By summer, Arup is expected to present a design plan that addresses the unexpected amount of bouncing experienced by pedestrians crossing an HNTB-designed bridge in Brooklyn.
On Jan. 21, the Brooklyn Bridge Park Corp. filed a lawsuit against HNTB in the Supreme Court of the State of New York, stating, “Subsequent review has shown that the design for the bridge was inherently flawed.”
The $3.9-million, 450-ft-long Squibb Park Bridge, which zigzags between Brooklyn Heights and Brooklyn Bridge Park, opened in March 2013 and was designed to bounce mildly. The website for the bridge states: “Walk across the award-winning Squibb Park Bridge and you may notice a little spring in your step. That’s because it was designed to be lightweight and flexible like the trail bridges in our state and national parks.”
But residents began complaining that, over time, the bounciness grew. The bridge was closed in late 2014.
The underslung suspension pedestrian bridge marries environmentally friendly black-locust timber with draped steel-cable supports. After 16 months of working with HNTB to identify the flaw’s cause and collaborate on a solution for the bridge, Brooklyn Bridge Park officials filed the lawsuit, seeking at least $3 million in compensation.
Ted Zoli, HNTB’s national chief bridge engineer, declined to comment, as did HNTB.
Arup was on the design team responsible for the steel suspension Millennium Bridge in London that was shut down after dramatic swaying alarmed users on its opening day, in June 2000 (ENR 7/10/14 p. 14). It took some 100 tonnes of dampers and several million dollars of work to steady the bridge.