Pier 31 Replacement. Groton, Connecticut.

A modern, first class replacement of the original Cold War era pier, the new Pier 31 is a 500 foot-long, open concrete pier, located at Submarine Base New London (SUBASE) in Groton, CT.

WRA provided full-service engineering services for the demolition of the existing pier and design of the new pier, which was designed specifically to accommodate the Los Angeles and Virginia class attack submarines berthed at SUBASE. The new pier consists of reinforced concrete deck and supporting beams and pile caps. Concrete-filled steel pipe piles are secured to bedrock beneath the river bottom via rock sockets. Full utility hookups are provided, including power, water, and sewer. Due to the need for updated berthing accommodations for the Los Angeles and Virginia class submarines, the Pier 31 Replacement project was among the most important capital improvement projects at SUBASE.

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Services Performed

Project Highlights

Marine

WRA performed full berthing and mooring analysis of the Los Angeles and Virginia class submarines for reactions on the fender piles. Additionally, a new FRP composite camel was designed to absorb the berthing energy and transfer to the piles and pier superstructure.

Structural

The new pier consists of reinforced concrete deck and supporting concrete beams and pile caps. Precast concrete planks were utilized as ‘stay in place’ formwork acting integrally with cast in place concrete poured on top. Concrete-filled steel pipe piles are secured to bedrock beneath the river bottom via rock sockets near the shoreline. The pier is equipped with bollards and cleats, a polymeric pile fendering system, rotatable permanent brows for boat access, and jib cranes for ship-to-shore po

Electrical

Electrical service was supplied from a base-wide 13.8kV distribution through two SF6 vacuum fault interrupter switches at the head end of pier. Switches feed two 2,500kVA double-ended substations located at inboard and outboard ends of the pier.