[建议]：美丽的大坝，大家跟贴呀

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Multiple Arch
The first multiple arch dam of reinforced concrete had been completed in 1908. It impounded the Hume Lake fluming reservoir on the Ten Mile creek in the California Sierra Nevada Mountains. The dam was designed and supervised during constuction by John S. Eastwood (1857-1924). He also designed the Big Bear Valley dam in the San Bernardino mountains. Eastwood's designs were very economic: the required less concrete than an equivilant gravity dam and cost less, too. Overall, a dozen multi-arch dams were built in the following decade and a half according to Eastwood's design.

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A decidely larger arch span of 54.9 m was acheived in 1928 at the 76 m high Coolidge Dam in Arizona. This was the first application of the double-curved dome structure to buttress dams. Coolidge Dam provides water for irrigation, power, and recreation.

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After World War II, large-span multiple-arch dams were pursued further by the prominent French dam designer Andre Coyne (1891-1960). After the war, several of them were built in France, among such sizable structures as the 88m high Grandval Dam built in 1959 with a 50 m span. However, Coyne's most important project of this type was built in the years from 1961 to 1968 in northern Canada. On the Manicougan river in Quebec was built the Daniel Johnson dam. It was an unprecedented 214 m high with a central span of 162 m and smaller side spans of 76 m each!! Unfortunately, the elegant structure was plagued by numerous cracks.

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Flat Slab Buttress
The hottest competitor to multiple arch was the type of flat slab buttress designed and patened by Nils F. Abursen in 1903. Abursen's design took full advantage of the stabillizing effect of the vertical water load on the strongly inclined upstream face, which required a minimal buttress thickness per unit of dam length. The Abursen dam type soon became quite popular and, by the end of the 1920's, more than 200 had been constructed, thus outnumbering multiple arch dams by far.

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Contiguous Butresses
There was an introduction of a new kind of design in which the arches or slabs as upstream closures of the intermediate spaces between the buttresses were replaced by a thickening of their heads to make them contiguous. The Dixence dam in Switzerland had II shaped buttresses. It was the world record in height for a buttress (87m) dam until after WWII. This dam has now been submerged by the reservoir from the Grand Dixence gravity dam in 1957.

huang961014

It's beautifull!真是赏心悦目！

freestart

我也帖几张：

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huang961014

哇塞，更美，都是你们自己设计的吗？

freestart

最初由 huang961014 发布
[B]哇塞，更美，都是你们自己设计的吗？ [/B]

都是平常收集的照片，老外的。

gong0012

我的工地照片