WO2021120335A1

WO2021120335A1 - Cumulative lifting method for large-span unequal-height bidirectional curved surface grid

Info

Publication number: WO2021120335A1
Application number: PCT/CN2019/130695
Authority: WO
Inventors: 宋利鹏; 汪晓阳; 陈华周; 张步亭; 马新
Original assignee: 中建科工集团有限公司
Priority date: 2019-12-18
Filing date: 2019-12-31
Publication date: 2021-06-24
Also published as: CN111042542A

Abstract

A cumulative lifting method for a large-span unequal-height bidirectional curved surface grid, aiming at solving the problems in the prior art that construction methods commonly used for a large-span space bidirectional curved surface grid require many support measures, have a low construction efficiency and have a high construction cost; and the technical points of the cumulative lifting method lie in comprising the following steps: S1, performing calculation and analysis before construction; S2, performing calculation and control in construction; S3, installing a vertical supporting grid; S4, assembling a bidirectional curved surface grid; S5, providing lifting points; S6, performing cumulative lifting; and S7, installing fittings. The installation method of the present invention provides a compact structure, an industrialized assembly mode, a short installation period, and high operation flexibility.

Description

Cumulative lifting method for large-span unequal height bidirectional curved surface grid

Technical field

The invention relates to the technical field of grid construction, in particular to a cumulative lifting method for a large-span unequal height bidirectional curved surface grid.

Background technique

With the continuous emergence of large-span and large-area grid structures, the construction height and span of large-area grids continue to increase. Traditional construction methods not only increase the construction cost and lengthen the construction period, but also reduce the construction safety. Therefore, seeking a safe, fast, and low-cost construction method is one of the focuses of the current research on large-area and large-span grid construction.

The ultra-high arched grid structure is a grid structure with welded spherical nodes as the main form, which is suitable for columnar or arched structures with large span, light weight and reasonable stress. This type of structure is widely used in buildings such as airship depots, dry coal sheds, and building cement material reactors.

The structure of a domestic airship warehouse project is a curved grid with a span of 140 meters, a length of 266 meters, and an elevation of 116 meters at the highest point. The structure above the 64.237 meters elevation is an arched net shell, and the following is a flat net frame (the flat net frame is inclined 8°), all of which are in the form of a square quadrangular pyramid. The structure above the elevation of 24 meters is welded hollow sphere joints, and the following are intersecting joints. The overall structure is supported on the lower concrete independent foundation, and the supporting column feet are inserted.

At present, the commonly used methods of large-span and large-area grid structure construction are: (1) sliding frame method, (2) structure cumulative slip method, (3) folding and unfolding lifting method, (4) cantilevering method. Regarding the large-span and super-height grid structure with an arc-shaped reticulated shell on the roof and an inclined flat-plate grid on the facade, the above-mentioned construction schemes are lacking in terms of construction cost, construction quality, and construction safety. perfect.

At present, the design and construction of the ultra-high arched grid structure is still in the stage of exploration and research in my country and even in the world, and there are no cases of completion acceptance. Based on this situation, many research institutes, universities and construction units at home and abroad are actively conducting model test research and theoretical calculations.

Summary of the invention

Therefore, the technical problem to be solved by the present invention is to overcome the disadvantages of large-span space bidirectional curved surface grid construction methods in the prior art, such as large investment support measures, slow construction efficiency, and high construction costs, thereby providing a large-scale construction method. Cumulative lifting method for two-way curved surface grids with unequal spans.

The above-mentioned technical objectives of the present invention are achieved through the following technical solutions:

A method for accumulative lifting of large-span unequal-height two-way curved surface grids includes the following steps:

S1. Calculation and analysis before construction: use calculation software to calculate and analyze the whole construction process to ensure that the grid structure itself and the lifting system can meet the relevant mechanical and structural requirements during the construction process, and ensure that the construction process is safe and controllable;

S2. Computational control during construction: high requirements for synchronous control of hydraulic lifting construction, computer synchronous control system is used during construction, and detection during lifting is strengthened;

S3. Installation of the vertical support grid frame: adopt the measures of lattice type support frame and wind rope to temporarily fix the grid frame of the vertical support part;

S4. Assembling of two-way curved net frame: Assemble the two-way curved net frame with large span and unequal height on the assembled tire frame directly below the projection;

S5. Set up lifting points: install lifting brackets and hydraulic lifters on the vertical support grid structure, and reduce the number of lifting points under the premise of ensuring construction requirements;

S6. Cumulative lifting: Divide the two-way curved network frame in step S4 into several lifting zones, and install jacks at the bottom of the assembled tire frame that supports the grid structure on the facade, and lift each zone in turn from high to low. Subsequent partitions are gradually connected and gradually improved to form an overall shape and then lifted into place;

S7. Accessories installation: After the lifting is completed, add rods for assembly, and perform reinforcement treatment after the assembly is completed.

Optionally, in the step S2, a stress sensing sheet is set in the main stressed part to monitor the change of its internal stress, the stress ratio of the rod during the lifting process is controlled within 0.85, and the overall deformation of the structure is controlled at L/250, L is the distance between adjacent lifting points.

Optionally, the distance between the support frames is 20-45m, the wind rope is pulled at 2/3 of the height of the vertical support part, and the angle between the wind rope and the ground is 30-45°, The height of the façade supporting part is 50-75m.

Optionally, in the step S5, the lifting bracket is set on the ball node of the grid, and computer software is used to perform a simulation check. According to the check calculation result, the support area grid member is reinforced to make the height of the lifting bracket It is 0.5-1m higher than the height of the lifting point, and the model of the hydraulic lifter is determined according to the lifting reaction force of the lifting point, so as to set the steel strand, the safety factor of the steel strand is controlled in the range of 2-4 times Inside.

Optionally, in the step S5, before lifting, a steel cable is used to prestress the grid structure itself, the magnitude of the prestress is 500-1000 KN, which is used to resist the lifting reaction force.

Optionally, in the step S6, the configuration coefficients of the hydraulic lifts are the same, and the lifting is uniformly commanded by the control terminal, and the lift is controlled in sections with a 200mm stroke.

Optionally, in the step S6, make scale marks on the steel strand with an interval of 1 m, and record the distance from the clip on each jack to the nearest scale before lifting, as a reference for synchronization control; during the lifting process, Observe the steel bar scale of each lifting point, and control the asynchronous difference of each lifting point within the allowable range.

Optionally, in the step S6, the amount of retraction of the clamp varies from jack to jack. After lifting a certain number of cylinders, measure the distance from the clip to the scale, and analyze the synchronization of each lifting point based on the record before lifting. Individual adjustments are made to deviations in the lifting points.

The technical scheme of the present invention has the following advantages:

1. Low requirements for mechanical equipment. Due to the construction method of accumulative lifting and lifting in the patent of the invention, the mechanical equipment used in addition to the hydraulic lifter, hydraulic pump source system, synchronous control system, etc., only need to arrange a few small ground assembly machinery to hydraulically lift the curved net frame Part of the ground assembly can meet the construction requirements; compared with other construction schemes, it has the advantages of low construction machinery cost and abundant construction machinery equipment resources.

2. High construction efficiency. The two-way curved surface grid is first assembled into several small units on the ground, and then the assembled unit is hoisted to the assembled tire frame by hoisting machinery to assemble into an overall lifting unit. The installation of construction equipment and measures is simple, the construction process is convenient, and the construction efficiency high.

3. Low construction cost. The grid frame is assembled on the ground operation platform, and the amount of measures to set up the assembly platform is small. The machinery used is common small machinery and equipment, which is convenient and cheap to rent. Compared with the high-altitude bulk and block hoisting schemes, the construction cost is greatly reduced. .

4. High construction safety. Computer software is used for simulation and calculation, and the support area grid members are reinforced according to the results of the calculation, so that the height of the lifting bracket is 0.5m higher than the height of the lifting point, and the model of the hydraulic lifter is determined according to the lifting reaction force of the lifting point. With this setting of the steel strand, the safety factor of the steel strand is controlled within the range of 2-4 times, and by virtue of the stress sensing sheet, the stress ratio of the rod is controlled to be within 0.85 during the lifting process, and the deformation of the structure as a whole is controlled at L/ 250, L is the distance between adjacent lifting points.

5. The construction quality is easy to guarantee. The configuration coefficient of the hydraulic lifter is the same, and the lifting is uniformly commanded by the control terminal, and is controlled in sections with a 200mm stroke; mark the scale on the steel strand with a spacing of 1m, and record the clip on each jack to the nearest scale before lifting The distance is used as the benchmark for synchronous control; during the lifting process, observe the rebar scale of each lifting point, and control the asynchronous difference of each lifting point to be within the allowable range; the retraction amount of the fixture varies with the jack, and a certain number of cylinders are being lifted After that, measure the distance from the clip to the scale, analyze the synchronization of each lifting point based on the records before lifting, and make individual adjustments to the lifting points with deviations.

Detailed ways

In order to make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with embodiments. It should be understood that the specific embodiments described here are only used to explain the present invention, but not used to limit the present invention.

Example 1:

Specifically, a stress sensing sheet is attached to the main stressed part of the grid in advance to monitor its internal stress changes;

S3. Installation of the vertical support grid: the grid type support frame and the wind rope are adopted to temporarily fix the grid of the vertical support part. In this embodiment of the present invention, the wind rope is pulled on the vertical support part. At 2/3 of the height, the angle between the wind rope and the ground is 45°, the distance between the support frames is 20m, and the height of the vertical support part is 50m;

S4. Assembling of two-way curved net frame: Assemble the two-way curved net frame with large span and unequal height on the assembled tire frame directly below its projection, so that the two-way curved net frame is first assembled into several small units on the ground, and then Use hoisting machinery to hoist the assembled unit to the assembled tire frame to assemble into an integral lifting unit;

S5. Set up lifting points: install lifting brackets and hydraulic lifters on the vertical support grid structure, and reduce the number of lifting points under the premise of ensuring construction requirements, so as to control the rods during the lifting process by virtue of the stress sensing sheet The stress ratio is within 0.85, and the overall deformation of the structure is controlled at L/250, where L is the distance between adjacent lifting points;

Specifically, the lifting bracket is set on the ball node of the grid, and computer software is used for simulation and calculation. According to the verification results, the support area grid member is reinforced, so that the height of the lifting bracket is 0.5m higher than the height of the lifting point, and the hydraulic The type of the lifter is determined according to the lifting reaction force of the lifting point, and the steel strand is set accordingly, and the safety factor of the steel strand is controlled within the range of 2-4 times;

In addition, it is necessary to set temporary rods and temporary balls at the lifting position as the lower lifting point. Each lifting point is set with 3 temporary rods to limit the temporary rods from conflicting with the structural members. The lower lifting points are welded balls and welded. The diameter of the ball is controlled at 500-800mm, and a cross stiffening plate is added in the welding ball;

In this embodiment of the present invention, the grid structure is divided into four unit grids on the facade, and each unit grid is cumulatively lifted into place through multiple sets of lifting systems and the front unit grid, that is, the first unit grid is in place. The assembled tire frame is assembled into a whole, and multiple sets of lifting systems are set on both sides of the unit grid to raise the first unit grid to a certain height simultaneously, and then use a large crawler crane to hoist the block unit grid to complete the second unit grid Assemble. At this time, the assembled tire frames of the first and second unit grids are written in, and part of the grid is supported on the vertical surface. Then the lifting system of the first unit grid is removed and transferred to the second unit grid , Raise the first and second unit grids to a certain height simultaneously, and so on to complete the installation of the subsequent unit grids;

During the lifting process of the grid, in order to prevent the lifting reaction force from damaging the grid structure itself, steel cables are used to prestress the grid structure itself before lifting. The prestress is 500-1000KN to resist the lifting. Reaction force;

In the process of grading and accumulative lifting, the closing of different classes is the focus of accuracy and deformation control. Compared with the traditional overall lifting method, the difference is that when the grading and accumulative lifting are closed, different levels are in different stress states: in this case After the two-level lifting partitions are closed together, due to the different stress states, after forming an overall lifting, due to the release of stress, it will cause deformation of the grid. In order to solve this problem, the configuration coefficient of the hydraulic lifter is the same, and the lifting is uniformly commanded by the control terminal, and the 200mm stroke is controlled in sections; the scale marks are made on the steel strand with a distance of 1m, and the jacks are recorded before lifting. The distance from the clamp to the nearest scale is used as the benchmark for synchronization control; during the lifting process, observe the rebar scale of each lifting point to control the asynchronous difference of each lifting point within the allowable range; the retraction amount of the clamp varies with the jack. After lifting a certain number of cylinders, measure the distance from the clip to the scale, analyze the synchronization of each lifting point based on the records before lifting, and make individual adjustments to the lifting points with deviations;

Example 1:

S3. Installation of the vertical support grid: the grid type support frame and the wind rope are adopted to temporarily fix the grid of the vertical support part. In this embodiment of the present invention, the wind rope is pulled on the vertical support part. At 2/3 of the height, the angle between the wind rope and the ground is 30°, the distance between the support frames is 45m, and the height of the vertical support part is 75m;

Specifically, the lifting bracket is set on the ball node of the grid, and computer software is used for simulation and calculation. According to the results of the verification, the support area grid member is reinforced, so that the height of the lifting bracket is 1m higher than the height of the lifting point, and the hydraulic lifting The model of the device is determined according to the lifting reaction force of the lifting point, and the steel strand is set accordingly, and the safety factor of the steel strand is controlled within the range of 2-4 times;

In this embodiment of the present invention, the grid structure is divided into seven unit grids on the facade, and each unit grid is cumulatively lifted into position with the front unit grid through multiple sets of lifting systems, that is, the first unit grid is in place. The assembled tire frame is assembled into a whole, and multiple sets of lifting systems are set on both sides of the unit grid to raise the first unit grid to a certain height simultaneously, and then use a large crawler crane to hoist the block unit grid to complete the second unit grid Assemble. At this time, the assembled tire frames of the first and second unit grids are written in, and part of the grid is supported on the vertical surface. Then the lifting system of the first unit grid is removed and transferred to the second unit grid , Raise the first and second unit grids to a certain height simultaneously, and so on to complete the installation of the subsequent unit grids;

In the process of grading and accumulative lifting, the closing of different classes is the focus of accuracy and deformation control. Compared with the traditional overall lifting method, the difference is that when the grading and accumulative lifting are closed, different levels are in different stress states: in this case After the two-level lifting zones are closed together, due to the different stress states, after forming an overall lifting, due to the release of stress, it will have a deformation effect on the grid. In order to solve this problem, the configuration coefficient of the hydraulic lifter is the same, and the lifting is uniformly commanded by the control terminal, and the 200mm stroke is controlled in sections; the scale marks are made on the steel strand with a distance of 1m, and the jacks are recorded before lifting. The distance from the clamp to the nearest scale is used as the benchmark for synchronization control; during the lifting process, observe the rebar scale of each lifting point to control the asynchronous difference of each lifting point within the allowable range; the retraction amount of the clamp varies with the jack. After lifting a certain number of cylinders, measure the distance from the clip to the scale, analyze the synchronization of each lifting point based on the records before lifting, and make individual adjustments to the lifting points with deviations;

Obviously, the above-mentioned embodiments are merely examples for clear description, and are not intended to limit the implementation manners. For those of ordinary skill in the art, other changes or modifications in different forms can be made on the basis of the above description. It is unnecessary and impossible to list all the implementation methods here. The obvious changes or changes derived from this are still within the protection scope created by the present invention.

Claims

A cumulative lifting method for a large-span unequal-height two-way curved surface grid is characterized in that it comprises the following steps:

S1. Calculation and analysis before construction: use calculation software to calculate and analyze the whole construction process to ensure that the grid structure itself and the lifting system can meet the relevant mechanical and structural requirements during the construction process, and ensure that the construction process is safe and controllable;

S2. Computational control during construction: high requirements for synchronous control of hydraulic lifting construction, computer synchronous control system is used during construction, and detection during lifting is strengthened;

S3. Installation of the vertical support grid frame: adopt the measures of lattice type support frame and wind rope to temporarily fix the grid frame of the vertical support part;

S4. Assembling of two-way curved net frame: Assemble the two-way curved net frame with large span and unequal height on the assembled tire frame directly below the projection;

S5. Set up lifting points: install lifting brackets and hydraulic lifters on the vertical support grid structure, and reduce the number of lifting points under the premise of ensuring construction requirements;

S6. Cumulative lifting: Divide the two-way curved network frame in step S4 into several lifting zones, and install jacks at the bottom of the assembled tire frame that supports the grid structure on the facade, and lift each zone in turn from high to low. Subsequent partitions are gradually connected and gradually improved to form an overall shape and then lifted into place;

S7. Accessories installation: After the lifting is completed, add rods for assembly, and perform reinforcement treatment after the assembly is completed.
The method for accumulative lifting of a large-span unequal-height two-way curved surface grid according to claim 1, characterized in that, in the step S2, a stress sensing sheet is arranged in the main force-bearing part to monitor the change of the internal stress, During the lifting process, the stress ratio of the rods is controlled within 0.85, and the overall deformation of the structure is controlled at L/250, where L is the distance between adjacent lifting points.
The method for accumulative lifting of a large-span unequal-height two-way curved surface grid according to claim 1, wherein, in the step S3, the distance between the support frames is 20-45m, and the wind rope pulls Set at 2/3 of the height of the vertical support part, the angle between the wind rope and the ground is 30-45°, and the height of the vertical support part is 50-75m.
The method for accumulative lifting of a large-span unequal-height two-way curved surface grid according to claim 1, characterized in that, in the step S5, the lifting bracket is arranged on the ball node of the grid, and computer software is used to perform Simulation check calculation, according to the check calculation results to strengthen the support area grid member, so that the height of the lifting bracket is 0.5-1m higher than the height of the lifting point, and the model of the hydraulic lifter is determined according to the lifting reaction force of the lifting point, In this way, the steel strand is set, and the safety factor of the steel strand is controlled within the range of 2-4 times.
The method for accumulative lifting of a large-span unequal-height two-way curved surface grid according to claim 4, characterized in that, in the step S5, before lifting, the steel cable is used to prestress the grid structure itself, The size of the prestress is 500-1000KN, which is used to resist the lifting reaction force.
The cumulative lifting method of a large-span unequal-height two-way curved surface grid according to claim 4, characterized in that, in the step S6, the configuration coefficients of the hydraulic lifters are the same, and they are uniformly commanded through the control terminal. Lifting is controlled in sections with a 200mm stroke.
The method for accumulative lifting of a large-span unequal-height two-way curved surface grid according to claim 4, characterized in that, in the step S6, mark marks are made on the steel strands with an interval of 1m, and the lifting Record the distance from the clamp on each jack to the nearest scale as the benchmark for synchronization control; during the lifting process, observe the scale of the steel bar at each lifting point, and control the asynchronous difference of each lifting point within the allowable range.
The method for accumulative lifting of a large-span unequal-height two-way curved surface grid according to claim 7, characterized in that, in the step S6, the retraction amount of the clamp varies with the jack, and a certain number of cylinders are lifted. After that, measure the distance from the clip to the scale, analyze the synchronization of each lifting point based on the records before lifting, and make individual adjustments to the lifting points with deviations.