Which material is commonly used as a counterweight in cranes?

Steel is commonly used as a counterweight in cranes due to its high density, durability, and ability to withstand the forces experienced during lifting operations. The strength of steel allows for a compact weight that can effectively balance the load being lifted, ensuring the stability of the crane. This is critical in preventing tipping and maintaining proper crane operation.

Wood, while sometimes used in temporary structures or lighter applications, does not provide the necessary weight or stability required for heavy lifting in cranes. Concrete, although heavy and sometimes used in some crane designs, is less common than steel because of its bulkiness and the difficulty in handling large concrete forms. Aluminum, being much lighter than steel, would not offer sufficient counterbalance for the loads cranes typically handle, making it an impractical choice for this application.