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Show BRIDGE BUILT TO WITHSTAND FLOODS la certain parta of tbe West and Middle West streams that are ordinarily ordinar-ily very small become raging torrents after a heavy rain. Since It Is neither practical to build a high-water bridge, because of the cost and the amount of filling that St iff Tvft -i SI Concrete Bridges Becoming Popular. would be necessary In a flat, level country, the low-water bridge has come to be quite popular. It Is built of concrete and high enough to allow the flood waters of an ordinary rain to pass under It. But more water sends the stream above It and drift and trash are thus floated above It. This removes one of the great dangers to bridges across swlft-rising swlft-rising streams. The drift lodges against the piers and forms a dam. The weight of the water behind It develops de-velops more pressure than the bridge cun stand and It Is destroyed. |
