When the South Carolina Department of Transportation decided to replace two bridges leading to Folly Beach, officials notified the local utilities that their pipelines and conduits would not be allowed to be suspended from the new bridges as they had been on the previous bridges. The existing bridges, spanning Folly Creek and Folly River, held a wastewater force main, communication conduits and gas mains that would need to be replaced and relocated under the two waterways. Horizontal directional drilling (HDD) methodology was quickly viewed as the easiest and most feasible means of construction to accomplish this task. The City of Folly Beach chose BP Barber (now URS Corporation) to begin investigations and design an HDD crossing for the 8-inch wastewater force main. Soon thereafter, both AT&T and South Carolina Electric and Gas (SCE&G) inquired about performing a joint HDD project to install the three 4-inch conduits and a 6-inch steel gas main, respectively. URS had primary responsibility to the City of Folly Beach, but were involved in drafting agreements on design, inspection and cost sharing between the three entities. URS designed a bundled HDD with all five pipes being installed in a single pull – and this turned out to be the easy part. Negotiating the cost to share labor and equipment on a pro-rated basis, yet allow for material separately, was the true challenge. This paper will review the design and construction highlights of this challenging multi-pipe, multi-use HDD installation.
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