The Design/Build Process The signature design for this single cable-stay bridge has evolved from public input, engineering requirements, and the expertise of the world’s leading bridge and lighting designers. The bridge footprint was determined to create minimal impacts to existing neighborhoods within the city of Charleston and to be sensitive to the enhancement of the public realm. Through several public hearings, the local public chose the diamond tower design from other options. Letters, testimony, and even a local bumper sticker campaign worked to add a pedestrian/bicycle component into the bridge design. Local officials offered their insight to enhance interchange options with additional ramps to Morrison Drive in Charleston and Wingo Way in Mount Pleasant. Cables The key to a cable stay bridge is definitely the strength of its cables. The Cooper River Bridge's 1546 foot main span is suspended by 128 individual cables between the support piers. Cables are anchored on the deck level and inside of the diamond towers. Each cable can hold over one million pounds or 500 tons. A single cable is composed of many seven-wire strands twisted together. Some of the strongest cables on this bridge are formed by 90 seven-wire strands. To protect the cables from changing weather conditions they are enclosed in a high density poly-ethylene (HDPE) pipe. The white pipes used on our bridge will range in diameter from 12 to 20 inches. Towers In several public hearings held throughout the Charleston region, the local public chose the diamond tower design from other options. The cable stayed span hangs from two diamond towers at each end of the 1546 foot span. A signature icon for the Charleston region, these towers reach over 575 feet into the air and support a road deck almost 200 feet above the median high tide mark. Specialty features include platforms and tower elevators included for safety inspections and maintenance. Bike and Pedestrian Letters, testimony, and even a local bumper sticker campaign worked to add a pedestrian/bicycle component into the bridge design. The last design plans included a 12 foot bicycle and pedestrian lane 2.5 miles across constructed along the ocean-side of the new bridge from Morrison Drive to Coleman Boulevard. The bicycle/pedestrian lane travels along the outer edge of the bridge's tower piers and offers observation sites with benches to gaze out upon the beauty of the Charleston region. Rock Islands The Rock Islands have been designed to prevent out of control shipping vessels from running into one of the main span tower piers. The rock island works to stop a ship before it ever hits the tower by causing it to run aground. Each rock island is approximately one acre above the water and extends down to five acres across the bottom of the riverbed. They are constructed with three sizes of Newfoundland limestone. Fun facts Did you know... The drilled shafts supporting the main towers reach more than 230 below the waterline and into the earth; from waterline to the top of its trusses the Pearman Bridge is 285 feet high. Did you know... The bridge has been designed to withstand an earthquake as powerful as the one that occurred in 1886. Did you know... The clearance from the high mean watermark and the bottom of the deck span is 186 feet. Did you know... You could hang 110 Toyota Camrys from one of the single pieces of rebar, 2.25 inches in diameter, used in to construct the cages in this project. All information is provided by the SCDOT. www.cooperriverbridge.org