A Northern Texas contractor had been tasked to install a 24-inch natural gas pipeline and tying it into an existing line. The project required a linear run of 35-ft with a width of 12-ft and a depth of 9-ft. After carefully examining the soil, the Competent Person on-site classified the soil as semi-moist cohesive Type-C-60 soil.
The site presented several challenges with the work area and nearby structures. The new 24-inch pipeline would run under an existing road and turn at a 45-degree angle adjacent and parallel to the busy roadway. The project would require a system that could provide an open span work area for the incorporation of the new 24-inch line and the existing 24-inch natural gas line while providing the soil support needed to preserve the integrity of the existing roadway.
After carefully evaluating some of the challenges; the contractor elected to use trench shields for the project. As contractors know, a trench shield is a protective device composed of engineered steel panels coupled with steel spreaders to provide horizontal support of the panels. Trench shields are available in a wide range of sizes and can be configured with lightweight single-wall or heavy-duty double-wall shields. The contractor was extremely satisfied with the performance and safety of the trench shields during the tying installation.