Interaction Diagram - Axial Load

Concrete Strength f'c		gross area Ag	{{Ag()}} sq.in
Steel Strength fy		Density ρg	{{rhog()}}
Elastic Modulus Es		Yield Strain εy	{{ey()}}
Width of Column b		Concentric Axial Load @ A
Height of Column h		Axial-Load Capacity Po	{{Po()}} kips
Area of Steel Ast		Effective, Po @ A'	{{fiPo()}} kips
		Max Axial Load φPnmax	{{fiPoMax()}} kips

Section Parameters

depth to neutral axis c computed using compression strain in concrete 0.003

@ point B z=0, point C z=-1, point D z=-2.5, point E z=-4

As you change the value of z, the computed φPn & φMn will be recomputed

c - depth to neutral stress, a - depth of compression section

Z value
Section Centroid y
c = {{c()}} in	a = {{ac()}} in	Beta β = {{beta()}}

Compute Nominal Force and Moment

Depth	to Steel	Area	of Steel	εsi	fsiksi	Fsikips	Mnkip-ft
dt		Ast		{{est()}}	{{fst()}}	{{Fst()}}	{{Mnt()}}
d2		As2		{{es2()}}	{{fs2()}}	{{Fs2()}}	{{Mn2()}}
d3		As3		{{es3()}}	{{fs3()}}	{{Fs3()}}	{{Mn3()}}
d4		As4		{{es4()}}	{{fs4()}}	{{Fs4()}}	{{Mn4()}}

Compressive Force in Concrete Cc	{{Cc()}} kips
Nominal Axial Capacity Pn	{{Pn()}} kips	Effective φPn	{{fiPn()}}
Nominal Moment Capacity Mn	{{Mntot()}} kip-ft	Effective φMn	{{fiMn()}}