A contractor was installing footings for what will become a five-story parking garage to support a new ten-story building being built approximately 75 yards from the parking garage site.  The contractor had classified the red, clay soil as a Type C-60 soil and this portion of the project would require a 16-ft square excavation to a depth of 16-ft as well.

In addition to the new ten-story building under construction, there was also an adjacent retaining wall that required additional consideration when selecting the appropriate protective system. The contractor contacted NTS to see what equipment solutions may be available for the project. After careful review, the contractor elected to use steel
trench shields. The contractor’s engineers reviewed the pressure ratings of the trench
shields against the pressure that would be exerted by the retaining wall to determine that the trench shields would provide a safe work site for the crew. In addition to the soil support needs, the contractor also needed a four-sided protective system. The contractor was able to achieve this by installing the trench shields with conventional spreaders and then capping the open ends with trench shields that would “kick” off the ends of the trench shield. The design was allowed by the manufacturer’s tabulated data and provided an efficient method of protecting workers while providing a 16-ft square open span excavation for the work to be performed. The contractor was very satisfied with the system’s configuration and performance for the project.