What happens to the loading when a lattice boom comes into contact with another surface?

When a lattice boom comes into contact with another surface, the loading typically changes from a compression state to a bending state. This shift occurs because the contact with another surface applies a load that causes the boom to bend rather than simply compress. Lattice booms are designed to carry vertical loads primarily through compression directly along their structure; however, when they encounter an obstacle or another surface, the load distribution changes.

Under standard operating conditions, the forces in a lattice boom are distributed evenly as compressive loads throughout its members. However, upon impacting another surface, elements of the boom are forced to flex due to the new loading conditions. This bending can introduce shear forces and moment forces that weren't present before contact.

By understanding this concept, it becomes clear why recognizing the state of loading is crucial for safe operation and effective engineering design. The awareness of how stresses change in structural members ensures proper precautions are taken to prevent structural failure and maintain safety standards during crane operations.