Replacing a Gem

Since its 1913 construction, the Lime Kiln Bridge in Vermont has been considered an architectural and scenic gem. However, by 1996, it was clear that the narrow and deteriorated bridge needed to be replaced. This article describes the permitting, design and construction challenges of replacing the bridge with something that matched the architectural beauty of the original bridge. The project had to obtain numerous state and federal permits, often with conflicting requirements. The Vermont Transportation Agency (VTrans) also spent a year negotiating with the state's Department of Historical Preservation regarding whether the old span could be rehabilitated. As a compromise, VTrans agreed not to remove the old span until it had been fully documented by architectural historians. The bridge presented several logistical challenges due to the bridge's location between two rock quarries and the need to complete construction on a tight schedule while maintaining constant vehicular, railroad and pedestrian access. Prestressed concrete slabs were used to create a bridge design that simulated the original bridge's decorative geometrical features while adding modern ornamental and safety features. The bridge's surface was outfitted with deicing membranes to prevent the deterioration that had damaged the original bridge. The new bridge has already received several awards and honors in the engineering industry.