Not What It Seems

An overly zoomed-in view of the Main Building at Ellis Island, completed in 1897: My first reaction is that is a heroic arch, 8 half-bricks deep with limestone bearing and key stones. On second thought, not so much. This is a bearing wall building, with a lot of structural steel used for the interior floors and the roof.[1] There’s also a lot of steel in the exterior walls: the openings have loose lintels made of multiple I-beams through the thickness of the wall. There is a heavy steel lintel of that type right over this arch – you can see a small ghost of its presence in the wide brick joint to the right of the top of the keystone. It gets more involved[2]: there’s some minor steel lining the curve of the arch, and the lintel is supported by a steel post just short of that vertical expansion joint. The joint, of course, gives away the game: if the arch were truly a structural arch, its thrust would be closing that soft joint. In any case, the vast bulk of the roof load is…