Second Avenue Subway Project, New York: Refurbishment of an Existing Underground Station

This paper will detail the major structural refurbishment required to an existing station to accommodate the new Second Avenue Subway. The existing mined and open cut structure was completed in the 1980s and today only half of the tracks and ancillary spaces are in use. As part of the Second Avenue Subway project, these unused spaces, platforms and tunnels will be reconstructed to enable trains to connect into the existing subway network. The major reframing of the deep station box will be described, including the complex sequencing and temporary supports required. The renovation of existing entrances and the construction of new street level entrances and ancillary structures integrated into residential and commercial buildings will be included. The challenges posed by the renewal of an underground space with restricted clearances and limited geotechnical and structural parameters will be highlighted.