3. Normal Manhole:
A normal manhole, also known as a utility hole or maintenance hole, is a covered opening in the street or sidewalk that provides access to underground utilities such as sewer lines, storm drains, or telecommunications infrastructure. Manholes are typically made of cast iron, concrete, or a combination of materials. The main purpose of a manhole is to allow workers to enter the underground infrastructure for inspection, maintenance, or repairs. They are usually round or rectangular and have a removable cover that can be lifted to provide access. The covers are designed to be heavy and secure to prevent unauthorized access and to ensure the safety of pedestrians and vehicles passing over them.
