A π beam prefabrication construction process

Abstract

The present invention relates to a π beam prefabrication construction process, which belongs to the technical field of bridge construction, and comprises the following steps: production of prefabricated beams, in which concrete is mixed by a concrete mixer in a prefabrication yard, and cast into shape by a formwork system; during the casting process, a vibration motor is used for vibrating to ensure that the concrete is dense and free of bubbles; after the casting is completed, a curing treatment is performed; step two: a mobile positioning device is installed on any beam cap, and the cap beam area is divided into installation areas from the far end to the near end, wherein the installation areas are divided into N, N1, N2, N n ; Step three: transportation and hoisting; use a special transport vehicle to transport the prefabricated beams to the construction site and perform hoisting operations; Step four: on-site installation and connection. At the construction site, remove the mobile positioning device and connect the π beam to the cap beam. The mobile positioning device coordinates with the crane at the bottom of the π beam to adjust the installation posture of the π beam, which can increase the stability of the π beam during the installation process and improve the installation efficiency and accuracy.

Description

Technical Field

[0001] The invention belongs to the technical field of bridge construction, and in particular relates to a π beam prefabrication construction process. Background Art

[0002] The prefabrication method is suitable for the construction of various types of steel beam bridges, various deep-sea docks, cable-stayed bridges, suspension bridges and other projects that require large-span structures. It has a very wide range of applications and is suitable for construction at sea, in water and under complex urban terrain conditions. The construction process is not restricted by weather and various objective conditions, and it is easy to keep the construction site clean and safe.

[0003] In the construction of existing elevated stations and bridges, π-shaped beams are widely used due to their stable structure and strong bearing capacity. However, the traditional π-shaped beam construction process mostly adopts the method of on-site casting, which has problems such as long construction period, large on-site workload, difficult quality control, and great impact on the surrounding environment. These problems are particularly prominent in construction in city centers or busy traffic areas.

[0004] The π-type bridge deck beam is a beam type with a cross-sectional shape similar to π. It is characterized by a large lateral width and a small number of longitudinal wet joints. This design allows the bridge deck to be paved directly on the top plate, thus saving a lot of construction time.

[0005] In the existing prefabricated π beam lifting process, a single crane is often used as the main lifting tool. Although the crane plays an important role in lifting and moving prefabricated π beams, the special shape and weight distribution of the π beams make it easy for problems such as low stability and difficult adjustment to occur during the lifting process. Specifically, when a single crane is used for lifting, due to the uneven weight distribution of the π beam, it is difficult for the crane to maintain the stability of the beam during the lifting process. At the same time, when adjusting the position and direction of the π beam during the lifting process, the operating flexibility of a single crane is limited, and it is difficult to meet the needs of high-precision adjustment.

[0006] Therefore, there is an urgent need for a construction process that can simply and efficiently adjust the direction and position during the hoisting and installation of prefabricated π beams. Summary of the invention

[0007] In order to solve the above problems existing in the prior art, the present invention provides a π-beam prefabrication construction process to solve the problems that the position and direction of the existing prefabricated π-beams are difficult to adjust during hoisting and installation, and the placement efficiency is low.

[0008] The purpose of the present invention can be achieved through the following technical solutions:

[0009] A π beam prefabrication construction process, comprising:

[0010] Step 1: Production of precast beams: In the precast yard, concrete is mixed with a concrete mixer and cast into shape through a formwork system. During the casting process, a vibration motor is used to vibrate to ensure that the concrete is dense and free of bubbles. After casting, curing is carried out.

[0011] Step 2: Install a mobile positioning device on any beam cap, and divide the cap beam area into installation areas from far to near, where the installation areas are divided into N, N1, N2, and Nn;

[0012] Step 3: Transportation and hoisting: Use a special transport vehicle to transport the prefabricated beams to the construction site and perform hoisting operations;

[0013] S301: Determine the lifting device adjustment point and lift the π beam to the top of the N zone;

[0014] S302: moving the movable positioning devices at both ends of the π beam to the N zone, and lifting the movable positioning devices toward the π beam to attract the π beam;

[0015] S303: The mobile positioning device and the lifting device are lowered simultaneously to place the π beam;

[0016] S304: Move the mobile positioning device to the N1 area to carry out the hoisting and installation of the next π beam;

[0017] S305: repeat steps S301-S303 until the π beam is installed;

[0018] Step 4: On-site installation and connection. At the construction site, remove the mobile positioning device and connect the π beam and the cap beam.

[0019] Preferably, iron blocks are installed at both ends of the π beam, and the iron blocks are flush with the ends of the π beam.

[0020] Preferably, the mobile positioning device includes a guide rail, a lifting platform and two magnetic blocks; the guide rail is detachably installed in the middle part of the cap beam, the lifting platform moves horizontally on the guide rail, the two magnetic blocks are symmetrically arranged on the lifting platform and rotate vertically with the lifting platform; the magnetic poles of the two magnetic blocks are in the same direction.

[0021] Preferably, it also includes a positioning system, which is used to position the π beam. The positioning system includes a reader, a main control unit and a lifting platform control unit; a placement point for the π beam is set on the cap beam, and an RFID tag is attached to the placement point. The reader is set on the lifting platform and is used to read the RFID tag; the reader uploads the tag information to the main control unit, and the main control unit sends instructions to the lifting platform control unit according to the information uploaded by the reader.

[0022] Preferably, two RFID tags are correspondingly arranged at each π beam placement point, one tag is marked as the left side, and the other tag is marked as the right side.

[0023] Preferably, in step 1, the π beam is made by prestressing using a pre-tensioning method, which specifically includes the following steps:

[0024] S101: Build the tensioning table and clean the table surface and release agent;

[0025] S102: Fabrication and placement of prestressed tendons and steel reinforcement skeleton;

[0026] S103: Install the formwork, make and trim the formwork, and then apply a release agent on the inner side of the formwork;

[0027] S104: Adjust the initial stress and tension the prestressed tendons before pouring concrete into the formwork;

[0028] S105: Remove the formwork, spray cure and roughen the formed π beam, relax the prestressed tendons and cut them off, and stack and store the π beam after it is out of the groove.

[0029] Preferably, the π-beam pedestal foundation is composed of an end expansion foundation and a straight segment foundation, which are cast in two steps.

[0030] Preferably, in step 3, the transportation of the π beam includes:

[0031] S311: Place sleepers at the fulcrum of the π beam on the transport vehicle, and use a gantry crane to hoist the π beam onto the transport vehicle;

[0032] S312: The hand chain hoist fixes both ends of the beam body. One end of the hand chain hoist is fixed to the clamping ring at the end of the transport vehicle's supporting beam, and the other end is fixed to the steel rope tied to the π beam wing plate. Tighten the hand chain hoist on both sides to fix the π beam.

[0033] The beneficial effects of the present invention are:

[0034] When the π beam deviates from the predetermined position in the installation area, the mobile positioning device coordinates with the crane at the bottom of the π beam to change the position of the π beam and adjust its direction in a small range, which can increase the stability of the π beam during the installation process and improve the installation efficiency and accuracy of the π beam. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to facilitate understanding by those skilled in the art, the present invention is further described below with reference to the accompanying drawings.

[0036] Figure 1 A schematic diagram of the installation structure of a mobile positioning device provided in one embodiment of the present invention;

[0037] Figure 2 A schematic diagram of a π-beam transport fixing structure provided in one embodiment of the present invention;

[0038] Legend: 1. Cap beam; 2. π beam; 3. Mobile positioning device; 31. Guide rail; 32. Lifting platform; 33. Magnetic block; 4. Iron block. DETAILED DESCRIPTION

[0039] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the specific implementation methods, structures, features and effects of the present invention are described in detail below in conjunction with the accompanying drawings and preferred embodiments.

[0040] like Figure 1-Figure 2 As shown, a π beam prefabrication construction process includes:

[0041] Step 1: Production of precast beams: In the precast yard, concrete is mixed with a concrete mixer and cast into shape through a formwork system. During the casting process, a vibration motor is used to vibrate to ensure that the concrete is dense and free of bubbles. After casting, curing is carried out.

[0042] Step 2: Install the mobile positioning device 3 on any beam cap 1, and divide the cap beam 1 area into installation areas from far to near, where the installation areas are divided into N, N1, N2, N n ; The cap beam 1 area is divided into installation areas for each π beam 2, so that the hoisting work can be carried out in an orderly manner. The installation is carried out from the far end to the near end, which is conducive to the operation of the mobile positioning device 3. During the entire hoisting and installation process, the mobile positioning device 3 only needs to be moved gradually from the far end to the near end, and will not affect the installed π beams 2 during the hoisting process; at the same time, the mobile positioning device 3 is installed on the cap beam 1, and can cooperate with the crane on the cap beam 1 to complete the positioning, storage and position and direction adjustment of the π beam 2.

[0043] Step 3: Transportation and hoisting: Use a special transport vehicle to transport the prefabricated beams to the construction site and perform hoisting operations;

[0044] S301: Determine the adjustment point of the hoisting device, and hoist the π beam 2 to the air above the N area; accurately determining the adjustment point of the hoisting device can ensure the stability and safety during the hoisting process and prevent the π beam 2 from tilting or being damaged during the hoisting process.

[0045] S302: Move the mobile positioning devices 3 at both ends of the π beam 2 to the N area, so that both ends of the installation area have mobile positioning devices 3 to support the π beam 2 at the bottom, and lift the mobile positioning device 3 toward the π beam 2 to attract the π beam 2; by attracting and fixing the π beam 2 with the mobile positioning device 3, the stability and accuracy of the lifting process can be further ensured, and the deviation caused by factors such as wind and vibration can be reduced; in addition, the mobile positioning devices 3 at both ends support the π beam 2 from the bottom, avoiding the use of the crane as a single lifting device, and the π beam 2 is lifted to the installation site. When the π beam 2 is suspended in the air above area N, since the π beam 2 suspended in the air deviates from the predetermined position, it is difficult to achieve accurate and efficient position adjustment relying solely on the action of the crane. Therefore, the present application utilizes a mobile positioning device 3 to support the bottom of the π beam 2 and a crane to suspend the π beam 2 in the air. The two work together. When the π beam 2 deviates from the predetermined position in the installation area, the mobile positioning device 3 coordinates with the crane to change the position of the π beam 2 and adjust the direction in a small range, which can increase the stability of the π beam 2 during the installation process and improve the installation efficiency and accuracy of the π beam 2.

[0046] S303: The mobile positioning device 3 and the lifting device descend simultaneously to place the π beam 2; the synchronous descent can ensure that the π beam 2 is placed stably and accurately at the predetermined position to avoid impact or damage to the cap beam 1 or other structures; when the mobile positioning device 3 rises, it generates suction on the π beam 2 above the installation point, and the crane also pulls the π beam 2. When suction is generated between the mobile positioning device 3 and the π beam 2, it is necessary to monitor the force between the two at all times to ensure that the π beam 2 can be quickly placed in a balanced state.

[0047] S304: Move the mobile positioning device 3 to the N1 area to hoist and install the next π beam 2; quickly move the positioning device 3 to the next installation area to prepare for the next round of hoisting operations, thereby achieving a continuous and efficient construction process.

[0048] S305: Repeat steps S301-S303 until the π beam 2 is installed; the standardized and repeated operation process can ensure the installation quality and efficiency of each π beam 2, while reducing the risk of human error.

[0049] Step 4: On-site installation and connection. At the construction site, remove the mobile positioning device 3 and connect the π beam 2 and the cap beam 1. After removing the mobile positioning device 3 at the construction site, accurately connect the π beam 2 and the cap beam 1 to ensure the stability and safety of the entire structure. Strict quality inspection and control are required during the on-site connection process to ensure that the connection quality meets the design requirements. After the connection between the π beam 2 and the cap beam 1 is completed, the main construction of this section of the bridge structure is completed, laying the foundation for subsequent construction, such as bridge deck paving, installation of ancillary facilities, etc.

[0050] In one embodiment, iron blocks 4 are installed at both ends of the π beam 2, and the iron blocks 4 are flush with the ends of the π beam 2. The mobile positioning device 3 includes a guide rail 31, a lifting platform 32 and two magnetic blocks 33; the guide rail 31 is detachably installed in the middle of the cap beam 1, and the lifting platform 32 moves horizontally on the guide rail 31. The two magnetic blocks 33 are symmetrically arranged on the lifting platform 32 and rotate in the vertical direction of the lifting platform 32; the lifting platform 32 should be equipped with a driving mechanism (such as a motor, a reducer, etc.) to realize automatic control of its horizontal movement. Two magnetic blocks 33 are symmetrically arranged on the lifting platform 32. Under normal conditions, the two magnetic blocks 33 should be horizontal with the cap beam 1 to ensure that they can generate attraction with the iron block 4. , generating a supporting force for the π beam 2 from the bottom; and when the lifting platform 32 descends to place the π beam to the specified position, the lifting platform 32 needs to move to the next installation area, i.e. N1. Since the two magnetic blocks are opposite to the magnetic poles of the iron block 4 at this time, they have a stronger suction force. Therefore, in order to avoid the magnetic block 33 from affecting the π beam 2 during the movement, the two magnetic forces need to be rotated from the horizontal state to the vertical state before moving, and the magnetic pole direction of the magnetic block 33 is changed. When the lifting platform 32 drives the magnetic block 33 to move, the suction effect between the magnetic block 33 and the iron block 4 is reduced, so that the movement of the lifting platform 32 requires less power and reduces the impact on the installed π beam 2 during the movement.

[0051] In one embodiment, the magnetic poles of the two magnetic blocks 33 are in the same direction, ensuring that the magnetic poles of the two magnetic blocks 33 are in the same direction, so that when they contact the iron block 4 at the end of the π beam 2, a strong attraction force can be generated to ensure the stability of the π beam 2 during the lifting process.

[0052] In one embodiment, it also includes a positioning system, which is used to position the π beam 2. The positioning system includes a reader, a main control unit and a lifting platform 32 control unit; a placement point for the π beam 2 is set on the cap beam 1, and an RFID tag is attached to the placement point. The reader is set on the lifting platform 32 for reading the RFID tag; the reader uploads the tag information to the main control unit, and the main control unit sends instructions to the lifting platform 32 control unit according to the information uploaded by the reader. At each π beam 2 placement point of the cap beam 1, a unique RFID tag is pre-attached, and the tag contains the location information of the placement point and the model of the π beam 2; a reader is installed on the lifting platform 32 of the mobile positioning device 3, and when the lifting platform 32 moves on the guide rail 31, the RFID tag information at the position of the π beam 2 placement point is automatically scanned and read by the reader during the movement, so as to realize the position positioning of the lifting platform, and then the lifting platform rises at the currently scanned positioning point, ready to produce an adsorption effect on the π beam 2. After the adsorption force is produced on the π beam 2, the lifting platform 32 directly descends to guide the π beam 2 to accurately reach the placement point; Among them, the reader uploads the read RFID tag information to the main control unit by wireless or wired means. The main control unit, as the core of the entire positioning system, is responsible for receiving and processing this information; the main control unit sends a control instruction to the control unit of the lifting platform 32 according to the calculation results; after receiving the instruction, the control unit of the lifting platform 32 drives the lifting platform 32 to move horizontally to the specified position on the guide rail 31, and adjusts the lifting height so that the magnetic block 33 is aligned with the iron block 4 at the end of the π beam 2 and attracts; after the magnetic block 33 and the π beam 2 are attracted stably, the lifting equipment begins to descend and steadily places the π beam 2 at the specified position of the cap beam 1. Subsequently, the lifting platform 32 and the magnetic block 33 can release the π beam 2 and move to the next placement point for the next round of lifting operations.

[0053] In one embodiment, two RFID tags are provided corresponding to each placement point of the π beam 2, one of which is marked on the left and the other is marked on the right. This makes the movement of the lift on the guide rail 31 more precise. When one of the RFID tags is scanned, the information of the tag can be obtained and a judgment can be made as to whether the current movement should be forward or backward, so that the scanning of the two RFID tags can be realized, thereby achieving fast and accurate positioning of the lift platform 32.

[0054] In one embodiment, in step 1, the π beam 2 is made by prestressing using a pre-tensioning method, which specifically includes the following steps:

[0055] S101: Build a tensioning table and clean the tabletop and isolation agent; Build a stable tensioning table to ensure that it can withstand the tensioning force of the prestressed tendons. Clean the tabletop and apply isolation agent to prevent the prestressed tendons from sticking to the tabletop, which is convenient for subsequent operations;

[0056] S102: Prestressed tendons and steel skeletons are manufactured and placed; Prestressed tendons and steel skeletons are manufactured according to design requirements and accurately placed on the tensioning table. This step is the key to ensuring the structural strength of π beam 2 and uniform distribution of prestress;

[0057] S103: Install the formwork, make and trim the formwork, and apply an isolating agent on the inside of the formwork; install the formwork to form the outer shape of the π beam 2, and apply an isolating agent on the inside of the formwork to prevent the concrete from sticking to the formwork. The making and trimming of the formwork must be precise to ensure that the size and shape of the π beam 2 meet the design requirements;

[0058] S104: After adjusting the initial stress and tensioning the prestressed tendons, pour concrete into the formwork; after adjusting the initial stress to the design value, tension the prestressed tendons to a predetermined stress level and maintain this state, then pour concrete into the formwork to fill the gap between the prestressed tendons and the steel skeleton. The concrete needs to be fully vibrated during the pouring process to ensure density and uniformity;

[0059] S105: Remove the formwork, spray cure the formed π beam 2, and roughen it, relax the prestressed tendons and cut them off, and stack and store the π beam 2 after it comes out of the slot; after the concrete reaches a certain strength (usually determined according to the design requirements and the concrete strength development curve), remove the formwork; spray cure the formed π beam 2 to promote the hardening and strength development of the concrete; at the same time, roughen the surface of the π beam 2 to increase the adhesion of the subsequent connection or decorative layer; finally, relax the prestressed tendons and cut off the excess parts to make the π beam 2 obtain a stable prestressed state, and the π beam 2 after coming out of the slot needs to be properly stacked and stored to avoid damage.

[0060] In one embodiment, the foundation of the π beam 2 beam pedestal is composed of an end expansion foundation and a straight segment foundation, which are cast in two steps; first, a foundation pit is excavated at a designated location according to the design requirements, and a steel mesh is laid. Then, concrete is poured into the foundation pit, and vibrators and other tools are used to vibrate the concrete to ensure that the concrete is dense and free of bubbles. After the concrete has initially set, necessary maintenance is performed; after the end expansion foundation is cast, wait for it to reach sufficient strength (generally more than 75% of the design strength). Then, a steel mesh is laid on the straight segment foundation, and concrete is poured into it for vibration. Similarly, necessary maintenance is performed after the concrete has initially set; the end expansion foundation is used to increase the bearing area of ​​the foundation and improve the stability of the foundation; the straight segment foundation directly supports the π beam 2 to ensure its stable horizontal position.

[0061] In one embodiment, in step 3, the transportation of the π beam 2 includes:

[0062] S311: Place sleepers at the fulcrum of π beam 2 on the transport vehicle, and use a gantry crane to lift π beam 2 onto the transport vehicle; first, select a transport vehicle that is suitable for the size, weight and transportation distance of π beam 2, and ensure that it is in good working condition. Place sleepers in advance at the fulcrum of π beam 2 of the transport vehicle (i.e., the position on the vehicle used to support π beam 2) to reduce the friction between π beam 2 and the transport vehicle, and protect π beam 2 from damage; use a gantry crane (or other lifting equipment) to lift π beam 2 steadily from the ground or storage rack. During the lifting process, ensure that the lifting ropes or steel cables are firmly tied to the lifting points of π beam 2 to avoid slippage or tilting during the lifting process. When π beam 2 is lifted above the transport vehicle, it should be lowered slowly to ensure that π beam 2 is accurately and steadily placed on the sleepers of the transport vehicle.

[0063] S312: The hand chain hoist is used to fix the two ends of the beam body. One end of the hand chain hoist is fixed to the clamp ring at the end of the supporting beam of the transport vehicle, and the other end is fixed to the steel rope tied to the wing plate of the π beam 2. The hand chain hoist is tightened on both sides to fix the π beam 2. In order to prevent the π beam 2 from moving or overturning due to bumps or sudden braking during transportation, a hand chain hoist is required for reinforcement. The specific method is: fix one end of the hand chain hoist to the clamp ring at the end of the supporting beam of the transport vehicle, and the other end is fixed to the wing plate of the π beam 2 by binding steel ropes. The hand chain hoist needs to be installed on both sides, and ensure that the tension of the chain hoists on both sides is balanced, so that the π beam 2 is firmly fixed on the transport vehicle; after the hand chain hoist is fixed, it is necessary to manually tighten the chain to ensure that the π beam 2 is firmly fixed on the transport vehicle. At the same time, the entire fixing device should be fully inspected to ensure that all connection points are firm and reliable, without looseness or slippage. In addition, it is necessary to check whether the contact surface between the π beam 2 and the transport vehicle is flat and free of foreign matter to avoid unnecessary friction or damage during transportation.

[0064] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technical personnel in this field can make some changes or modify the technical contents disclosed above into equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any brief modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A π beam prefabrication construction process, characterized in that: include Step 1: Production of precast beams: In the precast yard, concrete is mixed with a concrete mixer and cast into shape through a formwork system. During the casting process, a vibration motor is used to vibrate to ensure that the concrete is dense and free of bubbles. After casting, curing is carried out. Step 2: Install a mobile positioning device on any cap beam, and divide the cap beam area into installation areas from far to near, where the installation areas are divided into N, N1, N2, and Nn; Step 3: Transportation and hoisting: Use a special transport vehicle to transport the prefabricated beams to the construction site and perform hoisting operations; S301: Determine the lifting point of the lifting equipment and lift the π beam to the top of the N area; S302: moving the movable positioning devices at both ends of the π beam to the N zone, and lifting the movable positioning devices toward the π beam to attract the π beam; S303: The mobile positioning device and the lifting device are lowered simultaneously to place the π beam; S304: Move the mobile positioning device to the N1 area to carry out the hoisting and installation of the next π beam; S305: repeat steps S301-S303 until the π beam is installed; Step 4: On-site installation and connection: at the construction site, dismantle the mobile positioning device and connect the π beam and the cap beam; Iron blocks are installed at both ends of the π beam, and the iron blocks are flush with the ends of the π beam. The mobile positioning device includes a guide rail, a lifting platform and two magnetic blocks; the guide rail is detachably installed in the middle of the cap beam, and the lifting platform moves horizontally on the guide rail. The two magnetic blocks are symmetrically arranged on the lifting platform and rotate vertically with the lifting platform; the magnetic poles of the two magnetic blocks are in the same direction; When the π beam deviates from the predetermined position in the installation area, the mobile positioning device coordinates with the crane to change the position of the π beam and adjust its direction in a small range.

2. A π beam prefabrication construction process according to claim 1, characterized in that: It also includes a positioning system, which is used to position the π beam. The positioning system includes a reader, a main control unit and a lifting platform control unit; a placement point for the π beam is set on the cap beam, and an RFID tag is attached to the placement point. The reader is set on the lifting platform and is used to read the RFID tag; the reader uploads the tag information to the main control unit, and the main control unit sends instructions to the lifting platform control unit according to the information uploaded by the reader.

3. A π beam prefabrication construction process according to claim 1, characterized in that: Two RFID tags are correspondingly set at each π beam placement point, one tag is marked as the left side, and the other tag is marked as the right side.

4. A π beam prefabrication construction process according to claim 1, characterized in that: In the step 1, the π beam is made by prestressing using the pre-tensioning method, which specifically includes the following steps: S101: Build the tensioning table and clean the table surface and release agent; S102: Fabrication and placement of prestressed tendons and steel reinforcement skeleton; S103: Install the formwork, make and trim the formwork, and then apply a release agent on the inner side of the formwork; S104: Adjust the initial stress and tension the prestressed tendons before pouring concrete into the formwork; S105: Remove the formwork, spray cure and roughen the formed π beam, relax the prestressed tendons and cut them off, and stack and store the π beam after it is out of the groove.

5. A π beam prefabrication construction process according to claim 4, characterized in that: The π beam pedestal foundation consists of an end expansion foundation and a straight segment foundation, which is cast in two steps.

6. A π beam prefabrication construction process according to claim 1, characterized in that: In step 3, the transportation of the π beam includes: S311: Place sleepers at the fulcrum of the π beam on the transport vehicle, and use a gantry crane to hoist the π beam onto the transport vehicle; S312: The hand chain hoist fixes both ends of the beam body. One end of the hand chain hoist is fixed to the clamping ring at the end of the transport vehicle's supporting beam, and the other end is fixed to the steel rope tied to the π beam wing plate. Tighten the hand chain hoist on both sides to fix the π beam.

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