# Challenge To Build The Tallest Tower

1. Sep 29, 2006

### dratcliff

Hi, I just popped in to see if there are any budding young engineers here (hope I got the right forum) interested in helping with a problem that I have been nutting out over the years... Hope your forum can help.

It is all about controlling sway and buckling of members and gaining the full compressive strength of materials... steel in particular.

My theory is that... If, provided that you could artificially control against buckling and swaying, steel has the ability to withstand almost 4,000 metres in height (uniform section) before it crushes from its own self weight/gravity... So, if we can control against sway and buckling with a type of webbing, and depending on the weight of the webbing (maybe down to 10% of the core weight), a uniform steel tower should reach a height of around 3,500 metres (tapered 7,000 metres).

I have started a thread on a catapult forum posing the question/challenge, so if anyone is interested in joining in and solving the problem, I would welcome your input.

http://www.thehurl.org/tiki-view_fo...mode=commentDate_desc&topics_find=&forumId=2"

With thanks,
David

(If you have any questions I will reply here if you like)

Last edited by a moderator: Apr 22, 2017
2. Sep 29, 2006

### J77

3. Sep 29, 2006

### dratcliff

I am assuming that as the tower would be fully rigid it would also be fully earthquake and cyclone proof... and as it would be tapered, the upper section would have some give and be allowed to sway slightly... absorbing the energy from an earthquake.

Yes, it's not that far from where I live actually... The thermal tower (situated at Mildura), 1,000 metres high, was proposed to be made from reinforced concrete. From memory the size of a football field at the base, 1.2 metres thick and tapers up to 40 or so metres diamater at the top with 400mm wall thickness... I did contact the original designer in Germany as well as the people who were handling the job, but was met with absolute ignorance and arrogance from both... I even made up a design of my own using steel that would have been a fraction of the cost and a lot easier to build. http://groups.msn.com/TrussTesting/towerormast.msnw?Page=Last" [Broken]

Last edited by a moderator: May 2, 2017
4. Sep 29, 2006

### Pyrrhus

I am interested in this. Why do you say your design is "more economic"?, usually reinforced concrete is cheaper than steel. I will like to see the tower design.

5. Sep 30, 2006

### dratcliff

Cyclovenom,

Well for a start you would not need any scaffolding as the steel design http://groups.msn.com/TrussTesting/towerormast.msnw?action=ShowPhoto&PhotoID=150" [Broken] has external posts and webbing, so can be used instead.

They were planning on using a slip form for the concrete and would have had to pour continuously until they reached the top as well as fit the reinforcing prior to pouring... Big and risky job.

The steel idea would be very simple and quick and safe to construct. Check the links in my earlier post for more info.

Another thing too. "normally" when using steel you would expect there to be a lot of it for such a height as it needs to be bulky in order to fight against swaying and buckling... With my design, you have the inner webbing to stop the buckling and the outer web to control the sway... so the main columns are a lot stronger and can remain thinner and more economic... Lighter, stronger and more rigid.

Last edited by a moderator: May 2, 2017
6. Oct 2, 2006

### dratcliff

I should mention that the design for the thermal tower was an earlier one, before I put this all together as it is now... It would actually be much lighter. The main ingredient is the two sets of diagonal bracing... There is no need for the outer chord to be a compression member, where it only needs to take tension... and the same goes for the middle chord.

That probably wouldn't make a lot of sense to anyone that has had any training in the area as you would argue that there needs to be at least two chords in compression to basically 'fight back'... I should redo it I guess...

The designer of the proposed tower also had a bicycle wheel type fixture inside the funnel every so many metres to stop the thing from screwing on its axis...

7. Oct 2, 2006

### dratcliff

http://groups.msn.com/TrussTesting/towerormast.msnw?action=ShowPhoto&PhotoID=154" [Broken]

Last edited by a moderator: May 2, 2017
8. Oct 4, 2006

### Dark-half

Is there any specific design you're hoping to exhibit? Strictly vertical 'tower/skyscraper' or would any shape work?

Because if you're trying to make the highest tower -- er well, lets take sand for an instance, stuff it in a toiletpaper tube with tissue on the bottom held in place by a rubber-band now ram a wooden dowel hard into the tube, the weight/force gets displaced outward, correct? What if you impliment a design that would take the weight off and spread it outward instead of strictly downward like most skyscrapers. Granted it may not be the most economical or space saving, but if it's height you're going for. I believe this is the way to go...

http://img182.imageshack.us/img182/5821/ideaqi4.jpg [Broken]

Tell me what'cha think. I want to know if I'm an idiot or genius in the making.

(Excuse me if I didn't really read all the posts and missed something. )

Last edited by a moderator: May 2, 2017
9. Oct 5, 2006

### dratcliff

Well the tower could be tapered, but going by the axial compression tables should'nt need to be as steel will reach a height of just under 4,000 metres... provided you could supply full artificial lateral restraint. So then if you could achieve even 2,000 metres, tapering would give you 4,000 metres.

(From the catapult site http://www.thehurl.org/tiki-view_fo...mode=commentDate_desc&topics_find=&forumId=2")

Last edited by a moderator: Apr 22, 2017