Oakland Underfoot

This large and elaborate East Bay MUD access cover, on San Leandro Avenue in deep East Oakland, displays a lovely radial design. It also includes good examples of some typical features of access covers.

At the top and bottom edges, at 12 and 6 o’clock, are lifting notches, where a worker attaches the hooks to raise the lid safely. Halfway out from the center is a ring of aeration holes, arranged on the major compass points. They happen to be filled with dirt, except for the one marking Northeast. Their function is to equalize the pressure between the hole and the atmosphere, guarding against the effects of unusual events, like a tornado in the air or a sudden flood or explosion down below, that might push the lid out of its rim.

The smaller lid on the right side has its own lifting hole. Presumably it allows access so someone can monitor conditions in the shaft without going through the chore of pulling off the large lid. Because a smooth finish could present a slipping hazard, the secondary lid was textured by a welder. Perhaps there’s an arcane pattern in it representing a message, but it’s more likely to be a random set of metal bits, a scribble arranged by eye and intuition.

This entry was posted on 5 May 2017 at 9:46 am and is filed under  Access covers. You can follow any responses to this entry through the RSS 2.0 feed. You can skip to the end and leave a response. Pinging is currently not allowed.