New York City’s historic landmarks are an integral part of the city’s vibrant culture and landscape. The City of New York established the Landmarks Preservation Commission in 1965, in response to the demolition of a number of historically relevant properties, particularly the original Pennsylvania Station that was built in 1911. According to the LPC, a landmark is defined as “a building, property or object that has a special character or special historical or aesthetic interest or value as part of the development, heritage, or cultural characteristics of the city, state, or nation.”
Since then more than 36,000 properties in New York City have been designated as landmarks. Once a building has been designated as a landmark, the LPC is required to approve any alteration, reconstruction, demolition or new construction. This is required for individual landmark buildings as well as buildings within a designated historic district.
Although part of the landmark preservation regulations includes maintaining a building’s architectural style and character, there are more than aesthetics involved. Historic structures can be more susceptible to damage from construction activities than newer more modern buildings. Vibration levels from construction activities in areas adjacent to historic buildings can also impact these buildings and their foundations. Historic buildings can be significantly affected by demolition and foundation work being conducted in the vicinity.
New York City building code requires surveying and monitoring of construction work within a 90-foot radius of any designated landmark. Technical policy TP 10/88 details the types of surveying and monitoring that must be in place at these building sites. A complete monitoring program in a landmark building or adjacent area includes a combination of services such as pre-construction surveys (existing conditions photographic documentation), Optical Structure Survey, remote or manned seismographic vibration monitoring equipment, crack gauge monitoring, and tilt meter monitoring.
Pre-construction surveys and ongoing vibration monitoring are crucial for detecting any potential issues prior to the start of a construction project or during the project. Monitoring and surveying are part of a comprehensive approach that can serve to protect not only the historical structures and residents of the area, but other stakeholders involved, including developers, building owners, contractors and site engineers.
Detailed information and latest updates on the NYC LPC can be found at: https://www1.nyc.gov/site/lpc/index.page