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Page:Popular Science Monthly Volume 89.djvu/878

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A Floating Road for Automobiles

A plank roadway built over a California stream enables automobiles to cross under their own power

���Above: Light cars pass over the semi-floating bridge at a speed of about ten miles an hour

A SEMI-FLOAT- IXG bridgf, oiu luiiidrc'cl and lour feet in Icnictli, has l)(.-i.'n ron- structed l)y the California Hii;h\va\- Com- mission over Castaic Crci'U on ihc rcrcnll\' opened I-os Angeles to Bakcrslicld ronte. The ford at this jioint has long been a menace to automoljile travel, because of the varying depth of water and the extreme- ly sandy bottom. Teams ha\e, therefore, been maintained at the crossing In- the county to tow autom()i)iles across. While effective, this method was very unsatis- factory.

To relieve this condilion a sinii-lloatiii.u liigh\va\' bri<lge was constiiiclcd. A plank road was built in sections and held together by cables in such a way that a good surface would be continuous across the ford. Tin- depth of tile water was thus decreased, not only by the thickness of the plank ,uid stringers, but also by the .imounl wiiii h the tires would otherwise sink into the Mtfi, sandy boitom.

Afic-r the M'ctions were bnill on shore and llo.iled to ihe crossing, ihev were held

��At left: The bridge plans. The supporting ca- ble was twentj--five feet above the plank sections

together b\' a three- quarter-inch cabli' threaded through c\x-bolis in each section. At twelve- foot intervals the cable was attachetl b\- one-half-inch cables to a seven-i'ighth-incli c.ible stretched across twent\--hve feet above the plank sections, and drawn sulliciently taut to support it four feet above high water.

One end of the bridge was securelv anchored with a three (luarter-inch cabh clamped to the e\'el)olt on the last twelve- foot section, and m.ide fast to the shore. The opposite vnd was lightly secured with a one-half-inth cable to the shore. This was done so that in case of high watei carr\ing drift against the bridge, one end would be rele.jsed from its anchoring I>oint, allowing tlii' bridge to swing around to the opposite bank.

The bridge w.is ('omi>leled in two d.iys .11 ,1 cost of ?i7.5o for labor and 5i-'> for m.ilerial, freight and I'.irtage. Light car.-- CHI p.iss owr it at a speeil of about ten miles .m hour without submerging llie dilTerenl sections .is the\ p.iss over.

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