Steel water tower design

[rutzilla]

Hello everyone,
I've recently been handed my first steel water tower project (basic rectangular tower) and as a novice to steel design it has me floored. I'm capable of designing portal frames by hand calculations as per my undergraduate knowledge so I was hoping to get some guidance if possible.

1. the tower supports a 1.5 m dia x 2.25 m height tank on a chequred plate deck and is to be 12 m high (other dimensions are to my discretion). Can I get away with treating the structure as a simple statics problem to justify key section sizes or is it a lot more involving?
2. Any place I can get good materials to hone my skills on steel structures, for BS5950 especially?

Thanks for your time!

 

[dik]

You have vertical loads from the tank DL and LL. You have wind loading and snow loading to consider and you may have seismic loading... you have to establish the type of foundation, normally relying on a geotechnical report; the geotekkie may have some recommendations on the type of foundation to use as well as establishing site parameters for seismic activity. You have to safely carry these loads to the foundation capable of supporting them. Your code will establish the combinations of loading to consider.

Dik

 

[oldestguy]

This job is just in time to learn a lot or TO MAKE A BIG MISTAKE. You need practical guidance. Likely here you will miss providing one or two details that totally will make our recommendations from here useless. One way to get good ideas is to contact producers or contractors of these sort of tanks. With the OK of your boss, do this carefully with no guarantee of the job going to any one of them. However, you'd be much better off to be under the wing of an experienced tank designer. Perhaps the boss will OK some such help at least to bounce some progress work off for comments.

 

[JStephen]

In the US, elevated steel water tanks are usually designed to AWWA D100-11 (for municipal water storage) or NFPA-22 (for industrial fire protection). While either standard could be applied your tank, both assume tanks considerably larger than this. Both standards assume carbon steel welded construction with appropriate coatings and linings. On these larger elevated tanks, there will generally be a consultant that sizes the tank and specifies requirements, with the actual detailed design done by the manufacturers (who specialize in this type of work). That is likely not to be the case on a small tank like this.

Generally, these standards require higher wind loading than in the building codes, and lower allowable stresses than normally used for steel structural design.

 

[oldestguy]

Og again: While I don't do any tank designs, I'd not be surprised that there are "stock sizes" of tanks that you might find in a supplier's catalog and roughly the size you want. Why redo what already is done? He4re is,one that came up under the search "Water Tower Tanks".

https://phoenixtank.com/

 

[Ron]

As JStephen hinted, this is an odd design. It seems that you are designing a support tower to hold a pre-fabricated tank that just happens to supply water. I assume this is elevated so as to provide or assist with head pressure for the water distribution.

I'm in the US so not familiar with BS. As JStephen noted we design such to a couple of standards. In addition to what he noted, there are specific welding design considerations for steel ground storage and elevated tanks.

You have to design for loading in every orthogonal direction and consider corrosion protection in the process! Good luck and have fun!

 

[rutzilla]

thanks for the guidance everyone. to offer greater clarity, it looks like this;