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Show 1942 Grand Coulee Dam - A decade of big dams drew near its close when in early 1938 Utah and associates, in a joint venture group known as Consolidated Builders, moved to the Upper Columbia River, 90 miles west of Spokane, Washington, to complete Grand Coulee which in 1954 was still the world's largest concrete dam. Foundation work, which included freezing a whole hillside to prevent slides, had been completed by another association of contractors. The job that followed was largely a mammoth task of organization of the most efficient and largest concreting organizations yet designed. Extending three-quarters of a mile across the Columbia River, 550 feet high, 500 feet thick, containing when finished three times as much masonry (10,230,776 cubic yards of concrete) as had been placed in a single structure in the hostory of man Grand Coulee is a statistician's dream. For in- stance, 2, 200 miles of one-inch steel pipek enough to form a solid line from Seattle to St. Louis, were embedded in the mass, carrying chilled water to cool the concrete which otherwise would have been coring and cracking 150 years after completion. Less than 12 weeks after Consolidated Builders were awarded the contract, a new steel construction trestle, 200 feet high and 3, 600 feet long, was erected across the river on the downstream. Along this trestle moved two 270-ton, double-cantilever cranes (improperly called hammerheads) with 356 foot booms, to place 6,000,000 cubic yards of concrete, and thousands of tons of reinforcing steel and machinery in the dam. Nine Hundred tons of concrete poured into the dam each hour, day and night, for 26 months. A new all-time record for concrete pouring was set when 20,697 cubic yards were poured in one day and night. |