Pseudo-code for elastic analysis of a layered reinforced concrete section under eccentric axial load and pre-stress load:
‘For each reinforcement layer: Find area, first moment of area about top ,and depth of centroid.
Find total reinforcement section properties over all layers
For each reinforcement layer: adjust section properties for compression from the top surface to the layer.
‘For each concrete layer:
Find area, first and second moments of area about base of layer ,and height of centroid above base.
Find the number of reinforcement layers in the compression zone.
Find composite transformed properties about the base of each layer.
Find the centroid depth for the complete composite section in compression, and the reinforcement in tension.
Find the total prestress force and moment about the concrete centroid.
Find total axial force and bending moment, and nett axial force eccentricity from the concrete centroid and top face.
Check compression face.
If the compression face is bottom face, reverse layers and recalculate section properties.
Find the concrete layer containing the Neutral Axis.
If the Neutral Axis is above the top face (section entirely in tension) or below the bottom face (section entirely in compression) then:
Find top and bottom face stresses and position of NA using stress = P/A + M/Z
Find parameters for Neutral Axis equation
Solve Neutral Axis equation
Adjust for reinforcement layers in the bottom concrete layer, below the Neutral Axis.
Find composite transformed section properties about the Neutral Axis
Find top and bottom face stresses.
Find stresses and strains at each reinforcement layer and top and bottom face.
Find concrete, reinforcement and total axial forces.
Find concrete, reinforcement and total moments.