In-water work restrictions are so tight in the salmon-filled rivers of western Oregon that the Oregon Dept. of Transportation decided to employ a top-down bridge construction method to replace a section of Interstate 84 east of Portland. If all goes well, say ODOT officials, the method may be adopted on a more frequent basis.

Crews from Hamilton Construction Co., Springfield, Ore., have built a pair of gantry cranes in preparation for work at the confluence of the Sandy and Columbia rivers. Using twin 250,000-lb cranes, each weighing 100 tons and spanning 90 ft, construction crews will not need in-water work bridges to place a total of 49 steel girders for both the westbound and eastbound spans, says Wendell Snook, Hamilton's project manager.