Reinforced Concrete Storage Tank

[jsebbcons]

I have designed reinforced concrete structures in the past but have never designed a reinforced concrete tank. We are bidding a job now that will require such a tank and I will be tasked with the design. Does anybody know of a good technical resource or have any experience with reinforced concrete tank design.

This particular tank would be at grade (tank above ground)rectangular tank 14 by 16 and approximately 17 feet tall. Intuitively, I would think the design could be approached as a retaining wall with fluid loading.

 

[jike]

"Rectangular Concrete Tanks" by Javeed Munshi published by PCA.

 

[Splitrings]

We also use the reference jike listed.

Once you fix the corners of a wall, such as a tank, it no longer acts like a retaining wall. Tanks with height to length (or width) ratios as low as yours will likely have horizontal moments several times greater than vertical moments.

 

[oneintheeye]

it will be a retaining wall but fixed on 2 ends and bottom. As splings said it will generate horixontal moments. You could design as canitlever and provide equal RC horizontally but that would be overkill. There are many charts to give moments in plates supported on 3 sides. Remember to check the effect of the direct tension induced in the walls by the force on the wall perpendicular to it (if that makes sense). So horizontally you have moments and tension. Also in base if wall/base joint is fixed. You can pin the wall/base so wall spans horizontally but I don't think contractors like that detail to much. Your tank is pretty small really. May be governed by thermal steel. Cracking is important and crack widths should be controlled. In UK we go to 0.2mm (sometimes 0.1mm).

 

[JedClampett]

Even though this is a relatively small tank, the joint details are still critical. You need to decide if you want to use starter walls or depress the top reinforcing in the base slab to get in the waterstop. I would also design the base and sides as fixed, as opposed to pinned. Pinned supports are expected to crack and you're depending even more on the aterstop to function. For this size tank, the reinforcing shouldn't be too excessive. Don't be tempted to use walls less than 12 inches thick, even if your stresses allow it. Design for shear first, and reinforce as required.
If you could get your hands on some tank design drawings, you'll get some ideas on this. Also, don't forget to have the contractor leak test the tank before he turns it over to the owner.

 

[Splitrings]

An important consideration is whether this tank needs to meet ACI 350. ACI 350 requires a min. 12" thick wall, two mats of reinforcing and much lower stress levels in the reinforcing.

In the Dairy Industry we typically design our manure tanks to ACI 318. Many have 8" or 10" walls with single mats of reinforcing.

Better check with the AHJ.

 

[JAE]

Similar thread:
thread507-260620