Overlooked Design: The Manhole Cover - Design Bureau

Overlooked Design: The Manhole Cover

Friday, August 12th, 2011

Most manhole covers are made from cast iron, measures between 22 and 60 inches in diameter, weigh anywhere from 200 to 300 pounds, and yet, they often go unnoticed. When major cities began installing sewer systems in the late 1800s, sanitation officials commissioned artisans to design diverse manhole cover patterns, which often included floral motifs and cityscape sketches. These covers, though pretty, became true traffic obstacles when wet because their surfaces would become extremely slick. Designers quickly introduced the high-traction grid and basket-weave patterns, sacrificing design style for practical functionality. These basic patterns became even more commonplace in the early 1900s as automated machining replaced handcraft manhole production.

Today, the ubiquitous grid pattern typically jazzes up the manhole’s street surface, while a spiderweb pattern spans its underside to enhance structural support. Most US cities stick to these standard patterns, but many international cities, including Tokyo and Vancouver, are known for more fanciful manhole patterns. So the next time you’re walking down a street, be sure to look down. You might be surprised by the manhole designs plugging up the street.

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