of mining the combined talents of contractors who are being asked to perform the work,” says Scott Ehrhardt, PE, a senior associate with Dewberry. “The Martinsville project is a perfect example of how we can effectively access the collective talents and creativity of contrac- tors who are accustomed to bidding rehabilitation projects, thereby ensuring we are delivering the best solutions for our clients.” An Affordable Rehabilitation The city was able to complete the ambitious amount of repairs in 2.5 years. Challenges included historical rainfall events, significant infiltration, heavy sediment and debris deposits within the existing in- terceptor, bypass system malfunctions, unmarked utilities, vandalism, fire and freezing of the bypass system, and unstable slopes and river embankments. Despite these obstacles, the construction was completed for less than $17 million, and as a result of the overall cost savings, the city’s Water Resources Department has been able to address additional targeted deficiencies within the system, including further CCTV in- spections, flood damage repairs, and critical sewer repairs utilizing CIPP. The project serves as an example of a successful and affordable reha- bilitation of a large-diameter sewer line for a rural community working with a limited budget. “Major deficiencies in the Smith River Intercep- tor posted significant risk to both the public and the environment,” says Mike Kahle, director of water resources for the City of Martinsville. “Dewberry’s approach and expertise was critical to the success we experienced in the rehabilitation of this major interceptor.”
Cured-in-place pipe (CIPP) was used as a key sewer rehabilitation method.
The bypass piping operated the system 24/7.
contractors to employ their strengths and competitively bid the work. The phases consisted of: • Contract I: Emergency replacement of 750 linear feet of collapsed cor- rugated metal pipe with highly complex site conditions, including the steep slope along the Smith River • Contract II: Installation of 5,200 linear feet of parallel gravity sewer • Contract III: Alternative selection of sewer rehabilitation methods, including replacing in place, cured-in-place pipe liner (CIPP), or parallel sewer installa- tion.Where possible, multiple rehabilitation methods were identified fromwhich contractors could select based on their respective strengths and capabilities. • Contract IV: Repair the collapsed sewer and CIPP lining on an industrial site The first three contracts were funded through the Virginia DEQ’s Revolving Loan Fund while the fourth contract was primarily funded by the EDA grant. “If we expect to achieve cost-effective, creative solutions in our designs, we as design engineers must do a better job
Post-construction, the retaining wall will remain in place, mitigating the slope along the Smith River.
LESLIE BARKSDALE, PE, is a project manager in the Danville, Virginia, office of Dewberry.
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csengineermag.com
may 2020
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