- Submarine Construction Platforms
Of all mankind's inventions, few are more challenging to build than a nuclear-powered submarine. Beginning January 2009, General Dynamics' Electric Boat expects to speed up that process when its crews begin working from two new football-field length concrete-and-steel platforms at its nuclear submarine construction facilities in Groton, Conn.
Designed and built by Burns & McDonnell, the two-level platforms address a host of issues that have historically complicated submarine construction.
"For the past 100 years, crews have worked from the ground level, where they had to navigate a maze of utilities, cables, equipment and materials needed in the fabrication process," says Jerry Shirley, the project's design manager for Burns & McDonnell. "Temporary scaffolding has been needed just to access the sub."
Electric Boat's new platforms more than double the amount of work space available by permanently housing utilities and equipment on the upper deck. A walkway on the lower level gives crews access to movable gangways that connect to the submarine.
"The platforms make sub construction considerably easier to stage and sequence, while producing a safer work environment," says Matt Carpenter, construction manager on the $14 million project. Electric Boat is able to construct two subs at a time with the platforms.
Professional Services Provided
- Preliminary design and budget estimating
- Final design, plans and cost estimating
- Design-build construction services
Close coordination of building technical requirements and equipment interface requirements were necessary throughout the project.
- The foundations consist of steel reinforced pile cap foundations, each on three or four micropile shafts.
- The platform structures consist of 6" and 8" cast in place concrete decks on metal structures. The two structures required approx. 700 tons of steel and 870 cubic yards of concrete.
- Custom-designed and fabricated personnel brows allow foot traffic access from the access deck to topside of adjacent submarines.
- Custom-designed and fabricated utility brows allow for routing for portable utilities from equipment on the upper utility decks to the topside of adjacent submarines in an organized and safe manner, away from general foot traffic.
- New lighting provides illumination for new platforms as well as significant improvements in lighting levels for adjacent areas of the existing building.
- Mechanical and electrical service ports on the platforms allow for safe and convenient connections serving submarine assembly activities and portable equipment located on the utility deck. The following utility systems were provided:
- Low pressure compressed air
- High pressure compressed air
- C5 gas
- Fresh water
- Pure water
- Fire protection
- 13.8-kV electrical
- 480/277V electrical
- 208/120V electrical
- Casualty control and communication
- Fire alarm
- Each platform is equipped with a 3,000-pound personnel elevator.
- Each platform is equipped with an 8,000-pound freight lift.
- Construction took place within operating facility immediately adjacent to submarine assembly activities.
- The platforms are in partially open buildings that were originally constructed in the 1960s and 1970s. Some selective demolition of the existing structure was required to allow for construction of the new platforms. Various demolition and relocation of utilities was also required.
- The existing floor slab has a high service load. Demolition and reconstruction of the existing floor slab had to occur in a way that the original load ratings of the floor were preserved.