A major energy provider in the state of North Carolina needed to remove and replace an existing 8-ft diameter oil water separator tank. Oil water separator tanks provide a vital function of removing pollutants before it’s discharged into a nearby body of water. The contractor tasked with the project calculated the area to be excavated 100-ft long, 20-ft wide, and 22-ft deep. The Competent Person on-site classified the dry, sandy, clay mix with large granite boulders as C-60. Due to the presence of an operational power station and the instability of the surrounding soil the owner of the project would not allow a large footprint nor the use of a vibratory hammer. With the stringent parameters set by the utility company, the site would require a site-specific shoring solution to meet the demands.
Heeding the concerns of the utility provider; the contractor met with the local NTS engineering team. In collaboration with the project owner and contractor, the NTS engineering team designed a site-specific slide rail shoring system. The slide rail shoring system is a modular component system that can be quickly installed for pit or linear applications. This protective system can be paired with a steel sheeting guide, rolling struts, arch spreaders, hydrostatic braces, wales, or clamped steel girders.
For this specific project, the slide rail system was paired with a steel sheeting guide frame, rolling struts, and steel girders as tie-backs. To install the slide rail system, the 
contractor excavated the site and installed each linear rail and panel via dig and push to minimize the vibration and soil disturbance. The installation of the shoring system was a slow, and arduous process due to the occasional large granite boulders that had to be removed before the linear rails could be pushed to depth. The combination of the steel guide frame and rolling struts would provide additional support for the excavation while the contractor removed the old tank.
Once the tank was removed, steel tie-backs were then placed outside the linear posts and secured with clamps. The steel tie-backs would allow the contractor to remove the rolling struts. With the rolling struts removed, the slide rail pit could span into 5 bays leaving 3 of the bays open. The open bays would create a 54-ft linear workspace allowing the contractor to quickly install the 10.5-ft diameter oil water separator tank After the project is finished, the utility company will have the capacity to safely and efficiently discharge the water into the local waterway.
