Why are manhole covers designed circularly?

With a circular structure, the top-down force will be dispersed evenly across the surface to help the manhole cover be affected.

Design of circular manhole covers will save more materials.

Going to the street we often encounter a manhole with many shapes such as round, square, rectangular, sometimes triangles to withstand the payload as required. But mainly the circular design, because this structure has many outstanding advantages compared to the other forms.

According to Mr. Nguyen Duc Phuong (Hanoi National University), physically, with a circular structure, the top-down force (caused by a wheel, foot or heavy object pressed on it) will be distributed. Spread evenly across the surface of the drain, helping it withstand greater impact forces. As for the design of other geometric forms, the manhole cover will be fragile when the surrounding corners are weaker than the rest.

Economically, the design of circular manhole covers will save more materials . In addition, it has many advantages such as ease of transportation, installation, high safety because it is difficult to happen to overturn or fall into the manhole.