Scientific American Supplement, No. 458, October 11, 1884 by Various
page 74 of 144 (51%)
page 74 of 144 (51%)
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which was 45 meters to the right of the pier, and upon combining the
horizontal stress that produced it with that of the loads, the stress exerted upon the body may he deduced. But this hypothesis seems to us scarcely tenable, especially by reason of the great stress that it would have taken to lift the superstructure. On another hand, it was possible for the latter to slide over one edge of the pier, and this explains the horizontal distance of 45 feet by which its center of gravity was displaced. It is probable, moreover, that the superstructure, before going over, moved laterally upon its temporary supports. The girders were, in fact, resting upon rollers, and the roller apparatus themselves were renting upon wedges, and there was no anchorage to prevent a transverse sliding. Under the prolonged thrust of a very high wind, the superstructure, by reason of its considerable projection, must have begun to swing like a pendulum. These oscillations acquired sufficient amplitude to cause the superstructure to gradually move upon its rollers until the latter no longer bore beneath the webs. The flanges therefore finally bent upward where they rested upon the rollers, through the action of the weight which they had to support, and the entire superstructure slid off into space. An examination of the bent pieces seems to give great value to this hypothesis.--_Le Genie Civil_. * * * * * |
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