As Amirkian as Apple Pie – The Seabees and the AMMI Pontoons, Part 3

The Ammi Pontoons were a great addition to the Navy’s arsenal but more importantly were the incredible things they could do when strung together. Different ideas were tested out and used, such as floating docks, transferring platforms, and mobile bases. One of the most useful inventions that pontoons were used for is what is called the Ammi Bridge.

Bridge construction through the years has followed a somewhat conventional pattern of stylized construction, using conventional material and methods. The AMMI Bridge further decreased the installation time and procedures required for advanced base bridge construction. The bridge evolved from the AMMI pontoon, with its “biserrated orthotropic” framing member and built in spud wells. It was these tube pile spud wells that marked the principle distinction of the AMMI Bridge.

The spud wells – no not a type of potato – 2 per section, were 20 inches in diameter and extended from the pontoon bottom to 4 inches above the deck surface. Using the spud wells as tube pile leads, 18 inch diameter steel piles were driven to ensure secure foundations for the elevated bridge. Utilizing pile caps, with appropriate tackle and winches, the pontoon was elevated to the pile cap and secured in place to the piling.

Men at Work Too

One of the first examples of the AMMI Bridge in action was during Vietnam by Naval Mobile Construction Battalion (NMCB) 53 in 1967. Approximately 150 linear feet (LF) of bridge were erected on Route 1 south of DaNang and 650 LF were erected across the Perfume River west of Hue. At one place in the crossing the river was 37 feet deep. The height of the bridge deck over normal river level was 21 feet. But during the winter monsoon the river rose to 5 feet over the bridge deck. The ground appeared to be washed out, but the bridge was undamaged and remained in full operation. In March 1969, a Viet Cong saboteur severed one pipe pile of this bridge; however, the bridge remained in partial service and was restored to full traffic within a few days. This enabled supplies to still reach their destination without the delays and setbacks that a normal pontoon bridge would have taken.

Variations on the Plank Type Pontoon Bridge

The bridges and pontoons designed by Dr. Arsham Amirkian were so revolutionary that they continue to influence and inspire bridge and pontoon design to this day. One example of this is the Navy’s Elevated Causeway System-Modular (ELCAS (M)) These bridges were used in Kuwait to support Joint Logistics Over the Shore (JLOTS) and quickly offload the backload of thousands of cargo containers used to hold military supplies and equipment. The bridge below was built at Camp Patriot in Kuwait by ACB-1 in 2003.

Camp Patriot Kuwait

Dr. Arsham Amirkian’s legacy continues to live on, what he will inspire people to do next is anyone’s guess!


150225-N-JU810-001Meet the Archivist: Ingi House
Ingi House is originally from Kansas where she got her B.A. in history from K.U. and M.L.S. from E.S.U. After working for the Dole Institute of Politics she moved to the East Coast.  In D.C. she worked at the National Archives and Records Admiration and then at the Defense Acquisition University where she became a Certified Archivist. Her continued enjoyment of military history lead her to switching coasts and coming to work for the Seabee Museum where she is collection manager for the archives and records manager liaison

One comment on “As Amirkian as Apple Pie – The Seabees and the AMMI Pontoons, Part 3

  1. David Ligon says:

    Dear Ingi,
    I was a Seabee on a six- month detachment called Detachment Delta with ACB-1 at Cat Lo,Vietnam between sometime between June 1967 through Dec.1967. My job as a BU was to paint the AMMI Barges our SW ‘s had built. These came in segments similar to a worm that were welded together. We were told this was an experiment that a Dr in California had designed. We built about 8 of them during this six month period.


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