Everyone sees the hole in the beam web, right? I mean, the rust ate straight through the web, creating that big irregular hole on the right. It would be rude to not acknowledge all that hard work on the part of oxidation. The brick covering the beam has been removed and there’s the hole for all to see.
There are more interesting things going on here. For instance, the six square nuts represent the back side of a beam to girder connection, with a roof beam running off away from us, inside the building. These are low-strength bolts – referred to in the distance past when I took steel design in school as “unfinished bolts” – and the relatively cheap steel is not faring well. The pattern of damage on the nuts and protruding bolt ends – with cylindrical delamination of rust surrounding each bolt is sometimes referred to as a “rosebud” rust pattern. As long as the shaft of the bolt bearing on the visible beam web is intact, the connection still works, but it’s loosened up a lot from when it was built.
Both the top and bottom flanges are rusted, which is no surprise given the condition of the web. That rust is a lot harder to see, because it’s trapped between the body of the beam and the masonry above and below, but is arguably more dangerous in the long run. A hole in the web won’t cause the beam to fail unless it’s quite big, but losing material off the flanges greatly reduces the beam’s carrying capacity.
My favorite issue here is not related to weathering. There’s an empty bolt hole just to the left of the middle bolt in the right-hand column of three. Given its location, it never had a bolt in it. Rather, that hole is a mistake on the part of the steel fabricator, some 110 years ago. My guess – and this is purely a guess – is that it was meant to be the first hole of the six needed for the beam connection, and the fellow drilling or punching the holes decided to double-check his dimension after he made the first hole rather than before. Fortunately, the presence of that hole does not significantly weaken the connection.
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