The bridge superstructure is designed to withstand shipping accidents and the natural disasters that have plagued Charleston 's history . The span is designed to endure wind gusts in excess of 300 mph ( 480 km/h ) , far stronger than those of the worst storm in Charleston 's history , Hurricane Hugo in 1989 . Engineers also considered the 1886 earthquake that nearly leveled Charleston . The Ravenel Bridge is designed to withstand an earthquake of approximately 7.4 on the Richter magnitude scale without total failure . To protect the bridge from errant ships , the towers are flanked by one-acre rock islands . Ships will run aground on the islands before colliding with the towers
1886 earthquake
1886 Charleston earthquake
Arthur Ravenel Jr. Bridge