The big outdoor Ferris wheel is basically a permanent amusement facility. Therefore, in the Ferris wheel design, it is not only necessary to comply with the relevant specifications of architectural structure, but also the relevant specifications of amusement facilities. The following analysis from Zhejiang Juma Amusement Equipment is carried out by taking a large Ferris wheel as an example:
According to the regulations, when the wind speed is less than 15m/s, the round wheel ride can operate normally, and it should be designed according to the normal operation state. The design method adopts the allowable stress method and the safety factor of the structure. The important shaft, pin shaft, and important welding seam and the design method should be greater than or equal to 6, and the other parts should be greater than or equal to 4.
According to the regulations, the dynamic load coefficient of 1.3 should be considered for the movable part structure in this state. When the wind speed is greater than 15m / s, the big Ferris wheel is closed, and the design should be carried out according to the limit state. The structural design under a limit state should be in accordance with the Code for Design of Steel Structures (GB 50017-2003) and other relevant current codes.
The maximum wind speed of the outdoor Ferris wheel construction site is 31m /s (once-in-a-century). The seismic fortification intensity is 7 degrees, and the design basic seismic acceleration value is 0.15g. Designing earthquake is grouped into the first group, the seismic structural measures are carried out at 8 degrees design, the site category is class Ⅲ.
In addition to the conventional architectural analysis, the structural strength analysis is also needed in Ferris wheel design. Structural strength analysis is divided into two categories: normal operation and limit condition. Considering the dynamic coefficient of the wheel during normal operation, the standard combination of all possible load conditions is carried out, and the components are checked according to the allowable stress method. The limit state design method is used to check the structure stress under the limit condition. The wheel disc of the Ferris wheel is a prestressed structure, which is affected by the prestressing force in the cable, and the tire is in compression state. The control factor that determines the state of the wheel disc is the prestress of the cable, and the stability of the wheel disc determines the feasibility of the wheel disc design.
The outdoor Ferris wheel is a kind of special building, so it is very important to select the design method carefully, to be careful in the analysis process, and to be true and reliable for the results.