We had inspected the manhole cover with Facilities team and found that the structure was mistakenly built/repaired from the design. The manhole cover was not lied onto the side of manhole but welded connecting to it. When the load was there, the manhole cover was just suddenly collapsed.
Primarily, we will check the record of the manhole repair and do survey each manhole with Facilities team of their safe structure. If possible, do you know when this hole was repaired and by whom?