The transfer from the barge to the artificial island, which is a par of the Parallel Thimble Shoal Tunnel Project in Chesapeake, Virginia, US, was facilitated via a multi-purpose steel trestle. This structure was designed by Intesca-Inarsa & Dr Sauer & Partners to fulfil a variety of functions:

• Increase of space on the island for heavy truck traffic
• Accommodate a large crawler crane for TBM delivery (maximum lift load from barge 585 kips or 2,600kN)
• Due to space constraints one rail of the portal crane is located on the trestle and the other one on the island
• Storage of TBM segments during tunnel construction.

Besides the steel trestle, the scope of services included the design of a variety of other structures including a 500ft long muck pit, a TBM jacking frame and cradle, numerous shallow and deep foundations, shoring designs, as well as a smaller steel trestle on the Northern Island.

The project's lead designer Mott MacDonald worked with Dr Sauer & Partners to make sure all temporary and permanent structures fit together nicely. 

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