Complex Project Requires Slide Rail Shoring System

November 2009 Vol. 64 No. 11
Chris Acord is the construction manager for Pipeline Utilities Inc.

Reflecting upon the planning phase Sondergard said “we felt immediately that the slide rail system would easily accommodate the poor soil conditions we would encounter on this project. Slide rail systems were designed, in part, to accommodate very poor soil conditions, and often shine on these job sites. The slide rail system's efficiency becomes very pronounced in bad soils because you can advance the panels along the rails, ahead of the excavation's cut, which helps to prevent a soil raveling. In addition, the system has the benefit of being positive shoring. Positive shoring is a system which acts to prevent a soil collapse, as opposed to just protecting employees in the event of a soil collapse – the role of a standard trench shield. The benefit of positive shoring becomes paramount when dealing with adjacent structures, tight job sites or right-of-way issues.”

In addition, the poor soil conditions exert a greater soil pressure against the system. This effect is similar to that of the depth and together they both increase the stress on a slide rail system. The SBH slide rail system is built to handle these intense soil pressures and can comfortably achieve the 35-feet of excavated depth needed on the project. Large triple slide rails were dug into the ground, and slide rail panels advanced along tracks in the rail to provide soil protection to the full length of the excavation.

Coble Trench Safety features the SBH slide rail system, which provides a rigid system of strength while also being highly customizable and adaptable to individual job sites. This customization was needed during the installation phase. Linear rails were driven into the ground and the cross bracing system took the form of a linear rolling strut. During installation, the linear rolling strut advances along the rail to prevent "toe in" of the system. Once the system is fully installed to the full depth, the strut can be rolled up to provide additional vertical clearance as needed. Using site specific engineering, it was possible to achieve the necessary 102-inches of vertical clearance with the site conditions present and ultimately provide the optimal method of shoring the excavation.