Construction method of floor net rack jacking using joist frame

Abstract

A floor net rack jacking construction method using a joist frame is characterized by comprising the following steps: a, software modeling, calculation and analysis, b, net rack floor assembly, c, setting a plurality of joist frames, d, setting back jacking steel pipes, e, synchronously jacking the net rack, f, completing the net rack installation by edge sealing and rod supplementing, and g, net rack installation finishing and unloading. The floor net rack jacking construction method using a joist frame has the advantages of simple materials, simple and highly applicable method, rapid construction, convenient installation, labor saving and time saving, safety and reliability, economic applicability, and less space occupation.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of steel structure net rack jacking construction, in particular to a floor net rack jacking construction method using a joist frame. BACKGROUND

[0002] With the development of the construction industry, in order to obtain a greater sense of space, more and more buildings choose steel structure, and more and more buildings choose net rack roof structure. The biggest feature of these buildings is large span, and there are generally few or no support systems in the middle, which can provide the most open space. In the future, according to the use requirements, the use unit can be divided at any time, and the use is flexible and the obstacles are few. Among them, the steel structure net rack has the advantages of high strength, light weight, good seismic performance, fast construction speed, and beautiful appearance.

[0003] In the steel structure net rack structure, there are many construction methods for steel structure net rack installation methods, such as high-altitude bulk loading method, integral lifting method, integral jacking method, and block installation method. Among them, the high-altitude bulk loading method and the block installation method need to set up a temporary operation platform, which is mostly full-frame scaffolding, which has high cost and slow work efficiency. The integral lifting method and the integral jacking method have requirements for the structure form of the building, the lifting method must have a support point for installing the lifting frame, and the integral jacking method must ensure the stability of the jacking point and the jacking plane, and the jacking process is not hindered by other interference structures.

[0004] In actual construction, such as patent CN111719705A, a kind of large-span net rack jacking construction process is provided, which provides a kind of net rack jacking support frame with high safety, and such as patent CN216552430U, a kind of adjustable net rack jacking support is provided, which is used to eliminate the angle restriction between the jacked net rack and the jacking structure, and reduce the risk of deformation of the net rack during jacking.

[0005] However, the above technical solutions have the following defects: for some steel net rack structures located inside the building, the installation of large hoisting equipment is limited by the narrow site and the original building structure, and it is difficult to approach and use, and the high-altitude in-situ assembly of the steel net rack is difficult and the assembly precision is difficult to guarantee, and the jacking of the building floor will affect the structure of the floor, and the full-frame scaffolding under the floor is difficult to set up for back jacking operation, which has high cost, long time, and conflicts with other professional construction of civil engineering.

[0006] Therefore, the known net rack jacking method has the above-mentioned inconveniences and problems.

[0007] The present application provides a floor net rack jacking construction method using a joist frame. SUMMARY

[0008] The purpose of the present application is to solve the problem that most of the net rack bolt ball jacking points are located on the floor surface, and the floor surface thickness is only 120mm, which cannot bear the vertical load transmitted by the net rack structure during jacking, and a safe and reliable floor net rack jacking construction method using a joist frame is proposed to solve the problem of vertical load transmission during net rack jacking, and the load is transmitted to the floor concrete beam through the joist frame, and the vertical load is transmitted to the bottom plate foundation beam through the reverse jacking support under the beam.

[0009] To achieve the above object, the technical solution of the present application is:

[0010] A floor net rack jacking construction method using a joist frame, characterized in that it comprises the following steps:

[0011] a. Software modeling and calculation analysis

[0012] Modeling and calculation are performed by using the design software of steel structure and space structure, and through software calculation and analysis, all net rack members and high-strength bolt internal forces, net rack deflection and overall stability meet the requirements during the construction process of the floor net rack jacking, and the jacking equipment is located at the second floor concrete floor part; the second floor floor thickness is 120mm, the column section is 600*600mm, the maximum concentrated load of the jacking frame is 101KN, and the floor needs to be disposed by joist after checking to transfer the load to the beam stress, and a back-up steel pipe is used to back up to ensure that the beam is not deformed due to load;

[0013] b. Net rack floor assembly

[0014] The assembly of the lower chord of the net rack starts from the center, expands the longitudinal and horizontal axes, and corrects the size at any time; the net rack is composed of a plurality of small assembly units, each small assembly unit is provided with a ball and four rods, and forms a four-pyramid, and the small assembly units are combined into a middle assembly unit, and then the middle assembly unit is combined into a net rack; the lower chord ball position of the lower chord node is offset by 2mm;

[0015] c. Setting a plurality of joist frames

[0016] According to the calculation, a plurality of joist frames are arranged on the structural beam, each joist frame comprises two wooden bars, the two wooden bars are arranged in parallel and spaced apart on the concrete beam of the concrete floor, the upper part of the parallel wooden bars is provided with two H-shaped steel beams, the upper part of the two H-shaped steel beams is provided with a steel plate, the center of the upper part of the steel plate supports the jacking frame, the top surface of the jacking frame is provided with a jacking pipe supporting the upper jacking node, and the height of the jacking pipe is 300mm;

[0017] d. Setting a back-up steel pipe

[0018] The back-up steel pipe is provided with a back-up point, the back-up point is located below the H-shaped steel beam, one back-up steel pipe is arranged at each jacking point, the back-up steel pipe supports the H-shaped steel beam bottom for back-up, the bottom end of the back-up steel pipe supports the base bottom surface, and the back-up steel pipes are fixed by angle steel welding to ensure the overall horizontal stability.

[0019] e、Synchronous jacking of the net rack

[0020] The jacking equipment is composed of jacks, pump stations, jacking frames and computer control systems, and the hydraulic jacks are controlled by computers to be synchronously jacked, one displacement sensor is arranged on each jack, and the displacement sensor transmits the data of the piston rising of each jack to the computer in real time during the jacking process, the computer analyzes and compares the received data, if a jacking point is higher than the set range, the computer will stop the work of the jack, and wait until the height is below the lower limit of the set range to work again, so that the height error of the jacking point in the whole jacking process is always kept within the set range.

[0021] f、Sealing and supplementing the rod to complete the installation of the net rack

[0022] After the net rack is jacked into position, the connecting rod members are supplemented and connected with the supports, and the sealing and supplementing of the rod completes the installation of the net rack.

[0023] g、Net rack installation finishing and unloading

[0024] The net rack installation finishing and unloading is implemented in a segmented synchronous unloading mode, and the jacks are controlled by the computer to be synchronously recovered and unloading, and when the arch ring force of the net rack is formed, the support beam frame and the back-up steel pipe are removed.

[0025] The floor net rack jacking construction method of the present application can also adopt the following technical measures to further realize it.

[0026] The aforementioned method, wherein the steel structure and spatial structure design software is 3D3S Design 2022.

[0027] The aforementioned method, wherein the distance between the two lower balls of the tetrahedron is allowed to have an error of ±3mm.

[0028] The aforementioned method, wherein the position offset of the lower chord ball of the net rack is allowed to be 2mm.

[0029] The aforementioned method, wherein the deviation value of the length direction and the width direction of the net rack should not be greater than ±2mm.

[0030] The aforementioned method, wherein the net rack is a bolt ball node net rack.

[0031] The aforementioned method, wherein the two H-shaped steel beams are two H350*240*6*8 steel beams, and the distance between the two steel beams is 1m.

[0032] The method, wherein the jacking frame is provided with several square steel frames stacked up and down, the height of the square steel frame is 500 mm, and M-shaped support rods are arranged between the horizontal beams of the upper and lower frames.

[0033] The method, wherein the center point of the jacking frame is arranged directly below the lower chord ball, or the position of the joist frame is adjusted.

[0034] After the technical scheme is used, the floor space truss jacking construction method has the following advantages:

[0035] 1. The material is simple, the method is simple and applicable, the involved steel beams, steel pipes and batten materials are basically available on site, and can be recycled and used. If not available on site, the steel beams and steel pipes can also be rented.

[0036] 2. The construction is fast and convenient, the joist beam installation construction only needs to measure the point position and place it according to the point position, and the lower backstop can also be installed according to the axis point position and the steel pipe backstop.

[0037] 3. Labor is saved and the construction period is shortened: since the full-frame scaffold erection backstop is cancelled, a large amount of labor is saved, and the construction period is shortened:

[0038] 4. Safe and reliable, economical and applicable: occupies less space, does not conflict with other civil specialties, simultaneously transmits the load to the foundation beam column, is safe and reliable, and has low construction cost.

[0039] 5. Reliable quality, practice has proved that there is no influence on the floor structure during the steel net rack jacking process, and there is no quality risk. BRIEF DESCRIPTION OF DRAWINGS

[0040] Figure 1 It is a schematic diagram of the joist frame structure of the embodiment of the application.

[0041] Figure 2 It is Figure 1 A-A sectional view.

[0042] In the figure: 1 concrete beam, 2 first H-shaped steel, 3 jacking point, 4 second H-shaped steel, 5 steel plate, 6 backstop steel pipe, 7 batten, 8 jacking frame, 9 floor slab, 10 foundation bottom surface. DETAILED DESCRIPTION

[0043] The application will be further described below in combination with the embodiments and their accompanying drawings. EMBODIMENT

[0044] The floor space truss jacking construction method of the application comprises the following construction steps:

[0045] Step one: software modeling, calculation analysis, use 3D3S Design 2022.1 software to model calculation, through software calculation analysis, in the process of jacking construction, all rod and high strength bolt internal force value, net rack deflection, overall stability meet the requirements, jacking equipment in two layer concrete floor slab 9 parts. Two floor slab thickness 120mm, column section 600*600mm, the maximum concentrated load of jacking frame is 101KN, after checking, the floor needs to be handled with joist to transfer the load to the beam stress, at the same time, in order to ensure that the beam is not deformed due to load, steel pipe is used for back jacking.

[0046] Step two: net rack floor assembly, in order to reduce the accumulated error of net rack in the process of assembly, the assembly of net rack lower chord should start from the center, expand the assembly longitudinal and horizontal axis, correct the size at any time, and consider that there is no error when it can be expanded from the center to the surrounding, which requires that the diagonal line (small unit) (the net rack is composed of many small net rack assembly units, and the small assembly unit is a ball four bar (tetrahedron), and then the small assembly unit is composed of middle assembly unit, and then the net rack is assembled. The distance between the two balls at the bottom of the cone is the diagonal line) allows error of ±3mm, the offset of lower chord node (i.e. the position of lower chord ball) is 2mm, the deviation value of overall longitudinal and horizontal (the length direction and width direction of the whole net rack) should not be greater than ±2mm. The whole net rack assembly process is as follows:

[0047] Please refer to Figure 1 And Figure 2 , Figure 1 The joist frame structure of the embodiment of the application. Step three: the joist frame relies on the existing structure beam, and the support frame is arranged on the structure beam, which is mainly composed of steel plate, second H-shaped steel 4, batten and back jacking steel pipe. Because it is installed on the floor, the back jacking steel pipe is arranged to transfer the load to the ground foundation beam. The 100*100*6000mm batten 7 is placed on the concrete beam 1 on both sides of the jacking point along the beam span direction.

[0048] Step four: erect two H350*240*6*8 first H-shaped steel 2 beams on the batten 7.

[0049] Step five: lay 1500*1500*20mm thick steel plate 5 in the middle of the steel beam.

[0050] Step six: place the jacking frame in the middle of the steel plate 5, and the center point of the jacking frame needs to be located directly below the bolt ball, otherwise the position of the joist frame needs to be adjusted.

[0051] Step seven: In order to ensure that the beam does not produce micro cracks, the measure of setting back steel pipe under the beam is taken. The back-up point is located below the H-shaped steel beam, and each back-up steel pipe 6 is arranged at each jacking point, and the back-up steel pipe 6 is supported between the floor slab 9 and the bottom surface 10 of the foundation. The back-up steel pipe with a diameter of 114*6mm is supported on the bottom of the H-shaped steel beam for back-up, and the back-up steel pipes are fixed by angle steel welding to ensure the overall horizontal stability.

[0052] Step eight: Synchronous jacking of the net rack: the jacking equipment is composed of a jack (not shown in the figure), a pump station, a jacking frame and a computer control system.

[0053] The computer-controlled synchronous jacking of the hydraulic jack is used, and the principle of the hydraulic jacking control is that a displacement sensor is arranged for each jack, and the displacement sensor transmits the data of the piston rising of each jack to the computer in real time during the jacking process. The computer analyzes and compares the received data, and when all the data are within the set range, each jack works normally, and if a jacking point is higher than the set range, the computer will stop the work of the jack and wait until the height is within the lower limit of the set range. The height error of each jacking point 3 during the whole jacking process is always kept within the set range.

[0054] Step nine: Edge sealing and rod supplementing, after the net rack is jacked into position, the connecting rod of the support is supplemented.

[0055] Step ten: segmented synchronous unloading, the computer terminal controls the jacks to perform synchronous recovery and synchronous unloading, and when the net rack itself forms an arched ring force, the support beam frame and the back-up steel pipe are removed.

[0056] The support beam frame construction method of the present application mainly refers to converting the original floor force into a foundation beam force by using the H-shaped steel beam support frame, transmitting the vertical load to the foundation beam downward, and ensuring the safety of the structure.

[0057] The method mainly uses the support beam frame construction method in the floor net rack jacking to solve the vertical load force transmitted during the net rack jacking process, transmits the load to the floor concrete beam through the support beam frame, and transmits the vertical load to the bottom plate foundation beam through the back-up support under the beam. The safety risks such as floor cracking and beam cracking are avoided, the difficulties in the construction process are solved, and the method is economical and applicable with low cost.

[0058] The present application has substantial features and significant technical progress, the floor net rack jacking of the present application uses the construction method of joist frame, solves the problem that most of the net rack bolt ball jacking points are located on the floor surface during the assembly process of the floor net rack, and the thickness of the floor surface is only 120mm, which cannot bear the vertical load transmitted by the net rack structure during jacking, the present floor net rack jacking uses the conversion construction method of joist frame to solve the vertical load force transmitted during the jacking process of the net rack, the load is transmitted to the floor concrete beam through the joist frame, and the vertical load is transmitted to the bottom plate foundation beam through the reverse jacking support under the beam. Avoid the safety risks of floor cracking, beam cracking and other risks, solve the difficulties in the construction process, and it is economical and applicable, and the cost is low.

[0059] The above examples are only for illustrating the present application, and are not limited to the present application. Those skilled in the art can make various transformations or changes without departing from the spirit and scope of the present application. Therefore, all equivalent technical solutions should belong to the scope of the present application, which should be defined by the claims.

Claims

1. A construction method for floor grid jacking using joist rack, characterized in that The method comprises the following steps: a. Software modeling and calculation analysis The software modeling and calculation are performed by using the steel structure and spatial structure design software. In the floor truss jacking construction process, the internal force values of all truss members and high-strength bolts, the truss deflection, and the overall stability all meet the requirements. The jacking equipment is located at the two-story floor concrete floor part. The two-story floor concrete floor thickness is 120 mm, the column section is 600*600 mm, and the maximum concentrated load of the jacking frame is 101 KN. After checking, the floor needs to be disposed by supporting beams to transfer the load to the beam stress. At the same time, in order to ensure that the beam is not deformed due to the load, a back-up steel pipe is used for back-up; b. Truss floor assembly The assembly of the lower chord of the truss starts from the center and expands the longitudinal and transverse axes, and the size is corrected at any time. The truss is composed of multiple small truss assembly units. The small assembly unit is provided with a ball and four rods, and is in the form of a square pyramid. The small assembly unit is composed of a middle assembly unit, and the middle assembly unit is finally assembled into a truss. The lower chord ball position offset of the lower chord node is 2 mm; c. Setting a plurality of supporting beam frames According to the calculation, a plurality of supporting beam frames are arranged on the structure beam. Each supporting beam frame comprises two wooden bars which are arranged in parallel and spaced apart on the concrete beam of the concrete floor. The upper part of the parallel wooden bars is provided with two H-shaped steel beams. The upper part of the two H-shaped steel beams is provided with a steel plate. The center of the upper part of the steel plate supports the jacking frame. The top end surface of the jacking frame is provided with a jacking pipe which supports the upper jacking node. The height of the jacking pipe is 300 mm; d. Setting a back-up steel pipe The back-up steel pipe is provided with a back-up point. The back-up point is located below the H-shaped steel beam. Each jacking point is provided with a back-up steel pipe. The back-up steel pipe is used to support the bottom of the H-shaped steel beam for back-up. The bottom end of the back-up steel pipe is supported on the bottom surface of the foundation. The back-up steel pipes are fixed by angle steel welding to ensure the overall horizontal stability; e. Synchronous jacking of the truss The jacking equipment is composed of a jack, a pump station, a jacking frame, and a computer control system. The hydraulic jack is used for computer control synchronous jacking. One displacement sensor is arranged on each jack. The displacement sensor transmits the data of the piston rising of each jack to the computer in real time during the jacking process. The computer analyzes and compares the received data. If the height of a jacking point is higher than the set range, the computer will stop the work of the jack and wait until the height is within the lower limit of the set range to work again. The height error of the jacking point in the whole jacking process is always kept within the set range; f. Edge sealing and rod supplementing to complete the truss installation After the truss is jacked into position, the connecting rod of the support is supplemented, and the edge sealing and rod supplementing are completed to complete the truss installation; g. Truss installation and unloading The truss installation and unloading are implemented by segmental synchronous unloading. The computer terminal controls the jacks to perform synchronous recovery and synchronous unloading. When the truss itself forms an arch ring force, the supporting beam frame and the back-up steel pipe are removed.

2. The construction method of claim 1, wherein the construction method is characterized by, The steel structure and spatial structure design software is 3D3S Design 2022.

3. The construction method of claim 1, wherein the construction method is characterized by, The distance between the two balls at the lower part of the square pyramid allows an error of ±3 mm.

4. The construction method of claim 1, wherein the construction method is characterized by, The truss lower chord ball position offset allows an error of 2 mm.

5. The construction method of claim 1, wherein the construction method is characterized by, The length direction and width direction deviation value of the truss should not be greater than ±2 mm.

6. The construction method of claim 1, wherein the construction method is characterized by, The truss is a bolt ball node truss.

7. The construction method of claim 1, wherein the construction method is characterized by, The two H-shaped steel beams are two H350*240*6*8 steel beams, and the distance between the two steel beams is 1m.

8. The construction method of claim 1, wherein the construction method is characterized by, The jacking frame is provided with a plurality of square steel frames stacked up and down, the height of the square steel frame is 500mm, and M-shaped support rods are arranged between the horizontal beams of the upper and lower frames.

9. The construction method of claim 1, wherein the construction method is characterized by, The center point of the jacking frame is arranged directly below the lower chord ball, otherwise the position of the joist frame is adjusted.

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