Page:Final Report - The Columbia River Interstate Bridge.pdf/39

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SPECIAL FEATURES OF DESIGN

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BUILDING THE PIERS.

Pile-driver equipment used to sink the foundation piles for the glen. The leads are 122 ft. high above the water; the overhang is 2 ft. in front of barge. Equipped with two hoisting engines, two pumps. and 800-H.P. boiler.

The marked economy of design came from a thorough study of local conditions and local possibilities for materials, and a fitting of the design and the plans to realize every possible advantage so offered. Possibly nowhere in the world are extreme1y long timber piles available at as low a price as at this bridge site. Not only the river bed conditions already described. but this exceptional facility for securing such piles at reasonable cost was a considerable factor in determining upon the exact type of piers to be used. As has been described, the piles as delivered were single sticks from 120 ft. to 125 ft. long. The specifications described the special equipment, which would be

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