Project DetailsLocation: Christiansburg, Virginia
Owner: Virginia Department of Transportation
Contractor: DLB Enterprises, LLC; Tricor Construction, Inc.
Precaster: KJ Williams Concrete Company
Engineer: Gay and Neel, Inc.
The Huckleberry Trail near Virginia Tech carries commuters and recreational users between Blacksburg and Christiansburg, Virginia. In recent years the trail has undergone expansion to increase the length and add to the area’s network of trails. Coinciding with roadway improvements in Christiansburg, a new bridge was required to cross Peppers Ferry Road to extend the trail deeper into the town.
Engineered by Gay and Neel, Inc., and dedicated in 2015, the arch bridge is named after Renva Weeks Knowles, a longtime resident of Christiansburg, who donated over $1 million to be used for improvements to the trail. A plaque is fixed to the ornamental bridge abutment design.
The approach ramp to the bridge deck on the north side is a back-to-back mechanically stabilized earth (MSE) retaining wall, sloping from grade to a height of roughly 20 feet. The width of the ramp varies between about 16 feet and 30 feet. In a back-to-back wall MSE design, the soil reinforcements extend from both wall faces and overlap a distance of at least 30 percent of the height of the wall.
In a back-to-back MSE wall design, the soil reinforcements extend from both wall faces and overlap a distance of at least 30 percent of the height of the wall.
The overlap of soil reinforcements reduces the amount of lateral earth pressure within the volume of fill, further economizing the design of the internal stability of the MSE walls and allowing for a reduction in material and construction time.
Precast coping was anchored to the top course of the MSE wall panels, providing stability to the pedestrian railing running along the top of the wall.
Overall, the MSE wall provided an ideal solution for the bridge’s north abutment, based on factors such as foundation type, cost, and aesthetics to match the architectural appeal of the new bridge.