A new modern bridge replaced the Grace Memorial Bridge (1929) and the Silas Pearman Bridge (1966) carrying Interstate 17 across the Cooper River from Mount Pleasant to the Charleston peninsula. Crossing an important waterway used by the majority of the ships calling at Port of Charleston, the risk of ship impact had to be considered in the design of the bridge.

Ship accident and incident records were collected and used for statistical determination of the probability of aberrancy. Evaluation of the performance of the artificial islands protecting the main piers was based on extensive numerical simulations. Critical impact scenarios were identified and scale model testing was used to further document satisfactory performance of the islands.

Extensive documentation was produced to provide the SCDOT with an in-depth basis for the ship collision design requirements and critical assumptions regarding future conditions was highlighted with guidelines on regular reevaluation to ensure that the safety of the bridge remained acceptable.