Well, i didn’t necessarily either, but the internet can serve up some great info, whether you are looking for it or not. I’m sure like most people, you don’t worry that your car’s wheel is going to break a manhole cover when you drive over it. I know I don’t. For drivers to have that kind of peace of mind, It goes without saying that manhole covers, sewer grates, and other access covers need to stand up to all kinds of abuse over a lifespan of up to 50 years.
This video from Saint-Gobain PAM, a French manufacturing company, shows the kind of long-term endurance testing that they put their products through. The video’s narration is in French, but even without Google Translate it is fairly easy to figure out what is going on. Utilizing a contraption evidently called “The Carrousel,” a weighted mechanical arm that rotates around a fixed point that has two heavy truck wheels and tires mounted on the end of it, the company’s engineers simulate real world use. Every hour, each cover is subjected to the equivalent of 600 truck axles, each bearing an eight ton load, driving over it at about 30 mph. That’s about 5,000 passes in an eight hour day.
So the next time you wake up in a cold sweat at 2am worrying about the durability of manhole covers, just play this video to put your mind at ease. You can thank me later.