Final answer:
Purlins are small beams that provide additional support to structures like roofs or bridges. They help distribute weight evenly across multiple support beams, reducing the risk of structural damage.
Step-by-step explanation:
In physics, purlins can be thought of as small beams that run under the midpoint of all rafters. Purlins are typically used in construction to provide additional support to a structure, such as a roof or bridge.
For example, in a bridge like the Nandu River Iron Bridge shown in Figure 14.1.1, purlins may be used to distribute the weight of the bridge evenly across multiple support beams. This helps prevent excessive stress and strain on individual beams, reducing the risk of structural damage.
Understanding the role of purlins in structures is important as it allows engineers and architects to design safe and stable buildings and bridges.