索膜结构，索膜结构，
当然是在索成形以后，才铺设膜，大家讨论了这么多的膜的施工等等，
我想问问，索穹

错误！不要望文生义
正确的施工顺序是先铺膜，后挂索。在膜的控制边界都固定好之后，通过张紧索来向膜施加预应力

这样说来还是索是主动的，膜是被动的。
我想这个里面问题有几个，
一、膜的裁剪，只要膜的裁剪到位，索一张拉，膜就到位。
二、索的设计，索的设计包括，索的拓扑设计和所松弛长度的设计（也可以认为是索的裁剪）。
三、索和膜的边界耦合。
上述的三个问题中，我们可以看出索设计的重要性，只有索设计好了。才能使整个结构有了力学和建筑的完美。

好象索是被 “缝”在膜上的
重要的是应力的设计涉及到结构的找形和刚度

Allow me to give a brief description how to erect a索穹

我自己的索穹顶施工方法：8D
(1) 所有单元按照空间拓扑关系在地面连接在一起，桅杆穿过下部节点（见下图）中间的孔与上部节点临时铰接固定。所有索单元均可按设计长度下料，只保留某些索可以适当调节索长；
(2) 将整个“结构”吊起，由于桅杆尚不起作用，结构除自重外几乎不存在预应力，故容易使最外圈脊索和下斜索与外环梁连接就位；
(3) 利用张拉设备将最外一圈桅杆从下部节点环中“顶出”一定长度；
(4) 再将第二圈桅杆从下部节点环中“顶出”一定长度，依此类推，从外到内分批加长桅杆直至到设计位置。
(5) 最后将桅杆与下部节点可靠连接，调整某些索的长度，使整个结构到设计形状，即完成索杆部分施工。
  
敬请davidchen兄赐教！

Hi, sphinx. Your idea is definitely one of the many possibilities, but the implementation could be cumbersome. The erection method used for Crown Center @ Cumberland County Coliseum Complex, Fayetteville, North Carolina in 1997 was vastly different from the one for Gymnastics and Fencing Halls, Seoul, Korea in 1985. The learning process helped to cut down the construction time and manpower. For the 2 almost identical structures, it took more than 120 people for 6 months to erect Gymnastics Hall but only 25 people for 3 months to erect Taoyuan Arena.
  
As you observed, when there is no or little pre-stress in the cable dome system, the structure is rather unstable. Telescoping the struts will require people to work in the air with heavy equipments without solid footing. There is also a system buckling possibility. Cranes could be used to hold up top connections in place, how practical is this? There are 96 top connections in Tropicana Field, St. Petersburg, Florida.
  
Site constrain is another problem. Usually the floor area is much smaller than the roof over it. There is not enough space to spread out the cable network. Picture 1 can illustrate the situation for you.
  
These 3 pictures were taken at the beginning of the Taoyuan Arena roof erection in 1993.

Picture 1

Picture 2

Picture 3

Sir DavidChen, Thank you for your quick response!
  
From what you said, I feel all of domestic researchers in this field lack the experience of practice. All of us are eager to hope we can collaborate with you to practise this structure in Beijing for the 2008 Olympic game.
  
By the way, as known, very extraordinarily, the Crown Coliseum is covered with metal roof deck instead of the fabric roof. Can you generously show us the connection details? You said its erection method is very efficient, compared with one of Gymnastics and Fencing Halls, Seoul, Korea in 1985. is it only shorten the outer-most diagonals to introduce the pre-stress?