Look for the following Delve Underground presentations on the 2024 No Dig Show Session Schedule:

Trenchless Replacement of Aging Sewer Trunk Main in Sonoma, California
MA-T2-03, Monday, April 15 at 4:30 pm
The Sonoma Valley County Sanitation District’s Sewer Trunk Main Replacement Project includes 1.6 miles of 24-inch-diameter polyvinyl-chloride gravity sanitary sewer pipeline to replace an existing 18-inch-diameter reinforced concrete gravity sanitary sewer trunk main constructed in the late 1950s in Sonoma, California. The replacement pipeline is designed for open-cut installation and three trenchless crossings: (1) Happy Lane Cul-De-Sac, (2) Happy Lane to Orchard Avenue, and (3) Pequeño Creek. These crossings range from 120 to 200 feet long. The first two crossings are located within alluvium with potential for hard and abrasive cobbles and boulders. The third crossing is located within Sonoma Volcanics having a seismic velocity of up to 8,000 fps. The Happy Lane Cul-De-Sac crossing was recently constructed using steerable pipe jacking of a 42-inch-diameter steel casing. Challenges during its construction included bypass pumping, the proximity of a house, being located beneath the footprint of a swimming pool, and passing through tree roots and a portion of the existing trunk main and its embedment materials. Similar construction challenges exist for the Happy Lane to Orchard Avenue and the Pequeño Creek crossings, with the additional challenges of variable groundwater levels affected by recent historic high rainfall and flow in nearby drainageways, the Sonoma Volcanics, and the spatial limits of tunneling within a 20-foot gap between houses. This paper summarizes lessons learned during trenchless construction of the Happy Lane Cul-De-Sac crossing, and anticipated variations thereof that will be required for trenchless construction of Happy Lane to Orchard Avenue and Pequeño Creek crossings.

Sarah A. Mills, Delve Underground, Walnut Creek, California
Dru R. Nielson, PG, CEG, Delve Underground, Walnut Creek, California
James Griggs, PE, Sonoma Water, Santa Rosa, California

Trenchless Replacement of Aging Force Main in the Russian River Gorge
TM-T1-02, April 16, 8:30 - 8:55 am
The Russian River County Sanitation District’s Headworks, Lift Stations, and Force Main project includes replacement of approximately 10,000 feet of 8- to 16-inch-diameter sanitary sewer force main along exposed Franciscan bedrock and majestic redwood tree-covered terrain of the steep, rugged Russian River Gorge in the historic logging area of Guerneville, California. The existing force main was installed over 40 years ago to convey wastewater to the District’s local treatment plant, and includes two crossings of the Russian River: an upstream aerial crossing that is strapped to the Guerneville Bridge constructed in 1922, and a downstream, subterranean, concrete-encased crossing constructed at a depth of less than 20 feet below the river by open-cut trenching near isolated footings of the seasonally erected Summer Bridge. Because of variable manmade and geologic conditions along the alignment, the replacement force main has been designed for construction by a combination of (1) suspending the force main on the Guerneville Bridge, (2) cured-in-place pipe lining, (3) open-cut removal and replacement, (4) new open-cut trenching, and (5) microtunneling below the Russian River at its downstream crossing near the Summer Bridge. Attempts at microtunneling beneath the river and its tributaries have yielded mixed results. Channel deposits of the Russian River include open-graded gravel with cobbles and rafted logs and woody tree material at depths to 100 feet. This paper summarizes the Project’s trenchless design and lessons learned from prior microtunnel crossings of the Russian River and its tributaries.

Su Pyae Sone Soe, PE, Delve Underground, Walnut Creek, California
Dru Nielson, PG, CEG, Delve Underground, Walnut Creek, California
Christina Ramirez, PE, West Yost, Sacramento, California
Parastou Hooshialsadat, PE, Sonoma County Water Agency, Santa Rosa, California

Design-Build Coordination and Management Plan for the Bay Park Conveyance Project Delivery with Dual Trenchless Construction Methods - New York
TM-T2-05, April 16, 10-10:25am
The Bay Park Conveyance design-build project goal is to transmit up to 75 MGD of treated effluent from the South Shore Water Reclamation Facility (formerly Bay Park Sewage Treatment Plant) on the west side of Nassau County, NY, to the Cedar Creek Water Pollution Control Plant on the east side, where the existing ocean outfall will be utilized to promote the overall protection and quality of the Western Bays. To accomplish this, WSP as Nassau County designer performed the preliminary design and the Design-Build team of Western Bays Constructors, with Delve Underground as lead designer, is installing 3 miles of new microtunnel pipeline and rehabilitating 7 miles of aqueduct using slip lining on a fast-paced design and construction schedule. Discussion of the design management practices used at the height of the COVID pandemic will be highlighted from both the designer and the design-builder perspective. Included in the discussion will be design-build best practices that could be implemented during the project and those that could not, how the team was able to complete the design in a timely manner, as well as practices used to mitigate the long-lasting effects of the pandemic on the industry supply chain.

Brian Lakin, PE, Assoc. DBIA, ENV SP, Delve Underground, New York, NY
Dogancan Altinyurek, PE, Delve Underground, New York, NY
Babs Marquis, CCM, Delve Underground, Boston, MA
Christina Marino, John P. Picone, Inc.
George Gutierrez, Northeast Remsco Construction
Syed Haq, WSP

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