Fixing NYC’s aging infrastructure one engineering problem at a time

brightly colored safety vests and harnesses — have clambered up Manhattan Bridge cables to install sensors that measure the effects of vehicles crossing the span. They also have climbed onto the Verrazano Narrows Bridge to measure the impact of thousands of footfalls of New York City Marathon runners.

His sensors also monitored vibrations during renovation projects at the Metropolitan Museum and the New-York Historical Society. During renovation of the Met’s Costume Institute, museum officials wanted to ensure the safety of fragile objects in the adjacent Egyptian Wing.

Culligan, who co-directs the Earth Institute’s Urban Design Lab, is also a director of an interdisciplinary program with the architecture school that focuses on designs for future cities. She has a Ph.D. from Cambridge University in England and taught at MIT before coming to Columbia in 2003.

She is working on a project involving green roofs, planted vegetation on rooftops to absorb storm water that would otherwise gush into the city’s sewer system. In New York, she explains, storm water and sewage typically flow into a single pipe, and anything wastewater treatment facilities can’t handle goes directly into local waterways, including the Hudson River, and then into the ocean. There are hundreds of green roofs around the city, including seven on the Columbia campus, she points out, and the city is working to create incentives for private homeowners to install more.

“The goal is to work with the community to solve problems,” Culligan says.

These plantings typically take up about half of a rooftop and consist of several layers of engineered material, including a growing medium for plants, on top of a normal roof. Similarly, extended tree pits and landscape elements inserted into sidewalks are designed to soak up rainwater and divert overflow from the street to these green spaces. Sensors measure how much water these systems soak up.

Culligan also works with the community group Bronx River Alliance to monitor water quality standards. Because litter, often thrown into sidewalk green spaces, clogs city drains and adds to water quality problems, she is collaborating with Ester Fuchs, a professor at the School of International and Public Affairs, to understand the location of litter “hot-spots” around the city, with the aim of stopping trash where it starts.

“New York is a city of eight million with a diversity of conditions and people, so there are a lot of opportunities for a living laboratory,” Culligan says. “Columbia is lucky to be in this great, global city.”