Concrete Spun Pile Towers

Thank you very much Evgeny. I am looking at lowest cost possible. What about using spiral steel pipe of 3mm thick x 600mm X 12m length at the lowest section and joined together by flanges, reducing in diameter to 300mm at the top? Is there a better way than this?

Your comments and suggestion will be much appreciated.

George

What about using spiral steel pipe of 3mm thick x 600mm X 12m length

You mean a welded spiral steel pipe? In Russia this pipe is not for construction - it use for water supply, I think in other country it must be same usage.

For height 45m in Russia we make tower from 4 L-shape steel or 4 steel pipe joining as frame. At any case the steel pipe must be without spiral weld.
You must be consulted with licenced engineer for this question in your country with local buildings norm.

My engineer suggested spiral steel pipe. That is why I want to get second opinion through this forum if this is possible. Thanks anyway.

George

The cheapest way to do this is with radio antenna sections. They come in triangular cross-sections with various linear sizes and are capable of 1000 feet high or more.

They come in aluminium and steel, crank-up, etc. lots in the links

Yours will be a lot less, but doable. There are guyed and free standing. As a safety net you will experience side forces, so guywires to add strength in a particular direction will allow for a smaller tower. The weight of the fat lady shot from a cannon into the net will determine the tower strength

http://www.google.ca/#hl=en&source=hp&q=%22radio+antenna%22+%2Btower&btnG=Google+Search&aq=f&aqi=&aql=&oq=%22radio+antenna%22+%2Btower&gs_rfai=&fp=a2fde93a407aa350

http://www.google.ca/#hl=en&safe=off&q=tower+%2B%22free+standing%22&aq=f&aqi=&aql=&oq=tower+%2B%22free+standing%22&gs_rfai=&fp=a2fde93a407aa350