What is the best method to lift a long girder?

What is the best method to lift a long girder?

• A. One crane with a balance beam
• B. A crane with a jib
• C. Two cranes with tag lines
• D. A single hoist

Answer: (A)

Lifting a long girder safely hinges on keeping the load level and distributing the lifting force along the length of the member. A balance beam (spreader beam) attached to one crane does exactly that: it connects to the girder at multiple points along its length, so the crane’s hoist supports the load through a distributed lift rather than at a single point. This reduces the bending stress on the girder, minimizes end swing and twisting, and helps maintain a level, controllable lift as the girder rises. Using a crane with a jib doesn’t address the problem of load distribution along the length, so it’s not as effective for keeping the girder stable during the lift. Two cranes with tag lines add coordination complexity and risk; while tag lines can help control orientation, they don’t inherently prevent the load from bowing or tilting as a long member is hoisted. A single hoist would create a high bending moment at the point of lift and can cause significant bowing or twisting. So, the best method is one crane with a balance beam because it provides distributed support, keeps the girder level, and offers better control throughout the lift.

Lifting a long girder safely hinges on keeping the load level and distributing the lifting force along the length of the member. A balance beam (spreader beam) attached to one crane does exactly that: it connects to the girder at multiple points along its length, so the crane’s hoist supports the load through a distributed lift rather than at a single point. This reduces the bending stress on the girder, minimizes end swing and twisting, and helps maintain a level, controllable lift as the girder rises.

Using a crane with a jib doesn’t address the problem of load distribution along the length, so it’s not as effective for keeping the girder stable during the lift. Two cranes with tag lines add coordination complexity and risk; while tag lines can help control orientation, they don’t inherently prevent the load from bowing or tilting as a long member is hoisted. A single hoist would create a high bending moment at the point of lift and can cause significant bowing or twisting.

So, the best method is one crane with a balance beam because it provides distributed support, keeps the girder level, and offers better control throughout the lift.