Steel structural engineering installations connect individual steel members to form a stable structural system. During the construction of the steel structure project in Heilongjiang, some special projects such as waterworks, large-scale shopping malls, lighting roofs, swimming pools, boiler rooms and other steel structure engineering installations are to connect a single steel member to form a stable structural system. During the construction of the steel structure project in Heilongjiang, some special projects such as waterworks, large-scale shopping malls, lighting roofs, swimming pools, boiler rooms, etc., due to the use of functional requirements, equipment or other structures under the roof and surrounding areas, cannot be carried out with traditional lifting schemes. The hoisting operation of the roof steel structure project has certain limitations on the working radius and the limit lifting capacity of the tower crane. Special construction techniques are required to complete the installation of such special steel structure engineering.
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â…£.Technical datas:
The slip construction method is one of the methods to solve such special situations. The slip method has scaffolding slip and track slip. Scaffolding slip refers to using the scaffolding platform as the local working surface for construction, eliminating the disadvantages of high-altitude installation and component bulking, and achieving the large-area installation of the structure sub-area by sliding the scaffolding platform. Objective: This type of construction method is suitable for large-span steel grids and pipe truss steel structures with flat terrain, low construction height and large construction area; the track slip is relatively more flexible and suitable for the above-mentioned complex environment. Unaffected by the height, it is the most effective way to effectively solve the construction of the steel structure at the top of the mixed building group, and the operation cost is low and the safety factor is high. This paper focuses on the track slip construction method with the help of the boiler structure steel structure project of Suifenhe National Forest Wood City in Heilongjiang Province.
Project Description:
Suifenhe National Forest Wood City Boiler House Surface Steel Structure Project, the main structure is steel roof truss, totaling 9 榀, span 15 meters, steel truss spacing 7 meters. The steel roof truss is a triangular truss (as shown in Figure 1 below), the steel truss support is 16.7 meters high, and the steel truss is 2750mm high.
figure 1
Due to the completion of the surrounding civil structure during the construction of the steel roof truss (see the distribution map of the construction site), the lifting operation of the crane cannot be carried out at the periphery, and the boiler in the area below the steel roof truss has been installed (see Figure 2), and it cannot be installed by the crane. Orbital slip method construction.
Overall construction ideas:
Because of the inconvenient crane operation around the construction area of ​​the steel structure project, the air track slip method is adopted. Taking the stud head beam as the working plane, laying the track on the upper part of the ring beam, the slip trolley is installed at the bottom of the support, and each two truss truss is combined into one stable solid system at one end of the construction area (within the working radius of the crane), and then applied Traction or pushing force causes the steel roof truss to slide along the track to a predetermined position. Finally, the track and the sliding trolley are removed to allow the support and the embedded parts to be installed. The construction sequence is that the assembly position is at the 8--9 axis position (the construction area is suitable for the end of the station crane). The 1---2 shaft steel roof truss is assembled first, and then the 3--4 shaft is installed after the position, then 5---6 axis, then 7----8 axis, the last 9 axes can be installed in situ.
Construction preparation:
1. Carefully survey the site before construction and arrange material tools and equipment reasonably. As shown in the above construction site layout plan, the 5.2-meter elevation platform on the east side is used as the temporary stacking site for the angle steel roof truss. If the crane operation position is shown, the angle steel roof truss can be hung to the 16.7-meter elevation of the roof ring beam. At the same time, the purlins, substructures, rails and other components can be hung to the roofs on both sides of the roof;
2. Clean the embedded parts on the roof ring beam, and lay the No. 6 channel steel on the top of the ring beam as the sliding track and level and strengthen it. Control the distance between the two sides of the track and pop the axis of the horizontal and vertical axis. Convenient steel frame in place;
3. Make four sets of slippery trolleys with load-bearing bearings (as shown below);
4. Prepare 50*5 angle steel as temporary support reinforcement to ensure the stability of the slip frame;
5. The operators on both sides are in place, prepare tools such as crowbars, check whether the car is welded firmly, check whether the track is reinforced and solid, and clean up the debris in the track;
6. Clean the gable embedded parts and prepare the temporary angled angle steel support. When the first steel frame is hoisted in place, fix the steel frame with the temporary support of angle steel;
7. Prepare the wire rope plumb, suspended in the middle of the steel roof truss to facilitate the correction of the steel roof truss;
Construction begins:
1. Lift the 8-axis steel roof truss to the roof, calibrate it in place, ensure that the steel frame is vertical, and then connect the steel roof truss with the angle steel and the gable. After hoisting the 9-axis steel roof truss to the 2-axis position, the two truss roof trusses are assembled into a stable solid system with purlins, horizontal supports and vertical supports. (as shown below)
2. Install the sliding trolley, install the sliding trolley made of bearing bearing on the support of the steel frame, then fall in the track, adjust the double-side trolley and temporarily fix it at the bottom of the support (as shown below)
3, the slip begins, the position of each sliding trolley on both sides is one or two people, and the trolley is used to move the trolley forward. Because the span of the project is small, the friction of the steel frame and the load bearing bearing is small. Therefore, the resistance to the forward is not large, and the manpower can be promoted. If the component is heavy, the span is large and the hoist is used for traction or the jack is used for the top. The specific situation is analyzed. The slip process is as follows
4. Slide to the 9-8 axis position, align the axis, remove the trolley and the track, and let the steel frame be installed in place. The remaining three groups sequentially slide the member to a predetermined position in a secondary manner. The secondary structure and support are installed in sequence.
to sum up:
The sliding method has the advantages of convenient installation, low cost and quick effect, and effectively solves the problem that the crane has no working surface in the traditional steel structure engineering construction scheme. In the construction process, we must pay attention to a few problems: 1. The track plane must be flattened, otherwise the sliding resistance is too large after the component is up; 2. The track must be reinforced firmly, and the two sides are unevenly stressed during the sliding process. When the track produces lateral compression force, the track deviates from the preset axis. If the serious track falls below the ring beam surface, the overall structure will fall and an accident occurs. 3. The bilateral force must be uniform during the slip process, and the structure must be guaranteed. The overall synchronization slips forward, and if the force is uneven, the structure will generate torque, which will seriously cause structural deformation. At the same time, the uneven bearing on both sides of the slip and the track will produce a large friction, affecting the slip speed and quality. 4. When the structural span is large, the sliding traction sometimes needs to use a winch or a jack. When using mechanical external force to do traction, we must pay attention to the simultaneous advancement of both sides. Set the observer to observe the track while sliding forward. Stop the slip check to troubleshoot. 5. The slip speed should not be too fast. The hoist of the hoist should be equipped with a reducer or with the pulley block. 6. Tracks and trolleys are available in various forms. They can be used with load-bearing bearings or railcars, or as hangers. They are selected according to the structural form of the components and the actual situation on site. 7. When the heavy structure slips, it is necessary to check the strength of the ring beam. The ring beam with the ring beam strength is not thick and needs to be supported and strengthened.
The above is a summary of our company's installation process in Heilongjiang Steel Structure Project. The pictures are real photos of the steel structure construction of Suifenhe National Forest Wood City in Heilongjiang. Please ask the majority of steel structure engineering practitioners to correct me!
For more exciting content, please pay attention to Heilongjiang Zhongjie Steel Structure Engineering Co., Ltd.**
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