Design of Water Retaining Structures - Flexural vs Thermal stresses 3

[Karlos80]

Hi there,

I am involved in design of a complex 2 storey reinforced concrete tank ,size approx. 33m x 100m. The tank will be piled.
The tank will be subjected to significant differential settlement. The walls have expansion joints. The base was designed as a stiff plate to cope with the differential settlement and no movement joints were proposed.

Based on some publication (including CIRIA C660) it is stated that it is not a good practice to add flexural stresses to thermal stresses. And the tank is being designed on this basis. If I am required to combine this than I would have problem to size the tank to comply with the crack width limits. And to be honest I have never done it before, but my previous projects were for a simple buried tanks. In this case it is tank above ground with suspended floor.

However, I have still thoughts regarding the large suspended floor (stiff plate). I have read the CIRIA C660 and they also do not combine the thermal and flexural cracks.
What are your views on this, can you suggest some good publications/books about this?

Thanks
Karol

 

[oldestguy]

Having never done this kind of job before, I'd involve an expert on a consulting basis, rather than look here.

 

[JedClampett]

If the tank is on piles, why is there differential settlement? Can't you drive the piles to a firm stratum?
With expansion joints, I see a leaky tank in your future. If the base has no expansion joints and the walls have expansion joints, you'll have cracks in the slab where the expansion joints meet the slab.
You state that the tank has a suspended floor. Is it suspended over something, or is it just designed as suspended because it is on piles?
Son, I don't know you, but frankly you're out of your league. I'm not sure I'd be comfortable with this, and I've been doing tanks for 20 years.