movement& construction joins in tanks

[zohl]

could anyone please help explaining to me how could we make contraction joint in the walls of a circular tank knowing that the resisting mechanism is achieved by direct tension ( ring tension) because i think that such joints would break the resisting mechanism and the wall will only resist the lateral pressure by flexure ( vertical cantilever action). thanks

 

[bimr]

Please review:

Link

 

[zohl]

thank you bimer for these specialty types of joints of which i didn't have an experience but still my concern remains: are we still good dealing with the ring tension equation: t=pr ?!

 

[HTURKAK]

I suspect you are looking for construction joint rather than contraction joint...If the reinforcement is cut at CJ or EJ , you can not use the hoop tension formula.. The ring wall shall be designed as cantilever wall.( similar to the retaining walls )..
Moreover, it is common practice conservatively ,to design as cantilever wall the circular tank walls ..

If you provide more info.( size and depth of the tank, temperature etc..) you may get better responds..

 

[zohl]

thanks HTURKAK THE TANK IS TRICKLING TANK OF 20 m diameter and 3.5 m height with 0.5 m freeboard and 2 m depth of natural (gravel) filer media supported on perforated platform which i am planning to use heavy duty grating. about the temp. it is high temp and high humidity ( red sea coast). any advising help will be gratefully appreciated

 

[HTURKAK]

For dia . 20m, my suggestion will be, no need to expansion and contraction joints.. If you have the full set formwork, the wall could be poured with single shot. Otherwise, provide CJ with waterstops and continuous rebar . acc to formwork available ..may be 6 segments. The wall thick. could be 30 cm.

Good luck..

 

[JedClampett]

I agree with HTURKAK that no expansion or contraction joints should be used. But I'd add construction joints with waterstop at 6th points to reduce pours to about 10 meters each.