Page:Popular Science Monthly Volume 90.djvu/275

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Fighting the Ocean with a Big Grandstand

A great beach esplanade has been erected which will provide much needed protection

���The bleacher seats, which have a minimum concrete thickness of twelve inches, rest on sand overlaid with eighteen inches of solidly packed clay. At the top is a wide promenade

��THE winter storms and equinoctial tides which have caused so much damage to the wide stretch of sandy beach which is San Francisco's pride have received a permanent set-back to their destructiveness. A great esplanade, a kind of glorified grandstand, has been erected which is designed to withstand their attacks. On the ocean side the structure consists of five steps, or bleacher seats, anchored in solid rock. The plane of these bleachers is inclined at about twenty-five degrees to the horizontal. Supporting the

��bleachers transverseh- at twenty-foot in- tervals, exeept at the stairways, where they are on ten-^oot centers, are H-beams twenty- by forty-three inches in section and tw«nty-seven and one half feet long.

From the boulevard or land side the esplanade has the appearance of a massive concrete wall three and one half feet high. The top of the parapet on the ocean side has been made slightly concave, so that as the waves rush up against the wall the water will be thrown back upon itself and will thus lessen the force of the succeeding waves.

���The entire mass oi concrete is tied together with reinforcing iron in such a way that it is practically a solid fortifying wall twenty-five feet in depth and twenty-seven feet wide


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