P-M interaction diagram of Concrete section
P-M interaction diagram of Concrete section
(OP)
Hello all,
I have some doubt a P-M interaction diagram of concrete section.
I got a result as attached figure.
I think "It's OK", however any others told "It's NG".
I think it is OK, because Mr > phi Mn.
Any others told design force is not placed inside P-M line, because it's NG.
I want to hear your opinions.
Thank you!
Section properties (Uni-axial)
H = 800 mm
B = 1000 mm
f'c = 33.2 MPa
fy = 400.0 MPa
As'1 = As'2 = As = 3216.8 mm2
ds'1 = 116.4 mm
ds'2 = 154.4 mm
ds = 683.6 mm
Pu = -3089 kN (tension)
Mu = -91 kN.m (tension of top surface)
I have some doubt a P-M interaction diagram of concrete section.
I got a result as attached figure.
I think "It's OK", however any others told "It's NG".
I think it is OK, because Mr > phi Mn.
Any others told design force is not placed inside P-M line, because it's NG.
I want to hear your opinions.
Thank you!
Section properties (Uni-axial)
H = 800 mm
B = 1000 mm
f'c = 33.2 MPa
fy = 400.0 MPa
As'1 = As'2 = As = 3216.8 mm2
ds'1 = 116.4 mm
ds'2 = 154.4 mm
ds = 683.6 mm
Pu = -3089 kN (tension)
Mu = -91 kN.m (tension of top surface)






RE: P-M interaction diagram of Concrete section
What type member is this in your structure?
RE: P-M interaction diagram of Concrete section
And it is a result from vertical wall of well foundations.
Thus, sections are subjected high tensile force locally.
RE: P-M interaction diagram of Concrete section
What you were told is correct; the applied force and moment combination must be inside the interaction diagram line.
Also the interaction diagram seems to be wrong, as it shows a maximum tensile capacity well over 3000 kN.
Doug Jenkins
Interactive Design Services
http://newtonexcelbach.wordpress.com/
RE: P-M interaction diagram of Concrete section
Doug Jenkins
Interactive Design Services
http://newtonexcelbach.wordpress.com/
RE: P-M interaction diagram of Concrete section
RE: P-M interaction diagram of Concrete section
Dear, hokie66
The reinforcing steel is consist of total 3 layers.
1st(As'1) and 2nd(As'2) is top layer and each area is 3216,
3rd(As) is bottom layer and area is 3216.
Thus, total reinforcing steel area is 3216*3 = 9648mm2.
Thanks for your attention.