Awarded as the best online publication by CIDC

Why are some manhole covers designed into two triangular halves?

Why are some manhole covers designed into two triangular halves?

Manhole covers are generally made up of two pieces of triangular plates to form a square cover. One may wonder why two rectangular halves are used for a rectangular cover. To understand this, one should note that a planar surface is usually in contact with three support points.


For a triangular plate, the centre of gravity (CG) normally lies within the zone bounded by three support points even when loaded, thus creating a stable support system for the manhole cover. For a rectangular plate, the CG of a loaded manhole cover may lie outside the three support points, causing it to rock. Hence, the potential problem of rocking produced by vehicular traffic by rectangular traffic could be eliminated by using two triangular halves.

Different types of manhole covers

This question is taken from book named – A Self Learning Manual – Mastering Different Fields of Civil Engineering Works (VC-Q-A-Method) by Vincent T. H. CHU.

Advertisements

Share this post

Kanwarjot Singh

Kanwarjot Singh is the founder of Civil Engineering Portal, a leading civil engineering website which has been awarded as the best online publication by CIDC. He did his BE civil from Thapar University, Patiala and has been working on this website with his team of Civil Engineers.

One comment on "Why are some manhole covers designed into two triangular halves?"

Frederics Turnip says:

yes because the load on a triangular manhole is more evenly spread because it is a better design

Leave a Reply

Your email address will not be published. Required fields are marked *