Upper Manhattan’s Park Avenue Viaduct is a critical component of Metro-North Railroad’s track infrastructure, used by approximately 750 trains daily between Grand Central Terminal and Metro-North’s three rail lines east of the Hudson River. However, this four-track, 6,450-foot-long, elevated steel-framed structure has age-related deterioration. Therefore, Metro-North commissioned a study to support major segment repairs or replacement.

EnTech performed structural inspection of the aboveground structure, and environmental and geotechnical engineering services for subsurface investigations. The structural study, encompassing two viaduct segments that totaled 12 city blocks, entailed a visual conditions inspection of steel columns, girders, floor beams, stringers, secondary members, and deck.

EnTech’s environmental and geotechnical engineers performed soil and groundwater investigations to characterize subsurface conditions beneath the viaduct. The team collected 52 soil sample sets, as well as groundwater samples from temporary well points. Environmental samples were analyzed for volatile and semi-volatile organic compounds.