What is a beam supported at only one end, but is rigidly held in position at that end called?

A beam supported at only one end and rigidly held in position at that end is referred to as a cantilever beam. This type of beam is designed to extend horizontally from its support and carries loads along its length while resisting bending at the fixed end. The design allows for efficient use of materials since there is no need for supports along its length, freeing up the space below it for various uses.

Cantilever beams can often be seen in structures like balconies, overhangs, or bridges where the conditions require a projection beyond a structure's main support. The rigidity at the fixed end is crucial, as it helps in transferring the load and managing the bending moments that occur due to the beam's structure.

Understanding the characteristics of cantilever beams is essential for those in the fire service, as it influences how fire can spread in a building and affects rescue operations and structural stability concerning fire dynamics. This makes knowledge of such structural elements vital in assessing risks during firefighting operations or building emergencies.