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09-12-2008, 08:09 PM #1
- Join Date
- Apr 2006
- North of Escondido, San Diego
- Kubota L4330****RTV 900
Sizing Rebar for 14 ft diam x 9 ft tall concrete block water tank, hoop stress
I have my degree in Civil Engineering but I don't trust my calcs. I worked as a surveyor for 25 years and am now retired. I know the structural guys don't want to design this thing for me. I just want a yes or no or you're off by a factor of two or you forgot to include???
The firewater resevoir tank will be 13.8 ft inside diameter and ten feet high but nine feet of water depth. The walls will be 12 inch bond beam block with 5/8 in rebar in each course with about six ft overlap.
I figure the hoop stress to be 5000 psi. 5/8 rebar will give me 12000 psi. That's about 18000 psi per evey eight inches block course. That gives me 3 x more than I need????? Am I missing something? off by a factor of two??
If the hoop takes care of the water pressure do I have to deal with shear stress at the base? I am going to put rebar 3 ft into a four+ inch thick floor on terra firma and bent up five feet into the wall. I am not sure why I need this as the hoop stress should handle the deep water forces. However for general reasons I think I need to put this about every forth hole or 32 inch on center.
Earthquakes are another issue. I am in a low risk area. However dealing with the issue is also a concern. If this thing breaks there is no safety issue with what lies below.
ZeuspaulKubota Grand L4330,FEL, Box Blade, Brush Mower, Tiller, Sub Soiler....RTV 900