What are reaction forces primarily responsible for in a beam?

Reaction forces are primarily responsible for supporting the beam and maintaining its equilibrium. When a beam is subjected to loads, the reaction forces arise at the supports to counteract these loads, thereby preventing the beam from collapsing. The supports generate these forces in response to the loads exerted on the beam, ensuring that it remains stable and can safely carry the applied weights.

These reaction forces are critical in structural engineering as they help determine how the loads are transferred through the structure. Understanding how reaction forces work allows engineers to design beams that can withstand various load conditions without failure. This fundamental concept is crucial for ensuring the safety and integrity of structures.