When a building is being designed, and a crane or guy derrick will have to be used, how is the building modified to accommodate the extra weight of the crane or derrick?

When a building is being designed, and a crane or guy derrick will have to be used, how is the building modified to accommodate the extra weight of the crane or derrick?

• A. Floor slabs are thickened
• B. Columns are made stronger
• C. Windows are reinforced
• D. Roof trusses are shortened

Answer: (B)

A crane or derrick adds a heavy, concentrated vertical load that travels through the building’s load path to the foundation. To handle that extra demand, the structure is modified where the load is carried most directly—the columns and their foundations. Strengthening the columns (using larger, stronger sections or additional columns and reinforced connections) increases the axial and moment capacity of the frame at the crane location, ensuring the crane load and any dynamic forces from operating the crane stay within design limits. Thickening floor slabs wouldn’t directly increase the capacity of the load path to resist the crane’s concentrated load, reinforcing windows doesn’t address the frame’s ability to carry vertical and moment loads, and shortening roof trusses would actually reduce capacity rather than provide the necessary support.

A crane or derrick adds a heavy, concentrated vertical load that travels through the building’s load path to the foundation. To handle that extra demand, the structure is modified where the load is carried most directly—the columns and their foundations. Strengthening the columns (using larger, stronger sections or additional columns and reinforced connections) increases the axial and moment capacity of the frame at the crane location, ensuring the crane load and any dynamic forces from operating the crane stay within design limits.

Thickening floor slabs wouldn’t directly increase the capacity of the load path to resist the crane’s concentrated load, reinforcing windows doesn’t address the frame’s ability to carry vertical and moment loads, and shortening roof trusses would actually reduce capacity rather than provide the necessary support.