Erecting new buildings in New York City’s old neighbourhoods

Abstract

The New York City (NYC) construction boom of 2004–2008 was accompanied by a series of accidents occurring, in particular, during lot-line demolition and excavation operations. The forensic investigations performed by the NYC Department of Buildings revealed that most of the accidents had occurred when the buildings adjoining the site were of pre-1900 vintage. The destabilising effect of demolition or underpinning on these empirically designed masonry buildings had not been properly assessed. The paper presents statistics derived from the department’s incident database and describes specific cases that had occurred during demolition, during underpinning or in relation to party walls. The lack of engineering involvement in the design of these activities was deemed the most important cause. The findings of the forensic investigations provided the technical arguments for new provisions that were introduced in the 2008 and 2014 editions of the New York City Building Code.