Alteration Scars

by Don Friedman on May 13, 2016

You can learn a fair amount about steel construction just looking around in the New York subways. A lot of the steel is exposed (unlike in buildings, where it’s hidden behind fireproofing and finishes) and you can walk right up to it and stare at it while waiting for your train to come (unlike at most bridges, where you’re speeding by).

Mona took a couple of pictures that give you the idea:

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In both, we’re looking big built-up girders, with plate webs and double-angle flanges. The plate that is the center of each photo is a web-plate splice. The things in front of those splice plates are remnants of double-angle beam connections for beams that used to come out-of-plane towards us. In the second picture, a stub of the burned-off beam web is stuck between the connection angles, hanging on by being partially fused to the burned-off legs of the connection angles that used to come out-of-plane towards us. In the first picture, there’s no remnant of the beam, so there’s a small gap visible between the angles remnants.

If we drew a plan of the steel, we could try to figure out what used to be here and why it was removed. There have been a lot changes over the years – stairs added, stairs removed, ventilators added, elevators added, platforms extended, and so on – so there are a lot of potential reasons for beam removal.

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