L68A1 Mast Section Four issues to pay attention to when choosing a tower crane
When building unit chooses tower crane, the first consideration is what kind of tower crane to choose, how to choose? Today, tower crane factory small editor from a professional point of view for you to analyze the selection of tower crane must pay attention to the four factors: tower crane basic parameters, tower crane free height, tower crane installation methods, the impact of the surrounding environment.
1, the determination of the basic parameters of the tower crane
The basic parameters of the tower crane refer to the height, arm length and arm end of the tower crane(ie, the farthest end of the tower crane arm). Except for very special cases, the maximum lifting weight of the tower crane generally does not need to be considered. According to the length, width and height of the building, the length of the tower boom can be initially determined. The arm length is appropriate to ensure that it can cover all projects and have a slight margin.
The tower cranes that are often seen at present are generally 30m, 40m, 50M, 55m, 60m, 70M, and several types. The tower cranes with larger arm lengths are rarely used by other conditions on the scene. Caution is required when selecting. The height of the tower is as long as it is 10 to 15M higher than the maximum Gaodu Gaochu of the building. The weight of the arm end is determined by the weight of the object to be lifted by the civil construction workers. General frame structure type buildings, because the tower crane needs to be lifted concrete bucket, the weight of the arm is larger; Now the concrete structure of the high-rise buildings, this requirement is lower. After the above three parameters are determined, the type of tower crane can be initially determined.
2, the determination of the tower crane installation method
The tower crane is a device used on the ground. Its own weight(1Ot ~ 200t) is much larger than the general construction machinery. Therefore, the installation of the tower crane foundation is also one of the main issues that needs to be considered when selecting. At present, there are three basic installation methods for self-rising tower cranes: fixed feet in large concrete blocks, pressurized weights in large chassis, and walking installation methods. Different installation methods have different requirements for the ground pressure of the basic soil(15-20t / M2, and different types of Tower cranes have different pressure on the ground. In addition, the foundation depth and slope type of the project also affect the installation method of the tower crane foundation. This in turn affects the selection of Tower cranes. This point needs to select a certain amount of practical experience, and carefully read the proposed use of Tower hanging product specifications related to the basic section of the chapter before it can be determined.
3, free height determination
Commonly used self-ascending tower cranes can rise with the elevation of the building. When the height of the tower crane exceeds the "free height", if it rises again, it is necessary to adopt the "attached wall" measure. It is to "anchor" the tower with the project under construction. Different types of Tower cranes have different heights for the first time, and the distance between each "attached wall" is also different. The tower attached wall has an additional lateral tension in the construction, which requires that the completed part of the project can achieve a certain strength. If the construction speed is fast and the attached wall part has not yet reached the scheduled strength, this will affect the construction progress. In this case, consideration should be given to choosing a type of tower crane with a higher free height. And it is particularly important in winter construction.
4, the impact of the surrounding environment
The surrounding environment includes transportation roads, underground pipelines, the height of surrounding buildings, and the presence or absence of high-voltage lines. Tower crane structures are longer and heavier, generally 10m long, and require large transport vehicles and large-tonnage car cranes when installed. After the completion of the project, it will need to be removed with the same equipment. Therefore, the surrounding environment also has a certain restriction on the selection of Tower cranes. Sometimes only one ton of tower can be completed during construction. However, due to the constraints of the surrounding environment, it is necessary to choose two smaller tonnage tower cranes before construction; On the contrary, sometimes only a small tonnage tower crane is required. If you want to solve this problem well, after the preliminary determination of the tower lifting type, you can find a professional tower lifting and assembling unit(which requires the qualifications approved by the local construction committee) to be finalized after on-site investigation.
