CALCS PROC037
STRUT, STABILITY, PERRY ROBERTSON

NOTATION

Aarea,strut csa
I2nd mom area
Llength,effective
arobertson's constant
Pcforce, applied
Festress, euler buckling
rmin rad of giration
Sslenderness ratio
S0slenderness ratio
etaperry factor
Fcrstress, critical, perry robertson

APPLICATION

Straight compression member

OUTPUT

Inelastic stability critical stress

SEE ALSO

other porcs & progs

THEORY

Structural Analysis, Coates Coutie & Kong

GUIDANCE

Consider also local stability of cross section components.
Values of Robertson's Constant a.
Section t mm 1U'a' for buckling axes-
xx yy any
Rolled UB - 2. 3.5 -
Rolled UC<40 3.5 5.5 -
>40 5.5 8.0 -
UB & UC, Fabricated<40 3.5 5.5 -
>40 3.5 8.0 -
UB & UC, Rolled with welded<40 3.5 - -
flange cover plates >40 2.0 - -
BOX, welded<40 - - 3.5
>40 - - 5.5
CH, Angle & Tee, rolled - - - 5.5
Structural Hollow Section - - - 2.0
Round Square Flat<40 - - 3.5
>40 - - 5.5
Compound rolled sections - - - 5.5
Back-to-back Angle, CH, Tee - - - 5.5
Two Laced or Battened Sections - - - 5.5
Lattice Strut - - - 2.0

INPUT FORMAT

LET Nm=:Nk=:A=:I=:L=:a=:P=:PROC037

EXAMPLE

Call Statement

LET Nm=1:Nk=1:A=36:I=239:L=190:a=3.5:Pc=2*68:PROC037

Output

PROC037 EL.STABILITY, STRUT, PERRY ROBERTSON, Rev 180995
Fe= PI^2*E(Nm)*I/(L^2*A)= 3.757
r= SQR(I/A)= 2.577
S= L/r= 73.74
S0= .2*SQR(PI*E(Nm)/Fy(Nm))= 8.621
eta= .001*a*(S-S0)= 0.2279
Fcr= (Fy(Nm)+(1+eta)*Fe)/2-SQR(((Fy(Nm)+(1+eta)*Fe)/2)^2-Fy(Nm)*Fe)= 2.238
UF= ABS(P/A)/(Kcr(Nk)*Fcr)= 0.09632
END037