Planning the replacement of the Beards Creek bridge

US Route 20A crosses Beards Creek, a tributary of the Genesee River, in the hamlet of Cuylerville near the Town of Geneseo in western New York. In early March 1994 fresh water (>20 mgd) began entering the Retsof Salt Mine ca 1100 feet beneath the bridge. Despite efforts to stop the inflow, it continued until early 1996 when the mine became completely inundated. Since March 1994, the bridge crossing the creek has settled 15 ft and moved ca 5 ft upstream toward the smaller of two large-diameter sinkholes centered on the creek which had developed ca 400 and 1300 ft upstream of the bridge. Both prior to and during the inundation of the mine, the owner of the mine and several public agencies conducted an extensive array of surface measurements, hydraulic surveys, subsurface investigations and predictive impact studies. Upon development of the sinkholes and the initial settlements, the bridge was declared unsafe and taken out of service. Public need and potential archeological resources in the immediate environs of the bridge require that the bridge be replaced, at its present location, with little or no taking of additional right-of-way. The authors' firms have been engaged in designing the replacement bridge and the restoration of the approach roadways. Their work has included the review and interpretation of the data and findings of the numerous studies conducted at and near the bridge site. They have used these reviews and interpretations as a basis for the hydraulic and foundation design for the bridge replacement and roadway restoration. This paper presents a summary of their design approach and rationale. (C) 1999 Elsevier Science B.V. All rights reserved.