Location:
Pittsburgh, Pennsylvania

Project: 
10 Foot Diameter Access Shaft to an Existing Storm Sewer Tunnel

Situation:
At 10 feet in diameter and approximately 100 feet deep, some of the greatest challenges with this project were logistical. The city streets were narrow and congested making it difficult to get our large diameter drilling tools and prefabricated liners to the site. Additionally, the owner was seeking assurances from the prime contractor that the shaft works were being completed by an experienced subcontractor.  

The project included setting surface casing through saturated overburden to a depth of approximately 65 feet and then completing rock excavation to a total depth of approximately 100 feet.  

Solution:
SDI utilized specialty fabrication on the steel liner in combination with both auguring and vibratory hammer techniques to set the surface casing to the top of competent rock.  A concrete plug was then set at the interface between the overburden and top of rock.  Reverse circulation drilling techniques were used last, to complete the works to total depth.

Results:
SDI coordinated project management to overcome both the challenging urban environment as well as ground conditions leading to a safe and successful development of the shaft.