Utility Contractor

MAY-JUN 2018

As the official magazine of NUCA, Utility Contractor presents the latest information affecting every aspect of the utility construction industry, including technological advancements, safety issues, legislative developments and instructional advice.

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40 Utility Contractor | May/June 2018 prevents possibly undermining or dis- turbing the surrounding foundations of buildings, roads, or other structures. A positive shoring system is a critical requirement for approval from most states' Department of Transportation — including Ohio's — for any under- ground construction. Getting Started Sufficiently assured that Slide Rail met all safety requirements, ODOT gave SSI the green light to begin work on the new gravity-flow sewer. They started from bottom to top; or down- stream to upstream; or literally from the bottom of the hill at Short Street to the top of the hill at 2nd Street. Pit 1 reached down 32 ft to uncover and reroute an existing sewer line. Uti- lizing the same Slide Rail components from the first excavation, Pit 2 was dug and shored for the installation of the four deep precast sump manholes which contain the hydrodynamic separators. Pit 3 widened and lengthened the shored space just by adding a few more Slide Rail components, which allowed SSI to install inflow and outflow vaults and four 18-in. intake/outtake lines. "That's where the manifold separates the water through the four deep sump manholes and through the screening process to clean it before it reenters the new piping that we built into Short Street," Snode explained. Lastly, Pit 4 was excavated for an 18 x 11 x 28 ft tall precast chamber which intersects a 96-in. existing storm sewer and diverts the flow through a more conventional 42-in. line down to the treatment structures. The fourth pit — the largest of the four excavations — was shored with a 29 x 38 x 32 ft deep ClearSpan configured Slide Rail System. "Jeff and I looked at the ClearSpan pit at least eight times and actually had to redesign it on the fly," said Snode. "Because the big 96-in. line was not in the exact location indicated in the plan, plus everything was right in the middle of the street. It was a chal- lenge," Snode conceded. "But we were able to overcome all of that because of the flexibility of Efficiency's Slide Rail System." James McRay is the Director of Market- ing & Media for Efficiency Production – A Trinity Shoring Products company. A Northwest Florida contractor was tasked to install 180 lf of a 60-in. pipe casing via boring. The storm water project required a linear run of 60-ft with a width of 20-ft and a depth of 16-ft in a sandy clay mixture that the compe - tent person classified as Type-C-60. The project site presented several challenges that could negatively impact the integrity of the adjacent structures. The excavation was located in line to a highway overpass involving a high traffic roadway and several high - way overpass columns. The project would require a protective system that could properly accommodate a bore pit with a desired 41-ft open span work area for a 60-inch bore casing pipe running between the overpass support columns. Additionally, the protective system would need to address the pos - sibility of dewatering the open trench and dealing with a deflection of the internal bracing. The contractor called NTS to discuss a few protective options and after carefully reviewing some of the challenges, the contractor selected a site- specific slide rail and a hydraulic excavation brace combination system. Site specific engineered systems are designed for those unique and large-scale projects where poor soil conditions and adjacent structures are present. Site specific engineered systems offer a high degree of customization that allows for certain protective devices to be customized for unique applications. For the boring pit, it was determined that a slide rail system would be the most optimal solution that could provide a large open span work area if sup - ported by an excavation brace. A slide rail system is a versatile protective underground system that can be used for a wide range of applications and paired with several modular components. A hydraulic excavation brace can be used as a four-sided application composed of adjustable hydraulic brace legs designed to support rectangular and square underground excavations. For those complex jobs, braces can be used in additional polygons such as 5 sided or 6 sided excavations. The contractor was extremely satisfied with the safety provided by the site specific engineered system, as it provided a practical solution during the pipe casing installation. The excavation was located in line to a highway overpass involving a high traffic roadway and several highway overpass columns. Site-Specific Engineering for Unique Pipe Casing Installation

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