Wind study for City Island cable-stayed bridge over Eastchester Bay in the Bronx,New York City

Abstract

The existing seven-span bridge connecting the Bronx and City Island was opened to traffic in 1901. The existing bridge is planned for replacement by a new single-span asymmetrical cable-stayed bridge with a span length of 185 meters and a width of 20.85 meters. The steel tower (pylon) will be 50 meters high above the composite concrete deck and will be placed in Pelham Bay Park in the Bronx. The minimum vertical clearance above the water will be 4.50 meters. A wind study was initiated to determine: 1) the response of the bridge to vortex induced motions; 2) critical flutter wind speeds; and 3) buffeting responses of the bridge to design wind speeds, in its final configuration. The study also aimed to determine mitigating measures, if needed, to make the performance of the bridge acceptable. This paper presents the details and results of the study.