Mega Brace Shoring Provides Unique Solution For Water Project

By Jeff Griffin, Senior Editor | December 2010 Vol. 65 No. 12

Projects requiring excavation are recognized as among the most dangerous in construction, and protecting personnel who must work in trenches and surrounding areas from cave-ins is a priority with life and death implications.

For small jobs, trench protection may be as simple as dropping a trench box into the excavation. Larger jobs are more complex. A major project often requires extensive engineering and the use of specialized shielding and shoring.

North America’s largest rental supplier of trench safety systems and products is United Rentals. The company also is a provider of pre-construction planning and turnkey installation and removal services. United Rentals operates more than 50 trench safety rental branches that offer the latest technologies in steel and aluminum trench shields, aluminum trench shores, steel sheet pile with modular waling systems, steel crossing plates and custom slide rail systems.

Recently, United Rentals provided a Mega Brace shoring system for an Xcel Energy project in Colorado to pull water from the South Platte River downstream from Denver at the discharge point of the Denver Metro Wastewater Treatment Plant, and divert it to the company’s Cherokee Power Plant approximately half a mile away.

General Contractor was Garney Construction, Littleton, CO. Working as a subcontractor to Garney, Territory Unlimited, Berthoud, CO, built a grouted boulder drop structure in the South Platte River that was integrated with a Garney-installed concrete diversion structure and 170 linear feet of 24-inch ductile iron pipe to bypass water to a pump station wet well structure.

Territory Unlimited installed the Mega Brace system with teams of United Rentals personnel providing expertise on site throughout the project.

Decisions
The Mega Brace system was engineered by D. H. Charles Engineering, Santa Rosa, CA, and was used in a 30-foot deep, four-sided 35-by-30-foot excavation for construction of a 25-foot high, 25-by-20 foot concrete wet well structure, said Kris Graham, United Rentals outside sales representative, Denver.

Graham said a sloping system was ruled out because it would have required removal of more than 4,666 cubic yards of soil, compared to the 1,166 cubic yards for the Mega Brace.

Other bracing systems were evaluated and rejected.