1. The basic load.
The basic load is the load that always or often acts on Crane structure, including the self-weight load, the lifting load, the inertial horizontal load, and the dynamic load effect that takes into account the dynamic load factor multiplied by the corresponding static load. For some cranes operating with a grab (bin) or an electromagnetic disk, the dynamic load shedding effect of the lifting load should be taken into account due to sudden unloading.
2. Additional load.
The additional load refers to the non-recurrent load of the crane in normal working condition. Including the maximum wind load acting on the structure under working condition of the crane, the lateral force of the crane skew operation, and the temperature load, snow load and some process load, which are determined according to the actual situation.
3. Special load.
Special load refers to the crane when the crane is in the non-working state, the structure may be subject to the maximum load or in the working state of the structure by accidental adverse load. Such as the maximum wind load, the test load, and the installation load, seismic load, and some process loads considered by the actual situation, such as the collision load of the crane in the working condition.
The combination that only consider the basic load is the combinationⅠ, the combination that consider both the basic load and additional load is the combination Ⅱ, the combination that consider both the basic load and special load or three types of load is combinations Ⅲ.
The combination of various loads is the original basis for the calculation of structural strength and stability. The safety factor of strength and stability must meet the requirements of load combination Ⅰ, Ⅱ and Ⅲ, and the fatigue strength is calculated according to load combination Ⅰ.