Manholes are made with an inverted slop to let sewerage flow by gravity in the desired direction. It is installed to perform a variety of functions. They make it possible to access meters that read liquid flows to things like sanitary sewer lines. Also, they allow access to underground cables and telecom facilities. Sometimes, manhole access ports are also called manways. They must be easily accessible and should be located at least 1.0 m clear of any boundary or structure. When choosing manholes and manhole covers, it is important to consider factors like construction, dimension specifications, cover specifications, and features. Keep reading to know how to know more about manholes:
The choice of a suitable location for manholes may impact how the pipes will be aligned. It is important to give at least 1 meter of clearance from the outside diameter of the manhole riser to any boundaries or structures to facilitate maintenance and rescue. Specific requirements subject to individual site characteristics will be determined by the city council.
The location of the manhole and pipelines must reduce interference with future buildings. They should not be located in public land but must be located within common access ways. When installed in residential areas, they should be located within the side, front, and rear yards. Also, when installed in business areas, they must be adjacent to road frontage boundaries.
Manhole materials include precast concrete, plastic, and fiberglass. Plastic manholes are usually made from polyethylene. They have been increasingly used because they are eco-friendly and do not pose a risk of ground contamination. Precast concrete manholes are traditional options that are still used today because of their durability. Finally, fiberglass manholes are made to include a manhole barrel and cover that can be integrated with other accessories and features.
When designing manholes, it is important to focus on creating a segmental, panel or one-unit structures. Generally, manholes are circular, rectangular, or other shapes which satisfy all design requirements. It is necessary to design manholes so that its components’ structural integrity is maintained during installation and service life. Also, during design, the impact of pipe entries on the manhole risers’ structural integrity must be taken into account.
Every manhole must be designed to support all existing and any predicted future dead loads. Also, manholes must be designed to support hydrostatic pressure, lateral earth pressure, and any high eccentric lateral pressure because of surcharge load or live load. Every component of manholes must be designed for an asset life of up to 100 years.