A crane can only lift as high a load as its main wheel allows. This maximum wheel load depends on several factors. The rated capacity load of course matters, but an impact allowance factor determines its significance. The other factors are the weight of the crane overall and the weight of the trolley and hoist assembly. Besides the crane's load, use the maximum wheel load to choose the crane's other components, such as its beam size.
Divide the crane's weight, measured in pounds, by 2. If the crane weight is 6,000 pounds: 6,000 / 2 = 3,000.
Add the weight of the hoist and trolley, also measured in pounds. If they weigh 2,500 pounds combined: 3,000 + 2,500 = 5,500.
Multiply the rated capacity load weight by the impact allowance factor. If the former is 10,000 pounds and the latter s 1.2: 10,000 x 1.2 = 12,000.
Add the answers from steps 2 and 3: 5,500 + 12,000 = 17,500.
Divide your answer by 2: 17,500 / 2 = 8,750 pounds. This answer is the crane's maximum load.
- "Design of Steel Structures"; Duggal; 2009
- American Crane & Host: Runway Beam Size Selection