Someone’s been doing a lot of exploratory work on the rear and side facades of 120 Broadway (we’re looking at the Nassau Street/Cedar Street corner here). This building, the second Equitable Life Assurance headquarters on that site, was completed in 1915 (the previous building had burned in 1912) and has a steel frame supporting masonry curtain walls. The walls are mostly brick veneer at the typical floors, with terra cotta veneer at the bottom and top; the back-up masonry is all common brick.
It’s always hard to tell what someone else is thinking but it looks like they’re cutting probes to determine a cause for damage. There are a number of possibilities abilities on a building of this age: terra cotta material failure, mismatch in movement between the veneer and brick, rusting steel columns, failure of the ties between the terra cotta and the brick, failure of ties between the masonry and the steel, and so on. Examining a building like this is a not a search for a new and unique cause of damage, it’s a search for evidence to link the known problems to one of the known possible causes.