Spiral Staircase design
(4/48)
Description
Riser "R"
Tread "T"
width of steps and Landing"B"or bw
Inner radius " Ri"
Outer Radius "Ro" = Ri+B
Thickness of slab "h"
Eff. Depth "d"
Plan angle of the stair "α "
Vertical angle at the step
centreline with horizontal " Φ "
Self Weight of slab
Floor Finish
weight of steps
Total dead Load "Udl"
Live load
Total service Load "tsl"
Total Ultimate Load "w"
Total Ultimate Load for full width"wu"
Weight of reinforced concrete "γrc"
Strength of concrete "fc"
Strength of steel "fy"
Clear cover to concrete
Flexure strength reduction factor
Shear strength reduction factor
Modulus of Elasticity of steel "Es"
Modulus of Elasticity of concrete "Ec"
Modular Ratio "n = Es/Ec"
Dia of top of bars
Dia of bottom of bars
Dia of closed hoop bars as distribution
Ast top full width
Asb Bottom full width
Closed hoops per m
Top steel "Ast" mm2
Bottom steel "Asb"mm2
2 legged Closed hoops steel
Calculation Reference
Concrete Design
Beam Design
Stair Design
Calculation Preview
(4/48)
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