Improved Ribbon Bridge Interior Bay

The Improved Ribbon Bridge (IRB) is a modular floating bridge. A complete IRB consists of a ramp bay at each bank and  interior bays to complete the bridge. Individual bays may be joined to form a raft for ferrying operations. Each bays is transported in a folded position on a Common Bridge Transporter . The bays unfold automatically in the water when deployed. The IRB mission is to provide a continuous roadway or raft capable of crossing vehicles over nonfordable waterway.

This Comes in 4 parts so you can choose to have it open or closed Just use a U shape stiff wire to connect the parts  and you can open or close them at will.

Here is the other part of the IRB:
https://www.shapeways.com/product/5JJFGECPQ/improved-ribbon-bridge-ramp-bay