A South Carolina contractor was tasked with the construction of two, new cast-in-place structures to support existing and future sewer infrastructure. The new structures would be five-sided connecting to an existing 42-inch to a 54-inch sewer main with the second structure to be tied into a 64-inch sewer main.  The project required two similar excavations with a linear run of 24-ft, a width of 24-ft, and a depth of 16-ft. After carefully examining the soil, the contractor’s Competent Person classified the soil as silty sand Type C-80.
The excavation site was located adjacent to a creek, which made it difficult to control the rising groundwater. The contractor dewatered and installed a well-point system to facilitate the working span excavation that would be required of the project. The job site also had a limited amount of workspace, which reduced the range of protective systems for the project.

The contractor contacted NTS to discuss the project and potential protective systems. After carefully reviewing and determining the challenges that the site presented, the contractor selected a site-specific engineered, four-sided slide rail system with steel plates as sheeting along the system’s guide frames. The slide rail system provided the necessary open-span area for the two new cast-in-place structures to be constructed. The steel sheeting guide frame system allowed the contractor the flexibility to tie in the existing lines to the new cast-in-place structures. The contractor was extremely satisfied with the performance and safety provided by the protective system.