Committee approves protective concrete slab contract to shield Broad River Road water mains

A Richland County committee voted to award a contract to Shady Grove Construction LLC to install a reinforced concrete protective slab over sections of Broad River Road where large-diameter water mains run beneath the planned widening. The base contract amount is $347,203; with a 15% contingency the total approved amount is $399,283.45. The vote was recorded by roll call as unanimous (Pugh, Livingston, Weaver, Aline, Mackey/Maki voting yes).

Staff (Speaker 4) described the slab as 12 inches thick, roughly 20 feet wide and more than 300 feet long. The slab is intended to protect an existing 54-inch and portions of a 36-inch water main so the mains would remain in place rather than be relocated. Staff said the South Carolina Department of Transportation reviewed and approved the plan on the condition that protective measures were provided, and that Columbia Water had engineering input on risks and workmanship.

Committee members raised questions about future maintenance and whether the slab would prevent access for repairs. Staff responded that the protective cap will make penetration more difficult but that the mains are large and that most repair scenarios that would require cutting the slab would be indicative of catastrophic failures; staff said the design includes provision for air releases and other features to maintain serviceability. Staff also described material testing (ultrasound on pipe thickness and soil testing) and said moving the mains would dramatically increase cost and risk of service interruption, so the protective cap was the preferred and DOT-accepted approach.

The committee approved the award by roll call. Staff will proceed with contract execution and construction coordination with DOT and Columbia Water as part of project implementation.