uniaxialMaterial('FRPConfinedConcrete', matTag, fpc1, fpc2, epsc0, D, c, Ej, Sj, tj, eju, S, fyl, fyh, dlong, dtrans, Es, nu0, k, useBuck)

This command is used to construct a uniaxial Megalooikonomou-Monti-Santini concrete material object with degraded linear unloading/reloading stiffness according to the work of Karsan-Jirsa and no tensile strength.

matTag (int) integer tag identifying material
fpc1 (float) concrete core compressive strength.
fpc2 (float) concrete cover compressive strength.
epsc0 (float) strain corresponding to unconfined concrete strength.
D (float) diameter of the circular section.
c (float) dimension of concrete cover (until the outer edge of steel stirrups)
Ej (float) elastic modulus of the fiber reinforced polymer (FRP) jacket.
Sj (float) clear spacing of the FRP strips - zero if FRP jacket is continuous.
tj (float) total thickness of the FRP jacket.
eju (float) rupture strain of the FRP jacket from tensile coupons.
S (float) spacing of the steel spiral/stirrups.
fyl (float) yielding strength of longitudinal steel bars.
fyh (float) yielding strength of the steel spiral/stirrups.
dlong (float) diameter of the longitudinal bars of the circular section.
dtrans (float) diameter of the steel spiral/stirrups.
Es (float) elastic modulus of steel.
nu0 (float) initial Poisson’s coefficient for concrete.
k (float) reduction factor for the rupture strain of the FRP jacket, recommended values 0.5-0.8.
useBuck (float) FRP jacket failure criterion due to buckling of longitudinal compressive steel bars (0 = not include it, 1= to include it).


#.IMPORTANT: The units of the input parameters should be in MPa, N, mm. #.Concrete compressive strengths and the corresponding strain should be input as positive values. #.When rupture of FRP jacket occurs due to dilation of concrete (lateral concrete strain exceeding reduced rupture strain of FRP jacket), the analysis is not terminated. Only a message “FRP Rupture” is plotted on the screen. #.When $useBuck input parameter is on (equal to 1) and the model’s longitudinal steel buckling conditions are fulfilled, a message “Initiation of Buckling of Long.Bar under Compression” is plotted on the screen. #.When rupture of FRP jacket occurs due to its interaction with buckled longitudinal compressive steel bars, the analysis is not terminated. Only a message “FRP Rupture due to Buckling of Long.Bar under compression” is plotted on the screen.

See also