Trench Shields & Arch Spreader Combination Assists on Water Reclamation Project

An Arizona contractor was tasked with the construction of a multistory new mixed use development. The new construction would require an underground storm water system that could properly manage the water runoff from the new structure. The underground site would require an excavation cut with a linear run greater than 800-ft for which the contractor’s Competent Person had classified the sandy soil as Type C-60.

The contractor’s initial approach required benching both sides of the excavation walls avoiding the use of an underground protective device. This option was soon eliminated as the contractor was forced to construct two new pylon structures prior to the storm sewer installation phase. The pylon structures were poured-in-place adjacent and parallel to the pre-determined excavation area. The contractor contacted NTS for a solution and after reviewing some cost-effective solutions, the contractor elected to use a trench shield with site specific engineered arch spreaders. Trench shields are a cost-effective solution that come in a wide array of sizes. The custom high clearance arch spreaders allowed the contractor to use conventional steel spreader pipe with custom spreader adapters to provide the necessary high clearance shore, while also managing the weight of the arch spreaders. Conventional steel arch spreader bases can often be very heavy, which may limit the use depending on machinery on site. These custom arch spreaders worked within the lifting machinery on site and delivered the contractor a solution with the requisite vertical clearance. Once the culvert installation is completed, the new mix use development will efficiently collect and manage the storm water while ultimately reducing the stress on the existing lines. The contractor was impressed with how easy the trench shield was able to adjust along the excavation as the culvert installation progressed.