Location: Parkton, MD
Owner: City of Baltimore, Department of Public Works
General Contractor: Brayman Construction Corp.
Value: $6 Million
Date Complete: April 2010
The Prettyboy Dam project involved the installation of an underwater anchorage system necessary to secure the concrete gatehouse to the dam. Work required underwater drilling, installation, and stressing of 38 bar anchors and 12 mid-width holes through the face of the dam in depths up to 110-feet. The bar anchors ranged in length from 50-feet to 70-feet. The 5.5" diameter drill holes were core drilled, water tested and redrilled before installation of the anchors. As part of the bar anchor work, Brayman also installed 6 precast concrete cross-beams and steel brackets (wales for anchors). All underwater work was supported utilizing a certified diving subcontractor working from a barge platform. Other miscellaneous work included spall repairs, crack repairs and epoxy injection along the interior walls of the existing gatehouse.
Dam rehabilitation experts believe this project to be the first of its type in the world with respect to the underwater processes, the depth of dive, and the installation of the 70' post-tensioned anchors. The dam creates the Prettyboy Reservoir, which has a design storage volume of about 19 billion gallons. Together with the downstream Loch Raven Reservoir, the reservoir provides about 60% of the water supply for the 2.7 million residents of the Baltimore metropolitan area. Control of water flow through the dam is via a concrete gatehouse which is monolithic with the dam.
ASDSO National Rehabilitation Project of the Year
ACEC/MD Engineering Excellence Outstanding Project
ASCE Outstanding Small Project
ASCE Outstanding Engineering Achievement of the Year