The symmetrical bi-cylindrical structure is a closed shell composed by two unclosed arch shell.
该结构是由两个对称非闭合大弧度圆弧横截面柱壳对接而成的闭合柱壳结构（简称“双圆弧柱壳”）；
2
Camel Hill looks to my eye like a fist, closed except for a thumb pointing to the sky, while Elephant Trunk Hill looks like a simple arch.
在我看来，骆驼山就像一只四指朝天的拳头，而象鼻山看起来像是一座简陋的拱桥。
3
To construct the 1, 060-foot-long arch, they cast 24 feet of concrete at a time, while a separate, temporary cable-stayed bridge held up the unfinished ends until the gap was closed this year.