The slabs are mostly there to carry the walls and to keep liquid from leaking into the ground. As such most of the references don't really address the slab.
You need to get the PCA publications "Design of Rectangular Tanks" and/or "Design of Circular Non-Prestressed Tanks." Also, you need ACI 350-05.
But if the slab supports the walls and doesn't leak, it's done its job.
Thanks a million. I will get these refs. Do you design slab for +ve moment at mid-span since there are equipment loads (dead loads) and -ve moment at ends at walls; or is it a slab-on-grade?
Steve/jedClampett: Thanks for your responses. I got the PCA references. Also thanks for your recommendation. I agree the slab will support the walls.
I will design the slab as a structural slab using plate coefficients with load distributed from the walls. I will not account for the load from the liquid since it will transferred to foundation directly through slab.
I will assume fixed conditions at wall interface and compare that to wall fixity and design for higher moments. I assume wall moments at wall/slab bottom end will control. For positive moment in slab I will assume hinged condition. I will also take into account uplift forces.
Please don't be offended, but I don't think you should be taking on a wastewater tank without some experienced supervision. I think it's more complicated than you realize, and, I don't think this forum is the proper place to learn how to design a tank.
I think you will be able to design this, now that you have the PCA reference. If you are in a seismic area, there is also a design reference on the seismic design of tanks.
Thanks for your opinion. My intention was not to use forum to teach me how to design. We are all professionals. Tank problem is not a complicated structure. Others in forum pointed me in right direction and that is greatly appreciated. Thanks...
newbridge:
You stated you got the PCA references. Did you get a copy of ACI 350 as well? For wastewater tanks ACI 350 has design requirements that you may not find in the PCA books.
Yes, I got ACI 350-06 and ACI 350.4R-04. Second doc includes design considerations...very usefull. Thank you. I think I have all the ref that I need....
