AECOM Technology Corporation of Roanoke and Whitman, Requardt & Associates of Blacksburg have earned Honor Awards in ACEC Virginia’s Engineering Excellence Awards Competition. AECOM was awarded for engineering design services provided to Alleghany County’s regional sewerage system and for finding grants to fund this project. WRA received an award for its work on Roanoke’s Tinker Creek Bridge and Connector Trail.

Here is the press release from AECOM.

AECOM Technology Corporation of Roanoke has received an Honor Award, the second highest award, in ACEC Virginia’s Engineering Excellence Awards Competition.

AECOM provided engineering design services for Alleghany County’s entire regional sewerage system and assisted the County in obtaining grants and low interest loans from five different agencies to help support the project.

In addition to AECOM, Whitman, Requardt & Associates (WRA) of Blacksburg, engineers for Roanoke’s Tinker Creek Bridge and Connector Trail, also received an Honor Award

Alleghany County’s Regional Sewerage System: The new system is producing effluent significantly under permitted limits, with no sewer overflows and at lower operating costs than projected. This project successfully provides critical infrastructure to 40 percent of this rural, economically depressed county, while protecting natural resources in a cost effective manner.

AECOM developed a preliminary engineering report, prepared construction documents and provided bidding and construction phase services for a new, multi-jurisdictional, regional wastewater treatment plant; a new, 300-foot, two-lane bridge to provide access to the new wastewater treatment plant; five miles of new, 8-inch to 20-inch force main wastewater conveyance system; four pump stations; and conversion of the existing Clifton Forge wastewater treatment plant to a pump station.

AECOM assisted the County in successfully securing grant funding totaling $17,530,400 which was applied to the final total project cost of $25,630,186, with the remaining costs financed using low interest loans. Additionally, VDOT funded $2M toward a new, two-lane, 300-foot long bridge over the Jackson River to serve the new treatment plant.

Alleghany County was under a Consent Order from the Virginia Department of Environmental Quality to eliminate sewer overflows at their pump stations. While satisfying the Consent Order, the County also wanted to increase the region’s wastewater treatment service area and capacity to promote economic development.

Tinker Creek Bridge and Connector Trail: The 1.2 mile Tinker Creek Bridge and Connector Trail is a multi-use trail connecting two existing trails: the Roanoke River Greenway and the Tinker Creek Greenway. WRA provided an innovative and attractive bridge design to deal with numerous topological challenges including a 117-foot vertical drop to a riverside bluff using serpentine, terraced retaining walls and a trail alignment threaded between an earthen lagoon dam and the Roanoke River. Next, the trail soars above the Roanoke River with a 660-foot Z shaped, multiple span steel truss bridge, then dives down to tuck underneath the existing Norfolk Southern Railroad bridge crossing Tinker Creek.

A study performed by others aligned the trail through the wastewater treatment plant, generally following the bank of the Roanoke River through a heavily industrialized portion of the plant, and then proposed a single span bridge over three hundred feet long across that same river. After reviewing this alignment with various stakeholders, the study alignment was deemed too expensive for available construction funding. WRA’s revised alignment used the existing street network to route the trail around the wastewater plant and head toward the river through a wooded area on the plant property away from the industrial portion.
The trail then dives down toward a riverbank bench, requiring a 117 foot vertical drop at a maximum 9% grade within a tight footprint dictated by the available property limits. Next, the trail travels along the river toward a crossing, which was selected because of a dry rock outcropping, which reduced the bridge spans in half and provided for a more constructible economical bridge. The 660’ long multi span bridge structure follows a “Z” shape and soars over 25 feet above the river to position the main spans above the 100 year flood. Finally, the trail double backs on itself on the opposite bank to dive beneath the Norfolk Southern Railway bridge and connect with the Tinker Creek Greenway. All of these trail elements required close coordination with the City, the Wastewater Treatment Plant, Norfolk Southern Railway, VDOT, and the regional trail planning commissions.