STRUCTURAL ROADWAY SPANS THE GAP

摘要

The Jefferson County Department of Highways and Transportation recently constructed a 670 m (2,200-foot) long extension of Coal Mine Avenue in Jefferson County, Colorado. The roadway extension crosses over the Economy Mine, an abandoned coal mine located between 38 and 52 m (125 and 170 feet) below the ground surface. Existing sinkholes in the immediate vicinity of the Mine and above nearby mines in similar geologic conditions created substantial concern for the safety of motorists on the roadway. To reduce the risk, a structural concrete slab was designed and constructed to bridge potential sinkholes. This paper reviews geologic and mine conditions, and presents mitigation alternatives evaluated and design of the slab.