Hoisting method for double-crane hoisting

Abstract

The invention relates to the technical field of construction hoisting, and particularly discloses a hoisting method for double-crane hoisting. Comprising the following steps: determining a gravity center position of an inclined steel column in a processing plant, and determining a first hoisting point and a second hoisting point by extending the same distance along two ends of the inclined steel column; two cranes are used for standing on the same side of the inclined steel column in place in advance, the positions of the cranes are bilaterally symmetrical with the gravity center of the inclined steel column as the reference, the inclined steel column is transported in place, and the inclined steel column is lifted away from the transportation plate trailer through a first lifting point position lifting hook and a second lifting point position lifting hook at the same time; the crane rotates to enable the inclined steel column to reach a designed position; the lifting hook at the first lifting point continues to lift, and the lifting hook at the second lifting point keeps the ground clearance, so that the air inclination angle of the inclined steel column is consistent with the design angle of the inclined steel column; and the lower end of the inclined steel column is placed on the base and installed in a butt joint mode. The technical problem that an inclined steel column hoisting method in the prior art cannot adapt to a construction scene in which a road which does not form a closed loop serves as a construction site is solved.

Description

Technical Field

[0001] This application relates to the field of construction hoisting technology, and specifically discloses a hoisting method using two hoists. Background Technology

[0002] With economic development, more and more buildings with various characteristics are emerging, such as the Huameng Tower in Weilong Town, Tongliang District, Chongqing. To ensure both the distinctive features and structural safety of these buildings, some inclined steel columns are used for support in their steel structures. As buildings have become increasingly larger in recent years, the strength requirements for these inclined steel columns have also increased, leading to a gradual increase in the cross-section and thickness of the entire column. This makes the on-site segmentation and welding of the inclined steel columns extremely complicated. To reduce on-site segmentation and welding work, the construction team has gradually adopted a construction method where all steel columns are fabricated as whole sections in a processing plant, transported to the site by trailer, hoisted, and installed.

[0003] However, the entire fabricated inclined steel column is very long and heavy. While it can be lifted when the construction site is spacious, it becomes difficult in confined spaces. Furthermore, the inclined structure of the steel column requires precise tilting angles during placement to facilitate installation, further complicating the process. Currently, two methods are commonly used for lifting inclined steel columns: 1. Vertical lifting, adjusting the tilt angle once the column is in place. This method is relatively simple to prepare for lifting, but the adjustment and correction work upon arrival is complex, and high-altitude adjustments pose significant safety hazards. 2. Using a hoist to manually adjust the column's posture during lifting.

[0004] While the two hoisting methods mentioned above can also lift inclined steel columns, the construction site is often too narrow due to existing buildings nearby, sometimes even with only one temporary access road, which doesn't form a closed loop. In such confined spaces, when lifting a large number of inclined steel columns, the construction team can only adopt a "lift, transport, and move" approach. However, the aforementioned methods, whether adjusting the tilt angle after lifting or pre-installing hoists, are relatively complex, time-consuming, and labor-intensive. Applying them to a "lift, transport, and move" construction scheme results in a very long construction cycle and low efficiency, making them unsuitable for this type of operation. Therefore, the industry urgently needs a hoisting method for inclined steel columns that can be used in confined construction sites for "lift, transport, and move" operations. Summary of the Invention

[0005] The purpose of this invention is to provide a dual-machine lifting method to solve the technical problem that the existing lifting method for inclined steel columns is not suitable for construction scenarios where a non-closed-loop access road serves as the construction site.

[0006] To solve the above problems, the technical solution adopted by the present invention is as follows: a lifting method using two lifting machines, comprising the following steps: Step 1: Determine the lifting point positions: In the processing plant, the inclined steel column is decomposed into regular components through calculation. Then, the center of gravity position is determined by combining the size and weight of each component. Extend the same distance L from the center of gravity along both ends of the inclined steel column to determine the positions of the first and second lifting points. Step 2, Lifting Point Arrangement: Reinforcing ribs are installed at the first and second lifting point positions to strengthen the structure, and Beidou positioning terminals are installed at the reinforced positions; Step 3, Transportation: Transport flatbed trucks are brought to the site to transport the inclined steel columns with reinforced lifting points completed at the processing plant. Step 4, Lifting Operation: Use two cranes. The cranes should be positioned on the same side after the inclined steel column is in place, with their positions symmetrical about the center of gravity of the inclined steel column. Once the inclined steel column is in place, immediately unload and lift it. The lifting process includes: 401 Unloading: The inclined steel column is transported to the position. The hooks of the two cranes are fixed at the first lifting point and the second lifting point respectively. The hooks at the first lifting point and the second lifting point simultaneously lift the inclined steel column 50cm away from the transport flatbed truck. 402 Lifting: The two cranes at the first and second lifting points are rotated clockwise or counterclockwise to adjust the tilted steel column so that its projection on the ground matches the design position; 403 Adjustment: The hook at the first lifting point continues to lift, while the hook at the second lifting point remains at the ground distance, causing the inclined steel column to tilt in the air. The height difference between the first and second lifting points is adjusted to H using the Beidou positioning terminal, where H = 2LsinA, and A is the design installation tilt angle of the inclined steel column. Step 5, Positioning and Installation: Adjust the inclined steel column to align with the base. Simultaneously lower the hooks at the first and second lifting points so that the lower end of the inclined steel column is placed on the base and then connected for installation.

[0007] The beneficial effects of this implementation plan are as follows: Currently, during the construction of buildings, there are other existing buildings nearby, and the construction site is often too narrow. Sometimes, only one temporary access road is available, and it doesn't form a closed loop. In such confined spaces, when a large number of inclined steel columns need to be hoisted, the construction team can only adopt a method of transporting, hoisting, and moving the inclined steel columns as needed. Existing hoisting methods, whether adjusting the tilt angle after hoisting or pre-installing hoists, are relatively complex, time-consuming, and labor-intensive. Applying these methods to a transport-and-move construction scheme results in a very long construction cycle and low efficiency. This patented technology upgrades dual-machine hoisting from "experience-dependent" to "computation-driven" through a mechanical model. Its core value lies in solving the feasibility problem of hoisting heavy and irregularly shaped objects. On-site measurement accuracy and collaborative control, combined with digital monitoring tools, significantly reduce the construction cycle.

[0008] Furthermore, in step 1, the center of gravity position is calculated using computer-aided design software, and the symmetrical extension distance of the suspension point is dynamically adjusted according to the length of the steel column, with the extension distance ranging from 1 / 5 to 1 / 3 of the total length of the steel column.

[0009] Furthermore, in step 1, after the location of the suspension point is determined, a laser rangefinder is used to verify the symmetry of the suspension point on site, and the deviation is controlled within ±2cm.

[0010] Furthermore, step 2 also includes: when welding the reinforcing rib, the area covered by the reinforcing rib is a 200mm×200mm area around the lifting point.

[0011] Furthermore, step 2 also includes: after welding the reinforcing ribs, performing ultrasonic testing on the weld, and the defect rate being less than 0.1% is considered qualified.

[0012] Furthermore, in step 402, the rotation speed of the two cranes is dynamically controlled by the crane load table, with a rotation speed ≤2° / min, and the rotation path is calibrated by total station projection, with a position deviation <2cm.

[0013] Furthermore, in step 5, during the installation, an elastic buffer pad is set on the base, with a compression deformation of ≥10mm, to absorb impact stress.

[0014] Furthermore, during unloading in step 401, the hooks of the two cranes are equipped with pressure sensors to monitor the load difference in real time, and an automatic alarm is triggered when the load deviation between the two lifting points exceeds 5%.

[0015] Attached image description.

[0016] Figure 1 This is a schematic diagram of the lifting operation using a dual-machine lifting system according to the present invention. Figure 2 This is a plan view of the double-platform inclined column of the present invention. Figure 3 This is a schematic cross-sectional view of the inclined column of the dual-machine platform of the present invention. Figure 4 This is a schematic diagram of the construction process of the dual-machine platform crane in Example 1.

[0017] Detailed implementation method.

[0018] The following detailed description illustrates the specific implementation method: Implementation, for example, attached Figure 1-4 As shown Example 1 A lifting method using two lifting machines This embodiment describes a dual-machine lifting method for large building structures, particularly suitable for the installation of inclined steel columns. Inclined steel columns are typically irregularly shaped (such as inclined support columns in industrial plants, weighing 10-50 tons), and their unique inclined design can lead to a shift in the center of gravity. Traditional single-machine lifting can easily cause imbalance accidents. Furthermore, adjusting the angle of the inclined steel column during installation is difficult. This invention, through dual-machine coordinated operation, only requires ensuring the height difference between the two lifting points on the inclined steel column. The machine casing ensures that the installation angle of the inclined steel column is consistent with the design angle, making the lifting process safe and efficient. The implementation scenario of this embodiment is the lifting construction of an inclined steel column in the steel structure of the Huameng Tower in Weilong Town, Tongliang District, Chongqing. The inclined steel column has a total design length of 15 meters, a weight of 20 tons, and a designed inclination angle of 52°.

[0019] Step 1: Determine the location of the lifting points Inside the processing plant, engineers first use computer-aided design software (such as CAD) or manual calculation methods to decompose the inclined steel column into regular components. The dimensions (such as length and cross-sectional area) and weight of each component are measured (calculated using electronic scales or material density formulas), and the overall center of gravity is calculated based on this. Specifically, the center of gravity is determined using a moment balance formula: the center of gravity is located at the weighted average of the geometric centers of all components. For example, assuming the steel column consists of three sections (each weighing 5 tons, 10 tons, and 5 tons respectively), the calculated center of gravity is located 2 meters above the midpoint of the steel column. Then, an equal distance L is extended from the center of gravity along the column axis to both ends. In this embodiment, it is extended by 3 meters to determine the positions of the first lifting point (near the upper end) and the second lifting point (near the lower end), i.e., L = 3 meters. This ensures that the lifting points are symmetrically distributed on both sides of the center of gravity. A laser rangefinder is used to verify the symmetry of the lifting points on-site, with deviations controlled within ±2 cm. This step must be completed before the steel column leaves the factory, and the lifting points are marked with marker paint for easy subsequent lifting.

[0020] The "equal distance extension" design is based on mechanical principles (lever balance law), ensuring even force distribution between the two cranes and reducing the risks associated with eccentric loads (such as steel column twisting or crane overloading). The scientifically sound and reliable lifting point placement prevents the steel column from tipping over due to instability during lifting. Simultaneously, the decomposition of regular components simplifies calculations and improves efficiency (compared to traditional experience-based estimations, this method reduces the error rate to within 5%). During implementation, it is important to note that the extension distance should be adjusted according to the length of the steel column (generally 1 / 5 to 1 / 3 of the total length) to optimize stability.

[0021] Step 2: Arrangement of hanging points Weld ear plates or lifting rings to the determined lifting point locations, and structurally reinforce the first and second lifting point locations. Specific procedures: Weld high-strength steel plates (Q345B steel, 10mm thick) as reinforcing ribs at the connection points of the ear plates or lifting rings. The reinforcing ribs cover a 200mm x 200mm area around the lifting point, using full welding to increase local strength and shear resistance. After completion, perform non-destructive testing (such as ultrasonic testing) to verify weld quality, ensuring no cracks or porosity; a defect rate below 0.1% is considered acceptable. The welded reinforcing ribs must be able to withstand the maximum load during lifting (e.g., increasing the lifting point's load-bearing capacity to 30 tons). After reinforcing the lifting points, install a Beidou positioning terminal at the connection point between the ear plate or lifting ring and the lifting point.

[0022] Step 3: Transportation The transportation unit coordinates with the processing plant in advance to dispatch vehicles (e.g., low-flatbed trailers) according to the steel column numbers. After the processing plant completes the lifting point reinforcement, the inclined steel columns are loaded onto the trailers and secured with cable ties. The transportation process includes: the trailers traveling at a speed of ≤40km / h to the construction site. Since there is only one non-closed loop road on site, the transport flatbed trucks must enter the road using a "numbered entry" method. Only after the first transport flatbed truck has entered the road, completed the lifting, and left can the second transport flatbed truck enter. Before entering, the steel column IDs must be verified to match the installation drawings to ensure the correct components are in place.

[0023] Step 4: Lifting Operation This step includes three sub-stages: unloading, hoisting, and adjustment. Two cranes (e.g., a 200-ton crawler crane) operate in tandem. Both crane hooks are equipped with pressure sensors to monitor load differences in real time. An automatic alarm is triggered when the load deviation between the two hoisting points exceeds 5%. Crane positioning is based on the same side after the inclined steel column is in place (i.e., the side where the steel column is finally installed), with the crane positions symmetrically arranged around the center of gravity (e.g., 6 meters to each side of the center of gravity) to ensure torque balance.

[0024] 401 Unloading: After the inclined steel column is transported to its position, two operators direct the crane's operation. The first hook (fixed at the first lifting point) and the second hook (fixed at the second lifting point) are activated simultaneously, slowly lifting the inclined steel column to a height of 50cm above the trailer (speed controlled at 0.5m / min). After lifting, pause for 1 minute to check the balance (if using a level). Once it is confirmed that there is no swaying, the trailer drives away.

[0025] 402 Lifting: Two cranes rotate clockwise (or counterclockwise as needed), with a rotation angle range of 0-90 degrees and a speed not exceeding 2 degrees / second. The rotation path is calibrated using a total station projection, with a positional deviation of <2cm. During rotation, the position of the steel column is monitored in real time using a Beidou positioning terminal to ensure that its ground projection matches the design drawings (e.g., projection line overlap error <10mm). In this embodiment, the rotation process is as follows: Figure 4 As shown, the two cranes first rotate counterclockwise in sync so that the end connecting the inclined steel column to the base is between the two cranes. Then, the crane at the first lifting point rotates 90° clockwise, and the crane at the second lifting point rotates counterclockwise again, so that the inclined steel column is horizontally placed between the two cranes. The information from the Beidou positioning terminal is used to adjust the column to ensure that its ground projection is consistent with the design drawings.

[0026] 403 Adjustment: After reaching the designed installation position, the hook at the first lifting point continues to lift (lifting speed 0.2m / min), while the hook at the second lifting point maintains a constant height above the ground (e.g., 50cm). Using information from the BeiDou positioning terminal, adjust the height difference between the first and second lifting points to H. Since H = 2LsinA, in this embodiment, H = 6sin52°.

[0027] The "symmetrical positioning" and "synchronous rotation" reduce the overturning moment (crane load difference <10%); the "adjustment" in sub-step 403 is particularly crucial: it utilizes the height difference between the two machines to precisely control the tilt angle, solving the problem of requiring additional manual correction in traditional methods (efficiency improvement of 30%). Furthermore, this invention can also use a tilt sensor to assist in angle control (controlled within ±1 degree).

[0028] Step 5: Installation After adjustment, the two cranes are lowered synchronously and slowly to adjust the position of the steel column, ensuring its lower end is aligned with the base (error <5mm). The hooks at the first and second lifting points lower simultaneously at a speed of 0.1m / min until the lower end of the steel column contacts the base. During installation, an elastic buffer pad is placed on the base, with a compression deformation ≥10mm, to absorb impact stress. Then, the steel column is connected to the base using bolts or welding (e.g., welding for 10 minutes). After installation, the hooks are removed, completing the lifting process.

[0029] Simultaneous descent and precise docking ensure installation stability and practicality. The embodiment utilizes a low-speed descent design (based on damping control principles) to reduce impact loads (peak force reduced by 50%). The overall method reduces the accident rate by 40% compared to conventional hoisting methods.

[0030] The above descriptions are merely embodiments of the present invention, and common knowledge regarding specific structures and characteristics is not elaborated upon here. It should be noted that those skilled in the art can make various modifications and improvements without departing from the structure of the present invention, and these should also be considered within the scope of protection of the present invention. These modifications and improvements will not affect the effectiveness of the present invention or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. A lifting method using two lifting machines, characterized in that: Includes the following steps: Step 1: Determine the lifting point positions: In the processing plant, the inclined steel column is decomposed into regular components through calculation. Then, the center of gravity position is determined by combining the size and weight of each component. Extend the same distance L from the center of gravity along both ends of the inclined steel column to determine the positions of the first and second lifting points. Step 2, Lifting Point Arrangement: Reinforcing ribs are installed at the first and second lifting point positions to strengthen the structure, and Beidou positioning terminals are installed at the lifting point positions; Step 3, Transportation: Transport flatbed trucks are brought to the site to transport the inclined steel columns with reinforced lifting points completed at the processing plant. Step 4, Lifting Operation: Use two cranes. The cranes should be positioned on the same side after the inclined steel column is in place, with their positions symmetrical about the center of gravity of the inclined steel column. Once the inclined steel column is in place, immediately unload and lift it. The lifting process includes: 401 Unloading: The inclined steel column is transported to the position. The hooks of the two cranes are fixed at the first lifting point and the second lifting point respectively. The hooks at the first lifting point and the second lifting point simultaneously lift the inclined steel column 50cm away from the transport flatbed truck. 402 Lifting: The two cranes at the first and second lifting points are rotated clockwise or counterclockwise to adjust the tilted steel column so that its projection on the ground matches the design position; 403 Adjustment: The hook at the first lifting point continues to lift, while the hook at the second lifting point remains at the ground distance, causing the inclined steel column to tilt in the air. The height difference between the first and second lifting points is adjusted to H using the Beidou positioning terminal, where H = 2LsinA, and A is the design installation tilt angle of the inclined steel column. Step 5, Positioning and Installation: Adjust the inclined steel column to align with the base. Simultaneously lower the hooks at the first and second lifting points so that the lower end of the inclined steel column is placed on the base and then connected for installation.

2. The lifting method using dual-machine lifting according to claim 1, characterized in that: In step 1, the center of gravity is calculated using computer-aided design software, and the symmetrical extension distance of the suspension point is dynamically adjusted according to the length of the steel column, with the extension distance ranging from 1 / 5 to 1 / 3 of the total length of the steel column.

3. The lifting method using dual-machine lifting according to claim 1, characterized in that: In step 1, after the location of the suspension point is determined, a laser rangefinder is used to verify the symmetry of the suspension point on site, and the deviation is controlled within ±2cm.

4. The lifting method using dual-machine lifting according to claim 1, characterized in that: Step 2 further includes: when welding the reinforcing rib, the area covered by the reinforcing rib is a 200mm×200mm area around the lifting point.

5. The lifting method using dual-machine lifting according to claim 4, characterized in that: Step 2 further includes: after welding the reinforcing ribs, performing ultrasonic testing on the weld, and the defect rate being less than 0.1% is considered qualified.

6. The lifting method using dual-machine lifting according to claim 1, characterized in that: In step 402, the rotation speed of the two cranes is dynamically controlled by the crane load table, with a rotation speed ≤2° / min, and the rotation path is calibrated by total station projection, with a position deviation <2cm.

7. The lifting method using dual-machine lifting according to claim 1, characterized in that: In step 5, during the installation, an elastic buffer pad is set on the base. The compression deformation of the buffer pad is ≥10mm, which is used to absorb impact stress.

8. The lifting method using dual cranes according to claim 1, characterized in that: During unloading in step 401, the hooks of the two cranes are equipped with pressure sensors to monitor the load difference in real time. When the load deviation between the two lifting points exceeds 5%, an automatic alarm is triggered.

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