DESIGN OF LIQUID RETAINING MEMBER AS PER IS 3370 : 2009

 PROGRAM INFO / LIMITATIONS.

This program designs reinforced concrete beam/slab/wall liquid retaining      member as per the given loading. 
Fy  = 415 N/mm2 . Fy should not exceed 500 N/MM2.
Reinforcement spacing is restricted to 300 MM or Member Depth whichever is Less.
The program designs the member as "Plain Concrete" member, if the gross      tensile stress is within  the permissible limit. 
The permissible stress in steel is restricted to 130 N/MM2 even when Bending
     Tension is away from liquid face.
Mature Conc. Crack width calculations are given for academic purpose only. 
    Effect of axial loads are not considered in these calculations. Moment of inertia of
    concrete is only considered, contribution of reinforcement is neglected.
Minimum Conc. Grade shall be M 30 for RCC & M 20 for PCC Tanks.
Maximum Cement Content = 400 Kg/M3 excluding Fly ash, GGBS & etc.
For PCC Minimum Cement Content = 250 Kg/M3 { 5.0 Bags } & Max. W C = 0.50
For RCC Minimum Cement Content = 320 Kg/M3 { 6.4 Bags } & Max. W C = 0.45
1st Time Filling Rate for Tank shall not Exceed 1 M / 24 Hours for Crack Control.
Movement Joints shall be as per Standard Details.
Containment of Liquids above ambient temperature may cause conc. cracking.
W C can be controlled by using largest possible coarse aggregates & plasticizers.
Minimum Curing Time for Tanks shall be 14 days.
U/G water tanks shall be founded on Sliding layer to minimize restrain.
Blinding (PCC) layer shall be minimum of 75 MM thick.
Sliding Joint can be prepared by making surface flat using steel float & rubbing
     with carborundum stone. Break bond by using painting or inserting paper.
Provide haunch at all vertical corners for horizontal BM, even though walls are 
    designed as vertical prop / simple cantilever.

PERMISSIBLE CONCRETE STRESSES IN CALCULATIONS RELATING TO RESISTANCE TO CRACKING FOR MEMBERS HAVING TENSION ON LIQUID FACE
GRADE OF CONCRETE
 
SHEAR  PERMISSIBLE STRESS (KG/CM2)
(KG/CM2)
DIRECT TENSION
BENDING TENSION
M 20 17 12 13
M 25 19 13 18
M 30 22 15 20
M 35 25 16 22
M 40 27 18 24
M 45 27 20 26
M 50 27 21 28
 

IN STRENGTH CALCULATIONS THE PERMISSIBLE STRESSES IN STEEL ARE AS FOLLOWS

I
TENSILE STRESS IN STEEL IN DIRECT TENSION [KG/CM2]
1300
II
TENSILE STRESS IN STEEL IN BENDING TENSION  ON LIQUID FACE [KG/CM2]
1300
III

COMPRESSIVE STRESS IN STEEL [KG/CM2]

1400