• Design properties for concrete and reinforcement materials are selected by user.

  • Modulus of elasticity, Ec and Shear Modulus is calculated automatically according to the selected material’s design property.


Ec = modulus of elasticity of concrete, psi
Es = modulus of elasticity of reinforcement, psi
fc' = specified compressive strength of concrete, psi
fy = specified yield strength for nonprestressed reinforcement, psi
εs = strain value of reinforcement
εy = yield strain of reinforcement
wc = density, unit weight, of normal weight concrete, lb/ft3

Concrete Design Properties

Specified compressive strength

The compressive strength of the concrete material used in reinforced concrete elements is shown with fc'. ACI defines a minimum value of fc' for structural concrete and there is no limit for the maximum value. Limit values for fc' are shown in ACI Table

Modulus of Elasticity

Modulus of elasticity Ec , for concrete is calculated as shown in ACI Equation

Nonprestressed Reinforcement Bars Design Properties

For nonprestressed reinforcement bars, the stress value below fy is equal to Es times εs which is the value from the strain diagram at the location of the reinforcement. For strains greater than that corresponding to fy, stress is constant and equals to fy.

Modulus of elasticity, Es, for nonprestressed reinforcement bars is considered as 29,000,000 psi.

Yield strength for nonprestressed reinforcement bars shall not exceed the values given in ACI Table and Table

Information on sizes, areas, and weights of various steel reinforcement is presented below.

Equivalance Between U.S. Customary Units, SI-METRIC, and MKS-METRIC of specified compressive strength, fc' and specified yield strength for reinforcement fy are shown below

U.S. Customary units stress in pounds per square inch (psi)

SI-metric stress in MPA

mks-metric stress in kgf/cm2

fc' = 3000 psi

fc' = 21 MPa

fc' = 210 kgf/cm2


fc' = 4000 psi

fc' = 28 MPa

fc' = 280 kgf/cm2

fc' = 5000 psi

fc' = 35 MPa

fc' = 350 kgf/cm2

fc' = 6000 psi

fc' = 40 MPa

fc' = 420 kgf/cm2

fy = 40,000 psi

fy = 280 MPa

fy = 17,600 kgf/cm2


fy = 60,000 psi

fy = 420 MPa

fy = 19,000 kgf/cm2