The design of the structure of 175 Greenwich Street, as expressed by the mainframe of the east and west elevations, gives a clearly defined and legible form to the building. The external supporting structure is a load-sharing diagonal element on a 16-storey module that also emphasises the verticality of the tower. This divides into a finer grain at the corner elements.
All four corners of the tower are expressed in the same way with the use of symmetrical hangers with diagonal and vertical elements. The hung corners, divided into four-storey segments, liberate the floorplate edges creating column-free corners within the office spaces of the tower.
Two set-backs are created to achieve variation on the floorplate size higher up in the building. The height of the ‘shoulder’ at the southern corner has been defined in relationship to its proximity to Tower 4 at 150 Greenwich Street – and as a response to the way in which it is cut back – thereby making an architectural gesture towards the Freedom Tower diagonally opposite. This achieves a greater separation between the different towers as well as enhanced views for occupiers at higher levels.
At ground level, the use of a triple height cable-net façade to the West, onto Greenwich Street, reinforces the transparency of the entrance to the lobby and the combined retail and transit hall facing the Memorial Park.
In the transit hall, the corner of Greenwich and Cortlandt Streets is animated by the use of exposed glazed lifts and glass floor landings where they meet the escalators. The transit hall forms part of the access to the transport hub and connects Towers 2, 3 and 4 at the below grade levels through a retail concourse (designed by Santiago Calatrava).