the hydraulic actuator 3 or the upper and lower anchor cylinder, they must coordinate their actions under the control of the computer during the lifting operation to create conditions for synchronous lifting. By adjusting the frequency converter to control the running speed of the lifter, the synchronous running of each point of the lifted component is maintained to keep its aerial attitude and complete the synchronous lifting. The operator can observe the hydraulic lifting process and relevant data and (or) issue control instructions through the man-machine interface of the hydraulic synchronous computer control system in the central control room.

[0102] Ground assembly of the roof grid

[0103] Ground assembly process of the roof grid

[0104] Step 1: Measure and set out the lines directly below the projection of the installation position. Step 2: Erect the falsework to install the lower chord balls, and adjust the elevation of the lower chord balls through the columns. Step 3: Install the lower chord bars and weld them to the joint balls. The lower chord bars at the positions of the steel columns are not installed temporarily, and the overall installation accuracy is rechecked. Step 4: Erect the supports to install the upper chord balls and adjust the elevation of the upper chord balls. Step 5: Install the diagonal web members and weld them to the joint balls. Step 6: Install the upper chord bars and weld them into a whole with the joint balls. Step 7: Install the purlins and intersperse the construction of paint and fireproof coatings. Step 8: The ground assembly of the grid is completed. Step 9: After the partial lifting of the grid, install the catwalk and the remaining peripheral supplementary members. Step 10: Lift the grid as a whole.

[0105] Ground assembly method of the grid

[0106] Grid assembly steps

[0107] (1) Assembly positioning of the grid center positioning reference

[0108] First, the Z coordinate and height difference of each lower chord ball are calculated according to the positioning size of the ball node and the arch value of the grid frame in the drawing. Then, the steel pipe column is placed on the ground according to the size of the grid frame ball in the central area. The elevation of each steel pipe head is verified with a tower ruler. The center cross line of the lower part of the steel pipe column is measured to determine the position of the ball node, and the internode rods are connected and assembled to form a lower chord quadrilateral unit grid. The upper chord center ball is then positioned with a vertical pole so that the center of the upper chord ball coincides with the center of the ground projection. Other web rods are connected and assembled to form a small unit as a reference control unit.

[0109] (2) Method and sequence of club positioning in the center area

[0110] 1. Assemble and lay out the grid; 2. Place a Φ194×6mm steel pipe head on a 2m×4m steel plate (20mm thick) to position and support the lower chord ball; 3. Assemble the lower chord ball, which rests on the upper part of the Φ194×6mm steel pipe head; 4. Assemble the lower chord rod; 5. Assemble the belly rod.

[0111] (3) Extended splicing method

[0112] After the center area is assembled, the assembly is gradually expanded outward by utilizing the mutual positioning between the balls and the rods.

[0113] 4. Hoisting method for ground assembly

[0114] The maximum rod specification of this project is Φ402×28mm, the cutting length is 3.67m, and the maximum weight of a single rod is 948kg. The largest single ball of this project is WSR9545, with a single weight of 1087kg. Considering the most unfavorable situation, the two largest rods and the largest single ball are welded and hoisted as a whole, with a total weight of: 2*948+1087=2983kg=2.983t.

[0115] The steel grid is assembled on the ground with a 25-ton truck crane. Hoisting conditions: the maximum hoisting weight is 2.983t; the weight of the sling and the hoisting equipment is 1t, and the total hoisting load is 4t; a 25-ton truck crane with a boom length of 17.3 meters is used for hoisting; the working radius is 4.5 meters to 10 meters. The hoisting is carried out by welding the ball to set the lifting lug and wire rope hoisting method.

[0116] 5. Tire frame setting and installation

[0117] Tire frame setting

[0118] For this project, the steel grid assembly jig uses Φ194×6mm steel pipes to support the lower chord balls of the grid. The bottom is welded to a 500×500×12mm steel plate. Horizontally, Φ127×4mm steel pipes are used, and the diagonal rods use L50×5mm angle steels to connect the jig into a whole to ensure the stability of the jig. The length of the Φ194×6mm steel pipe vertical poles is 0.5m to 1.7m, which are used to position and support the lower chord balls, corresponding one by one to the lower chord balls of the entire assembled grid. The jig material uses Q235B.

[0119] Jig foundation

[0120] The steel grid jig foundation is divided into three parts. The ground at the center of the circle is the already poured reinforced concrete ground. For this part, 2m*4m*20mm steel plates are laid, and jig columns are set on the steel plates; on the north side is the fire pool, and the roof of the fire pool has been poured. After calculation and communication with the design unit, the lower part of the top surface of the whole fire pool is strengthened with Ø48.3*3.2 steel pipe scaffolds. The vertical pole spacing in the transverse and longitudinal directions is 600mm, and the horizontal bar step distance is 1200mm. 2m*4m*20mm steel plates are laid on the fire pool, and jig columns are set on the steel plates; under the south stand, the stand has not been constructed yet, and the ground is backfilled soil ground. The backfill soil is tamped and rolled in layers. 2m*4m*20mm steel plates are laid on the ground, and jig columns are set on the steel plates.

[0121] 6. Ground assembly measurement and positioning

[0122] 1. Grid ground assembly measurement

[0123] (1) Assembly measurement preparation

[0124] The assembly measurement of the grid is monitored and positioned throughout the process by a total station.

[0125] The installation and positioning of the spherical grid nodes are achieved by measuring whether the three-dimensional coordinates of the node ball center are consistent with the designed coordinates. However, the node ball center cannot be directly observed, and only by measuring a certain surface above the ball center can the three-dimensional coordinates of this point be determined. This requires that this point passes vertically through the node center and the distance to the node is greater than the radius of the ball. Only when the vertical line passes through the point on the highest node spherical surface of the reticulated shell can the above conditions be maximally satisfied. For this reason, a special steel tray is made, on which a prism support is placed. After the bubble is leveled, all the above requirements can be met.

[0126] On-site, a steel tray with a diameter of 200mm and a wall thickness of 5mm is to be made, and its design depth is calculated as follows (the tray depth depends on the ball diameter size)

[0127] Determination of the tray depth:

[0128] According to the Pythagorean theorem of the right triangle in the cross-section:

[0129] The diameter (s) of the steel support to be manufactured on site is 200mm, and the wall thickness (d) is 5mm. Figure 3 As shown, the functional relationship between the depth of the outer wall of the tray and the ball diameter is: .

[0130] (2) Grid assembly measurement and construction

[0131] 1) Assembly detail control

[0132] During the assembly of the ball grid, the ball node positioning welding usually adopts the following steps:

[0133] Initial positioning

[0134] According to the calculated coordinates of the ball node installation position, the "ground sample method" is used to carry out the preliminary plane position layout of the ball node installation on the grid installation site (after compaction), set the marking line, and record the elevation of each point position.

[0135] For grid blocks installed using different construction methods, the assembly measurement control is as follows:

[0136] Table 1 Assembly measurement control

[0137] Serial number Assembly measurement control 1 For the grid units hoisted in sections, the coordinate lofting of each spherical node can be carried out on the assembly site according to the relative positions; 2 For the grid units assembled in-situ, it is necessary to calculate the three-dimensional coordinate positions of each spherical node in the entire grid structure according to the overall measurement coordinate system of the project for lofting and positioning;

[0138] After the preliminary marking of the axis is completed, set up the ball node installation jig at each ball node position, adjust the jig to the ball node positioning height to prepare for the initial placement of the ball;

[0139] Installation process control

[0140] In order to better control the assembly accuracy of the grid, the order of positioning is formulated as follows: first position the lower chord ball to be assembled → then position the lower chord member → determine the vertical web member and upper chord ball → then determine the upper chord member and diagonal web member.

[0141] The ball is hoisted to the in-place tire frame, and the matching prism for measurement is placed on the top of the ball through a self-made steel support. During the construction measurement process, a level ruler is used to adjust the position of the tray to make sure that the geometric center of the plane on it passes through the center of the ball in the vertical direction. The data obtained in this way can better control the ball node in the plane position according to the design accuracy. The elevation control should pay attention to removing the measured elevation from the radius of the sphere and the thickness of the tray wall.

[0142] Measurement Review

[0143] After the ball is accurately positioned, it needs to be temporarily fixed and then installed in the corresponding order. After the ball node is welded, the coordinates need to be checked again. If a small error is found, make up the difference at the next node to prevent continuous accumulation of errors.

[0144] 2) Assembly macro control

[0145] During the assembly process, each ball node must be strictly controlled in terms of plane position and elevation to ensure the overall accuracy of the small grid unit. If the grid area is large, it should be divided into measurement areas and the assembly accuracy should be controlled piece by piece to prevent the accumulation of errors caused by large-scale assembly and welding.

[0146] Most of the grids are assembled on the ground and lifted up in blocks. It is difficult to control the accuracy of such a large-scale grid during the construction and assembly process. The errors mainly come from the installation errors of each ball node and the accumulation of welding (shrinkage) errors.

[0147] In view of the measurement and control problems existing in the above-mentioned grid assembly process, the grid blocks to be hoisted in blocks are divided into blocks for measurement and control, and the average side length of the blocks is controlled to be around 30 meters after division. Each block is measured and controlled according to the principle of block-by-block control.

[0148] 3) Key point accuracy control

[0149] During the process of block assembly and block lifting, the grid frame will inevitably involve high-altitude docking. The accuracy of the ball node at the docking point directly affects the appearance of the blocks (whether the transition is smooth) and the force system of the components. Therefore, the assembly control key point (the node for docking with other blocks) is set at the ball node on the outermost side of the assembly unit. Its assembly accuracy is the key point of assembly control and needs to be repeatedly reviewed.

[0150] (3) Standards for control of grid assembly accuracy

[0151] The grid installation accuracy is controlled by using a total station to check each point, and the installation error is strictly controlled in accordance with the relevant regulations of the "Code for Acceptance of Steel Structure Construction Quality":

[0152] Table 2 Warning values ​​for steel grid structure installation (mm)

[0153]

[0154] 2. Positioning of the upper string ball

[0155] After the lower chord ball is hoisted onto the steel pipe column of the tire frame, first install the four lower chord balls at the center of the circle, remeasure the position and elevation of the axis of the lower chord ball, adjust it through the fall chain, and fix it on the tire frame column after it meets the requirements. Install the lower chord rod to form a lower chord quadrilateral unit grid. After the vertical pole and the upper chord ball are assembled on the ground, they are hoisted to the lower chord ball and spot welded to fix it. Use the vertical pole to fix the position and elevation of the upper chord ball so that the center of the upper chord ball coincides with the center of the ground projection. Connect and assemble other web rods to form a small unit as a reference control unit.

[0156] The maximum thickness of the grid structure is 5.5 meters. When assembling the upper chord members, a movable scaffold is used for assembly. The columns, cross braces, and diagonal braces of the self-made movable scaffold are erected using 40*40*3 square tubes.

[0157] The movable scaffold is convenient to assemble and disassemble, flexible to move, and convenient for personnel to go up and down. The members and balls are hoisted by a crane, and the personnel operate standing on the scaffold. A 1.2-meter railing is set on the upper part of the scaffold for hanging safety belts.

[0158] 7 Hoisting of Steel Grid Structure

[0159] 7.1 Analysis of Hoisting Conditions

[0160] The installation height of the steel structure is high. If the conventional piecemeal high-altitude bulk assembly method is used, not only is the high-altitude assembly and welding workload huge, but also there are relatively large quality and safety risks, and the construction difficulty is relatively high. Based on the successful experience of similar projects in the past, using the "hydraulic synchronous lifting technology for super-large components" to lift and install the steel structure can greatly reduce the installation construction difficulty and effectively ensure the quality, safety, and progress of the project.

[0161] 7.2 Description of Hydraulic Lifting

[0162] The grid structure is disconnected at the position outside the supports at the top of the structural columns. The grid structure is assembled at its projected floor (ground) surface and then directly lifted from the ground as a whole to the designed position (the concrete structural members that interfere with the assembly position are constructed after the grid structure is lifted). This forms the "overall hoisting plan for the grid structure". That is, the main structure is disconnected at the column supports, the entire grid structure is assembled on the falsework at a certain elevation below the lifting elevation, a temporary lifting support 2 is set at the top of the concrete column as the upper lifting point, a hydraulic jack 3 is arranged above the lifting support 2, and it is connected to the lower lifting point 1 of the grid structure assembled on the ground through special steel strands. Through the extension and retraction of the hydraulic jack 3, the grid structure is gradually lifted to the designed elevation position, the lifting device is locked, the lifted grid structure is connected to the pre-installed section, and then staged unloading is carried out. After confirming that the entire structural weight has been transferred to the supports, the temporary measures and lifting equipment are removed, and the roof lifting work is completed.

[0163] 7.3 Specific Steps for Hoisting the Steel Grid Structure

[0164] Steps for lifting the steel structure:

[0165] Step 1: Assemble the part of the grid structure to be lifted at the projected position of the grid structure on the ground. At the same time, install the lifting support 2 at the top of the concrete column, and then hoist and install the lifting equipment above the lifting support 2. As Figure 4 shown.

[0166] Step 2: Install the lifting lower hanging point 1, connect the upper and lower hanging points 1 with steel strands; connect the hydraulic oil pipe between the hydraulic pump and the lifter, lay out the communication line between the computer and the lifter and other hydraulic lifting equipment and facilities, and debug them. After the debugging is completed, tension and pre-tighten the steel strands. Figure 5 shown.

[0167] Step 3: After the overall debugging of the hydraulic device 3, hydraulic pump source, and synchronous control system is completed, the hydraulic pump pressure is gradually loaded in sequence of 20%, 40%, 60%, 80%, and 100% until the structure is about 20cm off the ground, and it stays for more than 12 hours for observation; after all aspects are confirmed to be normal, the lifting operation is officially carried out. Figure 6 shown.

[0168] Step 4: Ensure the smooth flow of the lifting channel during the lifting process. After lifting to a certain height (satisfactory installation of the lower hanging transfer beam and the horseway), install the lower hanging structure. After the installation is completed, continue the formal lifting. Measure each lifting point once every 5m (the interval can be changed appropriately according to the data situation), and make "single point" fine-tuning according to the measurement results to ensure the synchronization of lifting. Figure 7 shown.

[0169] Step 5: Lift the structure to 1m away from the designed position, make fine adjustments to each lifting point, lift the structure as a whole to the original designed position, lock the lifting device, and re-measure whether the lifting height of each lifting point is consistent with the designed state. Figure 8 shown.

[0170] Step 6: Connect the lifted structure to the support ball part and conduct relevant inspections on the main welds. After confirmation, unload and transfer the load to the formal support. Then remove the temporary structure and equipment to complete the entire lifting process. Figure 9 shown.

[0171] 7.4 Hydraulic synchronous lifting technology

[0172] 7.4.1 Basic Principles of Hydraulic Synchronous Lifting Technology

[0173] The "hydraulic synchronous lifting technology" uses hydraulic press 3 as lifting equipment and flexible steel strand as load-bearing rigging. The hydraulic press 3 is a through-core structure and uses steel strand as lifting rigging. It has a series of unique advantages such as safety, reliability, light weight of the load-bearing parts themselves, easy transportation and installation, and no need for splicing in the middle.

[0174] The wedge-shaped anchors at both ends of the hydraulic unit 3 have a one-way self-locking function. When the anchors are working (tight), they will automatically lock the steel strands; when the anchors are not working (loose), the steel strands are released and can move up and down.

[0175] The hydraulic lifting process is shown in the following block diagram. One cycle of the hydraulic actuator 3 is one stroke, and the stroke is 250 mm. When the hydraulic actuator 3 repeats its action periodically, the heavy object to be lifted moves forward step by step.

[0176] Computer synchronous control technology

[0177] The hydraulic synchronous lifting construction technology adopts stroke and anchor sensor monitoring and computer control. Through data feedback and control instruction transmission, it can fully automatically realize various functions such as certain synchronous actions, load balancing, attitude correction, stress control, operation locking, process display, and fault alarm. Operators can observe the hydraulic lifting process and relevant data and (or) issue control instructions through the human-machine interface of the hydraulic synchronous computer control system in the central control room.

[0178] The lifting force of the hydraulic actuator is dynamically adjusted by the following method: Install pressure sensors on each hydraulic actuator to monitor the lifting force of the hydraulic actuator in real time; transmit the data of the pressure sensors to the synchronous control system, and the synchronous control system dynamically adjusts the output pressure of the hydraulic pump according to the difference in the lifting force of each hydraulic actuator; if the lifting force of a certain hydraulic actuator exceeds the preset threshold, the synchronous control system automatically reduces the lifting force of this hydraulic actuator and increases the lifting force of other hydraulic actuators. The synchronous control system is also communicatively connected to the protection controller.

[0179] 7.5 Lifting point setting and layout

[0180] In this case, a total of 20 lifting points are set according to the structural characteristics. The layout of the lifting points is shown in the figure:

[0181] 7.5.1 Setting of the upper lifting point

[0182] Combined with the characteristics of the structural stress system of this project and the layout of the structural lifting points, it is planned to set the lifting bracket 2 at the top of the concrete column as the upper lifting point. The lifting bracket is connected to the concrete column through embedded parts (MJ1, MJ2). The material of the lifting bracket 2 is Q355B. The cross-section of the cross beam is box-shaped B400×400×16×16, the vertical beam is made of H300×300×10×15, and the diagonal brace is P194×20

[0183] 7.5.2 Setting of the lower lifting point 1

[0184] The lower lifting point 1 is connected to the structure to be lifted, and then connected to the hydraulic actuator 3 of the upper lifting point through the special lifting ground anchor and steel wire rope. The structure is lifted through the repeated operation of the lifter. This form of lifting point is conducive to the installation and removal work at the construction site, and does not affect the butt joint installation of the original structural members, and the amount of temporary measures used is less.

[0185] The temporary short pipe for the lower sling is made of steel plate, with the short pipe being P194×20, and the material of both being Q355b. The lower sling is connected to the structure to be lifted through temporary rods. The cross-section of the temporary rods is P159x8 and P194x6, and the material is Q355b. It should be noted that the temporary rods may interfere with the structural rods. Therefore, the welding position at the end can be adjusted during the installation of the temporary rods to leave a position for welding the supplementary rods after lifting in place.

[0186] 7.5.3 Setting of Reinforcement Rods at Lifting Points and Treatment of Fracture Ends

[0187] In order to prevent the lifted part of the rods from colliding with the ring beam during the lifting process and to minimize the cantilever beam length of the lifting bracket 2 as much as possible, temporary lifting points need to be set outside the last circle of the original lower chord for use as lifting hanging points.

[0188] The lower end of the temporary lifting rod is set at the position shown in the following figure and as close to the ring beam as possible. As shown in the following figure, the lifting point can be 500 mm away from the outer skin of the ring beam.

[0189] 7.6 Configuration of Hydraulic Lifting System

[0190] The hydraulic lifting system mainly consists of hydraulic cylinders 3, pump source system, steel strands, sensing detection and computer synchronous control system.

[0191] 1. Configuration of Hydraulic Cylinders 3

[0192] Table 3 Configuration of Hydraulic Cylinders 3 at Lifting Points

[0193]

[0194] According to the provisions of the "Technical Specification for Integral Lifting of Heavy Structures and Equipment" GB51162 - 2016, the overall lifting capacity (total rated load of all hydraulic lifting cylinders) should not be less than 1.25 times the corresponding load standard value. In summary, the minimum safety factor for a single lifting point is 1.42, and the overall lifting safety factor is 1.86. The configuration of the hydraulic cylinders 3 in this case can ensure safety.

[0195] 2. Configuration of Hydraulic Pump Source

[0196] The number of hydraulic pump source systems is selected according to the number of lifters and referring to the reaction force values at each lifting point. When lifting the structure, a total of 3 sets of TJV - 60 hydraulic pump source systems are configured, and each pump source can control up to 6 - 7 hydraulic cylinders 3 at most.

[0197] In this scheme, according to the lifters and pump source systems, a set of YT - 6 type computer synchronous control and sensing detection system is configured for the steel structure.

[0198] 3. Configuration of Load - bearing Steel Strands

[0199] As a flexible load-bearing sling, high-strength low-relaxation prestressed steel strands are used. According to the weight of the steel structure, the configuration of the hydraulic jack 3 and the reaction force values of each lifting point, steel strands with a diameter of 15.20 mm are selected for the hydraulic jack 3.

[0200] According to the "Technical Specification for the Overall Lifting of Heavy Structures and Equipment", the configuration principle of the load-bearing steel strands shall not have loose strands or broken wires, and a safety factor of the steel strands not less than 2.0 can ensure safety.

[0201] The minimum safety factor of the steel strands in a single hydraulic jack 3 is 3.01, which meets the specification requirements and can ensure the safety of this lifting.

[0202] 4. Configuration of the Synchronous Control System

[0203] In this scheme, based on the lifter and the pump source system, a set of YT-6 type computer synchronous control and sensing detection system is configured for the steel-connected structure.

[0204] 7.7 Installation of Hydraulic Lifting Equipment

[0205] 7.7.1 Hydraulic Jack 3

[0206] 1) Align the opening center of each lifter with the lifting crossbeam; adjust the position according to the orientation of the hydraulic lock; fix the bottom of each lifter with a pressing plate.

[0207] 7.7.2 Lifting Anchor

[0208] 1) Align the steel strand holes in each lifting anchor with the steel strand holes of the anchor sling; fix the bottom of each lifting anchor with a pressing plate; leave a certain gap between the lifting anchor and the lower sling when fixing the lifting anchor to enable the anchor to rotate freely along the circumferential direction.

[0209] 7.7.3 Load-bearing Steel Strands

[0210] The installation of the steel strands selects different methods according to the actual situation. The steel strands under the lifter are inserted into the corresponding lifting anchor directly below the lifter and locked (try to make the bottom of the protruding steel strands level). The remaining steel strands at the top of each lifter should be led out along the guide frame.

[0211] The installation operation process of the steel strands is as follows:

[0212] Cut the steel strand into the specified length with a grinding wheel cutting machine or gas cutting, and use a grinding machine or gas cutting to repair the two ends of the steel strand to be flat, smooth, and without loose strands; install the guiding plate directly below the lifter, adjust the position of the holes on the guiding plate so that they are aligned with the anchor holes of the lifter (pay attention to the triangular structure), and temporarily fix it; use a conduit to check the sky anchor, upper anchor, middle partition, lower anchor, safety anchor, and the holes of the guiding plate of the lifter from top to bottom to ensure that all 7 holes correspond; make marks on the guiding plate. Usually, the inner ring hole pointing outward along the layout direction of the lifter is the No. 1 hole; each steel strand of the lifter must be inserted alternately in left-handed and right-handed directions; start from the No. 1 hole above the sky anchor with the conduit, pass through 6 layers from top to bottom, and ensure the correct position; then insert the guiding pin into the conduit, screw the "bullet head" onto the thread of the guiding pin below the guiding plate, and insert the steel strand to be inserted into the "bullet head"; using the steel strand as the main driving force, pass through each layer in turn, and lock the remaining part of the steel strand at the top of the lifter to the sky anchor with a temporary anchor plate; after every 2 steel strands are inserted, clamp the steel strands in pairs with a clamp to prevent the steel strands from slipping from the air; generally, first insert a small part of the outer ring, then insert all of the inner ring, and then insert the remaining outer ring (insert alternately in left-handed and right-handed directions); after all the steel strands are inserted, lock the steel strands with the upper and lower anchor hydraulic cylinders and lock the sky anchor; lower the guiding plate to above the lower suspension point 1 with a soft rope, adjust the orientation of the guiding plate, and pay attention to the direction of the No. 1 marked hole; if the bottom ends of the steel strands are uneven after being inserted, draw a horizontal line on all the steel strands at an appropriate position, cut off the steel strands below the line, and repair the ends of the steel strands to be smooth; adjust the position of the ground anchor hole so that it is aligned with the hole of the guiding plate, insert the steel strands into the ground anchor in sequence and straighten them, and lock the steel strands.

[0213] 7.7.4 Connection of Hydraulic Pipelines

[0214] When connecting the oil pipes, the combined washers inside the oil pipe joints should be removed, and there should be O-rings on the corresponding pipe joints or butt joints; the oil pipes at the lower positions should be connected first to prevent the oil in the oil pipes from flowing back. The oil pipes between the pump station and the lifter should correspond one by one and be connected one by one; connect the oil pipes in the parallel or series manner specified in the plan to ensure correctness, and conduct a comprehensive review after connection.

[0215] 7.7.5 Connection of Control Lines and Power Lines

[0216] Connection of various sensors; connection of the control signal lines between the hydraulic pump station and the lifter; connection between the hydraulic pump station and the computer synchronous control system; connection of the power lines between the hydraulic pump station and the distribution box within 5 m around (using a 25-square 5-core copper cable).

[0217] 7.7.6 Connection of Hydraulic Pump Source System

[0218] The pump source layout is based on the principle of being close to the lifter to make the hydraulic oil pipes between the lifter and the pump source as short as possible. The specific layout will be determined according to the on-site situation.

[0219] 7.7.7 Arrangement of Computer Synchronous Control System

[0220] One set of YT-6 computer synchronous control system is configured for this project. This system is small in size and light in weight (the same volume as a computer). To enhance the simplicity of control operation and construction work, the synchronous control system can be arranged close to the hoist, pump source system, etc., facilitating connection with the hoist and pump source system. Rain protection should be well done around it to ensure a quiet environment.

[0221] 7.8 Quality Control of Grid Frame Hoisting

[0222] 7.8.1 Hoisting Synchronous Control Strategy

[0223] To ensure the safety of the structure during hoisting, according to the arrangement of hoisting suspension points, a synchronous hoisting and unloading in-place control strategy of "equalizing oil pressure at suspension points, adjusting structural attitude, controlling displacement synchronization, and unloading in stages" is proposed. The control system realizes the control of the hoisting attitude and load of the steel according to the above control strategy and specific algorithms. During the hoisting process, from the perspective of ensuring the safety of structural hoisting, the following requirements should be met: ensure that the loads on each suspension point of the same motor in the pump station are evenly distributed; ensure the stability of the hoisted structure in the air, that is, require each suspension point to maintain a certain synchronization during hoisting.

[0224] 7.8.2 Trial Hoisting

[0225] Based on the theoretical load of the main structure, the hoisting equipment at each hoisting suspension point is loaded in stages, which are 20%, 40%, 60%, and 80% in sequence. When it is confirmed that there is no abnormality in each part, it can be continuously loaded to 90% and 100% until the steel is completely lifted off the ground. After each stage of loading, the structural state of the relevant stress points should be checked, and the elevation difference and deflection of the steel should be monitored by a total station for leveling after lifting off the ground. All monitoring data during the loading process should be completely recorded. When the steel is about to leave the assembly jig (or the ground) during the staged loading, it may be that each point does not leave the ground simultaneously. At this time, the hoisting speed should be reduced, and the ground leaving situation of each point should be closely observed. If necessary, "single-point movement" hoisting should be carried out. Ensure that the structure leaves the ground smoothly and each point is synchronous. After the staged loading is completed, the structure is hoisted about 50 mm away from the assembly jig and then paused for 12 hours for a comprehensive inspection. During the pause period, professional personnel are organized to conduct special inspections on the hoisting supports 2, steel, hoisting slings, connecting components, and each hoisting equipment. After the pause period, each professional group summarizes the inspection results. After the lifting command headquarters reviews and confirms that there are no hidden dangers and problems, the general commander issues an official lifting order.

[0226] 7.8.1 Formal Hoisting

[0227] When the above situation is normal, the formal lifting begins. During the entire synchronous lifting process, the following should be checked at any time: the even loading of each hoisting point lifter; the overall stability of the upper hoisting point platform; the overall stability during the steel lifting process; the synchronism of each hoisting point controlled by the computer.

[0228] 7.8.2 Lifting and positioning

[0229] After the steel is synchronously lifted to near the design position, it pauses. Each hoisting point is finely adjusted to accurately lift the structure to the design position. The lifting equipment pauses and locks to keep the aerial attitude of the structure stable. Finally, the post-installed members are concentrated for butt welding. They are the sky anchor, upper anchor, and lower anchor respectively. During the process of the component staying in the air, each anchor changes from the hydraulic locking state to the mechanical self-locking state. For this project, since the connection belongs to the beam structure with a large projected area, the wind load (above level six) has a certain impact on the lifting and hoisting process. Temporary component balls 5 are set on the roof grid. These temporary component balls 5 are wrapped outside the temporary joint ball or on the upper chord rod and are set at the connection of the components of the roof grid. These temporary component balls 5 will be removed after installation. Among them, horizontally telescopic support members are provided inside the temporary component balls 5 near the concrete columns. A wind speed sensor is installed on the concrete column. The wind speed sensor and the support members are both communicatively connected to a protection controller. The wind speed sensor can detect the current wind speed in real time and transmit the wind speed data to the protection controller. After receiving the current wind speed data, the protection controller compares it with a preset wind speed threshold. If the current wind speed data exceeds the preset wind speed threshold (such as level six wind force), the protection controller will control the support members to telescopically extend or retract horizontally until the distance between it and the concrete column does not exceed 1 centimeter (such as 2 mm). At the same time, a displacement sensor is provided at the free end of the support member. The displacement sensor is used to detect the distance between the free end of the support member and the concrete column and feedback the detection data to the protection controller. The protection controller precisely controls the telescopic extension of the support members according to the data feedback by the displacement sensor to ensure that the distance between it and the concrete column meets the requirements. Through this protection measure, the stability of the roof grid can be effectively enhanced in windy weather, the impact caused by strong wind on the roof grid can be reduced, and the safety and smooth progress of the construction process can be guaranteed.

[0230] Adjustment allowable range when the steel grid is in place

[0231] During the hydraulic lifting process, it is necessary to ensure that the steel strand connecting the upper hoisting point (lifter) and the lower hoisting point 1 (ground anchor) is always vertical, that is, it is required that the upper hoisting point of the lifting bracket 2 and the lower hoisting point 1 of the beam rod are accurate during the initial positioning. According to the clamping method of the inner anchor cylinder of the lifter and the steel strand and the test data, generally, the offset angle of the upper and lower hoisting points 1 is controlled within 1 degree.

[0232] 7.9 Reinforcement of concrete columns during the grid lifting process

[0233] The lifting points of the grid are set at the elevation of 25.55m. However, the concrete columns with downward chord force are provided with reverse force concrete cross beams starting from the elevation of 19.95m. Horizontal beams are set at the above elevations (with a height of 5.6m). To increase the bending moment of the concrete columns with downward chord force and prevent deformations such as cracks in the concrete columns, after being reviewed and approved by the design unit, reinforcement measures are set for the concrete columns with downward chord force of the grid.

[0234] Specific construction method of the reinforcement measures: At the elevation of 19.95m, embedded parts MJ3 are set on the concrete beam outside the concrete column with downward chord force of the grid; at the elevation of 24.01m, embedded parts MJ4 are set on the concrete column with downward chord force of the grid; they are connected by seamless steel pipes with Ø152*8 to form a reverse force constraint on the concrete column.

[0235] Hoisting and unloading of the steel grid

[0236] 8.1 Unloading process

[0237] After the grid installation is fully completed, in order to make the grid reach the best design state after unloading and enable more effective stress release and internal force redistribution when the grid contacts the supports, the meteorology of the day should be inquired in advance to ensure that the temperature, wind direction and wind speed are within the design values of the grid. At the same time, check the force conditions of the lifting points of each lifting frame, check the power supply, circuit and the integrity of the state of the terminal equipment of the lifting frame, and conduct a detailed technical disclosure and precautions to all relevant personnel participating in the grid unloading process. After doing a good job in the relevant disclosure work, the unloading work of the grid can be carried out. Unloading is carried out according to the analysis results of the mechanical model of the grid in the unloading state.

[0238] (1) Similar to the lifting condition, unloading is also carried out by zoning and point-by-point grading, successively 20%, 40%, 60%, 80%. When it is confirmed that there is no abnormality in each part, unloading can continue to 100%, that is, the steel strands of the lifters are no longer stressed, and the structural load is completely transferred to the foundation, and the structural force form is transformed into the design condition.

[0239] (2) During the unloading process, check the force changes of each lifting point at any time.

[0240] (3) When unloading, there may be asynchronous unloading at each point. At this time, the unloading speed should be reduced, and the unloading conditions of each point should be closely observed with a level to ensure smooth unloading of the grid and synchronization of each point.

[0241] (4) In this project, 20 groups of lifting frames are set for the grid lifting area, and the expected unloading duration is 3 hours.

[0242] 8.2 Grid placement and unloading method

[0243] The synchronous descent method is adopted for the grid frame to be in place and unloaded. According to the principle of "overall synchronous and proportional descent", that is, all hydraulic cylinders 3 descend synchronously. Observe whether there are any abnormal phenomena in the grid frame and the lifting equipment. If everything is normal, conduct the second descent until the lower chord balls of the grid frame are in full contact with the seismic hinge supports. After the grid frame nodes and supports are in place and connected, weld and fix the lower chord balls of the grid frame and the seismic hinge supports, and conduct inspection and acceptance.

[0244] 8.3 Control Measures for Lifting Stability and Synchronization

[0245] When the steel is hovering off the ground for the first time, measure the elevation of each lower hanging point 1, and ensure that the entire steel is in a horizontal state before lifting by fine-tuning the lifter; conduct a data measurement of lifting synchronization (measurement of the lifting height of each hanging point) every time the height is lifted by about 5 - 6m. If it is found that the lifting of each hanging point in the previous stage is not coordinated, adjust the structure horizontally through the action of single or multiple oil cylinders, and then conduct the next stage of lifting after re-measurement is qualified; the computer control personnel on the ground must keep in smooth communication with the pump station operators, measurement personnel and other personnel, timely understand the status of the oil cylinders / pump stations and the lifted steel, and then combine the relevant data on the calculator control interface and observations to issue control instructions for the lifting process, reasonably control the lifting speed and the actions of each oil cylinder, and ensure the smoothness and synchronization of the lifting.

[0246] 9 High-altitude Assembly of Grid Frame

[0247] After the grid frame is lifted in place, start assembling the in-place ring in the air. After the assembly of each point is completed, the grid frame is lowered onto the support. At this time, the temporary grid can be removed, and the temporary grid should be removed in a head-to-head order.

[0248] For the high-altitude assembly of the grid frame, the high-altitude loose assembly method is adopted. First, assemble the supports without lifting frames, and after measurement is correct, then assemble the supports with lifting frames. After re-measurement is correct, the entire grid frame is lowered onto the support.

[0249] The components for high-altitude loose assembly are hoisted and assembled at high altitude by crawler cranes.

[0250] For the circumferential outrigger and down-turned section, small-unit assembly is carried out on the ground and constructed by the high-altitude butt-joint method. After the roof grid frame is in place, the circumferential grid frame is prefabricated and hoisted on the ground. One hoisting unit is formed between every three welded balls, with a weight of 6.8 tons, and it is docked with the roof grid frame in the air using a crane and a mobile scaffold.

[0251] Installation of Transfer Layer and Gallery

[0252] Wait for the grid frame to be partially lifted and hover, and then install the transfer layer and the gallery. The loads of the transfer layer and the gallery are applied to the lifters.

[0253] 10.1 Installation Technology of Eccentric Gallery

[0254] According to the site conditions, and in principle of ensuring safety and minimizing high-altitude operations and high-altitude welding, the installation plan for the catwalk is determined as follows:

[0255] 1. On the ground, install the 2 joists (the lower joists of the outer sphere and the lower joists of the inner sphere) between the 4 suspension rods of each unit on the lower support plates of the suspension rods. After verifying that the dimensions meet the requirements, weld the joists to the support plates.

[0256] 2. Adjust the distance between the two joists according to the drawing dimensions. After meeting the requirements, install the pre-fabricated catwalk platform plates on the two joists. The two ends of the support beams on both sides of the bottom of the platform plate are respectively placed on the welded steel plates on the two joists. After precise adjustment and positioning, weld the two ends of the channel steel / rectangular tube of the support beams on both sides of the bottom of the platform plate to the steel plates. Then install the railings on both sides of the catwalk platform. In this way, the assembly of one catwalk installation unit block is completed and ready for hoisting. Assemble other unit blocks in the same way successively.

[0257] 3. Transport the assembled unit blocks to the ground near the installation location. The weight of each hoisting unit block is about 4000 kg. According to the site conditions, it is planned to use 2 10-ton electric chain hoists for vertical hoisting in the installation of the unit blocks of this project. Before hoisting, transport the unit block to be hoisted to the ground below the hoisting position. Hang the electric chain hoist on the component above the hoisting position through a sling. Conduct a trial hoist before lifting. After ensuring the balance of the hoisted component, carry out the hoisting. After lifting to the installation position, arrange one installer on each of the corresponding spherical joints at the installation position of the grid catwalk, and respectively weld and fix the upper ends of the 4 suspension rods of the unit block to the bolt sphere, then the hook can be released. The installation of one catwalk unit block is completed, and then install the next unit block successively.

[0258] 4. After the installation of the unit blocks between adjacent suspension rods is completed, supplement and install one span of the platform plates and railings between them, and weld them to the adjacent single pads of the joists. Install in this method and sequence until the overall installation of the eccentric catwalk is completed.

[0259] 5. When hoisting the unit blocks, it is planned to symmetrically bind two 4m-long slings at both ends of the platform plate of the hoisting block. After the trial hoist is balanced, it can be hoisted into place. Tie a guy rope on the hoisting block before hoisting to assist in positioning.

[0260] After the overall lifting of the roof grid and the catwalk to the designed height, the following steps are also included: Set up temporary support frames around the roof grid. The height of the temporary support frames is adjustable and is used to temporarily support the roof grid after the lifting is completed; By adjusting the height of the temporary support frames, align the connection points between the roof grid and the concrete columns; Fix the roof grid to the concrete columns to complete the installation.

[0261] The overall lifting construction method of the multi-layer grid structure of the present invention realizes efficient, safe and precise construction through in-situ overall assembly on the ground, hydraulic synchronous lifting and modular installation of eccentric catwalks, and is applicable to the grid structure of roofs with large spans and complex shapes, having broad application prospects.

[0262] Although the embodiments of the present invention have been disclosed as above, they are not limited to only the applications listed in the specification and embodiments. It can be fully applied to various fields suitable for the present invention. For those familiar with the field, additional modifications can be easily made. Therefore, without departing from the general concept defined by the claims and the equivalent scope, the present invention is not limited to specific details and the illustrated and described examples here.

Claims

1. A multi-layer grid overall lifting construction method, characterized in that: include: 1) Assemble the roof grid in situ on the ground; 2) Multiple concrete columns are arranged at intervals along the perimeter of the roof grid, and a lifting bracket is installed on the top of some of the concrete columns as a lifting hanging point, and a hydraulic device is installed on the lifting bracket; 3) Connecting each lower hanging point on the roof grid to each hydraulic press, and lifting the roof grid as a whole to a preset installation height; 4) Divide the bridleway into multiple bridleway installation unit blocks, transport the assembled bridleway installation unit blocks to the ground below the hoisting position, and perform vertical hoisting. After lifting to the installation position, connect the upper end of the bridleway installation unit block to the node ball at the corresponding ball node of the roof grid bridleway installation position until the overall installation of the bridleway is completed; 5) After the horseway is installed, the roof grid and the horseway are hoisted as a whole to the designed height; Wherein, a temporary component ball is arranged on the roof grid, and the temporary component ball is wrapped on the outside of the temporary node ball or on the upper chord, and the temporary component ball is arranged at the component connection of the roof grid, wherein a support rod that can be extended and retracted in the horizontal direction is arranged in the temporary component ball close to the concrete column, and a wind speed sensor is arranged on the concrete column, and the wind speed sensor and the support rod are both communicatively connected to a protection controller, and the wind speed sensor detects the current wind speed in real time and transmits the wind speed data to the protection controller, and the protection controller receives the current wind speed data and compares it with a preset wind speed threshold value, if the current wind speed data exceeds the preset wind speed threshold value, the protection controller controls the support rod to be extended and retracted in the horizontal direction to a distance from the concrete column of no more than 1 cm, and a displacement sensor is arranged at the free end of the support rod, and the displacement sensor is used to detect the distance between the free end of the support rod and the concrete column, and the displacement sensor is communicatively connected to the protection controller.

2. The multi-layer grid overall lifting construction method according to claim 1, characterized in that: The roof grid projection surface is circular, the upper chord surface is a spherical surface, the lower chord surface is a spherical surface with a horizontal center, the node connection form is a welded ball node, the structural form is a quadrangular pyramid grid, a plurality of bidirectional elastic ball hinge supports are arranged around the roof grid, the support form is a lower chord column point, and the lower structure is a concrete frame; The steps of assembling the roof grid in situ on the ground include: Tire frame erection and lower chord ball installation: Build the grid frame to assemble the tire frame. The tire frame uses steel pipes to support the lower chord ball of the grid frame, which is welded on the steel plate. Steel pipes are used in the horizontal direction, and the diagonal rods are connected into a whole with angle steels; Install the lower chord ball on the tire frame and weld it to the node ball; Install the upper chord ball, adjust the elevation of the upper chord ball, install the diagonal brace and weld it to the node ball, install the upper chord bar and weld it to the node ball to form a whole; Install the purlins to complete the overall assembly of the roof grid.

3. The multi-layer grid overall lifting construction method according to claim 1, characterized in that: The bridleway is an eccentric bridleway. During the lifting of the eccentric bridleway, the lifting force provided by each hydraulic unit is calculated by the following method: F1 = k×G×L2 / (L1 + L2) F2 = k×G×L1 / (L1 + L2) Among them, F1 is the lifting force of the hydraulic device on the side close to the center of gravity, F2 is the lifting force of the hydraulic device on the side far from the center of gravity, G is the total gravity of the eccentric bridleway, L1 is the horizontal distance from the center of gravity of the eccentric bridleway to the nearest support point, L2 is the horizontal distance from the center of gravity of the eccentric bridleway to the farthest support point, and k is the dynamic load coefficient during the lifting process; The method for determining the side close to the center of gravity and the side far from the center of gravity is as follows: a) During the ground pre-assembly stage, the geometric center of gravity of the eccentric bridleway is determined by weighing or three-dimensional modeling, and the center of gravity projection point is marked on the bridleway; b) Determine the structural eccentricity direction according to the design drawings of the eccentric bridleway; c) During hoisting, take the center of gravity projection point of the eccentric horseway as the reference, and measure the horizontal distance between the support point corresponding to each hydraulic device and the center of gravity projection point: if the horizontal distance from a certain support point to the center of gravity projection point is less than or equal to other support points, the hydraulic device corresponding to this support point is close to the center of gravity; if the horizontal distance from a certain support point to the center of gravity projection point is greater than other support points, the hydraulic device corresponding to this support point is far from the center of gravity; d) When there are multiple support points with equal distances, the eccentricity direction of the structure shall be used as the basis for judgment.

4. The multi-layer grid overall lifting construction method according to claim 1, characterized in that: In step 3), lifting the roof grid as a whole also includes: connecting the hydraulic device and the hydraulic pump source, and connecting both to the synchronous control system, connecting the lifting point of the roof grid to the hydraulic device through a steel strand, and gradually loading the hydraulic pump pressure to the roof grid structure at a certain distance from the ground in the order of 20%, 40%, 60%, 80%, and 100%, and then staying for a period of time, and then lifting; During the lifting process, each lifting point is measured every few meters, and single-point fine-tuning is performed based on the measurement results so that each lifting point is lifted synchronously. When it is lifted to 1m away from the designed position, each lifting point is fine-tuned and lifted as a whole to the designed position. A reflective sticker is attached to the bottom of the temporary construction ball and a "cross" is marked, and a total station is used for measurement.

5. The multi-layer grid overall lifting construction method according to claim 1, characterized in that: In step 4), the method for installing the horseway includes: dividing the horseway into a plurality of horseway installation unit blocks, installing two joists between four hangers arranged in the vertical direction of each unit block on the support plate at the lower end of the hangers on the ground, installing the horseway platform plate on the two joists, placing the two ends of the supporting beams on both sides of the bottom of the horseway platform plate on the welded steel plates on the two joists respectively, welding the two ends of the supporting beam channel steel or rectangular tube on both sides of the bottom of the horseway platform plate to the steel plates, and then installing the railings on both sides of the horseway platform above them, connecting the upper ends of the four hangers of the horseway installation unit block to the corresponding ball nodes of the roof grid horseway installation position, and after the horseway installation unit blocks between adjacent hangers are installed, a span platform plate and railings are additionally installed therebetween, and connected to the adjacent joists, and the installation is performed in this order until the overall installation of the horseway is completed.

6. The multi-layer grid overall lifting construction method according to claim 2, characterized in that: During the roof grid assembly process: the ground sample method is used to lay out the preliminary plane position of the ball node installation, and the positioning sequence is: first the lower chord ball, then the lower chord member, then the vertical web member and the upper chord ball, and finally the upper chord member and the diagonal web member; the ball node is temporarily fixed after positioning welding, and the coordinates are checked again after welding; the assembly area is divided, and the assembly accuracy is controlled piece by piece; the assembly control key points are set at the outermost ball nodes of the assembly unit.

7. The multi-layer grid overall lifting construction method according to claim 1, characterized in that: During the lifting process of the roof grid, a ruler is hung below the hanging point, and the center elevation of the ball node at each hanging point is marked on the side of the adjacent column. The height increase of each lifting point is intuitively reflected through the ruler, and compared with the lifting values ​​of each point on the lifting operation interface.

8. The multi-layer grid overall lifting construction method according to claim 1, characterized in that: In step 3), the lifting force of the hydraulic press is dynamically adjusted by: Install a pressure sensor on each hydraulic press to monitor the lifting force of the hydraulic press in real time; The data of the pressure sensor is transmitted to the synchronous control system, and the synchronous control system dynamically adjusts the output pressure of the hydraulic pump according to the difference in lifting force of each hydraulic unit; If the lifting force of a certain hydraulic unit exceeds a preset threshold, the synchronous control system automatically reduces the lifting force of the hydraulic unit and increases the lifting force of other hydraulic units.

9. The multi-layer grid integral lifting construction method according to claim 1, characterized in that: In step 5), after the roof grid and the horseway are hoisted to the design height as a whole, the following steps are also included: Temporary support frames are set around the roof grid frame, and the height of the temporary support frames is adjustable, which is used to temporarily support the roof grid frame after the lifting is completed; By adjusting the height of the temporary support frame, the connection points between the roof grid and the concrete columns are aligned; Fix the roof grid to the concrete columns to complete the installation.

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