I wrote about the Columbus Monument once before, but that post was so brief as to barely exist. The picture of the monument above, from 1903 or so, inspired me to discuss the most structural-engineering aspect of the monument: it sits on top of a train station that wasn’t there when it was built.
Let’s start with some non-construction history. Columbus had a great reputation, in broad terms, when the monument was built in 1892; his reputation today is quite a bit worse. He has no connection to New York unless you want to count the rather tenuous “kicked off European colonization of the Americas” as a connection. Realistically, we should have a statue of Giovanni da Verrazzano, who was the first European to enter New York Bay, about 90 years before Henry Hudson and some hundred years before the Dutch colonists showed up. On the other hand, Columbus has no connection to Ohio and they have a whole city named after him, so maybe we got off lucky. There has been discussion of removing the statue and replacing it with something else, but, unlike the similar discussion about the Roosevelt memorial at the American Museum of Natural History a mile to the north, it seems to have died down.
The monument is unreinforced masonry and, as is obvious in the picture, very slender. In other words, it’s fragile. It was quite exposed to traffic for much if its history, as the big circle that it’s in the center of was a free-for-all; traffic islands directing cars to specific paths in the mid-1900s helped, and then the circle was given a big circular island/mini-park in 2005. The intersection is a traffic mess, with heavy traffic from Central Park West to the north, Eighth Avenue to the south, very wide and two-way Broadway to the northwest, narrower and one-way Broadway to the southeast, and 59th Street to the east. Until the 1950s, 59th Street continued to the west before it was eliminated to create a double-wide block. Urban traffic circles like this, whether with parks in their center or not, are a planner’s way of resolving complicated traffic patterns.
Because of the non-alignment of the downtown and uptown portions of Broadway, the construction of the IRT subway circa 1902-1904 did not go directly below the monument. Rather, it skirted the monument to the west. The cut-and-cover excavation still required shoring the monument and protecting its foundations, but that was far less onerous than the underpinning that the IRT company had to perform on building after building. The construction of the IND subway under Central Park West and Eight Avenue in the 1920s was a different story. That tunnel and station were wider than the IRTs and went directly under the monument, as well as the IRT station. The monument was shored but ended up with a tilt, which led to repairs that, as far as I know, did not entirely straighten it out.
It could have been worse. General Worth is buried under his monument on 25th Street, and when the BMT subway was built, it went more or less underneath him.