Large-span steel structure truss construction method based on three-dimensional scanning

Abstract

The invention relates to a large-span steel structure truss construction method based on three-dimensional scanning. The method comprises the following steps: surveying and setting out; pre-embedded bolts are installed; adjusting the position; pouring concrete; positioning and scanning the positions of the embedded bolts; manufacturing a truss jig frame; assembling a steel structure truss; finely adjusting and welding the steel structure truss; hoisting the steel structure truss; and connecting the steel structure trusses. According to the method, the unmanned aerial vehicle and the three-dimensional scanner are adopted for accurately positioning the column top embedded bolts, the column top embedded bolts are scanned again after concrete column pouring is completed to determine the final position coordinates, the accurate span and the bolt distance are calculated, and the large-span steel structure truss structure is assembled in a segmented mode on the basis of the accurate span value. And the splicing length and the reserved welding deformation are determined, the overall size precision after the truss is spliced is guaranteed, and it can be guaranteed that the truss structure is smoothly in place during hoisting. The assembling precision of the large-span steel structure truss can be improved, the modification work is reduced, the installation progress is accelerated, and the engineering quality is guaranteed.

Description

TECHNICAL FIELD

[0001] The present application relates to a construction method of a large-span truss, in particular to a construction method of a large-span steel structure truss based on three-dimensional scanning. BACKGROUND

[0002] The existing large-span steel structure truss is generally manufactured in a processing plant, transported to the site for assembly into a whole, and then hoisted as a whole. The steel structure truss and the concrete column are processed and constructed according to the design size. Since the steel structure truss has a large span, it is generally transported in multiple sections for ease of transportation, and then assembled on site before hoisting. However, the welding amount is relatively large during the on-site assembly process, and the resulting deformation is also relatively large. When hoisted as a whole, the overall deviation is large. At the same time, the concrete column and the connecting bolts embedded at the top thereof will also produce errors and deviations during the pouring construction process. The steel structure truss often has deviations in position when connected with the column top connecting bolts during installation, and thus has to be reamed during the installation process, which affects the installation progress, installation quality, and cost. SUMMARY

[0003] The purpose of the present application is to provide a construction method of a large-span steel structure truss based on three-dimensional scanning, so as to solve the problem of large deviation of the position of the column top connecting bolt when the existing large-span steel structure truss is installed, which affects the installation progress, installation quality, and cost.

[0004] The present application is implemented as follows: A construction method of a large-span steel structure truss based on three-dimensional scanning, comprising the following steps.

[0005] a. Measurement and line laying: Accurately laying a line on the concrete column top formwork or reinforcement according to the design drawing, and marking the center position of the embedded bolt.

[0006] b. Embedded bolt installation: Installing the embedded bolt at the top of the concrete column.

[0007] c. Position adjustment: Using a drone to carry a three-dimensional scanner to detect the position of the embedded bolt, and fine-tuning the position of the embedded bolt according to the detected deviation value.

[0008] d. Concrete pouring: Pouring the concrete column, and monitoring the bolt position and perpendicularity throughout the pouring process, stopping pouring and correcting immediately upon finding a deviation.

[0009] e. Positioning scanning of embedded bolt position: After the concrete column construction is completed, using a drone to carry a three-dimensional scanner to perform positioning scanning of the position of the embedded bolt again, to determine the deviation of the actual position of the embedded bolt from the initial position, and record and save the position deviation of each embedded bolt as a positioning basis for truss assembly.

[0010] f. Truss jig fabrication: Fabricate the truss jig of the large-span steel structure truss at the construction site.

[0011] g. Steel structure truss assembly: Assemble the steel structure truss transported in sections to the construction site on the jig.

[0012] h. Steel structure truss fine adjustment and welding: According to the position deviation of each embedded bolt determined in step e, control and adjust the position of each control node, and after adjusting each control node to be accurate, perform spot welding fixation. After the spot welding positioning node is reviewed correctly, formal welding can be performed.

[0013] i. Steel structure truss hoisting: Hoist the steel structure truss onto the concrete column and fix the steel structure truss through the embedded bolts.

[0014] j. Steel structure truss connection: Install the subsequent steel structure trusses in sequence, and install the roof tie rods and supports between the adjacent two steel structure trusses, and complete the construction of the entire steel structure truss.

[0015] Further, in step b, a bolt fixing frame is arranged on the upper part of the reserved section of the concrete column top, the bolt fixing frame does not contact the column formwork or steel bars, and the embedded bolt is fixed on the bolt fixing frame through a nut.

[0016] Further, in step c, the position of the embedded bolt is adjusted and corrected by adjusting the bolt fixing frame or adding a gasket at the bottom of the embedded bolt.

[0017] Further, in step d, the position and perpendicularity of the embedded bolt are monitored throughout the pouring process, and the position and perpendicularity of the embedded bolt are reviewed once every 30 cm of pouring height. If a deviation is found, pouring is stopped immediately and corrected to ensure that the final position meets the design requirements. The axis position, elevation and perpendicularity of the bolt are reviewed again before the initial setting and final setting of the concrete.

[0018] Further, in step g, the truss members are laid flat on the jig for assembly, and the plan size and camber value of the truss are ensured to meet the design requirements through measurement and adjustment; in step i, after the steel structure truss is assembled, the steel structure truss is turned over and erected using a turning equipment.

[0019] Further, in step i, the steel structure truss is hoisted using the double-machine lifting method within the span.

[0020] Further, in step j, after the first steel structure truss is hoisted and fixed firmly with the ground anchor, the second steel structure truss is installed. After the second steel structure truss is hoisted, the hoisting crane does not disengage, and the other crane installs the roof tie rods and supports. The subsequent steel structure trusses are installed and connected in sequence.

[0021] Further, the unmanned aerial vehicle carries a three-dimensional scanner to fly along a predetermined route, and obtain a three-dimensional model of the building structure, and determine the position of the embedded bolt in the three-dimensional model.

[0022] The present application adopts an unmanned aerial vehicle + three-dimensional scanner to accurately position the embedded bolt at the top of the column during the construction of the concrete column, and scans the embedded bolt at the top of the column again to determine the final position coordinates after the concrete column is poured, calculates the accurate span and bolt spacing, and determines the assembly length and reserved welding deformation based on the accurate span value when the segmented truss structure of the large-span steel structure is assembled, so as to ensure that the overall dimensional error of the truss after assembly reaches “millimeter level”, and the truss structure can be smoothly positioned during hoisting. The present application can improve the assembly accuracy of the large-span steel structure truss, reduce the modification work, speed up the installation progress, and ensure the engineering quality. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 is a flowchart of the construction method of the large-span steel structure truss based on three-dimensional scanning of the present application. DETAILED DESCRIPTION

[0024] The technical solutions of the present application will be described clearly and completely below in combination with the drawings. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0025] In the description of the present application, it should be noted that the orientations or positional relationships indicated by the terms “center”, “upper”, “lower”, “left”, “right”, “vertical”, “horizontal”, “inner”, “outer” and the like are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application. In addition, the terms “first”, “second”, “third” and the like are only for description purposes, and cannot be understood as indicating or implying relative importance.

[0026] As shown in Figure 1 A construction method of a large-span steel structure truss based on three-dimensional scanning of the present application, specifically comprising the following steps.

[0027] a. Measurement and line laying: accurately pop a line on the concrete column top formwork or reinforcement according to the design drawing, and mark the center position of the embedded bolt. Adopt a total station or a level to calibrate the axis deviation (≤2mm) and the elevation error (±5mm), to ensure that the bolt positioning meets the equipment installation requirements.

[0028] b. Embedded bolt installation: install the embedded bolt at the top of the concrete column.

[0029] A bolt fixing bracket is installed on the upper part of the reserved section at the top of the concrete column. The bolt fixing bracket does not contact the column formwork or reinforcing steel. The pre-embedded bolts are fixed to the bolt fixing bracket with nuts. The bolt fixing bracket is made of angle steel or reinforcing steel and is fixed separately to the concrete surface, without contacting the column formwork or reinforcing steel, to prevent the pre-embedded bolts from shifting during concrete pouring. The bolt fixing bracket must have sufficient rigidity to avoid welding deformation affecting positioning accuracy. The pre-embedded bolts are initially fixed to the crossbeam of the bolt fixing bracket with nuts.

[0030] c. Position adjustment: Use a drone carrying a 3D scanner to locate and detect the pre-embedded bolts, and fine-tune the position of the pre-embedded bolts according to the detected deviation value.

[0031] A drone carrying a 3D scanner flies along a predetermined route to obtain a 3D model of the building structure, and then determines the location of the embedded bolts within the 3D model. The combination of a drone and a 3D scanner enables rapid scanning, measurement, and positioning of large building structures. The point cloud obtained from the 3D scan is processed to obtain a 3D model of the building structure, allowing for accurate determination of the embedded bolt positions. 3D scanning technology enables rapid and accurate positioning of embedded bolts at column tops, improving measurement efficiency.

[0032] When fixing, first control the verticality of the pre-embedded bolts: During installation, use a plumb bob or straightedge to check the verticality of the bolts, and control the deviation to be ≤1 / 1000 and the total length to be ≤10mm. It can be corrected by adjusting the bolt fixing bracket or adding shims to the bottom of the pre-embedded bolts; high-strength bolts (such as M20 and above) need to be temporarily fixed with double nuts to prevent loosening.

[0033] d. Concrete pouring: Pour concrete columns and monitor the bolt position and verticality throughout the pouring process. If any deviation is found, stop pouring immediately and correct it.

[0034] When pouring concrete at the top of the column, pour the concrete symmetrically from all sides of the pre-embedded bolts to avoid impact from one side causing the pre-embedded bolts to shift; the vibrator should be at least 10cm away from the bolts, and direct collision with the bolts or supports is strictly prohibited to prevent displacement of the pre-embedded bolts.

[0035] Throughout the pouring process, the position and verticality of the bolts are monitored. The position is checked every 30cm of pouring height. If any deviation is found, the pouring is stopped immediately and the deviation is corrected to ensure that the final position meets the design requirements.

[0036] After the initial setting and before the final setting of the concrete, the axial position, elevation and verticality of the embedded bolts should be checked again. If the deviation exceeds the limit, it should be adjusted before the concrete strength reaches 1.2MPa. After the final setting, clean the laitance and debris on the embedded threads and check the integrity of the embedded threads.

[0037] e. Embedded bolt position positioning scanning: After the concrete column construction is completed, the unmanned aerial vehicle carries a three-dimensional scanner to perform positioning scanning on the position of the embedded bolt again, to determine the deviation of the actual position of the embedded bolt from the initial position, and to record and save the position deviation of each embedded bolt as the positioning basis for truss assembly.

[0038] The accurate span and bolt spacing are calculated according to the actual positions of the embedded bolts, and the positioning is performed according to the same in the subsequent steel structure truss assembly and welding process.

[0039] f. Truss jig making: The jig for the large-span steel structure truss is made on the construction site.

[0040] The jig is set on the ground, and the height and spacing of the jig are designed according to the steel structure truss and the span to ensure the stability of the steel structure truss during assembly.

[0041] g. Steel structure truss assembly: The steel structure truss transported in sections to the construction site is assembled on the jig.

[0042] The truss members are laid flat on the jig for assembly, and the planar dimensions, camber value, etc. of the truss are ensured to meet the design requirements through measurement and adjustment. For large-span trusses, the camber value is determined according to the design requirements and construction simulation results, and pre-cambering is achieved through the jig or jack to compensate for the deflection deformation during installation.

[0043] When assembling, first hoist the chord, position it with the jig positioning block, ensure the centerline, levelness, and end surface perpendicularity, and then install the web of the truss. First install the middle section of the truss, then expand to both sides, and fix each chord to the support jig pressing plate. Install the web from the center.

[0044] h. Steel structure truss fine adjustment and welding: According to the position deviation of each embedded bolt determined in step e, control and adjust the position of each control node, and then perform spot welding after each control node is accurately adjusted. After the spot-welded positioning nodes are reviewed and corrected, formal welding can be performed.

[0045] When adjusting, first adjust and fix the planar projection coordinate position with a laser theodolite and a steel tape, then control and adjust the height difference of each control node with a level, and then determine the node position with a scribing, positioning template, and intersecting surface. After each control node is accurately adjusted, spot welding is performed. After the spot-welded positioning nodes are reviewed and corrected, formal welding can be performed. When adjusting the node coordinates, the influence of welding deformation should be considered.

[0046] After assembly is completed, the truss is turned over and erected using a turning equipment, and then hoisted to the design position using hoisting equipment.

[0047] In order to ensure the installation precision of the truss and whether the assembly precision requirement is reached, the measurement of the steel truss is carried out before hoisting, and all the positioning blocks must be removed during the measurement so as to measure the truss in a free state, thereby ensuring the correctness and rapidity of hoisting in place.

[0048] i. Hoisting of the steel truss: the steel truss is hoisted and placed on the concrete column, and the steel truss is fixed through the embedded bolt.

[0049] After the axis elevation and the embedded bolt of the concrete column foundation are checked and qualified, the center line is placed on the column head of the concrete column before the installation of the steel truss. After ensuring the assembly accuracy of the steel truss, the steel truss is hoisted and placed on the concrete column by using the double-machine lifting method in the span, and the nut is installed and tightened on the embedded bolt.

[0050] j. Connection of the steel truss: the subsequent steel trusses are installed in sequence, and the roof tie rod and support are installed between the adjacent two steel trusses, and the construction of the whole steel truss is completed.

[0051] After the first steel truss is hoisted and fixed with the ground anchor, the second steel truss is installed. After the second steel truss is hoisted, the hoisting crane is not unhooked, and the other crane installs the roof tie rod and support; the subsequent steel trusses are installed and connected in sequence.

[0052] The above embodiments are only used to illustrate the technical solutions of the present application, but not to limit it; although the present application is described in detail with reference to the above embodiments, those skilled in the art should understand that the technical solutions recorded in the above embodiments can be modified, or some or all of the technical features can be replaced by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A construction method for large-span steel trusses based on three-dimensional scanning, characterized in that, Includes the following steps: a. Measurement and layout: Accurately mark the center position of the pre-embedded bolts on the formwork or reinforcing bars at the top of the concrete column according to the design drawings; b. Installation of embedded bolts: Install embedded bolts on the top of the concrete column; c. Position adjustment: Use a drone carrying a 3D scanner to locate and detect the pre-embedded bolts, and fine-tune the position of the pre-embedded bolts according to the detected deviation value; d. Concrete pouring: Pour concrete columns and monitor the bolt position and verticality throughout the pouring process. If any deviation is found, stop pouring immediately and correct it. e. Positioning and scanning of embedded bolts: After the concrete column construction is completed, a drone carrying a 3D scanner is used to scan the position of the embedded bolts again to determine the deviation between the actual position and the initial position of the embedded bolts. The position deviation of each embedded bolt is recorded and saved as the positioning basis for truss assembly. f. Truss frame fabrication: Fabricating a truss frame for a large-span steel structure on the construction site; g. Steel truss assembly: Assembling the steel truss sections transported to the construction site on a jig; h. Fine adjustment and welding of steel truss: Based on the positional deviation of each pre-embedded bolt determined in step e, control and adjust the position of each control node. After adjusting each control node to accuracy, spot welding is performed to fix it. After the spot welding positioning node is verified to be correct, formal welding can be carried out. i. Steel truss hoisting: The steel truss is hoisted and placed on the concrete columns, and then fixed with pre-embedded bolts; j. Steel truss connection: Install the subsequent steel trusses in sequence, and install roof tie rods and supports between adjacent steel trusses to complete the construction of the entire steel truss.

2. The construction method for large-span steel truss based on three-dimensional scanning according to claim 1, characterized in that, In step b, a bolt fixing frame is installed on the upper part of the reserved section at the top of the concrete column. The bolt fixing frame does not contact the column formwork or reinforcing bars, and the pre-embedded bolts are fixed to the bolt fixing frame with nuts.

3. The construction method for large-span steel truss based on three-dimensional scanning according to claim 2, characterized in that, In step c, the position of the embedded bolt is adjusted and corrected by adjusting the bolt fixing bracket or by adding shims to the bottom of the embedded bolt.

4. The construction method for large-span steel truss based on three-dimensional scanning according to claim 1, characterized in that, In step d, the position and verticality of the pre-embedded bolts are monitored throughout the pouring process. The position is checked every 30cm of pouring height. If any deviation is found, the pouring is stopped immediately and the bolts are corrected to ensure that the final position meets the design requirements. After the initial setting of the concrete and before the final setting, the axial position, elevation and verticality of the bolts are checked again.

5. The construction method for large-span steel truss based on three-dimensional scanning according to claim 1, characterized in that, In step g, the truss components are laid flat on the jig for assembly. The planar dimensions and camber of the truss are measured and adjusted to ensure that they meet the design requirements. In step i, after the steel truss is assembled, a turning device is used to turn the steel truss up and stand it upright.

6. The construction method for large-span steel truss based on three-dimensional scanning according to claim 1, characterized in that, In step i, the steel truss is hoisted using the double-machine lifting method within the span.

7. The construction method for large-span steel truss based on three-dimensional scanning according to claim 1, characterized in that, In step j, after the first steel truss is hoisted and firmly fixed to the ground anchor, the second steel truss is installed. After the second steel truss is hoisted, the lifting crane does not detach, and another crane is used to install the roof tie rods and supports. The subsequent steel trusses are then installed and connected in sequence.

8. The construction method for large-span steel truss based on three-dimensional scanning according to claim 1, characterized in that, The drone, carrying a 3D scanner, flies along a predetermined route to obtain a 3D model of the building structure and determines the location of the pre-embedded bolts in the 3D model.

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