In a move never attempted before, US-based J A Jones Constr-uction Company, together with the US Army Corps of Engineers, is undertaking the remote construction and floating of a dam.

First of all, the company will build a dam at a dry dock near the Ohio river. The pre-cast dam will then be floated in two parts 43km to the dam site on the Monongahela river near Pittsburgh.

The largest of the two segments of the new Braddock dam will be 102m x 131m and weigh 11,000t. The smaller section will weigh 8500t.

The two segments, made from 438 reinforced concrete panels, have been interconnected in a grid with a continuous concrete slab underneath, creating a boat-like structure with airtight cells inside. Once the structure is in place at its site, the interior cells will be filled with water to sink the dam onto a pre-constructed foundation at the bottom of the river, where it will be sealed.

Finally, the water inside the dam will be replaced with concrete.