Base Charleston, the U.S. Coast Guard base located in North Charleston, South Carolina, needed to be upgraded to accommodate five cutters to increase our national security. Part of the modernization project included demolishing Pier November, an old 1,100-foot concrete pier, and removing nearly 800 concrete piles underneath it.
In its place, a new 1,100-foot Pier November, supported by 460 24-inch-by-74-foot-long square concrete piles equipped with 40-foot steel stingers, would be built. The new pier is a 28-inch-thick, two-way cast-in-place concrete slab. The project also called for strengthening the waterfront infrastructure.
To accommodate the more robust power requirements of the new pier and the five national security cutters it will serve, eight precast concrete vaults were designated to house the necessary electrical equipment—power cables, transformers, and communication lines.
Whiting-Turner’s South Carolina federal branch was the general contractor, Russell Marine, headquartered in Channelview, Tex., built the pier and installed the precast vaults, and Knight’s Precast, headquartered in Summerville, S. C., fabricated the precast vaults.
Precast Was Prescribed
The engineers’ plans called for precast concrete vaults from the get-go. Precast concrete is known for its excellent durability in marine environments. Building with precast elements also speeds project completion. And since the precast elements are created in a quality-controlled factory environment, the tolerances are more accurate.
The unusual installation location of these vaults was also a consideration. They were to be attached to the underside of the pier.
“Accuracy and ease of installation, relative to attempting to cast them in place, was the driving factor in the selection of precast,” said Ryan Breslin, assistant project manager for Russell Marine’s North Charleston, S.C. branch. “If we built them in place, depending on the tide, part of the job would have had to be underwater, so it would have been more challenging.”