City of New Martinsville
New Martinsville, West Virginia
Burgess & Niple (B&N) provided preliminary engineering, license application, and general plans and specs for construction of a 34-megawatt (MW) hydroelectric plant at Hannibal Locks and Dam on the Ohio River.
B&N provided a preliminary cellular cofferdam design and layout to permit construction of the powerhouse. B&N’s geotechnical investigation included 15 test borings to determine subsurface conditions in the vicinity of the proposed cofferdam cells. Test borings reached a maximum of 100 feet and included up to 50 feet of rock core samples for direct shear and triaxial testing to determine rock strength.
The height of the cofferdam cells was approximately 60 feet, designed to retain approximately 35 feet of water overlying 20 feet of saturated sand and gravel. Test borings disclosed that a weak layer of clay shale existed beneath the sand and gravel at the base of the cofferdams and had to be accounted for in the sliding stability analysis. This required the use of concrete thrust blocks - tied down with rock anchors - to increase resistance of the cofferdams.
B&N also provided oversight and construction services.