The rehabilitation and upgrade of the Sheppard-Myers Dam in Hanover, Pennsylvania, was completed in May 2023. PENETRON ADMIX SB, a crystalline concrete waterproofing admixture, was specified to maximize the durability of the dam’s new concrete structures.
Located in south-central Pennsylvania in Hanover, 54 miles northwest of Baltimore, Maryland, and 5 miles north of the Mason-Dixon line, the Sheppard-Myers Dam was originally constructed in 1932. This dam impounds water for use in Hanover, Pennsylvania, a town of just over 16,000 inhabitants, and the immediate region. With a capacity of 217,400,000 gallons, the dam’s reservoir covers an area of 46.5 acres; the surrounding watershed area was reforested with a total of 1,500,000 trees.
“The Dam is responsible for about 20% of the local water supply and has not had a significant upgrade since the 1930s,” adds Christopher Chen, Director of The Penetron Group. “Without an upgrade, the Pennsylvania Department of Environmental Protection would have required the complete decommissioning of the facility.”
The $10.84 million rehabilitation of the Sheppard-Myers Dam comprised the construction of the new, larger concrete labyrinth spillway with added capacity to accommodate current government standards for a maximum flood event, and rehabilitation of the downstream face of the dam, including the installation of a subsurface drainage system.
“After the design phase of the project by Gannett Fleming, the project engineers, Penetron was asked to provide a permanent waterproofing solution for the new concrete structures,” says Christopher Chen. “Thanks to our proven success with similar projects across the Mid-Atlantic region and competitive costs, PENETRON ADMIX SB was specified as the concrete waterproofing solution for the Sheppard-Myers Dam upgrade.”
Hanover Concrete, the project’s concrete ready-mix supplier, provided PENETRON ADMIX SB-treated concrete for the new auxiliary spillway and weir walls.
Once added to concrete, the proprietary chemicals in PENETRON ADMIX SB react in a catalytic reaction to generate a non-soluble crystalline formation throughout the pores and capillary tracts of the concrete. These crystals permanently self-heal and seal micro-cracks, pores, and capillaries against the penetration of water (or liquids) from any direction – making the concrete impermeable.
“The dam’s new concrete structures are now impermeable to water, even under the constant hydrostatic pressure typical of a water storage facility like the Sheppard-Myers Dam,” adds Christopher Chen. “The ability of PENETRON ADMIX SB to permanently self-heal any future microcracks will also mitigate concrete deterioration over the service life of the concrete.”