The R/C Spiral Stairs software can be used for design and analysis of reinforced concrete spiral stairs.  All internal actions, including the bending moments about both axes, torsion, shear and the axial load are evaluated.  The results are provided in several points along the span.  All internal actions are considered in the design of the longitudinal and shear steel.  The analysis is based on Finite Element Method, implementing a high order Shell element.

Key Features:

• Bi-axial bending, shear and torsion
• Self weight automatically included
• Design of longitudinal steel for bending in Mx, My and torsion
• Design of stirrups for shear and torsion
• Follows AS 3600
• One page detailed report:

Analysis and Strength Design of R/C Spiral Stairs, AS3600

40, 16/10/2008, 18:32

Floor to Floor Height, m: 2.7
Number of Risers: 16
Internal Radius, m: 1.5
Stair Width, m: 1.35
Stair Angle (start to end), deg: 120
Additional Dead Load, kPa (horizontal projection): 6
Live Load, kPa (horizontal): 4
Concrete Cover, mm: 40
Concrete, MPa: 40
Bars Size: N16
Steel, MPa: 500
Stirrups (Ties) Size: N12
Slab Thickness, mm: 169

Riser (Step) Height: 0.169 m
Number of Treads (Horizontal Steps): 15
S1, Tread (Step) Width at the Internal Edge, mm: 209
S2, Tread (Step) Width at the Mid-Line, mm: 304
S3, Tread (Step) Width at the Outside Edge,mm: 398
Self Weight of the Steps per Width, kN/m': 2.73 (horizontal)
Self Weight of the Slab per Width, kN/m': 6.53 (horizontal)
Additional Dead Load per Width, kN/m': 8.10 (horizontal)
Live Load per Stairs Width, kN/m': 5.40 (horizontal)
Total Dead Load per Stairs Width, kN/m': 17.36 (horizontal)
Design Load per Width, kN/m': 28.93 (horizontal) 1.2*DL+1.5*LL



Mx Steel: 3N16 top & btm. Total No of Mx bars: 6N16
My Steel: 3N16 left and right. Total No of My Bars: 6N16
Total No of Bars for Bending Strength in Both Directions : 12N16
Total Longitudinal Steel for Bending Strength: 1.05%
No cracks control.

Ends: No Shear Stirrups Required. (start end end)
Ends: Vuc: 149.5, Sx: 17.3 kN
Mid-span: Shear Stirrups N12 at Distance: 500 mm
Mid-span: Shear Stirrups Number of Vertical Legs: 2
Mid-span: Vuc: 137.1, Sy: 87.7 kN

Torsion Stirrups (Ties) N12 at 120 mm (start and end)
Torsion Stirrups (Ties) Number of Vertical Legs: 4 (start and end)
All Torsion Stirrups (Ties) Must be Closed.
Additional Lonitudinal Bars for Torsion: 2N16

Total Number of Longitudunal Bars for M & T: 14N16
Total Longitudinal Steel for Bending and Torsion: 1.23%
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