今有一看台飘蓬，建筑师说不喜欢帐篷形式的， 非要做平， 采用膜材，可行吗，哪位遇到过此类工程，考虑平面膜材无刚度， 极易积水，有风时震动会很厉害，觉得此造型采用膜结构不合适。

悬挑多长？

It is not to my liking designing a flat membrane canopy structure, but it is possible and had been done many times before. This stadium was completed in 1990 in Bari, Italy. The main structure is made of reinforced concrete including the cantilevered beams. You can of course use wood, steel or aluminum. You may slope the canopy enough to drain and tension enough to stop fluttering.
  
Picture 1. The Model

Picture 2. Cantilever Beam and Membrane Installation

Picture 3. Same as 2

Picture 4. Completion

Picture 5. In Use

David Chen?
从最近的帖子可以确认无疑您就是Geiger的陈先生了。
欢迎前辈参观指导。

膜做平并不是一个好主意。
  Bari的体育场因为本身建筑方案的立面较陡，还不会有大问题。膜过于平的话，结构刚度不好，容易积水积雪。可能这就是陈先生not to my liking designing a flat membrane 的原因吧。