Presentation on the planning, engineering, design, and construction using microtunnel technology to install over 1,550 linear feet of 42-inch gravity sewer pipe in some of the most challenging geologies in New York State, including environmental and site conditions. GHD was retained to design a 10,000 linear foot, 42-inch gravity-type interceptor sewer to parallel an existing interceptor to increase system capacity. The site required four separate trenchless installations to cross Interstate Highway I-90/790, North Genesee Street, Reels Creek, and Leland Avenue, totalling over 1,550 linear feet. The four crossing sites presented many challenges including low bearing strength soils, weak soils with high organic content, high groundwater, deep installations, close proximity to high voltage power lines, a constrained site, wetlands, and limited site access. GHD launched an extensive soils and hydrogeologic investigation of available trenchless technologies. Given the site and pipe service conditions, deep installations, and required accuracy of the gravity sewer installation; microtunneling and direct-jacking of centrifugally cast fiberglass reinforced polymer mortar (CCFRPM) pipe was ultimately selected as the preferred method to complete the crossings. GHD was required to coordinate the acceptable means and methods proposed for each trenchless crossing site with owners of the property, the right-of-way, and the roadway prior to specifying microtunneling. Construction engineering was also performed to ensure an accurate and well-planned microtunnel submittal would be developed, prepared, and executed. GHD will present the trenchless crossing selection process as well as critical success factors utilized through the engineering, design and construction phases.
展开▼
